Amorphous silicon-carbon alloys deposited by electron-cyclotron resonance PECVD

Hydrogenated amorphous silicon-carbon alloys are prepared using electron-cyclotron resonance (ECR) plasma-enhanced chemical-vapor deposition. Hydrogen is used as the excitation as in the resonance chamber while silane and methane (or ethylene) are introduced in the main chamber. A minimum of 95% hydrogen dilution is used. The microwave power is kept constant at 150 W. The effect of the type of carbon source gas, silane to carbon source gas ratio, deposition pressure, substrate temperature and hydrogen dilution on the deposition rare, bandgap and Urbach energy are studied. The photoconductivity and the Urbach energy of the ECR-deposited films are compared to those prepared with glow discharge with the same bandgap.