Abstract: High-quality SiC films were successfully prepared on Si(111) substrates by low pressure metal-organic chemical vapor deposition (LP-MOCVD). The mechanism of the heteroepitaxial SiC films on the Si substrates was studied. Many researchers supported that the initiative stage was the Si out-diffusion from the Si substrates. But from the experimental results of heteroepitaxial SiC films grown on the Si substrate and Al2O3 substrate, respectively,it is found that the dominant transport process during the growth of SiC films on the Si substrates, is the C in-diffusion rather than Si out-diffusion. In addition,the results show that the reaction rate will become faster with the increase of the SiH4 flux,but the crystallization will be weakened.

Key words: High-quality SiC films were successfully prepared on Si(111) substrates by low pressure metal-organic chemical vapor deposition (LP-MOCVD). The mechanism of the heteroepitaxial SiC films on the Si substrates was studied. Many researchers supported that the initiative stage was the Si out-diffusion from the Si substrates. But from the experimental results of heteroepitaxial SiC films grown on the Si substrate and Al2O3 substrate, respectively,it is found that the dominant transport process during the growth of SiC films on the Si substrates, is the C in-diffusion rather than Si out-diffusion. In addition,the results show that the reaction rate will become faster with the increase of the SiH4 flux,but the crystallization will be weakened.