JP3684012B2 - Method for producing photovoltaic element - Google Patents

Description

（比較例１）
本例では、各ｐ型層を形成する真空容器のカソード電極の形状を平行平板型の構造とし、図４及び図５に示したカソード電極構造とした点が実施例１と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を０．６倍とした。
【００７４】
但し、光起電力素子の作製条件は、実施例１と同じ条件（表１−１）とした。
【００７５】
他の点は実施例１と同様として、ダブルセル型の光起電力素子（素子−比１と呼ぶ）を作製した。
【００７６】
以下では、実施例１及び比較例１で作製した光起電力素子、すなわち（素子−実１）と（素子−比１）に対して、特性均一性、欠陥密度、光劣化、及びシリーズ抵抗の評価を行なった結果について述べる。
【００７７】
特性均一性とは、実施例１及び比較例１で作製した帯状部材上の光起電力素子、すなわち（素子−実１）と（素子−比１）を、１０ｍおきに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、その光電変換効率のバラツキを評価した結果である。第１ｐ層の作製温度が第２ｎ層の作製温度以上のときの（素子−実１）の光電変換効率のバラツキの値を１．００として、相対比較を行なった。
【００７８】
欠陥密度とは、実施例１及び比較例１で作製した帯状部材上の光起電力素子、すなわち（素子−実１）と（素子−比１）、の中央部５ｍの範囲を、５ｃｍ角の面積１００個切出し、逆方向電流を測定することにより、各光起電力素子の欠陥の有無を検出して、欠陥密度を評価した結果である。第１ｐ層の作製温度が第２ｎ層の作製温度以上のときの（素子−実１）の欠陥密度のバラツキの値を１．００として、相対比較を行なった。
【００７９】
光劣化特性とは、実施例１及び比較例１で作製した帯状部材上の光起電力素子、すなわち（素子−実１）と（素子−比１）、の中央部５ｍの範囲を、５ｃｍ角の面積１００個切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、１００００時間放置し、光電変換効率を測定して、その光電変換効率の低下率を評価した結果である。第１ｐ層の作製温度が第２ｎ層の作製温度以上のときの（素子−実１）の低下率のバラツキの値を１．００として、相対比較を行なった。
【００８０】
シリーズ抵抗とは、実施例１及び比較例１で作製した帯状部材上の光起電力素子、すなわち（素子−実１）と（素子−比１）、を１０ｍおきに５ｃｍ角の面積で切出し、ＡＭ−１．５（１００ｍＷ／ｃｍ²）光照射下に設置し、Ｉ−Ｖ特性の開放電圧値近傍の傾きより算出した。第１ｐ層の作製温度が第２ｎ層の作製温度以上のときの（素子−実１）のシリーズ抵抗の値を１．００として、相対比較を行なった。
【００８１】
表１−２は、実施例１で作製した光起電力素子、すなわち（素子−実１）に対して、上述した光電変換効率のバラツキ、欠陥密度、及び光劣化率を調べた結果である。また、表１−３は、比較例１で作製した光起電力素子、すなわち（素子−比１）に対する各評価結果である。
【００８２】
【表１−２】

【００８３】
【表１−３】

表１−２から、実施例１の光起電力素子（素子−実１）は、第１ｐ層の作製温度が第２ｎ層の作製温度より低い場合、変換効率のバラツキ、欠陥密度、光劣化率、シリーズ抵抗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分かった。
【００８４】
また、表１−２と表１−３の比較から、従来の装置より本発明の装置を用いて作製した光起電力素子の方が、全ての評価項目で優れていた。
【００８５】
即ち、ダブルセル型の光起電力素子を形成する際は、少なくとも、第１ｐ層のカソード電極面積を大きくし、かつ、第１ｐ層の作製温度が第２ｎ層の作製温度より低い場合の光起電力素子（素子−実１）の特性が最良であることが分かった。
【００８６】
（実施例２）
本例では、図６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装置を用い、図８に示したトリプルセル型の光起電力素子を作製した点が実施例１と異なる。
【００８７】
特に、トリプルセルを作製するため、各導電型層を作製する真空容器を増設した装置を用いた。すなわち、不図示ではあるが、第１ｎ型層作製用の真空容器６０１、ｉ型層作製用の真空容器１００、第１ｐ型層作製用の真空容器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て、これをさらに２セット増設し、計３セット繰り返して直列に配置した恰好の装置を用いた。
【００８８】
上記トリプルセル型の光起電力素子を作製するとき、第２ｐ型層の作製温度を２５０℃に固定し、第３ｎ型層の作製温度を１００〜３５０℃の範囲で変化させた。
【００８９】
また、各ｐ型層を作製する真空容器のカソード電極の形状は、図３（ｂ）に示した仕切り板形状とした。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を２．９倍とした。
【００９０】
なお、各ｎ型層形成容器および各ｉ型層形成容器としては、平行平板型のＲＦ電極を有する形成容器を用いた。
【００９１】
このような製造装置を用い、表２−１に示す作製条件で、下部電極上に、第１ｎ型層、第１ｉ型層、第１ｐ型層、第２ｎ型層、第２ｉ型層、第２ｐ型層、第３ｎ型層、第３ｉ型層および第３ｐ型層を、順次積み重ねて堆積し、トリプルセル型の光起電力素子（素子−実２と呼ぶ）を作製した。
【００９２】
表２−１には、本例に係る光起電力素子の作製条件を示した。
【００９３】
【表２−１】

（比較例２）
本例では、各ｐ型層を形成する真空容器のカソード電極の形状を平行平板型の構造とし、図４及び図５に示したカソード電極構造とした点が実施例１と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を０．６倍とした。
【００９４】
但し、光起電力素子の作製条件は、実施例２と同じ条件（表２−１）とした。
【００９５】
他の点は実施例２と同様として、トリプルセル型の光起電力素子（素子−比２と呼ぶ）を作製した。
以下では、実施例２及び比較例２で作製した光起電力素子、すなわち（素子−実２）と（素子−比２）に対して、特性均一性、欠陥密度、光劣化、及びシリーズ抵抗の評価を行なった結果について述べる。
【００９６】
これらの評価方法は、実施例１と全く同様とした。すなわち、実施例２の光起電力素子（素子−実２）の特性均一性、欠陥密度、光劣化、シリーズ抵抗について、第２ｐ層の作製温度が第３ｎ層作製温度以上の場合の値をそれぞれ１．００とし、第２ｐ層の作製温度が第３ｎ層作製温度より低い場合、及び、比較例２の光起電力素子（素子−比２）の各特性結果の比較を行なった。
【００９７】
表２−２は、実施例２で作製した光起電力素子、すなわち（素子−実２）に対して、上記諸特性を調べた結果である。また、表２−３は、比較例２で作製した光起電力素子、すなわち（素子−比２）に対する各評価結果である。
【００９８】
【表２−２】

【００９９】
【表１−３】

表２−２から、実施例２の光起電力素子（素子−実２）は、第２ｐ層の作製温度が第３ｎ層の作製温度より低い場合、変換効率のバラツキ、欠陥密度、光劣化率、シリーズ抵抗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分かった。
【０１００】
また、表２−２と表２−３の比較から、従来の装置より本発明の装置を用いて作製した光起電力素子の方が、全ての評価項目で優れていた。
【０１０１】
即ち、トリプルセル型の光起電力素子を形成する際は、少なくとも、第１ｐ層および第２ｐ層のカソード電極面積を大きくし、第１ｐ層の作製温度が第２ｎ層の作製温度より低く、かつ、第２ｐ層の作製温度が第３ｎ層の作製温度より低い場合の光起電力素子（素子−実２）の特性が最良であることが分かった。
【０１０２】
（実施例３）
本例では、ダブルセル型の光起電力素子を作製する際に、各ｐ型層を作製する真空容器のカソード電極の形状を、図３（ｃ）に示した仕切り板形状とした点が実施例１と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を２．９倍とした。
【０１０３】
なお、各ｎ型層形成容器および各ｉ型層形成容器としては、平行平板型のＲＦ電極を有する形成容器を用いた。
【０１０４】
このような製造装置を用い、表１−１に示す作製条件で、下部電極上に、第１ｎ型層、第１ｉ型層、第１ｐ型層、第２ｎ型層、第２ｉ型層および第２ｐ型層を、以下に示すような作製手順により連続的に形成し、ダブルセル型の光起電力素子（素子−実３と呼ぶ）を作製した。
【０１０５】
他の点は、実施例１と同様とした。
【０１０６】
以下では、実施例３で作製した光起電力素子、すなわち（素子−実３）に対して、特性均一性、欠陥密度、光劣化、及びシリーズ抵抗の評価を行なった結果について述べる。
【０１０７】
これらの評価方法は、実施例１と全く同様とした。すなわち、実施例３の光起電力素子（素子−実３）の特性均一性、欠陥密度、光劣化、シリーズ抵抗について、第１ｐ層の作製温度が第２ｎ層作製温度以上の場合の値をそれぞれ１．００とし、第１ｐ層の作製温度が第２ｎ層作製温度より低い場合の各特性結果の比較を行なった。
【０１０８】
表３は、実施例３で作製した光起電力素子、すなわち（素子−実３）に対して、上記諸特性を調べた結果である。
【０１０９】
【表３】

