Study On The Initial Growth Stage Of Device-Quality Cubic Gan On (001) Gaas By Rheed And Afm: The Nitridation And Buffer-Layer Deposition Processes In Mbe

Growth of high-quality cubic GaN (c-GaN) layers on GaAs has been investigated by an rf-radical source MBE in terms of nitridation of the substrate and buffer layer deposition at initial growth stage. The nitridation of the (001) GaAs surface at 620 degrees C resulted in the formation of c-GaN with rough surface. In order to obtain flat surface of c-GaN, we have examined the nitridation process at low temperature. It was found that the nitridation of GaAs surface at 500 degrees C was suitable, because the reaction of Ga with N was slow enough to form c-GaN uniformly and the surface was kept flat even after the nitridation.