AES Studies of Heteroepitaxial SiC Films Deposited on Si and on Sapphire Substrates by MOCVD

Abstract

<p>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 35.7°, which indicates the presence of SiC at orientation (111).</p>