JP3690772B2 - Photovoltaic element forming apparatus and forming method - Google Patents

Description

【００７４】
（比較例１）
本例では、真空容器１００内のカソード電極６０３及び真空容器６０２内のカソード電極６０４の構造を、図１０に示した平行平板型カソード電極構造とした点が実施例１と異なる。その際、カソード構造は、次のような寸法および配置とした。
【００７５】
▲１▼カソード電極のサイズは、幅５０ｃｍ×長さ１３０ｃｍとした。
▲２▼導電性帯状部材を含む接地されたアノード面積全体に対するカソード面積の比率は０．６倍とした。
▲３▼材料ガスはカソード電極上の放電空間を帯状部材の移動方向に流した。
【００７６】
また、各層の作製条件は表２に示した数値に設定した。
【００７７】
他の点は実施例１と同様とし、シングル型光起電力素子（素子−比１）を形成した。
【００７８】
【表２】

【００７９】
実施例１（素子−実１）および比較例１（素子−比１）で作製した光起電力素子の変換効率、特性均一性および歩留の評価を行った。
【００８０】
電流電圧特性は、帯状部材１０ｍおきに幅方向中央部、端部（端から５ｃｍ）から５ｃｍ角の面積で切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、光電変換効率を測定し、評価した。歩留は、切り出した５ｃｍ角素子の暗状態でのシャント抵抗を測定し、抵抗値が１×１０³Ω・ｃｍ²以上のものを良品としてカウントし、全数中の比率を百分率で表し、評価した。
【００８１】
表３に、上記の評価結果を示した。表３に示した実施例１（素子−実１）の各値は、比較例１（素子−比１）の各特性の平均値を１．００として規格化した数値である。
【００８２】
【表３】

【００８３】
表３から、（素子−実１）は（素子−比１）に比べて全体的に各特性が向上しており、特に開放電圧の向上が認められた結果、変換効率が１．０５倍に向上することが分かった。
【００８４】
表３に示すように、比較例１（素子−比１）の光起電力素子に対して、実施例１（素子−実１）の光起電力素子は、変換効率において優れており、本発明の作製方法により作製した光起電力素子が、優れた特性を有することが判明し、本発明の効果が実証された。
【００８５】
帯状部材幅方向の特性均一性は、実施例１（素子−実１）、比較例１（素子−比１）で作製した帯状部材上の光起電力素子を、１０ｍおきに幅方向中央および端部（端から５ｃｍ）で５ｃｍ角の面積で切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、光電変換効率を測定して、その光電変換効率の幅方向分布を評価した。幅方向中央部と端部の各特性値の平均値のばらつき（％表示）を表４に示した。
【００８６】
【表４】

【００８７】
表４から、比較例１（素子−比１）の光起電力素子に対して、実施例１（素子−実１）の光起電力素子は、特性均一性においても優れており、本発明の作製方法により作製したシングル型光起電力素子が、優れた特性を有することが判明し、本発明の効果が実証された。
【００８８】
（実施例２）
本例では、ｉ型層作製用真空容器１００内のカソード電極は実施例１と同様として、材料ガスの導入口と排気口の配置は図６に、材料ガスの導入方法及び制御方法は図９に示した構成に代えて、組成制御されたｉ型ａ−ＳｉＧｅ₄：Ｈ堆積膜をＳＵＳ４３０ＢＡからなる帯状部材上（長さ１００ｍ）に作製した。
【００８９】
以下の説明において、しきり状電極の間の放電空間を帯状部材の搬送方向上手側から(1),(2),......,(16),(17)と呼称する。また、しきり状電極と帯状部材の間隔（図１におけるｌ１）は０．５ｃｍとした。
【００９０】
しきり状電極間に供給される材料ガスとしてはＳｉＨ₄，ＧｅＨ₄，Ｈ₂ガスを用いた。ＧｅＨ₄ガスは、中央部に位置するしきり状電極間（放電空間）の(11)から両端に向かって供給量を減らし、両端(1),(17)では零となるように設定した。一方、ＳｉＨ₄ガスは、両端に位置するしきり状電極間（放電空間）の(1)及び(17)から中央部の(11)に向かって供給量を減らすように設定した。また、Ｈ₂は各フィン間で均等に供給した。
【００９１】
表５には、ｉ型層の作製条件を示した。
【００９２】
【表５】

【００９３】
堆積膜の形成された帯状部材の幅方向中央部、端部の一部を１０ｍごとにそれぞれ切り出し、ＳＩＭＳを用いて堆積膜の厚さ（表面からの深さ）方向の組成分析を行った。その結果、図１６において実線で示したデプスプロファイルが得られ、ほぼ図１７に示すようなバンドプロファイルが形成されていることが分かった。
【００９４】
（比較例２）
本例では、ｉ型層作製用真空容器１００内のカソード電極構造を、図１０で示した平行平板のカソード電極構造（従来型：この場合、導電性帯状部材を含む接地されたアノード面積全体に対するカソード面積の比率は０．６倍）として、帯状部材を移動させずに静止固定の状態で、組成制御されたｉ型ａ−ＳｉＧｅ₄：Ｈ堆積膜をＳＵＳ４３０ＢＡ帯状部材上に作製した。
【００９５】
ｉ型層の組成制御は表６に示すように成膜時間の経過に対応してＳｉＨ₄とＧｅＨ₄の混合比をなめらかに変化させる方法で行った。
【００９６】
【表６】

【００９７】
堆積膜の形成された帯状部材を任意の位置で切り出し、実施例２と同様の組成分析を行ったところ、図１６において破線で示すなめらかなデプスプロファイルが得られ、ほぼ図１７に示す実施例２と同様のバンドプロファイルが形成されていることが分かった。
【００９８】
従って、本発明の装置及び方法により堆積膜の厚さ方向の組成を制御できることが明らかとなった。
【００９９】
また、本発明の装置及び方法により堆積膜の厚さ方向の組成を帯状部材の幅方向で均一に形成できることも確認された。
【０１００】
さらに、実施例２で作製した堆積膜のデプスプロファイルは、比較例２で作製した堆積膜と同様に滑らかな変化を示しており、実施例２による堆積膜は滑らかな変化のバンドプロファイルが形成されている。すなわち、本発明の装置及び方法によりａ−ＳｉＧｅ：Ｈグレーデッドバンドギャップ構造などの堆積膜の厚さ方向の組成制御をなめらかに制御できることが分かった。
【０１０１】
（実施例３）
本例では、実施例２に示したａ−ＳｉＧｅ：Ｈグレーデッドバンドギャップｉ型層を採用し、図１２に示したシングル型光起電力素子を、表７に示す作製条件で作製した。本例で作製した光起電力素子は、（素子−実３）と呼称する。
【０１０２】
他の点は実施例１と同様とした。
【０１０３】
【表７】

【０１０４】
（比較例３）
本例では、ａ−ＳｉＧｅ：Ｈグレーデッドバンドギャップｉ型層を、ａ−ＳｉＧｅ：Ｈフラットバンドギャップｉ型層とこれを挟むａ−Ｓｉ：Ｈフラットバンドギャップｉ型（第１，２の）バッファ層の３層構成として、図１４に示したシングル型光起電力素子を、表８に示す作製条件で作製した。本例で作製した光起電力素子は、（素子−比３）と呼称する。
【０１０５】
上記ｉ型層の作製装置としては、図１０に示した平行平板型カソード電極構造（導電性帯状部材を含む接地されたアノード面積全体に対するカソード面積の比率は０．６倍）をもつ上記３層成膜用真空容器を配置した図１１と同様の装置を用いた。
【０１０６】
他の点は実施例１と同様とした。
【０１０７】
【表８】

【０１０８】
実施例３（素子−実３）および比較例３（素子−比３）で作製した光起電力素子の変換効率、特性均一性および歩留の評価を行った。
【０１０９】
電流電圧特性は、帯状部材１０ｍおきに幅方向中央部、端部（端から５ｃｍ）から５ｃｍ角の面積で切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、光電変換効率を測定し、評価した。歩留は、実施例３（素子−実３）、比較例１（素子−比３）で作製した帯状部材上の光起電力素子を、１０ｍおきに５ｃｍ角の面積で切出し、その暗状態でのシャント抵抗を測定し、抵抗値が１×１０³Ω・ｃｍ²以上のものを良品としてカウントし、全数中の比率を百分率で表し、評価した。
【０１１０】
表９に、上記の評価結果を示した。表９に示した実施例３（素子−実３）の各値は、比較例３（素子−比３）の各特性の平均値を１．００として規格化した数値である。
【０１１１】
【表９】

表９から、（素子−実３）は（素子−比３）に比べて全体的に各特性が向上しており、特に開放電圧の向上が認められた結果、変換効率が１．０５倍に向上することが分かった。
【０１１２】
表９に示すように、比較例３（素子−比３）の光起電力素子に対して、実施例３（素子−実３）の光起電力素子は、変換効率において優れており、本発明の作製方法により作製した光起電力素子が、優れた特性を有することが判明し、本発明の効果が実証された。
【０１１３】
帯状部材幅方向の特性均一性は、実施例３（素子−実３）、比較例３（素子−比３）で作製した帯状部材上の光起電力素子を、１０ｍおきに幅方向中央および端部（端から５ｃｍ）で５ｃｍ角の面積で切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、光電変換効率を測定して、その光電変換効率の幅方向分布を評価した。幅方向中央部と端部の各特性値の平均値のばらつき（％表示）を表１０に示した。
【０１１４】
【表１０】