表３から、実施例３の光起電力素子（素子−実３）は、第１ｐ層の作製温度が第２ｎ層の作製温度より低い場合、変換効率のバラツキ、欠陥密度、光劣化率、シリーズ抵抗において優れており、本発明の作製方法により作製したダブルセル型の光起電力素子が、優れた特性を有することが分かった。
【０１１０】
即ち、ダブルセル型の光起電力素子を形成する際は、少なくとも、第１ｐ層のカソード電極面積を大きくし、かつ、第１ｐ層の作製温度が第２ｎ層の作製温度より低い場合の光起電力素子（素子−実３）の特性が最良であることが分かった。
【０１１１】
（実施例４）
本例では、トリプルセル型の光起電力素子を作製する際に、各ｐ型層を作製する真空容器のカソード電極の形状を、図３（ｄ）に示した仕切り板形状とした点が実施例２と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を２．９倍とした。
【０１１２】
なお、各ｎ型層形成容器および各ｉ型層形成容器としては、平行平板型のＲＦ電極を有する形成容器を用いた。
【０１１３】
このような製造装置を用い、表２−１に示す作製条件で、下部電極上に、第１ｎ型層、第１ｉ型層、第１ｐ型層、第２ｎ型層、第２ｉ型層および第２ｐ型層を、以下に示すような作製手順により連続的に形成し、ダブルセル型の光起電力素子（素子−実４と呼ぶ）を作製した。
【０１１４】
他の点は、実施例２と同様とした。
【０１１５】
以下では、実施例４で作製した光起電力素子、すなわち（素子−実４）に対して、特性均一性、欠陥密度、光劣化、及びシリーズ抵抗の評価を行なった結果について述べる。
【０１１６】
これらの評価方法は、実施例１と全く同様とした。すなわち、実施例４の光起電力素子（素子−実４）の特性均一性、欠陥密度、光劣化、シリーズ抵抗について、第２ｐ層の作製温度が第３ｎ層作製温度以上の場合の値をそれぞれ１．００とし、第２ｐ層の作製温度が第３ｎ層作製温度より低い場合、及び、比較例２の光起電力素子（素子−比２）の各特性結果の比較を行なった。
【０１１７】
表４は、実施例４で作製した光起電力素子、すなわち（素子−実４）に対して、上記諸特性を調べた結果である。
【０１１８】
【表４】

表４から、実施例４の光起電力素子（素子−実４）は、第２ｐ層の作製温度が第３ｎ層の作製温度より低い場合、及び、比較例２の光起電力素子（素子−比２）より、変換効率のバラツキ、欠陥密度、光劣化率、シリーズ抵抗において優れており、本発明の作製方法により作製したトリプルセル型の光起電力素子が、優れた特性を有することが分かった。
【０１１９】
即ち、トリプルセル型の光起電力素子を形成する際は、少なくとも、第１ｐ層および第２ｐ層のカソード電極面積を大きくし、第１ｐ層の作製温度が第２ｎ層の作製温度より低く、かつ、第２ｐ層の作製温度が第３ｎ層の作製温度より低い場合の光起電力素子（素子−実４）の特性が最良であることが分かった。
【０１２０】
（実施例５）
本例では、ダブルセル型の光起電力素子を作製する際に、各ｐ型層を作製する真空容器のカソード電極の形状を、図３（ｅ）に示した仕切り板形状とした点が実施例１と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を３．１倍とした。
【０１２１】
また、第１ｉ型層作製用の真空容器１００では、マイクロ波ＣＶＤ法により成膜を行い、第２ｉ型層の形成容器としては平行平板型のＲＦ電極を有する形成容器を用いた。
【０１２２】
なお、各ｎ型層形成容器および各ｉ型層形成容器としては、平行平板型のＲＦ電極を有する形成容器を用いた。
【０１２３】
このような製造装置を用い、表５−１に示す作製条件で、下部電極上に、第１ｎ型層、第１ｉ型層、第１ｐ型層、第２ｎ型層、第２ｉ型層および第２ｐ型層を、順次積み重ねて堆積し、ダブルセル型の光起電力素子（素子−実５と呼ぶ）を作製した。
【０１２４】
他の点は、実施例１と同様とした。
【０１２５】
表５−１には、本例に係る光起電力素子の作製条件を示した。
【０１２６】
【表５−１】

（比較例３）
本例では、第１ｉ型層を形成する真空容器１００のカソード電極の形状を平行平板型の構造とし、図４及び図５に示したカソード電極構造とした点が実施例５と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を０．６倍とした。
【０１２７】
但し、光起電力素子の作製条件は、実施例１と同じ条件（表１−１）とした。
【０１２８】
他の点は実施例１と同様として、ダブルセル型の光起電力素子（素子−比３と呼ぶ）を作製した。
【０１２９】
以下では、実施例５及び比較例３で作製した光起電力素子、すなわち（素子−実５）と（素子−比３）に対して、特性均一性、欠陥密度、光劣化、及びシリーズ抵抗の評価を行なった結果について述べる。
【０１３０】
これらの評価方法は、実施例１と全く同様とした。すなわち、実施例５の光起電力素子（素子−実５）の特性均一性、欠陥密度、光劣化、シリーズ抵抗について、第１ｐ層の作製温度が第２ｎ層作製温度以上の場合の値をそれぞれ１．００とし、第１ｐ層の作製温度が第２ｎ層作製温度より低い場合、及び、比較例３の光起電力素子（素子−比３）の各特性結果の比較を行なった。
【０１３１】
表５−２は、実施例５で作製した光起電力素子、すなわち（素子−実５）に対して、上記諸特性を調べた結果である。また、表５−３は、比較例３で作製した光起電力素子、すなわち（素子−比３）に対する各評価結果である。
【０１３２】
【表５−２】

【０１３３】
【表５−３】

表５−２から、実施例５の光起電力素子（素子−実５）は、第１ｐ層の作製温度が第２ｎ層の作製温度より低い場合、変換効率のバラツキ、欠陥密度、光劣化率、シリーズ抵抗において優れており、本発明の作製方法により作製したダブルセル型の光起電力素子が、優れた特性を有することが分かった。
【０１３４】
また、表５−２と表５−３の比較から、従来の装置より本発明の装置を用いて作製した光起電力素子の方が、全ての評価項目で優れていた。
【０１３５】
即ち、ダブルセル型の光起電力素子を形成する際は、少なくとも、第１ｐ層のカソード電極面積を大きくし、第１ｐ層の作製温度が第２ｎ層の作製温度より低い場合の光起電力素子（素子−実５）の特性が最良であることが分かった。
【０１３６】
（実施例６）
本例では、トリプルセル型の光起電力素子を作製する際に、各ｐ型層を作製する真空容器のカソード電極の形状を、図３（ｆ）に示した仕切り板形状とした点が実施例２と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を２．６倍とした。
【０１３７】
また、第１ｉ型層および第２ｉ型層作製用の真空容器では、マイクロ波ＣＶＤ法により成膜を行い、第３ｉ型層の形成容器としては平行平板型のＲＦ電極を有する形成容器を用いた。
【０１３８】
なお、各ｎ型層形成容器および各ｉ型層形成容器としては、平行平板型のＲＦ電極を有する形成容器を用いた。
【０１３９】
このような製造装置を用い、表６−１に示す作製条件で、下部電極上に、第１ｎ型層、第１ｉ型層、第１ｐ型層、第２ｎ型層、第２ｉ型層、第２ｐ型層、第３ｎ型層、第３ｉ型層および第３ｐ型層を、順次積み重ねて堆積し、トリプルセル型の光起電力素子（素子−実６と呼ぶ）を作製した。
【０１４０】
他の点は、実施例２と同様とした。
【０１４１】
表６−１には、本例に係る光起電力素子の作製条件を示した。
【０１４２】
【表６−１】

（比較例４）
本例では、第１ｉ型層および第２ｉ型層を形成する真空容器のカソード電極の形状を平行平板型の構造とし、図４及び図５に示したカソード電極構造とした点が実施例６と異なる。このカソード電極構造では、導電性帯状部材及びアノード電極の表面積の和に対するカソード電極の表面積の比率を０．６倍とした。
【０１４３】
但し、光起電力素子の作製条件は、実施例２と同じ条件（表２−１）とした。
【０１４４】
他の点は実施例２と同様として、トリプルセル型の光起電力素子（素子−比４と呼ぶ）を作製した。
【０１４５】
以下では、実施例６及び比較例４で作製した光起電力素子、すなわち（素子−実６）と（素子−比４）に対して、特性均一性、欠陥密度、光劣化、及びシリーズ抵抗の評価を行なった結果について述べる。
【０１４６】
これらの評価方法は、実施例１と全く同様とした。すなわち、実施例６の光起電力素子（素子−実６）の特性均一性、欠陥密度、光劣化、シリーズ抵抗について、第２ｐ層の作製温度が第３ｎ層作製温度以上の場合の値をそれぞれ１．００とし、第２ｐ層の作製温度が第３ｎ層作製温度より低い場合、及び、比較例４の光起電力素子（素子−比４）の各特性結果の比較を行なった。
【０１４７】
表６−２は、実施例６で作製した光起電力素子、すなわち（素子−実６）に対して、上記諸特性を調べた結果である。また、表６−３は、比較例４で作製した光起電力素子、すなわち（素子−比４）に対する各評価結果である。
【０１４８】
【表６−２】

