JP2536677B2 - Solar cell manufacturing method - Google Patents
Solar cell manufacturing methodInfo
- Publication number
- JP2536677B2 JP2536677B2 JP2206259A JP20625990A JP2536677B2 JP 2536677 B2 JP2536677 B2 JP 2536677B2 JP 2206259 A JP2206259 A JP 2206259A JP 20625990 A JP20625990 A JP 20625990A JP 2536677 B2 JP2536677 B2 JP 2536677B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- polycrystalline
- film
- solar cell
- substrate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/545—Microcrystalline silicon PV cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/546—Polycrystalline silicon PV cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/548—Amorphous silicon PV cells
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- Photovoltaic Devices (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、低コストで、高いエネルギー変換効率を
実現する太陽電池の製造方法に関するものである。TECHNICAL FIELD The present invention relates to a method for manufacturing a solar cell that realizes high energy conversion efficiency at low cost.
第４図（ａ）〜（ｇ）は、例えばThe Conference Rec
ord of the 18th IEEE Photvoltaic Specialists Confe
rence−1985,p192−197に記載された太陽電池の製造方
法の一例を工程順に示す断面図である。4 (a) to (g) show, for example, The Conference Rec.
ord of the 18th IEEE Photvoltaic Specialists Confe
It is sectional drawing which shows an example of the manufacturing method of the solar cell described in rence-1985, p192-197 in process order.
この図において、１は、例えばp+型Siからなる基板で
ある（第４図（ａ））。In this figure, 1 is a substrate made of, for example, p + type Si (FIG. 4 (a)).
この基板１上に、例えば熱CVD法によりSiO2からなる
拡散防止膜２を形成する。拡散防止膜２は基板１からこ
の後形成する活性層11へ不純物が拡散するのを防ぐほ
か、後述するように光の裏面反射層としても機能する
（第４図（ｂ））。On this substrate 1, to form a diffusion preventing film 2 made of SiO 2, for example, by a thermal CVD method. The diffusion prevention film 2 prevents diffusion of impurities from the substrate 1 to the active layer 11 to be formed later, and also functions as a back surface reflection layer of light as described later (FIG. 4 (b)).
拡散防止膜２は絶縁物であり、このままでは裏面側の
電気的接続がとれないため、拡散防止膜２を、例えばエ
ッチングにより間隔400μm,直径200μｍの開口部３を形
成して選択的に基板１を露出させる（第４図（ｃ））。The diffusion prevention film 2 is an insulator, and the electrical connection on the back surface side cannot be made as it is. Therefore, the diffusion prevention film 2 is selectively formed by, for example, etching to form openings 3 having a spacing of 400 μm and a diameter of 200 μm. Is exposed (FIG. 4 (c)).
拡散防止膜２上および開口部３の基板１上に、例えば
Sn−Si液相成長法によりp-型多結晶Si薄膜4,n+型多結晶
Si薄膜５を順次形成する（第４図（ｄ））。On the diffusion prevention film 2 and the substrate 1 of the opening 3, for example,
P - type polycrystalline Si thin film by n-Si liquid phase epitaxy 4, n + type polycrystalline
The Si thin film 5 is sequentially formed (FIG. 4 (d)).
n+型多結晶Si薄膜５上に、例えばスパッタ蒸着法によ
りITO（インジウムとスズの酸化物）からなる反射防止
膜兼透明導電膜６を形成する（第４図（ｅ））。On the n + -type polycrystalline Si thin film 5, the antireflection film / transparent conductive film 6 made of ITO (oxide of indium and tin) is formed by, for example, a sputter deposition method (FIG. 4 (e)).
反射防止膜兼透明導電膜６上に、例えば電子ビーム蒸
着法によりAgからなる表面金属電極７をパターン形成す
る（第４図（ｆ））。A surface metal electrode 7 made of Ag is patterned on the antireflection film / transparent conductive film 6 by, for example, an electron beam evaporation method (FIG. 4 (f)).
基板１の裏面上に、例えば電子ビーム蒸着法によりAg
からなる裏面金属電極８を形成する（第４図（ｇ））。Ag on the back surface of the substrate 1 by, for example, electron beam evaporation method.
A back surface metal electrode 8 made of is formed (FIG. 4 (g)).
以上の工程により太陽電池９が構成される。裏面電極
10は基板１および裏面金属電極８により構成され、光電
変換をおこなう活性層11は、p-型多結晶Si薄膜４および
n+型多結晶Si薄膜５により構成され、さらに、表面電極
12は反射防止膜兼透明導電膜６および表面金属電極７に
より構成されている。The solar cell 9 is configured by the above steps. Back electrode
Reference numeral 10 is composed of the substrate 1 and the back surface metal electrode 8, and the active layer 11 for photoelectric conversion is composed of the p − -type polycrystalline Si thin film 4 and
It is composed of n + type polycrystalline Si thin film 5 and further has a surface electrode
Reference numeral 12 is composed of an antireflection film / transparent conductive film 6 and a surface metal electrode 7.