【０１１５】
表１０から、比較例３（素子−比３）の光起電力素子に対して、実施例３（素子−実３）の光起電力素子は、特性均一性においても優れており、本発明の作製方法により作製したシングルセル型光起電力素子が、優れた特性を有することが判明し、本発明の効果が実証された。
【０１１６】
（実施例４）
本例では、図１の形成容器を、図１１に示すようなロール・ツー・ロール（Roll to Roll）方式の連続プラズマＣＶＤ装置におけるｉ型層形成容器として用い、図１３に示したトリプルセル型光起電力素子を作製した。その際、図１の形成容器におけるカソード構造は、次のような寸法および配置とした。
【０１１７】
▲１▼帯状部材とカソード電極の一部であるしきり状電極との最近接距離（図１おけるｌ１）は０．５ｃｍとした。
▲２▼複数設置されたしきり状電極同士の間隔（図１おけるｌ２）は５ｃｍとした。
▲３▼導電性帯状部材を含む接地されたアノード面積全体に対するカソード面積の比率は３．０倍とした。
【０１１８】
図１１に示すようなロール・ツー・ロール（Roll to Roll）方式を採用した連続プラズマＣＶＤ装置（不図示）とは、図１１に示した、第１の導電型層作製用真空容器６０１、ｉ型層作製用真空容器１００、第２の導電型層作製用真空容器６０２をガスゲートを介して接続した装置をワンセットとし、これをさらに２セット増設して、計３セット繰り返して直列に配置した構成の装置である。そして、全てのｉ型層形成容器に、上述した形成容器を設置した。
【０１１９】
上記構成からなる装置を用いて、図１３に示したトリプルセル型光起電力素子を、表１１に示す作製条件で作製した。図１３において、５００１はＳＵＳ基板、５００２はＡｇ薄膜、５００３はＺｎＯ薄膜、５００４は第１の導電型層、５００５は第１のｉ型層、５００６は第２の導電型層、５００７は第１の導電型層、５００８は第２のｉ型層、５００９は第２の導電型層、５０１０は第１の導電型層、５０１１は第３のｉ型層、５０１２は第２の導電型層、５０１３はＩＴＯ、５０１４は集電電極である。
【０１２０】
上記各層は連続的に作製し、トリプルセル型光起電力素子（素子−実４）を形成した。表１１には、各層の作製条件を示した。
【０１２１】
【表１１】

【０１２２】
（比較例４）
本例では、ａ−ＳｉＧｅ：Ｈグレーデッドバンドギャップｉ型層を、ａ−ＳｉＧｅ：Ｈフラットバンドギャップｉ型層とこれを挟むａ−Ｓｉ：Ｈフラットバンドギャップｉ型（第１，２の）バッファ層の３層構成として、図１５に示したトリプルセル型光起電力素子を形成した。表１２には、各層の作製条件を示した。本例で作製した光起電力素子は、（素子−比４）と呼称する。
【０１２３】
上記ｉ型層の作製装置としては、図１０に示した平行平板型カソード電極構造（導電性帯状部材を含む接地されたアノード面積全体に対するカソード面積の比率は０．６倍）をもつ上記３層成膜用真空容器を配置した実施例４で使用した装置を用いた。
【０１２４】
他の点は実施例４と同様とした。
【０１２５】
【表１２】

【０１２６】
実施例４（素子−実４）および比較例４（素子−比４）で作製した光起電力素子の変換効率、特性均一性および歩留の評価を行った。
【０１２７】
電流電圧特性は、帯状部材１０ｍおきに幅方向中央部、端部（端から５ｃｍ）から５ｃｍ角の面積で切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、光電変換効率を測定し、評価した。歩留は、実施例３（素子−実３）、比較例１（素子−比３）で作製した帯状部材上の光起電力素子を、１０ｍおきに５ｃｍ角の面積で切出し、その暗状態でのシャント抵抗を測定し、抵抗値が１×１０³Ω・ｃｍ²以上のものを良品としてカウントし、全数中の比率を百分率で表し、評価した。
【０１２８】
表１３に、上記の評価結果を示した。表１３に示した実施例４（素子−実４）の各値は、比較例４（素子−比４）の各特性の平均値を１．００として規格化した数値である。
【０１２９】
【表１３】

【０１３０】
表１３から、（素子−実４）は（素子−比４）に比べて全体的に各特性が向上しており、特に開放電圧の向上が認められた結果、変換効率が１．０６倍に向上することが分かった。
【０１３１】
表１３に示すように、比較例４（素子−比４）の光起電力素子に対して、実施例４（素子−実４）の光起電力素子は、変換効率において優れており、本発明の作製方法により作製した光起電力素子が、優れた特性を有することが判明し、本発明の効果が実証された。
【０１３２】
帯状部材幅方向の特性均一性は、実施例４（素子−実４）、比較例４（素子−比４）で作製した帯状部材上の光起電力素子を、１０ｍおきに幅方向中央および端部（端から５ｃｍ）で５ｃｍ角の面積で切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、光電変換効率を測定して、その光電変換効率の幅方向分布を評価した。幅方向中央部と端部の各特性値の平均値のばらつき（％表示）を表１４に示した。
【０１３３】
【表１４】