【０１４９】
【表６−３】

表６−２から、実施例６の光起電力素子（素子−実６）は、第２ｐ層の作製温度が第３ｎ層の作製温度より低い場合、変換効率のバラツキ、欠陥密度、光劣化率、シリーズ抵抗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分かった。
【０１５０】
また、表６−２と表６−３の比較から、従来の装置より本発明の装置を用いて作製した光起電力素子の方が、全ての評価項目で優れていた。
【０１５１】
即ち、トリプルセル型の光起電力素子を形成する際は、少なくとも、第１ｐ層および第２ｐ層のカソード電極面積を大きくし、第１ｐ層の作製温度が第２ｎ層の作製温度より低く、かつ、第２ｐ層の作製温度が第３ｎ層の作製温度より低い場合の光起電力素子（素子−実６）の特性が最良であることが分かった。
【０１５２】
【発明の効果】
以上説明したように、本発明によれば、大面積にわたって、高品質で優れた均一性を有し、欠陥の少ない、光劣化特性の優れた、シリーズ抵抗の改善された光起電力素子を、高いスループットで大量に再現良く生産することが可能な、光起電力素子の作製方法がえられる。
【図面の簡単な説明】
【図１】図１は、本発明に係るカソード電極を用いた半導体薄膜の作製装置の模式的な断面図であり、作製装置における放電空間の一例を説明するために用いた概念的模式図である。
【図２】図２は、本発明に係る第１ｐ型層の作製温度とシリーズ抵抗との関係を示すグラフである。
【図３】図３は、本発明に係るカソード電極の一例を示した模式図である。
【図４】図４は、従来のカソード電極を用いた半導体薄膜の作製装置の模式的な断面図である。
【図５】図５は、作製装置における放電空間の一例を説明するために用いた概念的模式図である。
【図６】図６は、本発明に係る半導体薄膜の作製装置を用いた、光起電力素子の作製装置の模式的な断面図である。
【図７】図７は、本発明に係るダブルセル型の光起電力素子の概念的な断面図である。
【図８】図８は、本発明に係るトリプルセル型の光起電力素子の概念的な断面図である。
【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 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、
２０００ 導電性帯状部材、
２００１ 真空容器
２００２ カソード電極、
２００４ 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、
４００１ ＳＵＳ基板、
４００２ Ａｇ薄膜、
４００３ ＺｎＯ薄膜、
４００４ 第１ｎ型層、
４００５ 第１ｉ型層、
４００６ 第１ｐ型層、
４００７ 第２ｎ型層、
４００８ 第２ｉ型層、
４００９ 第２ｐ型層、
４０１０ ＩＴＯ、
４０１１ 集電電極、
５００１ ＳＵＳ基板、
５００２ Ａｇ薄膜、
５００３ ＺｎＯ薄膜、
５００４ 第１ｎ型層、
５００５ 第１ｉ型層、
５００６ 第１ｐ型層、
５００７ 第２ｎ型層、
５００８ 第２ｉ型層、
５００９ 第２ｐ型層、
５０１０ 第３ｎ型層、
５０１１ 第３ｉ型層、
５０１２ 第３ｐ型層、
５０１３ ＩＴＯ、
５０１４ 集電電極。[0001]
[Industrial application fields]
The present invention relates to a method for manufacturing a photovoltaic element. More specifically, when a photovoltaic element formed by laminating at least two sets of nip junctions, for example, a photovoltaic element composed of a stacked cell having a double cell or triple cell configuration, series resistance is reduced, Since a semiconductor thin film having excellent deterioration characteristics can be formed, the present invention relates to a manufacturing method in which a photovoltaic element having excellent characteristic uniformity and few defects can be obtained.
[0002]
In particular, the method for producing a photovoltaic element according to the present invention is suitable as a method for mass-producing photovoltaic elements such as solar cells using a roll-to-roll method.
[0003]
[Prior art]
Conventionally, as a method for producing a photovoltaic element using an amorphous silicon film (hereinafter referred to as a-Si film) or the like, the plasma CVD method is generally widely used and commercialized.
[0004]
In the plasma CVD method, silane (SiH), which is a material gas, is used to form a high-quality i-type amorphous semiconductor layer or n-type semiconductor layer. _Four ) Etc., as a gas for adjusting the band gap, _Four , GeH _Four And the like, and the mixed gas is further mixed with hydrogen (H ₂ ) Is often used (about 1 to 100 times). In addition, a method of obtaining a high-quality film through surface reaction by generating high-frequency electric power at a low level to generate many long-lived radicals has been performed.
[0005]
However, in order to increase the deposition rate in the plasma CVD method, it is necessary to supply a large amount of necessary radicals and promote a surface reaction for structural relaxation. For this reason, prescriptions such as raising the substrate temperature have been studied, but this method is disadvantageous for the formation of a P-I-N junction, and thus is not suitable for industrial application.
[0006]
In addition, in order to establish a photovoltaic device to cover power demand, it is essential that the photovoltaic device has a high photoelectric conversion efficiency, excellent characteristic stability, and excellent mass productivity. As required.
[0007]
Therefore, in the production of a photovoltaic device using an a-Si film or the like, electrical, optical, photoconductive or mechanical characteristics, and fatigue characteristics or usage environment characteristics during repeated use, etc. There is a need to improve. In addition, it is necessary to achieve mass production with high reproducibility by high-speed film formation while achieving a large area and uniform film thickness and film quality.
[0008]
As for the photovoltaic element, the semiconductor layer, which is an important constituent element, has a semiconductor junction such as a so-called pn junction or pin junction. When a thin film semiconductor such as a-Si is used, phosphine (PH _Three ), Diborane (B ₂ H ₆ A semiconductor film having a desired conductivity type is obtained by mixing a source gas containing an element serving as a dopant such as silane with silane as a main source gas and performing glow discharge decomposition, and these semiconductor films are formed on a desired substrate. It is known that the above-described semiconductor junction can be easily achieved by sequentially laminating the layers. And when manufacturing such an a-Si type photovoltaic device, the method of providing each film formation chamber for each film formation chamber which provided the independent film formation chamber for producing each semiconductor layer was proposed. ing.
[0009]
For example, US Pat. No. 4,400,409 discloses a continuous plasma CVD apparatus that employs a roll-to-roll method. According to this apparatus, a plurality of glow discharge regions are provided, and a sufficiently long flexible substrate having a desired width is disposed along a path through which the substrate sequentially penetrates the glow discharge regions. It is described that an element having a semiconductor junction can be continuously manufactured by continuously transporting the substrate in the longitudinal direction while depositing a semiconductor layer of a necessary conductivity type in a discharge region. In this specification, a gas gate is used in order to prevent the dopant gas used at the time of manufacturing each semiconductor layer from diffusing and mixing into other glow discharge regions. Specifically, the glow discharge regions are separated from each other by a slit-like separation passage, and further, for example, Ar, H ₂ A means for forming a flow of scavenging gas such as is employed.
[0010]
In addition, as a recently attracting attention for obtaining a good quality film, a research report on the formation of a good quality film using the self-bias generated between the cathode and the anode and the ion species in the capacitively coupled plasma CVD method. Is mentioned. However, this research report has the following two problems.
(1) In the typical discharge vessel internal structure of the prior art, the area of the entire grounded anode electrode including the substrate is often very large compared to the area of the cathode electrode. In the electrode, most of the high-frequency power input is consumed near the cathode electrode. As a result, material gas excitation and decomposition reactions become active only in a limited area near the cathode electrode, and the thin film formation rate increases only on the high-frequency power input side, that is, in the vicinity of the cathode electrode. Even so, the high-frequency power to the substrate, which is the anode electrode, is not sufficiently large, and it is very difficult to obtain a high-quality amorphous semiconductor thin film with the desired high deposition rate. Met.
(2) In a typical discharge vessel structure of the prior art, that is, a discharge vessel having a structure in which the total 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 Although a method of applying a positive potential (bias) to the cathode electrode using a DC is also performed, in such a system, as a result of using a secondary means called a DC power source, a DC current flows in the plasma discharge. It is a system that ends up. As a result, when the DC voltage bias is increased, abnormal discharge such as spark occurs, and it is very difficult to suppress this and maintain 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.
[0011]
In other words, even when the technology described in the above research report is adopted, under high-speed deposition conditions, powder is still generated in the film formation space and taken into the semiconductor thin film that is being deposited, which adversely affects the film quality of the semiconductor thin film. The point was not solved.
[0012]
In particular, the p-type semiconductor layer and the n-type semiconductor layer constituting the photovoltaic device are often set to a very thin thickness of several hundred angstroms at the maximum from the viewpoint of device characteristics. Therefore, when forming a photovoltaic device, particularly a stacked photovoltaic device, the layer thickness uniformity, film adhesion, dopant doping efficiency, property uniformity, and reproducibility affect the device properties. In addition, since it greatly affects the yield of the device, it is important to suppress the generation of the powder and prevent the powder from being taken into the film being deposited.
[0013]
Therefore, in order to obtain a semiconductor thin film such as an a-Si thin film that is uniform both spatially and temporally and with good reproducibility, it is possible to further improve discharge stability over a long period of time, improve reproducibility, and evenly. There is a need for a forming method and apparatus having improved properties. Further, in order to improve the throughput of the apparatus and reduce the cost, a forming method and apparatus capable of increasing the deposition rate while maintaining the quality of the semiconductor thin film are required.
[0014]
When a stacked cell having a double or triple cell configuration is manufactured, the manufacturing conditions for the high-quality p-type semiconductor layer described above and the manufacturing conditions for the n-type semiconductor layer stacked thereon are also included. Need to be optimized.
[0015]
[Problems to be solved by the invention]
In the present invention, when producing a photovoltaic element formed by laminating at least two pairs of nip junctions, for example, a photovoltaic element composed of a stacked cell having a double cell or triple cell configuration, series resistance is reduced, and photodegradation is caused. Since a semiconductor thin film having excellent characteristics can be formed, it is an object of the present invention to provide a method for manufacturing a photovoltaic element having excellent characteristics uniformity and few defects. Further, this manufacturing method is suitable for a method for mass-producing photovoltaic elements such as solar cells using a roll-to-roll method.
[0016]
[Means for Solving the Problems]
The present invention has been completed as a result of intensive studies by the present inventors in order to solve the problems in the prior art and achieve the above object.
[0017]
That is, the present invention
(1) By plasma CVD method , Department In a method for manufacturing a photovoltaic element, in which at least two pairs of nip junctions including an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer are stacked on the surface of a material.
The p-type semiconductor layer is
In the plasma discharge space, it has a cathode electrode to which high frequency power is applied, a belt-like member and an anode electrode that are at ground potential,
The surface area of the cathode electrode in the plasma discharge space is greater than the sum of the surface areas of the strip member and the anode electrode in the plasma discharge space;
The potential of the cathode electrode when glow discharge occurs (hereinafter referred to as self-bias) can maintain a positive potential with respect to the strip member and the anode electrode at the ground potential,
And,
Apparatus for producing a semiconductor thin film having a cathode electrode having a structure in which a shape of a threshold electrode constituting a part of the cathode electrode is a fin shape or a block shape that does not obstruct a flow of a material gas flowing through the threshold electrode. Formed with
And,
When the n-type semiconductor layer is formed by a semiconductor thin film manufacturing apparatus having a capacitively coupled parallel plate type cathode structure,
A method for manufacturing a photovoltaic element, wherein a manufacturing temperature of the p-type semiconductor layer is lower than a manufacturing temperature of the n-type semiconductor layer.
[0018]
Furthermore, as an advanced type that applies this to continuous production equipment,
(2) When the strip member continuously passes through a plurality of connected vacuum vessels, an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer are formed on the surface of the strip member by plasma CVD. In a method for manufacturing a photovoltaic device formed by stacking at least two sets of nip junctions,
The p-type semiconductor layer is
In the plasma discharge space, it has a cathode electrode to which high frequency power is applied, a belt-like member and an anode electrode that are at ground potential,
The surface area of the cathode electrode in the plasma discharge space is greater than the sum of the surface areas of the strip member and the anode electrode in the plasma discharge space;
The potential of the cathode electrode when glow discharge occurs (hereinafter referred to as self-bias) can maintain a positive potential with respect to the strip member and the anode electrode at the ground potential,
And,
The shape of the threshold electrode that constitutes a part of the cathode electrode is a fin shape or a block shape that does not hinder the flow of the material gas flowing through the threshold electrode.
Formed with a semiconductor thin film manufacturing apparatus having the cathode electrode having a structure,
And,
When the n-type semiconductor layer is formed by a semiconductor thin film manufacturing apparatus having a capacitively coupled parallel plate type cathode structure,
A method for manufacturing a photovoltaic element, wherein a manufacturing temperature of the p-type semiconductor layer is lower than a manufacturing temperature of the n-type semiconductor layer.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In the method for producing a photovoltaic device according to the present invention, excitation and decomposition reactions of the material gas are promoted only in a limited part near the cathode electrode, which is a drawback in the conventional technique for producing a p-type thin film semiconductor layer. In this way, the entire discharge space, the anode electrode side including the belt-like member, promotes the excitation and decomposition reaction of the above-mentioned material gas, has a relatively high deposition rate, and efficiently moves on the belt-like member. A semiconductor thin film manufacturing apparatus characterized in that a thin film can be deposited is used. That is, the amount of high-frequency power input to the cathode is adjusted well, the high-frequency power input is used more effectively, the material gas introduced into the discharge space is efficiently excited, decomposed, and high-quality p-type This is a method for producing a photovoltaic device capable of forming a semiconductor thin film on the strip-like member with a relatively high deposition rate with good reproducibility.
[0020]
In the method for producing a photovoltaic device according to the present invention, as a material for the cathode electrode, stainless steel and its alloy, aluminum and its alloy, etc. are conceivable. The material need not be limited to the above. The same applies to the anode electrode material.
[0021]
In the method for producing a photovoltaic device according to the present invention, the photovoltaic device is continuously produced by sequentially passing the film-forming space of the photovoltaic device while continuously moving the belt-like member in the longitudinal direction. Further, in the method of sequentially manufacturing the stacked photovoltaic elements by sequentially passing through the film formation spaces of the plurality of photovoltaic elements, the potential (self-bias) of the cathode electrode installed in the glow discharge space is The ground electrode has a structure capable of maintaining a positive potential with respect to the ground (anode) electrode including the belt-shaped member, and the threshold-shaped electrode having a fin shape or a block shape is parallel to the transport direction of the belt-shaped member or A device having a cathode structure in which a plurality of the electrodes are arranged vertically and the interval between each of the threshold electrodes is sufficient to cause a discharge in the adjacent threshold electrode to be generated and maintained is used.
[0022]
In the present invention, the surface area of the cathode electrode in the plasma discharge space is made larger than the sum of the surface areas of the strip-like member and the anode electrode in the plasma discharge space, and further, the cathode electrode during the formation of the semiconductor thin film is caused by glow discharge. The semiconductor thin film is deposited in a state in which the potential (self-bias) is maintained at a positive potential, more preferably +5 V or more, by adjusting the high-frequency power to be applied. .
[0023]
Furthermore, in the present invention, a plurality of the threshold electrodes are installed in the transport direction of the strip member, and the intervals between the threshold electrodes are sufficiently large 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. This can suppress the occurrence of abnormal discharge due to a spark or the like, unlike a bias application method using a direct current (DC) power source provided separately. As a result, the discharge can be stably generated and maintained, and a part of the cathode electrode in which a positive self-bias is generated, that is, the tip of the threshold electrode is relatively close to the band-shaped member. Therefore, a relatively large positive potential generated can be applied to the strip-shaped deposited film in a stable and efficient manner through the discharge space. This is because, in a parallel plate type cathode electrode structure in which the cathode electrode area, which is typical of the conventional type, is smaller than the anode (ground) electrode area, for example, a method of simply shortening the distance between the cathode and the substrate or a DC power supply is used together. This is a self-bias potential that is clearly different from the method of applying a DC voltage to the cathode, and is a DC bias application effect. Compared to the conventional parallel plate type, the p-type semiconductor layer has the same quality and can be obtained at a relatively low temperature.
[0024]
In the present invention, the positively charged ion species are accelerated by the positive potential of the cathode toward the substrate of the belt-shaped member that is grounded. In particular, in order to produce a high-quality p-type layer, the action of hydrogen ions is important among these ionic species.
[0025]
This positive potential self-bias makes it possible to promote crystallization at a low temperature by the irradiation effect of ions existing in the plasma discharge.
[0026]
Also, an amorphous structure is preferably used as the n-type semiconductor layer stacked on the high-quality p-type semiconductor layer thus manufactured.
[0027]
When the n-type semiconductor layer of the present invention is produced in a capacitively coupled parallel plate discharge space, the production temperature is set higher than the production temperature of the p-type semiconductor layer.
[0028]
In the present invention, the n-type and p-type semiconductor layers are capacitively coupled discharge methods, and a sine wave of 13.56 MHz is preferably used industrially.
[0029]
As described above, in the method for producing a photovoltaic device according to the present invention, the production temperature can be lowered by effectively using ionic species in the method for producing a p-type thin film semiconductor layer, and a photovoltaic device having a stacked structure can be obtained. The characteristics of the power element can be improved.
[0030]
In addition, by using the method for manufacturing a photovoltaic device according to the present invention, it is also effective in realizing the p-type semiconductor layer of the photovoltaic device with a microcrystal silicon thin film, and improves discharge stability over a long period of time. Therefore, it is possible to improve the reproducibility, improve the uniformity, and realize a high-quality semiconductor thin film that is uniform both spatially and temporally with good reproducibility.
[0031]
By using the semiconductor thin film manufacturing apparatus according to the present invention, an extremely good pn junction can be realized particularly in a stacked photovoltaic element, and a higher-quality photovoltaic element can be uniformly formed with good reproducibility. It can be formed continuously.
[0032]
