CN101467022A - Method of phot0-reflectance characterization of strain and active dopant in semiconductor structures - Google Patents

Abstract

A new method of photo-reflectance characterization of strain and active dopant in semiconductor structures has been developed for characterization of physical properties of semiconductor structures. The underlying principle of the strain and active dopant characterization technique is to measure photo-reflectance signals occurring nearby to interband transitions in the semiconductor bandstructure and which are highly sensitive to strain and/or active dopant through the effect of the nanometer scale space charge fields induced at the semiconductor surface. To attain this, the present disclosure comprises an intensity modulated pump laser beam and a continuous wave probe laser beam, focused coincident on a semiconductor structure. The pump laser provides approximately 15 mW optical power in the NIR-VIS. The pump light is amplitude modulated by a signal generator operating in the range of 100kHz-50MHz. The probe beam is approximately 5 mW operating in the VIS-UV and is generally of wavelength nearby to strong optical absorptions in the semiconductor structure. The pump and probe are focused co-incident to a micrometer scale spot on the sample. Probe specular reflections are collected and the pump wavelength light is removed using a color filter. The remaining probe light is directed onto a photodiode and converted to an electrical signal. The probe AC signal then contains pump induced changes in the semiconductor material optical response. Phase sensitive measurement is performed on the photodiode output and the AC signal is divided by the DC reflectance signal. Thus photo-reflectance information is recorded as a function of probe wavelength, modulation frequency, pump intensity, and pump and probe polarizations.

Description

The light of the adulterant of strain and activation-reflection characteristic depicting method in the semiconductor structure

The cross reference of relevant application

The present invention requires the rights and interests of U.S. Provisional Patent Application of submitting on October 27th, 2,005 60/730,293 and the U.S. Provisional Patent Application of submitting on July 17th, 2,006 60/831,363, here all sidedly in conjunction with these two patented claims as a reference.

Invention field

The present invention relates to the optical characteristics portrayal of semiconductor structure, especially, relate to making and use up-modulate the characteristic that reflectivity provides the adulterant of strain and activation in the semiconductor structure.

Background technology

In making the technology controlling and process of electron device, need highly sensitive non--destructive measurement techniques.In order to obtain early stage possible feedback at production period, need before the device completion, provide its characteristic electron.Importantly, the physical phenomenon of domination device work occurs in as thin as a wafer the active layer, is difficult to provide its characteristic owing to their volume is very little.For example, advanced transistor arrangement can comprise the thin silicon layer that strain is arranged, and wherein transistorized electrical specification has been controlled in the strain of silicon crystal lattice.Can not provide the characteristic electron of these films effectively such as the weights and measures technology of the quasi-tradition of ellipsometry.Fortunately, can use the optical technology that is known as light-reflection to provide the characteristic electron of film.Bring out the minor cycle variation in the electronics-hole sum of laser pumping wave beam in interested film of traditional light-reflection configuration use amplitude modulation(PAM).Use phaselock technique to use second light beam that meets with the pumping wave beam of modulating to monitor the reflectance varies of little sampling then.This discloses the new light-reflectivity weights and measures technology of description application and provides the activation characteristic electron of nano thickness silicon fiml.

By using near the detection wavelength of transition energy between first strong band among the Si, here the light of the adulterant of strain and activation in the semiconductor structure of Jie Shiing-reflection characteristic depicting method obtains the sensitivity of Si nanometer film structure characteristic electron, and this occurs in the wavelength place of about 375nm.Near this transition, light-reflection (PR) signal generally shows the shape of sharp-pointed derivative shape.Usually, the PR signal is taked Δ R/R=α Δ ε ₁+ β Δ ε ₂Form, wherein α and β are " the Seraphin coefficients " that comprises membrane stack (filmstack) information, and Δ ε ₁With Δ ε ₂It is respectively the variation of bringing out in the real part and the pumping in the imaginary part of dielectric function (Seraphin, 1965).In other words, Δ ε ₁With Δ ε ₂The modulation that the pumping of description film characteristics is brought out.Can be write three subderivatives long-pending as follows of the energy of free carrier and semiconductor dielectric function as these variations of bringing out: ${\mathrm{\Δ\ϵ}}_j={\∂}^3\left({\mathrm{\ω\ϵ}}_i\right)/{\∂\mathrm{\ω}}^3\×U_p,$ U wherein _pBe the free carrier energy, and ω is photon frequency (Aspnes, 1980).Therefore, select the motivation of wavelength of the detection wave beam of 375nm to be Δ ε for Si ₁With Δ ε ₂Sharp-pointed derivative form.Can directly calculate three subderivative items from the known semiconductor optical constant.Therefore total PR signal becomes $\mathrm{\ΔR}/R=\mathrm{Re}[(\mathrm{\α}-\mathrm{i\β})\×{\∂}^3\left(\mathrm{\ω\ϵ}\right)/{\∂\mathrm{\ω}}^3]]\×U_p.$ In the semiconductor tape structure, three subderivative functional forms only learn near high light absorption place be only big, therefore can be with big precision these features of emanating.Why Here it is allows the PR technology accurately to measure the strain of the silicon layer of nanoscale strain, for example, because the strong optical absorption near 375nm suffers accurate skew among the Si under strain.Approach these strong optical absorption, the amplitude of PR response also has good sensitivity to the electric field in the silicon transistor channel region of activation: notice that the free electron energy is by expression formula U _p=e ²h ²F ²/ 24m ω ²Provide, wherein e is an electric charge, and h is a Planck's constant, and F is that space charge field and m are electron effective masses.The free electron energy also is directly proportional with the carrier density of bringing out, and this can see from Poisson relation: N _e=ε ₀F ²/ 2eV, wherein N _eBe the carrier density of bringing out, V is built-in surface voltage, and ε ₀It is the specific inductive capacity (Shen, 1990) of material.

The subject matter of general commercial light-reflectometer is that the wavelength of not selecting to survey wave beam makes it and learn absorption at the high light of the electronic material of studying to meet (Salnick, 2003; Borden, 2000).Therefore, in traditional light-reflectometer, be that hour wavelength place obtains the PR signal in three subderivatives of dielectric function, therefore unavailable information about band structure.Therefore, traditional light-reflectometer can not usefully be determined internal electric field or strain.On the contrary, these light-reflectometers are responsive (Salnick, 2003) for the damage distribution of the adulterant through injecting.The membrane stack information in the PR signal of being included in is second important, and at the curve that produces the cosine shape as the PR response of the function that injects the degree of depth.In addition, in these light-reflectometers, can not from the implantation dosage dependence, weaken and inject degree of depth dependence.In any situation, can obtain the membrane stack information (Jellison, 1995) that conventional commercial light-reflectometer provides by the normal linearity optical technology such as spectroscopic ellipsometry.

