COMPOSITION AND STRUCTURE OF EPITAXIAL BETA-SIC FILMS GROWN BY REACTIVE MAGNETRON SPUTTERING ON SI(100) SUBSTRATES

Epitaxial beta-SiC films have been grown on Si(100) substrates by reactive magnetron sputtering in mixed Ar-CH4 discharges as a function of substrate temperature T(s) (700-1200-degrees-C) and methane partial pressures P(CH4) (0.1-1.6 mTorr). Auger electron spectroscopy showed that the carbon content in the films depends on both P(CH4) and T(s). Thus, the decomposition of the CH4 molecules, necessary for SiC formation, occurs both through plasma decomposition and through pyrolysis. X-ray diffraction of as-deposited films grown at T(s) > 900-degrees-C showed only the beta-SiC phase with a pronounced (200) preferred orientation. Cross-sectional transmission electron microscopy showed that films grown at 700-degrees-C consist of a microcrystalline-to-amorphous mixture of beta-SiC and silicon. At T(s) = 900-degrees-C, highly (200) oriented single-phase beta-SiC films were obtained with a relatively sharp interface to silicon, but with stacking faults originating at the silicon interface and propagating throughout the film. Films grown at T(s) = 1000 and 1100-degrees-C were strongly (200) oriented but with a rough interface and a faceted top surface. Also these films contained a high density of stacking faults. The interfacial reaction was also studied by exposing heated silicon surfaces (T(s) = 1200-degrees-C) to a CH4 atmosphere. After 10 min exposure at P(CH4) = 1.5 mTorr a converted epitaxial beta-SiC layer about 50 nm thick formed with a rough interface and a faceted surface. Also these layers contained a high density of stacking faults.