AlGaN/GaN Recessed MIS-Gate HFET With High-Threshold-Voltage Normally-Off Operation for Power Electronics Applications

This letter reports normally-off operation of an AlGaN/GaN recessed MIS-gate heterostructure field-effect transistor with a high threshold voltage. The GaN-based recessed MIS-gate structure in conjunction with negative polarization charges under the gate allows us to achieve the high threshold voltage, whereas the low on-state resistance is maintained by the 2-D electron gas remaining in the channel except for the recessed MIS-gate region. The fabricated device exhibits a threshold voltage as high as 5.2 V with a maximum field-effect mobility of 120 cm²/Vmiddots, a maximum drain current of over 200 mA/mm, and a breakdown voltage of 400 V.