Changes in surface chemical structure of BF$_{3}$ plasma doped Si$_{0.7}$Ge$_{0.3}$ films

Ultra shallow junctions were formed using BF$_{3}$ plasma doping process in Si$_{0.7}$Ge$_{0.3}$ films. The damaged Si$_{\mathrm{x}}$Ge$_{\mathrm{y}}$ layer of a few {\AA} was observed in near surface region of doped Si$_{0.7}$Ge$_{0.3}$ films, which increased especially the interfacial germanium oxide states. While the surface oxide layer of as-grown Si$_{0.7}$Ge$_{0.3}$ film was mainly composed of silicon oxide, the oxide layers of doped Si$_{0.7}$Ge$_{0.3}$ films were largely composed of germanium oxide. It is reported that the interfacial GeO$_{\mathrm{2-x}}$ states are related with the interfacial defect states. In the doped films, however, GeO$_{\mathrm{2-x}}$ states were decreased after rapid thermal annealing (RTA) process. In especially, after RTA of doped sample with process conditions of 300 W and 30 s, it is shown that the formation of interfacial defect states were significantly decreased, which was caused by the Ge-F bond generated on the SiGe surface.