CN1706050A

CN1706050A - Stacked photoelectric converter

Info

Publication number: CN1706050A
Application number: CNA2004800014136A
Authority: CN
Inventors: 佐佐木敏明; 小井洋平; 山本宪治; 吉见雅士; 市川满
Original assignee: Kaneka Corp
Current assignee: Kaneka Corp
Priority date: 2003-07-24
Filing date: 2004-07-15
Publication date: 2005-12-07
Anticipated expiration: 2024-07-15
Also published as: CN100420039C; JP2005045129A; JP4063735B2

Abstract

A stacked photoelectric converter comprising a plurality of stacked photoelectric conversion units (3;5) each including one conductivity type layer (31;51), a photoelectric converting layer (32;52) of substantially intrinsic semiconductor, and a reverse conductivity type layer (33;53) that are formed on a substrate (1) sequentially from the light incident side. At least one of the reverse conductivity type layer (33) in the front photoelectric conversion unit (3) arranged relatively on the light incident side and the one conductivity type layer (51) in the rear photoelectric conversion unit (5) arranged contiguously to the front photoelectric conversion unit (3) includes a silicon composite layer (4). The silicon composite layer (4) has a thickness of 20-130 nm and an oxygen concentration of 25-60 atm%.

Description

Stacked photoelectric converter

Technical field

The present invention relates to the improvement of the conversion efficiency of film photoelectric converting means, particularly relate to the improvement of conversion efficiency that lamination has the lamination type film photoelectric converting means of a plurality of photoelectric conversion units.In addition, " crystalloid " in the present specification reaches the term of " crystallite " as used in this area, also is used for the part and contains amorphous situation.

Background technology

In recent years, for the cost degradation and the high efficiency that make photo-electric conversion device are set up simultaneously, consider that from the viewpoint of resource also almost no problem film photoelectric converting means receives publicity, its exploitation is carried out energetically.The film photoelectric converting means is just expected in the application of various uses such as solar cell, optical sensor, display.As a kind of uncrystalline silicon photo-electric conversion device of film photoelectric converting means owing to can at the bottom of large-area glass substrate or the stainless steel lining, form at low temperatures, so can expect cost degradation.

Contain first electrode of sequential laminating on the insulating properties substrate, above semiconductive thin film photoelectric conversion units, and second electrode on the common surface of film photoelectric converting means.And a film photoelectric converter unit contains the i type layer that is formed layer structure by p type layer and n type layer.

The i type layer that the major part of film photoelectric converter unit thickness is used as intrinsic semiconductor layer in fact occupies, and the light-to-current inversion effect mainly produces in this i type layer.Therefore, i type light-to-current inversion layer is for carrying out light absorption, and preferably with its thickening, but as thickening more than the necessary thickness, then its accumulation will expend cost and time.

On the other hand, p type and n type conductive layer have in photoelectric conversion units the effect that produces diffusion potential, by about the size of this diffusion potential as the value of the open circuit voltage of one of film photoelectric converting means key property.But these conductive layers are to the inoperative not active layer of light-to-current inversion, and the light that absorbs by the impurity that is doped in the conductive layer does not have generating to lose.Therefore, the thickness of p type and n type conductive layer is so long as then preferably thin as far as possible in the scope that can produce abundant diffusion potential.

In addition, in photoelectric conversion units or the thin film solar cell, no matter the p type and the n type conductive layer that are contained in it are noncrystalline or crystalloid, the i type light-to-current inversion layer that occupies its major part be noncrystalline be called as noncrystalline photoelectric conversion units or amorphous thin film solar cell, i type layer be crystalloid be called as crystalloid photoelectric conversion units or crystalloid thin film solar cell.

Usually, at the semiconductor that is used for the light-to-current inversion layer, along with light wavelength increases, the absorption coefficient of light reduces.Particularly when the light-to-current inversion material is film,,, be restricted so the light-to-current inversion amount depends on the thickness of light-to-current inversion layer owing to can not produce sufficient light absorption in the little wavelength region may of absorption coefficient.Therefore, taked following measure, be difficult to the light scattering structure of escaping, the optical path length of essence has been increased, produced fully and absorb, produced big photoelectric current to the outside by being formed into the light that is mapped in the photo-electric conversion device.For example, during from transparent substrate side incident, the light incident side electrode uses its surface to contain the reticulate pattern nesa coating of fine concaveconvex shape at light.

In addition, improve the known method that has two above photoelectric conversion units of lamination to form lamination type film photoelectric converting means of method of the conversion efficiency of film photoelectric converting means.In the method, the place ahead photoelectric conversion units that contains light-to-current inversion layer in the light incident side configuration of photo-electric conversion device with big band gap, and contain the rear photoelectric conversion units of (for example Si-Ge alloy) light-to-current inversion layer with the band gap that reduces gradually in configuration thereafter, thereby can in the wide wave-length coverage of incident light, carry out light-to-current inversion, thus, seek raising as the conversion efficiency of device integral body.In stacked photoelectric converter, the device that contains noncrystalline photoelectric conversion units and crystalloid photoelectric conversion units is called as the hybrid optical electric conversion means.In the hybrid optical electric conversion means, the light wavelength that uncrystalline silicon can carry out light-to-current inversion is about 800nm at long wavelength side, but because can making than the light of thinking about the long about 1100nm of this length, crystalloid silicon carries out light-to-current inversion, so can in the wideer wave-length coverage of incident light, carry out light-to-current inversion effectively.

But in stacked photoelectric converter, because each photoelectric conversion units that is connected in series, the short-circuit current density (Jsc) of pretending to photo-electric conversion device is limited by the value of minimum in the current value that is produced by each photoelectric conversion units.Therefore, the current value of each photoelectric conversion units is preferably impartial, and the absolute value of electric current is big more, can expect the raising of conversion efficiency more.In stacked photoelectric converter, between a plurality of photoelectric conversion units, be provided with sometimes and have reflector in the middle of both conductivity of photopermeability and light reflective.At this moment, because the part of the light in reflector is reflected in the middle of arriving, so, increase the electric current that produces more leaning on the uptake that can increase light in the place ahead photoelectric conversion units of light incident side than middle reflector.That is, effective thickness of this place ahead photoelectric conversion units is from seeing increase in appearance.

For example, in the middle of in the hybrid optical electric conversion means that the crystalloid silicon photoelectric conversion units by the uncrystalline silicon photoelectric conversion units in the place ahead and rear constitutes, inserting during the reflector, can not increase the thickness of uncrystalline silicon light-to-current inversion layer, and the electric current that utilizes this place ahead photoelectric conversion units to produce is increased.In addition, compare during the reflector during reflector with in the middle of not containing in the middle of containing, owing to can be reduced to the thickness that obtains the needed uncrystalline silicon light-to-current inversion of identical electric current layer, therefore, the characteristic that can suppress the uncrystalline silicon photoelectric conversion units that causes because of the significant light deterioration (Sraebler Wronsky effect) of the increase of uncrystalline silicon layer thickness reduces.

Reflector many ITO (indium tin oxide) or the such TCO (transparent conductivity oxide-film) of ZnO by polycrystalline in the middle of existing, particularly ZnO forms.But, because the reflector is formed by sputtering method or spray-on process etc. in the middle of the ZnO, so usually need to use and the different film formation device of the plasma CVD that is used to form semiconductor film (chemical gaseous phase accumulations) device, thus generation increase equipment cost, and the problem that also prolongs of production process time.In addition, when using sputtering method to form the ZnO layer, might make the characteristic of base semiconductor film low because of sputter damage.

In addition, for suppressing the harmful effect of stacked photoelectric converter, need form good Ohmic contact at the interface of middle reflector of TCO and semiconductor layer to series resistance.But well-known, the ZnO layer is not easy to form ohmic contact at the interface with noncrystalline silicon layer or crystalloid silicon layer.More particularly, if the dark conductivity in reflector is lower than 1.0 * 10 in the middle of the ZnO ²S/cm, then this reflector, centre and the place ahead photoelectric conversion units between and and the rear photoelectric conversion units between can not form good Ohmic contact, and contact resistance is increased, the curve factor (FF) of stacked photoelectric converter is reduced.On the contrary, the dark conductivity as the ZnO layer is higher than 1.0 * 10 ³S/cm then makes its light transmission rate reduce, and the short-circuit current density (Jsc) of stacked photoelectric converter is reduced.Therefore, need or regulate oxidizability etc. by impurity the dark conductivity of tco layer is set in higher 1.0 * 10 ²S/cm～1.0 * 10 ³In the scope of S/cm.

But large-area film photoelectric converting means is made as integrated thin film light-to-current inversion module usually.Integrated thin film light-to-current inversion module has the structure that a plurality of components of photo-electric conversion that are divided into small size of being connected in series mutually form on a slice glass substrate.Usually, each components of photo-electric conversion on glass substrate by order carry out transparent electrode layer, more than one thin film semiconductor photoelectric conversion units layer, and the film forming and the composition of backplate layer form.

Figure 30 shows that with schematic cross sectional view there is one of existing integrated thin film light-to-current inversion module that the lamination type in the middle reflector components of photo-electric conversion form example a plurality of not the conforming to that be connected in series.In addition, identical reference marks is represented same section or considerable part in the application's the accompanying drawing.This light-to-current inversion module 101 has on glass substrate 102 sequential laminating transparent electrode layer 103, the place ahead uncrystalline silicon photovoltaic element layer 104a, rear crystalloid silicon photoelectric conversion units layer 104b, and the structure that forms of backplate layer 106.

On integrated thin film light-to-current inversion module 101, be provided with the link slot 123 that is used for electric mutually first and second separating tanks 121,122 that separate of a plurality of components of photo-electric conversion 110 and is used for these element connected in series are electrically connected.First and second separating tanks 121,122 and link slot 123 are parallel to each other, and vertically extend with respect to the paper of Figure 30.That is, first separating tank, 121 corresponding each components of photo-electric conversion 110 are separated into a plurality of zones with transparent electrode layer 103.Also corresponding each components of photo-electric conversion 110 of second separating tank 122 are separated into a plurality of zones with the place ahead photoelectric conversion units layer 104a, rear photoelectric conversion units layer 104b and backplate layer 106.

The link slot of being located between first separating tank 121 and second separating tank 122 123 connects the place ahead photoelectric conversion units layer 104a and rear photoelectric conversion units layer 104b.This link slot 123 is electrically connected in series one of the adjacent components of photo-electric conversion 110 person's backplate 106 and another person's transparency electrode 103 by imbedding with backplate layer 106 identical metal material.

It is different that the integrated thin film light-to-current inversion module of Figure 31 only is between the place ahead light-to-current inversion module 104a and the rear light-to-current inversion module 104b to insert in the middle of the TCO on 105 this point of reflector the module with Figure 30.In the light-to-current inversion module of Figure 31, link slot 123 connects middle reflector 105 of the place ahead photoelectric conversion units layer 104a, TCO and rear photoelectric conversion units layer 104b, by imbedding with backplate layer 106 identical metal material.That is, the metal material of imbedding link slot 123 is contacted with reflector 105 in the middle of the TCO.

As previously mentioned, reflector 105 has 1.0 * 10 in the middle of the TCO ²S/cm～1.0 * 10 ³The high dark conductivity of S/cm, in this tco layer 105 along the direction parallel also inflow current easily with substrate 102.Therefore, because the current path of reflector 105, link slot 123 and backplate 106 causes rear photoelectric conversion units 104b short circuit in the middle of the TCO, produce big leakage current.Its result almost can not take out the electric power that is produced by rear photoelectric conversion units 104b in the light-to-current inversion module of Figure 31.

Conventional example 1

The problem of such leakage current can solve (1 spy opens the 2002-261308 communique with reference to patent documentation) by adopting structure shown in Figure 32.That is, on the integrated thin film light-to-current inversion module 101 of Figure 32, on the basis of first and second separating tanks 121,122, between first separating tank 121 and link slot 123, also be provided with the 3rd separating tank 124.The 3rd separating tank 124 connects the place ahead light-to-current inversion module 104a and middle reflector 105.In addition, the 3rd separating tank 124 can be configured such that also first separating tank 121 is between the 3rd separating tank 124 and link slot 123.But, shown in figure 32, the 3rd separating tank is set between first separating tank 121 and link slot 123 the generating effective area is increased.

Owing in the light-to-current inversion module 101 of Figure 32, be provided with the 3rd separating tank 124, be situated between by reflector 105 in the middle of the TCO and link slot 123 leakages so can prevent the generation electric current of the place ahead photoelectric conversion units 104a.But the light-to-current inversion module of Figure 32 is compared with the module of Figure 30, has added the 3rd separating tank 124.First～the 3rd separating tank and link slot are usually by being formed by compositions such as YAG laser.That is, the light-to-current inversion module of Figure 32 is compared with the module of Figure 31, has increased the operation of a composition, has produced the problem that its manufacturing cost and time increase.

In addition, when making the light-to-current inversion module of Figure 30, can in plasma CVD apparatus, form the place ahead photoelectric conversion units 104a and rear photoelectric conversion units 104b continuously.But, when making the light-to-current inversion module of Figure 32, utilizing plasma CVD to form the place ahead photoelectric conversion units 104a, and, substrate taken out from vacuum plant by behind the reflector 105 in the middle of the formation TCO such as sputter, utilize YAG laser to carry out composition.Then, once more substrate is imported in the vacuum plant, utilize plasma CVD to form rear photoelectric conversion units 104b.Therefore, the light-to-current inversion module of Figure 32 and the module of Figure 30 are compared, and also have the problem that manufacturing time and cost increase.

In addition, owing in the middle of forming TCO, behind the reflector 105 substrate is fetched in the atmosphere, so can adsorb the impurity in the atmosphere at the interface of middle reflector 105 and rear photoelectric conversion units 104b, the characteristic that produces the light-to-current inversion module sometimes reduces or film such as is stripped from the problem that reliability reduces.

In addition, owing to increase the area consumption of film photoelectric inverting elements, the characteristic that reflector 105, TCO centre obtains is set in the light-to-current inversion module improves effect so can not give full play to sometimes by the 3rd separating tank 124 is set.

Conventional example 2

In stacked photoelectric converter, the material of a conductive layer uses the example of amorphous silicon oxide to be disclosed in patent documentation 2 spies and opens in the flat 5-95126 communique.In this stacked photoelectric converter, sequential laminating SnO on glass substrate ₂Etc. the 2nd n type layer of the 2nd i type layer of the 2nd p type layer of a n type layer of an i type layer of a p type layer of transparency electrode, noncrystalline carbonization silicon, uncrystalline silicon, amorphous silicon oxide, noncrystalline carbonization silicon, uncrystalline silicon, uncrystalline silicon, and metal electrode such as Ag.A common n type layer uses uncrystalline silicon or microcrystal silicon, but has reported in the patent documentation 2 and can reduce the absorption loss of light by using the wide amorphous silicon oxide of band gap.Its result represents that the light that arrives the 2nd i type layer in the photoelectric conversion units of rear through the n type layer in the photoelectric conversion units of the place ahead increases, and the short-circuit current density of stacked photoelectric converter (Jse) improves.

