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 situ and in real time using the low-energy electron microscope. The Ga flux was supplied by an evaporative cell while the ${\mathrm{NH}}_{\mathrm{3}}$ flux was supplied via a seeded-beam supersonic jet source. At growth temperatures of 665 °C and 677 °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 ${\mathrm{Ga/NH}}_{\mathrm{3}}$ flux ratios exceeded 2, starting with a Ga-covered substrate surface, in the temperature range of 655–710 °C.