REVERSIBLE CHANGES IN DOPING OF INGAALN ALLOYS INDUCED BY ION-IMPLANTATION OR HYDROGENATION

Carrier concentrations in doped InN, In0.37Ga0.63N, and In0.75Al0.25N layers are reduced by both F+ ion implantation to produce resistive material for device isolation, and by exposure to a hydrogen plasma. In the former case, post-implant annealing at 450-500-degrees-C produces sheet resistances > 10(6) OMEGA/square in initially n+ (7 X 10(18)-3 X 10(19) cm-3) ternary layers and values of approximately 5 X 10(3) OMEGA/square in initially degenerately doped (4 X 10(20) cm-3) InN. The evolution of sheet resistance with post-implant annealing temperature is consistent with the introduction of deep acceptor states by the ion bombardment, and the subsequent removal of these states at temperatures less than or similar to 500-degrees-C where the initial carrier concentrations are restored. Hydrogenation of the nitrides at 200-degrees-C reduces the n-type doping levels by 1-2 orders of magnitude and suggests that unintentional carrier passivation occurring during cool down after epitaxial growth may play a role in determining the apparent doping efficiency in these materials.