Structure Analysis of A-Si 1-xCx:H with Dominant Tetrahedral Si–C Bonds Deposited by Hybrid-Plasma Chemical Vapor Deposition

Hydrogenated amorphous silicon-carbon (a-Si1-x C x :H) was deposited by a new deposition method of hybrid-plasma chemical vapor deposition. In this method, pre-cracked CH4 by a microwave plasma is introduced into a chamber where SiH4 is decomposed by a radio-frequency plasma. A-Si1-x C x :H films deposited by this method show high photoconductivity in the optical-bandgap range from 2.0 to 2.3 eV. The bonding structures in the films deposited by hybrid-plasma CVD were analyzed using Fourier transform infrared absorption and X-ray photoelectron spectroscopy. The films deposited with the microwave plasma contain 1.6–3 times larger tetrahedral Si–C bonds than graphitic C–C bonds, for the same carbon content. Decomposition of CH4 by the microwave plasma leads to a change of the main precursors for the vapor and/or surface reaction, and it is a promising process for obtaining a-Si1-x C x :H with high-performance photoelectric properties resulting from the dominant tetrahedral bonds.