DEEP-LEVEL DEFECTS AND N-TYPE-CARRIER CONCENTRATION IN NITROGEN-IMPLANTED GAN

We analyzed the intrinsic defects and the n-type-carrier concentration generated by nitrogen ion implantation in n-type GaN by deep-level-tr ansient spectroscopy and by capacitance-voltage measurements, respecti vely. The samples were grown on sapphire by metalorganic vapor-phase e pitaxy. Nitrogen implantation with different ion doses and postimplant ation rapid-thermal annealing (RTA) were investigated. We observed a g rowing n-type-carrier concentration and increasing defect concentratio n with increasing nitrogen ion implantation doses. After RTA the conce ntration of free carriers and deep levels as found in the as-grown sta te are restored. We also address contrarily seeming results from measu rements of sheet resistance after N implantation published recently. ( C) 1996 American Institute of Physics.