In addition, by using the semiconductor thin film manufacturing apparatus according to the present invention, it is possible to realize a high-quality thin film layer at a relatively high deposition rate, particularly when the p-type semiconductor layer is formed of a microcrystalline silicon thin film. Thus, the throughput of the apparatus can be greatly improved.
[0033]
Furthermore, the method for producing a photovoltaic device according to the present invention solves the above-mentioned problems and provides a photovoltaic device having higher quality and excellent uniformity on a continuously moving belt-like member. Can be produced.
[0034]
Hereinafter, a semiconductor thin film manufacturing apparatus according to the present invention will be described.
[0035]
FIG. 1 is a schematic cross-sectional view showing features in the discharge vessel of the present invention. A cathode electrode 1002 having the same structure as the cathode electrode example shown in FIG. 3C is disposed on the ground (anode) electrode 1004 by being electrically insulated by an insulating insulator 1009. On the cathode electrode, a conductive strip member 1000 is supported by a plurality of magnet rollers (not shown), and is indicated by an arrow without physically contacting the cathode electrode positioned below and the lamp heater 1005 positioned above. It is a structure that moves in the direction to be moved. The material gas is introduced from the gas introduction pipe l007, passes between the belt-like member and the cathode electrode, and is exhausted from the exhaust port 1006 by a vacuum pump (not shown). SUS316 was used as the cathode and anode electrode material.
[0036]
The discharge region of glow discharge generated by high-frequency power is a space between a plurality of ground electrodes 1003 that are part of the cathode electrode and a space between the belt-like member and the cathode electrode. The region is confined by the conductive belt-like member.
[0037]
When the discharge container having such a structure is used, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the strip member and the anode electrode is clearly larger than 1. In addition, the closest distance between the strip-shaped member 1000 and the threshold-shaped electrode 1003 having a fin-like or block-like shape which is a part of the cathode electrode (l in the figure). ₁ ) Is effectively within a range of 5 cm or less. Further, the interval between the plurality of installed threshold electrodes 1003 is sufficient to maintain the occurrence of discharge, and an appropriate interval (l in the figure). ₂ ) Within the range of 3 cm or more and 10 cm or less is effective.
[0038]
4 and 5 are schematic views of a general conventional cathode electrode. As is apparent from this figure, 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 band-like member 2000 in contact with the discharge space. That is, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the strip member and the anode electrode is clearly less than 1.
[0039]
The shape of the cathode electrode of the present invention is not limited to this, and may be, for example, the shape of the cathode electrode schematically shown in FIGS. 3 (a) to 3 (f). In either case, SUS316 was used as the cathode electrode material.
[0040]
FIG. 3A shows an example of a structure in which two strip electrodes are provided at both ends in the width direction in a direction parallel to the transport direction of the belt-shaped member. The structure is such that the material gas can pass between the threshold electrodes at both ends.
[0041]
FIG. 3B and FIG. 3F are examples of a structure in which a plurality of edge-shaped electrodes are provided in a direction perpendicular to the transport direction of the belt-shaped member. A plurality of ventilation holes 1010 through which a material gas can pass are provided on the threshold electrode. The vents may have a size that allows the material gas to pass therethrough and may have a structure that does not impair the function as the cathode electrode. For example, a structure example as shown in FIG.
[0042]
FIG. 3D shows an example of a structure in which a plurality of the strip electrodes are provided in a direction linearly parallel to the transport direction of the belt-shaped member.
[0043]
FIG. 3E shows an example of a structure in which a plurality of continuous electrodes are provided in a meandering manner in parallel with the conveying direction of the belt-shaped member.
[0044]
FIG. 3A to FIG. 3F described above are examples in which the cross-sectional shape of the plurality of threshold electrodes provided in the perpendicular direction and the parallel direction of the band-shaped member is rectangular. However, the cross-sectional shape of the threshold electrode is not limited to a rectangle as long as the gas flow and the local bias of the plasma can be prevented. Moreover, in FIGS. 3A to 3F described above, a rectangular shape constituted by straight sides is shown, but although it is not shown, it may be a shape constituted by curved sides. I do not care. The point is that the cathode electrode has a surface area larger than the surface area of the anode electrode and has a structure that does not hinder the gas flow.
[0045]
By using the semiconductor thin film manufacturing apparatus according to the present invention described above, by producing a photovoltaic device, the above-mentioned problems are solved and the above-mentioned requirements are satisfied, and on the belt-like member that moves continuously, A photovoltaic element having high quality and excellent uniformity and few defects can be produced.
[0046]
In Example 1 to be described later, a cathode electrode structure having the shape shown in FIG. 3A and having a ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode is 2.1 times. The container was used as each p-type layer forming container in the continuous plasma CVD method employing the roll-to-roll method shown in FIG. 6 to produce a double photovoltaic element.
[0047]
Hereinafter, with reference to FIG. 6, a semiconductor thin film manufacturing apparatus used in the double photovoltaic device manufacturing method according to the present invention will be described in detail.
(1) Connecting part
In the present invention, in order to separate the feeding and winding vacuum container of the band-shaped member and the vacuum container for semiconductor film production and to convey the band-shaped member continuously through them, the connecting portion is A gas gate means is preferably used. The capability of the gas gate means is required to have the capability of not diffusing the atmosphere of the raw material gas for the semiconductor film used mutually due to the pressure difference generated between the containers.
Therefore, the basic concept can adopt the gas gating means disclosed in US Pat. No. 4,438,723, but its capability needs to be further improved. Specifically, a maximum of 10 ⁶ It is necessary to be able to withstand about twice the pressure difference, and as the exhaust pump, an oil diffusion pump, a turbo molecular pump, a mechanical booster pump or the like having a large exhaust capacity is preferably used. In addition, the cross-sectional shape of the gas gate is a slit shape or a similar shape, and the dimensional capacity of the gas gate is calculated and designed using a general conductance calculation formula in combination with the overall length and the exhaust capacity of the exhaust pump used. The Furthermore, it is preferable to use a gate gas in combination in order to increase the separation capability. For example, a rare gas such as Ar, He, Ne, Kr, Xe, Rn, or H ₂ And the like. The gate gas flow rate is appropriately determined depending on the conductance of the entire gas gate and the capacity of the exhaust pump to be used.For example, if a point at which the pressure is maximum is provided in the substantially central portion of the gas gate, the gate gas is disposed on both sides from the central portion of the gas gate. The gas flows to the vacuum container side, and mutual gas diffusion between the containers on both sides can be minimized. In practice, the optimum condition is determined by measuring the amount of gas diffused using a mass spectrometer or by analyzing the composition of the semiconductor film.
(2) Strip member
As a material of the strip-shaped member suitably used in the present invention, it is preferable that the material has a desired strength and has a low strength without deformation and distortion at a temperature required when the semiconductor film is produced, Specifically, stainless steel, aluminum and its alloys, iron and its alloys, copper thin plates and their composites such as copper and their alloys, and metal thin films and / or SiO of different materials on their surfaces ₂ , Si _Three N _Four , Al ₂ O _Three Insulating thin film such as ΑlN, etc., which has been surface coated by sputtering, vapor deposition, plating, etc. In addition, a simple metal or alloy and transparent conductive oxide on the surface of a heat-resistant resin sheet such as polyimide, polyamide, polyethylene terephthalate, epoxy, or a composite of these with glass fiber, carbon fiber, boron fiber, metal fiber, etc. (TCO) etc. which performed the electroconductive process by methods, such as plating, vapor deposition, sputtering, application | coating, are mentioned.
[0048]
In addition, the thickness of the belt-shaped member is as thin as possible in consideration of cost, storage space, etc., as long as it is within a range in which the curved shape produced during the conveyance by the conveyance means is maintained. Is desirable. Specifically, it is preferably 0.01 mm to 5 mm, more preferably 0.02 mm to 2 mm, and most preferably 0.05 mm to 1 mm. However, when a thin plate such as a metal is used, the thickness is relatively Even if it is made thin, a desired strength can be easily obtained.
[0049]
The width of the band-shaped member is not particularly limited, and is determined by the size of the semiconductor film manufacturing means or its container.
[0050]
The length of the band-shaped member is not particularly limited, and may be a length that can be wound in a roll shape, which is a longer one that is further elongated by welding or the like. Also good.
[0051]
When the strip member is electrically conductive such as a metal, it may be used as an electrode for direct current extraction, and when it is electrically insulating such as a synthetic resin, Al, Ag, Pt, Au, Ni, Ti, Mo, W, Fe, V, Cr, Cu, stainless steel, brass, nichrome, SnO ₂ , In ₂ O _Three ZnO, SnO ₂ -In ₂ O _Three It is desirable to prepare a current extraction electrode by subjecting a so-called metal simple substance or alloy such as (ITO) or a transparent conductive oxide (TCO) to surface treatment in advance by a method such as plating, vapor deposition or sputtering. .
[0052]
When the strip-shaped member is a non-translucent material such as a metal, it is described that a reflective conductive film for improving the reflectance of the long-wavelength light on the substrate surface is formed on the strip-shaped member. Is preferred. Examples of materials that can be suitably used as the material for the reflective conductive film include Ag, Al, and Cr.
[0053]
In addition, for the purpose of preventing interdiffusion of constituent elements between the substrate material and the semiconductor film or as a buffer layer for preventing a short circuit, a metal layer or the like is used as a reflective conductive film, and the semiconductor film on the substrate is It is preferably provided on the side to be produced. An example of a suitable material for the buffer layer is ZnO.
[0054]
In addition, when the band-shaped member is relatively transparent and a solar cell having a layer structure in which light is incident from the band-shaped member side, a conductive thin film such as the transparent conductive oxide or metal thin film is previously deposited. It is desirable to make it.
[0055]
Further, the surface property of the band-shaped member may be a so-called smooth surface or a minute uneven surface. In the case of a minute uneven surface, it is spherical, conical, pyramidal, etc., and its maximum height (Rmax) is preferably 500 to 5000 mm, so that light reflection on the surface becomes irregular reflection, The optical path length of the reflected light on the surface is increased.
(3) Photovoltaic element
FIG. 7 is a schematic diagram showing the configuration of the photovoltaic element produced in the present invention.
[0056]
The example shown in the figure is a so-called double-type photovoltaic element formed by stacking two photovoltaic elements using two types of semiconductor layers having different band gaps and / or different layer thicknesses as i-type layers. Yes, a strip member 4001 (104), a lower electrode 4003, a first n-type layer 4004, a first i-type layer 4005, a first p-type layer 4006, a second n-type layer 4007, and a second i-type A layer 4008, a second p-type layer 4009, an upper electrode 4010, and a collecting electrode 4011 are included.
[0057]
The example shown in FIG. 8 is a so-called triple-type photovoltaic element configured by stacking three photovoltaic elements using three types of semiconductor layers having different band gaps and / or different layer thicknesses as i-type layers. Yes, a strip member 5001 (104), a lower electrode 5003, a first n-type layer 5004, a first i-type layer 5005, a first p-type layer 5006, a second n-type layer 5007, and a second i-type The layer 5008, the second p-type layer 5009, the third n-type layer 5010, the third i-type layer 5011, the third p-type layer 5012, the upper electrode 5013, and the collecting electrode 5014 are configured.
[0058]
Below, each layer which comprises the said photovoltaic element is demonstrated.
(3-1) n-type and p-type conductivity type layers (that is, first and second conductivity type layers)
The material used for the first and second conductivity type layers in the photovoltaic device of the present invention is a non-single crystal semiconductor composed of one or more atoms of Group III or Group V of the periodic table. Suitable. Furthermore, the conductive layer on the light irradiation side is optimally a microcrystalline semiconductor. The particle size of the microcrystal is preferably 3 nm to 20 nm, and optimally 3 nm to 10 nm.
[0059]
When the conductivity type is n-type, as the additive to be contained, an element belonging to Group V of the periodic table is suitable. Among these, phosphorus (P), nitrogen (N), arsenic (As), and antimony (Sb) are particularly optimal.
[0060]
When the conductivity type is p-type, an element contained in Group III of the periodic table is suitable as an additive to be contained. Of these, boron (B), aluminum (Al), and gallium (Ga) are most suitable.
[0061]
The layer thickness of each conductivity type is preferably 1 nm to 50 nm, optimally 3 nm to 10 nm.
[0062]
Further, in order to reduce light absorption in the conductive layer on the light irradiation side, it is preferable to use a semiconductor layer having a band gap larger than the band gap of the semiconductor constituting the i-type layer. For example, when the i-type layer is amorphous silicon, it is optimal to use non-single-crystal silicon carbide for the conductive type layer on the light irradiation side.
(3-2) i-type layer
As the semiconductor material used for the i-type layer in the photovoltaic device of the present invention, Si, Ge, C, SiC, GeC, SiSn, GeSn, which are composed of one or more kinds of atoms of Group IV of the periodic table, Examples thereof include semiconductors such as SnC. III-V group compound semiconductors: GaAs, GaP, GaSb, InP, InAs, II-VI group compound semiconductors: ZnSe, ZnS, ZnTe, CdS, CdSe, CdTe, I-III-VI group compound semiconductors: CuAlS ₂ , CuAlSe ₂ CuAlTe ₂ , CuInS ₂ , CuInSe ₂ , CuInTe ₂ , CuGAS ₂ , CuGaSe ₂ , CuGaTe, AgInSe ₂ , AgInTe ₂ II-IV-V group compound semiconductors include ZnSiP ₂ ZnGeAs ₂ , CdSiAs ₂ , CdSnP ₂ Cu as an oxide semiconductor ₂ O, TiO ₂ , In ₂ O _Three , SnO ₂ , ZnO, CdO, Bi ₂ O _Three , CdSnO _Four Respectively.
[0063]
【Example】
Below, using the semiconductor thin film and photovoltaic device manufacturing apparatus according to the present invention, a photovoltaic device was formed, and various characteristics of the obtained photovoltaic device were evaluated. However, the present invention is not limited to these examples.
[0064]
(Example 1)
In this example, a double cell type photovoltaic device shown in FIG. 7 was produced using a continuous plasma CVD apparatus employing a roll-to-roll method as shown in FIG.
[0065]
In particular, in order to produce a double cell, an apparatus with an additional vacuum vessel for producing each conductivity type layer was used. That is, although not shown, a set of devices in which the vacuum container 601 for producing the first n-type layer, the vacuum container 100 for producing the i-type layer, and the vacuum container 602 for producing the first p-type layer are connected via a gas gate. As a result, one more set was added, and a favorable device was used in which a total of two sets were repeated and arranged in series.
[0066]
When producing the double cell type photovoltaic device, the production temperature of the second n-type layer was fixed at 300 ° C., and the production temperature of the first p-type layer was changed in the range of 100 to 350 ° C.
[0067]
Moreover, the shape of the cathode electrode of the vacuum vessel for producing each p-type layer was the partition plate shape shown in FIG. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.1 times.
[0068]
In addition, as each n-type layer forming container and each i-type layer forming container, a forming container having a parallel plate type RF electrode was used.
[0069]
The apparatus used in this example has vacuum containers 301 and 302 for feeding and winding the belt-like member 101 as in FIG. 6, and a vacuum container for producing the first n-type layer between the two vacuum containers. 601, first i-type layer preparation vacuum container 100, first p-type layer preparation vacuum container 602, second n-type layer preparation vacuum container 601, second i-type layer preparation vacuum container 100, second p-type layer preparation vacuum container 602 are connected via a gas gate.
[0070]
The structure of each cathode electrode arranged in each vacuum vessel 601, 100, 602 is the cathode electrode structure described above.
[0071]
Using such a manufacturing apparatus, the first n-type layer, the first i-type layer, the first p-type layer, the second n-type layer, the second i-type layer, and the second p are formed on the lower electrode under the manufacturing conditions shown in Table 1-1. The mold layer was continuously formed by the following production procedure to produce a double cell type photovoltaic element (referred to as element-actual 1).
(1) First, a bobbin 303 around which the belt-like member 101 was wound was set in a vacuum container 301 having a substrate delivery mechanism. The strip member 101 is sufficiently degreased and washed, and the lower electrode is made of a SUS430BA strip member (width 120 mm × length 200 m × thickness) deposited by sputtering, with a silver thin film 100 nm and a ZnO thin film 1 μm. 0.13 mm) was used.
(2) The belt-like member 101 was passed through the gas gate and the vacuum vessel for producing each non-single crystal layer to the vacuum vessel 302 having the belt-like member winding mechanism, and the tension was adjusted to the extent that there was no slack.
(3) Each vacuum vessel 301, 601, 100, 602, 601, 100, 602, 302 was evacuated with a vacuum pump (not shown).
(4) From each gate gas introduction pipe to each gas gate, H as the gate gas ₂ Each of the strip members 101 was heated to 350 ° C., 350 ° C., 100 to 350 ° C., 300 ° C., 200 ° C., and 200 ° C. by lamp heaters 124n, 124, 124p, 124n, 124, and 124p.
(5) A predetermined gas was introduced from each gas introduction tube under the conditions shown in Table 1.
(6) The pressure in each vacuum vessel was adjusted with each conductance valve so that the pressure value shown in Table 1 was obtained.
(7) After the pressure adjustment shown in step (6), each RF power shown in Table 1 was introduced into each cathode electrode.
(8) The belt-like member 101 is conveyed in the direction of the arrow in the figure, and the first n-type layer, the first i-type layer, the first p-type layer, the second n-type layer, the second i-type layer, and the second p-type are formed on the belt-like member. Layers were made sequentially.
(9) On the second p-type layer prepared in step (8), ITO (In ₂ O _Three + SnO ₂ ) Was vapor-deposited by 80 nm, and then, as a collecting electrode, Al was vapor-deposited by 2 μm by vacuum vapor deposition, and the production of the photovoltaic element (referred to as element 1) was completed.
[0072]
Table 1-1 shows the conditions for producing the photovoltaic element according to this example.
[0073]
[Table 1-1]

