Low-energy electron microscopy observations of GaN homoepitaxy using a supersonic jet source

A study of the homoepitaxial growth of GaN(0001) layers was conducted in si tu and in real time using the low-energy electron microscope. The Ga flux w as supplied by an evaporative cell while the NH3 flux was supplied via a se eded-beam supersonic jet source. At growth temperatures of 665 degrees C an d 677 degrees C, smooth GaN(0001) layers with well-defined step structures were grown on GaN(0001) substrates prepared by metalorganic chemical vapor deposition. In general, nonfaceted homoepitaxial layers were achieved when the Ga/NH3 flux ratios exceeded 2, starting with a Ga-covered substrate sur face, in the temperature range of 655-710 degrees C. (C) 1999 American Inst itute of Physics. [S0003-6951(99)04533-7].