Hydrogenated amorphous silicon carbide (a-SiC:H) films were prepared by plasma-enhanced chemical vapor deposition from diethylsilane (C4H12Si) diluted in methane (CH4). The deposition conditions resulted in a highly unstable a-SiC:H film, which reacted with oxygen when exposed to air, forming Si-OH and H-OH bonds and Si-O networks as well. The Rutherford Back Scattering analysis shows 15incorporation. The Fourier transfom infra-red (FT-IR) measurement suggests the presence of a-SiC:O:H component and a-C:H moieties throughout the film. The films were then thermally annealed in vacuum at 450C to removed unstable C-H bonds and Si-OH and H-OH groups creating voids in the film. The removal of C-H, Si-OH and H-OH is evident from the FT-IR spectra. During the annealing process, the film also cross-links and formed a stable a-SiC:O:H film. After annealing, the dielectric constant of the films decreased from 4.2 to 2.1 suggesting the presence of voids/pores in the films.
S. Gangopadhyay, Lahlouh, B., Dr. T. Rajagopalan, Biswas, N., Mehta, N., and Lubguban, J. A., “Creating Voids by Annealing a-SiC: O: H Films Prepared by Plasma-enhanced Chemical Vapor Deposition”, in APS March Meeting Abstracts, 2004.