ALPHA-BACKSCATTERING USED IN STOICHIOMETRY DETERMINATION OF THIN SIC COATINGS ON SI(100) WAFERS

Monocrystalline cubic silicon carbide (beta) is a very interesting sem iconductor material because of its wide band gap (2.3 eV). In order to reduce the density of defects in epitaxially grown SiC, a buffer laye r obtained by reactive chemical vapour deposition (RCVD) was grown on the Si(100) wafer. We present the results of the analysis of such buff er layers. Alpha backscattering spectrometry was used to determine the carbon depth profiles. It was performed at a 4.3 MeV incident energy in order to take advantage of the 4.26 MeV C-12(alpha, alpha)C-12 reso nance. The cross sections of He-4 scattering on both carbon and silico n, which are required in the analysis were measured. The depth resolut ion, the sensitivity and the accuracy of the backscattering analysis a re discussed together with infrared spectrometry data. The results all ow to optimize the RCVD parameters, especially the temperature and the dilution ratio H-2/C3H8.