Use is when using so wave beam based on another problem of traditional light-reflectometer of the lamp of the spectroscopic detection wave beam of wavelength high light is learned transition near, they are necessary: i) use monochromator to carry out requiring at each the phase-locked measurement of order at wavelength place, or ii) use a plurality of phase-lock detecting circuits in parallel with the linear photodiode detection arrays.In the situation of using monochromator, total spot measurement time, generally on 5-10 minutes the order of magnitude, this can not satisfy the use of manufacturing in enormous quantities.In the situation of using phase lock circuitry in parallel, the cost of device and complicacy are maximum.In addition, in the traditional light-reflectometer that uses this spectroscopic detection wave beam based on lamp, lamp provides incoherent light, therefore the such point of focal imaging laser beam effectively.In the light-reflection characteristic depicting method of strain in the semiconductor structure of Miao Shuing here and activation adulterant, all these problems all are resolved in first mode.At first, do not need to use monochromator, be preset at interested known wavelength place because laser instrument is surveyed wavelength, or on diversified so known wavelength, scan fast.The second, do not need phase lock circuitry in parallel, because only need a sense photodiode.At last, the use of laser light source allows to require carrying out tight focusing and rapid data is caught according to the technology controlling and process of making in enormous quantities.

The other problem of general commercial light-reflectometer is a wavelength of not selecting the pumping wave beam so that the absorption degree of depth to be provided, and this absorption degree of depth is to be suitable for effectively suction to be generally used for the dielectric substrate of semiconductor in making.For example, in order to aspirate the silicon substrate on the insulant effectively, the requirement that absorbs the degree of depth the pump laser wavelength be limited in less than or be equivalent to the top silicon thickness.This has hinted the suitable pumping wavelength less than about 500nm, the unappeasable condition of general commercial light-reflectometer (Salnick, 2003).

Therefore, when traditional light-reflectometer/spectrometer went for specific purpose that they set about, they were applicable to the activation characteristic electron of nanometer semiconductor structure like that not as this announcement before device is finished.

In these areas, light-reflection characteristic the depicting method of strain in the semiconductor structure of Jie Shiing here and activation adulterant has left the traditional concept and the design of prior art in fact, and provides the quick feature of activation characteristic electron of the nanometer semiconductor structure that is initially in the manufacturing in enormous quantities and a kind of device of developing when so carrying out.

Summary of the invention

Owing to be present in above-mentioned shortcoming intrinsic in the known type spectroscopy of the prior art at present, this announcement provides the new method of the light-reflectance signature of strain in the semiconductor structure and activation adulterant.

The general objects of this announcement that will describe in more detail provides strain in the semiconductor structure and a kind of method of light-reflectance signature of activation adulterant subsequently, this method has the many advantages in the above-mentioned spectroscopy, and many novel features, a kind of method that this has produced the light-reflectance signature of strain in the semiconductor structure and activation adulterant does not have individually in any prior art or met, obviously carried out, advised or hinted this method in advance by the form of any combination.

The following principle of emergent property portrayal technology is the little wavelength shift of measuring near the light-reflected signal that takes place the transition between strong band in the semiconductor tape structure.The position at PR peak allows directly definite thin film physics characteristic such as strain.The following principle of activation dopant properties portrayal technology is to measure near the light-reflected signal that takes place the transition between strong band in the semiconductor tape structure equally, and by the effect of the nanoscale space charge field that brings out at the semiconductor surface place, this is tetchy for activated adulterant.The PR signal allows directly to determine the thin film physics characteristic, such as the activation doping content.Therefore, the light-reflection characteristic depicting method of strain in the semiconductor structure and activation adulterant provides the ability of the light-reflective information of generation and the activation characteristic electron that writes down relevant nanometer semiconductor structure.

In order to reach this purpose, as a possible embodiment, this announcement is included in the diode laser pumped wave beam of the about 15mW that works among NIR-VIS.By the signal generator that is operated in the 100kHz-50MHz scope pumping wave beam is carried out amplitude modulation(PAM).Directly the modulated pumping laser instrument maybe can come the modulated pumping laser instrument by traditional electricity-light or sound-light modulation techniques.Can change the pump beam polarization by fixed polarizer.As a possible embodiment, survey the diode laser wave beam that wave beam comprises the about 5mW that is operated in VIS-UV.By using the dichromatism optical splitter can make pump beam and detecting light beam conllinear.The pump beam of conllinear and detecting light beam are directed on the micron order point in the sampling, and the reflection of collecting mirror.Use color filter to make the pump light decay then, then remaining detection light of the reflectivity that comprises modulated sampling is focused on the photodiode, and convert electric current to.Make this electric current by the amplitude of measurement of reflectivity variation and locking (lock-in) amplifier of phase place.Store this PR signal then as the function of surveying wavelength, pump intensity and pump beam and detecting light beam polarization.Therefore caught light-reflective information about the activation electronic property of nanometer semiconductor structure.

Semiconductor material as the theme of this announcement can be the semiconductor material of any kind, and can include but are not limited to II-VI family semiconductor material or III-V family semiconductor material.In certain embodiments, this material can comprise silicon, carbon, germanium, silit, SiGe, boron, phosphorus, arsenic or their any combination, or they can comprise gallium arsenide, aluminium arsenide, gallium nitride, aluminium nitride, indium nitride, gallium phosphide, indium phosphide, indium arsenide or their any combination.

Therefore summarized some prior features of this announcement more widely, described in detail, and so that understood the contribution that originally is disclosed in technical elements preferably so that can understand it preferably.Some additional features of this announcement will be described hereinafter.

Aspect this, before explaining at least one embodiment of this announcement in detail, be appreciated that the application of this announcement is not limited to following explanation or shown CONSTRUCTED SPECIFICATION of accompanying drawing and parts arrangement.This announcement can be used in other embodiment, and can realize in every way and carry out.Equally, be appreciated that employed word and term are for illustrative purposes here, should not be regarded as restriction.Can realize this announcement by the shown form of accompanying drawing, yet, be noted that in fact accompanying drawing just schematically, can modify in shown ad hoc structure.

Description of drawings

Following accompanying drawing forms the part of this instructions, and these accompanying drawings that comprised are further showed some aspect of this announcement.By understanding this announcement preferably with reference to the one or more in these accompanying drawings and in conjunction with the detailed description of shown specific embodiment here.

Fig. 1 illustrates the exemplary membrane structure that strain is arranged that the emergent property portrayal technology that can use this announcement is analyzed;

Fig. 2 comprises the configuration according to the light-reflection unit of this announcement, can use this device provide in the semiconductor structure strain and the activation adulterant light-reflection characteristic;

Fig. 3 comprises the illustrative arrangement of the light-reflection unit detection wave beam polarization according to this announcement, can be used to provide strain and the light-reflection characteristic that activates adulterant in the semiconductor structure;

Fig. 4 comprises the " E in the silicon that is caused by biaxial strain ₁" the schematic skew of interband transition and the measuring principle that the emergent property portrayal technology of this announcement is shown;

Fig. 5 is as the DC reflectivity function of top silicon thickness and SiGe layer Ge concentration, that calculate for the thin silicon films on thick germanium-silicon layer top on to optics at λ=375nm place;

Fig. 6 is as the Seraphin coefficient function of top silicon thickness and SiGe layer Ge concentration, that calculate for the thin silicon films on the thick germanium-silicon layer on to optics at λ=375nm place

Fig. 7 is as the Seraphin coefficient function of top silicon thickness and SiGe layer Ge concentration, that calculate for the thin silicon films on the thick germanium-silicon layer on to optics at λ=375nm place

Fig. 8 be when the modulating frequency of 20MHz to set of samples 1 in experiment PR signal of marking and drawing of each sampling;

Fig. 9 be when the modulating frequency of 20MHz to set of samples 2 in experiment PR signal of marking and drawing of each sampling;

