Reduced gate leakage current in AlGaN/GaN HEMT by oxygen passivation of AlGaN surface

A remarkable reduction of the gate leakage current for AlGaN/GaN high electron mobility transistors (HEMT) is reported. The oxygen plasma treatment of the fabricated HEMT at 200degC reduced the gate leakage current by four orders of magnitude without degrading the transconductance and the drain current characteristics of the HEMT. X-ray photoelectron spectroscopy analysis showed that the binding of oxygen at the AlGaN surface is related to the reduction in the leakage current.