Properties of hydrogenated amorphous silicon carbide films prepared at various hydrogen gas flow rates by hot-wire chemical vapor deposition

We prepared hydrogenated amorphous silicon carbide thin films using SiH4, CH4 and H2 gases by the hot-wire chemical vapor deposition method and investigated the influence of hydrogen gas flow rate, F(H2), on their film properties. For F(H2) between 10 and 100 sccm, two groups of films were obtained: high Eg opt. (group H) and low Eg opt. (group L). The Eg opt. in group H decreased from 2.27 to 2.14 eV when F(H2) increased from 10 to 100 sccm, and the Eg opt. in group L decreased from 1.93 to 1.78 eV when F(H2) increased from 50 to 100 sccm. The difference in Eg opt. between the two groups resulted from differences in the electrical power applied to the W wire and deposition on the W wire.