JP2002033494A - Photovoltaic device and its manufacturing method - Google Patents
Photovoltaic device and its manufacturing methodInfo
- Publication number
- JP2002033494A JP2002033494A JP2000215044A JP2000215044A JP2002033494A JP 2002033494 A JP2002033494 A JP 2002033494A JP 2000215044 A JP2000215044 A JP 2000215044A JP 2000215044 A JP2000215044 A JP 2000215044A JP 2002033494 A JP2002033494 A JP 2002033494A
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- Prior art keywords
- film
- thickness
- amorphous silicon
- layer
- photovoltaic device
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Classifications
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- 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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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、非晶質シリコン光
起電力装置およびその製造方法に関するものである。[0001] 1. Field of the Invention [0002] The present invention relates to an amorphous silicon photovoltaic device and a method of manufacturing the same.
【０００２】[0002]
【従来の技術】太陽の光から直接電気を得ることができ
る光起電力装置（太陽電池）は、半永久的で無公害の新
たなエネルギー源として実用化されつつある。最近では
太陽光をいかにして効率よく電気エネルギーに変換する
か、また、いかにして発電コストを下げるかを中心に研
究開発が進められている。その中で非晶質シリコン（ア
モルファスシリコン：ａ−Ｓｉ）太陽電池が大量普及型
の太陽電池として注目されている。非晶質シリコン太陽
電池は結晶シリコン太陽電池に比べ、発電効率の点では
多少劣るものの、プラズマＣＶＤ（ Chemical Vapor De
position：化学気相析出）法により製造するため大量生
産に適しており、２００℃程度の比較的低温プロセスで
製造できるので製造エネルギー消費量が少ないこと、基
板の種類に限定されないこと等の利点を有していて将来
の普及型太陽電池として最も期待されている。2. Description of the Related Art A photovoltaic device (solar cell) capable of directly obtaining electricity from sunlight is being put to practical use as a semi-permanent and non-polluting new energy source. Recently, research and development have been focused on how to efficiently convert sunlight into electric energy and how to reduce power generation costs. Among them, an amorphous silicon (amorphous silicon: a-Si) solar cell has been attracting attention as a mass-dispersed solar cell. Amorphous silicon solar cells are somewhat inferior in power generation efficiency to crystalline silicon solar cells, but plasma CVD (Chemical Vapor Deposition).
position: It is suitable for mass production because it is manufactured by the chemical vapor deposition) method. It can be manufactured by a relatively low-temperature process of about 200 ° C, so it has advantages such as low manufacturing energy consumption and not being limited to the type of substrate. It is expected to be the most popular solar cell in the future.
【０００３】図１に非晶質シリコン太陽電池の基本構造
を示す。 図１に示すとおり非晶質シリコン太陽電池
は、ガラス基板１上に真性非晶質シリコン膜（以下、ｉ
層と呼ぶ）４をｐ層非晶質シリコン（以下、ｐ層と呼
ぶ）膜３とｎ層非晶質シリコン（以下、ｎ層と呼ぶ）膜
５で挟んだｐｉｎ構造の半導体膜６を設け、この半導体
膜に電流を取り出すための透明電極２と金属電極７とを
設けた構造をとっている。このような積層構造体に太陽
光が入射すると、光電効果により電子−正孔対が発生
し、電子−正孔はｐｉｎ接合でｉ層内部に形成された電
界によって、電子はｎ層側へ、正孔はｐ層側へ移動す
る。この時透明電極膜２と金属電極膜７間に外部負荷Ｒ
を接続すると外部回路に電流が流れて発電が行われる仕
組みになっている。これらの半導体膜６は通常熱ＣＶＤ
法やプラズマＣＶＤ法によって形成されている。FIG. 1 shows a basic structure of an amorphous silicon solar cell. As shown in FIG. 1, the amorphous silicon solar cell has an intrinsic amorphous silicon film (hereinafter referred to as i) on a glass substrate 1.
A semiconductor film 6 having a pin structure in which a p-type amorphous silicon (hereinafter, referred to as a p-layer) film 3 and an n-layer amorphous silicon (hereinafter, referred to as an n-layer) film 5 are provided. The semiconductor film has a structure in which a transparent electrode 2 for extracting a current and a metal electrode 7 are provided. When sunlight is incident on such a laminated structure, electron-hole pairs are generated by the photoelectric effect, and electrons are moved to the n-layer side by an electric field formed inside the i-layer by a pin junction. The holes move to the p-layer side. At this time, an external load R is applied between the transparent electrode film 2 and the metal electrode film 7.
Is connected, a current flows through the external circuit to generate power. These semiconductor films 6 are usually formed by thermal CVD.
It is formed by a method or a plasma CVD method.
【０００４】上述の通り非晶質シリコン太陽電池におい
ては、光を吸収して発電するのはｉ層であるからｉ層の
膜質が発電効率を左右するので、いかにして高品質のｉ
層をつくるかが重要な課題となっている。十分な変換効
率を達成するためにはｉ層の膜厚は通常数百ｎｍであり
ｐ層、ｎ層の膜厚（通常数十ｎｍ）の数十倍必要であ
る。従って、生産性を上げてコストを下げるためには、
ｉ層の膜厚をできる限り薄くしてしかも成膜速度をでき
る限り高めることが重要となる。しかし、成膜速度を上
げていくと良質な半導体膜が得られ難くなる難点があ
る。近年、ｉ層の膜厚の膜厚は次第に薄くなってきてお
り、十分な光を吸収して電子−正孔対を発生させるため
のｉ層の膜厚は、通常３００〜６００ｎｍ程度とされて
いる（特開平１１−１３５８１４参照）。As described above, in an amorphous silicon solar cell, it is the i-layer that absorbs light to generate power, and the film quality of the i-layer determines the power generation efficiency.
Making layers is an important issue. In order to achieve sufficient conversion efficiency, the thickness of the i-layer is usually several hundred nm, and several tens of times the thickness of the p-layer and the n-layer (typically tens of nm). Therefore, to increase productivity and lower costs,
It is important to reduce the thickness of the i-layer as much as possible and to increase the deposition rate as much as possible. However, there is a problem that it becomes difficult to obtain a high-quality semiconductor film as the film formation speed is increased. In recent years, the thickness of the i-layer has been gradually reduced, and the thickness of the i-layer for absorbing sufficient light to generate electron-hole pairs is usually about 300 to 600 nm. (See JP-A-11-135814).
【０００５】ｉ層に入射した太陽光により発生した電子
−正孔対が全て発電に寄与するわけではなく、発生した
キャリアの一部は再結合して消滅する。特に、ｉ層成膜
中に形成されるダングリングボンドはキャリアのトラッ
プとなり、出力電流の低下を招く。従ってこのような欠
陥を極力低くしたｉ層を形成しなければならない。ｉ層
の欠陥を低減させるためには、ｉ層を形成する際に微量
の水素を添加する方法（特開平１１−２１４７１７参
照）や、ｐ層とｉ層との間にバッファ層を設け、ｐ層か
らの不純物の拡散を防止する方法（特開２０００−１６
４９０４参照）が知られている。[0005] Not all electron-hole pairs generated by sunlight incident on the i-layer contribute to power generation, and some of the generated carriers recombine and disappear. In particular, dangling bonds formed during the formation of the i-layer serve as traps for carriers, which causes a decrease in output current. Therefore, an i-layer in which such defects are minimized must be formed. In order to reduce defects in the i-layer, a method of adding a small amount of hydrogen when forming the i-layer (see JP-A-11-214717), or providing a buffer layer between the p-layer and the i-layer, Method for preventing diffusion of impurities from layer (Japanese Patent Laid-Open No. 2000-16)
4904) are known.
【０００６】また、図１に示すように、一般に太陽電池
は２つの電極で非晶質シリコン半導体膜を挟んだ構造を
しており、２つの電極のうち光が入射する側には透明電
極を、また他方には金属の裏面電極を用いる。この裏面
電極としては低抵抗のＡｌやＡｇが用いられる。一方、
透明電極にはＳｎＯ2 （酸化錫）やＩＴＯ（インジウム
・錫酸化物）またはＺｎＯ（酸化亜鉛）等の透明導電膜
が用いられるが、これらの透明導電膜は電気抵抗率が約
５×１０-4Ω・ｃｍとＡｌやＡｇ等の金属膜より２桁程
大きいため、発生した電流が透明電極を流れる間に電力
損失が生じる。それは基板面積が大きくなる程顕著とな
り、外部へ取り出せる電力を減少させる。電力損失を小
さくするための構造として、図２に示すような集積型太
陽電池がある。これは前記構造の積層膜からなる太陽電
池の単位セルを、１枚の基板上に複数個作成してそれぞ
れの単位セルを基板上で電気的に直列接続したものであ
る。As shown in FIG. 1, a solar cell generally has a structure in which an amorphous silicon semiconductor film is sandwiched between two electrodes, and a transparent electrode is provided on a side of the two electrodes where light is incident. On the other hand, a metal back electrode is used. As this back electrode, low-resistance Al or Ag is used. on the other hand,
For the transparent electrode, a transparent conductive film such as SnO 2 (tin oxide), ITO (indium tin oxide), or ZnO (zinc oxide) is used. These transparent conductive films have an electric resistivity of about 5 × 10 −. Since the resistance is 4 Ω · cm, which is about two orders of magnitude larger than that of a metal film such as Al or Ag, a power loss occurs while the generated current flows through the transparent electrode. This becomes more remarkable as the substrate area increases, and reduces the power that can be taken out. As a structure for reducing power loss, there is an integrated solar cell as shown in FIG. This is one in which a plurality of unit cells of a solar cell made of a laminated film having the above-described structure are formed on one substrate, and the respective unit cells are electrically connected in series on the substrate.
【０００７】図２は集積型太陽電池の断面構造を示し、
１１には透明絶縁性のガラス基板、１２には透明導電膜
からなる透明電極膜、１６には非晶質シリコンからなる
半導体膜、１７にはＡｌやＡｇ等の金属からなる裏面電
極膜が用いられ、図面左側の単位セル１０の裏面電極膜
１７の一部及び画面中央の単位セル１０の透明電極膜１
２の一部がそれぞれ延在し、互いにコンタクト部１５の
位置で重畳接続されている。開口部２０は直列接続方向
に垂直（紙面に垂直方向）にレーザスクライブによって
形成された単位セル毎に分離するための開口部である。FIG. 2 shows a sectional structure of the integrated solar cell,
11 is a transparent insulating glass substrate, 12 is a transparent electrode film made of a transparent conductive film, 16 is a semiconductor film made of amorphous silicon, and 17 is a back electrode film made of a metal such as Al or Ag. A part of the back electrode film 17 of the unit cell 10 on the left side of the drawing and the transparent electrode film 1 of the unit cell 10 at the center of the screen.
Part of the two extend and are connected to each other at the position of the contact portion 15. The opening 20 is an opening for separating each unit cell formed by laser scribing in the direction perpendicular to the series connection direction (the direction perpendicular to the paper surface).
