Annealing effect on the optical properties of a-SiC:H films deposited by PECVD

摘要

Effects of annealing temperature (T{sub}a) on the structure of hydrogenated amorphous silicon carbide (a-SiC:H) films prepared by RF plasma chemical vapor deposition (CVD) method are investigated by using Fourier Transform-Infrared Spectrometry (FT-IR), X-ray Photoelectron Spectroscopy (XPS) and UV-VIS spectrophotometer techniques. It is found that an annealing process results in structural rearrangement and evacuation of hydrogen atoms from CH{sub}n and SiH{sub}n bonds. The emission of hydrogen bonded to silicon and carbon responsible for the decrease of optical band gap (E{sub}(opt)) by 0.70 eV in the range of Ta from 573 to 873 K. This hydrogen loss is interpreted in terms of hydrogen molecule formation and outerdiffusion. In addition, the surface morphology of films was investigated by atomic force microscopy (AFM).