Formation of α-Si1−xCx:H and nc-SiC films grown by HWCVD under different process pressure

Abstract In this work, hydrogenated amorphous silicon carbide (α-Si 1− x C x :H) and nanocrystalline SiC (nc-SiC) thin films were deposited by hot wire CVD (HWCVD) using SiH 4 /C 2 H 2 /H 2 gas mixtures. It was found that the films prepared under low gas pressure were α-Si 1− x C x :H and those prepared under high gas pressure were nc-3C-SiC. The α-Si 1− x C x :H films showed enhanced density of C–H n and Si–C bonds with increasing C 2 H 2 fraction, which induced an increase in optical gap from 1.8 to 3.0 eV. For the deposition process of nc-SiC, the E g opt of the deposited films varied from 1.9 eV to 2.5 eV as the filament temperature increased from 1700 to 2100 °C. The deposition rate decreased rapidly from 5.74 nm/min to 0.8 nm/min with increasing T F .