(Comparative Example 1)
This example is different from Example 1 in that the shape of the cathode electrode of the vacuum vessel forming each p-type layer is a parallel plate structure, and the cathode electrode structure shown in FIGS. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 0.6 times.
[0074]
However, the production conditions of the photovoltaic element were the same as those in Example 1 (Table 1-1).
[0075]
The other points were the same as in Example 1, and a double cell type photovoltaic element (referred to as element-ratio 1) was produced.
[0076]
In the following, characteristics uniformity, defect density, photodegradation, and series resistance of the photovoltaic elements produced in Example 1 and Comparative Example 1, that is, (Element-Actual 1) and (Element-Ratio 1) are shown. The results of the evaluation will be described.
[0077]
Characteristic uniformity refers to the photovoltaic elements on the belt-shaped member produced in Example 1 and Comparative Example 1, that is, (Element-Actual 1) and (Element-Ratio 1) cut out at an area of 5 cm square every 10 m. AM-1.5 (100 mW / cm ² It is the result of installing under light irradiation, measuring the photoelectric conversion efficiency, and evaluating the variation in the photoelectric conversion efficiency. Relative comparison was performed by setting the variation value of the photoelectric conversion efficiency of (element-actual 1) when the production temperature of the first p layer is equal to or higher than the production temperature of the second n layer to 1.00.
[0078]
The defect density refers to the range of the central portion 5 m of the photovoltaic elements on the band-shaped member produced in Example 1 and Comparative Example 1, that is, (Element-Actual 1) and (Element-Ratio 1). It is the result of detecting the presence or absence of defects in each photovoltaic element by measuring 100 areas and measuring the reverse current, and evaluating the defect density. Relative comparison was performed by setting the variation value of the defect density of (element-actual 1) to 1.00 when the manufacturing temperature of the first p layer is equal to or higher than the manufacturing temperature of the second n layer.
[0079]
The photodegradation characteristic means that the photovoltaic element on the belt-shaped member produced in Example 1 and Comparative Example 1, that is, the range of the central part 5m of (element-actual 1) and (element-ratio 1) is 5 cm square. Cut out 100 area, AM-1.5 (100mW / cm ² ) It is the result of installing under light irradiation, leaving it to stand for 10,000 hours, measuring the photoelectric conversion efficiency, and evaluating the decreasing rate of the photoelectric conversion efficiency. Relative comparison was performed by setting the variation value of the decrease rate of (element-actual 1) to 1.00 when the production temperature of the first p layer is equal to or higher than the production temperature of the second n layer.
[0080]
The series resistor is a photovoltaic element on the belt-shaped member produced in Example 1 and Comparative Example 1, that is, (Element-Actual 1) and (Element-Ratio 1), cut out at an area of 5 cm square every 10 m, AM-1.5 (100 mW / cm ² ) Installed under light irradiation and calculated from the slope of the IV characteristic near the open circuit voltage value. Relative comparison was performed by setting the value of the series resistance of (element-act.
[0081]
Table 1-2 shows the results of examining the above-described variation in photoelectric conversion efficiency, defect density, and photodegradation rate of the photovoltaic element manufactured in Example 1, that is, (element-actual 1). Table 1-3 shows the evaluation results for the photovoltaic element produced in Comparative Example 1, that is, (element-ratio 1).
[0082]
[Table 1-2]

