Fabrication of the hydrogenated amorphous silicon films containing less hydrogen and its stability against light soaking

The hydrogenated amorphous silicon films containing low hydrogen concentrations are fabricated using a triode deposition system. Introducing a mesh between a cathode and a substrate in a capacitively coupled parallel electrode plasma enhanced chemical vapour deposition system, the prepared films contain low hydrogen concentration (Si-H=4 at.%, Si-H/sub 2//spl Lt/5/spl times/10/sup 20/ cm/sup -3/) at the substrate temperature of 250/spl deg/C. It was observed that the stability of the resulting film is promising, which is confirmed by measuring the changes in neutral spin densities as well as I-V characteristics of Schottky diodes or n-i-p solar cells. Selection of deposition precursors is a key issue for controlling the stability.