【０００８】従来、金属膜からなる裏面電極膜１７の開
口部２０の形成方法は特公平５−２８９１１に示される
ように裏面電極膜の金属膜面にレーザ光を照射してスク
ライブする方法と、特開昭６１−６８２８に示されるよ
うに透明絶縁性のガラス基板１１側からレーザ光を照射
する方法が知られている。前者の開示例の場合には、非
晶質シリコンからなる半導体膜１６の膜厚は５００ｎ
ｍ、裏面電極膜１７の膜厚は２００ｎｍ以上、代表的に
は５００ｎｍの金属膜が使用されている。また後者の開
示例ででは、非晶質シリコンからなる半導体膜１６の膜
厚は４１０〜６７０ｎｍ、裏面電極膜１７の膜厚は２０
０ｎｍ〜１μの金属膜が使用されている。Conventionally, a method of forming the opening 20 of the back electrode film 17 made of a metal film includes a method of scribing by irradiating a laser beam to the metal film surface of the back electrode film as shown in Japanese Patent Publication No. 5-28911. As shown in JP-A-61-6828, a method of irradiating a laser beam from the transparent insulating glass substrate 11 side is known. In the case of the former disclosed example, the thickness of the semiconductor film 16 made of amorphous silicon is 500 n.
m, a metal film having a thickness of 200 nm or more, typically 500 nm, of the back electrode film 17 is used. In the latter disclosed example, the thickness of the semiconductor film 16 made of amorphous silicon is 410 to 670 nm, and the thickness of the back electrode film 17 is 20 nm.
A metal film of 0 nm to 1 μm is used.
【０００９】裏面電極膜１７と半導体膜１６をスクライ
ブして開口部２０を形成する場合において、前者のよう
な金属膜面にレーザビームを照射する方法では、金属膜
表面が高い反射率を有するために大きいレーザパワーが
必要であった。これに対して後者のレーザビームをガラ
スのような透明絶縁基板側から照射する方法は、少ない
レーザパワーで加工できるため、光起電力装置の製造方
法としては、後者のような透明絶縁基板側からのレーザ
ビーム照射法が一般的に行われている。この基板側から
のレーザビーム照射法の場合、透明絶縁基板及び透明電
極膜を透過した光が半導体膜で吸収されて熱に変わると
きに、半導体膜内の多量の結合水素の分解ガスの膨張に
より、金属電極膜がちぎられて吹き飛ばされるメカニズ
ムによってスクライブが進行する。従って、適度な膜厚
の半導体膜が必要となり、半導体膜の膜厚はすくなくと
も４００ｎｍ程度必要とされている。In the case where the opening 20 is formed by scribing the back electrode film 17 and the semiconductor film 16, the former method of irradiating the metal film surface with a laser beam has a high reflectance because the metal film surface has a high reflectance. Required a large laser power. In contrast, the latter method of irradiating a laser beam from a transparent insulating substrate side such as glass can be processed with a small laser power. Is generally performed. In the case of the laser beam irradiation method from the substrate side, when light transmitted through the transparent insulating substrate and the transparent electrode film is absorbed by the semiconductor film and converted into heat, a large amount of decomposition gas of bonded hydrogen in the semiconductor film expands due to expansion. Then, the scribe proceeds by a mechanism in which the metal electrode film is torn off and blown off. Therefore, a semiconductor film having an appropriate thickness is required, and the thickness of the semiconductor film is required to be at least about 400 nm.
【００１０】[0010]
【発明が解決しようとする課題】前述の通り、非晶質シ
リコン光起電力変換素子の発電効率は、非晶質シリコン
半導体膜、特に、ｉ層からなる非晶質シリコン半導体膜
の品質に大きく依存しており、高品質のｉ層を能率良く
製造することが発電コストを引き下げる点からも至上命
題となっている。変換効率を向上させるためには、入射
した光によって電子−正孔対が発生するためのある程度
の厚さのｉ層が必要である。また、高品質のｉ層を得る
にはｉ層の成膜速度をある程度低く抑え、穏やかに成長
させる必要があり、ｉ層非晶質シリコンの膜厚が厚いと
それだけ生産効率が低くなることにつながる。As described above, the power generation efficiency of the amorphous silicon photovoltaic conversion device is greatly affected by the quality of the amorphous silicon semiconductor film, particularly, the quality of the amorphous silicon semiconductor film composed of the i-layer. Therefore, efficient production of a high-quality i-layer is the most important proposition from the viewpoint of reducing power generation costs. In order to improve the conversion efficiency, an i-layer having a certain thickness for generating electron-hole pairs by incident light is required. Further, in order to obtain a high-quality i-layer, it is necessary to suppress the film formation rate of the i-layer to some extent and to grow it gently. As the thickness of the i-layer amorphous silicon increases, the production efficiency decreases. Connect.
【００１１】また、ｉ層の厚さが必要以上に厚くなると
時間経過とともに生ずる光劣化による光起電力変換特性
の低下が著しくなる。さらに、レーザビームを透明絶縁
基板裏面側から照射して金属電極膜をスクライブ加工す
る際、金属電極膜の膜厚が適正でないと、金属電極のバ
リが発生して、透明電極膜に接触することにより、透明
電極膜と金属電極膜間の絶縁抵抗が低下して外部出力電
力の低下を招く。When the thickness of the i-layer becomes unnecessarily large, the photovoltaic conversion characteristics are significantly reduced due to photodegradation occurring with the passage of time. Furthermore, when the metal electrode film is scribed by irradiating a laser beam from the back side of the transparent insulating substrate, if the thickness of the metal electrode film is not appropriate, burrs of the metal electrode may occur and the metal electrode film may come into contact with the transparent electrode film. As a result, the insulation resistance between the transparent electrode film and the metal electrode film is reduced, and the external output power is reduced.
【００１２】このような条件下で、生産効率を上げるべ
く、非晶質シリコン半導体膜の厚さを薄くして、なおか
つ高い光電変換効率を維持するには、欠陥の少ない高品
質のｉ層非晶質シリコンが要求されるが、ｉ層非晶質シ
リコンの欠陥密度の許容値は未だに示されてはいない。
また、光電変換特性と光起電力装置の生産性向上の両面
から、集積型光起電力装置を製造する際には、適正な非
晶質シリコン半導体膜の膜厚と裏面電極膜の膜厚の最適
な膜厚の関係が求められているが、このような最適値は
未だ示されていない。Under these conditions, in order to increase the production efficiency and reduce the thickness of the amorphous silicon semiconductor film and maintain high photoelectric conversion efficiency, it is necessary to use a high-quality i-layer having few defects. Although crystalline silicon is required, the allowable value of the defect density of i-layer amorphous silicon has not yet been shown.
In addition, when manufacturing an integrated photovoltaic device from the viewpoint of both the photoelectric conversion characteristics and the productivity improvement of the photovoltaic device, the appropriate film thickness of the amorphous silicon semiconductor film and the film thickness of the back electrode film are required. An optimum film thickness relationship is required, but such an optimum value has not yet been shown.
【００１３】本発明は、非晶質シリコンを用いた光起電
力装置において、高い光電変換効率を有し、透明電極膜
と金属電極間の高い絶縁抵抗を有することで、生産性の
優れた光起電力装置を提供することを目的に、ｉ層非晶
質シリコン膜の欠陥密度の許容値を示すとともに、適正
な半導体膜の厚さと金属電極膜の厚さとの関係を示し、
同時に、高性能な光起電力装置の製造方法を提供するこ
とを目的とする。The present invention relates to a photovoltaic device using amorphous silicon, which has high photoelectric conversion efficiency and high insulation resistance between a transparent electrode film and a metal electrode, thereby achieving excellent productivity. For the purpose of providing an electromotive force device, while showing the allowable value of the defect density of the i-layer amorphous silicon film, showing the relationship between the appropriate thickness of the semiconductor film and the thickness of the metal electrode film,
At the same time, an object is to provide a method for manufacturing a high-performance photovoltaic device.
【００１４】[0014]
【課題を解決するための手段】上記課題を解決するた
め、本発明の光起電力装置では、透明絶縁基板上に透明
電極膜、ｐｉｎ接合構造の非晶質シリコンからなる各半
導体膜、金属電極膜を順次積層して構成された光起電力
装置であって、該半導体膜の膜厚が２２０〜４００ｎｍ
であって、かつｉ層非晶質シリコン膜の欠陥密度が５×
１０15個／cm3 以下である光起電力装置とした。さらに
好ましくは、前記半導体膜の膜厚が２８０〜３８０ｎｍ
であって、かつｉ層非晶質シリコン膜の欠陥密度が１×
１０15個／cm3 以下とするのが良い。ｉ層非晶質シリコ
ン膜の欠陥密度を従来よりも１桁下げることにより、電
子−正孔対のトラップが減少して変換効率を高めること
ができるので、ｉ層非晶質シリコン膜の膜厚を薄くする
ことを可能にする。ｉ層非晶質シリコン膜の膜厚が薄く
なればそれだけ成膜時間が短縮され、生産性が向上して
発電コストを下げることが可能となる。ｉ層非晶質シリ
コン膜の欠陥密度が１×１０15個／cm3 以下となれば、
光劣化を１０％以下にすることができる。In order to solve the above problems, in the photovoltaic device of the present invention, a transparent electrode film, a semiconductor film made of amorphous silicon having a pin junction structure, and a metal electrode are formed on a transparent insulating substrate. A photovoltaic device configured by sequentially stacking films, wherein the semiconductor film has a thickness of 220 to 400 nm.
And the defect density of the i-layer amorphous silicon film is 5 ×
The photovoltaic device had a density of 10 15 / cm 3 or less. More preferably, the semiconductor film has a thickness of 280 to 380 nm.
And the defect density of the i-layer amorphous silicon film is 1 ×
It is better to be 10 15 / cm 3 or less. By lowering the defect density of the i-layer amorphous silicon film by an order of magnitude from the prior art, electron-hole pair traps can be reduced and conversion efficiency can be increased. Can be made thinner. As the film thickness of the i-layer amorphous silicon film becomes thinner, the film formation time is shortened accordingly, productivity is improved, and power generation cost can be reduced. When the defect density of the i-layer amorphous silicon film becomes 1 × 10 15 / cm 3 or less,
Light degradation can be reduced to 10% or less.
