AVS 51st International Symposium
    Thin Films Thursday Sessions
       Session TF-ThA

Paper TF-ThA9
High Stability a-Si:H Films Deposited using Cluster-Suppressed Triode Plasma CVD

Thursday, November 18, 2004, 4:40 pm, Room 303C

Session: Photovoltaic Thin Films
Presenter: K. Koga, Kyushu University, Japan
Authors: K. Koga, Kyushu University, Japan
N. Kaguchi, Kyushu University, Japan
M. Shiratani, Kyushu University, Japan
Y. Watanabe, Kyushu University, Japan
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Reduction of a total volume of amorphous silicon particles below 10 nm in size (clusters) incorporated into a-Si:H films is the key to suppression of light-induced degradation of the films, since the films containing the less volume of clusters show the higher stability.@footnote 1@ In order to realize such reduction, we have deduced a sticking probability s of clusters to a stainless steel mesh from an experiment for which gas containing clusters has been passed through a series of eight meshes. Most clusters are trapped with the first two meshes, indicating s~1. Based on the result, we have employed a cluster-suppressed plasma CVD reactor@footnote 2@ together with a triode discharge for which clusters are trapped with a mesh placed at 18 mm above a substrate. The light-induced degradation of the film qualities has been evaluated using a n@super +@Si/a-Si:H(1µm thick)/Ni Schottky solar cell. The initial and stabilized fill factor FF of the Schottky cell is 0.60 and 0.56, respectively. The degradation ratio of 6.7% is significantly low compared to the ratio of 17% for device quality films deposited using a conventional diode discharge. The stabilized FF= 0.56 surpasses the initial FF= 0.53 for the diode discharge. We will also present experimental results obtained using an "improved version" of the cluster-suppressed triode plasma CVD reactor. @FootnoteText@ @footnote 1@K. Koga, N. Kaguchi, M. Shiratani and Y. Watanabe, J. Vac. Sci. Technol. A 22, (2004) to be published.@footnote 2@M. Shiratani, K. Koga, M. Kai, and Y. Watanabe, Thin Solid Films 427, 1(2003).