次に、動作について説明する。 Next, the operation will be described.
太陽電池９に入射し、活性層11で吸収された光は、そ
の光エネルギーにより電子と正孔の励起キャリアを生成
する。活性層11内に形成されているpn接合により、励起
されたキャリアのうち電子はn+型多結晶Si薄膜５へ流れ
込み、逆に正孔はp-型多結晶Si薄膜４へ流れ込む。これ
により光エネルギーは電気エネルギーへと変換され、表
面電極12、あるいは裏面電極10を通じて外部へ取り出さ
れる。反射防止兼透明導電膜６は表面の光反射を抑え、
拡散防止膜２は活性層11を透過した光を反射して、いず
れも活性層11へ有効な光吸収がなされるように機能して
いる。The light incident on the solar cell 9 and absorbed by the active layer 11 generates excited carriers of electrons and holes due to the light energy. Due to the pn junction formed in the active layer 11, electrons of the excited carriers flow into the n + -type polycrystalline Si thin film 5, and conversely holes flow into the p − -type polycrystalline Si thin film 4. As a result, the light energy is converted into electric energy and is extracted to the outside through the front surface electrode 12 or the back surface electrode 10. The antireflection and transparent conductive film 6 suppresses light reflection on the surface,
The diffusion prevention film 2 functions to reflect the light transmitted through the active layer 11 and effectively absorb the light into the active layer 11.
従来の太陽電池の製造方法では、絶縁膜である拡散防
止膜２上および開口部３の基板１上に直接活性層11を形
成していた。しかし、開口部３の基板１上に比べて絶縁
膜上では活性層11である半導体が結晶成長しづらく、活
性層11を膜として形成するためには開口部３を大きく、
高密度で形成する必要があった。ところが、基板１と活
性層11が直接接触している開口部３では、活性層11の形
成時の高温下で基板１と活性層11の間で不純物の拡散が
おこる。基板材料に安価な低純度のものを使用した場
合、これらはFe,Cuなど半導体物性に悪影響を及ぼす金
属不純物を大量に含んでいるため、太陽電池の特性を悪
くする原因となる。逆に、高純度のものを用いると、基
板コストが高くなってしまう、といった問題点があっ
た。また、この構造では基板１は裏面電極10の一部とし
て機能するため導電性が必要となり、基板材料の選択の
幅を狭め、これも低コスト化を阻害する要因になってい
た。In the conventional solar cell manufacturing method, the active layer 11 is formed directly on the diffusion prevention film 2 which is an insulating film and on the substrate 1 having the opening 3. However, the semiconductor that is the active layer 11 is less likely to undergo crystal growth on the insulating film than on the substrate 1 of the opening 3, and the opening 3 is large in order to form the active layer 11 as a film.
It had to be formed with high density. However, in the opening 3 where the substrate 1 and the active layer 11 are in direct contact with each other, impurities are diffused between the substrate 1 and the active layer 11 under high temperature when the active layer 11 is formed. When inexpensive and low-purity substrate materials are used, these contain a large amount of metallic impurities such as Fe and Cu, which adversely affect the physical properties of the semiconductor, and thus cause deterioration of the characteristics of the solar cell. On the other hand, if a high-purity material is used, the cost of the substrate will increase, which is a problem. Further, in this structure, since the substrate 1 functions as a part of the back surface electrode 10, conductivity is required, which narrows the selection range of the substrate material, which is also a factor that hinders cost reduction.
さらに、従来例に示す構造のように、Si/SiO2/Si界面
による裏面からの光反射では反射率が十分でなく、活性
層11への光の吸収が有効に行われないので、太陽電池の
高効率化が望めない、といった問題点があった。また、
開口部３の占める割合が大きく、すなわち拡散防止膜２
の占める部分の割合が小さくなると、それはますます顕
著になる。Furthermore, as in the structure shown in the conventional example, the reflectance is not sufficient for light reflection from the back surface by the Si / SiO 2 / Si interface, and the absorption of light into the active layer 11 is not effectively performed, so that the solar cell There was a problem that it could not be expected to be highly efficient. Also,
The opening 3 occupies a large proportion, that is, the diffusion prevention film 2
It becomes more and more prominent as the proportion of the area occupied by becomes smaller.
この発明は、上記のような問題点を解決するためにな
されたもので、活性層の形成が容易で、基板から活性層
への不純物がなく、基板材料に対する制約が少なく、か
つ光エネルギーを有効に電気エネルギーに変換できる低
コストで高品質の太陽電池の製造方法を得ることを目的
とする。The present invention has been made to solve the above problems, and it is easy to form an active layer, there are no impurities from the substrate to the active layer, there are few restrictions on the substrate material, and the light energy is effective. It is an object of the present invention to obtain a low-cost and high-quality solar cell manufacturing method that can convert electric energy into electricity.
