Deposition of hydrogenated amorphous silicon films using a microwave plasma chemical vapor deposition method with DC bias

A DC bias is applied to a substrate placed in spatial afterglow plasma created by the double-tubed coaxial line-type microwave plasma chemical vapor deposition system. This DC bias method enables us to control only the ion bombardment energy without changing the ion flux density and the radical density. Hydrogenated amorphous silicon films were deposited, varying only the ion bombardment energy. With increasing ion bombardment energy, the dihydride bonds Si-H₂ and the polyhydride bonds (Si-H₂)n decrease, and the monohydride bonds Si-H and the film density increase.