Structural analysis of nanocrystalline SiC thin films grown on silicon by ECR plasma CVD

Wide bandgap emitters on crystalline substrates are an active area of resea rch for use in heterojunction silicon solar cells. We have deposited high c onductivity SIC containing large concentrations of beta-SiC crystallites. T he effect of sample temperature and gas concentrations on the stoichiometry of the material has been investigated. Depending on process parameters, we find these films consist of varying concentrations of beta-SiC crystallite s, amorphous silicon, amorphous silicon carbide alloys and C-C phases. The contribution of these material features to high and low conductivity in the se films is assessed here. In order to facilitate this analysis we have use d elastic recoil detection analysis (ERDA) and secondary ion mass spectrome try (SIMS) for atomic concentrations. Raman spectroscopy has been used for the detection of amorphous silicon, amorphous SiC and carbon based phases i n the films. X-ray diffractometry has also been used to determine the cryst allinity. The results from these techniques are correlated with film proper ties. (C) 1999 Elsevier Science S.A. All rights reserved.