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

The effects of implant conditions on the damage build-up in wurtzite GaN fi lms are studied by Rutherford backscattering/channeling spectrometry and tr ansmission electron microscopy, The results point to substantial dynamic an nealing of radiation defects even during heavy ion (Au-197) bombardment at liquid nitrogen (LN2) temperature. A marked similarity between damage build -up for light (C-12) and heavy (Au-197) ion bombardment regimes at LN2 temp erature is observed. However, the damage build-up behavior during room temp erature (RT) bombardment with C-12 or Au-197 ions is different. Implantatio n temperature not only affects the gross level of implantation disorder but also controls the general behavior of damage build-up during light or heav y ion bombardment. For all implant conditions of this study, a band of plan ar defects nucleates and grows in the bulk with increasing ion dose. An inc rease in the energy of Au ions from 100 to 2000 keV does not change the mai n features of damage build-up at LN2 temperature. The results also show tha t implantation disorder in GaN depends on beam flux. (C) 2001 Elsevier Scie nce B,V. Ail rights reserved.