この発明に係る太陽電池の製造方法は、第１の支持基
板上に拡散防止膜としてのSiO2膜とアモルファスSi薄膜
とを順次形成し、該アモルファスSi薄膜上にキャップ層
を形成する工程と、次いで、前記アモルファスSi薄膜を
溶融・再結晶化して第１の多結晶Si薄膜を形成する工程
と、次いで前記キャップ層を除去して前記第１の多結晶
Si薄膜を露出させる工程と、次いで前記露出された第１
の多結晶Si薄膜の上に該第１の多結晶Si薄膜を核として
第２の多結晶Si薄膜を成長させる工程と、次いで前記第
２の多結晶Si薄膜の上に該第２の多結晶Si薄膜とは逆導
電型の結晶Si薄膜を形成する工程と、次いで前記結晶Si
薄膜上に表面金属電極を形成する工程と、次いで前記表
面金属電極上に第２の支持基板を貼り付けて、第１の支
持基板上に形成された各層を第２の支持基板により保持
した状態で、前記第１の支持基板を研削または溶解によ
り除去する工程と、次いで前記SiO2膜の少なくとも一部
を溶解により除去し、前記溶融・再結晶化した第１の多
結晶Si薄膜の少なくとも一部を露出させる工程と、次い
で前工程で露出された第１の多結晶Si薄膜に裏面金属電
極を形成する工程とを含むものである。A method for manufacturing a solar cell according to the present invention comprises a step of sequentially forming a SiO 2 film as a diffusion prevention film and an amorphous Si thin film on a first supporting substrate, and forming a cap layer on the amorphous Si thin film. Then, a step of melting and recrystallizing the amorphous Si thin film to form a first polycrystalline Si thin film, and then removing the cap layer to remove the first polycrystalline
Exposing the Si thin film, and then the exposed first
Growing the second polycrystalline Si thin film with the first polycrystalline Si thin film as a nucleus on the polycrystalline Si thin film, and then the second polycrystalline thin film on the second polycrystalline Si thin film. A step of forming a crystalline Si thin film of a conductivity type opposite to that of the Si thin film,
A step of forming a surface metal electrode on the thin film, and then a state in which a second supporting substrate is attached on the surface metal electrode and each layer formed on the first supporting substrate is held by the second supporting substrate. And then removing the first supporting substrate by grinding or melting, and then removing at least a part of the SiO 2 film by melting, and at least one of the melted and recrystallized first polycrystalline Si thin films. And a step of forming a back surface metal electrode on the first polycrystalline Si thin film exposed in the previous step.
この発明においては、拡散防止膜には開口部を設けず
に活性層を形成するので、基板から活性層への不純物拡
散を小さく抑えられる。In the present invention, since the active layer is formed without providing the opening in the diffusion prevention film, the diffusion of impurities from the substrate into the active layer can be suppressed to a small level.
また、その後に基板および拡散防止膜を除去して、活
性層と裏面電極とを接続させるようにしたので、太陽電
池の機械的強度の保持および裏面電極の一部から、製造
工程の途中までの太陽電池の機械的強度の保持へと、基
板の役割は大幅に軽減される。Further, after that, the substrate and the diffusion prevention film were removed to connect the active layer and the back electrode, so that the mechanical strength of the solar cell was maintained and a part of the back electrode was used up to the middle of the manufacturing process. The role of the substrate in maintaining the mechanical strength of the solar cell is greatly reduced.
以下、この発明の一実施例を図面について説明する。 An embodiment of the present invention will be described below with reference to the drawings.
第１図（ａ）〜（ｊ）はこの発明による太陽電池の製
造方法の一実施例を工程順に示す断面図である。1 (a) to 1 (j) are sectional views showing an embodiment of a method for manufacturing a solar cell according to the present invention in the order of steps.
この図において、１〜12は第４図において同一符号で
示した部分と同一または相当する部分である。ただし、
１はその役割に若干の違いが生じているため、第１の支
持基板と呼ぶことにする。13は第２の支持基板であり、
この実施例ではガラスが用いられている。また、14はp-
型アモルファスSi薄膜、15はキャップ層、16は成長核
層、17は充填剤である。In this figure, 1 to 12 are the same or corresponding parts as those shown by the same reference numerals in FIG. However,
Since 1 has a slight difference in its role, it will be referred to as a first supporting substrate. 13 is a second support substrate,
Glass is used in this embodiment. In addition, 14 p -
-Type amorphous Si thin film, 15 is a cap layer, 16 is a growth nucleus layer, and 17 is a filler.
まず、例えば金属級Si粉末を溶融・成形して固化させ
た第１の支持基板１（第１図（ａ））上にCVD法によりS
iO2からなる拡散防止膜２を200nm,p-型アモルファスSi
薄膜14を１μm,SiO2からなるキャップ層15を１μｍに順
次形成する（第１図（ｂ））。First, for example, by a CVD method, S is formed on the first supporting substrate 1 (FIG. 1 (a)) obtained by melting, molding, and solidifying metal-grade Si powder.
The diffusion preventive film 2 made of iO 2 is applied to 200 nm, p - type amorphous Si.
A thin film 14 and a cap layer 15 made of SiO 2 are sequentially formed to a thickness of 1 μm and 1 μm, respectively (FIG. 1 (b)).
