Effects of surface treatment and annealing for Au/Ni/n-GaN Schottky barrier diodes

Abstract

We report the basic electrical characteristics and uniformity of 25 Au/Ni Schottky barrier diodes (SBDs) with three different surface treatments ((I) no treatment (as-grown), (II) alkaline solution, and (III) HCl related solution) before and after post-metallization annealing at 400 °C. The SBDs with (II) showed small diode-to-diode variation in the Schottky barrier height and the ideality factor, and good uniformity over the electrode. In addition, after the annealing, the reverse-biased current significantly reduced to the prediction by the thermionic field emission model. Similar characteristics were obtained for the SBDs with (I), however, the uniformity over the electrode became worse after the annealing. For the SBDs with (III), the diode-to-diode variation was originally large, and the reverse-biased current did not significantly reduce. In addition, inhomogeneity with a line-shape pattern was observed in some SBDs with the large reverse-biased current. Residual Cl atoms may be responsible for low-barrier nature.