Figure 10 illustrates the exemplary silicon nanometer film structure through injection/annealing that light-the reflection characteristic depicting method is analyzed of the activation adulterant in the semiconductor structure that can use this announcement;

Figure 11 is that the space charge field of the F=430kV/cm that brings out for pumping is near SiE ₁The PR signal of the calculating at interband transition energy place;

Figure 12 is as the Seraphin coefficient function of the implantation dosage and the degree of depth, that calculate for the thin implant damage layer on the thick silicon substrate on to optics at λ=633nm place

Figure 13 is as the Seraphin coefficient function of the implantation dosage and the degree of depth, that calculate for the thin injection damaged layer on the thick silicon substrate on to optics at λ=375nm place

Figure 14 is as the Seraphin coefficient function of the implantation dosage and the degree of depth, that calculate for the thin injection damaged layer on the thick silicon substrate on to optics at λ=375nm place

Figure 15 is the experiment PR signal that has the As wafer through injecting and annealing of 10nm target knot (targeted junction) degree of depth when the modulating frequency of 2MHz;

Figure 16 is the experiment PR signal that has the As wafer through injecting and annealing of 20nm target junction depth when the modulating frequency of 2MHz;

Figure 17 is the experiment PR signal that has the As wafer through injecting and annealing of 30nm target junction depth when the modulating frequency of 2MHz;

Figure 18 is the experiment PR signal that has the As wafer through injecting and annealing of 40nm target junction depth when the modulating frequency of 2MHz;

Figure 19 be mark and draw as the function of junction depth, shown in Figure 15-18 through injecting and the experiment PR signal of the As wafer of annealing;

Figure 20 be " low dosage " that mark and draw as the function of junction depth, shown in Figure 15-18 through injecting and the experiment PR signal of the As wafer of annealing;

Figure 21 is the experiment PR signal of the As wafer of " only inject " (not have to anneal) of having 10nm target junction depth when the modulating frequency of 2MHz;

Figure 22 is the experiment PR signal of As wafer that has " only inject " of 20nm target junction depth when the modulating frequency of 2MHz;

Figure 23 is the experiment PR signal of As wafer that has " only inject " of 30nm target junction depth when the modulating frequency of 2MHz;

Figure 24 is the experiment PR signal of As wafer that has " only inject " of 40nm target junction depth when the modulating frequency of 2MHz;

Figure 25 is the experiment PR signal of the As wafer of " only injecting " that mark and draw as the function of junction depth, shown in Figure 21-24.

Embodiment

The feature that regards to strain in the silicon nanostructure and activation adulterant is down discussed the use of the light-reflection characteristic depicting method of strain and activation adulterant in the semiconductor structure.Be appreciated that in the semiconductor structure that can use this announcement strain and the activation adulterant light-reflection characteristic depicting method analyze any semiconductor structure, think that the discussion of silicon nanometer film structure only is exemplary, be not restriction to scope.

Forward accompanying drawing now to and be described, Fig. 1 comprises the light-reflection technology that can use this announcement and provides feature, the exemplary silicon fiml structure through strain in overweening view.Can use molecular beam epitaxy and/or chemical vapour deposition technique and/or metal-organic learn the vapour deposition process growth, comprise silicon substrate 1 through the silicon fiml structure of strain, on silicon substrate, the grown graduate synthetic germanium-silicon layer 2 of increase Ge content (reaching about 10-30% Ge), then be evenly synthetic SiGe layer 3, and be last thin silicon films 4 at last through strain.SiGe layer 2 and 3 forms the virtual SiGe substrate that meets with last silicon crystal lattice, thereby brings out tensile strain in upper silicon layer.In an one exemplary embodiment, be about 10.0nm through the thickness of the last Si layer 4 of strain.

Configuration according to this announcement shown in Figure 2, can use the light-reflection characteristic depicting method of the adulterant of strain and activation in the semiconductor structure to measure from silicon nanometer film structure or any other semiconductor structure spectrum of reflected light through strain, so that provide the physical property of semiconductor structure, such as the energy of interband transition, the carrier concentration and the surface field of activation.As shown in Figure 2, described light-reflection configuration comprises that pump laser 5, detecting laser 6, dichromatism optical splitter 7, polarizing beam splitter 8, achromatic 1/4th-ripple plate 9, reflection sampling 10, color filter 11, photodiode 12, lock-in amplifier 13 and computing machine 14 are with control survey parameter and record reflectance varies.In an one exemplary embodiment, use the direct modulated pumping laser instrument of square wave reference signal intensity from 1 volt of peak-to-peak value of lock-in amplifier 13.By using dichromatism optical splitter 7 to make pump beam and surveying wave beam on same straight line.Use achromatic condenser lens that the wave beam on the same straight line is focused in the reflection sampling 10 then, and use collecting lens to collect.Then use color filter 11 to make the pump light decay.Remaining the detection light that comprises modulated sampling reflectivity is focused on the photodiode 12, and convert electric current to.This electric current is by the amplitude of measurement of reflectivity variation and the lock-in amplifier 13 of phase place.This information is sent to computing machine 14, and computer recording changes as the reflectivity difference of the function of driving frequency.

Pump laser 5 is that photon energy is in tested semi-conductive band gap place or above continuous wave laser.For silicon, band gap occurs in about 1100nm wavelength place.In an one exemplary embodiment, pumping wavelength is about 488nm, and pump laser power is about 15mW.When active layer be the silicon substrate on the insulant thin upper silicon layer so that must be in last Si layer absorptive pumping light when modulating carrier density effectively, this wavelength is particularly useful.Computing machine 14 can be controlled pump laser intensity.Pump laser 5 embodiment are included in the diode laser with about 5mW or above power work of emission in the NIR-VIS wavelength coverage.Can directly modulate or by making electricity consumption-light or sound-light amplitude modulation device carry out external modulation the pump laser wave beam.In an one exemplary embodiment, by from the internal reference signal of lock-in amplifier 13 with the direct modulated pumping laser instrument 5 of high-frequency.Driving frequency changes to 50MHz from about 100kHz.Can also be subjected to computer-controlled polarizer by the angle position and transmit the pumping laser beam.This provides polarized pump wave beam amplitude modulation(PAM), variable.Detecting laser 6 comprises that photon energy is in or the continuous wave laser diode of approaching tested semi-conductive interband transition energy.For silicon, absorption occurs in about 375nm wavelength place between first strong band.In an one exemplary embodiment, probing wave is about and is 375nm, and exploring laser light power is about 5mW.In certain embodiments, detecting laser 6 is that centre wavelength is about 375nm and tunable range is about 10 nanometers or bigger external cavity formula tunable diode laser.Detecting laser 6 embodiment are included in the diode laser with about 10mW or littler power work of emission in the VIS-UV wavelength coverage.By using dichromatism optical splitter 7 to make pump beam and surveying wave beam on same straight line.Use high digital aperture focalizer that the wave beam on the same straight line is focused in the sampling then, and collect the reflection of mirror and be directed to color filter 11.Focus on embodiment and comprise the wave beam device takes place simultaneously, wherein make each laser beam all be focused into 50 microns or littler diameter.Polarization when optical system is passed through in the schematically illustrated exploring laser light bundle of Fig. 3 and it.All optical elements all with separately source wavelength coupling.In case reflected the detection wave beam from reflection sampling 10, it just has the amplitude modulation(PAM) from the pumping modulating frequency place that brings out modulation of sampling optical property.Therefore, surveying wave beam, to comprise form be I ₀The signal of [R (DC)+Δ R (Ω)].Make optical attenuation with color filter 11, and remaining is surveyed light be sent to photodiode 12 from the pumping wave beam.Therefore, photodiode output comprises the electric current that is directly proportional with detectable signal.

