Growth of GaN films with low oxygen concentration using Ga sub(2)O vapor and NH sub(3)

In this study, we investigated the relationship between surface morphology and oxygen concentration in GaN layers synthesized from Ga sub(2)O vapor and NH sub(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 sub(3) concentration. SIMS mapping analysis revealed that the oxygen concentration was on the order of 10 super(17) atoms/cm super(3), the lowest level obtained in GaN layers synthesized from Ga sub(2)O vapor and NH sub(3), at the smooth (0 0 0 1) surfaces. By contrast, high oxygen concentration over 10 super(20) atoms/cm super(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 sub(2)O as the Ga source.