IEEE Journal of the Electron Devices Society (Jan 2023)
Investigations on Wide-Gap Al<sub>0.21</sub>Ga<sub>0.79</sub>N Channel MOS-HFETs With In<sub>0.12</sub>Al<sub>0.76</sub>Ga<sub>0.12</sub>N Barrier/Buffer and Drain Field-Plate
Abstract
This work investigates, for the first time, wide-gap Al0.21Ga0.79N channel metal-oxide-semiconductor heterostructure field-effect transistors (MOS-HFETs) with In0.12Al0.76Ga0.12N barrier/buffer and drain field-plate (DFP) designs. High-k and wide-gap Al2O3 was grown as the gate oxide and surface passivation by using non-vacuum ultrasonic spray pyrolysis deposition (USPD) technique. A control device having the same epitaxial layers, except with In0.12Al0.88N barrier/buffer was studied in comparison. Enhanced spontaneous polarization effect, improved interfacial quality, and enhanced carrier confinement have been achieved by using the In0.12Al0.76Ga0.12N barrier/buffer design, which has successfully resulted in improved carrier transport, increased electron concentration, and high current densities. The present In0.12Al0.76Ga0.12N/AlN/Al0.21Ga0.79N MOS-HFET design with (without) DFP design has demonstrated superior maximum drain-source current density $(I_{DS, max})$ of >1 (>1) A/mm at $V_{DS}\,\,=$ 20 V, high saturated drain-source current density at $V_{GS}\,\,=$ 0 V $(I_{DSS0})$ of 791.1 (755) mA/mm, and low specific on-resistance $(R_{on, sp})$ of 2.83 (2.81) $\text{m}\Omega $ /cm 2. High device figure-of-merit (FOM) on $BV_{DS}^{2}/R_{on, sp}$ of 93.7 (75.4) MW/cm 2 was also obtained with the three-terminal on-state drain-source breakdown voltage $(BV_{DS})$ of 515 (460) V. The present design is promisingly advantageous to high-current and high-voltage power-switching circuit applications.
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