The oxygen concentration of amorphous silicon oxide layer can be adjusted arbitrarily, and oxygen concentration is high more, and its band gap is wide more, and transmitance is high more.On the other hand, in the amorphous silicon oxide layer, its oxygen concentration is high more, and conductivity is low more.Patent documentation 2 reports: in a n type layer of amorphous silicon oxide, the conductivity photoconductivity during irradiates light need be 1.0 * 10 ^-6More than the S/cm, therefore, by general formula a-Si _1-xO _xDuring the expression amorphous silicon oxide, need make x less than 0.2.

In patent documentation 2, by increasing the light that arrives the 2nd i type layer, increase the generation current of rear photoelectric conversion units, increase the Jsc of lamination type film photoelectric converting means, improve conversion efficiency.But, in patent documentation 2, to the submission of the generation current of the place ahead photoelectric conversion units without any explanation.In patent documentation 2,, so as shown in Figure 5, we can say that the refractive index to this amorphous silicon oxide film of light of wavelength 600nm is equal to or greater than about 3 because the oxygen concentration of amorphous silicon oxide film is restricted to and is less than 20%.At this moment, because the refringence between amorphous silicon oxide layer and the noncrystalline silicon layer is little, so can not expect by the electric current of reflecting effect increase the place ahead photoelectric conversion units at interface at them.For the amorphous silicon oxide layer is worked as middle reflector, must increase its oxygen concentration, reduce refractive index, but the photoconductivity of amorphous silicon oxide layer reduce in this case, so can think that the FF of stacked photoelectric converter reduces, conversion efficiency reduces.Therefore, the amorphous silicon oxide layer does not use as middle reflector in the patent documentation 2.

Patent documentation 1: the spy opens the 2002-261308 communique

Patent documentation 2: the spy opens flat 5-95126 communique

As mentioned above, in stacked photoelectric converter, when tco layers such as middle reflector use ZnO, compare with semiconductor layer, because the formation method difference of TCO so need be provided for forming the device or the film forming room of tco layer in addition, has the problem that can not avoid installation cost to raise.Specifically, utilize plasma CVD to form with respect to semiconductor layer, the reflector is by formation such as sputtering method or spray-on processes in the middle of the TCO.

In addition, when using tco layer to make integrated thin film light-to-current inversion module, in structure, has the generation leakage current, the problem that the characteristic of this light-to-current inversion module is low with first separating tank, second separating tank and link slot in middle reflector.

The problem of this leakage current can solve by the 3rd separating tank 124 is set shown in figure 32, but owing to will increase composition one time, so produce the problem of production cost and time increase.In addition, the interface of middle reflector and rear light-to-current inversion module might be contaminated because of being exposed to atmosphere.In addition, because the 3rd separating tank is set, can produce the problem of the area consumption increase in effective light-to-current inversion zone.

Summary of the invention

This present invention develops in view of above such prior art, its purpose is, a kind of lamination type film photoelectric converting means and integrated thin film light-to-current inversion module are provided, and it has prevented to make needed cost and the time increases, and has improved light-to-current inversion efficient.

In the stacked photoelectric converter of the present invention, on substrate from light incident side sequential laminating one conductive layer, the light-to-current inversion layer of intrinsic semiconductor and contain a plurality of photoelectric conversion units of reverse conductive layer in fact, be disposed at relatively in the place ahead photoelectric conversion units of light incident side reverse conductive layer and in the conductive layer in the rear photoelectric conversion units of this place ahead photoelectric conversion units configuration at least one at least its part have the silicon composite bed, this silicon composite bed has the thickness of 20nm～130nm and the oxygen concentration of 25 atom %～60 atom %, contains Si-rich phase at the amorphous alloy of silicon and oxygen in mutually.In addition, the Si-rich phase in the present specification is described as its literal, is meant the silicon concentration height.Therefore, Si-rich phase is meant the phase that the part silicon concentration is high.

The silicon composite bed preferably has the oxygen concentration of 40 atom %～55 atom % for realizing low refractive index.In addition, be made as 20nm～130nm, can produce effective reflecting effect by thickness with the silicon composite bed.For obtaining optimum reflecting effect, the silicon composite bed preferably has the thickness of 50nm～100nm.

That is, by increasing the oxygen concentration of silicon composite bed, realize low refractive index, the high reflecting effect at the interface of the semiconductor layer that can obtain and be adjacent.In addition, although the oxygen concentration height of silicon composite bed can be realized high dark conductivity by containing Si-rich phase.Consequently can high reflecting effect and high dark conductivity be realized simultaneously, can increase the generation current of the place ahead photoelectric conversion units, improve the performance of stacked photoelectric converter by utilizing the silicon composite bed.

Si-rich phase preferably contains the silicon crystal phase.The thickness direction of considering the silicon composite bed exists the current path that is situated between by the silicon crystal phase to enumerate as the reason that can form good Ohmic contact.Replace, Si-rich phase preferably also contains the uncrystalline silicon of doping.As everyone knows, as fully being doped with impurity, then n type and p type uncrystalline silicon all can obtain being enough to form the low resistive film of ohmic contact.

The silicon composite bed is for obtaining sufficient reflecting effect, and the refractive index of the light of wavelength 600nm is preferably 1.7～2.5, and more preferably 1.8～2.1.At the substrate of stacked photoelectric converter when being transparent, the reflection of light spectrum that arrives the silicon composite bed by this transparent substrates contains the maximum and the minimum of at least one reflectivity respectively in the scope of wavelength 500nm～800nm, these maximum and minimizing difference are preferably and are equal to or greater than 1%.

The silicon composite bed preferably has 10 ^-8S/cm～10 ^-1The dark conductivity of S/cm.Low excessively as this dark conductivity, then the curve factor (FF) of stacked photoelectric converter reduces, and conversion efficiency is low.On the contrary, too high as dark conductivity, then be formed in the reason that produces leakage current in the film photoelectric conversion module that integrated a plurality of lamination type components of photo-electric conversion form.The silicon composite bed is for realizing optimum dark conductivity, and the TO pattern peak value of crystalline silicon component is preferably 0.5～10 with respect to the strength ratio of the pattern peak value of the TO (optics lateral vibration) of the uncrystalline silicon component of Raman scattering mensuration.In addition, the dopant atom concentration in the silicon composite bed preferably is positioned at 3 * 10 ²⁰～1.8 * 10 ²¹Cm ^-3Scope in.

The silicon composite bed is for obtaining sufficient reflecting effect, and its optical gap is preferably and is equal to or greater than 2.2eV.In addition, be subjected to utilizing the difference of the photoelectronic the top energy of interband excitation loss of the Ols that the X linear light electron spectroscopy for chemical analysis of silicon composite bed measures and the photoelectronic peak energy of Ols to be preferably and be equal to or greater than 2.2eV.

In integrated-type light-to-current inversion module of the present invention, first electrode layer of sequential laminating on substrate, a plurality of photoelectric conversion units layers, and the second electrode lay is separated by a plurality of separating tanks, form a plurality of components of photo-electric conversion, and these elements are situated between and are electrically connected in series mutually by a plurality of link slots, in each components of photo-electric conversion, one conductive layer is arranged from the light incident side sequential laminating, the light-to-current inversion layer of the intrinsic semiconductor of essence, and contain a plurality of photoelectric conversion units of reverse conductive layer, be disposed at comparatively speaking in the place ahead photoelectric conversion units of light incident side reverse conductive layer and in the conductive layer in the rear photoelectric conversion units of this place ahead photoelectric conversion units configuration at least one at least its part have the silicon composite bed, this silicon composite bed has the thickness of 20nm～130nm and the oxygen concentration of 25 atom %～60 atom %, contains Si-rich phase at the amorphous alloy of silicon and oxygen in mutually.

In addition, first electrode layer is separated into a plurality of zones of corresponding a plurality of components of photo-electric conversion by a plurality of first separating tanks, a plurality of photoelectric conversion units layers and the second electrode lay are separated into a plurality of zones of corresponding a plurality of elements by a plurality of second separating tanks, are used to be electrically connected first electrode of the element that adjoins each other and the link slot of second electrode and are preferably disposed between first separating tank and second separating tank.

When making stacked photoelectric converter, the mixing ratio of the silicon unstrpped gas of doped raw material gas when piling up the silicon composite bed in the plasma CVD reative cell is preferably in 0.012～0.07 the scope.In addition, when making stacked photoelectric converter, after also can in the plasma CVD reative cell, being stacked into the part of integral thickness of silicon composite bed, temporarily be fetched into substrate in the atmosphere, the surface of silicon composite bed is exposed in the atmosphere, then, substrate is imported in the plasma CVD reative cell, pile up the remainder of the integral thickness of silicon composite bed.At this moment, be preferably in pile up silicon composite bed integral thickness more than 60% after, substrate is fetched into the atmosphere in the plasma CVD reative cell.

In stacked photoelectric converter of the present invention, since at the interface incident light of silicon composite bed and the semiconductor layer that joins with it by partial reflection, so the generation current of the place ahead photoelectric conversion units is increased, or compare with the situation that does not contain the silicon composite bed, even the thickness of the light-to-current inversion layer of attenuate the place ahead photoelectric conversion units also can produce equal electric current.

In addition, because silicon composite bed and photoelectric conversion units can utilize plasma CVD to form equally, so can utilize identical plasma CVD apparatus to make the place ahead photoelectric conversion units, silicon composite bed, reach the rear photoelectric conversion units.Therefore, do not need the equipment of the alternate manner of the middle reflector of the existing TCO of being used for film forming, production cost and the time that can reduce stacked photoelectric converter.

In integrated-type light-to-current inversion module of the present invention, because the silicon composite bed has higher dark conductivity in the direction parallel with face, so do not need the composition of the 3rd separating tank in the middle reflector of existing separation TCO, can reduce production costs and in the time, avoid resulting from the reduction of the light-to-current inversion efficient that the loss of the power generation region of the 3rd separating tank causes.

Description of drawings

Fig. 1 is the curve that shows about the relation of the refractive index of the silicon composite bed of the light of wavelength 600nm and dark conductivity;

Fig. 2 is the photo that shows one of the dark field image utilize the silicon composite bed that the infiltration type electron microscope method obtains example;

Fig. 3 is the photo that shows one of the high image resolution utilize the silicon composite bed that the infiltration type electron microscope method obtains example;

Fig. 4 is the curve of one of the raman scattering spectrum of demonstration silicon composite bed example;

Fig. 5 shows the oxygen concentration of silicon composite bed and with respect to the curve of the relation of the refractive index of the light of wavelength 600nm;

Fig. 6 is the curve that shows the relation of the optical gap of silicon composite bed and absorption spectrum;

Fig. 7 is the curve that shows the relation of the refractive index of light of wavelength 600nm of silicon composite bed and optical gap;

Fig. 8 is the curve that is presented at the energy of photoelectron loss spectrum of the Ols that utilizes X linear light electron spectroscopy for chemical analysis mensuration in the silicon composite bed;

Fig. 9 is the photoelectron curve of the energy difference of energy and the photoelectronic peak energy of Ols topmost that the refractive index to the light of wavelength 600nm is presented at the interband excitation loss that is subjected to utilizing the Ols that X linear light electron spectroscopy for chemical analysis measures in the silicon composite bed;

Figure 10 is the schematic cross sectional view that shows the stacked photoelectric converter of one embodiment of the invention;

Figure 11 shows the thickness of silicon composite bed and the curve of the relation of the reflectivity at the interface of having considered to disturb;

Figure 12 is the photo that shows one of the bright field image example of the section utilize the stacked photoelectric converter of the present invention that the infiltration type electron microscopy obtains;

Figure 13 is the photo that shows the dark field image corresponding with Figure 12;

Figure 14 is the curve that is presented in the stacked photoelectric converter of the present invention from the reflection of light rate of glass lined bottom side incident;

Figure 15 is the schematic cross sectional view that shows the stacked photoelectric converter of one of prior art example;

Figure 16 is the schematic cross sectional view that shows another routine stacked photoelectric converter of prior art;

Figure 17 is the schematic cross sectional view that shows the stacked photoelectric converter of other embodiment of the present invention;

Figure 18 is the schematic cross sectional view that shows the stacked photoelectric converter of other embodiment of the present invention;

Figure 19 is the schematic cross sectional view that shows the stacked photoelectric converter of other embodiment of the present invention;

Figure 20 is the curve that shows the faradic relative value of spectrum in the stacked photoelectric converter of the present invention;

Figure 21 is the schematic cross sectional view that shows the stacked photoelectric converter of other embodiment of the present invention;

Figure 22 is the schematic cross sectional view that shows the stacked photoelectric converter of other embodiment of the present invention;

Figure 23 is the schematic cross sectional view that shows the stacked photoelectric converter of other embodiment of the present invention;

Figure 24 is the schematic cross sectional view that shows the stacked photoelectric converter of other embodiment of the present invention;

Figure 25 is the schematic cross sectional view that shows three sections stacked photoelectric converters of other embodiment of the present invention;

Figure 26 is the schematic cross sectional view of one of three sections stacked photoelectric converters of demonstration prior art example;

Figure 27 is the schematic cross sectional view that shows three sections stacked photoelectric converters of other embodiment of the present invention;

Figure 28 is the schematic cross sectional view that shows three sections stacked photoelectric converters of other embodiment of the present invention;

Figure 29 is the schematic cross sectional view that shows the integrated-type light-to-current inversion module of other embodiment of the present invention;

Figure 30 is the schematic cross sectional view of one of the lamination type light-to-current inversion module of demonstration prior art example;

Figure 31 is other the routine schematic cross sectional view of integrated-type light-to-current inversion module that shows prior art;

Figure 32 is other the routine schematic cross sectional view of integrated-type light-to-current inversion module that shows prior art;

Figure 33 shows curve based on the distribution of the phosphorus concentration of SIMS and oxygen concentration about the stacked photoelectric converter of one embodiment of the invention;

Figure 34 shows curve based on the distribution of the oxygen concentration of XPS about the stacked photoelectric converter of other embodiment of the present invention;

Figure 35 is other the routine curve that shows the raman scattering spectrum of silicon composite bed.

Symbol description

1 glass substrate

2 transparent electrode layers

3 the place ahead photoelectric conversion units

3a first photoelectric conversion units

4 n type silicon composite beds

5 rear photoelectric conversion units

5a second photoelectric conversion units

6 backplate layers

7 n type silicon composite beds

8 the 3rd photoelectric conversion units

31 p type noncrystalline carbonization silicon layers

32,32a i type noncrystalline silicon layer

33 n type microcrystal silicon layers

33a n type silicon composite bed

33b, 33c n type microcrystal silicon layer

34 n type silicon composite beds

35 n type microcrystal silicon layers

36 n type microcrystal silicon layers

37 n type silicon composite beds

38 n type microcrystal silicon layers

39 n type amorphous silicon oxide layers

51 p type microcrystal silicon layers

51a p type silicon composite bed

51b, 51c p type microcrystal silicon layer

52,52a i type crystalloid silicon layer

53 n type microcrystal silicon layers

53a n type silicon composite bed

53b, 53c n type microcrystal silicon layer

81 p type microcrystal silicon layers

81a p type silicon composite bed

82 i type crystalloid silicon layers

83 n type microcrystal silicon layers

101 integrated thin film light-to-current inversion modules

102 glass substrate

103 transparent electrode layers

104a the place ahead photoelectric conversion units

104b rear photoelectric conversion units

Reflector in the middle of 105 TCO

106 backplate layers

107 silicon composite beds

110 components of photo-electric conversion

121 first separating tanks

122 second separating tanks

123 link slots

124 the 3rd separating tanks

Embodiment

The present inventor finds out the material that has low-refraction and high conductivity concurrently, has inquired into deeply based on the silicon of high frequency plasma CVD and the alloy forming method of oxygen.It found that the layer (being called the silicon composite bed among the application) that contains Si-rich phase in mutually at the amorphous alloy of silicon and oxygen can have low refractive index and high conductivity concurrently.