[0083]
[Table 1-3]

From Table 1-2, in the photovoltaic device of Example 1 (device-actual 1), when the production temperature of the first p layer is lower than the production temperature of the second n layer, variation in conversion efficiency, defect density, and photodegradation rate It was found that the photovoltaic device was excellent in series resistance, and the photovoltaic device produced by the production method of the present invention had excellent characteristics.
[0084]
Moreover, from the comparison of Table 1-2 and Table 1-3, the photovoltaic element produced using the apparatus of this invention was superior to all the evaluation items from the conventional apparatus.
[0085]
That is, when forming a double cell type photovoltaic device, at least the cathode electrode area of the first p layer is increased and the production temperature of the first p layer is lower than the production temperature of the second n layer. It was found that the characteristics of the element (element-actual 1) were the best.
[0086]
(Example 2)
In this example, the triple cell type photovoltaic device shown in FIG. 8 was produced using a continuous plasma CVD apparatus employing a roll-to-roll method as shown in FIG. Different from Example 1.
[0087]
In particular, in order to produce a triple cell, an apparatus having an additional vacuum vessel for producing each conductivity type layer was used. That is, although not shown, a set of devices in which the vacuum container 601 for producing the first n-type layer, the vacuum container 100 for producing the i-type layer, and the vacuum container 602 for producing the first p-type layer are connected via a gas gate. As a result, two more sets were added, and a preferred device was used in which a total of three sets were repeated and arranged in series.
[0088]
When producing the triple cell type photovoltaic device, the production temperature of the second p-type layer was fixed at 250 ° C., and the production temperature of the third n-type layer was changed in the range of 100 to 350 ° C.
[0089]
Moreover, the shape of the cathode electrode of the vacuum vessel for producing each p-type layer was the partition plate shape shown in FIG. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.9 times.
[0090]
In addition, as each n-type layer forming container and each i-type layer forming container, a forming container having a parallel plate type RF electrode was used.
[0091]
Using such a manufacturing apparatus, the first n-type layer, the first i-type layer, the first p-type layer, the second n-type layer, the second i-type layer, and the second p are formed on the lower electrode under the manufacturing conditions shown in Table 2-1. A mold layer, a third n-type layer, a third i-type layer, and a third p-type layer were sequentially stacked and deposited to produce a triple cell type photovoltaic element (referred to as element-actual 2).
[0092]
Table 2-1 shows the conditions for producing the photovoltaic element according to this example.
[0093]
[Table 2-1]