【０１３４】
表１４から、比較例４（素子−比４）の光起電力素子に対して、実施例４（素子−実４）の光起電力素子は、特性均一性においても優れており、本発明の作製方法により作製したトリプルセル型光起電力素子が、優れた特性を有することが判明し、本発明の効果が実証された。
【０１３５】
また、実施例３と比較例３との比較、および実施例４と比較例４との比較により、本発明に係る装置は、装置のコンパクト化が図れるとともに、付帯設備の軽量化や材料ガスの消費量削減に有効であることが分かった。
【０１３６】
【発明の効果】
本発明によれば、連続的に移動する導電性の帯状部材上に、非単結晶からなる第１の導電型半導体層、ｉ型半導体層及び第２の導電型半導体層を順次積層した構造体を１組以上有する光起電力素子の形成において、
前記ｉ型半導体層の形成に用いる放電容器として、
帯状部材の移動方向に垂直に並んだしきり状カソード電極を備えた放電容器を用い、放電時のカソード電位（自己バイアス）を正電位とし、材料ガスを隣接するしきり状電極の間に導入し、しきり状電極に沿って基板搬送方向と直角（基板幅）方向に流すことにより、また、その材料ガスの組成比（混合比）を基板搬送方向に沿って変化させる事で、前記ｉ型半導体層の膜組成をその膜厚方向に精密に組成制御することができる。
【０１３７】
また、上記ｉ型半導体層を採用することにより、大面積にわたって、高い光電変換効率と高品質で優れた均一性とを有し、より再現性高く欠陥の少ない光起電力素子を大量に安定して作製することができる。
【０１３８】
さらに、形成装置の小型化が図れるとともに、材料ガスの使用量を削減することも可能となる。
【図面の簡単な説明】
【図１】本発明の形成装置を構成する放電容器内の構造を示した模式的な断面図である。
【図２】図１に示したカソード電極の一例を示す模式的な鳥瞰図である。
【図３】材料ガスの導入口及び排気口を設ける位置と材料ガスの流れとを示したカソード電極の一例を示す模式的な平面図である。
【図４】材料ガスの導入口及び排気口を設ける位置と材料ガスの流れとを示したカソード電極の他の一例を示す模式的な平面図である。
【図５】材料ガスの導入口及び排気口を設ける位置と材料ガスの流れとを示したカソード電極の他の一例を示す模式的な平面図である。
【図６】材料ガスの導入口及び排気口を設ける位置と材料ガスの流れとを示したカソード電極の他の一例を示す模式的な平面図である。
【図７】材料ガスの導入口及び排気口を設ける位置と材料ガスの流れとを示したカソード電極の他の一例を示す模式的な平面図である。
【図８】放電空間に導入する材料ガス供給方法の一例を示した模式図である。
【図９】放電空間に導入する材料ガス供給方法の他の一例を示した模式図である。
【図１０】従来のカソード電極を有する放電容器の一例を示す模式的な断面図である。
【図１１】本発明に係る光起電力素子の形成装置の一例を示した模式的な断面図である。
【図１２】本発明に係る装置及び方法により形成したシングルセル型光起電力素子の模式的な断面図である。
【図１３】本発明に係る装置及び方法により形成したトリプルセル型光起電力素子の模式的な断面図である。
【図１４】比較例３で用いた従来のシングルセル型光起電力素子の模式的な断面図である。
【図１５】比較例４で用いた従来のトリプルセル型光起電力素子の模式的な断面図である。
【図１６】実施例２及び比較例２で作製した堆積膜のＳＩＭＳによる組成分析のデプスプロファイルである。
【図１７】実施例２及び比較例２で作製した堆積膜のバンドプロファイルである。
【符号の説明】
１００ 真空容器、
１０１ 帯状部材、
１０３ａ、１０３ｂ、１０３ｃ 加熱ヒーター、
１０４ａ、１０４ｂ、１０４ｃ ガス導入管、
１０７ カソード電極、
１２４ｎ、１２４、１２４ｐ ランプヒーター、
１２９ｎ、１２９、１２９ｐ、１３０ ガスゲート、
１３１ｎ、１３１、１３１ｐ、１３２ ガスゲート導入管、
３０１、３０２ 真空容器、
３０３、３０４ ボビン、
３０５、３０６ アイドリングローラ、
３０７、３０８ コンダクタンスバルブ、
３１０、３１１ 排気管、
３１４、３１５ 圧力計、
５１３ 排気管、
６０１、６０２ 真空容器、
６０３、６０４ カソード電極、
６０５、６０６ ガス導入管、
６０７、６０８ 排気管、
１０００ 導電性帯状部材、
１００１ 真空容器、
１００２ カソード電極、
１００３ しきり状電極、
１００４ 接地（アノード）電極、
１００５ ランプヒーター、
１００６ 排気口、
１００７ ガス導入管、
１００８ ガスゲート、
１００９ 絶縁ガイシ、
１０１０ 放電空間、
１０１１ マスフローコントローラー、
１０１２ ガスボンベ、
１０１３ ガス混合部、
２０００ 導電性帯状部材、
２００１ 真空容器、
２００２ カソード電極、
２００４ 接地（アノード）電極、
２００５ ランプヒーター、
２００６ 排気口、
２００７ ガス導入管、
２００８ ガスゲート
２００９ 絶縁ガイシ
２０１０ 放電空間
４００１ ＳＵＳ基板、
４００２ Ａｇ薄膜、
４００３ ＺｎＯ薄膜、
４００４ 第１の導電型層、
４００５ ｉ型層、
４００６ 第２の導電型層、
４００７ ＩＴＯ、
４００８ 集電電極、
５００１ ＳＵＳ基板
５００２ Ａｇ薄膜、
５００３ ＺｎＯ薄膜、
５００４ 第１の導電型層、
５００５ 第１のｉ型層、
５００６ 第２の導電型層、
５００７ 第１の導電型層、
５００８ 第２のｉ型層、
５００９ 第２の導電型層、
５０１０ 第１の導電型層、
５０１１ 第３のｉ型層、
５０１２ 第２の導電型層、
５０１３ ＩＴＯ、
５０１４ 集電電極、
６００１ ＳＵＳ基板、
６００２ Ａｇ薄膜、
６００３ ＺｎＯ薄膜、
６００４ 第１の導電型層、
６００５ 第１のバッファ層、
６００６ ｉ型層、
６００７ 第２のバッファ層、
６００８ 第２の導電型層、
６００９ ＩＴＯ、
６０１０ 集電電極、
７００１ ＳＵＳ基板、
７００２ Ａｇ薄膜、
７００３ ＺｎＯ薄膜、
７００４ 第１の導電型層、
７００５ 第１のバッファ層、
７００６ 第１のｉ型層、
７００７ 第２のバッファ層、
７００８ 第２の導電型層、
７００９ 第１の導電型層、
７０１０ 第１のバッファ層、
７０１１ 第２のｉ型層、
７０１２ 第２のバッファ層、
７０１３ 第２の導電型層、
７０１４ 第１の導電型層、
７０１５ 第３のｉ型層、
７０１６ 第２の導電型層、
７０１７ ＩＴＯ、
７０１８ 集電電極。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photovoltaic device forming apparatus and method. More specifically, by forming the i-type semiconductor layer by controlling the composition ratio in the film thickness direction, a photovoltaic device having high photoelectric conversion efficiency and high quality and excellent uniformity over a large area. The present invention relates to an apparatus and method that can be formed. In particular, it is suitably used as an apparatus and method for forming a photovoltaic element by a roll-to-roll method for mass-producing photovoltaic elements such as solar cells using amorphous silicon or amorphous silicon alloy.
[0002]
[Prior art]
Photovoltaic elements, which are photoelectric conversion elements that convert sunlight into electrical energy, are widely applied as power sources for consumer use such as calculators and wristwatches. In the future, so-called fossil fuels such as oil and coal are used. It is attracting attention as a technology that can be put to practical use as an alternative power. A photovoltaic device is a technology that uses photovoltaic power generated at a pn junction of a semiconductor, and a semiconductor such as silicon absorbs sunlight to generate photocarriers of electrons and holes, and the photocarrier is converted into a pn junction. It drifts depending on the internal electric field and is taken out to the outside.
[0003]
Examples of the material constituting the semiconductor of such a photovoltaic element include single crystal silicon, polycrystalline silicon, and amorphous silicon.
[0004]
From the point of efficiency of converting light energy into electromotive force, it is desirable to use single crystal silicon. However, since crystalline silicon such as single crystal has an indirect optical edge, light absorption is small, and single crystal silicon The solar cell needs to have a thickness of at least 50 μm in order to absorb incident light. In addition, the band gap of single crystal silicon is about 1.1 eV, which is narrower than 1.5 eV, which is suitable for a solar cell, and thus has a drawback that a short wavelength component cannot be effectively used.
[0005]
On the other hand, when polycrystalline silicon is used instead of single crystal silicon, the production cost can be reduced. However, the problem of the indirect optical edge cannot be solved, and the thickness of the solar cell cannot be reduced. Furthermore, polycrystalline silicon has many problems to be solved because it has both grain boundaries and other problems.
[0006]
On the other hand, amorphous silicon formed by chemical vapor deposition (CVD) is promising from the viewpoint of increasing the area and reducing the cost. However, although this amorphous silicon solar cell has been widely spread as a small power source for consumer use, there are still problems in terms of high efficiency and stabilization as a power element.
[0007]
As a method for solving such a problem of amorphous silicon, there are the following reports.
[0008]
U.S. Pat. No. 2,949,498 describes that multiple cells are used to improve the efficiency of a photovoltaic cell. A pn junction crystal semiconductor was used for this multiple battery, but the idea is common to both amorphous and crystalline materials, and the solar spectrum is efficiently absorbed by photovoltaic elements of different band gaps. , Voc is increased to improve power generation efficiency.
[0009]
US Pat. No. 4,377,723 discloses an improved version of the above-described multiple battery, in which three elements are stacked using amorphous silicon having a pin junction and amorphous silicon germanium as photovoltaic elements. A so-called a-SiH / a-SiGe: H / a-SiGe: H triple cell solar cell that increases the overall Voc has been reported. In this solar cell, the amorphous silicon germanium is used for the second photovoltaic element layer, whereby the film thickness of the i layer of the second photovoltaic element can be reduced, and the photogenerated carriers can be blown. The characteristics of the solar cell are improved by the paying effect.
[0010]
However, the following problems have been pointed out when amorphous silicon germanium is used as the material constituting the semiconductor of the photovoltaic element.
[0011]
First, germanium acts as an impurity having characteristics with respect to amorphous silicon, and the photovoltaic characteristics of solar cells made of silicon, germanium, and hydrogen are deteriorated.
[0012]
Second, in order to improve the photovoltaic characteristics of the above-mentioned amorphous silicon germanium alloy (hereinafter abbreviated as amorphous SiGe alloy), defect states caused by introduction of germanium in the amorphous SiGe alloy by hydrogen are introduced. In addition to the compensation of the above, it is necessary to significantly improve the electronic state in the energy gap.
[0013]
As a countermeasure against this, Japanese Patent Publication No. 63-48197 discloses compensation of dangling bonds in an amorphous SiGe alloy using activated fluorine atoms in order to produce a high-quality amorphous SiGe alloy. And an amorphous SiGe alloy with a substantially reduced defect density is disclosed.
[0014]
On the other hand, as a method other than the essential improvement of the film quality described above, improvement of characteristics of a solar cell containing amorphous SiGe has been studied.
[0015]
As an example of this, a so-called buffer is disclosed in US Pat. No. 4,254,429, in which a bandwidth gradient is provided at the junction interface between a p-type semiconductor and / or an n-type semiconductor layer and an i-type semiconductor layer. The method using a layer is mentioned.
[0016]
As another method, there is disclosed a method of providing a so-called gradient layer that improves the characteristics by providing a composition distribution in the intrinsic layer by changing the composition ratio of silicon and germanium. For example, in U.S. Pat. No. 4,816,082, the band gap of the i layer in the portion in contact with the first valence-controlled semiconductor layer on the light incident side is widened and gradually toward the center. A method is disclosed in which the band gap is narrowed and further gradually widened toward the second valence-controlled semiconductor layer. According to this method, carriers generated by light can be efficiently separated by the action of an internal electric field, and the film characteristics are improved.
[0017]
As a method for continuously forming a semiconductor functional deposition film used for a photovoltaic element or the like on a substrate, an independent film formation chamber for forming various semiconductor layers is provided, and each of these film formation chambers is a gate valve. There is known a method in which various semiconductor layers are formed by sequentially connecting a substrate to each film forming chamber and being connected by a load lock method via a substrate.
[0018]
In particular, as a method for significantly improving mass productivity, US Pat. No. 4,400,409 discloses a continuous plasma CVD method employing a roll-to-roll method. According to this method, by using a long belt-like member as a substrate, while depositing and forming a conductive type semiconductor layer required in a plurality of glow discharge regions, the substrate is continuously conveyed in the longitudinal direction, It is described that an element having a semiconductor junction can be continuously formed.
[0019]
According to this method, it takes several hours to form a semiconductor layer on a strip-like substrate of several hundred meters, and the semiconductor layer is formed by maintaining and controlling a uniform and reproducible discharge state. There is a need to. Therefore, it is necessary to develop a method for continuously and yielding a high-quality and uniform semiconductor deposited film over the entire length of the long band-shaped substrate from the start to the end.
[0020]
For example, when a graded band gap thin film semiconductor layer of amorphous silicon germanium is used as the i-type semiconductor layer of the photovoltaic element, silane (SiH _Four ), Germanic (GeH _Four A semiconductor film having a desired conductivity type can be obtained by mixing raw material gases such as) and performing glow discharge decomposition. However, in order to form a high-quality amorphous silicon germanium thin film having a desired band gap, the dependence on the film formation conditions is very large in essence, and it is extremely difficult to slightly change (shift) the film formation conditions. Because of its sensitivity, if it deviates from the optimum formation conditions for some reason, the performance of photovoltaic elements such as fill factors tends to deteriorate.
[0021]
Further, in the conventional typical discharge vessel internal structure, the area of the entire grounded anode electrode including the substrate is often very large compared to the area of the cathode electrode. In such a cathode electrode, As a result of most of the high-frequency power input being consumed in the vicinity of the cathode electrode, the excitation and decomposition reaction of the material gas is active only in a limited portion in the vicinity of the cathode electrode. Even if a large amount of high frequency power is applied in the vicinity of the electrode, the high frequency power to the substrate, which is the anode electrode, is not sufficiently large and a high deposition rate as desired. Therefore, it is difficult to form a semiconductor thin film, and it is very difficult to obtain a good quality semiconductor thin film. .
[0022]
Furthermore, in a conventional typical discharge vessel structure, that is, a discharge vessel having a structure in which the area of the grounded anode electrode including the substrate is much larger than the area of the cathode electrode, a direct current (DC) power source or the like is used. A technique of applying a positive potential (bias) to the cathode electrode has also been performed. However, in such a system, as a result of using a secondary means such as a DC power source, a DC current flows in the plasma discharge. Therefore, if the DC voltage bias is increased, abnormal discharge such as sparks occurs. It was very difficult to suppress this and maintain a stable discharge. Therefore, it was unclear whether the effect of applying a DC voltage to the plasma discharge was effective. This is due to the fact that the DC voltage and DC current cannot be separated. That is, a means for effectively applying only a DC voltage to plasma discharge has been desired.
[0023]
In addition, the i-type semiconductor layer of the photovoltaic element is often set to a very thin thickness of several hundred to several thousand hundreds from the viewpoint of element characteristics. In some cases, the layer thickness uniformity, film adhesion, composition, property uniformity, and reproducibility not only affect the device properties, but also greatly affect the device yield.
[0024]
Therefore, in order to form a non-single crystal thin film that is spatially and temporally uniform and reproducible, a further improved discharge stability over a long period of time, a formation method with improved reproducibility and uniformity, and There is a need for a forming apparatus. In order to improve the throughput of the apparatus and reduce the cost, it is desired to develop a forming method and a forming apparatus that can realize a high deposition rate while maintaining the quality of the semiconductor thin film. Furthermore, the basic characteristics of the i-type semiconductor layer greatly affect the characteristics of the photovoltaic element electrically and optically. Particularly, in the laminated photovoltaic element, the optical forbidden band width and the Fermi level are precise. Since control is required, there is a need for a method and apparatus that can form a high-quality i-type semiconductor layer uniformly and continuously with high reproducibility.
[0025]
[Problems to be solved by the invention]
The present invention provides a photocatalyst having a high photoelectric conversion efficiency over a large area, high quality, excellent uniformity, excellent reproducibility, and few defects on a continuously moving strip member. An object of the present invention is to provide a forming method and a forming apparatus capable of manufacturing a large amount of power elements.
[0026]
[Means for Solving the Problems]
The present inventor has solved the above-mentioned problems in the prior art, and as a result of intensive studies to achieve the object of the present invention, has been completed.
[0027]
The apparatus for forming a photovoltaic device of the present invention includes a first conductive semiconductor layer, an i-type semiconductor layer, and a second conductive semiconductor made of non-single crystal on a conductive belt-like member that moves continuously. In a photovoltaic device forming apparatus having one or more structures in which layers are sequentially stacked,
The discharge vessel used for forming the i-type semiconductor layer has a discharge space of the whole anode electrode in which the surface area in the discharge space of a high-frequency power application electrode (hereinafter referred to as a cathode electrode) installed in the discharge space includes the surface area of the strip-shaped member. The surface potential of the cathode electrode when glow discharge occurs (hereinafter referred to as self-bias) can be maintained at a positive potential of +30 V or more with respect to the grounded anode electrode including the belt-shaped member, and A plurality of the fin-shaped cathode electrodes (hereinafter referred to as “threshold electrodes”) are provided in a plurality perpendicular to the conveying direction of the strip-shaped member, and the spacing between the respective thru-shaped electrodes is between the adjacent thru-shaped electrodes. The cathode structure having a sufficient interval for maintaining discharge in the substrate and the material gas used for forming the i-type semiconductor layer are adjacent to each other. Is introduced from the cathode electrode surface between Jo electrodes into each discharge space partitioned by the partition-like electrodes, the moving direction of the belt-shaped member along the partition-like electrodes Orthogonal And a mechanism for applying high frequency power to the cathode electrode to decompose the material gas by plasma discharge.
[0028]
The photovoltaic device forming apparatus according to the present invention may further include a gas supply for independently introducing the plurality of types of material gases into the discharge space when the plurality of types of material gases are introduced into the discharge space between the threshold electrodes. It is characterized by having means.
[0029]
The photovoltaic device forming apparatus of the present invention having the above-described configuration has the following operation.
[0030]
(1) The discharge vessel used for forming the i-type semiconductor layer has a surface area in the discharge space of a high-frequency power application electrode (hereinafter referred to as a cathode electrode) installed in the discharge space. The surface area in the discharge space is larger, and the potential of the cathode electrode when glow discharge occurs (hereinafter referred to as self-bias) can maintain a positive potential of +30 V or more with respect to the grounded anode electrode including the belt-shaped member, In addition, a plurality of fin-shaped cathode electrodes (hereinafter referred to as “threshold electrodes”) are provided in a plurality perpendicular to the transport direction of the strip-shaped member, and the spacing between the respective thru-shaped electrodes is adjacent to the above-described thru-shaped electrodes. A cathode structure with sufficient spacing to maintain a discharge between the two, which is a disadvantage in conventional devices. The excitation and decomposition reaction of the material gas is not promoted only in a limited portion in the vicinity of the cathode electrode, and the excitation and decomposition of the material gas described above is performed on the entire discharge space, that is, the anode electrode side including the band-shaped member. The reaction can be accelerated and a thin film can be efficiently deposited on the strip with a relatively high deposition rate. That is, the amount of high-frequency power input to the cathode is well adjusted, the input high-frequency power is more effectively utilized, the material gas introduced into the discharge space is efficiently excited, decomposed, and high-quality non- A single crystal semiconductor thin film can be formed on the strip-like member with a relatively high deposition rate with good reproducibility.
[0031]
(2) The material gas used for forming the i-type semiconductor layer is introduced into the discharge space between the threshold electrodes from between the adjacent threshold electrodes, and the moving direction of the strip member along the threshold electrodes is By supplying a mechanism for flowing in a perpendicular direction (width direction of the strip member) and applying high frequency power to the cathode electrode to decompose the material gas by plasma discharge, a plurality of members are provided along the transport direction of the strip member. Adjacent plasma spaces can be provided. As a result, the long film formation space (that is, the chamber length) necessary for forming the i-type graded bandgap semiconductor layer in the roll-to-roll method, which is a drawback in the prior art, can be greatly shortened. A forming device is obtained.
[0032]
(3) When a plurality of types of material gases are introduced into the discharge space between the threshold electrodes, gas supply means for guiding the plurality of types of material gases to the discharge space independently of each other is provided. A gas having an arbitrary composition ratio can be freely introduced along the transport direction. As a result, it is possible to form a deposited film whose composition is precisely controlled in the film thickness direction on the belt-shaped member.
[0033]
That is, by using the apparatus of the present invention, for example, a silicon germanium graded bandgap semiconductor film whose composition is precisely controlled in the film thickness direction is a more compact apparatus than before and the consumption of material gas is reduced. Can be formed. Here, the compact apparatus refers to an apparatus with a reduced number of chambers or an apparatus with a reduced chamber length.
[0034]
According to the method for forming a photovoltaic element of the present invention, a first conductive type semiconductor layer, an i type semiconductor layer, and a second conductive type semiconductor made of a non-single crystal are formed on a conductive belt-like member that moves continuously. In a method for forming a photovoltaic device having one or more sets of structures in which layers are sequentially stacked,
