JP2815688B2 - Manufacturing method of thin film solar cell - Google Patents
Manufacturing method of thin film solar cellInfo
- Publication number
- JP2815688B2 JP2815688B2 JP2211312A JP21131290A JP2815688B2 JP 2815688 B2 JP2815688 B2 JP 2815688B2 JP 2211312 A JP2211312 A JP 2211312A JP 21131290 A JP21131290 A JP 21131290A JP 2815688 B2 JP2815688 B2 JP 2815688B2
- Authority
- JP
- Japan
- Prior art keywords
- solar cell
- photoelectric conversion
- layer
- conversion layer
- silicon oxide
- 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 - Lifetime
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
- Y02E10/548—Amorphous silicon PV cells
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、透光性基板を通って入射した光が非晶質シ
リコン（以下ａ−Siと略す）を主材料とした光電変換層
により起電力を発生させる薄膜太陽電池の製造方法に関
する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photoelectric conversion layer whose main material is amorphous silicon (hereinafter abbreviated as a-Si). The present invention relates to a method for manufacturing a thin-film solar cell that generates an electromotive force.
モノシランガスなどのグロー放電分解や光分解により
形成される非晶質シリコン薄膜は、気相成長法によって
得られるため大面積化が容易であり、低コスト太陽電池
の光電変換層に用いられる。このような太陽電池の効率
の向上のためには、光電変換層に入射する光の量の大き
いことが望ましい。このために光電変換層の光の入射側
と反対側に設けられる裏面電極を反射率の高い金属で形
成し、その電極面での反射を利用することが行われる。
しかし、裏面電極に用いる金属、例えば銀とシリコンと
の合金がａ−Si層と裏面電極の界面に形成されると、こ
の合金層が透明度が低いために反射特性が悪くなる。第
２図は特開昭55−108780号公報に記載されたａ−Si太陽
電池で、ガラス基板１の上に縁部に集電電極３を設けた
透明電極２を介して形成されたａ−Si光電変換層４と銀
電極５との間に透明導電層６を介在させ、ａ−Si層と銀
電極を十分離してやることで合金化を抑制するものであ
る。ａ−Si層４と銀電極５を合金化が起こらない程度に
隔てるが、銀電極によって反射した光をａ−Si層に入射
させ、なおかつ太陽電池の直列抵抗成分を大きくしない
ために、介在層６は必然的に透明かつ導電性を持ってい
る必要があった。An amorphous silicon thin film formed by glow discharge decomposition or photolysis of monosilane gas or the like can be easily formed into a large area because it is obtained by a vapor phase growth method, and is used for a photoelectric conversion layer of a low-cost solar cell. In order to improve the efficiency of such a solar cell, it is desirable that the amount of light incident on the photoelectric conversion layer be large. For this purpose, a back electrode provided on the side opposite to the light incident side of the photoelectric conversion layer is formed of a metal having a high reflectance, and the reflection on the electrode surface is used.
However, when a metal used for the back electrode, for example, an alloy of silver and silicon is formed at the interface between the a-Si layer and the back electrode, the reflection characteristics are deteriorated because the alloy layer has low transparency. FIG. 2 shows an a-Si solar cell described in Japanese Patent Application Laid-Open No. 55-108780, in which an a-Si solar cell is formed on a glass substrate 1 via a transparent electrode 2 provided with a collecting electrode 3 at the edge. The alloying is suppressed by interposing the transparent conductive layer 6 between the Si photoelectric conversion layer 4 and the silver electrode 5 and separating the a-Si layer and the silver electrode sufficiently. The a-Si layer 4 and the silver electrode 5 are separated to such an extent that alloying does not occur. However, in order to make the light reflected by the silver electrode incident on the a-Si layer and not to increase the series resistance component of the solar cell, an intervening layer is formed. No. 6 needed to be transparent and conductive.
ｓ−Si層の光入射側だけでなく、反対側にも透明導電
層６を形成することは、材料費の増加のほかに蒸着装置
あるいはスパッタリング装置等の高価な装置の増設を必
要とし、太陽電池の製造原価を高くするという問題があ
った。さらに、ａ−Si層４を熱で劣化させないために透
明導電層６を200℃以下の比較的低い温度で形成しなけ
ればならず、透明度の高い、高品質の膜を形成すること
が困難であった。Forming the transparent conductive layer 6 not only on the light incident side of the s-Si layer but also on the opposite side requires an increase in material costs and the addition of expensive equipment such as a vapor deposition apparatus or a sputtering apparatus. There was a problem that the manufacturing cost of the battery was increased. Further, in order to prevent the a-Si layer 4 from being deteriorated by heat, the transparent conductive layer 6 must be formed at a relatively low temperature of 200 ° C. or less, and it is difficult to form a high-quality film with high transparency. there were.