【００１５】また、本発明の光起電力装置は、前記半導
体膜の欠陥密度が低く厚さの薄い光起電力装置におい
て、前記半導体膜の膜厚（ｘ）と前記金属電極膜の膜厚
（ｙ）との関係が、ｉ層非晶質シリコン膜の膜厚を横軸
（ｘ軸）に金属電極膜の膜厚を縦軸（ｙ軸）に取った座
標軸において、点（ｘ、ｙ）がそれぞれＡ（２２０，２
００）、Ｂ（４００，２００）、Ｃ（４００，４０
０）、Ｄ（３４０，４００）であるＡＢＣＤ各点を結ん
だ範囲内にある光起電力装置とした。さらに好ましく
は、前記半導体膜の膜厚（ｘ）と前記金属電極膜の膜厚
（ｙ）との関係が、ｉ層半導体膜の膜厚を横軸（ｘ軸）
に金属電極膜の膜厚を縦軸（ｙ軸）に取った座標軸にお
いて、点（ｘ、ｙ）がそれぞれＥ（２８０，２００）、
Ｆ（３８０，２００）、Ｇ（３８０，４００）、Ｄ（３
４０，４００）、Ｈ（２８０，３００）であるＥＦＧＤ
Ｈ各点を結んだ範囲内にある光起電力装置である。積層
型光起電力装置を製造する際に、非晶質シリコン半導体
膜の膜厚が薄い分だけ水素の絶対量が少なくなるが、少
ないガス量の放出・膨張に見合う金属電極膜の膜厚とす
ることにより、レーザスクライブ時のバリ発生が抑制さ
れ、透明電極膜と金属電極膜間の高い絶縁抵抗が得ら
れ、良好な出力電力特性を達成することが可能となる。
半導体膜の膜厚と金属電極膜の膜厚との間に上記のよう
なバランスを保った上で、ｉ層非晶質シリコン膜の膜厚
をなるべく薄くできれば、それだけ生産性を高めること
が可能になる。In the photovoltaic device of the present invention, in the photovoltaic device having a low defect density of the semiconductor film and a small thickness, the thickness (x) of the semiconductor film and the thickness of the metal electrode film ( y), the point (x, y) on a coordinate axis where the thickness of the i-layer amorphous silicon film is taken on the horizontal axis (x-axis) and the thickness of the metal electrode film is taken on the vertical axis (y-axis). Are A (220, 2
00), B (400, 200), C (400, 40)
0) and a photovoltaic device within the range connecting the ABCD points of D (340, 400). More preferably, the relationship between the film thickness (x) of the semiconductor film and the film thickness (y) of the metal electrode film is such that the film thickness of the i-layer semiconductor film is expressed on the horizontal axis (x axis).
On a coordinate axis where the thickness of the metal electrode film is taken on the vertical axis (y-axis), points (x, y) are E (280, 200), respectively.
F (380,200), G (380,400), D (3
EFGD which is H (280,300)
H is a photovoltaic device within a range connecting each point. When manufacturing a stacked photovoltaic device, the absolute amount of hydrogen decreases as the thickness of the amorphous silicon semiconductor film decreases, but the thickness of the metal electrode film matches the release and expansion of a small amount of gas. By doing so, the occurrence of burrs at the time of laser scribing is suppressed, a high insulation resistance between the transparent electrode film and the metal electrode film is obtained, and good output power characteristics can be achieved.
If the thickness of the i-layer amorphous silicon film can be reduced as much as possible while maintaining the above balance between the thickness of the semiconductor film and the thickness of the metal electrode film, the productivity can be increased accordingly. become.
【００１６】本発明のもう一つの光起電力装置は、上述
の各光起電力装置を単位セルとして使用し、複数個の単
位セルを直列に接続した集積型光起電力装置である。高
性能な光起電力装置の単位セルを集積することにより、
外部取り出し電力の損失の少ない光起電力装置とするこ
とができる。単位セルとして利用する上述の各光起電力
装置は、レーザスクライブ加工に適した膜厚の非晶質シ
リコン半導体膜と金属電極膜を有しているので、加工中
にバリが発生する恐れも無く、歩留まり良く製造するこ
とができる。Another photovoltaic device of the present invention is an integrated photovoltaic device in which each of the above photovoltaic devices is used as a unit cell and a plurality of unit cells are connected in series. By integrating unit cells of high-performance photovoltaic devices,
A photovoltaic device with a small loss of externally extracted power can be obtained. Each of the above-described photovoltaic devices used as a unit cell has an amorphous silicon semiconductor film and a metal electrode film having a film thickness suitable for laser scribe processing, so that there is no possibility of generating burrs during the processing. , And can be manufactured with high yield.
【００１７】本発明の光起電力装置の製造方法は、透明
基板上に透明電極膜を形成する工程と、この透明電極膜
上にｐ層、ｉ層、ｎ層からなる非晶質シリコン半導体膜
を順次形成する工程と、このｎ層非晶質シリコン膜上に
金属電極膜を形成する工程とを具備した光起電力装置の
製造方法であって、前記ｉ層非晶質シリコン膜を形成す
るに際して、シランガス（ＳｉＨ4 ）を用いたプラズマ
ＣＶＤ法により、基板近傍に金属メッシュを配置し、該
金属メッシュを加熱することにより該ｉ層非晶質シリコ
ン膜の欠陥密度が５×１０15個／cm3 以下であるｉ層非
晶質シリコン膜を形成する光起電力装置の製造方法であ
る。金属メッシュを３００℃〜３５０℃に保つことによ
り、シランガスプラズマ中のラジカルが加熱されて、欠
陥密度が５×１０15個／cm3 以下の低欠陥密度を有する
良質なｉ層非晶質シリコン膜を形成することができる。
良質なｉ層非晶質シリコン膜は電力変換に必要な膜厚を
薄くすることを可能にし、生産性の向上に寄与する効果
を有する。According to the method of manufacturing a photovoltaic device of the present invention, a step of forming a transparent electrode film on a transparent substrate and an amorphous silicon semiconductor film comprising a p-layer, an i-layer, and an n-layer on the transparent electrode film And a step of forming a metal electrode film on the n-layer amorphous silicon film, wherein the i-layer amorphous silicon film is formed. At this time, a metal mesh was arranged near the substrate by a plasma CVD method using silane gas (SiH 4 ), and the metal mesh was heated so that the defect density of the i-layer amorphous silicon film was 5 × 10 15 / This is a method for manufacturing a photovoltaic device for forming an i-layer amorphous silicon film of not more than cm 3 . By maintaining the metal mesh at 300 ° C. to 350 ° C., the radicals in the silane gas plasma are heated, and a high-quality i-layer amorphous silicon film having a low defect density of 5 × 10 15 / cm 3 or less. Can be formed.
A high-quality i-layer amorphous silicon film can reduce the thickness required for power conversion, and has an effect of contributing to an improvement in productivity.
【００１８】また、本発明の光起電力装置の製造方法
は、透明基板上に透明電極膜を形成した後、該透明電極
膜にレーザビームを照射して切断して開溝を形成し、次
いで該開溝を含む透明電極膜上にｐ層、ｉ層、ｎ層から
なる非晶質シリコン半導体膜を順次形成した後、非晶質
シリコン膜にレーザービームを照射してコンタクト用開
口を形成し、続いて該コンタクト用開口部及び非晶質シ
リコン膜上に金属電極膜を形成し、しかる後に該透明基
板側からパルス幅が６０ｎｓ以下のレーザビームを照射
して前記非晶質シリコン膜と金属電極膜を切断して開口
部を形成し、複数の領域に分割された光起電力装置単位
セルが前記透明基板上で電気的に接続された集積型光起
電力装置の製造方法である。非晶質シリコン半導体膜の
膜厚が薄い分だけ水素の絶対量が少なくなるが、短いパ
ルス幅のレーザ光を用いることで、加工ビームの尖頭出
力が増加し、瞬間的にガスを放出・膨張させることがで
きる。そのため金属電極膜をちぎって吹き飛ばす効果が
高まり、バリ発生の抑制に有効で、その結果透明電極膜
と金属電極膜間の高い絶縁抵抗が得られ、良好な出力電
力特性を達成することが可能となる。Further, according to the method of manufacturing a photovoltaic device of the present invention, after forming a transparent electrode film on a transparent substrate, the transparent electrode film is irradiated with a laser beam and cut to form a groove. After an amorphous silicon semiconductor film composed of a p-layer, an i-layer, and an n-layer is sequentially formed on the transparent electrode film including the groove, a contact opening is formed by irradiating the amorphous silicon film with a laser beam. Forming a metal electrode film on the contact opening and the amorphous silicon film, and thereafter irradiating a laser beam having a pulse width of 60 ns or less from the transparent substrate side to the amorphous silicon film and the metal film; An opening is formed by cutting an electrode film, and a photovoltaic device unit cell divided into a plurality of regions is electrically connected on the transparent substrate to manufacture an integrated photovoltaic device. Although the absolute amount of hydrogen decreases as the thickness of the amorphous silicon semiconductor film decreases, the peak power of the processing beam increases by using a laser beam with a short pulse width, and gas is released instantaneously. Can be inflated. Therefore, the effect of breaking off and blowing off the metal electrode film is enhanced, which is effective in suppressing the generation of burrs.As a result, a high insulation resistance between the transparent electrode film and the metal electrode film is obtained, and it is possible to achieve good output power characteristics. Become.
【００１９】さらに、本発明の光起電力装置の製造方法
は、前記半導体膜の膜厚が２２０〜４００ｎｍであり、
ｉ層非晶質シリコン膜の欠陥密度が５×１０15個／cm3
以下であって、かつ金属電極膜の膜厚（ｙ）が、半導体
膜の膜厚を横軸（ｘ軸）に金属電極膜の膜厚を縦軸（ｙ
軸）に取った座標軸において、点（ｘ、ｙ）がそれぞれ
Ａ（２２０，２００）、Ｂ（４００，２００）、Ｃ（４
００，４００）、Ｄ（３４０，４００）であるＡＢＣＤ
各点を結んだ範囲内にある集積型光起電力装置の製造方
法である。高品質で薄いｉ層非晶質シリコン膜を使用し
て、適正な金属電極膜の膜厚を選択することにより、高
性能な特性を有する集積型光起電力装置を効率よく製造
することが可能となる。Further, in the method of manufacturing a photovoltaic device according to the present invention, the semiconductor film has a thickness of 220 to 400 nm,
The defect density of the i-layer amorphous silicon film is 5 × 10 15 defects / cm 3
The film thickness (y) of the metal electrode film is expressed as follows: the film thickness of the semiconductor film is represented by the horizontal axis (x axis), and the film thickness of the metal electrode film is represented by the vertical axis (y).
