A study was made of the structural characteristics of wurtzite-type material which had been bombarded with 197Au+ ions, at 550C, to a wide range of doses. The results showed that the build-up of disorder, and amorphization, were suppressed at high temperatures; as compared to the effects of implantation at room temperature or below. With increasing ion dose, evolution of the damage proceeded via the formation of point-defect complexes plus some planar defects, which were parallel to the basal plane of the film. However, high-dose bombardment at high temperatures was complicated by an anomalous surface erosion. Such erosion was attributed to a 3-step process: the accumulation of implantation disorder with increasing ion-dose, thermal and ion-induced decomposition of a heavily damaged near-surface layer and ion-stimulated erosion of such highly N-deficient layers.

Disordering and Anomalous Surface Erosion of GaN during Ion Bombardment at Elevated Temperatures. S.O.Kucheyev, J.S.Williams, J.Zou, C.Jagadish, G.Li: Applied Physics Letters, 2001, 78[10], 1373-5