本発明の目的は、上述の問題に対処し、透明導電層を
介在させないで裏面電極の金属とａ−Siとの合金化を防
いだ薄膜太陽電池の製造方法を提供することにある。An object of the present invention is to provide a method of manufacturing a thin-film solar cell which addresses the above-mentioned problem and prevents alloying of a-Si and a metal of a back electrode without interposing a transparent conductive layer.
上記の目的を達成するために、本発明によれば、透光
絶縁性基板上に透明導電膜よりなる透明電極を介して非
晶質シリコンを主材料とした光電変換層を積層し、次い
で酸化性雰囲気中で100〜200℃の温度で熱処理してその
光電変換層の表面に10〜30Åの厚さの酸化シリコン層を
形成し、さらにその上に金属よりなる裏面電極を設ける
こととする。もしくは、透光絶縁性基板上に透明導電膜
よりなる透明電極を介して非晶質シリコンを主材料とし
た光電変換層を積層し、次いで酸化性雰囲気中で放電を
発生させてその光電変換層の表面に10〜30Åの厚さの酸
化シリコン層を形成し、さらにその上に金属よりなる裏
面電極を設けることとする。In order to achieve the above object, according to the present invention, a photoelectric conversion layer containing amorphous silicon as a main material is laminated on a transparent insulating substrate via a transparent electrode made of a transparent conductive film, and then oxidized. Heat treatment at a temperature of 100 to 200 ° C. in a neutral atmosphere to form a silicon oxide layer having a thickness of 10 to 30 ° on the surface of the photoelectric conversion layer, and further provide a back electrode made of metal thereon. Alternatively, a photoelectric conversion layer mainly composed of amorphous silicon is laminated on a transparent insulating substrate via a transparent electrode made of a transparent conductive film, and then the discharge is generated in an oxidizing atmosphere to form the photoelectric conversion layer. A silicon oxide layer having a thickness of 10 to 30 mm is formed on the surface of the substrate, and a back electrode made of metal is further provided thereon.
光電変換層と裏面電極の間にシリコン酸化膜が介在す
るので裏面電極の金属とａ−Siとの合金が生ずることな
く、反射特性が向上する。シリコン酸化膜は透光性であ
り、絶縁性ではあるが厚さが10〜30Åと極めて薄いので
直列抵抗成分を大きくすることはない。さらに100〜200
℃の低温での熱処理で、あるいは放電発生のみで形成で
きるため、ａ−Si層が熱で劣化することがない。Since the silicon oxide film is interposed between the photoelectric conversion layer and the back surface electrode, the alloy of the metal of the back surface electrode and a-Si does not occur, and the reflection characteristics are improved. The silicon oxide film is translucent and insulative, but has a very thin thickness of 10 to 30 °, so that the series resistance component does not increase. Further 100-200
Since the a-Si layer can be formed by heat treatment at a low temperature of ° C. or only by generation of electric discharge, the a-Si layer does not deteriorate by heat.
第１図は本発明の一実施例の薄膜太陽電池の製造方法
により製造された薄膜太陽電池の断面構造を示し、第２
図と共通の部分には同一の符号が付されている。この太
陽電池は次のようにして作製された。先ずガラス基板１
の上に透明導電膜を蒸着あるいはスパッタリング形成し
て透明電極２とし、その上にａ−Siあるいはａ−SiC薄
膜を用いてｐ−ｉ−ｎ接合を有する光電変換層４を形成
した。次いで、オーブンに入れて空気中での熱処理を行
った。熱処理時の基板温度は100〜200℃で、処理時間は
５〜100時間であった。その後、銀裏面電極５および透
明電極２の縁部上の集電電極３を形成した。このａ−Si
太陽電池の短絡電流密度は、空気中での熱処理時間によ
って第３図のように変化する。パラメータは基板温度で
ある。基板温度100〜200℃において熱処理時間の増加に
ともない短絡電流密度が増加している。短絡電流密度の
増加は最大で1.6mA/cm2である。窒素雰囲気中で同様な
熱処理を行った場合には短絡電流密度の増加は見られな
かった。以上のことから、空気中で熱処理した場合の短
絡電流密度の増加は、光電変換層４の表面に酸化シリコ
ン層７が形成されることによると考えられる。FIG. 1 shows a cross-sectional structure of a thin-film solar cell manufactured by a method for manufacturing a thin-film solar cell according to one embodiment of the present invention.