The refractive index that the silicon composite bed of film forming on glass substrate is measured and the relation of dark conductivity have been shown in the curve of Fig. 1.At this, refractive index uses beam split analysis of polarized light determination method that the light of wavelength 600nm is measured.The reason of selecting the wavelength of 600nm be because, in a kind of hybrid optical electric conversion means as stacked photoelectric converter, near the wavelength of the faradic rising of spectrum 600nm of faradic decline of the spectrum of noncrystalline photoelectric conversion units and crystalloid photoelectric conversion units is staggered.Promptly little with respect to the optical index of the wavelength 600nm film of film that reflects near the light of the wavelength the 600nm well is suitable for making the generation current near the noncrystalline photoelectric conversion units in the place ahead of light incident side to increase.

Dark conductivity is measured with the electric current that flows along the direction parallel with substrate by on the silicon composite bed on the substrate coplanar electrodes being set.As shown in Figure 1, the present inventor finds can realize simultaneously 1.7～2.5 low refractive index and 10 by detailed result of the test in the silicon composite bed ^-8～10 ^-1The higher dark conductivity of S/cm.Because to the uncrystalline silicon of the light of wavelength 600m or the refractive index of crystalloid silicon is about 4, so the difference of the refractive index of silicon composite bed and silicon layer is big, can obtain sufficient reflecting effect.

A preferred embodiment has the situation that Si-rich phase contains the silicon crystal phase as the silicon composite bed.Fig. 2 is a silicon composite bed of extracting film forming on glass substrate out, shows from the dark field image of the infiltration type electron microscope method of taking perpendicular to the direction of face (TEM).The dark field image is the reflection that obtains at the electronics line that specific crystal face reflects.That is, do not produce refraction in the noncrystalline part, and only comprise the crystal generation refraction that constitutes the crystal face of specific Larger bragg angles with respect to the electronics line.Therefore, must show the crystal phase in the zone of the distinct imaging of dark field image.That is, Fig. 2 shows and contains the crystal phase in the noncrystalline.Fig. 3 is from take the image of the high image resolution TEM that the composite bed identical with Fig. 2 obtain perpendicular to the direction of face.Can confirm to arrange the subregion of well-regulated lattice, in film, contain the crystal phase as can be known.

The raman scattering spectrum of the silicon composite bed of curve representation Fig. 2 of Fig. 4.In this chart at 520cm ^-1Near present the spike of the TO pattern of crystalline silicon.That is, the Si-rich phase in the silicon composite bed contains silicon crystal as can be known.At this moment, 480cm ^-1Near the strength ratio of the TO pattern peak value of the relative uncrystalline silicon component of TO pattern peak value of crystalline silicon component is 2.5.

The silicon composite bed that can make low-refraction and high dark conductivity and deposit can be formed by following plasma CVD as can be known by test, uses SiH as reacting gas ₄, CO ₂, H ₂And PH ₃(or B ₂H ₆), the big H that is creating conditions as microcrystalline coating ₂/ SiH ₄On the basis of ratio, with CO ₂/ SiH ₂In the scope that is set in 2～10 degree.At this moment, the condition of plasma generation can adopt capacitive junctions mould assembly parallel plate electrode, the supply frequency of 10～100MHz, 50～500mW/cm ²Pressure, and 150～250 ℃ the underlayer temperature of power density, 50～1000Pa.As increase CO ₂/ SiH ₄Ratio, then the oxygen concentration of silicon composite bed is dull increases.But, by test as can be known, even make CO ₂/ SiH ₄Than changing in 0～4 scope, the concentration of carbon of silicon composite bed also is equal to or less than 1 atom %, and carbon is compared with oxygen, imports in the film hardly.

The oxygen concentration of the curve display silicon composite bed of Fig. 5 and to the relation of the refractive index of the light of wavelength 600nm.With reference to Figure 20, as described later the refractive index of silicon composite bed is made as and is less than or equal to 2.5, increase the output current of stacked photoelectric converter with the reflecting effect that utilizes the silicon composite bed, for this reason, as can be seen from Figure 5, be equal to or greater than 25 atom % as long as oxygen concentration is made as.In addition, refractive index is made as is equal to or less than 2.1, be equal to or greater than 10% output current (with reference to Figure 20), for this reason, be equal to or greater than 40 atom % (with reference to Fig. 5) as long as oxygen concentration is made as to utilize the reflecting effect increase.

The dark conductivity of silicon composite bed is by the oxygen concentration in its layer, impurity (P or B) concentration, and the ratio decision of silicon crystal phase.For the dark conductivity with the silicon composite bed is adjusted into 10 ^-8～10 ^-1S/cm, and refractive index is adjusted into 1.7～2.5, oxygen concentration is preferably 25～60 atom %.That is, because along with the increase of the oxygen concentration of silicon composite bed, refractive index reduces, but dark conductivity also reduces, so there is the desirable upper limit in the oxygen concentration of silicon composite bed.

When adopting n type silicon composite bed, preferably will be made as 5 * 10 as the P concentration of impurity ¹⁹/ cm ^-3～2 * 10 ²²/ cm ^-3And when adopting p type silicon composite bed, preferably will be made as 5 * 10 as the B concentration of impurity ¹⁹/ cm ^-3～2 * 10 ²¹/ cm ^-3Though along with the dark conductivity of the increase silicon composite bed of P concentration or B concentration increases, as the impurity surplus, the then ratio of crystal phase minimizing, therefore, the dark conductivity of silicon composite bed reduces on the contrary.Therefore, P concentration or B concentration preferably are adjusted in the above-mentioned scope.

In addition, as the index of the silicon crystal phase ratio in the silicon composite bed, the TO pattern peak value of the crystalline silicon component of measuring by Raman scattering is preferably 0.5～10 with respect to the strength ratio of the TO pattern peak value of uncrystalline silicon component.Along with the increase of this peak strength ratio, the dark conductivity of silicon composite bed increases, but as peak strength than excessive, then the ratio of the amorphous silicon oxide in the silicon composite bed reduces, the refractive index increase.Therefore, the peak strength of Raman scattering is than preferably being adjusted into above-mentioned scope.

In the curve of Fig. 1, even under the identical refractive index of silicon composite bed, dark conductivity also can produce deviation, this be because oxygen concentration, impurity concentration, and the ratio condition changing of silicon crystal phase cause.

In silicon composite bed of the present invention,,, also can keep the dark conductivity of film thickness direction than the highland so, refractive index is reduced to below 2.5 even improve oxygen concentration owing to consider to have the effect of the movement route of electronics at the film thickness direction Si-rich phase.Therefore, even this silicon composite bed is configured between the place ahead photoelectric conversion units and rear photoelectric conversion units of stacked photoelectric converter, photo-electric conversion device is also very little to the influence of series resistance, can design to have the thickness that is suitable for light restriction most and the silicon composite bed of refractive index.And, because the refractive index of silicon composite bed only changes CO ₂/ SiH ₄Gas is adjusted oxygen concentration and just can easily be controlled, so by make refractive index cycle variation etc. can expect the increase of the light restriction effect that meticulousr optical design obtains at film thickness direction.

Be the harmful effect of the series resistance that suppresses to give stacked photoelectric converter, by the such TCO of ZnO constitute existing in the middle of the dark conductivity in reflector be necessary for 10 ²～10 ³This very high value of S/cm.As everyone knows, be difficult to usually form ohmic contact at the interface of ZnO and uncrystalline silicon or crystalloid silicon.Particularly be difficult to form ohmic contact at the interface of ZnO and p type uncrystalline silicon or p type crystalloid silicon.But, know that by detailed discussion the silicon composite bed is as having 10 ^-8～10 ^-1The dark conductivity of S/cm then can realize good Ohmic contact between the silicon photoelectric conversion units of itself and noncrystalline and crystalloid.As one of this reason is that silicon composite bed and uncrystalline silicon and crystalloid silicon are to be the semiconductive thin film of main component with silicon equally.

In addition, consider to exist current path to can be used as the reason that can form good Ohmic contact via the silicon crystal phase at the thickness direction of silicon composite bed.The dark conductivity of Fig. 1 is the value of obtaining from the electric current that flows into the direction parallel with face, but electric current is mobile along the thickness direction of silicon composite bed in stacked photoelectric converter.In the TEM of Fig. 2 dark field image, disperse to have distinct visible crystal phase, we can say that the silicon crystal of the full depth that connects the silicon composite bed is equal to be scattered here and there planarly.Therefore, in the silicon composite bed that imports stacked photoelectric converter, even it is low to be parallel to the dark conductivity of direction of face, electric current also can mainly be situated between and be flowed by the silicon crystal thickness direction that hands down, and its result can suppress the increase of the series resistance of stacked photoelectric converter.

The light energy (E) that the curve display of Fig. 6 is inversely proportional to silicon composite bed and optical wavelength and the relation of absorption coefficient (α).In this curve, a plurality of curve a～g correspondence has a plurality of different silicon composite bed of different optical gaps.Energy gap in the optical gap reflection silicon composite bed.The relative light energy of optical gap (E) is marked and drawed curve

, the energy that the axle of the extended line conduct of its straight line portion and α=0 intersects is obtained (( ウスプロ Star ト) obtains optical gap from so-called Tao Si curve).

In the curve of Fig. 6, along with the increase of the optical gap of silicon composite bed, curve jumps to the right or down, and when being compared by identical light energy, absorption coefficient is index to be reduced.That is, when the silicon composite bed being used for the reflector, centre,, then can being index ground and reducing absorption loss water as its optical gap is increased.Be equivalent to above-mentioned conventional example 2 in the situation of 2.05eV of scope of desirable optical gap compare, as optical gap is made as more than the 2.2eV, then in wide light energy scope, absorption coefficient can be reduced to below 1/3.That is,, can reduce the absorption loss water of stacked photoelectric converter being in the middle of silicon composite bed more than the 2.2eV is applied to during the reflector with optical gap.

The curve representation of Fig. 7 is about the refractive index of the light of silicon composite bed wavelength 600nm and the relation of optical gap.As shown in Figure 7, along with the attenuating of refractive index, optical gap increases, and particularly refractive index significantly increases less than 2.2 o'clock optical gaps.Wide as optical gap, then the absorption loss water of silicon composite bed generation reduces, and therefore, is desirable to the characteristic that improves stacked photoelectric converter.That is, less than 2.2, the reduction effect of the absorption loss water that then reflecting effect not only, and the increase of optical gap produces is also remarkable as the refractive index of silicon composite bed, can improve the characteristic of stacked photoelectric converter.

When piling up the silicon composite bed of the above thickness of 300nm on glass substrate, its optical gap can be easily from seeing through spectrum or obtaining from seeing through spectrum and reflectance spectrum.But, be difficult to measure optical gap when thickness is thin or to the part of the thickness direction of laminated film.Therefore and optical gap same, as the index of the energy gap of reflection silicon composite bed, carried out the mensuration of X linear light electron spectroscopy for chemical analysis (XPS).The energy of photoelectron loss spectrum that the curve representation of Fig. 8 utilizes X linear light electron spectroscopy for chemical analysis to measure about the silicon composite bed.

In Fig. 8,, the photoelectronic the top energy of the interband excitation loss that is subjected to Ols and the energy difference (being called Exps) of the photoelectronic peak energy of Ols have been obtained as the index of the energy gap of silicon composite bed.X linear light electron spectroscopy for chemical analysis also is called for short XPS or ESCA.The kernel photoelectron that roentgen radiation x is produced on sample have do not lose the energy when producing and deviate from the vacuum detected and in film, deviate from behind the off-energy deviate from the vacuum detected.Main energy loss in the film have that interband excitation causes excitation produces with phasmon.Under the situation of silicon composite bed, compare with the interband excitation, very big because phasmon is actuated to 20eV, so can be with its Signal Separation.Prolonging the line part of the SPECTRAL REGION comprise interband excitation loss, serves as the upper end energy with the intersection point of itself and baseline, obtains the poor of itself and Ols peak energy as Exps.In the example of Fig. 8, Exps is 3.4eV.Even XPS also can measure the film below the 10nm.In addition, as the top layer that utilizes ion sputtering to remove striping, carry out XPS simultaneously and measure, then also can obtain Exps curve about the depth direction of film.Therefore, according to XPS, can carry out Exps mensuration to film below the 10nm and the random layer in the stacked photoelectric converter.

The curve representation of Fig. 9 is about the refractive index of the light of silicon composite bed wavelength 600nm and the relation of Exps.Shown in this curve, be reduced to below 2.2 as refractive index, then Exps sharply increases.That is, in stacked photoelectric converter, the refractive index that make its silicon composite bed increases electric current with the reflecting effect that utilizes the silicon composite bed, as long as Exps is made as more than the 2.2eV less than 2.2.In addition, not only reflecting effect for reducing the absorption loss water of silicon composite bed, also preferably makes refractive index less than 2.2.

As mentioned above, in the middle of using existing TCO during the reflector, suppress to give the harmful effect of the series resistance of stacked photoelectric converter, its dark conductivity is necessary for higher value 10 ²～10 ³S/cm.But, distinguish by detailed discussion, although the silicon composite bed has low dark conductivity in the direction parallel with face, between the photoelectric conversion units of itself and uncrystalline silicon and crystalloid silicon, can realize good Ohmic contact.

Even also can form good Ohmic contact because the dark conductivity of silicon composite bed is compared low order bit～10 with TCO, thus can be with the simplifying the structure of integrated-type light-to-current inversion module, can seek the raising of conversion efficiency of module and the reduction of cost.That is, in integrated thin film light-to-current inversion module, even do not contain the structure of the 3rd separating tank 124 shown in Figure 32, also can not produce the problem of leakage current, this point is detailed later.Therefore, in integrated-type light-to-current inversion module, composition be can reduce one time, manufacturing cost and time decreased made.In addition, owing to can omit the 3rd separating tank 124,, can improve the conversion efficiency of integrated-type light-to-current inversion module so the area consumption in light-to-current inversion zone reduces.

As other desirable embodiment of silicon composite bed, existence can not detect the situation of silicon crystal phase in Si-rich phase.That is, exist Si-rich phase to contain the situation of uncrystalline silicon.

In addition, the term of " noncrystalline " in the present specification is meant the state that can not detect the crystal phase.Whether contain silicon crystal in the silicon composite bed and also exist with ... the plasma CVD condition mutually.The inventor confirms that even contain under the situation of uncrystalline silicon utilizing known analytical method can not detect the silicon crystal phase in the silicon composite bed, in the middle of this silicon composite bed also can be used as sometimes effectively work in the reflector.Like this, although the silicon composite bed does not contain detectable crystal phase, consider following situation (1)-(4) as its reason that also can effectively work in the middle reflector of stacked photoelectric converter.