DC signal and I from photodiode ₀R is directly proportional, and AC signal and I ₀Δ R is directly proportional.In order to measure Δ R/R, must be to intensity I ₀Carry out normalization.This is by realizing the AC signal divided by the DC signal.The typical amplitude of the Δ R/R of one exemplary embodiment is 10 ^-2-10 ^-6The order of magnitude.Excute phase sensitivity measure in photodiode output, and computing machine 14 record measuring light electric currents.Computing machine 14 can be controlled the polarization of surveying wavelength, modulating frequency, pumping laser intensity and each wave beam.Therefore write down Δ R/R as the function of surveying wavelength, modulating frequency, laser intensity and polarization.These embodiment comprise the modification of the device that does not change basic PR signal.

As described, the following principle of emergent property portrayal technology is to measure in the semiconductor tape structure to occur near the little skew near the light-reflected signal the transition between strong band.Fig. 4 illustrates and is used for using single detection wavelength to monitor the following principle of the strain of thin silicon fiml through strain.Known silicon " the E that takes place at λ ≌ 375nm place ₁" interband transition is to divide under strain and be offset.By: E _±=E ₁+ Δ E _H± Δ E _SProvide through the position of the interband transition energy of strain, wherein Δ E _H(＜0) and Δ E _SCorrespond respectively to the skew that hydrostatics and shear are brought out.These two all is linear in strain, causes the linear direct ratio of total skew and strain.Silicon crystal lattice strain for about 1%, Fig. 4 comprise with without the silicon E of strain ₁Interband transition energy and through the E of red shift _-Interband transition energy corresponding simulating PR signal.As shown, near E ₁The monochrome of interband transition energy is surveyed wave beam, and when having strain, the PR signal will carry out sign modification.Therefore, by be studied without the semi-conductive strong band of strain between transition place or extremely near strong band between transition place select single detection wavelength, the existence of strain is determined in the variation of symbol that just can be by PR response.In addition, such as among Fig. 4 displaying, or extremely near this interband transition place, the PR signal is the linear function of strain.Therefore, can be according to the approximately linear formula: Δ R/R=m χ+b uses the PR signal to monitor the amplitude of strain simply, and wherein χ is a physical strain, and m is the linearly dependent coefficient that experience is determined, and b is little skew.

In PR signal delta R/R and strain relevant, importantly to know the effect of membrane stack on the PR signal.This is by the fundamental relation formula: Δ R/R=α Δ ε ₁+ β Δ ε ₂Provide, wherein α and β are the Seraphin coefficients that comprises membrane stack information, and Δ ε ₁With Δ ε ₂It is respectively the change that pumping is brought out in sampling real part of puppet-dielectric function and the imaginary part.Absorb the degree of depth that the degree of depth is provided with the PR response, therefore be provided with scope, this scope is important for the effect of knowing the membrane stack on the PR signal.At 375nm wavelength place, the absorption degree of depth in the silicon is δ ≌ 22.6nm.This means that for top silicon thickness 375nm surveys wave beam and lost sensitivity apace for following membrane structure greater than 22.6nm.For 10%, 20% and 30% typical SiGe Ge concentration, Fig. 5 comprises the reflectivity as the calculating of the function of top silicon thickness, shown in Figure 1 exemplary membrane structure.By with respect to ε ₁And ε ₂This reflectivity is carried out numercal differential, might calculate the Seraphin coefficient, that is:

With For 10%, 20% and 30% typical SiGe Ge concentration, Fig. 6 and 7 comprises the Seraphin coefficient as the function of top silicon thickness, shown in Figure 1 exemplary membrane structure.It can not be that variation owing to top silicon thickness or Ge concentration causes that the Seraphin coefficient shows any sign change in the observed PR signal in 375nm place in the fact that does not have reindexing on the parameters of interest space.Therefore, any sign modification of Δ R/R must be because the Δ ε that the expression strain exists ₁Or Δ ε ₂Sign change cause.The Seraphin coefficient that calculates also shows the dependence of the Δ R/R of membrane stack parameter.

To exist the PR signal that is associated to change in order showing, to have analyzed two set of samples of the variation of the demonstrative structure that comprises Fig. 1 with strain.If any, interested basic problem is, in each of these groups, which top silicon fiml is subjected to strain.1: one the silicon substrate of set of samples that comprises 5 wafers without strain; Two wafers that on silicon substrate, have lax SiGe (～18.5% Ge); And on silicon substrate, have two wafers silicon fiml, that have lax SiGe (～18.5% Ge) of the additional top of about 6nm thickness through strain.Set of samples 1 is described in the table 1 below.

	#1	#2	#3	#4	#5
						Membrane stack	The Si substrate	Top Si/ SiGe/ substrate	The SiGe/ substrate	Top Si/ SiGe/ substrate	The SiGe/ substrate
％Ge	N/A	～18.5％	～18.5％	～18.5％	～18.5％
						Top Si thickness	N/A	～6nm	N/A	～6nm	N/A

Table 1

Set of samples 2 comprises 6 wafers one, and each comprises that the whole of Fig. 1 pile up, and is changing aspect top silicon thickness and the Ge concentration.Set of samples 2 is described in the following Table 2.

Table 2

Fig. 8 is illustrated in the PR data that the fixed modulation frequency place of 20MHz obtains from set of samples 1.Wafer #1, #3 and #5 without the silicon substrate of strain and lax SiGe wafer, illustrate approximately+1 * 10 ^-5The PR signal.Because PR spectrum is that we can conclude from the linear superposition of top silicon fiml with the response of the SiGe layer that relaxes, if wafer #2 and #4 comprise the top silicon without strain, then the response of these wafers must be positive, and is similar with #5 to wafer #1, #3.Yet, having only wafer of top silicon, wafer #2 and #4 illustrate the PR signal of opposite in sign.In addition, shown in Fig. 6 and 7, the sign change of the PR response of seeing from wafer #2 and #4 can not be the membrane stack effect.Therefore, the strain measurement principle of describing according to Fig. 4, the negative PR signal of seeing from wafer #2 and #4 is because the strain the silicon of top causes.

Fig. 9 is illustrated in the PR data that the fixed modulation frequency place of 20MHz obtains from set of samples 2.Wafer #1, #5 and #6 illustrate～and 1-2 * 10 ^-5The PR signal.Yet, wafer #2, #3 and #4 opposite in sign is shown with amplitude for～3-4 * 10 ^-5The PR signal.By the inspection of his-and-hers watches 2, can see the wafer of negative PR signal, and positive signal is corresponding to the film of the about 20nm of thickness corresponding to top silicon fiml with about 10nm thickness.Yet shown in Fig. 6 and 7, negative PR response can not be the membrane stack effect.This is illustrated in the set of samples 2, makes strain relaxation when the top silicon thickness surpasses about 20nm.The thickness of prediction top silicon fiml during greater than the thickness of about 15nm the independently calculating of strain relaxation supported this conclusion (under the situation here).Under the situation that the result with set of samples 1 simulates, we conclude that wafer #2, #3 and the #4 of set of samples 2 is subjected to strain, and other wafer does not have.

