Silicon Minority-carrier Lifetime Degradation during Molecular Beam Heteroepitaxial III-V Material Growth

A major hindrance to the development of devices integrating III-V materials on silicon, where it is an active component of the device, is the preservation of its electronic quality. In this contribution, we report on our effort to identify the mechanism behind the severe decrease in the bulk minority-carrier lifetime of silicon after heteroepitaxial growth of gallium phosphide, in our molecular beam epitaxy (MBE) system. We identify that the drop in lifetime occurs at a threshold temperature of 500 °C; we assign the increased recombination rate to extrinsic, fast-diffusing impurities coming from the MBE chamber environment. Impurities can be gettered by phosphorous diffusion, leading to a lifetime recovery. Moreover, we narrow the list of contaminants based on specific experimental observations and compare our hypothesis to modeling of injection-dependent lifetime spectra. Finally we show that coating the silicon wafer with a sacrificial silicon nitride film helps significantly to reduce contamination and provides a path to successful III-V growth on silicon.