(1) can be situated between mutually or the non-detectable low-density crystal film thickness direction conveying electronic that hands down by non-detectable small crystal in the silicon composite bed.

(2) can be situated between by the part of the Silicon-rich in the silicon composite bed along the film thickness direction conveying electronic.As everyone knows, as abundant impurity, then the dark conductivity of n type uncrystalline silicon is higher value 10 ^-3S/cm～10 ^-1S/cm, the dark conductivity of p type uncrystalline silicon is higher value 10 ^-5S/cm～10 ^-2S/cm.

(3) be about to generate under the state of crystal phase front, in the silicon composite bed, producing the presoma of crystallization.The local generation tiny area lower than common noncrystalline resistance can be along the film thickness direction conveying electronic.Under for the situation of utilizing the silicon based thin film that plasma CVD piles up, as producing the crystal phase, then this crystal film thickness direction column of handing down is grown up, and this is well-known.Therefore, even will generate the noncrystalline of crystal phase front, at film thickness direction low-resistance tiny area of also can growing up, electronics moves to this direction easily.

(4) can form good Ohmic contact by the silicon composite bed that does not contain the crystal phase, this is because the silicon composite bed is identical with uncrystalline silicon and crystalloid silicon, is the semiconductor film based on silicon.

By the way, when containing uncrystalline silicon, when carrying out the mensuration of Raman scattering, because at 480cm as Si-rich phase ^-1Near present the TO pattern peak value of uncrystalline silicon, so can easily confirm.

Figure 10 schematically shows the profile of the stacked photoelectric converter of one embodiment of the invention.In this stacked photoelectric converter, on as the glass substrate 1 of transparent substrates the silicon composite bed 4 of sequential laminating transparent electrode layer 2, uncrystalline silicon photoelectric conversion units, a conductivity type (p type or n type) as first photoelectric conversion units 3, as the crystalloid silicon photoelectric conversion units of second photoelectric conversion units 5, and backplate layer 6.In addition, a conduction type silicon composite bed 4 shows as the layer of the arbitrary unit that does not belong to first photoelectric conversion units 3 and second photoelectric conversion units 5 among Figure 10, but also can be thought of as the part of conductivity type (p type or the n type) layer of a certain unit that is contained in first photoelectric conversion units 3 and second photoelectric conversion units 5.

Transparent substrates also can be used transparent resin film etc. except that glass, but for seeing through to the light-to-current inversion layer and absorbing more sunlight, preferably uses the high as far as possible material of transparency.With same intention, reduce for making reflection loss of light at the substrate surface of sunlight incident, be preferably formed as the areflexia coating.

Transparent electrode layer 2 can use tin oxide (SnO ₂), indium tin oxide (ITO), zinc oxide transparent conductive oxides (TCO) such as (ZnO), but especially preferably use SnO ₂In addition, the interface that is preferably in transparent electrode layer 2 and photoelectric conversion units 3 forms has the concavo-convex of 200～900nm average headway, therefore, is preferably formed as the transparent electrode layer 2 of 200～900nm average grain diameter.

In addition, lamination has two sections photoelectric conversion units in Figure 10, but as described below, can certainly lamination more than three sections.In addition, when the photoelectric conversion units of lamination more than three sections, the silicon composite bed 4 of insertion can be one deck, also can insert between all possible photoelectric conversion units.

Photoelectric conversion units contains a conductive layer, the semi-conductive i type of reality light-to-current inversion layer, and reverse conductive layer in fact.One conductive layer both can be p type layer, also can be n type layer, and was corresponding, and oppositely conductive layer is n type layer or p type layer.But, in photo-electric conversion device, at the light incident side configuration p of light type layer, so in the structure of Figure 10, a common

conductive layer

31,51 is a P type layer, oppositely

conductive layer

33,53 is a n type layer usually.I type

layer

32,52 is used for absorbing light and carries out light-to-current inversion, therefore they are preferably the different mutually combination of band gap, are light absorption wavelength zone different combination of materials mutually, and preferably (400nm～1200nm) has absorption to the dominant wavelength territory of sunlight as stacked photoelectric converter integral body.For example, be preferably the combination etc. of combination, i type noncrystalline silicon layer and the i type crystalloid silicon layer of i type noncrystalline silicon layer and i type uncrystalline silicon germanium layer.

When forming the amorphous silicon thin-film photoelectric conversion units, also can carry out lamination with the order of nip layer, consider, preferably with the sequential laminating of pin layer from the viewpoint that obtains higher conversion efficiency by plasma CVD as the unit photoelectric conversion units 3 in the place ahead among Figure 10.At this moment, as long as pile up the p type noncrystalline carbonization silicon layer 31 that the boron of foreign atom as the decision conductivity type that for example mixes more than the 0.01 atom % forms, the i type noncrystalline silicon layer 32 that constitutes the light-to-current inversion layer, and the n type microcrystal silicon layer 33 that forms of the phosphorus more than the 0.01 atom % of mixing in proper order as the foreign atom of decision conductivity type with this.But these layers are not limited thereto, and for example also can use uncrystalline silicon, microcrystal silicon or uncrystalline silicon nitride as p type layer.In addition, also can use uncrystalline silicon as n type layer.Preferred 3nm～the 100nm of thickness of conductivity type (p type or n type) layer, more preferably 5nm～50nm.

The part that will arrive the light on it as the silicon composite bed 4 of an important feature of the present invention makes in the remaining light transmission rear photoelectric conversion units 5 to the place ahead photoelectric conversion units 3 incidents that are positioned at light incident side.When the light-to-current inversion layer uses the silicon based material, because the refractive index of this light-to-current inversion layer of light of wavelength 600nm is about 4, so the refractive index of silicon composite bed 4 is preferably in 1.7～2.5 the scope.In addition, because being situated between, electric current flows, so the dark conductivity of silicon composite bed 4 is preferably 10 by silicon composite bed 4 ^-8S/cm～10 ^-1S/cm.

The thickness of the curve representation silicon composite bed 4 of Figure 11 and considered the relation of reflection of light rate of the wavelength 600nm of the interference between its two sides.At this moment, the silicon composite bed is 2 to the refractive index of the light of wavelength 600nm.By this curve as can be known, the light of photoelectric conversion units 3 reflections forwards is decided to be more than 10%, preferably the thickness with silicon composite bed 4 is set at 20nm～130nm.In addition, the light of photoelectric conversion units 3 reflections forwards is decided to be more than 30%, preferably the thickness with silicon composite bed 4 is set at 50nm～100nm.

The place ahead photoelectric conversion units 3, silicon composite bed 4, and rear photoelectric conversion units 5 preferably be not fetched in the atmosphere, but form continuously.At this, be not fetched into and mean in the atmosphere and maintain the environment that can prevent surface contamination, for realizing this point, can use known the whole bag of tricks.

Like this, structure and the thickness that is applicable to the silicon composite bed 4 of stacked photoelectric converter can be resolved by infiltration type electron microscope method (TEM).Figure 12 is the bright field TEM image that obtains according to the section of taking the photograph near the thickness direction the silicon composite bed in the stacked photoelectric converter of the structure with glass substrate/transparent electrode layer/noncrystalline photoelectric conversion units/silicon composite bed/crystalloid photoelectric conversion units/backplate layer.The density of reflection silicon composite bed (μ c-SiO) is lower than the density of the noncrystalline silicon layer (a-Si) of its both sides and crystalloid silicon layer (poly-Si) in the bright field image of Figure 12, and the part of silicon composite bed is taken to such an extent that turn white.Figure 13 is the dark field image that obtains according to the bright field image same position of taking the photograph with Figure 12.In this dark field image, have the small bright part that is scattered in the silicon composite bed, in the silicon composite bed, contain small crystal phase as can be known.

The oxygen concentration of the silicon composite bed in the stacked photoelectric converter, P concentration or B concentration can detect by known analytical method.For example can be after the backplate layer of stacked photoelectric converter be removed in acid such as utilizing HCl, remove the top layer by utilizing Wet-type etching, plasma etching, ion sputtering etc., make the change in depth of measuring the zone, utilize SIMS (secondary ion mass spectrometry with halogen labeling), ESCA (PES), EPMA (the little laser resolver of X line), Auger electron optical spectroscopy etc. analyses to form simultaneously.

In addition, the refractive index of the silicon composite bed in the stacked photoelectric converter can be exposed by making this silicon composite bed, is measured by the analysis of polarized light determination method and detects.In addition, the judgement that has or not the silicon composite bed is by just detecting easily from difference of the reflection of light rate of glass substrate incident etc.The curve of Figure 14 is to be illustrated in the stacked photoelectric converter of the silicon composite bed that contains 60nm or 30nm thickness and not contain in the stacked photoelectric converter of silicon composite bed from the curve of the reflection of light spectrum of glass substrate incident.When containing the silicon composite bed, light interreflection in the noncrystalline photoelectric conversion units produces and interferes, and the difference that shows reflectivity is that maximum and the minimum more than 1% occurs in the scope of wavelength 500nm～800nm.On the contrary, when not containing the silicon composite bed, there are not clear and definite maximum and minimum in this wavelength region may.

In the stacked photoelectric converter of Figure 10, when on silicon composite bed 4, for example forming crystalloid silicon photoelectric conversion units, preferably also form with the low base reservoir temperature below 400 ℃ by plasma CVD with the order of pin layer as second photoelectric conversion units 5.That is, the crystalloid silicon as i type light-to-current inversion layer 52 is that the light-to-current inversion layer is because formation at low temperatures constitutes the hydrogen atom that terminal makes its deactivation thereby preferably contain the defective that makes boundary or grain or intragranular in a large number.Specifically, the hydrogen content of i type light-to-current inversion layer 52 is preferably in the scope of 1～15 atom %.In addition, this i type layer is 1 * 10 as the density of the foreign atom that determines conductivity type preferably ¹⁸Cm ^-3The film of following essence intrinsic semiconductor forms.

In addition, many preferred the extensions along roughly vertical with its face direction column of crystal grain that are contained in the i type crystal silicon layer 52 grow up, and have the preferred orientation face of parallel with face (110).This be because, even have such crystalline orientation crystalloid silicon thin film transparency electrode 2 above come down to smoothly, pile up and also to show the surface crazing structure that contains micro concavo-convex above the photoelectric conversion units 5 thereon.Therefore, on transparency electrode 2, have when comprising concavo-convex reticulate structure, therefore the concavo-convex overlapping reticulate structure of the fine concavo-convex and transparency electrode 2 of generation on photoelectric conversion units 5, obtains being applicable to the big reticulate structure of light restriction effect of light of the wavelength region may of reflection wide region.In addition, the thickness of i type crystalloid silicon layer is preferably 0.1 μ m～10 μ m.But, (400～1200nm) have absorption, are that noncrystalline SiGe (for example containing the following germanium of 30 atom %) layer or crystalloid germanium-silicon layer replace i type crystalloid silicon layer so also can form alloy material owing to preferred dominant wavelength zone to sunlight as the film photoelectric converter unit.

But the thickness of the p type crystalloid silicon layer 51 in the crystalloid silicon photoelectric conversion units 4 is preferably in the scope of 3nm～25nm.That is, during less than 3nm, can not produce is enough to and will be fetched into outside internal electric field at the i type crystalloid silicon light-to-current inversion layer 52 inner charge carrier that produces by rayed at the thickness of p type crystalloid silicon layer 51.At its thickness during greater than 25nm, the optical absorption loss of p type layer 51 itself increase.The situation of the thickness of n type crystalloid silicon 53 and p type crystalloid silicon is similar, is preferably in the scope of 3nm～20nm.

As backplate layer 6, preferably form and contain the metal level of one deck at least at least a among Al, Ag, Au, Cu, Pt and the Cr by sputtering method or vapour deposition method.In addition, also can between photoelectric conversion units 5 and metal electrode 6, form ITO, SnO ₂, tco layer (not shown) such as ZnO.

For example, backplate 6 preferably formation form the multilayer film of the silverskin of the ZnO film of 10nm～150nm thickness and 30nm～500nm thickness in proper order.When ZnO film was thinner than 10nm, the tack of crystalloid silicon photoelectric conversion units 5 and silverskin 6 worsened, and on the contrary, when being thicker than 150nm, the light absorption of ZnO film itself increases, and constituted the main cause of the characteristic reduction of photo-electric conversion device.The effect of silverskin 6 is that reflection is difficult to the light by the long wavelength side of crystalloid silicon photoelectric conversion units 5 absorptions, and makes it incide this photoelectric conversion units 5 once more.At the thickness of silverskin 6 is 30nm when following, swashs as the effect in reflector and reduces sharply for a short time, be 500nm when above, the manufacturing cost increase.

In the example of Figure 10, used transparent substrates 1, even but on opaque substrate the stacked photoelectric converter of sequential laminating backplate layer, rear photoelectric conversion units, silicon composite bed, the place ahead photoelectric conversion units, transparent electrode layer, the generation current of the place ahead photoelectric conversion units is increased, improve conversion efficiency.But, at this moment, rear photoelectric conversion units and the place ahead photoelectric conversion units are preferably all carried out lamination from substrate side with the order of nip type layer.

The following describes the comparative example such as the embodiments of the invention of prior art.In addition, use identical symbol with a part or suitable part in the application's the accompanying drawing, the repetitive description thereof will be omitted.

At first, about two sections stacked photoelectric converter, the comparative example 1,2 and the embodiments of the invention 1～4 of prior art are described.Table 1 gathers the characteristic of the stacked photoelectric converter that shows these comparative examples 1,2 and embodiment 1～4.The effective area of each photo-electric conversion device is 1cm ², with 100mW/1cm ²The light of light quantity irradiation AM1.5, measure output characteristic down at 25 ℃.The open circuit voltage (Voc), short-circuit current density (Jsc), the curve factor (FF) of each photo-electric conversion device of expression in the table 1, and conversion efficiency (Eff).The output current of the place ahead photoelectric conversion units of obtaining by the spectral response spectroscopic assay in the table 1 in addition,, the output current of rear photoelectric conversion units, and the output current of integral body that they are comprehensive also represent by being worth standardized relative value with these of comparative example 1.

