Temperature effects in the hot wire chemical vapor deposition of amorphous hydrogenated silicon carbon alloy

Abstract

The microstructure, composition, and bonding in hydrogenated amorphous silicon carbon alloy (a-SiC:H) films grown at different substrate temperatures were investigated by a combination of multiple internal reflection-Fourier transform infrared spectroscopy and near edge x-ray absorption fine structure measurements. Hot wire chemical vapor deposition (HW–CVD) was used to grow the thin films at substrate temperatures ranging from 200 to 600 K using mono- and trimethylsilane as precursors. It is found that raising the substrate temperature during HW–CVD leads to films depleted in the higher hydrides (namely SiH3, SiH2, and CH3) in favor of the lower hydrides (SiH and CH). This change marks a transition of the film structure from a highly methylated-polysilane backbone to a polycarbosilane backbone. In addition, some crystalline characteristics appear with increasing substrate temperature, demonstrating that the change of substrate temperature affects both the hydrogen configuration and the microstructure of the film. Temperature-dependent growth of thin a-SiC:H films by HW–CVD is compared with the method of electron cyclotron resonance plasma-enhanced (PECVD).