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

The microstructure, composition, and bonding in hydrogenated amorphous sili con 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 structu re measurements. Hot wire chemical vapor deposition (HW-CVD) was used to gr ow the thin films at substrate temperatures ranging from 200 to 600 K using mono- and trimethylsilane as precursors. It is found that raising the subs trate temperature during HW-CVD leads to films depleted in the higher hydri des (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 methy lated-polysilane backbone to a polycarbosilane backbone. In addition, some crystalline characteristics appear with increasing substrate temperature, d emonstrating that the change of substrate temperature affects both the hydr ogen configuration and the microstructure of the film. Temperature-dependen t growth of thin a-SiC:H films by HW-CVD is compared with the method of ele ctron cyclotron resonance plasma-enhanced (PECVD). (C) 2000 American Instit ute of Physics. [S0021-8979(00)01609-1].