	The n type layer of the place ahead photoelectric conversion units	Middle reflector	Voc (V)	??Jsc ??(mA/cm ²)	?FF	?Eff ?(％)	Spectrum induced current (with the comparative example standardization)
										The place ahead photoelectric conversion units	The rear photoelectric conversion units	Whole
							Comparative example 1	Microcrystal silicon	-	The place ahead photoelectric conversion units	The rear photoelectric conversion units	Whole	1.353	??11.61	?0.734	?11.53	1.00	????1.00	??1.00
Comparative example 2	Amorphous silicon oxide	-	1.354	??11.64	?0.730	?11.51	Comparative example 1	Microcrystal silicon	-	0.99	????1.01	??1.00	1.353	??11.61	?0.734	?11.53	1.00	????1.00	??1.00
Comparative example 2	Amorphous silicon oxide	-	1.354	??11.64	?0.730	?11.51	Embodiment 1	Microcrystal silicon	N type silicon composite bed	0.99	????1.01	??1.00	1.338	??12.71	?0.701	?11.92	1.09	????1.06	??1.08
Embodiment 2	The silicon composite bed	-	1.340	??13.29	?0.692	?12.32	Embodiment 1	Microcrystal silicon	N type silicon composite bed	1.14	????1.15	??1.14	1.338	??12.71	?0.701	?11.92	1.09	????1.06	??1.08
Embodiment 2	The silicon composite bed	-	1.340	??13.29	?0.692	?12.32	Embodiment 3	Silicon composite bed/microcrystal silicon	-	1.14	????1.15	??1.14	1.346	??13.04	?0.721	?12.65	1.12	????1.08	??1.12
Embodiment 4	Microcrystal silicon/silicon composite bed/microcrystal silicon	-	1.350	??12.96	?0.732	?12.80	Embodiment 3	Silicon composite bed/microcrystal silicon	-	1.07	????1.11	??1.10	1.346	??13.04	?0.721	?12.65	1.12	????1.08	??1.12

Comparative example 1

As a comparative example 1, made stacked photoelectric converter shown in Figure 15.At first, at thickness 1.1mm, utilize the hot CVD method to form the SnO that contains small taper concave-convex surface and average thickness 800nm on the square glass substrate 1 of 127mm ₂Film is as transparent electrode layer 2.The pellet resistance of the transparent electrode layer 2 that obtains is about about 9 Ω/.In addition, this rate of visiing of measuring with illuminant-C is 12%, and the average difference of height d of concave-convex surface is about 100nm.On this transparent electrode layer 2, utilize plasma CVD to form to contain i type noncrystalline silicon layer 32, and the place ahead photoelectric conversion units 3 of the n type microcrystal silicon layer 33 of thickness 30nm of p type noncrystalline carbonization silicon layer 31, the thickness 0.3 μ m of thickness 15nm, then, order forms i type crystalloid silicon layer 52, and the rear photoelectric conversion units 5 of the n type microcrystal silicon layer 53 of thickness 15nm of the p type microcrystal silicon layer 51 contain thickness 15nm, thickness 2.5 μ m.Then, utilize sputtering method to form the Ag film of the ZnO film of doped with Al of thickness 90nm and thickness 300nm in proper order as backplate 6.

Comparative example 2

As a comparative example 2, made stacked photoelectric converter shown in Figure 16.The device of this comparative example shown in Figure 16 2 is only different with the device of comparative example 1 on n type microcrystal silicon layer 33 this point of being replaced among Figure 15 by the n type amorphous silicon oxide layer 39 of thickness 30nm.In addition, the device of this comparative example 2 except that with the rear photoelectric conversion units as the crystalloid photoelectric conversion units, have and the similar structure of device of above-mentioned in advance example 2.The membrance casting condition of n type amorphous silicon oxide layer 39 is gas flow SiH ₄/ CO ₂/ PH ₃/ H ₂=5/2.5/0.1/100sccm, supply frequency number are 13.56MHz, and power density is 20mW/cm ², pressure is 100Pa, underlayer temperature is 200 ℃.In the amorphous silicon oxide layer 39 that forms, oxygen concentration is 18 atom %, refractive index to the light of wavelength 600nm is 3.0, the TO pattern peak value of the crystalline silicon composition that Raman scattering is measured is 0 with respect to the strength ratio of the TO pattern peak value of uncrystalline silicon composition, do not have the crystal phase, dark conductivity is 1.2 * 10 ^-6S/cm.

As shown in Table 1, the characteristic that comparative example 2 shows and comparative example 1 is roughly the same does not show the variation to the amount of having meaning on the spectrum induced current of the increase of Jsc or the place ahead photoelectric conversion units.Thus, oxygen concentration is that the n type amorphous silicon oxide layer 39 of 18 atom % we can say there is not the effect of photoelectric conversion units 3 lateral reflection light forwards.That is, the refractive index height of this n type amorphous silicon oxide layer 39 is 3.0, and is little with noncrystalline silicon layer and crystalloid silicon layer refringence relatively, so almost can not obtain the reflecting effect based on n type amorphous silicon oxide layer 39.

Embodiment 1

As embodiment 1, made stacked photoelectric converter shown in Figure 10.The device of this embodiment 1 is photoelectric conversion units 3 and extensively form in the middle of the photoelectric conversion units 5 on n type silicon composite bed 4 this point of thickness 30nm different with the device of comparative example 1 shown in Figure 15 forwardly only.In addition, this n type silicon composite bed 4 also can consider to be contained in the part of the n type layer of the place ahead photoelectric conversion units 3.

The membrance casting condition of n type silicon composite bed 4 is that gas flow ratio is SiH ₄/ CO ₂/ PH ₃/ H ₂=5/10/0.1/1000sccm, supply frequency is 13.56MHz, power density is 100mW/cm ², pressure is 100Pa, underlayer temperature is 200 ℃.In the n type silicon composite bed 4 that forms, oxygen concentration is 42 atom %, optical gap is 2.37eV, the Exps that is measured by XPS is 3.5eV, refractive index to the light of wavelength 600nm is 2.0, the TO pattern peak value of the crystalline silicon composition that Raman scattering is measured is 2.0 with respect to the strength ratio of the TO pattern peak value of uncrystalline silicon composition, and dark conductivity is 5 * 10 ^-6S/cm.

As shown in Table 1, embodiment 1 compares with comparative example 1, though FF reduces a little, Jsc increases 1mA/cm ²More than, Eff improves.In addition, the spectrum induced current of the place ahead photoelectric conversion units increases by 9%, and silicon composite bed 4 reflexes to the place ahead photoelectric conversion units side effectively with incident light.In addition, in embodiment 1, the spectrum induced current of rear photoelectric conversion units also increases by 6%, produces light scattering by utilizing silicon composite bed 4, and the optical path length in the photoelectric conversion units of rear has also extended.

Embodiment 2

As embodiment 2, made stacked photoelectric converter shown in Figure 17.The device of this embodiment 2 is only different with the device of embodiment 1 shown in Figure 10 on reflector and the n type layer this point in the middle of the n type silicon composite bed 4 by used thickness 30nm is also used as the n type layer of the place ahead photoelectric conversion units 3.

As shown in Table 1, present embodiment 2 is compared with embodiment 1, and Jsc further increases, and Eff improves, and the spectrum induced current of the place ahead photoelectric conversion units and rear photoelectric conversion units also increases.This be because, by by the silicon composite bed 4 double n type layers of doing the place ahead photoelectric conversion units 3, thereby forwards the light of photoelectric conversion units 3 lateral reflections and the light that sees through rear converter unit 5 sides needn't all pass through the n type microcrystal silicon layer of thickness 30nm, make the absorption loss minimizing.But, comparing with comparative example 1 and embodiment 1, FF reduces among the embodiment 2, and at the interface of i type noncrystalline silicon layer 32 and silicon composite bed 4, contact resistance increases.

The phosphorus concentration that the graphical representation of Figure 33 is measured by SIMS along the thickness direction of the photo-electric conversion device of the laminated structure with Figure 17 and the distribution of oxygen concentration.That is, the transverse axis of this curve chart is represented the distance of thickness direction (μ m), and the left longitudinal axis is represented atomic concentration (cm ^-3), the right longitudinal axis is represented the counting (c/s) of SIMS per second.Backplate 6 is given earlier by the Wet-type etching that adopts hydrochloric acid to carry out and being removed, and carries out ion sputtering towards substrate 1 side, simultaneously, utilizes SIMS to measure phosphorus concentration and oxygen concentration along depth direction (thickness direction).Shown in the curve of Figure 33, owing to have clear and definite peak value at depth direction identical position phosphorus and oxygen, so there is n type silicon composite bed as can be known.

The distribution of the oxygen concentration that the graphical representation of Figure 34 is measured by XPS along the thickness direction of the photo-electric conversion device of the laminated structure with Figure 17.That is, the transverse axis of this curve chart represent the sputtering time of thickness direction (minute), the longitudinal axis is represented atom %.In addition, the thickness of the silicon composite bed that comprises in the stacked photoelectric converter that XPS measures is 50nm, and its refractive index is 2.18.Backplate 6 is given earlier by the Wet-type etching that adopts hydrochloric acid to carry out and being removed, and carries out ion sputtering towards substrate 1 side, simultaneously, utilizes XPS to measure oxygen concentration along depth direction (thickness direction).Shown in the curve of Figure 34, oxygen concentration presents clear and definite peak value, has the silicon composite bed as can be known.The peak value of oxygen concentration is about 15 atom % in this curve chart, and its width between half-power points is about 110nm.The thickness of considering actual silicon composite bed is 50nm, because (15 atom %) * (110nm/50nm)=33, so the oxygen concentration of the silicon composite bed of XPS mensuration is 33 atom % as can be known.

Embodiment 3

As embodiment 3, made stacked photoelectric converter shown in Figure 180.The device of this embodiment 3 only in lamination as different on the n type silicon composite bed 34 of the thickness 30nm of a n type layer and the n type layer this point that forms the place ahead photoelectric conversion units 3 as the n type microcrystal silicon layer 35 of the thickness 5nm of the 2nd n type layer with the device of embodiment 2 shown in Figure 17.Certainly, the n type silicon composite bed 34 of present embodiment 3 also with the n type silicon composite bed 4 of

embodiment

1 and 2 with identical plasma CVD condition film forming.

As shown in Table 1, present embodiment 3 is compared with embodiment 2, though Jsc reduces slightly, FF raises, and Eff raises.In addition, though the spectrum induced current of the place ahead photoelectric conversion units of present embodiment 3 is lower slightly than embodiment 2, than comparative example 1 and embodiment 1 height.At this moment because insertion n type microcrystal silicon layer 35 has reduced the contact resistance at n/p interface between n type silicon composite bed 34 and p type microcrystal silicon layer 51, has improved FF.In addition, because the thickness of the n type microcrystal silicon layer 35 that inserts in present embodiment 3 is 5nm, very thin, so compare with embodiment 2, the reduction of Jsc is little.

Embodiment 4

As embodiment 4, made stacked photoelectric converter shown in Figure 19.The device of this embodiment 4 only lamination as the n type microcrystal silicon layer 36 of the thickness 10nm of a n type layer with as different on the n type silicon composite bed 37 of the thickness 60nm of the 2nd n type layer and the n type layer this point that forms the place ahead photoelectric conversion units 3 as the n type microcrystal silicon layer 38 of the thickness 5nm of the 3rd n type layer with the device of embodiment 2 shown in Figure 17.

As shown in Table 1, present embodiment 4 is compared with embodiment 3, and Jsc reduces slightly, but FF raises the Eff rising.This be because, between i type noncrystalline silicon layer 32 and n type silicon composite bed 37, insert n type microcrystal silicon layer 36 contact resistance at i/n interface also reduced, compare with embodiment 3, FF further improves.In addition, in the present embodiment 4, because n type microcrystal silicon layer 36 except that n type silicon composite bed 37 and n type microcrystal silicon layer 38 have the little thickness that adds up to 15nm, and thinner than the thickness 30nm of the n type microcrystal silicon layer 33 under the situation of embodiment 1, so absorption loss water reduces, Jsc compares also with embodiment 1 have been increased.

Embodiment 5

As embodiment 5, the faradic relative value of spectrum the when graphical representation of Figure 20 makes the variations in refractive index of the silicon composite bed 4 in the stacked photoelectric converter of the structure with Figure 17.Silicon composite bed 4 in the present embodiment 5 removes and make CO in plasma CVD ₂/ SiH ₄Ratio in 1～15 scope, change outside and

embodiment

1 and 2 same film forming.Transverse axis is represented the refractive index of the light of 4 couples of wavelength 600nm of silicon composite bed in this curve chart, and the longitudinal axis represents to compare with the comparative example 1 of the Figure 15 that does not contain the silicon composite bed the faradic relative value of spectrum of the device of present embodiment 5.

As shown in figure 20, the spectrum induced current of the place ahead photoelectric conversion units 3 reduces with the refractive index of silicon composite bed 4 and increases, as refractive index less than about 1.8 minimizings.Can followingly consider as this reason, when the refractive index of silicon composite bed 4 reduces, the light that reflexes to the place ahead photoelectric conversion units 3 sides increases, the spectrum induced current increases, if but refractive index is less than about 1.8, then the dark conductivity of silicon composite bed 4 reduces, thereby can not ignore the influence that the contact resistance at the resistance of silicon composite bed 4 and interface increases, and electric current reduces.

The spectrum induced current of rear photoelectric conversion units 5 increases along with the minimizing of the refractive index of silicon composite bed 4, if refractive index less than about 2, then reduces.Because when refractive index reduced, the transmitance of silicon composite bed 4 increased, increase so arrive the light of rear photoelectric conversion units 5, its electric current increases.Approximately less than 2, then the light of photoelectric conversion units side 3 reflections forwards increases as the refractive index of silicon composite bed 4, thereby can not ignore the influence that the light that arrives rear photoelectric conversion units 5 reduces, and its electric current reduces.

As shown in Figure 20, the spectrum induced current of the integral body of comprehensive the place ahead photoelectric conversion units 3 and rear photoelectric conversion units 5 also has the maximum of the refractive index of existing with ....In the refractive index of silicon composite bed 4 more than or equal to 1.7 less than 2.5 o'clock, compare with comparative example 1, the spectrum induced current of the stacked photoelectric converter integral body of present embodiment 5 increases.In addition, compare,, then need the refractive index of silicon composite bed 4 is set at 1.8～2.1 for the spectrum induced current of the stacked photoelectric converter integral body that makes present embodiment 5 increases more than 10% with the situation of comparative example 1.

Secondly, just in two sections stacked photoelectric converters, the situation of silicon composite bed is also used in the part of a conductive layer of photoelectric conversion units (p layer) in the wings, and the comparative example 1 and the embodiments of the invention 6～9 of prior art are described.The relative value of the characteristic of these stacked photoelectric converters gathers and is shown in the table 2.

Table 2

	The formation of the n type layer of the place ahead photoelectric conversion units	The formation of the p type layer of rear photoelectric conversion units	Output characteristic (with comparative example 1 standardization)
							????Voc	????Jsc	????FF	????Eff
			Comparative example 1	Microcrystal silicon	Microcrystal silicon	????1.00	????Voc	????Jsc	????FF	????Eff	????1.00	????1.00	????1.00
Embodiment 6	Microcrystal silicon	The silicon composite bed	Comparative example 1	Microcrystal silicon	Microcrystal silicon	????1.00	????1.00	????1.09	????0.96	????1.04	????1.00	????1.00	????1.00
Embodiment 6	Microcrystal silicon	The silicon composite bed	Embodiment 7	The silicon composite bed	The silicon composite bed	????1.00	????1.00	????1.09	????0.96	????1.04	????1.20	????0.93	????1.11
Embodiment 8	Microcrystal silicon/silicon composite bed	Silicon composite bed/microcrystal silicon	Embodiment 7	The silicon composite bed	The silicon composite bed	????1.00	????0.99	????1.17	????0.97	????1.12	????1.20	????0.93	????1.11
Embodiment 8	Microcrystal silicon/silicon composite bed	Silicon composite bed/microcrystal silicon	Embodiment 9	Silicon composite bed/microcrystal silicon	Microcrystal silicon/silicon composite bed	????0.99	????0.99	????1.17	????0.97	????1.12	????1.14	????0.98	????1.12

Embodiment 6

In embodiment 6, made stacked photoelectric converter shown in Figure 21.The device of this embodiment 6 is only different with the device of comparative example 1 shown in Figure 15 on the p type layer this point of being replaced rear photoelectric conversion units 5 by the p type silicon composite bed 51a of thickness 30nm.

