2015 Volume 4 Issue 2 Pages 109-114
Ni thin film (～20 nm) was uniformly formed on p-GaN substrates by radio frequency magnetron sputter deposition method. In order to improve the conductivity and electrical contact properties of Mg-doped p-GaN, the enhancement of H release from Mg-doped p-GaN was attempted by applying current flow through the substrates during low temperature annealing at 573 K and 673 K. The microstructure and electrical properties after the annealing were then analyzed by transmission electron microscopy observation, direct current conduction tests and Hall effect measurement tests. The results reveal that no reactions occur at the interface between deposited Ni film and p-GaN substrate during annealing at 573 K for 3600 s. The electrical conductivity of p-GaN shows higher improvement by applying current flow during annealing at 573 K and 673 K, compared to annealing without the current flow. To investigate the effect of applying current flow during annealing, the current values of the samples during annealing with and without applying current flow were measured and they were compared. The mechanism of H release from p-GaN by applying current flow during annealing were discussed.