次に、p-型アモルファスSi薄膜14をレーザアニール，
ランプアニールあるいはストリップヒータ法などで溶融
・再結晶化し、数10μｍ〜数mmの大粒径p+型多結晶Si薄
膜を形成する。これを成長核層16として用いる。この成
長核層16は２つのSiO2膜ではさまれているため、p-型ア
モルファスSi薄膜14に加えられた熱が逃げにくくなって
溶融が容易になり、大粒径化しやすくなる（第１図
（ｃ））。Next, laser annealing of the p - type amorphous Si thin film 14
It is melted and recrystallized by lamp annealing or strip heater method, etc. to form a large grain size p + -type polycrystalline Si thin film of several 10 μm to several mm. This is used as the growth nucleus layer 16. Since this growth nucleus layer 16 is sandwiched between two SiO 2 films, the heat applied to the p − -type amorphous Si thin film 14 is difficult to escape, melting is facilitated, and the grain size is easily increased (first Figure (c)).
次に、キャップ層15をHF（弗酸）処理によりエッチン
グ除去して成長核層16を露出させる（第１図（ｄ））。Then, the cap layer 15 is removed by etching with HF (hydrofluoric acid) to expose the growth nucleus layer 16 (FIG. 1 (d)).
この上にSn−Si液相成長法によりp-型多結晶Si薄膜４
を30μｍ形成する。成長核層16全面を核として成長する
ため、容易にp-型多結晶Si薄膜４を形成できる。また、
この時点では、第１の支持基板１とp-型多結晶Si薄膜４
と成長核層16とは、間に拡散防止膜２があって直接接し
ていないため、液相成長時の高温でも第１の支持基板１
から活性層11への不純物拡散を抑えることができる（第
１図（ｅ））。On top of this, p - type polycrystalline Si thin film 4 was formed by Sn-Si liquid phase epitaxy.
Is formed to 30 μm. Since the entire surface of the growth nucleus layer 16 is grown as a nucleus, the p − type polycrystalline Si thin film 4 can be easily formed. Also,
At this point, the first supporting substrate 1 and the p − -type polycrystalline Si thin film 4 are
Since the diffusion preventing film 2 is not directly in contact with the growth nucleus layer 16 at the high temperature during the liquid phase growth, the first supporting substrate 1
Impurities can be suppressed from diffusing into the active layer 11 (FIG. 1 (e)).
次に、p-型多結晶Si薄膜４上にn+型微結晶Si薄膜５を
20nmプラズマCVD法により形成し、この上にITOからなる
反射防止膜兼透明導電膜６をスパッタ蒸着法により形成
し、さらにこの上に、Agからなる表面金属電極７を電子
ビーム蒸着法により順次形成する（第１図（ｆ））。Next, the n + type microcrystalline Si thin film 5 is formed on the p − type polycrystalline Si thin film 4.
It is formed by a 20 nm plasma CVD method, an antireflection film / transparent conductive film 6 made of ITO is formed thereon by a sputter deposition method, and a surface metal electrode 7 made of Ag is sequentially formed thereon by an electron beam evaporation method. (FIG. 1 (f)).
さらに、例えばEVA（Ethylene vinyl acetate）から
なる充填剤17を介してガラスからなる第２の支持基板13
を貼り付ける。従来、この工程は太陽電池セル工程の後
のモジュール工程に含まれるものであったが、以下に述
べる第１の支持基板１の除去のため、この実施例ではこ
こでおこなっている（第１図（ｇ））。Further, for example, a second supporting substrate 13 made of glass via a filler 17 made of EVA (Ethylene vinyl acetate).
Paste. Conventionally, this step was included in the module step after the solar cell step, but this step is performed here in this embodiment to remove the first supporting substrate 1 described below (see FIG. 1). (G)).
第２の支持基板13を貼り付けるまでは、機械的強度保
持のため第１の支持基板１は必要であった。しかし、第
２の支持基板13が貼り付けられたことで機械的強度は保
たれるので、第１の支持基板１は必要でなくなる。逆
に、活性層11の裏面側の電気的接続をとるためには、第
１の支持基板１および拡散防止膜２に何らかの処理が必
要である。Until the second supporting substrate 13 was attached, the first supporting substrate 1 was necessary for maintaining the mechanical strength. However, since the second supporting substrate 13 is attached, the mechanical strength is maintained, so that the first supporting substrate 1 is not necessary. On the contrary, in order to establish the electrical connection on the back surface side of the active layer 11, the first support substrate 1 and the diffusion prevention film 2 need some treatment.
そこで、例えば弗酸と硝酸の混酸、水酸化カリウム水
溶液などを用いたエッチング、あるいはラッピングなど
の機械的研削により第１の支持基板１を裏面から除去
し、拡散防止膜２を露出させる（第１図（ｈ））。Therefore, the first support substrate 1 is removed from the back surface by etching using a mixed acid of hydrofluoric acid and nitric acid, an aqueous solution of potassium hydroxide or the like, or mechanical grinding such as lapping to expose the diffusion prevention film 2 (first Figure (h)).