The plasma CVD condition of P type silicon composite bed 51a is that gas flow ratio is SiH ₄/ CO ₂/ B ₂H ₆/ H ₂=1/2/0.0025/500, supply frequency is 13.56MHz, and power density is 100mW/cm ², pressure is 800Pa, underlayer temperature is 200 ℃.In the p type silicon composite bed 51a that obtains, oxygen concentration is 29 atom %, refractive index to the light of wavelength 600nm is 2.45, and the TO pattern peak value of the crystalline silicon composition that Raman scattering is measured is 1.2 with respect to the strength ratio of the TO pattern peak value of uncrystalline silicon composition, and dark conductivity is 2 * 10 ^-5S/cm.

As shown in table 2, in embodiment 6, compare with comparative example 1, Jsc also increases, and Eff also improves.P type silicon composite bed 51a works as middle reflector, and incident light is reflexed to the place ahead photoelectric conversion units 3 sides effectively.In addition, because the p type layer of rear photoelectric conversion units 5 replaces with the high p type silicon composite bed 51a of transparency, so optical absorption loss also reduces.But, in present embodiment 6, compare with comparative example 1, FF reduces, and increases at the interface of n type microcrystal silicon layer 33/p type silicon composite bed 51a or the interface contact resistance of p type silicon composite bed 51a/i type crystalloid silicon layer 52.

Embodiment 7

In embodiment 7, made stacked photoelectric converter shown in Figure 22.The device of this embodiment 7 is only being replaced the n type layer of the place ahead photoelectric conversion units 3 by the n type silicon composite bed 33a of thickness 30nm, and is replaced on the p type layer this point of rear photoelectric conversion units 5 different with the device of comparative example 1 shown in Figure 15 by the p type silicon composite bed 51a of thickness 30nm.In addition, the plasma CVD condition film forming identical that n type silicon composite bed 33a utilizes with the n type silicon composite bed of embodiment 1 and 24.

As shown in Table 2, embodiment 7 compares with comparative example 1, and Jsc significantly increases, and Eff raises.Even compare with embodiment 6, Jsc also increases, and Eff also increases.Its reason considers that the aggregate thickness of n type silicon composite bed 33a and p type silicon composite bed 51a is 60nm, and they further improve as the function in middle reflector.In addition and since the p type layer of the n type layer of the place ahead photoelectric conversion units 3 and rear photoelectric conversion units 5 both all replace with the high silicon composite bed of transparency, so also significantly reduction of optical absorption loss.But, compare with comparative example 1, FF reduces in embodiment 7, increases at the interface of i type noncrystalline silicon layer 32/ silicon composite bed 33a or the interface contact resistance of p type silicon composite bed 51a/i type crystalloid silicon layer 52.

Embodiment 8

In embodiment 8, made stacked photoelectric converter shown in Figure 23.The device of this embodiment 8 is only at the n type silicon composite bed 33a of the n type microcrystal silicon layer 33b of sequential laminating thickness 10nm and the thickness 30nm n type layer 22 as the place ahead photoelectric conversion units 3, and the p type microcrystal silicon 51b of the p type silicon composite bed 51a of sequential laminating thickness 30nm and thickness 5nm is as different with the device of embodiment 7 shown in Figure 22 on p type layer 51 this point of rear photoelectric conversion units 5.

As shown in table 2, embodiment 8 compares with embodiment 7, and FF improves.Its reason can be considered, the contact resistance at i type noncrystalline silicon layer 32/n type silicon composite bed 33a interface reduces by clipping thin n type microcrystal silicon layer 33b, and the contact resistance at p type silicon composite bed 51a/i type crystalloid silicon layer 52 interfaces reduces by clipping thin p type microcrystal silicon layer 51b.On the other hand, because the influence of the optical absorption loss of n type microcrystal silicon layer 33b and p type microcrystal silicon layer 51b, Jsc is lower slightly than the Jsc of embodiment 7 in the present embodiment 8.

Embodiment 9

In embodiment 9, made stacked photoelectric converter shown in Figure 24.The device of this embodiment 9 is only at the n type microcrystal silicon layer 33c of the n type silicon composite bed 33a of sequential laminating thickness 30nm and the thickness 10nm n type layer 33 as the place ahead photoelectric conversion units 3, and the p type silicon composite bed 51a of the p type microcrystal silicon 51b of sequential laminating thickness 5nm and thickness 30nm is as different with the device of embodiment 8 shown in Figure 23 on p type layer 51 this point of rear photoelectric conversion units 5.

As shown in table 2, embodiment 9 compares with embodiment 8, and FF improves.Its reason can consider be because, the place ahead photoelectric conversion units 3 that shows the most significantly in the influence of contact resistance and the joint interface of rear photoelectric conversion units 5 are not situated between the silicon composite bed are arranged, and and the comparative example 1 of Figure 15 similarly form the joint of n type microcrystal silicon layer 33c/p type microcrystal silicon layer 51c.

Embodiment 10

In embodiment 10, similar to Example 2, made stacked photoelectric converter shown in Figure 17.The device of this embodiment 10 only changes to 50nm at the thickness with the n type silicon composite bed 4 of the place ahead photoelectric conversion units 3, and is simultaneously, different with the device of embodiment 2 on its plasma CVD condition changing this point.That is, other of the device of present embodiment 10 created conditions identical with the situation of comparative example 1 and embodiment 2.

Specifically, the condition of the plasma CVD of the n type silicon composite bed 4 of present embodiment 10 is that gas flow ratio is SiH ₄/ CO ₂/ PH ₃/ H ₂=1/3/0.02/100, supply frequency is 13.56MHz, and power density is 100mW/cm ², pressure is 100Pa, underlayer temperature is 200 ℃.In present embodiment 10, different with the situation of comparative example 2, with H ₂Relative SiH ₄Dilution factor be elevated to 100 times, if this do not contain CO ₂, then be the condition that occurs the crystal phase easily.In the n type silicon composite bed 4 that utilizes this condition to obtain, oxygen concentration is 44 atom %, and optical gap is 2.42eV, and the Exps that is measured by XPS is 3.6eV, and dark conductivity is 1.2 * 10 ^-12S/cm is 1.95 to the refractive index of the light of wavelength 600nm, obtains the low refractive index that is equal to mutually with tco layer.In addition, in this silicon composite bed, measure the TO pattern peak value that detects non-crystalline silicon by carrying out Raman scattering, uncrystalline silicon is contained in the affirmation part.But, when carrying out the mensuration of this Raman scattering, do not detect the TO pattern peak value of crystalline silicon, that is, be 0 with respect to strength ratio (Ic/Ia) based on the TO pattern peak value of amorphous alloy phase based on the TO pattern peak value of crystalline silicon phase, do not detect the silicon crystal phase.In addition, in the silicon composite bed of present embodiment 10, utilize X-ray diffraction and infiltration type electron microscope method also not to detect the crystal phase.

Utilize relative value to represent the characteristic of the stacked photoelectric converter of comparative example 1 and present embodiment 10 in the table 3.As shown in Table 3,, also can increase Jsc, improve Eff even, compare with comparative example 1 as the shaping photo-electric conversion device of present embodiment 10, having under the situation of the silicon composite bed that does not contain the silicon crystal phase.In addition, compare with comparative example 1, the spectrum induced current of first photoelectric conversion units 3 and second photoelectric conversion units 5 all increases in the present embodiment 10.Hence one can see that, and silicon composite bed 4 works as middle reflector, effectively incident light reflexed to first photoelectric conversion units, 3 sides.In addition, can consider to produce scattering of light at silicon composite bed 4, the optical path length in second photoelectric conversion units 5 has also extended.In addition, because the n type layer of unit photoelectric conversion units 3 is replaced with the high silicon composite bed 4 of transparency, so optical absorption loss also reduces.But, present embodiment 10 is compared with comparative example 1, and FF reduces, and increases at the interface of i type noncrystalline silicon layer 32/ silicon composite bed 4 or the interface contact resistance of silicon composite bed 4/p type microcrystal silicon 51.

Table 3

	The structure of the n type layer of the place ahead photoelectric conversion units	Output characteristic (with comparative example 1 standardization)
						??Voc	??Jsc	??FF	??Eff
		Comparative example 1	Microcrystal silicon	??1.00	??1.00	??Voc	??Jsc	??FF	??Eff	??1.00	??1.00
Embodiment 10	The silicon composite bed	Comparative example 1	Microcrystal silicon	??1.00	??1.00	??0.99	??1.16	??0.95	??1.09	??1.00	??1.00

Embodiment 11

Figure 35 is the curve chart of the raman scattering spectrum of the expression determining film thickness that changes the silicon composite bed.The situation of the silicon composite bed among the plasma CVD condition of the silicon composite bed of the embodiment 11 in this curve chart, reference example 1 and reference example 2 and the embodiment 10 is identical.In present embodiment 11, remove the backplate 6 of the stacked photoelectric converter of embodiment 10 by Wet-type etching, by ion sputtering the surface of silicon composite bed 4 is exposed, measured raman scattering spectrum.At this moment, the thickness of silicon composite bed 4 is 50nm.In reference example 1 and reference example 2, on glass substrate, pile up the silicon composite bed of 300nm and 1 μ m thickness respectively.

Thickness at the silicon composite bed is respectively among the embodiment 11 and reference example 1 of 50nm and 300nm, is illustrated in 480cm among Figure 35 ^-1Near only observe the wide TO pattern peak value of width of amorphous silicon components, do not contain crystalline phase in the film.On the other hand, be in the reference example 2 of 1 μ m at the thickness of silicon composite bed, in the curve of Figure 35 at 520cm ^-1Near observe shoulder, detect TO pattern peak value based on the crystalline silicon composition.

As shown in figure 35, because if thickening silicon composite bed then detects the crystal phase, so the state that the silicon composite bed of embodiment 11 constitutes the crystal phase will produce the time.That is, the silicon composite bed in the stacked photoelectric converter contains silicon crystal and can be described as one of better condition mutually at the thickness of piling up under the identical plasma CVD condition more than the 1 μ m.In addition, about the silicon composite bed of embodiment 11 and reference example 1, do not detect the crystal phase with X-ray diffraction and infiltration type electron microscope method.

Comparing with embodiment 11, only change the hydrogen dilution rate, when piling up the silicon composite bed, be to detect crystalline phase in the silicon composite bed that obtains more than 120 with the hydrogen dilution rate.In addition, in the photo-electric conversion device of the laminated structure with embodiment 11, when the hydrogen dilution rate when only making the accumulation of silicon composite bed 4 changed in 50～120, the hydrogen dilution rate was 70 to compare with comparative example 1 when above, and Jsc increases more than 5%.That is, in stacked photoelectric converter, the hydrogen dilution rate when the silicon composite bed in reflector is piled up in the middle of being used for is made as one of the desirable condition that can be described as more than 60% of the hydrogen dilution rate when detecting crystalline phase.In addition, even by the plasma CVD condition that in the silicon composite bed, generates crystalline phase the membrance casting condition beyond the hydrogen dilution rate is moved and the silicon composite bed piled up to the amorphous condition lateral deviation of easy generation, also can improve the characteristic of stacked photoelectric converter effectively.

Embodiment 12

The schematic cross sectional view of Figure 25 has shown three sections stacked photoelectric converters of embodiment 12.In this photo-electric conversion device, until second section photoelectric conversion units 5a, except that the thickness of i type layer changes and the situation of the embodiment 1 of Figure 10 similarly make.The thickness of the i type noncrystalline silicon layer 32a of first section photoelectric conversion units 3a is 100nm among Figure 25, and the thickness of the i type crystalloid silicon layer 52a of second section photoelectric conversion units 5a is 1.2 μ m.Behind the second silicon composite bed 7 that forms thickness 30nm on second section photoelectric conversion units 5a, form i type crystalloid silicon layer 82, and the 3rd section photoelectric conversion units 8 of the n type microcrystal silicon layer 83 of thickness 15nm of the p type microcrystal silicon layer 81 that contains thickness 15nm, thickness 2.0 μ m.Then, form the Ag layer of the ZnO layer of doped with Al of thickness 90nm and thickness 300nm as backplate 6 by the sputtering method order.The first silicon composite bed 4 and the second silicon composite bed 7 are with the plasma CVD condition film forming identical with the silicon composite bed 4 of embodiment 1.

About three sections stacked photoelectric converters of the present embodiment 12 that as above obtains, measure output characteristic with the condition identical with the situation of table 1, wherein, Voc is 1.905V, Jsc is 10.07mA/cm ², FF is 0.745, Eff is 14.29%.

Comparative example 3

As a comparative example 3, made three sections stacked photoelectric converters shown in Figure 26.The device of this comparative example 3 is only different at the device that omits on the first silicon composite bed 4 and the second silicon composite bed, 7 this point with embodiment 12 shown in Figure 25.Measure the output characteristic of this comparative example 3, wherein, Voc is 1.910V, and Jsc is 9.50mA/cm ², FF is 0.749, Eff is 13.59%.

More as can be known,, also can utilize the reflecting effect of silicon composite bed to increase Jsc the foregoing description 12 and comparative example 3, improve Eff even in three sections stacked photoelectric converters.

About three sections stacked photoelectric converters, further specify comparative example 4, embodiment 13 and embodiment 14 based on prior art.The characteristic of these stacked photoelectric converters gathers with relative value and is shown in table 4.

Table 4

	Silicon composite bed between the first/the second photoelectric conversion units	Silicon composite bed between second/the 3rd photoelectric conversion units	Output characteristic (with comparative example 3 standardization)
							??Voc	??Jsc	??FF	??Eff
			Comparative example 4	Do not have	Do not have	??1.00	??Voc	??Jsc	??FF	??Eff	??1.00	??1.00	??1.00
Embodiment 13	Do not have	Have	Comparative example 4	Do not have	Do not have	??1.00	??1.00	??1.06	??0.99	??1.04	??1.00	??1.00	??1.00
Embodiment 13	Do not have	Have	Embodiment 14	Have	Have	??1.00	??1.00	??1.06	??0.99	??1.04	??1.06	??1.00	??1.05

Comparative example 4

Three sections stacked photoelectric converters of comparative example 4 are not 2.0 μ m and be different with the comparative example 3 of Figure 26 on the 2.5 μ m this point at the thickness of the i type crystalloid silicon layer 82 of the 3rd section photoelectric conversion units 8 only.

