Effect of reactive ion etching-induced defects on the surface band bending of heavily Mg-doped p-type GaN

The effect of reactive ion etching-induced defects on the surface band bending of heavily Mg-doped p-type GaN (p-GaN) was investigated in this study. According to the observed results from x-ray photoelectron spectroscopy and secondary-ion-mass spectroscopy (SIMS) measurements, we found that the formation of more nitrogen-vacancy-related defects created near the surface by reactive ion etching technique would lead to an increase in the surface band bending, a shift of the surface Fermi level toward the conduction-band edge, the reduction of the current flow at the metal∕etched p-GaN interface, and an increase in the barrier height at the metal∕etched p-GaN interface. In addition, from the SIMS measurements, it is suggested that the depth of the nitrogen-deficient near-surface region resulting from the dry-etch process is about 60nm.