Plasma-induced damage to n-type GaN has been studied by atomic force microscopy and Raman spectroscopy. It was found that the extent of surface roughening is largely dependent on the surface defect density, since preferential sputtering at these sites takes place. Several Raman defect modes have emerged from the plasma-damaged samples, and have been compared to the defect modes observed from ion-implanted GaN. The defect peaks centered at 300 and 360 cm~(-1) have been assigned to disorder-activated Raman scattering modes, while the 453 and 639 cm~(-1) peaks have been attributed to vacancy scattering. It has also been demonstrated that structural damage can be annealed out at 900℃ for 60 s in flowing N_(2).
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