Loading Effect of Selective Epitaxial Growth of Silicon Germanium in Submicrometer-Scale Silicon (001) Windows

摘要

We report different loading effects in selective epitaxial deposition of silicon germanium on silicon (001) using different silicon sources, such as silane or dichlorosilane, and other conventional sources, such as germane, and hydrogen chloride in hydrogen carrier gas, in a low-pressure chemical vapor deposition system. Silane leads to lower relative deposition rates in a smaller silicon area, while dichlorosilane shows the opposite trend. Flowing silane and dichlorosilane simultaneously during deposition results in a similar deposition rate independent of exposed silicon area. Decreasing hydrogen chloride partial pressure is found to improve the loading effect for both the silane- and dichlorosilane-based process for a small active window of about 0.01 mu m(2). The results point to the importance of availability of the adsorbed species on the active silicon windows when their size is below 0.04 mu m(2).