Helicon wave plasma chemical vapor deposition of nanocrystalline silicon carbide films at low substrate temperature

摘要

Silicon carbide thin films have been deposited by helicon wave plasma enhanced chemical vapor deposition (HW-PECVD) technique under the conditions of variant deposition temperatures from 300 to 600℃. Silane, methane and hydrogen are used as reactive gas. The structural properties of the deposited films are characterized using Fourier transform infrared (FTIR), scan electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet-visible optical absorption techniques. Detailed analysis of the FTIR spectra indicates that the onset of growing nanocrystalline SiC films at low substrate temperature is closed related with the high plasma ionization rate of helicon wave plasma and the condition of low working gas pressure and strong hydrogen dilution in experiment. The SEM and TEM measurements confirm that the structure of the deposited films is nanocrystalline SiC grains embedded in amorphous matrix and the size of the crystalline gains increases with substrate temperature.