Novel Gyrotron Beam Annealing Method for Mg-Implanted Bulk GaN.

Here we present for the first time the use of gyrotron beam for selective annealing/activation of implanted Mg in bulk GaN films. Samples with 1 μm uGaN epi-Iayer grown by MOCVD on HVPE bulk n+GaN substrates were implanted with Mg (1 x 1019 cm−3) to a target depth of 500 nm. A systematic investigation of annealing temperature, N 2 overpressure, surface capping layer, and sample orientation to the beam are presented. Post-implantation, volumetric lattice deformation was recovered by performing continuous annealing at temperatures $>$ 1100 °C for 30 s. Both AIN capped and uncapped samples were studied. It is shown that the surface of uncapped GaN samples which were annealed at 1100 °C in 40 bar N 2 overpressure remained intact. Photoluminescence spectroscopy was performed and confirmed the incorporation of Mg in substitutional sites with this technique, along with formation of large density of nitrogen vacancy defects.