Observation of inductively coupled-plasma-induced damage on n-type GaN using deep-level transient spectroscopy

The effects of inductively coupled plasma (ICP) etching on electrical properties of n-type GaN Schottky contacts were investigated by observing ion damage using deep-level transient spectroscopy. An electron trap, not previously seen, localized near the contact, as well as a pre-existing trap, was observed in the ICP-etched sample. The ICP-etched surface was found to be N-deficient, which means that N vacancies (VN) were produced by ICP etching. From these, the origin of the ICP-induced electron trap was suggested to be VN or a VN-related complex of point defects. The ICP-induced traps provided a path for the transport of electrons, leading to the reduction of Schottky barrier height and increase of gate leakage current.