(X, y) on the coordinate axes taken as A (220, 200), B (400, 200), and C (4
00,400), ABCD that is D (340,400)
It is a method of manufacturing an integrated photovoltaic device within a range connecting each point. By using a high-quality thin i-layer amorphous silicon film and selecting an appropriate metal electrode film thickness, an integrated photovoltaic device with high-performance characteristics can be manufactured efficiently. Becomes
【００２０】[0020]
【発明の実施の形態】（第１実施形態）図１は本発明の
第１実施形態である光起電力装置の単位セルを示す図で
ある。この単位セル１０はガラス基板１上に透明電極膜
２と、ｉ層非晶質シリコン膜４をｐ層非晶質シリコン膜
３とｎ層非晶質シリコン膜５で挟んだｐｉｎ接合構造の
半導体膜６と、さらに金属電極膜７を順次積層して構成
してある。本発明では基板としてガラス、石英、透明樹
脂等の透明な絶縁性基板が使用できる。透明電極膜は、
酸化錫（ＳｎＯ2 ）、インジウム・錫酸化物（Ｉｎ・Ｓ
ｎＯ4：ＩＴＯ）または酸化亜鉛（ＺｎＯ：ＩＺＯ）等
の導電性金属酸化膜が使用できる。透明電極膜の厚さは
おおむね２００〜８００ｎｍ程度である。これら透明電
極膜の形成には、通常の熱ＣＶＤ法が利用できる。透明
電極膜の上には真性非晶質シリコン半導体膜（ｉ層）を
ｐ層不純物をドープしたｐ層非晶質シリコン膜と、ｎ層
不純物をドープしたｎ層非晶質シリコン膜とで挟んだ半
導体膜を積層する。この際、ｐ層非晶質シリコン膜の膜
厚はおおむね５〜１５ｎｍ、ｎ層非晶質シリコン膜の膜
厚はおおむね１０〜５０ｎｍとし、ｐｉｎ接合非晶質シ
リコン半導体膜の全膜厚は２２０〜４００ｎｍ、好まし
くは２８０〜３８０ｎｍとする。非晶質シリコン半導体
膜の膜厚が２２０ｎｍ未満では、発生する電子−正孔対
が少なく、発生電力が少ない上にピンホール等の欠陥を
生じやすい。一方、４００ｎｍを越えると光劣化による
光電変換特性の低下が顕著になる。FIG. 1 is a diagram showing a unit cell of a photovoltaic device according to a first embodiment of the present invention. The unit cell 10 is a semiconductor having a pin junction structure in which a transparent electrode film 2 and an i-layer amorphous silicon film 4 are sandwiched between a p-layer amorphous silicon film 3 and an n-layer amorphous silicon film 5 on a glass substrate 1. A film 6 and a metal electrode film 7 are sequentially laminated. In the present invention, a transparent insulating substrate such as glass, quartz, or transparent resin can be used as the substrate. The transparent electrode film
Tin oxide (SnO 2 ), indium tin oxide (In.S
A conductive metal oxide film such as nO 4 : ITO) or zinc oxide (ZnO: IZO) can be used. The thickness of the transparent electrode film is about 200 to 800 nm. A normal thermal CVD method can be used to form these transparent electrode films. On the transparent electrode film, an intrinsic amorphous silicon semiconductor film (i-layer) is sandwiched between a p-layer amorphous silicon film doped with a p-layer impurity and an n-layer amorphous silicon film doped with an n-layer impurity. Semiconductor films are stacked. At this time, the thickness of the p-layer amorphous silicon film is about 5 to 15 nm, the thickness of the n-layer amorphous silicon film is about 10 to 50 nm, and the total thickness of the pin junction amorphous silicon semiconductor film is 220 nm. To 400 nm, preferably 280 to 380 nm. When the thickness of the amorphous silicon semiconductor film is less than 220 nm, the number of generated electron-hole pairs is small, the generated power is small, and defects such as pinholes are easily generated. On the other hand, if it exceeds 400 nm, the deterioration of the photoelectric conversion characteristics due to light deterioration becomes remarkable.
【００２１】ｉ層非晶質シリコン半導体膜の欠陥密度
は、５×１０15個／cm3 以下とする。さらに好ましく
は、欠陥密度は、１×１０15個／cm3 以下であることが
望ましい。ｉ層非晶質シリコン膜の欠陥密度を従来より
も１桁下げることにより、電子−正孔対のトラップが減
少して光電変換効率を高めることができるので、ｉ層非
晶質シリコン膜の膜厚を薄くすることが可能になる。ｉ
層非晶質シリコン膜の膜厚を薄くできれば、成膜に要す
る時間が短縮でき、生産性の向上に寄与することができ
る。The defect density of the i-layer amorphous silicon semiconductor film is 5 × 10 15 defects / cm 3 or less. More preferably, the defect density is desirably 1 × 10 15 defects / cm 3 or less. By lowering the defect density of the i-layer amorphous silicon film by one digit compared to the conventional one, electron-hole pair traps can be reduced and the photoelectric conversion efficiency can be increased. The thickness can be reduced. i
If the thickness of the layered amorphous silicon film can be reduced, the time required for film formation can be shortened, which can contribute to improvement in productivity.
【００２２】このように欠陥密度の低いｉ層非晶質シリ
コン膜は、通常プラズマＣＶＤ法を使用して形成する。
ｐ層非晶質シリコン膜を形成するには、シランガス（Ｓ
ｉＨ4 ）、メタンガス（ＣＨ4 ）及びｐ層不純物元素ド
ーピング用のジボランガス（Ｂ2Ｈ6）を使用し、これら
の混合ガスがグロー放電分解することにより形成され
る。続いて同様な方法でシランガスを用いてｉ層非晶質
シリコン膜を形成する。このとき基板近傍に金属メッシ
ュを配置して３００〜３５０℃程度に加熱することによ
り低欠陥密度の良質なｉ層膜が形成できる。さらにシラ
ンガス（ＳｉＨ4 ）、水素ガス（Ｈ 2 ）及び ｎ層不純
物元素ドーピング用のホスフィンガス（ＰＨ3）を用い
て微結晶相を含むｎ層非晶質シリコン膜を形成する。As described above, the i-layer amorphous silicon having a low defect density is used.
The capacitor film is usually formed using a plasma CVD method.
To form a p-layer amorphous silicon film, silane gas (S
iHFour ), Methane gas (CHFour ) And p-layer impurity element
Diborane gas (BTwoH6) Use these
Formed by glow discharge decomposition
You. Subsequently, the i-layer is amorphous using silane gas in the same manner.
A silicon film is formed. At this time, a metal mesh near the substrate
By placing the heating and heating to about 300 to 350 ° C
A high-quality i-layer film having a low defect density can be formed. More shira
Gas (SiHFour ), Hydrogen gas (H Two ) And n-layer impurities
Phosphine gas (PHThree)
To form an n-layer amorphous silicon film containing a microcrystalline phase.
【００２３】図４に従来の通常のプラズマＣＶＤ製膜法
で製膜された、ｉ層膜の欠陥密度が５×１０16個／ｃｍ
3 の非晶質シリコン膜を用いたときの非晶質シリコン膜
の膜厚と規格化効率の関係を示す。非晶質シリコンの膜
厚が４００ｎｍのときの太陽電池の初期効率を１とした
とき、時間が経過した光劣化後の安定化効率をみると効
率が２０％低下している。非晶質シリコンの膜厚が増加
するほど規格化効率は上昇するが、光劣化後の安定化効
率は逆に低下してくる。FIG. 4 shows that the defect density of the i-layer film formed by the conventional ordinary plasma CVD film forming method is 5 × 10 16 defects / cm.
The relationship between the thickness of the amorphous silicon film and the standardization efficiency when the amorphous silicon film of No. 3 is used is shown. Assuming that the initial efficiency of the solar cell when the thickness of the amorphous silicon film is 400 nm is 1, the efficiency of the stabilization after photodegradation with the passage of time is reduced by 20%. As the film thickness of amorphous silicon increases, the standardization efficiency increases, but the stabilization efficiency after photodegradation decreases.
【００２４】一方、金属メッシュによるラジカルヒータ
ーを用いて非晶質シリコン膜を製膜した、本発明で使用
する非晶質シリコン膜の場合、ｉ層膜の欠陥密度が５×
１０ 15個／ｃｍ3 以下になり、図５に示すように非晶質
シリコン膜の膜厚が３４０ｎｍのとき、従来と同等の初
期効率（規格化効率１）が得られ、安定化効率は１２％
の低下に留まることが判った。またｉ層膜の欠陥密度が
１×１０15個／ｃｍ3以下のときは、図６に示すように
非晶質シリコン膜の膜厚が３２０ｎｍのとき、従来と同
等の初期効率（規格化効率１）が得られ、光劣化後の安
定化効率の低下は１０％と低くなることが判明した。太
陽電池においては時間が経過して光劣化を起こすことは
避けられないが、ｉ層非晶質シリコンの欠陥密度を低く
して半導体膜の膜厚を２２０〜４００ｎｍに設定してお
けば、安定化効率は０．７５以上を確保できることが判
る。さらに好ましい太陽電池特性（高い安定化効率）を
得るには半導体膜の膜厚は２８０〜３８０ｎｍとするの
が良い。On the other hand, a radical heater using a metal mesh
Amorphous silicon film is formed by using
In the case of an amorphous silicon film, the defect density of the i-layer film is 5 ×
10 FifteenPieces / cmThree Below, as shown in FIG.
When the thickness of the silicon film is 340 nm, the initial
Initial efficiency (standardization efficiency 1) is obtained, and stabilization efficiency is 12%
Was found to remain at a lower level. Also, the defect density of the i-layer film is
1 × 10FifteenPieces / cmThreeIn the following cases, as shown in FIG.
When the thickness of the amorphous silicon film is 320 nm,
The initial efficiency (standardized efficiency 1) is obtained.
It was found that the decrease in the stabilization efficiency was as low as 10%. Thick
Photodegradation of solar cells over time
Although unavoidable, the defect density of the i-layer amorphous silicon is reduced.
And set the thickness of the semiconductor film to 220 to 400 nm.
It can be seen that the stabilization efficiency can secure 0.75 or more.
You. More favorable solar cell characteristics (high stabilization efficiency)
In order to obtain, the thickness of the semiconductor film should be 280 to 380 nm.
Is good.
【００２５】金属電極膜は、電気比抵抗の低いアルミニ
ウム（Ａｌ）や銀（Ａｇ）を使用する。金属電極膜の膜
厚は前記ｉ層非晶質シリコン膜の膜厚に応じて適正な厚
さに形成する。すなわち、金属電極膜の膜厚は、主とし
て後述する集積型光起電力装置をレーザスクライブ加工
する際のバリ等の発生を抑制する観点から決められる。
欠陥密度が５×１０15個／ｃｍ3 のｉ層非晶質シリコン
膜を用いた時、金属電極膜の最適膜厚は、パルス幅６０
ｎｓのレーザを使用してスクライブした後、透明電極膜
と金属電極膜間の絶縁抵抗（電極面積０．２５ｃｍ2 、
印加電圧０．１Ｖ時）が１０ｋΩ以上になる条件を満た
す範囲で決定される。その結果、金属電極膜の膜厚は、
半導体膜の膜厚を（ｘ）とし金属電極膜の膜厚（ｙ）と
して、半導体膜の膜厚を横軸（ｘ軸）に金属電極膜の膜
厚を縦軸（ｙ軸）に取った座標軸において、透明電極膜
と金属電極膜間の絶縁抵抗が１０ｋΩ以上になるｘ、ｙ
をプロットしてみたところ、点（ｘ、ｙ）がそれぞれＡ
（２２０，２００）、Ｂ（４００，２００）、Ｃ（４０
０，４００）、Ｄ（３４０，４００）であるＡＢＣＤ各
点を結んだ範囲内にあることが判明した。この関係を図
７に示す。As the metal electrode film, aluminum (Al) or silver (Ag) having a low electric resistivity is used. The metal electrode film is formed to have an appropriate thickness according to the thickness of the i-layer amorphous silicon film. That is, the thickness of the metal electrode film is determined mainly from the viewpoint of suppressing the occurrence of burrs and the like when performing laser scribing of an integrated photovoltaic device described later.
When an i-layer amorphous silicon film having a defect density of 5 × 10 15 / cm 3 is used, the optimum thickness of the metal electrode film is a pulse width of 60
After scribing using a laser of ns, the insulation resistance between the transparent electrode film and the metal electrode film (electrode area 0.25 cm 2 ,
(At an applied voltage of 0.1 V) is determined within a range that satisfies the condition of becoming 10 kΩ or more. As a result, the thickness of the metal electrode film is
Assuming that the thickness of the semiconductor film is (x) and the thickness of the metal electrode film is (y), the thickness of the semiconductor film is plotted on the horizontal axis (x-axis) and the thickness of the metal electrode film is plotted on the vertical axis (y-axis). X, y on the coordinate axis where the insulation resistance between the transparent electrode film and the metal electrode film becomes 10 kΩ or more.
