Transmission electron microscopy investigation of the structural damage formed in GaN by medium range energy rare earth ion implantation

The crystallographic nature of the damage created in GaN by 300 keV rare earth ions has been investigated following implantation at room temperature by varying the fluence of Er, Eu, or Tm from 7 × 10 13 to 2 × 10 16 at. ∕ cm 2 . There is a build up of point defects clusters, which increases in density and depth versus the ion fluence. When a threshold around 3 × 10 15 at. ∕ cm 2 is reached, a nanocrystalline surface layer is observed. From the lowest fluence, we point out the formation of basal stacking faults, with a majority of I 1 . Their density also increases with the fluence, but it is seen to saturate at the onset of the observation of the surface nanocrystalline layer. Extrinsic E faults bounded by the c ∕ 2 partials have also been identified; however, most of the E stacking faults transform to I 1 which are noticed to fold easily from basal to prismatic planes by switching or not to the Drum atomic configuration.