High Breakdown Electric Field MIS-Free Fully Recessed-Gate Normally Off AlGaN/GaN HEMT With N2O Plasma Treatment

In this article, the AlGaN barrier fully removed recessed-gate normally off AlGaN/GaN high electron mobility transistors (HEMTs) with N
₂
O plasma treatment are fabricated. The low speed and low damage etching is used in recessed-gate etching, the etching depth is about 26 nm with 0.4 nm remaining, and then, the remaining barrier layer is oxidized by N
₂
O plasma treatment. In the terms of devices' characteristics, the threshold voltage of the recessed-gate HEMT is +1.5 V, and the channel current of recessed-gate HEMTs at V
_GS
- V
_TH
= 1.5 V is about 110 mA/mm. Moreover, 14 mV/V of drain-induced barrier lowering (DIBL) and 70 mV/decade of subthreshold slope (SS) are achieved. More importantly, the fully recessed-gate HEMT shows the average breakdown electric field at V
_G
= 0 V of about 0.64 MV/cm, which is a very high value in the fully normally off recessed-gate HEMTs without metal insulator semiconductor (MIS) structure, which will be beneficial to the application of this device in the low power supply topology circuit.