Abstract
As development of semiconductor industry, monolithic integration of silicon and other semiconductor devices is attracting significant interest. For optical interconnects to silicon chips, germanium-tin (GeSn) alloy is one of the most promising solutions due to its beneficial properties, such as the potential to become direct bandgap and compatibility with CMOS technology. Conventionally, GeSn alloy is grown by molecular beam epitaxy (MBE). However, thermal budget problem in epitaxy diminishes the compatibility with integrated circuits (ICs). Rapid melt growth (RMG) is a good processing method to realize hetero-integration with small thermal budget. By using RMG method, we successfully fabricate single-crystalline GeSn waveguide photodetectors on a SOI wafer with high-efficiency optical coupling. Due to tin-alloying, the detection wavelength of GeSn photodetectors is extended to 2000nm. Metal-semiconductor-metal (MSM) devices have the advantages of simple process and high-speed response. GeSn MSM photodetector fabricated by RMG is featured with simple process, low cost, high crystallinity, small thermal budget, good compatibility and high bandwidth.