Quality improvement of metalorganic chemical vapor deposition grown GaP on Si by AsH3 preflow

GaP epilayers are grown on Si substrates after AsH3 preflow. Electron beam induced current observation and double-crystal x-ray diffraction show that the AsH3 preflow drastically improves crystalline quality of GaP epilayers. The full width at half-maximum of the (400) reflection obtained from 4.8 μm GaP is as small as 115 arcseconds. Secondary ion mass spectroscopy shows that As atoms accumulate at the GaP/Si interfaces, playing an important role in preventing Si outdiffusion into the GaP epilayers.