Was plotted, and the points (x, y) were A
(220, 200), B (400, 200), C (40
0,400) and D (340,400) within the range connecting the ABCD points. This relationship is shown in FIG.
【００２６】金属電極膜の膜厚が２００ｎｍ未満では、
非晶質シリコンの膜厚がいずれの場合でも絶縁抵抗は１
０ｋΩ程度であるがＡｌなどの酸化し易い金属膜を用い
た時、絶縁酸化膜が生成するため実効膜厚が小さくな
り、金属電極膜そのものの抵抗分が無視できなくなるた
め不適当である。また金属電極膜の膜厚が４００ｎｍを
越えるとレーザスクライブ加工の際に金属のバリが生じ
やすく、このバリが透明電極に接触すると絶縁抵抗が低
下する。半導体膜が薄くなるにつれ結合水素が減少する
ためバリが生じやすくなる。従って、金属電極膜の膜厚
は２００ｎｍ〜４００ｎｍの範囲であって、かつ上記四
辺形ＡＢＣＤの範囲内とすれば良い。金属電極膜の膜厚
をこのように半導体膜の膜厚との関係で設定しおけば、
バリが発生しないために加工後の洗浄が不要となり、形
状因子は０．６５以上と良好な太陽電池特性を示す。When the thickness of the metal electrode film is less than 200 nm,
The insulation resistance is 1 regardless of the thickness of the amorphous silicon.
When a metal film that is easily oxidized, such as Al, having a thickness of about 0 kΩ is used, an insulating oxide film is formed, the effective film thickness is reduced, and the resistance of the metal electrode film itself cannot be ignored. On the other hand, if the thickness of the metal electrode film exceeds 400 nm, metal burrs are likely to occur during laser scribing, and if the burrs come into contact with the transparent electrode, the insulation resistance decreases. As the thickness of the semiconductor film becomes thinner, the amount of bonded hydrogen decreases, so that burrs tend to occur. Accordingly, the thickness of the metal electrode film may be in the range of 200 nm to 400 nm and within the range of the above-mentioned quadrilateral ABCD. If the thickness of the metal electrode film is set in this way in relation to the thickness of the semiconductor film,
Since no burrs are generated, cleaning after processing is not required, and the shape factor is 0.65 or more, which shows good solar cell characteristics.
【００２７】さらに好ましくは、前記の座標軸におい
て、点（ｘ、ｙ）がそれぞれＥ（２８０，２００）、Ｆ
（３８０，２００）、Ｇ（３８０，４００）、Ｄ（３４
０，４００）、Ｈ（２８０，３００）であるえＥＦＧＤ
Ｈ各点を結んだ範囲内にあることが望ましい。ｉ層非晶
質シリコン膜の膜厚と金属電極膜の膜厚とがＥＦＧＤＨ
各点を結んだ範囲内にあれば、絶縁抵抗は１５ｋΩ以
上，形状因子は０．６８以上のより好ましい太陽電池特
性が得られる。このＥＦＧＤＨ各点の関係を図８に示
す。More preferably, on the coordinate axes, points (x, y) are E (280, 200) and F (280), respectively.
(380, 200), G (380, 400), D (34
0,400), H (280,300) EFGD
It is desirable that H be within the range connecting the points. The thickness of the i-layer amorphous silicon film and the thickness of the metal electrode film are EFGDH
Within the range connecting the points, more preferable solar cell characteristics with an insulation resistance of 15 kΩ or more and a shape factor of 0.68 or more can be obtained. FIG. 8 shows the relationship between the respective points of the EFGDH.
【００２８】（第２実施形態）次に第２の実施形態とし
て、第１の実施形態で示した光起電力装置の単位セル
を、基板上で複数個電気的に直列に接続した集積型の光
起電力装置について説明する。集積型の光起電力装置の
単位セルは第１の実施形態で示したものと同じであるの
で、主として単位セル同志の接続方法を中心とした集積
型の光起電力装置の形成方法について説明する。図３に
集積型の光起電力装置の形成方法主要な工程図を示す。
先ず、図３（ａ）に示すように第１の実施形態と同様
に、透明絶縁性のガラス基板１１上に熱ＣＶＤ装置を用
いて透明電極膜１２を成膜する。使用できるガラス基板
１１は第１の実施形態と同様であるが、基板の大きさは
複数の単位セルを形成するのに充分な大きさとする。透
明電極膜１２は第１の実施形態と同様である。(Second Embodiment) Next, as a second embodiment, an integrated type in which a plurality of unit cells of the photovoltaic device shown in the first embodiment are electrically connected in series on a substrate. The photovoltaic device will be described. Since the unit cells of the integrated photovoltaic device are the same as those shown in the first embodiment, a method of forming the integrated photovoltaic device will be mainly described focusing on the connection method of the unit cells. . FIG. 3 shows a main process chart of a method of forming an integrated photovoltaic device.
First, as shown in FIG. 3A, a transparent electrode film 12 is formed on a transparent insulating glass substrate 11 using a thermal CVD apparatus, as in the first embodiment. The glass substrate 11 that can be used is the same as that of the first embodiment, but the size of the substrate is set to be large enough to form a plurality of unit cells. The transparent electrode film 12 is the same as in the first embodiment.
【００２９】次に、透明電極膜１２を形成した後、その
透明電極膜１２に例えばＹＡＧレーザを用いレーザビー
ムスクライブして開溝１８を形成する。開溝１８は透明
電極膜１２を電気的に切断分離できればよいので、レー
ザビームを使用してなるべく狭い間隔、例えば約１００
μｍ以下とする。例えば、レーザ波長は１０６４ｎｍ、
ビーム径は４０μｍ、レーザパワー密度は２×１０5 Ｗ
／ｃｍ2 程度が適当である。レーザビームはＹＡＧレー
ザの他に炭酸ガスレーザも使用できる。Next, after the transparent electrode film 12 is formed, a groove 18 is formed in the transparent electrode film 12 by laser beam scribing using, for example, a YAG laser. The grooves 18 need only be capable of electrically cutting and separating the transparent electrode film 12, so that the distance between the grooves 18 is as small as possible using a laser beam, for example, about 100 nm.
μm or less. For example, the laser wavelength is 1064 nm,
The beam diameter is 40 μm and the laser power density is 2 × 10 5 W
/ Cm 2 is appropriate. As the laser beam, a carbon dioxide laser can be used in addition to the YAG laser.
【００３０】続いて図３（ｂ）に示すようにｐｉｎ接合
構造からなる非晶質シリコンの半導体膜１６をプラズマ
ＣＶＤ装置を用いて基板全面に形成する。これらｐｉｎ
接合構造からなる非晶質シリコンの半導体膜の形成も、
第１の実施形態と同様で良い。すなわち、真性非晶質シ
リコン半導体膜（ｉ層）をｐ層不純物をドープしたｐ層
非晶質シリコン膜と、ｎ層不純物をドープしたｎ層非晶
質シリコン膜とで挟んだ半導体層を積層する。この際、
ｐ層非晶質シリコン膜の膜厚はおおむね５〜１５ｎｍ、
ｎ層非晶質シリコン膜の膜厚はおおむね１０〜５０ｎｍ
とし、ｐｉｎ接合非晶質シリコン半導体膜の全膜厚は２
２０〜４００ｎｍ、好ましくは２８０〜３８０ｎｍとす
る。非晶質シリコン半導体膜の膜厚が２２０ｎｍ未満で
は、発生する電子−正孔対が少なく、発生電力が少ない
上にピンホール等の欠陥を生じやすい。一方、４００ｎ
ｍを越えると光劣化による変換特性の低下が顕著にな
る。Subsequently, as shown in FIG. 3B, an amorphous silicon semiconductor film 16 having a pin junction structure is formed on the entire surface of the substrate by using a plasma CVD apparatus. These pins
The formation of a semiconductor film of amorphous silicon having a junction structure also
This may be the same as in the first embodiment. That is, a semiconductor layer in which an intrinsic amorphous silicon semiconductor film (i-layer) is sandwiched between a p-layer amorphous silicon film doped with a p-layer impurity and an n-layer amorphous silicon film doped with an n-layer impurity is laminated. I do. On this occasion,
The thickness of the p-layer amorphous silicon film is approximately 5 to 15 nm,
The thickness of the n-layer amorphous silicon film is approximately 10 to 50 nm
And the total thickness of the pin junction amorphous silicon semiconductor film is 2
20 to 400 nm, preferably 280 to 380 nm. When the thickness of the amorphous silicon semiconductor film is less than 220 nm, the number of generated electron-hole pairs is small, the generated power is small, and defects such as pinholes are easily generated. On the other hand, 400n
If m is exceeded, the conversion characteristics will be significantly reduced due to light degradation.
【００３１】ｉ層非晶質シリコン半導体膜の欠陥密度
は、５×１０15個／cm3 以下、より好ましくは１×１０
15個／cm3 以下であることが望ましい。ｉ層非晶質シリ
コン膜の欠陥密度を低くすることにより、電子−正孔対
のトラップが減少して光電変換効率を高めることができ
るので、ｉ層非晶質シリコン膜の膜厚を薄くすることが
可能になる。ｉ層非晶質シリコン膜の膜厚を薄くできれ
ば、成膜に要する時間が短縮でき、生産性の向上に寄与
することができる。The defect density of the i-layer amorphous silicon semiconductor film is 5 × 10 15 / cm 3 or less, more preferably 1 × 10 15 / cm 3.
It is desirable that the number be 15 or less / cm 3 or less. By lowering the defect density of the i-layer amorphous silicon film, electron-hole pair traps can be reduced and the photoelectric conversion efficiency can be increased. Therefore, the thickness of the i-layer amorphous silicon film is reduced. It becomes possible. If the thickness of the i-layer amorphous silicon film can be reduced, the time required for film formation can be shortened, which can contribute to improvement in productivity.
【００３２】次に、半導体膜１６に例えばＹＡＧレーザ
を照射して、半導体膜１６をレーザスクライブしてコン
タクト部開口１９を形成する。コンタクト部開口１９は
ガラス基板１１の全面に形成した半導体膜１６を分離し
て単位セルを形成するためのものであり、幅はやや広
く、おおむね１００μｍ程度とする。レーザ波長は１０
６４ｎｍ、ビーム径は１００μｍ、レーザパワー密度は
１．５×１０4 Ｗ／ｃｍ 2 程度が適当である。Next, for example, a YAG laser
And scribe the semiconductor film 16 by laser scribing.
The tact opening 19 is formed. The contact opening 19 is
The semiconductor film 16 formed on the entire surface of the glass substrate 11 is separated.
To form a unit cell.
Approximately 100 μm. Laser wavelength is 10
64 nm, beam diameter 100 μm, laser power density
1.5 × 10Four W / cm Two The degree is appropriate.
