Annealing of ion-implanted GaN

(111m)Cd and (112)Cd ions have been implanted into GaN. With photoluminescence spectroscopy and perturbed gamma gamma angular correlation spectroscopy (PAC) the reduction of implantation damage and the optical activation of the implants have been observed as a function of annealing temperature using different annealing methods. The use of N(2) or NH(3) atmosphere during annealing allows temperatures up to 1323 and 1373 K, respectively, but above 1200 K a strong loss of Cd from the GaN has been observed. Annealing GaN together with elementary Al forms a protective layer on the GaN surface allowing annealing temperatures up to 1570 K for 10 min. (C) 1999 Elsevier Science B.V. All rights reserved.