Influence of Deposition Conditions on Properties of Hydrogenated Amorphous Silicon Prepared by RF Glow Discharge

Abstract

The electrical and structural properties of amorphous silicon films prepared by pure silane rf glow dicharge have been measured as a function of the rf power, the substrate temperature, the gas flow rate and the gap between the two electrodes. The properties of the deposited films show a very different dependence on the rf power from those reported previously. The films prepared at high rf power density (1–2 W/cm2) reveal a photoconductivity comparable with that of device-grade films prepared at low rf power density (0.02 W/cm2). Increasing the gas flow rate increases the deposition rate up to 70 A/s at 2 W/cm2. The photoconductivity of films prepared at this high deposition rate is 1.2×10-5 (Ω·cm)1 at 600 nm, 1 mW/cm2. This paper discusses the deposition mechanism inducing these results.