Embodiment 13

In embodiment 13, three sections stacked photoelectric converters shown in Figure 27 have been made.The device of this Figure 27 is only at the n type layer of being replaced the second photoelectric conversion units 5a by the n type silicon composite bed 53a of thickness 30nm, and replaced on the p type layer this point of the 3rd photoelectric conversion units 8 different with the device of comparative example 4 by the p type silicon composite bed 81a of thickness 30nm.In addition, n type silicon composite bed 53a piles up with the condition identical with the n type silicon composite bed of embodiment 1, and p type silicon composite bed 81a piles up with the condition identical with the p type silicon composite bed of embodiment 6.

As shown in Table 4, in three sections stacked photoelectric converters of present embodiment 13, utilize the middle reflecting effect of silicon composite bed to compare with comparative example 4, Jsc also increases, and Eff improves.

Embodiment 14

In embodiment 14, three sections stacked photoelectric converters shown in Figure 28 have been made.Compare with comparative example 4, the different feature of present embodiment 14 is, the n type silicon composite bed 33a of n type microcrystal silicon layer 33b, the thickness 50nm of sequential laminating thickness 5nm, and the n type microcrystal silicon layer 33c of thickness 5nm as the n type layer 33 of first section photoelectric conversion units 3a, and the n type silicon composite bed 53a of n type microcrystal silicon 53b, the thickness 50nm of sequential laminating thickness 5nm, and the n type microcrystal silicon layer 53c of thickness 5nm as the n type layer 53 of second section photoelectric conversion units 5a.In addition, n type silicon composite bed 33a and n type silicon composite bed 53a are to pile up with the n type silicon composite bed 4 identical conditions of embodiment 10.

As shown in Table 4, in three sections stacked photoelectric converters of present embodiment 14, utilize the middle reflecting effect of silicon composite bed to compare with comparative example 4, Jsc also increases, and Eff improves.

Embodiment 15

Figure 29 represents the integrated thin film light-to-current inversion module of embodiments of the invention 15.The module of this Figure 29 is only in that reflector 105 in the middle of the ZnO to be changed on silicon composite bed 107 this point into the existing module with Figure 31 different.Thickness of each layer that has in the module of present embodiment 15 and film build method are identical with embodiment 1.The module area of Figure 29 is 910mm * 455mm, and 100 components of photo-electric conversion cutting apart by composition are connected in series mutually.

Comparative example 5～7

As a comparative example 5, as shown in figure 30, made the integrated thin film light-to-current inversion module in reflector in the middle of not containing.As a comparative example 6, as shown in figure 31, made the module in reflector 105 in the middle of the ZnO that contains the thickness 30nm by spatter film forming.As a comparative example 7, shown in figure 32, made the module that contains reflector 105 and the 3rd separating tank 124 in the middle of the ZnO.

In the table 5, about the integrated thin film light-to-current inversion module of embodiment 15 and comparative example 5～7, gathered with table 1 in the output characteristic measured of identical condition.

Table 5

	Structure	The 3rd separating tank	Middle reflector	??Voc(V)	??Isc(A)	??FF	???Pmax(W)	???Eff(％)
	Structure	The 3rd separating tank	Middle reflector	??Voc(V)	??Isc(A)	??FF	???Pmax(W)	???Eff(％)	Embodiment 15	Figure 29	Do not have	The silicon composite bed	??132.3	??0.536	??0.712	???50.5	???13.2
Comparative example 5	Figure 30	Do not have	Do not have	??132.9	??0.420	??0.729	???40.7	???10.6	Embodiment 15	Figure 29	Do not have	The silicon composite bed	??132.3	??0.536	??0.712	???50.5	???13.2
Comparative example 5	Figure 30	Do not have	Do not have	??132.9	??0.420	??0.729	???40.7	???10.6	Comparative example 6	Figure 31	Do not have	??ZnO	??108.3	??0.506	??0.524	???28.7	???7.5
Comparative example 7	Figure 32	Have	??ZnO	??136.5	??0.464	??0.694	???43.9	???11.5	Comparative example 6	Figure 31	Do not have	??ZnO	??108.3	??0.506	??0.524	???28.7	???7.5

As shown in Table 5, compare with the comparative example 5 that does not contain middle reflector, in the comparative example 6 in reflector, Voc and FF significantly reduce in the middle of containing ZnO, and maximum power (Pmax) and conversion efficiency (Eff) significantly reduce.This be because, reflector 105 in the middle of the ZnO, link slot 123, and the current path of backplate layer 106 produce leakage current.On the other hand, in the comparative example 7 that contains the 3rd separating tank 124, suppressed such leakage current, compared with comparative example 5, short circuit current (Isc) increases, the about 3W of Pmax summary.

In the embodiment 15 that contains silicon composite bed 107, compare with comparative example 7, Jsc further increases, and Pmax compares with comparative example 5, improves about 10W.This be because, eliminated the area consumption that adopts the 3rd separating tank 124 to cause, improved Isc.In addition, in present embodiment 15, because the place ahead photoelectric conversion units layer 104a, silicon composite bed 107, and rear photoelectric conversion units layer 104b can form continuously by plasma CVD, do not produce air pollution at the interface of silicon composite bed 107 and rear photoelectric conversion units 104b, so the FF raising.

In addition, compare, do not want the 3rd separating tank 124 among the embodiment 15, can reduce the composition number of times, can subdue production cost and time with comparative example 7.In addition, silicon composite bed 107 is owing to only append CO in the plasma CVD apparatus of photoelectric conversion units formation usefulness ₂Gas line get final product film forming, so need be when the film forming in ZnO intermediate layer other film-forming apparatus such as needed sputter equipment.Can significantly subdue production cost.In addition, compare, in embodiment 15, can each reduce the operation that once is transported into, heats and transport substrate, thus, also can subdue production cost and time to plasma CVD apparatus as vacuum plant with comparative example 7.

Embodiment 16

In embodiment 16, similar to Example 2, made two sections stacked photoelectric converters with laminated structure shown in Figure 17.But, in embodiment 16, the photo-electric conversion device of the photo-electric conversion device of sample 1A and sample 1B is with slightly different technology manufacturing.

In sample 1A, at first on transparent glass substrate 1, form with SnO ₂Transparent electrode layer for principal component.Then, after substrate in will importing first plasma CVD apparatus heats up, form the first of thickness of p type noncrystalline carbonization silicon layer 31, i type uncrystalline silicon light-to-current inversion layer 32 and the n type silicon composite bed 4 of uncrystalline silicon photoelectric conversion units 3 respectively with the thickness of 15nm, 300nm, 40nm.

In the membrance casting condition of the first of this n type silicon composite bed 4, gas flow ratio is SiH ₄/ CO ₂/ PH ₃/ H ₂=1/3/0.025/200, supply frequency is 13.56MHz, and power density is 120mW/cm ², underlayer temperature is 180 ℃.In the first of the n type silicon composite bed 4 that forms, oxygen concentration is 42 atom %, is 2.0 to the refractive index of the light of wavelength 600nm.

After finishing the accumulation of n type silicon composite bed 4 firsts, carry out the vacuum exhaust of film forming room, then, directly substrate be transplanted on the discharge chamber of first plasma CVD apparatus, to this indoor be full of nitrogen rapidly after, substrate is fetched in the atmosphere.

Then, substrate was placed (atmospheric exposure) after 40 minutes in atmosphere, import in second plasma CVD apparatus, heat up, form the second portion of the thickness of n type silicon composite bed 4 with the thickness of 10nm.The first of the refractive index of the second portion of this n type silicon composite bed 4 and oxygen concentration and the silicon composite bed 4 that formed by first plasma CVD apparatus is roughly the same.

Then, in the second identical plasma CVD apparatus, form p type microcrystal silicon layer 51, non-doping i type crystalloid silicon photoelectric conversion units layer 52, the n type microcrystal silicon layer 53 of crystalline silicon photoelectric conversion units 5 respectively with the thickness of 15nm, 2.5 μ m, 15nm.Then, as backplate 6, utilize sputtering method to pile up in proper order to have mixed the ZnO layer of thickness 90nm of A1 and the Ag layer of thickness 300nm.

It is different with the device of sample 1A on crystalline silicon photoelectric conversion units 5 this point that the stacked photoelectric converter of sample 1B only is to form continuously in the same plasma CVD apparatus uncrystalline silicon photoelectric conversion units 3.That is, in the device of sample 1B, the thickness integral body of n type silicon composite bed 4 is piled up in same plasma CVD apparatus continuously, substrate is not fetched in the atmosphere midway.

About above-mentioned sample 1A and the photo-electric conversion device of sample 1B, with with table 1 in identical condition measure light-to-signal transfer characteristic, the relative value of the conversion efficiency of the photo-electric conversion device of its result and sample 1B sample 1A relatively is 1.01, although carry out atmospheric exposure, still show high characteristic.

Embodiment 17

In embodiment 17, similar to Example 1, made the photo-electric conversion device with laminated structure shown in Figure 10.But, in Figure 17, make with slightly different technology with the photo-electric conversion device of sample 2A and the photo-electric conversion device of sample 2B.

The technology of the manufacturing process of the photo-electric conversion device of sample 2A and sample 1A is similar, in first plasma CVD apparatus, form p type noncrystalline carbonization silicon layer 31, i type uncrystalline silicon light-to-current inversion layer 32, n type microcrystal silicon layer 33, and the first of the thickness of n type silicon composite bed 4 of uncrystalline silicon photoelectric conversion units 3 respectively with the thickness of 15nm, 300nm, 10nm and 40nm.That is, sample 2A only before forming n type silicon composite bed 4, forms than different with sample 1A on high n type microcrystal silicon layer 33 this point of this silicon composite bed conductivity and crystallization rate.In such sample 2A, by forming n type microcrystal silicon layer 33 earlier, can reduce the contact resistance at the interface of i type noncrystalline silicon layer 32 and silicon composite bed 4, compare with the situation of sample 1A, can further improve light-to-signal transfer characteristic.

The stacked photoelectric converter of sample 2B is being piled up the integral thickness of n type silicon composite bed 4 in same plasma CVD apparatus continuously, and does not take out on this point substrate different with the device of sample 2A from atmosphere halfway.

About above-mentioned such sample 2A and the photo-electric conversion device of sample 2B, with with table 1 in identical condition measure light-to-signal transfer characteristic, the relative value of the conversion efficiency of the photo-electric conversion device of its result and sample 2B sample 2A relatively is 1.01, although carry out atmospheric exposure, also show high characteristic.

Embodiment 18

In embodiment 18, the oxygen concentration of the silicon composite bed 4 that makes embodiment 17 and the sample that the refractive index of the light of wavelength 600nm has been carried out various changes have further been made.And the light-to-current inversion efficient of carrying out the sample of atmospheric exposure after the first to the thickness that is stacked into silicon composite bed 4 in the table 5 and not carrying out the sample of this atmospheric exposure shows with the relative value with respect to sample 2B.

Table 6

Oxygen concentration in the film (atom %)	Refractive index	Light-to-current inversion efficient (relative value)
		Light-to-current inversion efficient (relative value)				Atmospheric exposure is arranged		No atmospheric exposure
		??0	??4.0	Comparative sample 01A	????0.83	Atmospheric exposure is arranged		No atmospheric exposure		Comparative sample 01B	??0.87
??19	??2.8	??0	??4.0	Comparative sample 01A	????0.83	Comparative sample 02A	????0.92	Comparative sample 02B	??0.95	Comparative sample 01B	??0.87
??19	??2.8	??25	??2.5	Sample 3A	????0.97	Comparative sample 02A	????0.92	Comparative sample 02B	??0.95	Sample 3B	??0.97
??33	??2.2	??25	??2.5	Sample 3A	????0.97	Sample 4A	????0.99	Sample 4B	??0.99	Sample 3B	??0.97
??33	??2.2	??42	??2.0	Sample 2A	????1.01	Sample 4A	????0.99	Sample 4B	??0.99	Sample 2B	??1.00
??51	??1.8	??42	??2.0	Sample 2A	????1.01	Sample 5A	????1.04	Sample 5B	??1.03	Sample 2B	??1.00

According to table 6 as can be known, along with the oxygen concentration rising of silicon composite bed 4, refractive index reduces, and as the effect increase in reflector in the middle of it, light-to-current inversion efficient improves.In addition, when the oxygen concentration of silicon composite bed 4 and refractive index are identical, the sample that relatively has or not atmospheric exposure is more than 25% or refractive index is to obtain the light-to-current inversion efficient identical or higher with sample 2B, the 3B, 4B, the 5B that expose among sample 2A, 3A, 4A, the 5A below 2.5 at oxygen concentration as can be known.Because the silicon composite bed was exactly the film that contains aerobic originally, so be not vulnerable to the harmful effect of high resistanceization that surface oxidation causes etc.Therefore, the oxygen concentration of silicon composite bed is high more, and refractive index is more little, even through the operation of atmospheric exposure, the influence of light-to-signal transfer characteristic is also become few more.

Embodiment 19

Further made with embodiment 17 in the similar various samples of sample 2A.That is, in present embodiment 19, the various changes of the ratio of the first of silicon composite bed 4 integral thickness and second portion have been carried out.And the light-to-current inversion efficient of carrying out the sample of atmospheric exposure after the first to the thickness that is stacked into silicon composite bed 4 in the table 7 shows with the relative value with respect to the comparative sample 02B that does not carry out atmospheric exposure.

Table 7

	Silicon composite bed thickness (nm) 33a/33b	Light-to-current inversion efficient (relative value)
	Silicon composite bed thickness (nm) 33a/33b	Light-to-current inversion efficient (relative value)	Comparative sample 02B	(no atmospheric exposure)	??1.00
Comparative sample 03A	????0/50	??0.97	Comparative sample 02B	(no atmospheric exposure)	??1.00
Comparative sample 03A	????0/50	??0.97	Sample 6A	????10/40	??1.00
Sample 7A	????20/30	??1.00	Sample 6A	????10/40	??1.00
Sample 7A	????20/30	??1.00	Sample 8A	????30/20	??1.02
Sample 2A	????40/10	??1.01	Sample 8A	????30/20	??1.02
Sample 2A	????40/10	??1.01	Comparative sample 04A	????50/0	??0.81

As shown in table 7, in comparative sample 03A, the thickness of the silicon composite bed 4 before the atmospheric exposure is 0, promptly, carry out atmospheric exposure between n type microcrystal silicon layer 33 in Figure 10 and the n type silicon composite bed 4, because the surface that contains the n type microcrystal silicon layer 33 of aerobic originally hardly is exposed to the influence of atmosphere, make and compare that light-to-current inversion efficient reduces a little with comparative sample 2B.In addition, in comparative sample 04A, the thickness of the silicon composite bed 4 after the atmospheric exposure is 0, promptly carry out atmospheric exposure between n type silicon composite bed 4 in Figure 10 and the p type microcrystal silicon layer 51, because being the tunnel junction interface between photoelectric conversion units, the np junction interface is exposed to atmosphere, so compare with comparative sample 02B, light-to-current inversion efficient significantly reduces.