As a discharge vessel used for forming the i-type semiconductor layer, the surface area of the discharge space of a high-frequency power application electrode (hereinafter referred to as a cathode electrode) installed in the discharge space is the discharge space of the entire anode electrode including the surface area of the strip-shaped member. The cathode electrode potential (hereinafter referred to as self-bias) when glow discharge occurs is maintained at a positive potential of +30 V or more with respect to the grounded anode electrode including the belt-like member. In addition, a plurality of fin-shaped cathode electrodes (hereinafter referred to as “threshold electrodes”) are provided in a plurality perpendicular to the transport direction of the belt-like member, and the intervals between the respective threshold electrodes are adjacent to each other. Of a photovoltaic device with a discharge vessel having a cathode structure with sufficient spacing to cause and maintain a discharge between the electrode-like electrodes The apparatus is used to introduce a material gas used for forming the i-type semiconductor layer from the cathode electrode surface between adjacent threshold electrodes into each discharge space partitioned by the threshold electrodes, and along the threshold electrodes. What is the direction of movement of the strip member? Orthogonal The i-type semiconductor layer is formed by applying high-frequency power to the cathode electrode and decomposing the material gas by plasma discharge while flowing in a direction (width direction of the belt-like member).
[0035]
In the method for forming a photovoltaic element of the present invention, a plurality of kinds of material gases to be introduced into the discharge space between the threshold electrodes are provided, and each is independently guided to the discharge space, thereby moving along the moving direction of the strip member. The i-type semiconductor layer is formed by changing the composition ratio (mixing ratio) of the introduced material gas.
[0036]
The method for forming a photovoltaic device of the present invention having the above-described configuration has the following operation.
[0037]
(1) By using the apparatus configured as described above, a uniform and reproducible discharge state is maintained and controlled over a long period of time, such as forming a semiconductor layer on a strip-like member extending over several hundred meters. In addition, a semiconductor layer whose composition is controlled can be formed.
[0038]
(2) According to the above (1), a high-quality and uniform semiconductor deposited film can be formed continuously and with high yield over the entire length from the beginning to the end of the belt-like member.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
In the photovoltaic device forming apparatus and the forming method according to the present invention, the following configurations are preferable modes.
[0040]
In the apparatus of the present invention, the material of the cathode electrode may be stainless steel and its alloys, aluminum and its alloys, etc. In addition, if it is a material having conductive properties, it should be a material limited to these. There is no. The same applies to the anode electrode material.
[0041]
The apparatus for continuously producing photovoltaic elements of the present invention sequentially produces photovoltaic elements by sequentially passing the film formation space of the photovoltaic elements while continuously moving the strip-like member in the longitudinal direction. Or an apparatus for sequentially manufacturing a stacked photovoltaic element by sequentially passing through a film formation space of a plurality of photovoltaic elements. In addition, the apparatus of the present invention has a structure in which the potential (self-bias) of the cathode electrode installed in the glow discharge space can maintain a positive potential with respect to the ground (anode) electrode including the belt-shaped member, In addition, a plurality of the fin-shaped or block-shaped threshold electrodes are installed in parallel or perpendicular to the transport direction of the band-shaped member, and the gap between the threshold electrodes is set to discharge between the adjacent threshold electrodes. It is an apparatus having a cathode structure having a sufficient interval to maintain and occur.
[0042]
The present invention is characterized in that the surface area in the space in contact with the discharge of the high-frequency power applied cathode electrode installed in the glow discharge space is larger than the surface area in the discharge space of the entire grounded electrode (anode electrode) including the strip member. In addition, the i-type semiconductor thin film is maintained in a state in which glow discharge is generated and the potential (self-bias) of the cathode electrode at the time of forming the semiconductor thin film is maintained at +30 V by using a combination of adjusting the high-frequency power to be applied. It is characterized by depositing.
[0043]
Further, in the present invention, a plurality of the threshold electrodes are installed in the transport direction of the belt-shaped member, and the intervals between the threshold electrodes are sufficient to maintain the discharge between the adjacent threshold electrodes. Thus, a relatively large positive potential can be generated and maintained on the cathode electrode by self-bias. Unlike the bias application method using a direct current (DC) power supply provided separately, this configuration can suppress the occurrence of abnormal discharge due to sparks and the like, so that the discharge can be stably generated and maintained. In addition, since a part of the cathode electrode in which the positive self-bias is generated, that is, the tip of the threshold electrode is relatively close to the band-shaped member, a relatively large positive potential is generated. A bias can be efficiently and stably applied to the deposited film of the band-shaped member through the discharge space. This configuration is, for example, a method of simply shortening the distance between the cathode and the substrate in a cathode electrode structure in a conventional typical apparatus, that is, in a parallel plate type cathode electrode structure in which the cathode electrode area is smaller than the anode (ground) electrode area. This is a self-bias potential that is clearly different from the method of applying a DC voltage to the cathode in combination with a DC power source, which is a DC bias application effect.
[0044]
The present invention is characterized in that an i-type non-single-crystal semiconductor is formed by the apparatus having the above-described structure, and the cathode electrode is maintained at a positive potential, thereby having a positive charge with respect to the belt-shaped member-like deposited film. Since a bias is applied in the direction of irradiating ions, ions existing in the plasma discharge are more efficiently applied in the direction of the belt-like member, and energy can be effectively applied to the deposited film surface by so-called ion bombardment. As a result, the structure relaxation of the film is promoted even at a relatively high deposition rate, the quality and density of the film are improved, and a high-quality semiconductor thin film can be obtained relatively easily. When forming an i-type non-single-crystal semiconductor thin film, the value of the cathode electrode potential described above greatly affects the characteristics of the thin film to be formed, and a high-quality i-type semiconductor layer can be uniformly and reproducibly at a relatively high deposition rate. In order to realize well, the thin film is deposited in a state where the potential of the cathode electrode is maintained at +30 V or higher, preferably +100 V or higher, more preferably +150 V or higher as described above.
[0045]
Further, the present invention is characterized in that the flow direction of the material gas introduced into the discharge space flows in a direction perpendicular to the transport direction of the strip member, that is, the width direction of the strip member, and further the material introduced into the discharge space The gas flows perpendicularly to the transport direction of the strip member between the plurality of threshold electrodes arranged in parallel to the transport direction of the strip member. By changing the composition of the material gas introduced between the threshold electrodes in the transport direction of the strip member, a deposited film whose composition is precisely controlled in the thickness direction can be formed in the strip member shape.
[0046]
Hereinafter, a photovoltaic device forming apparatus according to the present invention will be described.
[0047]
FIG. 1 is a schematic cross-sectional view showing the structure inside the discharge vessel constituting the forming apparatus of the present invention. FIG. 2 is a schematic bird's-eye view showing an example of the cathode electrode shown in FIG. In FIG. 1, 1000 is a conductive strip member, 1001 is a vacuum vessel, 1002 is a cathode electrode, 1003 is a threshold electrode, 1004 is a ground (anode) electrode, 1005 is a lamp heater, 1006 is an exhaust port, and 1007 is a gas introduction pipe. , 1008 is a gas gate, 1009 is an insulating insulator, and 1010 is a discharge space.
[0048]
The cathode electrode 1002 in FIG. 1 has the same structure as the cathode electrode example shown in FIG. 2, and is installed on the ground (anode) electrode 1004 in a state of being electrically insulated by an insulating insulator 1009. . The conductive belt-like member 1000 is supported by an upper space of the cathode electrode 1002 by a plurality of magnet rollers (not shown), and is indicated by an arrow without being physically in contact with the lower cathode electrode and the upper lamp heater 1005. Move in the direction shown. The material gas is introduced from the gas introduction pipe 1007, passes between the strip member and the cathode electrode in a direction perpendicular to the transport direction of the strip member, and is exhausted from the exhaust port 1006 by a vacuum pump (not shown). SUS316 was used as the cathode and anode electrode material. A discharge region of glow discharge that is generated when a high frequency is applied to the cathode electrode from a high frequency electrode (not shown) is a gap between a plurality of ground electrodes 1003 that are part of the cathode electrode, and a band-shaped member and the cathode electrode. And is a region confined by the upper conductive strip member 1000.
[0049]
When the discharge vessel having such a structure is used, the ratio of the area of the cathode electrode to the area of the grounded anode electrode including the belt-shaped member is obviously larger than 1. Furthermore, it is effective that the closest distance (l1 in FIG. 1) between the belt-like member 1000 and the fin-like or block-like threshold-like electrode 1003 which is a part of the cathode electrode is within a range of 5 cm or less. . Further, the interval between the plurality of installed threshold electrodes 1003 is sufficient to maintain the discharge, and the appropriate interval (l2 in FIG. 2) is within the range of 3 cm to 10 cm. It is effective.
[0050]
FIG. 10 is a schematic cross-sectional view showing an example of a discharge vessel having a conventional cathode electrode. As is clear from FIG. 10, the surface area of the cathode electrode 2002 in contact with the discharge space is smaller than the surface area of the grounded anode electrode 2004 including the conductive strip member 2000 in contact with the discharge space. That is, the ratio of the area of the cathode electrode to the area of the grounded anode electrode including the belt-like member is clearly smaller than 1.
[0051]
3 to 7 are schematic plan views of the cathode electrode as viewed from the side of the belt-shaped member, showing the positions where the material gas inlet and exhaust ports are provided in the cathode electrode of FIG. 1 and the flow of the material gas. . The arrows shown in the figure indicate the direction in which the material gas flows.
[0052]
In the deposited film formed on the conductive strip member 1000, in order to precisely control the composition in the film thickness direction, the material gas is introduced into the discharge space between the adjacent threshold electrodes 1003, and between the threshold electrodes 1003, respectively. It flows in a direction perpendicular to the moving direction of the strip member 1000 (width direction of the strip member 1000). Further, the composition ratio (mixing ratio) of the supplied material gas is adjusted along the moving direction of the strip member 1000.
[0053]
The supply position of the material gas, that is, the position where the gas introduction pipe 1007 is provided may be from the cathode electrode facing the belt-like member (FIG. 3) or from a plate connecting adjacent threshold electrodes (FIG. 4). The position of the exhaust port may be provided on the cathode electrode facing the strip member (FIG. 3), or may be provided on a plate connecting adjacent threshold electrodes (FIG. 4). If the flow of the material gas in the discharge space flows at right angles to the moving method of the strip member along the threshold electrode (in the width direction of the strip member), the introduction position of the material gas and the exhaust port position are not limited.
[0054]
5 to 7 show positions where the material gas introduction port and the exhaust port are devised in consideration of the uniformity of various characteristics of the deposited film in the width direction of the band member when the band member is wide. FIG. 5 is a schematic cross-sectional view of the cathode electrode viewed from the belt-like member side. The arrows shown in the figure indicate the direction in which the material gas flows. In order to prevent the distance between the introduction position of the material gas and the exhaust port from becoming too large, the introduction position or exhaust port of the material gas may be arranged in the transport direction of the strip member (FIG. 5), or in the adjacent discharge space. Alternately or staggered (FIG. 6), or by alternating the material gas flow in adjacent discharge spaces (FIG. 7), the plasma uniformity in the width direction of the strip-shaped member in the discharge space is increased. The composition of the deposited film formed on the belt-like member is made uniform in the width direction.
[0055]
8 and 9 are conceptual schematic diagrams showing a method for controlling the flow rate of the material gas introduced into the discharge space.
[0056]
FIG. 8 is a diagram showing a material gas introduction method and a control method for forming a deposited film having a uniform composition in the film thickness direction. The flow rate of the material gas supplied from the gas cylinder 1012 is controlled by the mass flow controller 1011 and the necessary gas is mixed, and then introduced into the discharge space from a gas introduction tube 1007 provided in the vicinity of the threshold cathode electrode by piping. At that time, the material gas is equally distributed by branching the pipe into equal conductance according to the number of introduction points, and is introduced into the discharge space from between the fin-shaped electrodes.
[0057]
FIG. 9 is a diagram illustrating a material gas introduction method and a control method for forming a deposited film having a composition gradient in the film thickness direction. That is, in order to create a composition gradient, the mixing ratio (or flow rate ratio) of a plurality of material gases introduced into the discharge space is changed in the moving direction of the strip member. The flow rate of the material gas supplied from the gas cylinder 1012 is controlled through the mass flow controller 1011 for each gas type, and then led to the vicinity of the threshold cathode electrode by piping. The piping is arranged in parallel with the conveying direction of the belt-shaped member, led to the gas mixing unit 1013 through the small holes, and mixed with other gases led in the same manner. The material gas guided to each gas mixing section is branched (designing the conductance of the branch destination pipe) according to the flow rate led to the gas mixing section by piping through the mass flow controller 1011 and distributed. The mixed gas is introduced into the discharge space from another small hole provided in the gas mixing space through a gas introducing tube 1007 provided between the threshold cathode electrodes.
[0058]
The gap (11 in FIG. 1) between the threshold electrode and the strip member promotes gas mutual diffusion between adjacent discharge spaces, and is important for forming a smooth composition gradient in the film thickness direction of the deposited film. When l1 is wide, interdiffusion is promoted, but the independence between adjacent discharges is dilute.
[0059]
【Example】
Hereinafter, the method for forming a photovoltaic device according to the present invention will be described in detail with specific examples, but the present invention is not limited to these examples.
[0060]
(Example 1)
In this example, the discharge vessel of FIG. 1 was used as an i-type layer forming vessel in the roll-to-roll type continuous plasma CVD apparatus shown in FIG. . At that time, the cathode structure in the discharge vessel of FIG.
[0061]
(1) The closest distance (l1 in FIG. 1) between the belt-like member and the threshold electrode which is a part of the cathode electrode was 0.5 cm.
(2) Eighteen threshold electrodes were installed, and the distance between the threshold electrodes (l2 in FIG. 1) was 5 cm (that is, the cathode electrode length was 105 cm).
(3) The length in the width direction of the band-shaped member of the threshold electrode was 50 cm.
(4) The ratio of the cathode area to the entire grounded anode area including the conductive belt-shaped member was set to 3.0 times.
(5) The material gas was supplied evenly distributed between the threshold electrodes. At that time, the arrangement of the gas introduction port and the exhaust port was the pattern shown in FIG.
[0062]
The single-type photovoltaic element manufacturing apparatus shown in FIG. 11 (FIG. 11) includes a vacuum container 301 and 302 for feeding and winding the belt-like member 101, a first conductive type layer forming vacuum container 601 and an i-type. The layer manufacturing vacuum container 100 and the second conductivity type layer manufacturing vacuum container 602 were configured from an apparatus connected via a gas gate. That is, the i-type layer manufacturing vacuum container 100 is an i-type layer forming container having the cathode electrode configured as described above.
[0063]
In the following, a manufacturing method of the single photovoltaic element shown in FIG. 12 will be described using the manufacturing apparatus of FIG. In FIG. 12, 4001 is a SUS substrate, 4002 is an Ag thin film, 4003 is a ZnO thin film, 4004 is a first conductivity type layer, 4005 is an i type layer, 4006 is a second conductivity type layer, 4007 is ITO, and 4008 is a collection. Electrode.
[0064]
Each layer was continuously produced by the following procedure to form a single type photovoltaic element (element-actual 1). Table 1 shows the manufacturing conditions of each layer.
[0065]
(1) A SUS430BA belt-like member 101 (width 400 mm) in which a vacuum vessel 301 having a substrate feed mechanism is sufficiently degreased and cleaned, and a lower electrode is deposited by sputtering with a silver thin film of 100 nm and a ZnO thin film of 1 μm. A bobbin 303 wound with a length of 200 m and a thickness of 0.13 mm is set, and a vacuum having a belt-shaped member winding mechanism is set through the gas-shaped gate member 101 and each non-single crystal layer forming vacuum vessel The tension was adjusted to the extent that there was no slack through the container 302.
[0066]
(2) Each vacuum vessel 301, 601, 100, 602, 302 is 1 × 10 with a vacuum pump (not shown). ^-Four A vacuum was drawn to below Torr.
[0067]
(3) From the gate gas introduction pipes 131n, 131, 132, 131p to the gas gate, H is used as the gate gas. ₂ Was fed at 700 sccm, and the belt-like member 101 was heated to 350 ° C., 350 ° C., and 250 ° C. by lamp heaters 124 n, 124, and 124 p, respectively. From the gas introduction pipe 605, SiH _Four Gas 40sccm, PH _Three Gas (2% H ₂ Diluted product) 50 sccm, H ₂ 200 sccm of gas, SiH from gas introduction pipes 104a, 104b, 104c _Four 100 sccm of gas each, H ₂ Each gas is 500 sccm, from the gas introduction pipe 606, SiH _Four 10sccm of gas, BF _Three Gas (2% H ₂ Diluted product) 100 sccm, H ₂ 500 sccm of gas was introduced.
[0068]
(4) The conductance valve 307 was adjusted so that the pressure in the vacuum vessel 301 was 1.0 Torr with the pressure gauge 314. The conductance valve (not shown) was adjusted so that the pressure in the vacuum vessel 601 was 1.5 Torr with a pressure gauge (not shown). The conductance valve (not shown) was adjusted so that the pressure in the vacuum vessel 100 was 1.8 Torr with a pressure gauge (not shown). The conductance valve (not shown) was adjusted so that the pressure in the vacuum vessel 602 was 1.6 Torr with a pressure gauge (not shown). The pressure in the vacuum vessel 302 was adjusted by the conductance valve 308 so that the pressure gauge 315 would be 1.0 Torr.
[0069]
(5) 500 W of RF power was introduced into the cathode electrode 603, 200 W of RF power was introduced into the cathode electrode 107, and 600 W of RF power was introduced into the cathode electrode 604.
[0070]
(6) The belt-like member 101 was transported in the direction indicated by the arrow in FIG. 11, and a first conductivity type layer, an i-type layer, and a second conductivity type layer were produced on the belt-like member.
[0071]
(7) On the second conductive type layer, ITO (In ₂ O _Three + SnO ₂ ) Was deposited by vacuum deposition at 80 nm, and Al was further deposited by vacuum deposition at 2 μm as a collector electrode.
[0072]
The photovoltaic element (element-actual 1) of this example was produced by the above steps (1) to (7).
[0073]
[Table 1]

