Method to reduce crystal defects particularly in group III-nitride layers and substrates

2 Gallium Nitride layers grown as single crystals by epitaxy such as Hydride Vapor Phase Epitaxy (HVPE) contain large numbers of crystal defects such as hexagonal pits, which limit the yield and performance of opto- and electronic devices. In this method, the Gallium Nitride layer is first coated with an Aluminum layer of approximate thickness of 0.1 microns. Next, Nitrogen is ion implanted through the Aluminum layer so as to occupy mostly the top 0.1 to 0.5 microns of the Gallium Nitride layer. Finally, through a pulsed directed energy beam such as electron or photons, with a fluence of approximately 1 Joule/cmthe top approximately 0.5 microns are converted to a single crystal with reduced defect density.