Parts common to the drawings are denoted by the same reference numerals. This solar cell was manufactured as follows. First, the glass substrate 1
A transparent conductive film was deposited or sputter-formed thereon to form a transparent electrode 2, and a photoelectric conversion layer 4 having a pin junction was formed thereon using an a-Si or a-SiC thin film. Next, it was placed in an oven and heat-treated in air. The substrate temperature during the heat treatment was 100 to 200 ° C., and the processing time was 5 to 100 hours. Then, the current collecting electrode 3 on the edge of the silver back electrode 5 and the transparent electrode 2 was formed. This a-Si
The short-circuit current density of the solar cell changes as shown in FIG. 3 depending on the heat treatment time in air. The parameter is the substrate temperature. At a substrate temperature of 100 to 200 ° C., the short-circuit current density increases as the heat treatment time increases. The increase in short circuit current density is at most 1.6 mA / cm 2 . When the same heat treatment was performed in a nitrogen atmosphere, no increase in short-circuit current density was observed. From the above, it is considered that the increase in the short-circuit current density when the heat treatment is performed in the air is due to the formation of the silicon oxide layer 7 on the surface of the photoelectric conversion layer 4.
第４図に150℃で100時間の熱処理を行い、酸化層７を
形成したａ−Si太陽電池および酸化層を形成しなかった
ａ−Si太陽電池の電流・電圧特性をそれぞれ線41,42で
示す。酸化シリコン層を形成しなかった場合の変換効率
が11.6％であったのに対し、酸化シリコン層７を形成す
ることによって12.4％に向上した。FIG. 4 shows the current / voltage characteristics of the a-Si solar cell having the oxide layer 7 formed thereon and the a-Si solar cell having no oxide layer formed thereon by heat treatment at 150 ° C. for 100 hours. Show. The conversion efficiency when the silicon oxide layer was not formed was 11.6%, whereas the conversion efficiency was improved to 12.4% by forming the silicon oxide layer 7.
本発明に基づいて形成される酸化シリコン層７は絶縁
物である。従って、膜厚は太陽電池の直列抵抗を増加さ
せない範囲、すなわち、トンネリングによって電流が流
れる10〜30Å程度に制限される。この膜厚は、第２図に
示すようにａ−SiとAgの合金化を防ぐために従来設けら
れていた透明導電層６にくらべて格段に薄いものであ
る。以上のように本発明で用いた酸化シリコン層は導電
率および膜厚が従来の透明導電層と全く異なるものであ
る。The silicon oxide layer 7 formed according to the present invention is an insulator. Therefore, the film thickness is limited to a range that does not increase the series resistance of the solar cell, that is, about 10 to 30 ° at which current flows by tunneling. As shown in FIG. 2, this film thickness is much thinner than the transparent conductive layer 6 conventionally provided to prevent alloying of a-Si and Ag. As described above, the silicon oxide layer used in the present invention is completely different in conductivity and film thickness from the conventional transparent conductive layer.
次に、酸化シリコン層７を形成するための他の実施例
について述べる。第１図のａ−Si層４まで形成した基板
を、容量結合形の真空反応室の一方の電極に装着する。
真空引きの後、酸素ガスを導入し、0.2〜1torrの圧力に
保つ。その後、電極間に電圧を印加することによって放
電を発生させ、酸化膜を10〜30Åの厚さに形成する。第
５図に、この方法で酸化膜を形成した場合およびしなか
った場合のａ−Si太陽電池の電流・電圧特性をそれぞれ
線51,52で示す。酸化膜を形成することにより短絡電流
が1.6mA/cm2向上した。これにより、変換効率も11.6％
から12.1％に向上した。Next, another embodiment for forming the silicon oxide layer 7 will be described. The substrate formed up to the a-Si layer 4 in FIG. 1 is mounted on one electrode of a capacitively coupled vacuum reaction chamber.
After evacuation, oxygen gas is introduced and the pressure is maintained at 0.2-1 torr. Thereafter, a discharge is generated by applying a voltage between the electrodes to form an oxide film with a thickness of 10 to 30 mm. FIG. 5 shows current / voltage characteristics of the a-Si solar cell with and without the oxide film formed by this method by lines 51 and 52, respectively. The formation of the oxide film improved the short-circuit current by 1.6 mA / cm 2 . As a result, the conversion efficiency is 11.6%
From 12.1%.