Forward the explanation of activation dopant properties portrayal technology now to, in an exemplary views, Figure 10 comprise can with light-reflection characteristic depicting method of the adulterant of strain and activation in the semiconductor structure of this announcement analyze through inject and through the silicon fiml structure of annealing.Be included in the standard silicon substrate 15 that integrated circuit manufacturing is used through silicon fiml structure that inject and, in this substrate, inject the conforming layer of arsenic (As) adulterant, and after this carry out activation annealing through annealing.In an one exemplary embodiment, input horizon 16 is about 10-40nm at the wafer surface place or near the thickness at wafer surface place.In fact, the adulterant through injecting forms the distribution of classification, so Figure 10 only provides the approximate construction that provides through the optical property of silicon nanometer film structure that inject and through annealing.Produce one group of silicon wafer that injects arsenic, these wafers have the implantation dosage of variation and inject energy.The process modeling that use has 24 wafers of the implantation dosage and the degree of depth is approx at current and manufacturing specification in the future.Change and inject energy, and change dosage with generation scope about 10 with the degree of depth of the about 10nm of generation scope to 40nm ¹⁸Atom/cubic centimetre is to 10 ²⁰The specified dosage density of atom/cubic centimetre.Inject division for each, produce through annealing and without the wafer of annealing.Table 3 comprises the information of model, comprises the dopant profiles of estimation.Exist 4 to inject energy: wafer #1-6,7-12,13-18 and 19-24 and correspond respectively to 10,20,30 and the injection degree of depth of 40nm.Each of these target depths comprises that further the order of magnitude is 10 ¹², 10 ¹³With 10 ¹⁴Three dosage divisions of ion/square centimeter.Maximum dose level is corresponding to about 1 * 10 ¹⁸The density of ion/cubic centimetre.At last, carry out the annealing division, comprise 1000 ℃ of single annealing of locating 5 seconds.This annealing is intended to produce the maximum dose activation under all dosage and the density conditions.Do not carry out making dosage spread minimized trial.

Wafer number	Inject energy	Target depth (nm)	Spread (nm)	Dosage (1/cm2)	Density (1/cc)	Annealing conditions
							1	7keV	10.2	3.6	1.00E+12	9.80E+17	XX
2	7keV	10.2	3.6	1.00E+12	9.80E+17	Locate 5 seconds for 1000 ℃
							3	7keV	10.2	3.6	1.00E+13	9.80E+18	XX
4	7keV	10.2	3.6	1.00E+13	9.80E+18	Locate 5 seconds for 1000 ℃
							5	7keV	10.2	3.6	1.00E+14	9.80E+19	XX
6	7keV	10.2	3.6	1.00E+14	9.80E+19	Locate 5 seconds for 1000 ℃
							7	20keV	20.3	7.2	2.00E+12	9.85E+17	XX
8	20keV	20.3	7.2	2.00E+12	9.85E+17	Locate 5 seconds for 1000 ℃
							9	20keV	20.3	7.2	2.00E+13	9.85E+18	XX
10	20keV	20.3	7.2	2.00E+13	9.85E+18	Locate 5 seconds for 1000 ℃
							11	20keV	20.3	7.2	2.00E+14	9.85E+19	XX
12	20keV	20.3	7.2	2.00E+14	9.85E+19	Locate 5 seconds for 1000 ℃
							13	35keV	30.6	10.8	3.00E+12	9.80E+17	XX
14	35keV	30.6	10.8	3.00E+12	9.80E+17	Locate 5 seconds for 1000 ℃
							15	35keV	30.6	10.8	3.00E+13	9.80E+18	XX
16	35keV	30.6	10.8	3.00E+13	9.80E+18	Locate 5 seconds for 1000 ℃
							17	35keV	30.6	10.8	3.00E+14	9.80E+19	XX
18	35keV	30.6	10.8	3.00E+14	9.80E+19	Locate 5 seconds for 1000 ℃
							19	50keV	40.6	13.9	4.00E+12	9.85E+17	XX
20	50keV	40.6	13.9	4.00E+12	9.85E+17	Locate 5 seconds for 1000 ℃
							21	50keV	40.6	13.9	4.00E+13	9.85E+18	XX
22	50keV	40.6	13.9	4.00E+13	9.85E+18	Locate 5 seconds for 1000 ℃
							23	50keV	40.6	13.9	4.00E+14	9.85E+19	XX
24	50keV	40.6	13.9	4.00E+14	9.85E+19	Locate 5 seconds for 1000 ℃

Table 3

As described, the following principle of activation dopant properties portrayal technology is to measure near the light-reflected signal that takes place transition between strong band in the semiconductor tape structure.For approximately corresponding to 10 ¹⁸The space charge field that brings out of the F=430kV/cm of the carrier density that the pumping of/cc is brought out, Figure 11 is illustrated in SiE ₁Near the PR signal of the calculating the light absorption.Bring out this carrier density (Opsal, 1985) routinely in the surveillance application of injecting in enormous quantities.As shown in figure 11, on the wavelength coverage of about 360-380nm, the amplitude of this signal is very big.In fact, the amplitude of PR signal is injected at least two orders of magnitude (Opsal, 1985) greatly that surveillance obtains than having now.In addition, as follows, can use activation dopant properties portrayal technology to distinguish and measure activation adulterant in the Si transistor channel, can not realize this application and existing system is verified.

In order to understand the effect of implant damage on the PR signal, need estimate the Seraphin coefficient once more.It is the reason that causes the linear optics response of material that damage distributes, and has therefore measured as of injection itself in history and has used.In order to illustrate, consideration is at the Seraphin coefficient of the Si of the implant damage at 633nm wavelength place.This is the wavelength (Opsal, 1985) that common injection in enormous quantities monitors the PR system.To leave in the silicon any important optical signature far owing to survey the position of wavelength, and therefore light-reflected signal directly takes place the modulation from (Drude) carrier density.For the wavelength of 633nm, have only the variation in the real part of dielectric function to be only important.Therefore, we have Δ R/R ≌ α Δ ε ₁, wherein all membrane stack information are included among the α.In order to calculate

We at first can obtain the analysis expression of R according to the thickness of the refractive index of affected layer, substrate and affected layer.This can also be undertaken by numerical approach, and carries out for any angle under incident or the polarization conditions.Then can be with respect to the real part of dielectric function in number to the R differential and constitute α.Usually, the Seraphin coefficient can vibrate with the cycle of 4 π nd/ λ, and wherein n is the refractive index on the affected layer, and d is that the thickness and the λ of affected layer surveys beam wavelength.Cycle is depended on the optical path length of light in material, so also depend on incident angle.In addition, come damped oscillation by the absorption degree of depth of light.Yet, be the bigger wavelength place of transparency for normal incidence with at Si, these considerations are unessential.Figure 12 illustrates the detection wave beam for 633nm, and the Seraphin coefficient is to the dependence of the affected layer degree of depth and damage fragment.The upper, middle and lower curve corresponds respectively to 10%, 30% and 50% amorphization of input horizon.Made the cycle of the curve of these cosine shapes accord with the trial of obtaining junction depth sensitivity in the past.Yet, in practice, the junction depth dependence of the Δ R/R in being included in α can not be included in Δ ε ₁In dose dependent when separating, the 633nm detector makes the about 15nm of loss of sensitivity or the littler injection degree of depth.Especially, increasing simultaneously the injection degree of depth and dosage can cause the 633nm detectable signal not change.This is an existing invalid reason of instrument in the junction depth technology controlling and process.In addition, existing instrument is subjected to the severe challenge that low dosage is measured because they depend on the Drude charge carrier discrete in to the sensitivity of intrinsic little variation.