さらに、拡散防止膜２を、例えば弗酸によりエッチン
グ除去し、成長核層16を裏面から露出させる。これによ
り活性層11の裏面側の電気的接触がとれるようになる
（第１図（ｉ））。Further, the diffusion prevention film 2 is removed by etching with, for example, hydrofluoric acid to expose the growth nucleus layer 16 from the back surface. As a result, electrical contact can be established on the back surface side of the active layer 11 (FIG. 1 (i)).
この後、成長核層16の裏面上に、電子ビーム蒸着法に
よりAg膜を蒸着して、裏面金属電極８を形成する（第１
図（ｊ））。Then, an Ag film is vapor-deposited on the back surface of the growth nucleus layer 16 by an electron beam vapor deposition method to form a back-side metal electrode 8 (first).
Figure (j)).
この実施例の裏面金属電極８は、従来例で拡散防止膜
２が果たしていた反射層としての機能を兼ねている。１
μｍの波長の光で考えた場合、計算によると従来例のよ
うなSi/SiO2/Si界面による反射では最大0.49の反射率し
か達成できないのに対し、この実施例ではSi/Ag界面に
よる反射であるため、0.95とほぼ完全な反射率が達成で
き、活性層11へのより有効な光吸収を図ることができ
る。The back surface metal electrode 8 of this embodiment also has a function as a reflection layer which the diffusion prevention film 2 has achieved in the conventional example. 1
When considering light with a wavelength of μm, according to the calculation, the maximum reflectance of 0.49 can be achieved by the reflection at the Si / SiO 2 / Si interface as in the conventional example, whereas the reflection by the Si / Ag interface is achieved in this example. Therefore, a nearly perfect reflectance of 0.95 can be achieved, and more effective light absorption in the active layer 11 can be achieved.
以上の工程により、第１図（ｊ）に示す太陽電池９が
構成される。Through the above steps, the solar cell 9 shown in FIG. 1 (j) is constructed.
なお、この発明による太陽電池の製造方法を用いれ
ば、以下に示すように上記実施例とは表裏を逆転させた
構造の太陽電池を形成することも可能である。By using the method for manufacturing a solar cell according to the present invention, it is also possible to form a solar cell having a structure in which the front and back sides of the above embodiment are reversed as shown below.
すなわち、第２図（ａ）〜（ｊ）はこの発明による太
陽電池の製造方法の他の実施例を工程順に示す断面図で
ある。この図において、１〜17は第１図において同一符
号で示す部分と同一または相当する部分である。また、
工程も第１図に示す実施例と同一である部分が多いの
で、以下、第１図と異なっている部分のみについて説明
する。That is, FIGS. 2A to 2J are cross-sectional views showing another embodiment of the method for manufacturing a solar cell according to the present invention in the order of steps. In this figure, 1 to 17 are the same as or correspond to the parts indicated by the same reference numerals in FIG. Also,
Since many steps are the same as those in the embodiment shown in FIG. 1, only parts different from those in FIG. 1 will be described below.
拡散防止膜２上には、p-型アモルファスSi薄膜14を１
μｍ形成し（第２図（ｂ））、これを溶融・再結晶化し
て成長核層16として用い（第２図（ｃ））、さらに、こ
の上にp-型アモルファスSi薄膜４を30μｍ形成する（第
２図（ｅ））。A p - type amorphous Si thin film 14 is formed on the diffusion prevention film 2.
μm (FIG. 2 (b)), melted and recrystallized and used as the growth nucleus layer 16 (FIG. 2 (c)), and a p − -type amorphous Si thin film 4 is further formed thereon to 30 μm. (Fig. 2 (e)).
p-型アモルファスSi薄膜４上にp+型微結晶Si薄膜（こ
れは機能的には第１図の成長核層16に相当する）18,裏
面金属電極８を順次形成する（第２図（ｆ））。A p + -type microcrystalline Si thin film (which functionally corresponds to the growth nucleus layer 16 in FIG. 1) 18 and a back surface metal electrode 8 are sequentially formed on the p − -type amorphous Si thin film 4 (see FIG. 2 ( f)).
この上に、充填剤17を介して第２の支持基板13を貼り
付ける。On this, the second supporting substrate 13 is attached via the filler 17.
第１図に示す実施例では入射光に対して表面側の太陽
電池セルプロセスを完了させて第２の支持基板13を貼り
付けているのに対し、この実施例では裏面側を完了さ
せ、裏面側から第２の支持基板13を貼り付けている（第
２図（ｇ））。In the embodiment shown in FIG. 1, the solar cell process on the front surface side is completed with respect to incident light and the second support substrate 13 is attached, whereas in this embodiment, the back surface side is completed and the back surface side is completed. The second support substrate 13 is attached from the side (FIG. 2 (g)).
