Evaluated of ITO/a-Si interface fabricated by RPD technique.
Tappei Nishihara1, Takefumi Kamioka1, Hiroki Kanai1, Yoshio Ohshita2, Hideki Matsumura3, Satoshi Yasuno4, Ichiro Hirosawa4, Astushi Ogura1
1Meiji Univ., Kawasaki-shi, Kanagawa, Japan
/2Toyota Technological Institute, Nagoya, Aichi, Japan
/3Japan Institute of Science and Technology, Noumi, Ishikawa, Japan
/4JASRI, Sayo-gun, Hyogo, Japan

We evaluated the ITO/p-type a-Si interface for Si heterojunction solar cells using XPS and TEM. It was found that ITO/a-Si interface which is 20 nm from the surface is oxidized by using non-destructive and non-contact HAXPES. The ITO/a-Si interface was oxidized during ITO film deposition by RPD technique, which leads to an increase in contact resistance. The chemical bonding states at the ITO/a-Si interface was modified by post deposition annealing (PDA). The TEM and the EDX mapping images revealed the interdiffusion of Si and Sn resulting in the interface roughness enhancement and the possible In precipitation in the a-Si layer.