Growth of GaN films with low oxygen concentration using Ga2O vapor and NH3

Abstract In this study, we investigated the relationship between surface morphology and oxygen concentration in GaN layers synthesized from Ga 2 O vapor and NH 3 . The surface morphology of GaN layers changed from rough (with large numbers of pits) to (0 0 0 1) smooth planes with the increase in NH 3 concentration. SIMS mapping analysis revealed that the oxygen concentration was on the order of 10 17  atoms/cm 3 , the lowest level obtained in GaN layers synthesized from Ga 2 O vapor and NH 3 , at the smooth (0 0 0 1) surfaces. By contrast, high oxygen concentration over 10 20  atoms/cm 3 was detected at the pitted areas. We concluded that GaN films with low oxygen contamination can be obtained by suppressing pit formation and promoting the smoothness of the (0 0 0 1) surface, even when using Ga 2 O as the Ga source.