FTIR analysis of a-SiC:H films grown by plasma enhanced CVD

Films of a-SiC:H grown on Si single crystal (1 0 0) by plasma-enhanced chemical vapor deposition (PECVD) are analyzed by Fourier transform infrared (FTIR) spectroscopy. PECVD is performed using a single monomethylsilane (CH3SiCl3) source with hydrogen carrier gas. The hydrogen bond content of the films is determined from the FTIR spectra and compared with the carbon and silicon bond contents as an investigation of the growth process during the atom incorporation phase. The silicon bonding environment is also investigated based on the shift of the FTIR peak of Si-C and Si-H bonds. It is found that the hydrogen bonds of the films is proportional to the square of plasma power density, explainable as due to a combination of two one-step reactions producing non-emissive atomic hydrogen and SiH2. The shift of the SiHn (n = 1,2) peak reveals that the atoms nearest Si in the film are replaced by Si or H atom from C in CHn with increasing hydrogen content. A scheme for film growth in this system is then proposed based on the present and previous findings. (C) 2004 Elsevier B. V. All rights reserved.