On the other hand, sample 6A, 7A, 8A and 2A all be before will carrying out atmospheric exposure and atmospheric exposure after and then form the part of the thickness of n type silicon composite bed, compare with the comparative sample 02B that does not carry out atmospheric exposure, obtain equal or higher at least light-to-current inversion efficient.Particularly in sample 8A and 2A, it is that 02B compares with comparative sample more than 60% that the ratio of the first that the integral thickness of n type silicon composite bed 4 is formed before atmospheric exposure increases, and can obtain higher light-to-current inversion efficient.Consider as its reason, after atmospheric exposure, substrate imported in second plasma CVD apparatus before the film forming, in again between the heating of the vacuum exhaust of carrying out film forming room and substrate, has the effect of removing the superfluous dopant atom in silicon composite bed 4 and the conductive layer, the ratio of the first of the silicon composite bed that this effect forms before atmospheric exposure is brought up to the 60% more remarkable when above of integral thickness, and its result improves light-to-current inversion efficient.

Embodiment 20

In embodiment 20, similar to Example 1, made the photo-electric conversion device with laminated structure shown in Figure 10.But, in embodiment 20, carry out the photo-electric conversion device that various samples have been made in various changes by gas mixture ratio with the plasma CVD of silicon composite bed 4.

In the sample 9, at first on transparent glass substrate 1, form with SnO ₂ Transparent electrode layer 2 for principal component.Then, after the substrate intensification that will import in the plasma CVD apparatus, form p type noncrystalline carbonization silicon layer 31, i type uncrystalline silicon light-to-current inversion layer 32, n type microcrystal silicon layer 33 and the n type silicon composite bed 4 of uncrystalline silicon photoelectric conversion units 3 respectively with the thickness of 15nm, 300nm, 10nm, 50nm.

The plasma CVD condition of n type silicon composite bed 4 is: gas flow ratio is SiH ₄/ CO ₂/ PH ₃/ H ₂=1/5/0.025/360, supply frequency is 13.56MHz, and power density is 150mW/cm ², underlayer temperature is 180 ℃.In addition, in the n type silicon composite bed that on glass substrate, forms under with identical therewith condition, be 1.83 to the refractive index of the light of wavelength 600nm with thickness 300nm, utilize that phosphorus concentration is 6.0 * 10 in the film that secondary ion mass spectrometry with halogen labeling (SIMS) obtains ²⁰Cm ^-3, oxygen concentration is 52 atom %, is 2.5 based on the TO pattern peak value of crystalline silicon phase with respect to the strength ratio (Ic/Ia) based on the TO pattern peak value of the amorphous alloy phase in the raman scattering spectrum.

Then, in plasma CVD apparatus, form i type crystalloid silicon light-to-current inversion layer 52, and the n type microcrystal silicon layer 53 of the p type microcrystal silicon layer 51 of crystalline silicon photoelectric conversion units 5, non-doping respectively with the thickness of 15nm, 2.5 μ m, 15nm.Then, form the Ag layer of the ZnO layer of thickness 90m of the A1 that mixed and thickness 300nm as backplate 5 by the sputtering method order.

Doped raw material gas PH in the plasma CVD of the n type silicon composite bed 4 that sample 10～12 and comparative sample 05～07 only contain in them ₃SiH with respect to silicon unstrpped gas ₄Mixing ratio in 0.01～0.1 scope, have on the various change this point different with sample 9.

In table 8, about sample 9～12 and comparative sample 05～07, gas mixture ratio when having represented to pile up silicon composite bed 4, refractive index, phosphorus concentration, oxygen concentration to the light of wavelength 600nm, and raman scattering spectrum in peak strength than (Ic/Ia), the light-to-current inversion rate represents for the relative value of benchmark in order to sample 9.

Table 8

	Gas mixture ratio SiH ₄/CO ₂/PH ₃/H ₂	Refractive index	Phosphorus concentration (cm ³)	Oxygen concentration (%)	????Ic/Ia	Conversion efficiency (relative value)
	Gas mixture ratio SiH ₄/CO ₂/PH ₃/H ₂	Refractive index	Phosphorus concentration (cm ³)	Oxygen concentration (%)	????Ic/Ia	Conversion efficiency (relative value)	Comparative sample 05	????1/5/0.01/360	????1.76	?2.4×10 ²⁰	????54	????0.9	????0.81
Sample 10	????1/5/0.012/360	????1.79	?3.1×10 ²⁰	????53	????1.5	????0.95	Comparative sample 05	????1/5/0.01/360	????1.76	?2.4×10 ²⁰	????54	????0.9	????0.81
Sample 10	????1/5/0.012/360	????1.79	?3.1×10 ²⁰	????53	????1.5	????0.95	Sample 9	????1/5/0.025/360	????1.83	?6.0×10 ²⁰	????52	????2.5	????1.00
Sample 11	????1/5/0.05/360	????1.86	?1.1×10 ²¹	????52	????3.0	????0.97	Sample 9	????1/5/0.025/360	????1.83	?6.0×10 ²⁰	????52	????2.5	????1.00
Sample 11	????1/5/0.05/360	????1.86	?1.1×10 ²¹	????52	????3.0	????0.97	Sample 12	????1/5/0.07/360	????1.88	?1.8×10 ²¹	????51	????3.3	????0.95
Comparative sample 06	????1/5/0.08/360	????1.9	?2.0×10 ²¹	????50	????3.6	????0.91	Sample 12	????1/5/0.07/360	????1.88	?1.8×10 ²¹	????51	????3.3	????0.95
Comparative sample 06	????1/5/0.08/360	????1.9	?2.0×10 ²¹	????50	????3.6	????0.91	Comparative sample 07	????1/5/0.1/360	????1.95	?2.5×10 ²¹	????48	????4.0	????0.89

Shown in the comparative sample in the table 8 05, low as the phosphorus concentration of silicon composite bed, then its refractive index is low, but because Ic/Ia is low, thus constitute high resistance, because of the influence of the series resistance that increases stacked photoelectric converter makes the reduction of light-to-current inversion efficient.On the other hand, phosphorus atoms also has the effect that promotes that silicon crystal is grown up mutually, as sample 9～12, under the situation that increases phosphorus concentration, utilizes the effect that multiplies each other of the increase of the increase of Ic/Ia and doping content, and the conductivity of silicon composite bed significantly improves.But, as in the comparative sample 06～07, if PH ₃Mixing ratio and phosphorus concentration too high, although the conductivity height of silicon crystal phase then can cause light-to-signal transfer characteristic and reduces because superfluous phosphorus atoms is sneaked into the influence of crystalloid silicon photoelectric conversion units 5 sides.Therefore, from obtain relative value be the high light-to-current inversion efficient more than 0.95 sample 9～12 the result as can be known, preferred phosphorus concentration is 3 * 10 ²⁰～1.8 * 10 ²¹Cm ^-3Scope in, and preferred PH ₃/ SiH ₄Gas mixture ratio is in 0.012～0.07 scope.

Further in the plasma CVD of the n type silicon composite bed 4 that only in them, contains of sample of making 13～15 and comparative sample 08～09 with respect to silicon unstrpped gas SiH ₄Oxygen unstrpped gas CO ₂Mixing ratio in 2～7 scope, carried out on the various change this point different with sample 9.

In table 9, about sample 9,13～15 and comparative sample 08～09, shown gas mixture ratio when piling up silicon composite bed 4, refractive index, phosphorus concentration, oxygen concentration to the light of wavelength 600nm, and the peak strength of raman scattering spectrum than (Ic/Ia), the light-to-current inversion rate represents for the relative value of benchmark in order to sample 9.

Table 9

	Gas mixture ratio SiH ₄/CO ₂/PH ₃/H ₂	Refractive index	Phosphorus concentration (cm ³)	Oxygen concentration (%)	????Ic/Ia	Conversion efficiency (relative value)
	Gas mixture ratio SiH ₄/CO ₂/PH ₃/H ₂	Refractive index	Phosphorus concentration (cm ³)	Oxygen concentration (%)	????Ic/Ia	Conversion efficiency (relative value)	Comparative sample 08	??1/2/0.025/360	??2.35	?1.2×10 ²¹	??31	????4.3	??0.92
Sample 13	??1/3/0.025/360	??2.0	?9.1×10 ²⁰	??42	????3.8	??0.95	Comparative sample 08	??1/2/0.025/360	??2.35	?1.2×10 ²¹	??31	????4.3	??0.92
Sample 13	??1/3/0.025/360	??2.0	?9.1×10 ²⁰	??42	????3.8	??0.95	Sample 14	??1/4/0.025/360	??1.92	?7.9×10 ²⁰	??49	????3.1	??0.99
Sample 9	??1/5/0.025/360	??1.83	?6.0×10 ²⁰	??52	????2.5	??1.00	Sample 14	??1/4/0.025/360	??1.92	?7.9×10 ²⁰	??49	????3.1	??0.99
Sample 9	??1/5/0.025/360	??1.83	?6.0×10 ²⁰	??52	????2.5	??1.00	Sample 15	??1/6/0.025/360	??1.76	?5.1×10 ²⁰	??56	????1.5	??0.95
Comparative sample 09	??1/7/0.025/360	??1.71	?4.3×10 ²⁰	??59	????0.7	??0.82	Sample 15	??1/6/0.025/360	??1.76	?5.1×10 ²⁰	??56	????1.5	??0.95

Shown in the comparative sample in the table 9 08, few at the concentration of oxygen atoms of silicon composite bed, when refractive index was high, its conductivity raise, but reflecting effect weakens, and absorption loss also increases, and can not obtain the high conversion efficiency of stacked photoelectric converter.In comparative sample 09, though the concentration of oxygen atoms of silicon composite bed raises, refractive index reduces, but because Ic/Ia is low, silicon crystal is mutually considerably less, so the silicon composite bed constitutes high resistance, the influence that the series resistance of stacked photoelectric converter increases reduces light-to-current inversion efficient.Therefore, from the result that obtains sample 9 that relative value is the high light-to-current inversion efficient more than 0.95 and 13～15 as can be known, in the silicon composite bed, refractive index preferably is equal to or less than 2, concentration of oxygen atoms preferably is equal to or greater than 40%, and the peak strength of raman scattering spectrum preferably is equal to or greater than 1.5 than Ic/Ia.

As mentioned above, according to the present invention, can improve the light-to-current inversion efficient of lamination type film photoelectric converting means and lamination type film photoelectric conversion module, and can reduce manufacturing cost.

Claims

1, a kind of stacked photoelectric converter, it is characterized in that, go up from light incident side sequential laminating one conductive layer (31 at substrate (1), 51), the light-to-current inversion layer (32 of essence intrinsic semiconductor, 52) and contain reverse conductive layer (33,53) a plurality of photoelectric conversion units (3,5), the reverse conductive layer (33) and in the described conductive layer (51) in the rear photoelectric conversion units (5) of this place ahead photoelectric conversion units (3) configuration at least one that relatively are disposed in the place ahead photoelectric conversion units (3) of light incident side have silicon composite bed (4) in its part at least, described silicon composite bed (4) has the thickness of 20nm～130nm and the oxygen concentration of 25 atom %～60 atom %, contains Si-rich phase at the amorphous alloy of silicon and oxygen in mutually.

2, stacked photoelectric converter as claimed in claim 1 is characterized in that, described Si-rich phase contains the silicon crystal phase.

3, stacked photoelectric converter as claimed in claim 1 is characterized in that, described Si-rich phase contains the uncrystalline silicon of doping.

4, stacked photoelectric converter as claimed in claim 1 is characterized in that, described silicon composite bed is 1.7～2.5 to the refractive index of the light of wavelength 600nm.

5, stacked photoelectric converter as claimed in claim 1, it is characterized in that, described substrate is transparent, the reflection of light spectrum that incides the photoelectric conversion units of described lamination by this substrate has the maximum and the minimum of at least one reflectivity respectively in the scope of wavelength 500nm～800nm, described maximum and described minimizing difference are equal to or greater than 1%.

6, stacked photoelectric converter as claimed in claim 1 is characterized in that, the dark conductivity of described silicon composite bed is 10 ^-8S/cm～10 ^-1S/cm.

7, stacked photoelectric converter as claimed in claim 1, it is characterized in that, in described silicon composite bed, what measured by Raman scattering is 0.5～10 based on the TO pattern peak value of crystalline silicon phase with respect to the strength ratio based on the TO pattern peak value of described amorphous alloy phase.

8, stacked photoelectric converter as claimed in claim 1 is characterized in that, the optical gap of described silicon composite bed is equal to or greater than 2.2eV.

9, stacked photoelectric converter as claimed in claim 1, it is characterized in that, in described silicon composite bed, the interband that is subjected to the Ols of X linear light electron spectroscopy for chemical analysis mensuration encourages the photoelectronic the top energy of loss and the energy difference of the photoelectronic peak energy of Ols to be equal to or greater than 2.2eV.

10, stacked photoelectric converter as claimed in claim 1 is characterized in that, the dopant atom concentration in the described silicon composite bed is 3 * 10 ²⁰～1.8 * 10 ²¹Cm ^-3Scope in.

11, a kind of manufacture method that is used to make stacked photoelectric converter as claimed in claim 1, it is characterized in that, after in the plasma CVD reative cell, being stacked into the part of full depth of described silicon composite bed, temporarily described substrate is fetched in the atmosphere, the surface of described silicon composite bed is exposed in the atmosphere, then, described substrate is imported in the plasma CVD reative cell, pile up the remainder of the full depth of described silicon composite bed.

12, manufacture method as claimed in claim 11 is characterized in that, be stacked into the full depth of described silicon composite bed more than 60% after, described substrate is fetched into the atmosphere from described plasma CVD reative cell.

13, a kind of being used for as making the manufacture method of the described stacked photoelectric converter of claim 1, it is characterized in that doped raw material gas is in 0.012～0.07 scope with respect to the mixing ratio of silicon unstrpped gas when piling up described silicon composite bed in the plasma CVD reative cell.

14, a kind of integrated-type light-to-current inversion module, it is characterized in that, go up first electrode layer (103) of sequential laminating at substrate (102), a plurality of photoelectric conversion units layer (104a, 104b), and the second electrode lay (106) is by a plurality of separating tanks (121,122) separate, to form a plurality of components of photo-electric conversion (110), and these elements are situated between and are electrically connected in series mutually by a plurality of link slots (123), on each described components of photo-electric conversion from light incident side sequential laminating one conductive layer, the light-to-current inversion layer of essence intrinsic semiconductor, and contain a plurality of photoelectric conversion units of reverse conductive layer, the described reverse conductive layer and in the described conductive layer in the described photoelectric conversion units (104b) at the rear of this place ahead photoelectric conversion units configuration at least one that relatively are disposed in the described photoelectric conversion units (104a) in the place ahead of light incident side have silicon composite bed (107) in its part at least, described silicon composite bed (107) has the thickness of 20nm～130nm and the oxygen concentration of 25 atom %～60 atom %, contains Si-rich phase at the amorphous alloy of silicon and oxygen in mutually.

15, integrated-type light-to-current inversion module as claimed in claim 14, it is characterized in that, described first electrode layer (103) is separated into a plurality of zones of corresponding described a plurality of components of photo-electric conversion (110) by a plurality of first separating tanks (121), described a plurality of photoelectric conversion units layer (104a, 104b) and described the second electrode lay (106) be separated into a plurality of zones of corresponding described a plurality of elements by a plurality of second separating tanks (122), be used to be electrically connected described first electrode of adjacent mutually described element and the link slot (123) of described second electrode is arranged between described first separating tank (121) and described second separating tank (122).