Homogeneity evaluation of Mg implanted GaN layer by on-wafer forward diode current mapping

Ion implantation is a widely used doping technique for Si MOSFETs, but there have been few reports that demonstrate the formation of p-type GaN layer. We have succeeded to make the p-n junction by implanting Mg ions into n-type GaN layer, but Mg implanted layer showed inhomogeneity including p and n-type regions. Evaluation methods of homogeneity of Mg ion implanted GaN layer by mapping technique using current-voltage characteristics are demonstrated. •Mg ion implanted layer on GaN substrate showed inhomogeneity including p and n-type regions.•New mapping method of IV characteristics was developed to determine p- or n-type regions in the layer w/o Ohmic contacts.•Mg ion implanted layer has an almost homogeneous p-type behavior, however, it contains small areas with n-type character.