Tin-based donors in SiSn alloys

Abstract

Tin-containing Group IV alloys show great promise for a number of next-generation CMOS-compatible devices. Not least of those are optoelectronic devices such as lasers and light-emitting diodes. To obtain reliable operation, a high control over the doping in such materials is needed at all stages of device processing. In this paper, we report tin-based donors in silicon, which appear after heat treatment of a silicon-tin alloy at temperatures between 650 °C and 900 °C. Two stages of the donor are observed, called SD I and SD II, which are formed subsequently. A broad long-lifetime infrared photoluminescence is also observed during the first stages of donor formation. We discuss evolving tin clusters as the origin of both the observed donors and the photoluminescence, in analogy to the oxygen-based thermal donors in silicon and germanium.