Effect of Ge incorporation on stoichiometric composition of 3C-SiC thin films grown on Si(111) substrates

We present a study on the effect of Ge, deposited on Si(111) substrates prior to the 3C-SiC growth, on the stoichiometric composition of 3C-SiC thin layers grown by SSMBE on Si (111) substrates with Ge amount range from 0 to 1 ML. Secondary Ion Mass Spectroscopy (SIMS) depth profile measurements were used to determine the Si/C intensity ratio present in the 3C-SiC layers and for comparison the Si and C ratios measured in the 3C-SiC! layers were compared with 6H-SiC and 4H-SiC respectively. SIMS investigations revealed that the Si/C intensity ratio in the epitaxial layers is different from the Si/C ratio of the single crystals. The intensity ratio of the 4H-SiC and 6H-SiC samples is found to be 2.01, thus the ratio for the sample without Ge is found to be 2.33 and decreases slightly with the introduction of Ge to 2.1 for the sample with I ML of Ge. It is suggested that this variation is related to a change in the defect densities caused by the Ge incorporation. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.