Further specify to consider the Seraphin coefficient of the 375nm wavelength implant damage Si of place.Wavelength hereto, the real part of dielectric function and the variation of imaginary part are important.Therefore, when comprising membrane stack information among definite Δ R/R, we must consider α and β.At 375nm wavelength place, the absorption degree of depth in the silicon is δ ≌ 22.6nm.Absorb the degree of depth that the degree of depth is provided with the PR response, therefore be provided with a zone, this zone is for knowing that the membrane stack effect on the PR signal is important.This means that for surface film thickness greater than 22.6nm, the detection wave beam of 375nm becomes following membrane structure insensitive soon.Figure 13 illustrates the dependence of the Seraphin factor alpha of 375nm wave beam to the affected layer degree of depth and damage fragment.The upper, middle and lower curve corresponds respectively to the damage of 10%, 30% and 50% amorphization.The damping of the curve of the cosine shape that is caused by the absorption at this wavelength place is conspicuous.Show this wavelength in the short oscillation period of the Seraphin coefficient of 375nm probing wave strong point and will show that the sensitivity to junction depth drops to about 10nm or following (having precedence over the 633nm wavelength detector).Figure 14 illustrates the dependence of the Seraphin factor beta of 375nm wave beam to the affected layer degree of depth and damage fragment.The upper, middle and lower curve corresponds respectively to 10%, 30% and 50% amorphization.

For prove the ability of activation dopant properties portrayal technology, be used in have 45 ° of incident angles, the pumping on same straight line and detection wave beam dispose the PR device.Pumping and detection wavelength are respectively 845nm and 374nm.With the direct modulated pumping laser intensity of 2MHz square wave that produces by lock-in amplifier.Pumping laser intensity is about 15mW.Use achromatic micro objective to make pumping and detector on same straight line be focused into about 6.5 a microns point of diameter.For these conditions, the carrier density that pumping produces than the employed numerical value of traditional system in enormous quantities to two orders of magnitude when young, or≤1 * 10 ¹⁶/ cc.Yet, increase the 374nm detector sensitivity widely and easily compensated the pump intensity that this has reduced, cause the signal level suitable with the level of system in enormous quantities.Figure 15 illustrates wafer #2, the #4 PR signal with #6.These wafers have 7 identical money electron-volt energy As and inject, and target is to form a knot at 10nm degree of depth place.Wafer #2 receives 1 * 10 ¹²/ cm ²Dosage, wafer #4 receives 1 * 10 ¹³/ cm ²Dosage, and wafer #8 receives 1 * 10 ¹⁴/ cm ²Dosage.Each wafer is accepted equal annealing, and expection can make each wafer activate fully.From wafer #2 to #6, the PR signal | the modulus of Δ R/R| is from ≈ 3 * 10 ^-6Rise to ≈ 3 * 10 ^-5, or an order of magnitude of about amplitude.This has showed the junction depth for 10nm, and two decimal dosage variations cause an about decimal signal to change.Therefore, for the extremely shallow junction depth that requires in the manufacturing process future, the PR technology has been showed the superior sensitivity to the dosage in the wafer of annealing.Can also see that data can highly be reproduced: the data point after being written into and unloading almost can be reproduced mutually definitely.The absolute measurement precision of PR signal is ≈ 5 * 10 ^-7Figure 16,17 and 18 illustrates for bigger injection energy and similarly increases signal with dosage.Figure 16 illustrates the PR signal of wafer #8, #10 and #12.These wafers have 20 identical keV energy As and inject, and target is to form a knot at 20nm degree of depth place.Wafer #8 receives 2 * 10 ¹²/ cm ²Dosage, wafer #10 receives 2 * 10 ¹³/ cm ²Dosage, and wafer #12 receives 2 * 10 ¹⁴/ cm ²Dosage.Each wafer is accepted equal annealing, and expection can make each wafer activate fully.To #12, the modulus of PR signal is from ≈ 4 * 10 from wafer #8 ^-6Rise to ≈ 2.6 * 10 ^-5, or an order of magnitude of about amplitude.This has showed once more in the wafer through annealing of the extremely shallow junction depth of 20nm, to the good sensitivity of dosage and good signal reproduction.Figure 17 illustrates the PR signal of wafer #14, #16 and #18.These wafers have 35 identical keV energy and inject, and target is to form a knot at 30nm degree of depth place.Wafer #14 receives 3 * 10 ¹²/ cm ²Dosage, wafer #16 receives 3 * 10 ¹³/ cm ²Dosage, and wafer #18 receives 3 * 10 ¹⁴/ cm ²Dosage.Each wafer is accepted equal annealing, and expection can make each wafer activate fully.From wafer #14 to #18, the PR signal | the modulus of Δ R/R| is from ≈ 5 * 10 ^-6Rise to ≈ 3 * 10 ^-5, or an order of magnitude of about amplitude.This has showed once more in the wafer through annealing of the extremely shallow junction depth of 30nm, to the good sensitivity of dosage and good signal reproduction.Figure 18 illustrates the PR signal of wafer #20, #22 and #24.These wafers have 50 identical keV energy and inject, and target is to form a knot at 40nm degree of depth place.Wafer #20 receives 4 * 10 ¹²/ cm ²Dosage, wafer #22 receives 4 * 10 ¹³/ cm ²Dosage, and wafer #24 receives 4 * 10 ¹⁴/ cm ²Dosage.Each wafer is accepted equal annealing, and expection can make each wafer activate fully.To #24, the modulus of PR signal is from ≈ 4 * 10 from wafer #20 ^-6Rise to ≈ 4 * 10 ^-5, or an order of magnitude of about amplitude.This has showed once more in the wafer through annealing of the extremely shallow junction depth of 40nm, to the good sensitivity of dosage and good signal reproduction.

As previously mentioned, expectation PR signal is with the junction depth sinusoidal variations.Figure 19 illustrates the modulus as the PR signal function of junction depth, each wafer through annealing.Corresponding to about 1 * 10 ¹⁸/ cc, 1 * 10 ¹⁹/ cc and 1 * 10 ²⁰The constant doping density of/cc, among Figure 19 in three " OK " each show so sinusoidal variations.Calibrate by the least density row to Figure 19, Figure 20 further shows this characteristic of the PR data of lowest dose level.