本発明によれば、ａ−Siを主材料とする光電変換層を
形成後その表面を変化するだけで、SnO2,ITO等の特殊な
材料を用いることなく裏面電極の反射率を向上させるこ
と、すなわち、薄膜太陽電池の電流を増加させることが
できる。また、本発明によれば、蒸着装置あるいはスパ
ッタリング装置等の高価な装置を用いることなく薄膜太
陽電池の光電変換層への入射光量を増加させ、特性を向
上することができる。According to the present invention, it is possible to improve the reflectance of the back electrode without using a special material such as SnO 2 or ITO by merely changing the surface after forming a photoelectric conversion layer containing a-Si as a main material. That is, the current of the thin-film solar cell can be increased. Further, according to the present invention, the amount of light incident on the photoelectric conversion layer of the thin-film solar cell can be increased without using an expensive device such as a vapor deposition device or a sputtering device, and the characteristics can be improved.
以上のような理由から、本発明によれば従来法による
よりも低原価で、効率の高い薄膜太陽電池を製造するこ
とができる。For the above reasons, according to the present invention, a thin-film solar cell with high efficiency can be manufactured at lower cost than the conventional method.
第１図は本発明の一実施例の薄膜太陽電池の製造方法に
より製造されたａ−Si太陽電池の断面図、第２図は公知
のａ−Si太陽電池の断面図、第３図は本発明による製造
工程中の基板の熱処理時間と短絡電流密度との基板温度
をパラメータとしての関係線図、第４図は本発明の一実
施例により酸化シリコン層を形成した場合および形成し
なかった場合のａ−Si太陽電池の電流・電圧特性図、第
５図は本発明の他の実施例により酸化シリコン層を形成
した場合およびしなかった場合のａ−Si太陽電池の電流
・電圧特性図である。 1:ガラス基板、2:透明電極、4:光電変換層、5:裏面電
極、7:酸化シリコン層。FIG. 1 is a cross-sectional view of an a-Si solar cell manufactured by a method of manufacturing a thin-film solar cell according to one embodiment of the present invention, FIG. 2 is a cross-sectional view of a known a-Si solar cell, and FIG. FIG. 4 is a graph showing the relationship between the substrate heat treatment time and the short-circuit current density during the manufacturing process according to the present invention, using the substrate temperature as a parameter. 5 is a current-voltage characteristic diagram of an a-Si solar cell, and FIG. 5 is a current-voltage characteristic diagram of an a-Si solar cell with and without a silicon oxide layer according to another embodiment of the present invention. is there. 1: glass substrate, 2: transparent electrode, 4: photoelectric conversion layer, 5: back electrode, 7: silicon oxide layer.
Claims (2)
明電極を介して非晶質シリコンを主材料とした光電変換
層を積層し、次いで酸化性雰囲気中で100〜200℃の温度
で熱処理してその光電変換層の表面に10〜30Åの厚さの
酸化シリコン層を形成し、さらにその上に金属よりなる
裏面電極を設けることを特徴とする薄膜太陽電池の製造
方法。1. A photoelectric conversion layer mainly composed of amorphous silicon is laminated on a transparent insulating substrate via a transparent electrode made of a transparent conductive film, and then a temperature of 100 to 200 ° C. in an oxidizing atmosphere. Forming a silicon oxide layer having a thickness of 10 to 30 mm on the surface of the photoelectric conversion layer, and further providing a back electrode made of a metal on the silicon oxide layer.
明電極を介して非晶質シリコンを主材料とした光電変換
層を積層し、次いで酸化性雰囲気中で放電を発生させて
その光電変換層の表面に10〜30Åの厚さの酸化シリコン
層を形成し、さらにその上に金属よりなる裏面電極を設
けることを特徴とする薄膜太陽電池の製造方法。2. A photoelectric conversion layer mainly composed of amorphous silicon is laminated on a transparent insulating substrate via a transparent electrode made of a transparent conductive film, and then a discharge is generated in an oxidizing atmosphere. A method for manufacturing a thin-film solar cell, comprising: forming a silicon oxide layer having a thickness of 10 to 30 mm on a surface of a photoelectric conversion layer, and further providing a back electrode made of metal thereon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2211312A JP2815688B2 (en) | 1990-08-09 | 1990-08-09 | Manufacturing method of thin film solar cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2211312A JP2815688B2 (en) | 1990-08-09 | 1990-08-09 | Manufacturing method of thin film solar cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0494171A JPH0494171A (en) | 1992-03-26 |
| JP2815688B2 true JP2815688B2 (en) | 1998-10-27 |
Family
ID=16603857
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2211312A Expired - Lifetime JP2815688B2 (en) | 1990-08-09 | 1990-08-09 | Manufacturing method of thin film solar cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2815688B2 (en) |
-
1990
- 1990-08-09 JP JP2211312A patent/JP2815688B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0494171A (en) | 1992-03-26 |
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