AES studies of heteroepitaxial SiC films deposited on Si and on sapphire substrates by MOCVD

Abstract

Auger electron spectroscopy (AES) has been used to investigate the chemical composition of the heteroepitaxial silicon carbide films grown on Si (100) and sapphire (0001) substrates at 900 °C by the MOCVD technique using DEMS precursor. Auger spectra were obtained from the surface and as a function of depth of 2 micron thick SiC films. AES measurements were performed under very high vacuum 10-9 Torr conditions. Surface cleaning and depth profile studies were carried out by using Ar+ ion beam sputtering. Auger spectra of the surface indicate Si LVV, C KLL and O KLL peaks. The Si LVV signals on the 'as prepared' surfaces for both substrates indicated that the silicon was in the oxide state, which was removed after 15 min Ar+ ion cleaning. Depth profile studies showed, that after 20 min of ion cleaning the SiC films possess near stoichiometric composition. Moreover, the C KLL signal on the ion cleaned films showed the carbon in the carbide state. X-ray diffraction analysis of the SiC films on the sapphire (0001) and Si(100) substrates has shown a high intensity single peaks at 35.7o, which indicates the presence of SiC at orientation (111). © 2013 Al-Farabi Kazakh National University.