[0074]
(Comparative Example 1)
This embodiment is different from the first embodiment in that the structure of the cathode electrode 603 in the vacuum vessel 100 and the cathode electrode 604 in the vacuum vessel 602 is the parallel plate cathode electrode structure shown in FIG. At that time, the cathode structure had the following dimensions and arrangement.
[0075]
(1) The size of the cathode electrode was 50 cm wide × 130 cm long.
(2) The ratio of the cathode area to the entire grounded anode area including the conductive strip member was 0.6 times.
(3) The material gas flowed through the discharge space on the cathode electrode in the moving direction of the strip member.
[0076]
The production conditions for each layer were set to the values shown in Table 2.
[0077]
The other points were the same as in Example 1, and a single photovoltaic element (element-ratio 1) was formed.
[0078]
[Table 2]

[0079]
Conversion efficiency, characteristic uniformity, and yield of the photovoltaic elements produced in Example 1 (element-actual 1) and Comparative Example 1 (element-ratio 1) were evaluated.
[0080]
The current-voltage characteristics were obtained by cutting out an area of 5 cm square from the center in the width direction and from the end (5 cm from the end) every 10 m of the band-shaped member, and AM-1.5 (100 mW / cm ² ) Installed under light irradiation, measured and evaluated photoelectric conversion efficiency. The yield was measured by measuring the shunt resistance in the dark state of the cut out 5 cm square element, and the resistance value was 1 × 10. ^Three Ω · cm ² The above were counted as non-defective products, and the ratio in the total number was expressed as a percentage and evaluated.
[0081]
Table 3 shows the evaluation results. Each value of Example 1 (element-actual 1) shown in Table 3 is a numerical value normalized by setting the average value of each characteristic of Comparative Example 1 (element-ratio 1) to 1.00.
[0082]
[Table 3]

