Spectroscopic investigations of the role of Ge in modifying the Si to SiC conversion process

The influence of Ge on the conversion process of Si to SiC was studied by depositing Ge and C on Si(111) followed by a stepwise annealing procedure. After the annealing step, the carbon deposited on the surface was completely converted into SiC. In the case of Ge predeposition, the SiC amount detected by XPS, AES and ellipsometry was lower compared to the reference sample in which no Ge was predeposited on the Si(111) surface. Therefore, Ge lowers the probability of SiC formation in the early stages. During the conversion process, Ge diffuses into the Si substrate and is mainly located near the SiC – Si interface with a concentration of around 2.5 – 3%. As a result of a complex alloying process promoted by interdiffusion of C and Ge as well as SiC nucleation, a thin 3C-SiC layer is formed on top of a Si1−xGex buffer layer. Copyright c � 2008 John Wiley & Sons, Ltd.