FORMATION OF BETA-SIC AT THE INTERFACE BETWEEN AN EPITAXIAL SI LAYER GROWN BY RAPID THERMAL CHEMICAL VAPOR-DEPOSITION AND A SI SUBSTRATE

The formation of β-SiC during rapid thermal chemical vapor deposition of an epitaxial Si layer on a (100) Si substrate has been demonstrated using high-resolution cross-sectional transmission electron microscopy and secondary ion mass spectrometry (SIMS) depth profiling. Ellipsoidal β-SiC precipitates (3×10 nm2 average size) were found with a density of (6±1)×109 cm-2 along the epilayer/substrate interface. SIMS revealed about 0.2 monolayer of carbon concentrated at the interface. The precipitates were shown to form during the hydrogen prebake as a result of improper surface cleaning. The crystalline quality of the epitaxial layer, however, was unaffected by the presence of the β-SiC.