【００３３】続いて図３（ｃ）に示すように、基板全面
に裏面電極膜１７となる金属膜を成膜する。この金属膜
の種類や成膜方法も第１の実施形態と同様で良い。すな
わち、裏面電極膜１７の膜厚は半導体膜の膜厚との関連
で設定する。裏面電極基板となる金属電極膜の膜厚
（ｙ）は図７に示すように、半導体膜の膜厚を（ｘ）と
し、半導体膜の膜厚を横軸（ｘ軸）に金属電極膜の膜厚
を縦軸（ｙ軸）に取った座標軸において、点（ｘ、ｙ）
がそれぞれＡ（２２０，２００）、Ｂ（４００，２０
０）、Ｃ（４００，４００）、Ｄ（３４０，４００）で
あるＡＢＣＤ各点を結んだ範囲内に設定する。より好ま
しくは図８に示すように、前記の座標軸において点
（ｘ、ｙ）がそれぞれＥ（２８０，２００）、Ｆ（３８
０，２００）、Ｇ（３８０，４００）、Ｄ（３４０，４
００）、Ｈ（２８０，３００）であるＥＦＧＤＨ各点を
結んだ範囲内にあるように設定する。Subsequently, as shown in FIG. 3C, a metal film to be the back electrode film 17 is formed on the entire surface of the substrate. The type of the metal film and the film forming method may be the same as in the first embodiment. That is, the thickness of the back electrode film 17 is set in relation to the thickness of the semiconductor film. As shown in FIG. 7, the thickness (y) of the metal electrode film serving as the back electrode substrate is represented by (x) where the thickness of the semiconductor film is represented by (x), and the thickness of the semiconductor film is represented by the horizontal axis (x-axis). On a coordinate axis with the film thickness taken on the vertical axis (y axis), a point (x, y)
Are A (220, 200) and B (400, 20
0), C (400, 400) and D (340, 400) are set within the range connecting the ABCD points. More preferably, as shown in FIG. 8, points (x, y) on the coordinate axes are E (280, 200) and F (38, respectively).
0, 200), G (380, 400), D (340, 4)
00) and H (280, 300) are set so as to be within the range connecting the EFGDH points.
【００３４】金属電極膜の膜厚をこのように設定すれ
ば、レーザスクライブ加工の際に金属のバリが生ずるこ
ともなく、バリが透明電極に接触して絶縁抵抗が低下す
ることも無い。バリが発生しないために加工後の洗浄も
不要となり、太陽電池形状因子は０．６５以上の良好な
太陽電池特性が得られる。When the thickness of the metal electrode film is set in this manner, no metal burrs are generated during laser scribing, and the burrs do not contact the transparent electrode to lower the insulation resistance. Since no burrs are generated, cleaning after processing is not required, and good solar cell characteristics with a solar cell shape factor of 0.65 or more can be obtained.
【００３５】金属電極膜を形成する前に、非晶質シリコ
ン膜上に７０〜１００ｎｍのＺｎＯまたはＩＴＯ等の透
明金属酸化物を挿入してもよい。透明金属酸化物を挿入
することにより、非晶質シリコン膜と金属電極膜との接
触抵抗を下げることが可能となる。非晶質シリコン膜上
に透明金属酸化物を挿入しても、金属膜のレーザスクラ
イブ加工に必要なレーザパワーにはほとんど影響を与え
ない。Before forming the metal electrode film, a transparent metal oxide such as ZnO or ITO of 70 to 100 nm may be inserted on the amorphous silicon film. By inserting the transparent metal oxide, the contact resistance between the amorphous silicon film and the metal electrode film can be reduced. Even if a transparent metal oxide is inserted on the amorphous silicon film, the laser power required for laser scribe processing of the metal film is hardly affected.
【００３６】続いてガラス基板側からＹＡＧレーザ等の
レーザビームを照射して、金属電極膜をレーザスクライ
ブし開口部２０を形成する。この時、ガラス基板側から
レーザービームを照射するので、少ないレーザパワーで
スクライブ加工ができる。この基板側からのレーザビー
ム照射法の場合、透明なガラス基板及び透明電極膜を透
過したレーザビームが半導体膜で吸収されて熱に変わる
ときに、半導体膜内の多量の結合水素の分解ガスの膨張
によって金属電極膜がちぎられて吹き飛ばされるメカニ
ズムでスクライブが進行する。従って半導体膜の膜厚に
見合った金属電極膜の厚さにしておかないと、綺麗なス
クライブ面が得られない。前述の通り非晶質シリコンか
らなる半導体膜の厚さは光起電力の変換効率の面から最
適値が与えられており、最適な半導体膜の膜厚に対応す
る金属電極膜の厚さは、前述の図７又は図８に示したと
おりである。第２電極膜の厚さが前述の図７又は図８に
示した適正範囲内にある限り、第２電極膜のレーザビー
ムスクライブによって加工不良（バリ）が発生すること
はない。Subsequently, a laser beam such as a YAG laser is irradiated from the glass substrate side, and the metal electrode film is laser scribed to form an opening 20. At this time, since the laser beam is irradiated from the glass substrate side, scribe processing can be performed with a small laser power. In the case of this laser beam irradiation method from the substrate side, when the laser beam transmitted through the transparent glass substrate and the transparent electrode film is absorbed by the semiconductor film and converted into heat, a large amount of the decomposition gas of the bonded hydrogen in the semiconductor film is generated. The scribing proceeds by a mechanism in which the metal electrode film is torn off and blown off by the expansion. Therefore, unless the thickness of the metal electrode film is adjusted to the thickness of the semiconductor film, a clean scribe surface cannot be obtained. As described above, the thickness of the semiconductor film made of amorphous silicon is given an optimum value in terms of the photovoltaic conversion efficiency, and the thickness of the metal electrode film corresponding to the optimum thickness of the semiconductor film is This is as shown in FIG. 7 or FIG. As long as the thickness of the second electrode film is within the appropriate range shown in FIG. 7 or FIG. 8, processing defects (burrs) do not occur due to laser beam scribing of the second electrode film.
【００３７】半導体膜の膜厚が３４０ｎｍ、金属電極膜
の膜厚が３００ｎｍである、上記の適正な膜厚範囲内に
ある代表的な積層構造体を用いて、パルス幅が１３０ｎ
ｓのＹＡＧレーザビームをガラス基板側から照射して、
金属電極膜をレーザビームスクライブして開溝を形成さ
せたところ、バリが生じて透明電極膜と金属電極膜との
間の絶縁抵抗は２ｋΩを示した。これを水中で超音波洗
浄したところバリが除去されて絶縁抵抗は1５kΩ以上に
増加した。このように半導体膜の膜厚が４００ｎｍ以下
の場合、水素の絶対量不足から長いパルス幅のレーザを
使用するとバリが生じる。この対策としてパルス幅が６
０ｎｓ以下の短いパルス幅のレーザビームを使用する
と、加工ビームの尖頭出力が増加し、瞬間的にガスを放
出・膨張させることができる。そのため金属電極膜をち
ぎって吹き飛ばす能力が高まり、バリの発生を抑制する
ことができる。その結果透明電極膜と金属電極膜間の高
い絶縁抵抗が得られ、良好な出力電力特性を達成するこ
とが可能となる。金属電極膜のレーザビームスクライブ
に使用するレーザ波長は１０６４ｎｍまたは５３２ｎ
ｍ、ビーム径は５０〜１００μｍ、レーザパワー密度は
７×１０3Ｗ／ｃｍ2 、レーザパルス幅は６０ｎｓ程度
が適当である。Using a typical laminated structure having the thickness of the semiconductor film of 340 nm and the thickness of the metal electrode film of 300 nm within the above-mentioned appropriate thickness range, the pulse width is 130 n.
s YAG laser beam from the glass substrate side,
When the groove was formed by laser beam scribing the metal electrode film, burrs were generated and the insulation resistance between the transparent electrode film and the metal electrode film was 2 kΩ. When this was subjected to ultrasonic cleaning in water, burrs were removed and the insulation resistance increased to 15 kΩ or more. As described above, when the thickness of the semiconductor film is 400 nm or less, burrs occur when a laser having a long pulse width is used due to a shortage of the absolute amount of hydrogen. As a countermeasure against this, a pulse width of 6
When a laser beam having a short pulse width of 0 ns or less is used, the peak power of the processing beam increases, and the gas can be released and expanded instantaneously. Therefore, the ability to tear off the metal electrode film is enhanced, and the occurrence of burrs can be suppressed. As a result, a high insulation resistance between the transparent electrode film and the metal electrode film is obtained, and good output power characteristics can be achieved. Laser wavelength used for laser beam scribe of metal electrode film is 1064 nm or 532 n
m, the beam diameter is 50 to 100 μm, the laser power density is 7 × 10 3 W / cm 2 , and the laser pulse width is suitably about 60 ns.
【００３８】[0038]
【作用】本発明は、発電層となる半導体膜の品質を改善
し、その厚さを２２０〜４００ｎｍと薄くし、半導体膜
の膜厚に見合った適正な厚さの金属電極膜で単位セルを
構成することにより、変換効率に優れ、しかも生産性が
高い光起電力装置を提供するものである。ｉ層非晶質シ
リコン膜の欠陥密度を５×１０15個／ｃｍ 3以下とすれ
ば、光電変換効率を損なわずにｉ層非晶質シリコン膜の
膜厚を薄くすることができる。ｉ層非晶質シリコン膜の
膜厚を薄くした結果、光劣化を抑えることもできる。金
属電極膜の切断には透明基板側から短いパルス幅のレー
ザビームを照射することにより、バリの発生を防止して
絶縁抵抗の高い光起電力装置を得ることができる。その
結果、集積型光起電力装置を高い生産効率の下に製造す
ることができる。ｉ層非晶質シリコン膜の膜厚を薄くす
れば成膜時間が短縮でき、生産性が向上する結果発電コ
ストを下げることが可能となる。According to the present invention, the quality of a semiconductor film to be a power generation layer is improved, the thickness is reduced to 220 to 400 nm, and a unit cell is formed with a metal electrode film having an appropriate thickness corresponding to the thickness of the semiconductor film. With this configuration, a photovoltaic device having excellent conversion efficiency and high productivity is provided. When the defect density of the i-layer amorphous silicon film is 5 × 10 15 / cm 3 or less, the thickness of the i-layer amorphous silicon film can be reduced without impairing the photoelectric conversion efficiency. As a result of reducing the thickness of the i-layer amorphous silicon film, light degradation can also be suppressed. By irradiating a laser beam with a short pulse width from the transparent substrate side for cutting the metal electrode film, it is possible to prevent generation of burrs and obtain a photovoltaic device having high insulation resistance. As a result, the integrated photovoltaic device can be manufactured with high production efficiency. If the thickness of the i-layer amorphous silicon film is reduced, the film formation time can be shortened, and the productivity is improved, so that the power generation cost can be reduced.
