Floating zone growth of Si-rich SiGe bulk crystal using pre-synthesized SiGe feed rod with uniform composition

Growth of SiGe bulk crystal was attempted by the floating zone (FZ) technique using high-power semiconductor lasers. SiGe feed rod with uniform composition was pre-synthesized from Si and Ge powders, and utilized as a source material for FZ growth. The Ge composition of the grown SiGe crystal was found to be smaller than that of the feed rod owing to the segregation phenomena especially during the initial stage of the growth. This reduction of Ge was shown to be avoidable by applying an appropriate artificial design of the composition in the feed rod. Low-temperature photoluminescence measurement clarified that the grown SiGe crystal exhibits well-resolved band-edge luminescence without any deep-level emissions.