第１の支持基板1,拡散防止膜２を除去し、（第２図
（ｈ），（ｉ））露出させた成長核層16の上にn+型微結
晶Si薄膜5,反射防止膜兼透明導電膜6,表面金属電極７を
順次形成する（第２図（ｉ））。The first support substrate 1 and the diffusion prevention film 2 are removed, and the n + -type microcrystalline Si thin film 5 and the antireflection film are formed on the exposed growth nucleus layer 16 (FIGS. 2 (h) and (i)). The transparent conductive film 6 and the surface metal electrode 7 are sequentially formed (FIG. 2 (i)).
以上の工程により、太陽電池９が構成される。 The solar cell 9 is configured by the above steps.
なお、上記２つの実施例では拡散防止膜２はすべて除
去しているが、拡散防止膜２の除去は選択的であっても
よい。この場合、界面がSi/SiO2/Agの部分では１μｍの
波長の光で最大0.99とさらに多きな反射率を実現でき、
活性層11への有効な光吸収を図ることができる。Although the diffusion prevention film 2 is completely removed in the above two embodiments, the diffusion prevention film 2 may be removed selectively. In this case, in the part where the interface is Si / SiO 2 / Ag, a maximum reflectance of 0.99 can be realized with light having a wavelength of 1 μm,
It is possible to effectively absorb light into the active layer 11.
また、上記実施例では金属級Siからなる支持基板を用
いているが、支持基板の材料としては、ステンレスなど
金属のほか、BN（チッ化ホウ素）やセラミックなどを用
いてもよい。また、上記実施例では、いわゆるn+/p-/p+
型のSi太陽電池の例を示したが、p+/n-/n+型,n/p型,p/n
型など、別の導電型構成の、あるいはGaAs,InP,CuInSe2
など、他の結晶半導体材料を用いた太陽電池であっても
よい。さらに、上記の結晶半導体材料を２種以上組合
せ、あるいは上記の結晶半導体材料にアモルファス半導
体材料などを組み合わせて、積層型太陽電池を構成して
もよい。Further, although the supporting substrate made of metallurgical grade Si is used in the above-mentioned embodiment, the material of the supporting substrate may be metal such as stainless steel, BN (boron nitride) or ceramic. In the above embodiment, a so-called n + / p - / p +
Although an example of a Si solar cell type, p + / n - / n + -type, n / p-type, p / n
Type, another conductivity type configuration, or GaAs, InP, CuInSe 2
For example, a solar cell using another crystalline semiconductor material may be used. Furthermore, a laminated solar cell may be configured by combining two or more kinds of the above crystalline semiconductor materials, or combining the above crystalline semiconductor materials with an amorphous semiconductor material or the like.
第３図は、第１図（ｊ）に示した構造を利用して積層
型にした、この発明のさらに他の実施例を示す太陽電池
の構造断面図である。FIG. 3 is a structural cross-sectional view of a solar cell showing still another embodiment of the present invention, which is a laminated type utilizing the structure shown in FIG. 1 (j).
第３図において、１〜17は第１図（ｊ）において同一
符号で示す部分と同一または相当する部分である。19,2
0,21は前記n+型微結晶Si薄膜５上に、例えばプラズマCV
D法により順次形成したｐ型19,i型20,n型21アモルファ
スSi薄膜である。反射防止膜兼透明導電膜６はｎ型アモ
ルファスSi薄膜21上に形成する。この構造により、短波
長光はアモルファスSiセル（19,20,21）が（アモルファ
スSiの光学的禁制帯幅:1.7eV〜1.9eV）流波長光は多結
晶Siセル（14,4,5）が（結晶Siの禁制帯幅:1.1eV）それ
ぞれ分担して発電をおこない、より一層の高効率化を実
現できる。In FIG. 3, 1 to 17 are the same or corresponding parts as those shown by the same reference numerals in FIG. 1 (j). 19,2
0 and 21 are, for example, plasma CV on the n + type microcrystalline Si thin film 5.
It is a p-type 19, i-type 20, n-type 21 amorphous Si thin film sequentially formed by the D method. The antireflection film / transparent conductive film 6 is formed on the n-type amorphous Si thin film 21. With this structure, short-wavelength light is transmitted to amorphous Si cells (19,20,21) (optical band gap of amorphous Si: 1.7 eV to 1.9 eV), and flow-wavelength light is polycrystalline Si cells (14,4,5). (Forbidden band width of crystalline Si: 1.1 eV) is shared by each to generate electricity, and higher efficiency can be realized.
