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 200°C 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.