Figure 21 illustrates the PR signal of wafer #1, #3 and #5.These " only inject " wafer less than annealing.They have 7 identical keV energy As injects, and target is to form a knot at 10nm degree of depth place.Wafer #1 receives 1 * 10 ¹²/ cm ²Dosage, wafer #3 receives 1 * 10 ¹³/ cm ²Dosage, and wafer #5 receives 1 * 10 ¹⁴/ cm ²Dosage.From wafer #1 to #5, the PR signal | the modulus of Δ R/R| is from ≈ 1.6 * 10 ^-5Be reduced to ≈ 3 * 10 ^-6, or an order of magnitude of about amplitude.With from through the wafer view of annealing to performance opposite with increase this situation that dosage reduces signal be since inject the damage that causes less crystal SiE ₁The sharpness of interband transition energy causes.For the extremely shallow junction depth of 10nm, this shows the good PR sensitivity of " only injecting " wafer to dosage.Figure 22,23 and 24 illustrates with bigger injection energy and similarly reduces signal with dosage.Figure 22 illustrates the PR signal of wafer #7, #9 and #11.These wafers have 20 identical keV energy As and inject, and target is to form a knot at 20nm degree of depth place.Wafer #7 receives 2 * 10 ¹²/ cm ²Dosage, wafer #9 receives 2 * 10 ¹³/ cm ²Dosage, and wafer #11 receives 2 * 10 ¹⁴/ cm ²Dosage.Each wafer all is " only inject " and not annealing.From wafer #7 to #11, the PR signal | the modulus of Δ R/R| is from ≈ 1.2 * 10 ^-5Be reduced to ≈ 3 * 10 ^-6, about 4 times.For the extremely shallow junction depth of 20nm, this shows the good PR sensitivity of " only injecting " wafer to dosage.Figure 23 illustrates the PR signal of wafer #13, #15 and #17.These wafers have 35 identical keV energy As and inject, and target is to form a knot at 30nm degree of depth place.Wafer #13 receives 3 * 10 ¹²/ cm ²Dosage, wafer #15 receives 3 * 10 ¹³/ cm ²Dosage, and wafer #17 receives 3 * 10 ¹⁴/ cm ²Dosage.Each wafer all is " only inject " and not annealing.From wafer #13 to #17, the PR signal | the modulus of Δ R/R| is from ≈ 1 * 10 ^-5Be reduced to ≈ 2 * 10 ^-6, about 5 times.For the extremely shallow junction depth of 30nm, this shows the good PR sensitivity of " only injecting " wafer to dosage once more.Figure 24 illustrates the PR signal of wafer #19, #21 and #23.These wafers have 50 identical keV energy As and inject, and target is to form a knot at 40nm degree of depth place.Wafer #19 receives 4 * 10 ¹²/ cm ²Dosage, wafer #21 receives 4 * 10 ¹³/ cm ²Dosage, and wafer #23 receives 4 * 10 ¹⁴/ cm ²Dosage.Each wafer all is " only inject " and not annealing.From wafer #19 to #23, the PR signal | the modulus of Δ R/R| is from ≈ 6 * 10 ^-6Be reduced to ≈ 2 * 10 ^-6, about 3 times.For the extremely shallow junction depth of 40nm, this shows the good PR sensitivity of " only injecting " wafer to dosage once more.

Figure 25 illustrates the modulus that injects the PR signal of wafer as each As of the function of junction depth.By following each " OK " among Figure 25, can see target doping density (1 * 10 ¹⁸/ cc, 1 * 10 ¹⁹/ cc and 1 * 10 ²⁰/ cc) each group is followed the sinusoidal variations that is subjected to damping.Observe with the sensitivity of the variation of injecting the degree of depth and reduce dosage, total this be since in the affected layer crystallographic reduce and the combination of bigger absorption causes.

Therefore, as disclosing here, the light of the adulterant of strain and activation-reflection characteristic depicting method provides and has distinguished and measured strain and the new and accurate ability that activates adulterant in the nanometer semiconductor structure in the semiconductor structure, and when so carrying out, broken away from the traditional concept and the design of prior art in fact.

When to the further discussion of the use-pattern of this announcement and operation, from above-mentioned explanation, identical content is conspicuous.Therefore, no longer provide further discussion about use-pattern and operation.

So, with respect to above-mentioned explanation, be appreciated that, think that the magnitude relationship that discloses the best partly comprises the variation in size, material, shape, form, function and mode of operation, assembling and the use, these are to understand easily and conspicuous for those of ordinary skill in the art, be intended to make shown in the accompanying drawing with instructions in all equivalent relations of describing all be included in this announcement.

Therefore, think that top content is only in order to illustrate the principle of this announcement.In addition, because those of ordinary skill in the art make many modifications and variations easily, be not subjected to the restriction of shown and described precise structure and operation so do not wish this announcement, therefore, can seek help from all the suitable modifications and the equivalent that drop in this announcement scope.

List of references

American documentation literature:

6,963,402 11/2005 Chism...................356/367

6,195,166 2/2001 Gray....................356/477

4,931,132 6/1990 Aspnes.................156/601

Other publication:

＂ Dynamics of the plasma and thermal waves in surface-modifiedsemiconductors (invited), ＂ Alex Salnick and Jon Opsal, Rev.Sci.Inst.74,545 (2003).

＂ Nondestructive profile measurements of annealed shallow implants, ＂ P.Borden waits the people, and J.Vac.Sci.Technol.B 18,602 (2000).

＂ Dielectric response of strained and relaxedSi _1-x-yGe _xC _yAlloys grown bymolecular beam epitaxy on Si (001), people such as ＂ R.Lange, J.Appl.Phys.80,4578 (1996).

＂ Optical functions of ion-implanted, laser-annealed heavily doped silicon, people such as ＂ G.E.Jellison, Phys.Rev.B 52,14607 (1995).

＂ Modulation Spectroscopy of Semiconductors and SemiconductorMicrostructures, ＂ F.H.Pollack, at the semiconductor handbook second volume 527-635 page or leaf (North-Holland, Amsterdam, 1994) that M.Balkanski edited.

＂ Photo-reflectance characterization of GaAs a function of temperature, carrier concentration, and near-surface electric field, people such as ＂ A.B adakhshan, J.Vac.Sci.Technol.B 11,169 (1993).

＂ Photo-reflectance study of photo voltage effects in GaAs diode structures, ＂ V.M.Airaksinen and H.K.Lipsanen, Appl.Phys.Lett.60,2110 (1992).

＂ Photo-reflectance studies of silicon films on sapphire, ＂ A.Giordana and R.Glosser, J.Appl.Phys.69,3303 (1991).

＂ Correlation between the photo-reflectance response at E ₁And carrierconcentration in n-and p-GaAs, ＂ A.Badakhshan, R.Glosser, and S.Lambert, J.Appl.Phys.69,2525 (1991).

＂ Dynamics of photo-reflectance from undoped GaAs, people such as ＂ H.Shen, Appl.Phys.Lett.59,321 (1991).

＂ Photo-reflectance study of surface Fermi level in GaAs and GaAlAs, people such as ＂ H.Shen, Appl.Phys.Lett.57,2118 (1990).

＂ Generalized Franz-Keldysh theory of electromodulation, ＂ H.Shen and F.H.Pollak, Phys.Rev.B42,7097 (1990).

＂ Photo-reflectance study of Fermi level changes in photowashed GaAs, ＂ H.Shen, F.H.Pollak, and J.M.Woodall, J.Vac.Sci.Technol.B 8,413 (1990).

＂ Electric field distributions in a molecular-beam epitaxyGa _0.83Al _0.17As/GaAs/GaAs structure using photo-reflectance, ＂ Ff.Shen, F.H.Pollak, J.M.Woodall, and R.N.Sacks, J.Vac.Sci.Technol.B7,804 (1989).

