Germanium Photodetectors for Silicon Microphotonics by Direct Epitaxy on Silicon

Abstract

AbstractWe have grown high-quality Ge epilayers on Si using two-step ultrahigh vacuum/chemical-vapor-deposition followed by post-growth cyclic thermal annealing. Cyclic annealing was effective in reducing threading dislocation densities. The annealing process was improved by optimizing the dislocation velocity. We fabricated and tested metal-semiconductor-metal planar photodetectors using Ge epilayers grown on Si. Our measurement showed an improvement in the photodetector performance as a result of the improved materials quality. The process described in this paper for making high-quality Ge on Si is uncomplicated and can be easily integrated with Si CMOS processes.