Ni and Ni suicide Schottky contacts on n-GaN

The electrical characteristics of Ni and NiSi Schottky diodes on n-GaN have been investigated as a function of annealing. Ni diodes were found to be stable up to 500 °C for 1 h in sequential annealing, with a barrier height Φ (I-V) of 0.8-0.9 eV and an n factor of ∼ 1.1. The barrier height deduced from C-V measurements, Φ (C-V), was typically 0.15 eV higher than Φ (I-V). At 600 °C the diodes failed, and Ga was found to migrate into the Ni layer. NiSi diodes were stable up to 600 °C for 1 h, Φ (I-V) was found to be about 0.8-1 eV with an n-factor of about 1.15, The value of Φ (C-V) was between 0.3 to 0.6 eV higher than Φ (I-V), consistent with the notion of the presence of a thin insulating layer at the NiSi/GaN interface. The electrical characteristics obtained in this study are also compared with those obtained for Pt and PtSi Schottky diodes on n-GaN.