Annealing study of ion implanted GaN

Ca is a potential shallow acceptor in GaN and was used for p-type doping in this study. Ca+ implantation with an energy of 180 keV was carried out in a dose range between 5 x 10(13) and 7.3 x 10(16) cm(-2) at room temperature. After implantation, rapid thermal annealing at 950-1150 degrees C for 15-60 s in flowing N-2 was performed to remove damage and to activate the dopants. The implantation-induced damage, the surface morphology and stoichiometry of the implanted film before and after annealing were studied by Rutherford backscattering/channeling, atomic force microscopy and Auger electron spectroscopy, respectively. The dependence of the damage build-up and removal on ion dose and annealing temperature was quantitatively analyzed. The duration of 30 s at 1150 degrees C has been shown to be the best annealing time. Surface degeneration of the implanted GaN after rapid thermal annealing at 1150 degrees C for 15-60 s was observed. (C) 2000 Published by Elsevier Science S.A. All rights reserved.