以上説明したように、この発明は、第１の支持基板上
に拡散防止膜としてのSiO2膜とアモルファスSi薄膜とを
順次形成し、該アモルファスSi薄膜上にキャップ層を形
成する工程と、次いで、前記アモルファスSi薄膜を溶融
・再結晶化して第１の多結晶Si薄膜を形成する工程と、
次いで前記キャップ層を除去して前記第１の多結晶Si薄
膜を露出させる工程と、次いで前記露出された第１の多
結晶Si薄膜の上に該第１の多結晶Si薄膜を核として第２
の多結晶Si薄膜を成長させる工程と、次いで前記第２の
多結晶Si薄膜の上に該第２の多結晶Si薄膜とは逆導電型
の結晶Si薄膜を形成する工程と、次いで前記結晶Si薄膜
上に表面金属電極を形成する工程と、次いで前記表面金
属電極上に第２の支持基板を貼り付けて、第１の支持基
板上に形成された各層を第２の支持基板により保持した
状態で、前記第１の支持基板を研削または溶解により除
去する工程と、次いで前記SiO2膜の少なくとも一部を溶
解により除去し、前記溶融・再結晶化した第１の多結晶
Si薄膜の少なくとも一部を露出させる工程と、次いで前
工程で露出された第１の多結晶Si薄膜に裏面金属電極を
形成する工程とを含むので、第１の支持基板が活性層に
有害な不純物を多く含む場合でも、拡散防止膜には開口
部を設けずに活性層を形成できるため、基板から活性層
への不純物拡散を小さく抑えられる。また、太陽電池の
機械的強度の保持および裏面金属電極の一部から、製造
工程の途中までの太陽電池の機械的強度の保持へと、基
板の役割は大幅に軽減される。さらに、裏面金属電極に
高反射のものを用いて、裏面からの光反射を十分におこ
なわせるようにしたので、活性層への光吸収をより有効
におこなうことができる。As described above, according to the present invention, a step of sequentially forming a SiO 2 film as a diffusion prevention film and an amorphous Si thin film on a first supporting substrate, and forming a cap layer on the amorphous Si thin film, A step of melting and recrystallizing the amorphous Si thin film to form a first polycrystalline Si thin film,
Next, a step of removing the cap layer to expose the first polycrystalline Si thin film, and a second step using the first polycrystalline Si thin film as a nucleus on the exposed first polycrystalline Si thin film
Growing a polycrystalline Si thin film, and then forming a crystalline Si thin film having a conductivity type opposite to that of the second polycrystalline Si thin film on the second polycrystalline Si thin film; A step of forming a surface metal electrode on the thin film, and then a state in which a second supporting substrate is attached on the surface metal electrode and each layer formed on the first supporting substrate is held by the second supporting substrate. Then, the step of removing the first supporting substrate by grinding or melting, and then removing at least a part of the SiO 2 film by melting, and melting and recrystallizing the first polycrystalline
Since the step of exposing at least a part of the Si thin film and the step of forming the back surface metal electrode on the first polycrystalline Si thin film exposed in the previous step are included, the first supporting substrate is harmful to the active layer. Even when a large amount of impurities are contained, the active layer can be formed without providing an opening in the diffusion prevention film, so that the diffusion of impurities from the substrate to the active layer can be suppressed small. Further, the role of the substrate is greatly reduced from the maintenance of the mechanical strength of the solar cell and the maintenance of the mechanical strength of the solar cell from a part of the back surface metal electrode to the middle of the manufacturing process. Further, since the back surface metal electrode having a high reflection is used so that the light is sufficiently reflected from the back surface, the light absorption in the active layer can be more effectively performed.
これにより、低純度の安価な支持基板を用いて、支持
基板から不純物拡散が少ない高品質の活性層を、拡散防
止膜上に容易に形成できるので、光エネルギーを有効に
電気エネルギーに変換できる高品質の太陽電池を低コス
トで得ることができる効果がある。Accordingly, a low-purity inexpensive support substrate can be used to easily form a high-quality active layer with less impurity diffusion from the support substrate on the diffusion prevention film, so that light energy can be effectively converted into electrical energy. There is an effect that a quality solar cell can be obtained at low cost.
第１図はこの発明による太陽電池の製造方法の一実施例
を工程順に示す断面図、第２図はこの発明による太陽電
池の製造方法の他の実施例を工程順に示す断面図、第３
図はこの発明による太陽電池の製造方法を用いた積層太
陽電池の構造を示す断面図、第４図は従来の太陽電池の
製造方法を示す断面図である。 図において、１は第１の支持基板、２は拡散防止膜、４
はp-型多結晶Si薄膜、５はn+型微結晶Si薄膜、６は反射
防止膜兼透明導電膜、７は表面金属電極、８は裏面金属
電極、９は太陽電池、11は活性層、12は表面電極、13は
第２の支持基板、14はp-型アモルファスSi膜、15はキャ
ップ層、16は成長核層、17は充填剤である。 なお、各図中の同一符号は同一または相当部分を示す。FIG. 1 is a sectional view showing an embodiment of a method for manufacturing a solar cell according to the present invention in the order of steps, and FIG. 2 is a sectional view showing another embodiment of a method for manufacturing a solar cell according to the present invention in the order of steps.
FIG. 4 is a sectional view showing a structure of a laminated solar cell using the method for manufacturing a solar cell according to the present invention, and FIG. 4 is a sectional view showing a method for manufacturing a conventional solar cell. In the figure, 1 is a first support substrate, 2 is a diffusion barrier film, 4
Is a p − type polycrystalline Si thin film, 5 is an n + type microcrystalline Si thin film, 6 is an antireflection film and a transparent conductive film, 7 is a front metal electrode, 8 is a back metal electrode, 9 is a solar cell, 11 is an active layer , 12 is a surface electrode, 13 is a second support substrate, 14 is a p - type amorphous Si film, 15 is a cap layer, 16 is a growth nucleus layer, and 17 is a filler. The same reference numerals in each drawing indicate the same or corresponding parts.