【００３９】[0039]
【実施例】以下実施例と比較例を用いて本発明をより具
体的に説明する。 （実施例１）ガラス基板上に熱ＣＶＤ装置を用いて透明
電極膜としてＳｎＯ2 からなる透明電極膜を厚さ７００
ｎｍに成膜した。続いてｐｉｎ接合構造の非晶質シリコ
ンの半導体薄膜をプラズマＣＶＤ装置を用いて基板全面
に形成した。ｐ層非晶質シリコン膜はシランガス（Ｓｉ
Ｈ4 ）、メタンガス（ＣＨ4 ）及びｐ層不純物元素ドー
ピング用のジボランガス（Ｂ2Ｈ6）を使用したグロー放
電分解により形成した。膜厚は１０ｎｍとした。続いて
同様な方法でシランガスを用いてｉ層非晶質シリコン膜
を形成した。このとき基板近傍に金属メッシュを配置し
て３３０℃に加熱することによりシランガスプラズマ中
に発生したラジカルを利用して、低欠陥密度の良質なｉ
層非晶質シリコン膜を形成した。得られたｉ層非晶質シ
リコン膜を一定光電流測定装置（ＣＰＭ）にかけ、膜中
の欠陥密度を測定した結果、欠陥密度は５×１０15個／
ｃｍ3 であった。さらにシランガス（ＳｉＨ4 ）、水素
ガス（Ｈ2 ）及びｎ層不純物元素ドーピング用のホスフ
ィンガス（ＰＨ3 ）を用いて微結晶相を含むｎ層非晶質
シリコン膜を厚さ２０ｎｍに形成した。この結果、非晶
質シリコン膜の全膜厚は３４０ｎｍとなった。The present invention will be described more specifically with reference to the following examples and comparative examples. Example 1 A transparent electrode film made of SnO 2 was formed on a glass substrate to a thickness of 700 using a thermal CVD apparatus as a transparent electrode film.
nm. Subsequently, a semiconductor thin film of amorphous silicon having a pin junction structure was formed over the entire surface of the substrate by using a plasma CVD apparatus. The p-layer amorphous silicon film is made of silane gas (Si
H 4 ), methane gas (CH 4 ), and diborane gas (B 2 H 6 ) for doping a p-layer impurity element were formed by glow discharge decomposition. The film thickness was 10 nm. Subsequently, an i-layer amorphous silicon film was formed using a silane gas in the same manner. At this time, a metal mesh is arranged in the vicinity of the substrate and heated to 330 ° C. to utilize the radicals generated in the silane gas plasma to obtain a low-density high-quality i.
A layer amorphous silicon film was formed. The obtained i-layer amorphous silicon film was subjected to a constant photocurrent measuring device (CPM) and the defect density in the film was measured. As a result, the defect density was 5 × 10 15 /
cm 3 . Further, an n-layer amorphous silicon film containing a microcrystalline phase was formed to a thickness of 20 nm using silane gas (SiH 4 ), hydrogen gas (H 2 ) and phosphine gas (PH 3 ) for doping the n-layer impurity element. As a result, the total thickness of the amorphous silicon film became 340 nm.
【００４０】続いて、金属電極膜となる厚さ２５０ｎｍ
のアルミニウム（Ａｌ）膜を基板全面に真空蒸着して形
成した。以上の工程により図１に示す積層構造の光起電
力装置を得た。得られた光起電力装置の初期効率を１に
規格化したとき、安定化効率は０．８８（低下率：１２
％）、透明電極と金属電極との間の絶縁抵抗は１５ｋΩ
以上、太陽電池形状因子は０．６８以上であった。ま
た、同じ厚さの金属電極を用い、半導体膜の膜厚を２６
０ｎｍとしたときに、前述の初期効率を１としたときの
初期効率は０．８６、安定化効率は０．８（低下率：７
％）であった。また、透明電極と金属電極との間の絶縁
抵抗は１０ｋΩ以上、太陽電池形状因子は０．６５以上
であった。Subsequently, a 250 nm-thick metal electrode film is formed.
Was formed by vacuum evaporation of an aluminum (Al) film on the entire surface of the substrate. Through the above steps, a photovoltaic device having a laminated structure shown in FIG. 1 was obtained. When the initial efficiency of the obtained photovoltaic device was normalized to 1, the stabilization efficiency was 0.88 (decrease rate: 12
%), The insulation resistance between the transparent electrode and the metal electrode is 15 kΩ
As described above, the solar cell form factor was 0.68 or more. Further, the same thickness of metal electrode is used, and the thickness of the semiconductor film is set to 26.
When the initial efficiency is set to 1, the initial efficiency is 0.86, and the stabilization efficiency is 0.8 (decrease rate: 7).
%)Met. Further, the insulation resistance between the transparent electrode and the metal electrode was 10 kΩ or more, and the solar cell form factor was 0.65 or more.
【００４１】（実施例２）欠陥密度が１×１０15 個／
ｃｍ3以下のｉ層非晶質シリコン膜を使用して、ｉ層非
晶質シリコン膜の膜厚と金属電極膜の膜厚を変えた以外
は、実施例１と同様にして光起電力装置を製造した。す
なわち、ｉ層非晶質シリコン膜欠陥密度は１×１０15
個／ｃｍ3、半導体膜厚は３２０ｎｍ、金属電極膜の膜
厚は３００ｎｍとした。得られた光起電力装置の初期効
率は１、安定化効率は０．９（低下率：１０％）、透明
電極と金属電極との間の絶縁抵抗は１５ｋΩ以上、太陽
電池形状因子は０．６８以上であり、さらに高性能な光
起電力装置が得られた。Example 2 The defect density was 1 × 10 15 defects /
Photovoltaic device in the same manner as in Example 1 except that the thickness of the i-layer amorphous silicon film and the thickness of the metal electrode film were changed using an i-layer amorphous silicon film of cm 3 or less. Was manufactured. That is, the defect density of the i-layer amorphous silicon film is 1 × 10 15
Pieces / cm 3 , the semiconductor film thickness was 320 nm, and the metal electrode film thickness was 300 nm. The obtained photovoltaic device has an initial efficiency of 1, a stabilization efficiency of 0.9 (decrease rate: 10%), an insulation resistance between the transparent electrode and the metal electrode of 15 kΩ or more, and a solar cell shape factor of 0.1. A value of 68 or more was obtained, and a higher performance photovoltaic device was obtained.
【００４２】（比較例１）通常のプラズマＣＶＤ法によ
り得た欠陥密度が５×１０16個／ｃｍ3 のｉ層非晶質シ
リコン膜を使用して、半導体膜の膜厚を４５０ｎｍ、金
属電極膜の膜厚を４２０ｎｍとして、実施例１と同様な
積層構造の光起電力装置を製造した。得られた光起電力
装置の初期効率は１、安定化効率は０．７６（低下率：
３％）、透明電極と金属電極との間の絶縁抵抗は５ｋ
Ω、太陽電池形状因子は０．５６であった。この光起電
力装置は安定化効率が低く、性能が劣るものである。[0042] (Comparative Example 1) Normal plasma defect density obtained by a CVD method using i Sohi Si film of 5 × 10 16 atoms / cm 3, 450 nm the thickness of the semiconductor film, a metal electrode A photovoltaic device having a laminated structure similar to that of Example 1 was manufactured with the film thickness set to 420 nm. The obtained photovoltaic device has an initial efficiency of 1 and a stabilization efficiency of 0.76 (decrease rate:
3%), insulation resistance between transparent electrode and metal electrode is 5k
Ω and the form factor of the solar cell were 0.56. This photovoltaic device has low stabilization efficiency and poor performance.
【００４３】（実施例３）図３に示す工程に従って、ガ
ラス基板上に実施例１と同様の特性を有する複数の単位
セルからなる集積型光起電力装置を製造した。ここで、
ｉ層非晶質シリコン膜の欠陥密度は５×１０15 個／ｃ
ｍ3、半導体膜厚は３４０ｎｍ、金属電極膜の膜厚は２
５０ｎｍとした。また、金属電極膜のスクライブには、
ガラス基板側からレーザ波長：１０６４ｎｍ、ビーム
径：８０μｍ、レーザパワー密度：７×１０3 Ｗ／ｃｍ
2、レーザパルス幅：６０ｎｓのＹＡＧレーザビームを
使用した。 得られた光起電力装置の規格化初期効率は
１、安定化効率は０．８８、透明電極と金属電極との間
の絶縁抵抗は１０ｋΩ以上、太陽電池形状因子は０．６
５以上であった。Example 3 According to the process shown in FIG. 3, an integrated photovoltaic device comprising a plurality of unit cells having the same characteristics as in Example 1 on a glass substrate was manufactured. here,
The defect density of the i-layer amorphous silicon film is 5 × 10 15 defects / c
m 3 , semiconductor film thickness is 340 nm, metal electrode film thickness is 2
It was 50 nm. In addition, for scribing the metal electrode film,
Laser wavelength: 1064 nm, beam diameter: 80 μm, laser power density: 7 × 10 3 W / cm from the glass substrate side
2. A YAG laser beam having a laser pulse width of 60 ns was used. The standardized initial efficiency of the obtained photovoltaic device is 1, the stabilization efficiency is 0.88, the insulation resistance between the transparent electrode and the metal electrode is 10 kΩ or more, and the solar cell form factor is 0.6.
It was 5 or more.
【００４４】[0044]
【発明の効果】以上詳細に説明したように、本発明の光
起電力装置は高い光起電力変換効率を有し、光劣化によ
る効率低下も少なく、透明電極膜と金属電極間の絶縁抵
抗が高いので高出力の電力が得られる利点がある。ま
た、ｉ層非晶質シリコン膜の膜厚が従来より薄くなって
いるので成膜時間が短縮でき、生産性が向上するので発
電コストを引き下げることが可能になる。また本発明の
光起電力装置の製造方法によれば、ｉ層非晶質シリコン
膜の欠陥密度を低減することができるので、ｉ層非晶質
シリコン膜の膜厚を薄くしても高い変換効率が達成でき
る。半導体膜の膜厚を薄いので成膜時間が短縮でき、生
産性が向上するので発電コストを引き下げることが可能
になる。さらに、本発明の光起電力装置の製造方法によ
れば、半導体膜の膜厚が薄いにもかかわらず、金属電極
膜を少ないエネルギーでバリを発生させることなく綺麗
に切断できるので、透明電極膜と金属電極間の絶縁抵抗
が高くてで高出力の電力が得られる集積型光起電力装置
が得られる利点がある。このように本発明は太陽電池の
コストダウンと大量普及にとって極めて有用である。As described in detail above, the photovoltaic device of the present invention has a high photovoltaic conversion efficiency, a small decrease in efficiency due to photodegradation, and a low insulation resistance between the transparent electrode film and the metal electrode. Since it is high, there is an advantage that high output power can be obtained. Further, since the film thickness of the i-layer amorphous silicon film is smaller than before, the film formation time can be shortened, and the productivity is improved, so that the power generation cost can be reduced. Further, according to the method for manufacturing a photovoltaic device of the present invention, since the defect density of the i-layer amorphous silicon film can be reduced, high conversion can be achieved even if the thickness of the i-layer amorphous silicon film is reduced. Efficiency can be achieved. Since the thickness of the semiconductor film is small, the deposition time can be shortened, and the productivity is improved, so that the power generation cost can be reduced. Furthermore, according to the method for manufacturing a photovoltaic device of the present invention, the metal electrode film can be cut neatly without generating burrs with little energy, despite the thin film thickness of the semiconductor film. There is an advantage that an integrated photovoltaic device that can obtain high output power with high insulation resistance between the metal electrode and the metal electrode can be obtained. As described above, the present invention is extremely useful for cost reduction and mass diffusion of solar cells.
