Ni/Au ohmic contacts to p-type N-doped ZnO

Abstract

The authors fabricated low-resistivity Ni/Au ohmic contacts on N-doped p-type ZnO films using electron-beam evaporation and the transmission line model technique. Both as-deposited and thermally annealed contacts showed ohmic conduction, and the specific contact resistivity decreased with the increase of annealing temperature. The lowest specific contact resistivity of 2.06× 10-4 cm2 was achieved after annealing at 600°C. Secondary ion mass spectroscopy indicated that activation of nitrogen acceptors and the interdiffusion at the metal/ZnO interface after annealing were accounted for by the improvement of ohmic conduction. The results also showed that the fabricated contacts were thermally stable. © 2008 The Electrochemical Society.