Study of the Surface Cleaning of GOI and SGOI Substrates for Ge Epitaxial Growth

An effective wet cleaning process, optimized for low temperature Ge epitaxy on thin Ge or SiGe structures with reduced surface roughening, is proposed. It is found that the HF+HCl cleaning is the most effective wet cleaning method that is applicable to the low temperature thermal cleaning. It is also found that temperature of the thermal cleaning appropriate for thin Germanium on Insulator (GOI) substrates is approximately 450oC. Moreover, the successful formation of the strained-GOI structures is demonstrated by applying these wet and thermal cleaning processes to thin Silicon-Germanium on Insulator (SGOI) substrates.