AlGaN/GaN HEMTs with an Insulated Gate Fabricated by Inductively Coupled Plasma Oxidization

Novel AlGaN/GaN high electron mobility transistors (HEMTs) with an insulated gate have been demonstrated by oxidizing the surface of an AlGaN layer using inductively coupled O₂ plasma. X-ray photoelectron spectroscopy measurement reveals that O₂ plasma treatment can produce a thin oxidized layer on the AlGaN surface. The insulated-gate devices are realized by plasma oxidization before gate metallization. The reverse gate leakage current of the fabricated HEMT has been reduced in two orders of magnitude, and the cut-off frequency increases from 5.4GHz to 6.5GHz.