The effects of ion mass, energy, dose, flux and irradiation temperature on implantation disorder in GaN

The effects of implant conditions on the damage build-up in wurtzite GaN films are studied by Rutherford backscattering/channeling spectrometry and transmission electron microscopy. The results point to substantial dynamic annealing of radiation defects even during heavy ion (¹⁹⁷Au) bombardment at liquid nitrogen (LN₂) temperature. A marked similarity between damage build-up for light (¹²C) and heavy (¹⁹⁷Au) ion bombardment regimes at LN₂ temperature is observed. However, the damage build-up behavior during room temperature (RT) bombardment with ¹²C or ¹⁹⁷Au ions is different. Implantation temperature not only affects the gross level of implantation disorder but also controls the general behavior of damage build-up during light or heavy ion bombardment. For all implant conditions of this study, a band of planar defects nucleates and grows in the bulk with increasing ion dose. An increase in the energy of Au ions from 100 to 2000 keV does not change the main features of damage build-up at LN₂ temperature. The results also show that implantation disorder in GaN depends on beam flux.