[0083]
From Table 3, each characteristic of (element-actual 1) is improved as a whole as compared with (element-ratio 1), and in particular, an improvement in open-circuit voltage was recognized, resulting in a conversion efficiency of 1.05 times. It turns out that it improves.
[0084]
As shown in Table 3, the photovoltaic element of Example 1 (element-actual 1) is superior in conversion efficiency to the photovoltaic element of Comparative Example 1 (element-ratio 1), and the present invention The photovoltaic device produced by this production method was found to have excellent characteristics, and the effect of the present invention was proved.
[0085]
The uniformity of characteristics in the width direction of the belt-shaped member is as follows. The photovoltaic elements on the belt-shaped members prepared in Example 1 (element-actual 1) and Comparative Example 1 (element-ratio 1) Cut out in a 5 cm square area at the part (5 cm from the end), AM-1.5 (100 mW / cm ² ) It was installed under light irradiation, the photoelectric conversion efficiency was measured, and the width direction distribution of the photoelectric conversion efficiency was evaluated. Table 4 shows the variation (in%) in the average value of the characteristic values at the center and the end in the width direction.
[0086]
[Table 4]

[0087]
From Table 4, the photovoltaic element of Example 1 (element-actual 1) is superior in characteristic uniformity as compared with the photovoltaic element of comparative example 1 (element-ratio 1). The single-type photovoltaic device produced by the production method was found to have excellent characteristics, and the effect of the present invention was demonstrated.
[0088]
(Example 2)
In this example, the cathode electrode in the vacuum container 100 for forming the i-type layer is the same as in Example 1, the arrangement of the material gas introduction port and the exhaust port is shown in FIG. 6, and the material gas introduction method and control method are shown in FIG. The i-type a-SiGe whose composition is controlled instead of the configuration shown in FIG. _Four : H deposition film was produced on a strip-like member made of SUS430BA (length 100 m).
[0089]
In the following description, the discharge space between the threshold electrodes is referred to as (1), (2),..., (16), (17) from the upper side in the transport direction of the belt-shaped member. In addition, the distance between the threshold electrode and the strip member (l1 in FIG. 1) was 0.5 cm.
[0090]
The material gas supplied between the threshold electrodes is SiH. _Four , GeH _Four , H ₂ Gas was used. GeH _Four The gas supply amount was reduced from (11) between the threshold electrodes (discharge space) located at the central portion toward both ends, and was set to be zero at both ends (1) and (17). On the other hand, SiH _Four The amount of gas supplied was set so as to decrease the supply amount from (1) and (17) between the threshold electrodes (discharge space) located at both ends toward (11) in the center. H ₂ Was supplied evenly between each fin.
[0091]
Table 5 shows the conditions for producing the i-type layer.
[0092]
[Table 5]

[0093]
A central portion in the width direction and a part of the end portion of the band-shaped member on which the deposited film was formed were cut out every 10 m, and composition analysis in the thickness (depth from the surface) direction of the deposited film was performed using SIMS. As a result, a depth profile indicated by a solid line in FIG. 16 was obtained, and it was found that a band profile as shown in FIG. 17 was formed.
[0094]
(Comparative Example 2)
In this example, the cathode electrode structure in the vacuum vessel 100 for forming the i-type layer is the same as the parallel plate cathode electrode structure shown in FIG. 10 (conventional type: in this case, with respect to the entire grounded anode area including the conductive strip member). The ratio of the cathode area is 0.6 times), and the composition-controlled i-type a-SiGe in a stationary state without moving the belt-shaped member _Four : H deposition film was produced on the SUS430BA strip member.
[0095]
As shown in Table 6, composition control of the i-type layer is performed in accordance with the elapse of the film formation time. _Four And GeH _Four The mixing ratio was smoothly changed.
[0096]
[Table 6]