Claims (1)
O2膜とアモルファスSi薄膜とを順次形成し、該アモルフ
ァスSi薄膜上にキャップ層を形成する工程と、次いで、
前記アモルファスSi薄膜を溶融・再結晶化して第１の多
結晶Si薄膜を形成する工程と、次いで前記キャップ層を
除去して前記第１の多結晶Si薄膜を露出させる工程と、
次いで前記露出された第１の多結晶Si薄膜の上に該第１
の多結晶Si薄膜を核として第２の多結晶Si薄膜を成長さ
せる工程と、次いで前記第２の多結晶Si薄膜の上に該第
２の多結晶Si薄膜とは逆導電型の結晶Si薄膜を形成する
工程と、次いで前記結晶Si薄膜上に表面金属電極を形成
する工程と、次いで前記表面金属電極上に第２の支持基
板を貼り付けて、第１の支持基板上に形成された各層を
第２の支持基板により保持した状態で、前記第１の支持
基板を研削または溶解により除去する工程と、次いで前
記SiO2膜の少なくとも一部を溶解により除去し、前記溶
融・再結晶化した第１の多結晶Si薄膜の少なくとも一部
を露出させる工程と、次いで前工程で露出された第１の
多結晶Si薄膜に裏面金属電極を形成する工程とを含むこ
とを特徴とする太陽電池の製造方法。1. Si as a diffusion preventing film on a first supporting substrate
A step of sequentially forming an O 2 film and an amorphous Si thin film, and forming a cap layer on the amorphous Si thin film, and then,
Melting and recrystallizing the amorphous Si thin film to form a first polycrystalline Si thin film, and then removing the cap layer to expose the first polycrystalline Si thin film,
Then, the first polycrystalline Si thin film is exposed on the exposed first polycrystalline Si thin film.
Growing a second polycrystalline Si thin film by using the polycrystalline Si thin film as a nucleus, and then, a crystalline Si thin film having a conductivity type opposite to that of the second polycrystalline Si thin film on the second polycrystalline Si thin film. And then forming a surface metal electrode on the crystalline Si thin film, and then adhering a second support substrate on the surface metal electrode to form each layer formed on the first support substrate. While being held by the second supporting substrate, a step of removing the first supporting substrate by grinding or melting, and then at least a part of the SiO 2 film is removed by melting, and the molten and recrystallized A solar cell, comprising: a step of exposing at least a part of the first polycrystalline Si thin film; and a step of forming a back surface metal electrode on the first polycrystalline Si thin film exposed in the previous step. Production method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2206259A JP2536677B2 (en) | 1990-08-01 | 1990-08-01 | Solar cell manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2206259A JP2536677B2 (en) | 1990-08-01 | 1990-08-01 | Solar cell manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0491482A JPH0491482A (en) | 1992-03-24 |
| JP2536677B2 true JP2536677B2 (en) | 1996-09-18 |
Family
ID=16520372
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2206259A Expired - Fee Related JP2536677B2 (en) | 1990-08-01 | 1990-08-01 | Solar cell manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2536677B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0690014A (en) * | 1992-07-22 | 1994-03-29 | Mitsubishi Electric Corp | Thin solar cell and its production, etching method and automatic etching device, and production of semiconductor device |
| DE4325634C2 (en) * | 1993-07-30 | 2001-06-07 | Angew Solarenergie Ase Gmbh | Process for manufacturing an integrated thin solar cell |
| JP3672436B2 (en) | 1998-05-19 | 2005-07-20 | シャープ株式会社 | Method for manufacturing solar battery cell |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5117877A (en) * | 1974-08-02 | 1976-02-13 | Matsushita Electric Ind Co Ltd | |
| JPS5283187A (en) * | 1975-12-30 | 1977-07-11 | Seiko Epson Corp | Production of solar cell |
| JPS52117057A (en) * | 1976-03-29 | 1977-10-01 | Kiyoshi Takahashi | Method of making multiilayer thin film of semiconductor |
| JPS5491087A (en) * | 1977-12-28 | 1979-07-19 | Seiko Instr & Electronics Ltd | Manufacture of thin-film solar cell |
| JPS5613779A (en) * | 1979-07-16 | 1981-02-10 | Shunpei Yamazaki | Photoelectric converter and its preparation |
| JPS58173873A (en) * | 1982-04-05 | 1983-10-12 | Hitachi Ltd | Amorphous si solar battery and manufacture thereof |
| JPS6469057A (en) * | 1987-09-10 | 1989-03-15 | Fujitsu Ltd | Semiconductor device and manufacture thereof |
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1990
- 1990-08-01 JP JP2206259A patent/JP2536677B2/en not_active Expired - Fee Related
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