(Comparative Example 2)
This example is different from Example 1 in that the shape of the cathode electrode of the vacuum vessel forming each p-type layer is a parallel plate structure, and the cathode electrode structure shown in FIGS. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 0.6 times.
[0094]
However, the production conditions of the photovoltaic element were the same as those in Example 2 (Table 2-1).
[0095]
Other points were the same as in Example 2, and a triple cell type photovoltaic element (referred to as element-ratio 2) was fabricated.
In the following, characteristics uniformity, defect density, photodegradation, and series resistance of the photovoltaic elements produced in Example 2 and Comparative Example 2, that is, (Element-Actual 2) and (Element-Ratio 2) are shown. The results of the evaluation will be described.
[0096]
These evaluation methods were the same as those in Example 1. That is, for the characteristic uniformity, defect density, photodegradation, and series resistance of the photovoltaic element of Example 2 (element-actual 2), the values obtained when the second p-layer fabrication temperature is equal to or higher than the third n-layer fabrication temperature, respectively. When the preparation temperature of the second p layer was lower than the preparation temperature of the third n layer, and the characteristics of the photovoltaic device of Comparative Example 2 (device ratio 2) were compared.
[0097]
Table 2-2 shows the results obtained by examining the above characteristics of the photovoltaic element manufactured in Example 2, that is, (element-actual 2). Table 2-3 shows the evaluation results for the photovoltaic element produced in Comparative Example 2, that is, (element-ratio 2).
[0098]
[Table 2-2]

[0099]
[Table 1-3]

From Table 2-2, in the photovoltaic device of Example 2 (device-actual 2), when the production temperature of the second p layer is lower than the production temperature of the third n layer, variation in conversion efficiency, defect density, and photodegradation rate It was found that the photovoltaic device was excellent in series resistance, and the photovoltaic device produced by the production method of the present invention had excellent characteristics.
[0100]
Moreover, from the comparison of Table 2-2 and Table 2-3, the photovoltaic element produced using the apparatus of the present invention was superior to all the evaluation items than the conventional apparatus.
[0101]
That is, when forming a triple cell type photovoltaic device, at least the cathode area of the first p layer and the second p layer is increased, the fabrication temperature of the first p layer is lower than the fabrication temperature of the second n layer, and It has been found that the characteristics of the photovoltaic element (element-actual 2) are the best when the production temperature of the second p layer is lower than the production temperature of the third n layer.
[0102]
(Example 3)
In this example, when the double cell type photovoltaic device was manufactured, the shape of the cathode electrode of the vacuum vessel for manufacturing each p-type layer was changed to the partition plate shape shown in FIG. Different from 1. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.9 times.
[0103]
In addition, as each n-type layer forming container and each i-type layer forming container, a forming container having a parallel plate type RF electrode was used.
[0104]
Using such a manufacturing apparatus, the first n-type layer, the first i-type layer, the first p-type layer, the second n-type layer, the second i-type layer, and the second p are formed on the lower electrode under the manufacturing conditions shown in Table 1-1. The mold layer was continuously formed by the production procedure as shown below to produce a double cell type photovoltaic element (referred to as element-actual 3).
[0105]
The other points were the same as in Example 1.
[0106]
Hereinafter, the evaluation results of the characteristic uniformity, defect density, photodegradation, and series resistance of the photovoltaic element manufactured in Example 3, that is, (element-actual 3) will be described.
[0107]
These evaluation methods were the same as those in Example 1. That is, for the characteristic uniformity, defect density, photodegradation, and series resistance of the photovoltaic element of Example 3 (element-actual 3), the values in the case where the first p-layer manufacturing temperature is equal to or higher than the second n-layer manufacturing temperature, respectively. Each characteristic result was compared when the first p-layer fabrication temperature was lower than the second n-layer fabrication temperature.
[0108]
Table 3 shows the results obtained by examining the above characteristics of the photovoltaic element manufactured in Example 3, that is, (element-actual 3).
[0109]
[Table 3]

From Table 3, the photovoltaic element of Example 3 (element-actual 3) has a variation in conversion efficiency, defect density, photodegradation rate, series when the production temperature of the first p layer is lower than the production temperature of the second n layer. It was found that the double cell type photovoltaic device produced by the production method of the present invention was excellent in resistance and had excellent characteristics.
[0110]
That is, when forming a double cell type photovoltaic device, at least the cathode electrode area of the first p layer is increased and the production temperature of the first p layer is lower than the production temperature of the second n layer. It turned out that the characteristic of an element (element-real 3) is the best.
[0111]
(Example 4)
In this example, when producing a triple cell type photovoltaic device, the shape of the cathode electrode of the vacuum vessel for producing each p-type layer was changed to the partition plate shape shown in FIG. 3 (d). Different from Example 2. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.9 times.
[0112]
In addition, as each n-type layer forming container and each i-type layer forming container, a forming container having a parallel plate type RF electrode was used.
[0113]
Using such a manufacturing apparatus, the first n-type layer, the first i-type layer, the first p-type layer, the second n-type layer, the second i-type layer, and the second p are formed on the lower electrode under the manufacturing conditions shown in Table 2-1. The mold layer was continuously formed by the following production procedure to produce a double cell type photovoltaic element (referred to as element-actual 4).
[0114]
The other points were the same as in Example 2.
[0115]
Hereinafter, the evaluation results of the characteristic uniformity, defect density, photodegradation, and series resistance of the photovoltaic element manufactured in Example 4, that is, (element-actual 4) will be described.
[0116]
These evaluation methods were the same as those in Example 1. That is, for the characteristic uniformity, defect density, photodegradation, and series resistance of the photovoltaic element of Example 4 (element-actual 4), the values when the second p-layer fabrication temperature is equal to or higher than the third n-layer fabrication temperature are respectively shown. When the preparation temperature of the second p layer was lower than the preparation temperature of the third n layer, and the characteristics of the photovoltaic device of Comparative Example 2 (device ratio 2) were compared.
[0117]
Table 4 shows the results obtained by examining the above characteristics of the photovoltaic element produced in Example 4, that is, (element-actual 4).
[0118]
[Table 4]

From Table 4, the photovoltaic element of Example 4 (element-actual 4) is the case where the production temperature of the second p layer is lower than the production temperature of the third n layer, and the photovoltaic element of Comparative Example 2 (element- The ratio 2) shows that the conversion efficiency variation, defect density, photodegradation rate, and series resistance are excellent, and the triple cell type photovoltaic device manufactured by the manufacturing method of the present invention has excellent characteristics. It was.
[0119]
That is, when forming a triple cell type photovoltaic device, at least the cathode area of the first p layer and the second p layer is increased, the fabrication temperature of the first p layer is lower than the fabrication temperature of the second n layer, and It has been found that the characteristics of the photovoltaic element (element-actual 4) are best when the production temperature of the second p layer is lower than the production temperature of the third n layer.
[0120]
(Example 5)
In this example, when producing a double cell type photovoltaic device, the shape of the cathode electrode of the vacuum vessel for producing each p-type layer was changed to the partition plate shape shown in FIG. Different from 1. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 3.1 times.
[0121]
Further, in the vacuum container 100 for producing the first i-type layer, the film was formed by the microwave CVD method, and the formation container having the parallel plate type RF electrode was used as the formation container of the second i-type layer.
[0122]
In addition, as each n-type layer forming container and each i-type layer forming container, a forming container having a parallel plate type RF electrode was used.
[0123]
Using such a manufacturing apparatus, the first n-type layer, the first i-type layer, the first p-type layer, the second n-type layer, the second i-type layer, and the second p are formed on the lower electrode under the production conditions shown in Table 5-1. The mold layers were sequentially stacked and deposited to produce a double cell type photovoltaic element (referred to as element-actual 5).
[0124]
The other points were the same as in Example 1.
[0125]
Table 5-1 shows the conditions for producing the photovoltaic element according to this example.
[0126]
[Table 5-1]

(Comparative Example 3)
This example is different from Example 5 in that the shape of the cathode electrode of the vacuum vessel 100 forming the first i-type layer is a parallel plate structure, and the cathode electrode structure shown in FIGS. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 0.6 times.
[0127]
However, the production conditions of the photovoltaic element were the same as those in Example 1 (Table 1-1).
[0128]
The other points were the same as in Example 1, and a double cell type photovoltaic element (referred to as element-ratio 3) was produced.
[0129]
In the following, characteristics uniformity, defect density, photodegradation, and series resistance of the photovoltaic elements manufactured in Example 5 and Comparative Example 3, that is, (Element-Actual 5) and (Element-Ratio 3) are shown. The results of the evaluation will be described.
[0130]
These evaluation methods were the same as those in Example 1. That is, for the characteristic uniformity, defect density, photodegradation, and series resistance of the photovoltaic element of Example 5 (element-actual 5), the values when the first p-layer fabrication temperature is equal to or higher than the second n-layer fabrication temperature are respectively shown. When the first p-layer fabrication temperature was lower than the second n-layer fabrication temperature, the results of the characteristics of the photovoltaic device of Comparative Example 3 (device ratio 3) were compared.
[0131]
Table 5-2 shows the results of examining the above characteristics of the photovoltaic element manufactured in Example 5, that is, (Element-Actual 5). Table 5-3 shows the evaluation results for the photovoltaic element produced in Comparative Example 3, that is, (element-ratio 3).
[0132]
[Table 5-2]

[0133]
[Table 5-3]

