Dual ion beam deposition of amorphous semiconductor films

Abstract

A sputtering process for efficiently preparing amorphous semiconducting films having a reduced number of localized states is disclosed. In particular, hydrogenated semiconductor films free of polyhydrides may be prepared according to the inventive process. In one application of the process, a silicon target is simultaneously bombarded by separate beams of relatively heavy sputtering ions, such as argon ions, effective in sputtering the target at relatively high rates, and by ions of a substance effective in passivating localized states in amorphous semiconducting films, such as hydrogen ions. The products of this sputtering process are collected on remotely located substrates to form a passivated amorphous semiconductor film. In another application of the process, a target composed of a semiconductor alloy is used with separate sputtering and passivating ion beams directed at the target to deposit a passivated compound semiconductor film. In still another application, one pair of two pairs of sputtering and passivating ion beams are employed to sputter each of two separate elemental semiconductor targets and to deposit a passivated compound semiconductor film. Films deposited according to the invention may be doped and junction structures formed in them during deposition by adding ions of a gaseous dopant to the beam or beams of passivating ions.