硅基片上异质外延SiC的机理研究(英文)

Studies of the Heteroepitaxial SiC Films on the Si Substrates

本文利用低压高温MOCVD系统 ,成功地在Si(111)基片上外延出了具有高质量的SiC薄膜 ,并对其反应机理做了一些初步的研究。大部分观点认为 ,SiC/Si的异质外延 ,其最初的状态应该为Si衬底中Si的扩散。但是 ,本文通过在不同流量比的条件下 ,SiC薄膜在Si基片以及Al2 O3 基片上外延的比较 ,发现在SiC/Si的异质外延过程中起重大作用的并非Si衬底中Si的扩散 ,而是很大程度上作用于C向Si衬底的扩散。同时 ,还发现反应速率的快慢受SiH4流量所限制。当SiH4流量增加时 ,反应速率会明显加快 ,但是结晶质量会相对变差。

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 Al_2O_3 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 SiH_4 flux,but the crystallization will be weakened.