Effect of H2 carrier gas on the physical properties of a GaN layer grown using Ga2O vapor and NH3

We investigated the effect of H2 ratio in carrier gas on oxygen concentration, crystallinity and threading dislocation density (TDD) in GaN layers synthesized from Ga2O vapor and NH3. SIMS analysis revealed that the oxygen concentration in GaN layers decreased with increasing H2 ratios, and achieved 8.72×1017 atoms/cc with a growth rate of 50 μm/h when the H2 ratio was 80%. The full width at half maximum (FWHM) and TDD decreased with increasing H2 ratios. To explain these results, we explored the growth mode at the initial growth stage in H2 ambient, and found that the nucleation rate of the GaN crystal decreased in H2 ambient, resulting in the improvement of crystallinity.