Ion Implantation and Annealing Studies in III–V Nitrides

ABSTRACTIon implantation doping and isolation is expected to play an enabling role for the realization of advanced Ill-Nitride based devices. In fact, implantation has already been used to demonstrate n- and p-type doping of GaN with Si and Mg or Ca, respectively, as well as to fabricate the first GaN junction field effect transistor.1-4 Although these initial implantation studies demonstrated the feasibility of this technique for the Ill-Nitride materials, further work is needed to realize its full potential.After reviewing some of the initial studies in this field, we present new results for improved annealing sequences and defect studies in GaN. First, sputtered A1N is shown by electrical characterization of Schottky and Ohmic contacts to be an effective encapsulant of GaN during the 1100 °C implant activation anneal. The A1N suppresses N-loss from the GaN surface and the formation of a degenerate n+-surface region that would prohibit Schottky barrier formation after the implant activation anneal. Second, we examine the nature of the defect generation and annealing sequence following implantation using both Rutherford Backscattering (RBS) and Hall characterization. We show that for a Si-dose of l × l016 cm-2 50% electrical donor activation is achieved despite a significant amount of residual implantation-induced damage in the material.