Abstract: Disclosed is a method for removing an amorphous silicon photosensitive layer from the metallic surface (e.g., aluminum or stainless steel) of a substrate used in electrophotography. The amorphous silicon layer is removed by exposing such layer to a plasma generated in a fluorine containing atmosphere. Such a plasma provides a high etch rate for the amorphous silicon layer and an extremely high silicon-to-metal etch selectivity. Therefore, the amorphous silicon layer may be rapidly removed by etching at a high power density without risk of damaging the polished metallic surface of the electrophotographic substrate. Moreover, since the etching automatically stops when the metallic surface is reached, no end-point detection is necessary.

Abstract: Disclosed are method and apparatus for producing highly uniform films of photosensitive materials (e.g., amorphous silicon) for electrophotography on large diameter cylindrical metal substrates (e.g., aluminum or stainless steel) by plasma chemical vapor deposition (CVD). The cylindrical substrate is rotatably mounted in a reaction chamber and serves as an electrode. A hollow metallic second electrode in the reaction chamber coaxially surrounds the substrate and is spaced apart therefrom. Hydrogen gas is first introduced into the inter-electrode space between the substrate and the second electrodes, and a high-frequency electric field is applied to the two electrodes to generate a glow discharge for plasma cleaning of the substrate surface. The hydrogen gas is then pumped out of the reaction chamber, and a reaction gas of monosilane (SiH.sub.