From Table 5-2, in the photovoltaic element of Example 5 (element-actual 5), when the production temperature of the first p layer is lower than the production temperature of the second n layer, variation in conversion efficiency, defect density, and photodegradation rate It was found that the double cell type photovoltaic device manufactured by the manufacturing method of the present invention was excellent in series resistance and had excellent characteristics.
[0134]
Moreover, from the comparison of Table 5-2 and Table 5-3, the photovoltaic element produced using the apparatus of this invention was superior to all the evaluation items from the conventional apparatus.
[0135]
That is, when forming a double cell type photovoltaic device, at least the cathode electrode area of the first p layer is increased, and the photovoltaic device when the production temperature of the first p layer is lower than the production temperature of the second n layer ( It was found that the characteristics of the element-actual 5) were the best.
[0136]
(Example 6)
In this example, when producing a triple cell type photovoltaic device, the shape of the cathode electrode of the vacuum vessel for producing each p-type layer was changed to the partition plate shape shown in FIG. Different from Example 2. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 2.6 times.
[0137]
Further, in the vacuum container for producing the first i-type layer and the second i-type layer, the film was formed by the microwave CVD method, and the formation container having the parallel plate type RF electrode was used as the formation container of the third i-type layer. .
[0138]
In addition, as each n-type layer forming container and each i-type layer forming container, a forming container having a parallel plate type RF electrode was used.
[0139]
Using such a manufacturing apparatus, the first n-type layer, the first i-type layer, the first p-type layer, the second n-type layer, the second i-type layer, and the second p are formed on the lower electrode under the production conditions shown in Table 6-1. A mold layer, a third n-type layer, a third i-type layer, and a third p-type layer were sequentially stacked and deposited to produce a triple cell type photovoltaic element (referred to as element-actual 6).
[0140]
The other points were the same as in Example 2.
[0141]
Table 6-1 shows the conditions for producing the photovoltaic element according to this example.
[0142]
[Table 6-1]

(Comparative Example 4)
In this example, the shape of the cathode electrode of the vacuum vessel forming the first i-type layer and the second i-type layer is a parallel plate structure, and the cathode electrode structure shown in FIGS. Different. In this cathode electrode structure, the ratio of the surface area of the cathode electrode to the sum of the surface areas of the conductive strip member and the anode electrode was 0.6 times.
[0143]
However, the production conditions of the photovoltaic element were the same as those in Example 2 (Table 2-1).
[0144]
The other points were the same as in Example 2, and a triple cell type photovoltaic element (referred to as element-ratio 4) was produced.
[0145]
In the following, characteristics uniformity, defect density, photodegradation, and series resistance of the photovoltaic elements produced in Example 6 and Comparative Example 4, that is, (Element-Real 6) and (Element-Ratio 4) are shown. The results of the evaluation will be described.
[0146]
These evaluation methods were the same as those in Example 1. That is, for the characteristic uniformity, defect density, photodegradation, and series resistance of the photovoltaic element of Example 6 (element-actual 6), the values when the second p-layer fabrication temperature is equal to or higher than the third n-layer fabrication temperature are respectively shown. When the preparation temperature of the second p-layer was lower than the preparation temperature of the third n-layer, and the results of the characteristics of the photovoltaic device of Comparative Example 4 (device-ratio 4) were compared.
[0147]
Table 6-2 shows the results of examining the above characteristics of the photovoltaic element manufactured in Example 6, that is, (element-actual 6). Table 6-3 shows the evaluation results for the photovoltaic element manufactured in Comparative Example 4, that is, (element-ratio 4).
[0148]
[Table 6-2]

[0149]
[Table 6-3]

From Table 6-2, in the photovoltaic element of Example 6 (element-actual 6), when the production temperature of the second p layer is lower than the production temperature of the third n layer, variation in conversion efficiency, defect density, and photodegradation rate It was found that the photovoltaic device was excellent in series resistance, and the photovoltaic device produced by the production method of the present invention had excellent characteristics.
[0150]
Moreover, from the comparison of Table 6-2 and Table 6-3, the photovoltaic element produced using the apparatus of the present invention was superior to all the evaluation items than the conventional apparatus.
[0151]
That is, when forming a triple cell type photovoltaic device, at least the cathode area of the first p layer and the second p layer is increased, the fabrication temperature of the first p layer is lower than the fabrication temperature of the second n layer, and It was found that the characteristics of the photovoltaic element (element-actual 6) were the best when the production temperature of the second p layer was lower than the production temperature of the third n layer.
[0152]
【The invention's effect】
As described above, according to the present invention, a photovoltaic device having a large area, high quality, excellent uniformity, few defects, excellent photodegradation characteristics, and improved series resistance. A method for producing a photovoltaic device capable of producing a large amount with high throughput and high reproducibility can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a semiconductor thin film manufacturing apparatus using a cathode electrode according to the present invention, and is a conceptual schematic diagram used for explaining an example of a discharge space in the manufacturing apparatus. is there.
FIG. 2 is a graph showing the relationship between the production temperature of the first p-type layer according to the present invention and the series resistance.
FIG. 3 is a schematic view showing an example of a cathode electrode according to the present invention.
FIG. 4 is a schematic cross-sectional view of a conventional semiconductor thin film manufacturing apparatus using a cathode electrode.
FIG. 5 is a conceptual schematic diagram used for explaining an example of a discharge space in a manufacturing apparatus.
FIG. 6 is a schematic cross-sectional view of a photovoltaic device manufacturing apparatus using the semiconductor thin film manufacturing apparatus according to the present invention.
FIG. 7 is a conceptual cross-sectional view of a double cell photovoltaic element according to the present invention.
FIG. 8 is a conceptual cross-sectional view of a triple cell photovoltaic device according to the present invention.
[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 Anode electrode,
1005 lamp heater,
1006 exhaust port,
1007 gas introduction pipe,
1008 Gas gate,
1009 Insulating insulator,
2000 conductive strip member,
2001 Vacuum container
2002 cathode electrode,
2004 anode electrode,
2005 lamp heater,
2006 exhaust vent,
2007 gas introduction pipe,
2008 Gas gate,
2009 Insulating insulator,
4001 SUS substrate,
4002 Ag thin film,
4003 ZnO thin film,
4004 1st n-type layer,
4005 1st i-type layer,
4006 first p-type layer;
4007 second n-type layer,
4008 second i-type layer,
4009 second p-type layer,
4010 ITO,
4011 current collecting electrode,
5001 SUS substrate,
5002 Ag thin film,
5003 ZnO thin film,
5004 1st n-type layer,
5005 type 1i layer;
5006 1st p-type layer,
5007 second n-type layer;
5008 type 2i layer,
5009 second p-type layer,
5010 third n-type layer,
5011 third i-type layer,
5012 3rd p-type layer,
5013 ITO,
5014 Current collecting electrode.

Claims (3)

By a plasma CVD method, the surface of the section material, n-type semiconductor layer, the nip junction comprising an i-type semiconductor layer and a p-type semiconductor layer, the manufacturing method of a photovoltaic element formed by stacking formed at least two or more sets,
The p-type semiconductor layer is
The plasma discharge space, a cathode electrode high-frequency power is applied, and a member and an anode electrode on the ground, the surface area of the cathode electrode in the plasma discharge space, and pre-Symbol member in the plasma discharge space The potential of the cathode electrode (hereinafter referred to as self-bias) when glow discharge occurs is larger than the sum of the surface areas of the anode electrodes, and maintains a positive potential with respect to the member at the ground potential and the anode electrode. Can
And,
Apparatus for producing a semiconductor thin film having a cathode electrode having a structure in which a shape of a threshold electrode constituting a part of the cathode electrode is a fin shape or a block shape that does not obstruct a flow of a material gas flowing through the threshold electrode. Formed with
And,
When the n-type semiconductor layer is formed by a semiconductor thin film manufacturing apparatus having a capacitively coupled parallel plate type cathode structure, the manufacturing temperature of the p-type semiconductor layer is higher than the manufacturing temperature of the n-type semiconductor layer. A method for manufacturing a photovoltaic element characterized by being low. In a method for manufacturing a photovoltaic device, in which at least two or more pairs of nip junctions composed of an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer are formed on the surface of a belt-shaped member by a plasma CVD method.
The p-type semiconductor layer is
The plasma discharge space has a cathode electrode to which high-frequency power is applied, and a strip-shaped member and an anode electrode that are at ground potential, and the surface area of the cathode electrode in the plasma discharge space is such that the strip-shaped member in the plasma discharge space and The cathode electrode potential (hereinafter referred to as self-bias) when glow discharge occurs is larger than the sum of the surface areas of the anode electrodes, and maintains a positive potential with respect to the strip member and the anode electrode at the ground potential. Can
And,
Apparatus for producing a semiconductor thin film having a cathode electrode having a structure in which a shape of a threshold electrode constituting a part of the cathode electrode is a fin shape or a block shape that does not obstruct a flow of a material gas flowing through the threshold electrode. Formed with
And,
When the n-type semiconductor layer is formed by a semiconductor thin film manufacturing apparatus having a capacitively coupled parallel plate type cathode structure, the manufacturing temperature of the p-type semiconductor layer is higher than the manufacturing temperature of the n-type semiconductor layer. A method for manufacturing a photovoltaic element characterized by being low. When the band-shaped member continuously passes through a plurality of connected vacuum vessels, a nip junction comprising an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer is formed on the surface of the band-shaped member by plasma CVD. In a method for producing a photovoltaic device formed by laminating at least two or more sets,
The p-type semiconductor layer is
The plasma discharge space has a cathode electrode to which high-frequency power is applied, and a strip-shaped member and an anode electrode that are at ground potential, and the surface area of the cathode electrode in the plasma discharge space is such that the strip-shaped member in the plasma discharge space and The cathode electrode potential (hereinafter referred to as self-bias) when glow discharge occurs is larger than the sum of the surface areas of the anode electrodes, and maintains a positive potential with respect to the strip member and the anode electrode at the ground potential. Can
And,
Apparatus for producing a semiconductor thin film having a cathode electrode having a structure in which a shape of a threshold electrode constituting a part of the cathode electrode is a fin shape or a block shape that does not obstruct a flow of a material gas flowing through the threshold electrode. Formed with
And,
When the n-type semiconductor layer is formed by a semiconductor thin film manufacturing apparatus having a capacitively coupled parallel plate type cathode structure, the manufacturing temperature of the p-type semiconductor layer is higher than the manufacturing temperature of the n-type semiconductor layer. A method for manufacturing a photovoltaic element characterized by being low.

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