Effects of NiO on electrical properties of NiAu-based ohmic contacts for p-type GaN

Publisher Website
Google Scholar
Abstract
Effects of a NiO layer on the electrical properties of NiAu-based ohmic contacts for p- GaN were studied by depositing a p-type NiO layer on the p- GaN using a sputter-deposition technique. NiO layers doped with Li[NiO(Li)] had a p-type conduction with sheet resistivity of around 1 Ω cm after annealing at temperatures lower than 500 °C. A variety of the NiAu-based contacts with the NiO layers such as NiO/Au, NiO(Li)/Au, Ni/NiO(Li)/Au, Ni/Li 2 O/NiO/Au , and Ni/Li 2 O/Ni/NiO/Au contacts were prepared by depositing on the p- GaN , where a slash “/” indicates the deposition sequence. However, these contacts did not provide specific contact resistances (ρ c ) lower than that (ρ c ∼10 −2 Ω cm 2 ) of the conventional Ni/Au contacts prepared by annealing in N 2 ambient. From the present results, it was believed that the p- NiO layer did not act as an intermediate semiconductor layer to reduce the Schottky barrier height at the p- GaN/Au interface.