Influence of sputtering conditions on H content and SiH bonding in aSi: H alloys

Abstract

The influence of sputtering conditions on H concentration and SiH bonding has been determined for the case of diode reactive sputtering of Si in ArH mixtures, and a simple model for SiH reaction kinetics has been developed. H content and SiH bonding can be varied and controlled over wide ranges by appropriate selection of sputtering conditions. SiH reaction kinetics are found to be governed primarily by deposition rate (reaction time), H partial pressure (H availability) and possibiy substrate temperature (mobility of Si and H on the surface of the growing film). H concentration increases with decreasing deposition rate and increasing H partial pressure. SiH bonding increases with increasing deposition rate and decreasing H partial pressure. Polymerization of H and Si (SiH 2, SiH 3) occurs for lowest deposition rates and highest H partial pressures. Polymerization reactions are enhanced in films deposited at very high target power densities. The high power density causes substrate temperature to be higher than expected, and the enhanced polymerization may be due to increased Si and H surface mobility at the elevated temperatures.