[0097]
The strip-shaped member on which the deposited film was formed was cut out at an arbitrary position and subjected to the same composition analysis as in Example 2. As a result, a smooth depth profile indicated by a broken line in FIG. 16 was obtained, and Example 2 shown in FIG. It was found that the same band profile was formed.
[0098]
Therefore, it became clear that the composition in the thickness direction of the deposited film can be controlled by the apparatus and method of the present invention.
[0099]
It was also confirmed that the composition in the thickness direction of the deposited film can be uniformly formed in the width direction of the belt-shaped member by the apparatus and method of the present invention.
[0100]
Further, the depth profile of the deposited film produced in Example 2 shows a smooth change similarly to the deposited film produced in Comparative Example 2, and the deposited profile according to Example 2 has a smoothly changing band profile. ing. That is, it was found that the composition control in the thickness direction of the deposited film such as the a-SiGe: H graded band gap structure can be smoothly controlled by the apparatus and method of the present invention.
[0101]
(Example 3)
In this example, the a-SiGe: H graded bandgap i-type layer shown in Example 2 was employed, and the single photovoltaic element shown in FIG. 12 was produced under the production conditions shown in Table 7. The photovoltaic element fabricated in this example is referred to as (element-actual 3).
[0102]
The other points were the same as in Example 1.
[0103]
[Table 7]

[0104]
(Comparative Example 3)
In this example, the a-SiGe: H graded bandgap i-type layer is replaced with the a-SiGe: H flat bandgap i-type layer and the a-Si: H flat bandgap i-type (first and second) sandwiching the a-SiGe: H flat bandgap i-type layer. As a three-layer configuration of the buffer layer, the single type photovoltaic device shown in FIG. 14 was manufactured under the manufacturing conditions shown in Table 8. The photovoltaic element produced in this example is referred to as (element-ratio 3).
[0105]
As the i-type layer manufacturing apparatus, the above-mentioned three layers having the parallel plate type cathode electrode structure shown in FIG. 10 (the ratio of the cathode area to the entire grounded anode area including the conductive strip member is 0.6 times). An apparatus similar to that shown in FIG. 11 in which a vacuum container for film formation was arranged was used.
[0106]
The other points were the same as in Example 1.
[0107]
[Table 8]

[0108]
Conversion efficiency, characteristic uniformity, and yield of the photovoltaic devices fabricated in Example 3 (device-actual 3) and Comparative example 3 (device-ratio 3) were evaluated.
[0109]
The current-voltage characteristics were obtained by cutting out an area of 5 cm square from the center in the width direction and from the end (5 cm from the end) every 10 m of the band-shaped member, and AM-1.5 (100 mW / cm ² ) Installed under light irradiation, measured and evaluated photoelectric conversion efficiency. Yield was obtained by cutting out the photovoltaic elements on the band-shaped member produced in Example 3 (element-actual 3) and comparative example 1 (element-ratio 3) in an area of 5 cm square every 10 m. The shunt resistance is measured and the resistance value is 1 × 10 ^Three Ω · cm ² The above were counted as non-defective products, and the ratio in the total number was expressed as a percentage and evaluated.
[0110]
Table 9 shows the evaluation results. Each value of Example 3 (element-actual 3) shown in Table 9 is a numerical value normalized by setting the average value of each characteristic of Comparative Example 3 (element-ratio 3) to 1.00.
[0111]
[Table 9]

Table 9 shows that (element-actual 3) has an overall improvement in characteristics compared to (element-ratio 3), and in particular, an improvement in open-circuit voltage has been recognized, resulting in a conversion efficiency of 1.05 times. It turns out that it improves.
[0112]
As shown in Table 9, the photovoltaic element of Example 3 (element-actual 3) is superior in conversion efficiency to the photovoltaic element of Comparative Example 3 (element-ratio 3), and the present invention. The photovoltaic device produced by this production method was found to have excellent characteristics, and the effect of the present invention was proved.
[0113]
The uniformity of characteristics in the width direction of the belt-shaped member is determined by the width direction center and end of the photovoltaic elements on the belt-shaped member produced in Example 3 (element-actual 3) and Comparative Example 3 (element-ratio 3) every 10 m. Cut out in a 5 cm square area at the part (5 cm from the end), AM-1.5 (100 mW / cm ² ) It was installed under light irradiation, the photoelectric conversion efficiency was measured, and the width direction distribution of the photoelectric conversion efficiency was evaluated. Table 10 shows the variation (in%) in the average value of the characteristic values at the center and the end in the width direction.
[0114]
[Table 10]

[0115]
From Table 10, the photovoltaic element of Example 3 (element-actual 3) is superior in characteristic uniformity as compared with the photovoltaic element of comparative example 3 (element-ratio 3). The single cell type photovoltaic device produced by the production method was found to have excellent characteristics, and the effect of the present invention was proved.
[0116]
(Example 4)
In this example, the forming container of FIG. 1 is used as an i-type layer forming container in a roll-to-roll type continuous plasma CVD apparatus as shown in FIG. 11, and the triple cell type shown in FIG. A photovoltaic device was produced. At that time, the cathode structure in the forming container of FIG.
[0117]
(1) The closest distance (l1 in FIG. 1) between the belt-like member and the threshold electrode that is a part of the cathode electrode was 0.5 cm.
{Circle around (2)} The interval (l2 in FIG. 1) between the plurality of threshold electrodes installed was 5 cm.
(3) The ratio of the cathode area to the entire grounded anode area including the conductive belt member was set to 3.0 times.
[0118]
A continuous plasma CVD apparatus (not shown) employing a roll-to-roll method as shown in FIG. 11 is the first conductive type layer forming vacuum vessel 601 shown in FIG. A device in which the vacuum vessel 100 for producing the mold layer and the vacuum vessel 602 for producing the second conductive type layer are connected via a gas gate is set as one set, and two more sets are added, and a total of 3 sets are repeatedly arranged in series. The device of the configuration. And the formation container mentioned above was installed in all the i-type layer formation containers.
[0119]
Using the apparatus configured as described above, the triple cell type photovoltaic element shown in FIG. 13 was produced under the production conditions shown in Table 11. In FIG. 13, 5001 is a SUS substrate, 5002 is an Ag thin film, 5003 is a ZnO thin film, 5004 is a first conductivity type layer, 5005 is a first i type layer, 5006 is a second conductivity type layer, and 5007 is a first conductivity type layer. , 5008 is the second i-type layer, 5009 is the second conductivity-type layer, 5010 is the first conductivity-type layer, 5011 is the third i-type layer, 5012 is the second conductivity-type layer, 5013 is ITO, and 5014 is a collector electrode.
[0120]
Each of the above layers was continuously produced to form a triple cell type photovoltaic element (element-actual 4). Table 11 shows the conditions for manufacturing each layer.
[0121]
[Table 11]

[0122]
(Comparative Example 4)
In this example, the a-SiGe: H graded bandgap i-type layer is replaced with the a-SiGe: H flat bandgap i-type layer and the a-Si: H flat bandgap i-type (first and second) sandwiching the a-SiGe: H flat bandgap i-type layer. The triple cell type photovoltaic device shown in FIG. 15 was formed as a three-layer structure of the buffer layer. Table 12 shows the conditions for manufacturing each layer. The photovoltaic element fabricated in this example is referred to as (element-ratio 4).
[0123]
As the i-type layer manufacturing apparatus, the above-mentioned three layers having the parallel plate type cathode electrode structure shown in FIG. The apparatus used in Example 4 in which the vacuum container for film formation was arranged was used.
[0124]
The other points were the same as in Example 4.
[0125]
[Table 12]

[0126]
Conversion efficiency, characteristic uniformity, and yield of the photovoltaic elements fabricated in Example 4 (element-actual 4) and Comparative example 4 (element-ratio 4) were evaluated.
[0127]
The current-voltage characteristics were obtained by cutting out an area of 5 cm square from the center in the width direction and from the end (5 cm from the end) every 10 m of the band-shaped member, and AM-1.5 (100 mW / cm ² ) Installed under light irradiation, measured and evaluated photoelectric conversion efficiency. For the yield, the photovoltaic elements on the band-shaped member produced in Example 3 (element-actual 3) and comparative example 1 (element-ratio 3) were cut out in an area of 5 cm square every 10 m, and in the dark state. The shunt resistance is measured and the resistance value is 1 × 10 ^Three Ω · cm ² The above were counted as non-defective products, and the ratio in the total number was expressed as a percentage and evaluated.
[0128]
Table 13 shows the evaluation results. Each value of Example 4 (element-actual 4) shown in Table 13 is a numerical value normalized by setting the average value of each characteristic of Comparative Example 4 (element-ratio 4) to 1.00.
[0129]
[Table 13]

[0130]
From Table 13, each characteristic of (element-actual 4) is improved as a whole as compared with (element-ratio 4), and in particular, an improvement in open-circuit voltage was recognized, resulting in a conversion efficiency of 1.06 times. It turns out that it improves.
[0131]
As shown in Table 13, the photovoltaic element of Example 4 (element-actual 4) is superior in conversion efficiency to the photovoltaic element of comparative example 4 (element-ratio 4). The photovoltaic device produced by this production method was found to have excellent characteristics, and the effect of the present invention was proved.
[0132]
The uniformity of the characteristics in the width direction of the band-shaped member was determined by comparing the photovoltaic elements on the band-shaped members prepared in Example 4 (element-actual 4) and Comparative Example 4 (element-ratio 4) at the center and end in the width direction every 10 m. Cut out in a 5 cm square area at the part (5 cm from the end), AM-1.5 (100 mW / cm ² ) It was installed under light irradiation, the photoelectric conversion efficiency was measured, and the width direction distribution of the photoelectric conversion efficiency was evaluated. Table 14 shows variations (in%) in the average values of the characteristic values at the center and the end in the width direction.
[0133]
[Table 14]

