Substrate shield for preventing the deposition of nonhomogeneous films

摘要

Apparatus for shielding substrates from plasma developed adjacent the ends of r.f. powered cathodes, the apparatus adapted for use in a glow discharge deposition system in which successive amorphous semiconductor layers are deposited onto a substrate. The deposition system includes at least one deposition chamber into which process gases are introduced and disassociated in the presence of electrodynamic fields created between a cathode and a substrate. The shielding apparatus of the present invention comprises a pair of relatively narrow, elongated plates adapted to be spacedly disposed in the deposition chamber so as to lie in a plane substantially parallel to the plane of the substrate. By disposing one of the plates adjacent each of the ends of the cathode, only homogeneous semiconductor films formed by uniform electrodynamic fields produced adjacent the central portion of the cathode are deposited onto the substrate. The shielding plates are preferably coated with a polyimide film to prevent discharge in the area between the shielding plates and the substrate.