Rectifying characteristics of WSi0.8–GaN Schottky barrier diodes with a GaN cap layer grown at low temperature

Undoped GaN/low-temperature (LT) GaN∕WSi0.8 and undoped GaN∕WSi0.8 Schottky barrier contacts were prepared. Introducing the LT GaN on top of the conventional structures markedly reduced the leakage current and increased the barrier height. The measured barrier heights of the LT GaN-caped samples and the conventional samples were around 1 and 0.55eV, respectively. The thermal stability of the Schottky barrier contacts was also studied and the barrier height was shown to be very stable even when the annealing temperature was increased to 950°C for 1h.