【図１】非晶質シリコン光起電力装置の単位セルの断面
構造を示す図である。FIG. 1 is a diagram showing a sectional structure of a unit cell of an amorphous silicon photovoltaic device.
【図２】集積型非晶質シリコン光起電力装置の単位セル
の断面構造を示す図である。FIG. 2 is a diagram showing a cross-sectional structure of a unit cell of the integrated amorphous silicon photovoltaic device.
【図３】集積型非晶質シリコン光起電力装置の製造工程
を示す断面工程図である。FIG. 3 is a sectional process view showing a manufacturing process of the integrated amorphous silicon photovoltaic device.
【図４】従来の光起電力装置の非晶質シリコン半導体膜
の膜厚と規格化効率の関係を示す図である。FIG. 4 is a diagram showing the relationship between the thickness of an amorphous silicon semiconductor film and the standardization efficiency of a conventional photovoltaic device.
【図５】本発明の光起電力装置の非晶質シリコン半導体
膜の膜厚と規格化効率の関係を示す図である。FIG. 5 is a diagram showing the relationship between the thickness of the amorphous silicon semiconductor film and the standardization efficiency of the photovoltaic device of the present invention.
【図６】本発明の光起電力装置の非晶質シリコン半導体
膜の膜厚と規格化効率の関係の他の例を示す図である。FIG. 6 is a diagram showing another example of the relationship between the thickness of the amorphous silicon semiconductor film and the standardization efficiency of the photovoltaic device of the present invention.
【図７】半導体膜の膜厚と第２電極膜の膜厚との関係を
示す図である。FIG. 7 is a diagram showing the relationship between the thickness of a semiconductor film and the thickness of a second electrode film.
【図８】より好ましい半導体膜の膜厚と第２電極膜の膜
厚との関係を示す図である。FIG. 8 is a diagram showing a more preferable relationship between the thickness of the semiconductor film and the thickness of the second electrode film.
１，１１・・・・・ガラス基板、２，１２・・・・・透明電極膜、
３・・・・・ｐ層非晶質シリコン膜、４・・・・・ｉ層非晶質シリ
コン膜、５・・・・・ｎ層非晶質シリコン膜、６，１６・・・・・
半導体膜、７・・・・・金属電極膜、１０・・・・・単位セル、１
５・・・・・コンタクト部、１７・・・・・裏面電極膜、１８・・・・
・開溝、１９・・・・・コンタクト部開口、２０・・・・・開口部1,11 ... a glass substrate, 2,12 a transparent electrode film,
3... P-layer amorphous silicon film, 4... I-layer amorphous silicon film, 5... N-layer amorphous silicon film, 6, 16.
Semiconductor film, 7... Metal electrode film, 10... Unit cell, 1
5 Contact part, 17 Back electrode film, 18
.Grooves, 19... Contact opening, 20... Opening
───────────────────────────────────────────────────── フロントページの続き (72)発明者 竹内 良昭 長崎県長崎市深堀町五丁目717番１号 三 菱重工業株式会社長崎研究所内 (72)発明者 村田 正義 長崎県長崎市深堀町五丁目717番１号 長 菱エンジニアリング株式会社内 Ｆターム(参考） 5F051 AA05 BA14 CA03 CA15 DA04 EA02 EA11 EA16 FA02 GA03 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiaki Takeuchi 5-717-1 Fukahori-cho, Nagasaki-shi, Nagasaki Sanishi Heavy Industries Co., Ltd. Nagasaki Research Laboratory (72) Inventor Masayoshi Murata 5-717, Fukahori-cho, Nagasaki-shi, Nagasaki No. 1 Choshi Engineering Co., Ltd. F-term (reference) 5F051 AA05 BA14 CA03 CA15 DA04 EA02 EA11 EA16 FA02 GA03
Claims (8)
合構造の非晶質シリコンからなる半導体膜、金属電極膜
を順次積層して構成された光起電力装置であって、該半
導体膜の膜厚が２２０〜４００ｎｍであって、かつｉ層
非晶質シリコン膜の欠陥密度が５×１０15個／cm3 以下
であることを特徴とする光起電力装置。1. A photovoltaic device comprising a transparent electrode substrate, a semiconductor film made of amorphous silicon having a pin junction structure, and a metal electrode film sequentially laminated on a transparent insulating substrate. A photovoltaic device having a thickness of 220 to 400 nm and an i-layer amorphous silicon film having a defect density of 5 × 10 15 / cm 3 or less.
極膜の膜厚（ｙ）との関係が、半導体膜の膜厚を横軸
（ｘ軸）に金属電極膜の膜厚を縦軸（ｙ軸）に取った座
標軸において、点（ｘ、ｙ）がそれぞれＡ（２２０，２
００）、Ｂ（４００，２００）、Ｃ（４００，４０
０）、Ｄ（３４０，４００）であるＡＢＣＤ各点を結ん
だ範囲内にあることを特徴とする請求項１に記載の光起
電力装置。2. The relationship between the thickness (x) of the semiconductor film and the thickness (y) of the metal electrode film is such that the thickness of the metal electrode film is represented by the thickness of the semiconductor film on the horizontal axis (x-axis). On the coordinate axis on the vertical axis (y-axis), the point (x, y) is A (220, 2), respectively.
00), B (400, 200), C (400, 40)
2. The photovoltaic device according to claim 1, wherein the photovoltaic device is within a range connecting the ABCD points that are 0) and D (340, 400). 3.
ｍであって、かつ半導体膜の欠陥密度が１×１０15個／
cm3 以下であることを特徴とする請求項１に記載の光起
電力装置。3. The semiconductor film has a thickness of 280 to 380 n.
m and the defect density of the semiconductor film is 1 × 10 15 defects /
The photovoltaic device according to claim 1, wherein the photovoltaic device has a size of not more than cm 3 .
極膜の膜厚（ｙ）との関係が、半導体膜の膜厚を横軸
（ｘ軸）に金属電極膜の膜厚を縦軸（ｙ軸）に取った座
標軸において、点（ｘ、ｙ）がそれぞれＥ（２８０，２
００）、Ｆ（３８０，２００）、Ｇ（３８０，４０
０）、Ｄ（３４０，４００）、Ｈ（２８０，３００）で
あるＥＦＧＤＨ各点を結んだ範囲内にあることを特徴と
する請求項３に記載の光起電力装置。4. The relationship between the film thickness (x) of the semiconductor film and the film thickness (y) of the metal electrode film is such that the film thickness of the semiconductor film is represented by the horizontal axis (x-axis). On the coordinate axis on the vertical axis (y-axis), the point (x, y) is E (280, 2), respectively.
00), F (380, 200), G (380, 40
4. The photovoltaic device according to claim 3, wherein the photovoltaic device is within a range connecting the EFGDH points of 0), D (340, 400), and H (280, 300). 5.
の光起電力装置の単位セルを複数個直列に接続したこと
を特徴とする集積型光起電力装置。5. An integrated photovoltaic device, wherein a plurality of unit cells of the photovoltaic device according to claim 1 are connected in series.
と、この透明電極膜上にｐ層、ｉ層、ｎ層からなる非晶
質シリコン膜を順次形成する工程と、このｎ層非晶質シ
リコン膜上に金属電極膜を形成する工程とを具備した光
起電力装置の製造方法であって、前記ｉ層非晶質シリコ
ン膜を形成するに際して、シランガス（ＳｉＨ4 ）を使
用して基板近傍に金属メッシュを配置し、該金属メッシ
ュを加熱してプラズマＣＶＤ法により該ｉ層非晶質シリ
コン膜の欠陥密度が５×１０ 15個／cm3 以下であるｉ層
非晶質シリコン膜を形成することを特徴とする光起電力
装置の製造方法。6. A step of forming a transparent electrode film on a transparent substrate
And an amorphous layer comprising a p-layer, an i-layer, and an n-layer on the transparent electrode film.
A step of sequentially forming a porous silicon film;
Forming a metal electrode film on the recon film.
A method for manufacturing an electromotive force device, wherein the i-layer amorphous silicon
Silane gas (SiHFour )use
A metal mesh near the substrate using the metal mesh.
The i-layer amorphous silicon is heated by a plasma CVD method.
The defect density of the concrete film is 5 × 10 FifteenPieces / cmThree I-layer that is
Photovoltaic power characterized by forming an amorphous silicon film
Device manufacturing method.
該透明電極膜にレーザビームを照射して切断して開溝を
形成し、次いで該開溝を含む透明電極膜上にｐ層、ｉ
層、ｎ層からなる非晶質シリコン膜を順次形成した後、
非晶質シリコン膜にレーザービームを照射してコンタク
ト用開口を形成し、続いて該コンタクト用開口部及び非
晶質シリコン膜上に金属電極膜を形成し、しかる後に前
記透明基板側からパルス幅が６０ｎｓ以下のレーザビー
ムを照射して前記非晶質シリコン膜と金属電極膜を切断
して開口部を形成し、複数の領域に分割された光起電力
装置の単位セルが前記透明基板上で電気的に接続されて
なる集積型光起電力装置の製造方法。7. After forming a transparent electrode film on a transparent substrate,
The transparent electrode film is irradiated with a laser beam and cut to form a groove, and then a p-layer and an i-layer are formed on the transparent electrode film including the groove.
Layer and an n-layer amorphous silicon film are sequentially formed,
The amorphous silicon film is irradiated with a laser beam to form a contact opening, a metal electrode film is formed on the contact opening and the amorphous silicon film, and then a pulse width is applied from the transparent substrate side. Is irradiated with a laser beam of 60 ns or less to cut the amorphous silicon film and the metal electrode film to form an opening, and a unit cell of the photovoltaic device divided into a plurality of regions is formed on the transparent substrate. A method for manufacturing an integrated photovoltaic device electrically connected.
ｍであり、欠陥密度が５×１０15個／cm3 以下であっ
て、かつ金属電極膜の膜厚（ｙ）が、半導体膜の膜厚を
横軸（ｘ軸）に金属電極膜の膜厚を縦軸（ｙ軸）に取っ
た座標軸において、点（ｘ、ｙ）がそれぞれＡ（２２
０，２００）、Ｂ（４００，２００）、Ｃ（４００，４
００）、Ｄ（３４０，４００）であるＡＢＣＤ各点を結
んだ範囲内にあることを特徴とする請求項７に記載の集
積型光起電力装置の製造方法。8. The semiconductor film has a thickness of 220 to 400 n.
m, the defect density is 5 × 10 15 defects / cm 3 or less, and the thickness (y) of the metal electrode film is expressed by the thickness of the metal electrode film on the horizontal axis (x-axis) of the thickness of the semiconductor film. On a coordinate axis where the thickness is taken on the vertical axis (y axis), the point (x, y) is A (22).
0, 200), B (400, 200), C (400, 4)
The method for manufacturing an integrated photovoltaic device according to claim 7, wherein the points are within a range connecting the ABCD points which are (00) and D (340, 400).
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009177210A (en) * | 2009-05-11 | 2009-08-06 | Mitsubishi Heavy Ind Ltd | Manufacturing method of thin-film silicon lamination type solar cell |
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|---|---|---|---|---|
| JP2009177210A (en) * | 2009-05-11 | 2009-08-06 | Mitsubishi Heavy Ind Ltd | Manufacturing method of thin-film silicon lamination type solar cell |
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