＂ Thermal and plasma wave depth profiling in silicon, ＂ Jon Opsal and AllanRosencwaig, Appl.Phys.Lett.47,498 (1985).

＂ Photo-reflectance characterization of interband transitions in GaAs/AlGaAsmultiple quantum wells and modulation-doped heterojunctions, people such as ＂ O.J.Glembocki, Appl.Phys.Lett.46,970 (1985).

＂ Modulation Spectroscopy, ＂ D.Aspnes is in the 109th page (North-Holland, Amsterdam, 1980) of semiconductor handbook second volume that M.Balkanski edited.

＂Photo-reflectance Line Shape at the Fundamental Edge in Ultrapure GaAs，＂J.L.Shay，Phys.Rev.B 2，803(1970).

＂ Reflectance Modulation by the Surface Field in GaAs, ＂ R.E.Nahory and J.L.Shay, Phys.Rev, Lett.21,1569 (1968).

＂ Band-Structure Analysis from Electro-Reflectance Studies, ＂ B.O.Seraphin and N.Bottka, Phys.Rev.145,628 (1966).

＂Optical Field Effect in Silicon，＂B.O.Seraphin，Phys.Rev.140，A 1716(1965).

＂ Optical-Field Effect on Thresholds, Saddle-Point Edges, and Saddle-PointExcitons, ＂ J.C.Philips and B.O.Seraphin, Phys.Rev.Lett.15,107 (1965).

＂ Field Effect of the Reflectance in Silicon, ＂ B.O.Seraphin and N.Bottka, Phys.Rev.Lett.15,104 (1965).

Claims (19)

1. method that is used for determining the physical property of semiconductor structure, described method comprises the following steps:

A) zone on the surface of the pumping laser wave beam irradiation semiconductor structure of use amplitude modulation(PAM), the pumping wave beam comprises its energy at least one wavelength greater than the minimum interband transition energy of the semiconductor material in the semiconductor structure, thereby bring out the time cycle property variation of the electric density in the semiconductor structure, so that the electric field in the semiconductor structure obtains the modulation of time cycle property, and wherein the semiconductor material in the semiconductor structure stands the time cycle property modulation of interband transition energy;

B) use the independently part in exploring laser light wave beam irradiating step described zone a), survey wave beam and comprise at least one wavelength, and be suitable for writing down the variation of bringing out that occurs near the semiconductor material optic response of interband transition energy near the interband transition energy of the semiconductor material in the semiconductor structure;

C) record is surveyed light from the interchange through reflection of the irradiation of semiconductor structure, wherein exchange survey light comprise be called as light-reflected signal, the semiconductor material optic response bring out variation; And

D) use step a), b), c) in the information of collecting determine the physical property of semiconductor structure.

2. the method for claim 1 is characterized in that, comes the monitoring physical strain according to a calibration curve of determining by experience, and this calibration curve associates the symbol of normalized light-reflected signal and amplitude and physical strain.

3. the method for claim 1 is characterized in that, monitors described physical strain according to relational expression Δ R/R=m χ+b, wherein Δ R/R is normalized light-reflected signal, χ is a physical strain, and m is the linearly dependent coefficient of determining by experience, and b is the skew of determining by experience.

4. the method for claim 1 is characterized in that, monitors electric density according to a calibration curve of determining by experience, and this calibration curve associates normalized light-reflected signal and electric density.

5. the method for claim 1 is characterized in that, according to relational expression Δ R/R=mN _e+ b monitors electric density, and wherein Δ R/R is normalized light-reflected signal, N _eBe electric density, m is the linearly dependent coefficient of determining by experience, and b is the skew of determining by experience.

6. the method for claim 1 is characterized in that, according to relational expression Δ R/R=mF ²+ b monitors electric field, and wherein Δ R/R is normalized light-reflected signal, and F is an electric field, and m is the linearly dependent coefficient of determining by experience, and b is the skew of determining by experience.

7. the method for claim 1 is characterized in that, monitors the electric charge depth profile according to a calibration curve of determining by experience, and this calibration curve associates normalized light-reflected signal and electric charge depth profile.

8. the method for claim 1, it is characterized in that, described detecting laser is a Wavelength tunable laser, be used for providing the approaching a plurality of wavelength of at least one interband transition energy with the optic response of semiconductor material, and wherein use to exchange and survey position, amplitude, spectral width and/or the spectral shape that optical wavelength information is determined the interband transition energy.

9. the method for claim 1, it is characterized in that, described semiconductor structure comprises insulant semiconductor-on-insulator membrane structure, and the wavelength of wherein selecting the pumping wave beam with provide less than or be equivalent to the absorption degree of depth of thickness of the semiconductor layer of electric insulation, therefore be suitable for bringing out the time cycle property variation of the electric density in the semiconductor layer of insulation.

10. the method for claim 1, it is characterized in that, described semiconductor structure comprises the semiconductor material of electric insulation, and the wavelength of wherein selecting the pumping wave beam with provide less than or be equivalent to the absorption degree of depth of the physics size of semiconductor material, therefore be suitable for bringing out the time cycle property variation of the electric density in the semiconductor material of insulation.

11. the method for claim 1 is characterized in that, determines the variation as the light-reflected signal of the function of pumping wave beam intensity.

12. be used to detect the device of the physical property of semiconductor structure, comprise:

Semiconductor structure with reflecting surface;

The pump laser system, it provides the laser beam of the amplitude modulation(PAM) of modulating frequency in 100kHz arrives the 50MHz scope, with about 5mW or bigger luminous power work, and comprise the wavelength of at least one its energy greater than the minimum interband transition energy of the semiconductor material in the semiconductor structure;

The detecting laser system, it provides the continuous wave laser wave beam, with about 10mW or littler luminous power work, and comprises at least one wavelength near the interband transition energy of the semiconductor material in the semiconductor structure;

Optical system, it focuses on diameter on the semiconductor structure surface to laser beam effectively is on 50 microns or the littler confocal spot, and from the sample detection light reflected separately and be directed on the photelectric receiver;

Photelectric receiver, it is configured to produce the electric current that is directly proportional with input intensity;

The lockin signal detection system connects it with the output of record photelectric receiver; And

The computing machine that has measurement and system controlling software.

13. device as claimed in claim 12 is characterized in that, described semiconductor structure comprises silicon substrate on the insulant, and the pump laser wavelength is about 500nm or littler.

14. device as claimed in claim 12 is characterized in that, described detecting laser wavelength is about 375nm.

15. device as claimed in claim 12 is characterized in that, described detecting laser is an external cavity formula Wavelength tunable laser, it provide with semiconductor structure in the approaching a plurality of wavelength of interband transition energy of semiconductor material.

16. device as claimed in claim 12 is characterized in that, by using the dichromatism optical splitter, makes pumping laser wave beam and exploring laser light wave beam conllinear.

17. device as claimed in claim 16 is characterized in that, by using achromatic object lens, makes at the pumping laser wave beam on the same straight line and exploring laser light wave beam to focus on jointly on the zone on surface of semiconductor structure.

18. device as claimed in claim 12 is characterized in that, by using color filter, pump light is separated from the interchange detection light of reflection.

19. device as claimed in claim 12 is characterized in that, with the inner reference signal that produces of phase-locked detection system, directly modulated pumping laser intensity.

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