[0134]
From Table 14, the photovoltaic element of Example 4 (element-actual 4) is superior in characteristic uniformity as compared with the photovoltaic element of comparative example 4 (element-ratio 4). The triple cell type photovoltaic device produced by the production method was found to have excellent characteristics, and the effect of the present invention was proved.
[0135]
In addition, by comparing Example 3 with Comparative Example 3 and comparing Example 4 with Comparative Example 4, the apparatus according to the present invention can reduce the size of the apparatus, reduce the weight of incidental equipment, and reduce the amount of material gas. It was found to be effective in reducing consumption.
[0136]
【The invention's effect】
According to the present invention, a structure in which a first conductive semiconductor layer made of non-single crystal, an i-type semiconductor layer, and a second conductive semiconductor layer are sequentially laminated on a continuously moving conductive belt-like member. In forming a photovoltaic device having one or more sets of
As a discharge vessel used for forming the i-type semiconductor layer,
Using a discharge vessel equipped with a threshold cathode electrode aligned perpendicular to the moving direction of the strip member, the cathode potential (self-bias) at the time of discharge is set to a positive potential, and a material gas is introduced between adjacent threshold electrodes, By flowing in the direction perpendicular to the substrate transport direction (substrate width) along the threshold electrode, and by changing the composition ratio (mixing ratio) of the material gases along the substrate transport direction, the i-type semiconductor layer The film composition can be precisely controlled in the film thickness direction.
[0137]
In addition, by adopting the above i-type semiconductor layer, a large number of photovoltaic elements having high photoelectric conversion efficiency, high quality and excellent uniformity over a large area, and more reproducible and less defective are stabilized Can be produced.
[0138]
Furthermore, it is possible to reduce the size of the forming apparatus and reduce the amount of material gas used.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a structure inside a discharge vessel constituting a forming apparatus of the present invention.
2 is a schematic bird's-eye view showing an example of the cathode electrode shown in FIG.
FIG. 3 is a schematic plan view showing an example of a cathode electrode showing a position where a material gas introduction port and a gas exhaust port are provided and a material gas flow.
FIG. 4 is a schematic plan view showing another example of the cathode electrode showing the position where the material gas introduction port and the gas exhaust port are provided and the flow of the material gas.
FIG. 5 is a schematic plan view showing another example of the cathode electrode showing the position where the material gas introduction port and the gas exhaust port are provided and the flow of the material gas.
FIG. 6 is a schematic plan view showing another example of the cathode electrode showing the position where the material gas introduction port and the gas exhaust port are provided and the flow of the material gas.
FIG. 7 is a schematic plan view showing another example of the cathode electrode showing the position where the material gas introduction port and the gas exhaust port are provided and the flow of the material gas.
FIG. 8 is a schematic view showing an example of a method for supplying a material gas introduced into the discharge space.
FIG. 9 is a schematic view showing another example of a method for supplying a material gas introduced into the discharge space.
FIG. 10 is a schematic cross-sectional view showing an example of a discharge vessel having a conventional cathode electrode.
FIG. 11 is a schematic cross-sectional view showing an example of a photovoltaic device forming apparatus according to the present invention.
FIG. 12 is a schematic cross-sectional view of a single cell type photovoltaic device formed by the apparatus and method according to the present invention.
FIG. 13 is a schematic cross-sectional view of a triple cell type photovoltaic device formed by the apparatus and method according to the present invention.
14 is a schematic cross-sectional view of a conventional single cell type photovoltaic element used in Comparative Example 3. FIG.
15 is a schematic cross-sectional view of a conventional triple cell photovoltaic element used in Comparative Example 4. FIG.
16 is a depth profile of the composition analysis by SIMS of the deposited films prepared in Example 2 and Comparative Example 2. FIG.
17 is a band profile of a deposited film manufactured in Example 2 and Comparative Example 2. FIG.
[Explanation of symbols]
100 vacuum vessel,
101 strip members,
103a, 103b, 103c heater,
104a, 104b, 104c gas introduction pipes,
107 cathode electrode,
124n, 124, 124p lamp heater,
129n, 129, 129p, 130 gas gate,
131n, 131, 131p, 132 gas gate introduction pipes,
301, 302 vacuum vessel,
303, 304 bobbins,
305, 306 idle roller,
307, 308 conductance valve,
310, 311 exhaust pipe,
314, 315 pressure gauge,
513 exhaust pipe,
601 and 602 vacuum containers,
603, 604 cathode electrode,
605, 606 gas introduction pipe,
607, 608 exhaust pipe,
1000 conductive strip member,
1001 vacuum vessel,
1002 cathode electrode,
1003 threshold electrode,
1004 Ground (anode) electrode,
1005 lamp heater,
1006 exhaust port,
1007 gas introduction pipe,
1008 Gas gate,
1009 Insulating insulator,
1010 discharge space,
1011 Mass flow controller,
1012 Gas cylinder,
1013 gas mixing section,
2000 conductive strip member,
2001 vacuum vessel,
2002 cathode electrode,
2004 Ground (anode) electrode,
2005 lamp heater,
2006 exhaust vent,
2007 gas introduction pipe,
2008 Gas gate
2009 Insulating insulator
2010 Discharge space
4001 SUS substrate,
4002 Ag thin film,
4003 ZnO thin film,
4004 a first conductivity type layer;
4005 i-type layer,
4006 second conductivity type layer;
4007 ITO,
4008 current collecting electrode,
5001 SUS board
5002 Ag thin film,
5003 ZnO thin film,
5004 a first conductivity type layer;
5005 first i-type layer;
5006 second conductivity type layer;
5007 first conductivity type layer;
5008 second i-type layer;
5009 second conductivity type layer;
5010 first conductivity type layer;
5011 third i-type layer,
5012 second conductivity type layer;
5013 ITO,
5014 current collecting electrode,
6001 SUS substrate,
6002 Ag thin film,
6003 ZnO thin film,
6004 a first conductivity type layer;
6005 a first buffer layer,
6006 i-type layer,
6007 second buffer layer,
6008 second conductivity type layer;
6009 ITO,
6010 current collecting electrode,
7001 SUS substrate,
7002 Ag thin film,
7003 ZnO thin film,
7004 a first conductivity type layer;
7005 a first buffer layer;
7006 a first i-type layer,
7007 a second buffer layer,
7008 second conductivity type layer;
7009 a first conductivity type layer;
7010 first buffer layer,
7011 a second i-type layer,
7012 a second buffer layer;
7013 second conductivity type layer;
7014 a first conductivity type layer;
7015 a third i-type layer,
7016 second conductivity type layer;
7017 ITO,
7018 Current collecting electrode.

Claims (4)

One or more sets of structures in which a first conductive semiconductor layer made of non-single crystal, an i-type semiconductor layer, and a second conductive semiconductor layer are sequentially stacked on a conductive belt-like member that moves continuously. In the photovoltaic device forming apparatus,
The discharge vessel used for forming the i-type semiconductor layer has a discharge space of the whole anode electrode in which the surface area in the discharge space of a high-frequency power application electrode (hereinafter referred to as a cathode electrode) installed in the discharge space includes the surface area of the strip-shaped member. The surface potential of the cathode electrode when glow discharge occurs (hereinafter referred to as self-bias) can be maintained at a positive potential of +30 V or more with respect to the grounded anode electrode including the belt-shaped member, and A plurality of the fin-shaped cathode electrodes (hereinafter referred to as “threshold electrodes”) are provided in a plurality perpendicular to the conveying direction of the strip-shaped member, and the spacing between the respective thru-shaped electrodes is between the adjacent thru-shaped electrodes. The cathode structure having a sufficient interval for maintaining discharge in the substrate and the material gas used for forming the i-type semiconductor layer are adjacent to each other. Is introduced into each discharge space partitioned by the partition-like electrodes from the surface of the cathode electrode between Jo electrodes, flows in a direction perpendicular (the width direction of the belt-shaped member) to the moving direction of the belt-shaped member along said partition-like electrodes A device for forming a photovoltaic device, comprising: a mechanism for applying high-frequency power to the cathode electrode to decompose the material gas by plasma discharge. 2. The gas supply device according to claim 1 , further comprising gas supply means for independently introducing the plurality of types of material gases into the discharge space when the plurality of types of material gases are introduced into the discharge space between the threshold electrodes. The photovoltaic device formation apparatus as described. One or more sets of structures in which a first conductive semiconductor layer made of non-single crystal, an i-type semiconductor layer, and a second conductive semiconductor layer are sequentially stacked on a conductive belt-like member that moves continuously. In the method of forming a photovoltaic device,
As a discharge vessel used for forming the i-type semiconductor layer, the surface area of the discharge space of a high-frequency power application electrode (hereinafter referred to as a cathode electrode) installed in the discharge space is the discharge space of the entire anode electrode including the surface area of the strip-shaped member. The cathode electrode potential (hereinafter referred to as self-bias) when glow discharge occurs is maintained at a positive potential of +30 V or more with respect to the grounded anode electrode including the belt-like member. In addition, a plurality of fin-shaped cathode electrodes (hereinafter referred to as “threshold electrodes”) are provided in a plurality perpendicular to the transport direction of the belt-like member, and the intervals between the respective threshold electrodes are adjacent to each other. Of a photovoltaic device with a discharge vessel having a cathode structure with sufficient spacing to cause and maintain a discharge between the electrode-like electrodes The apparatus is used to introduce a material gas used for forming the i-type semiconductor layer from the cathode electrode surface between adjacent threshold electrodes into each discharge space partitioned by the threshold electrodes, and along the threshold electrodes. The i-type semiconductor layer is formed by applying high-frequency power to the cathode electrode and decomposing the material gas by plasma discharge while flowing in a direction perpendicular to the moving direction of the band-shaped member (width direction of the band-shaped member). A method for forming a photovoltaic element, comprising:   A composition ratio (mixing ratio) of the material gases introduced along the moving direction of the belt-shaped member by providing a plurality of kinds of material gases to be introduced into the discharge space between the threshold electrodes and independently introducing them into the discharge space. The method of forming a photovoltaic element according to claim 3, wherein the i-type semiconductor layer is formed by changing the thickness of the photovoltaic element.

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