Room-temperature deposition of a-SiC:H thin films by ion-assisted plasma-enhanced CVD

Tetramethylsilane (TMS) diluted highly with hydrogen is used for depositing a-SiC:H thin films at room temperature under varying degrees of ion bombardment in a 13.56 MHz r.f.-powered, asymmetrical plasma reactor. An impedance analysis is used to estimate apparent ion energy and other plasma parameters such as electron density and the degree of ionization. The a-SiC:H films obtained under high ion bombardment show densities comparable to those deposited at high temperatures; are transparent in most of the visible and IR regions; are resistant to etching in buffered HF solution; and exhibit excellent adhesion to various substrates including silicon wafer, quartz, aluminum, and polymers such as polycarbonate and polyimide. FTIR studies of the films show varying bond structures depending on the level of ion bombardment. When the apparent ion energy flux is increased, the hydrogen content in the film decreases and the level of crosslinking appears to increase.