Performance Analysis of an Enhancement Mode Operated AlGaN/GaN MIS-HEMT Device with Ga2O3 as a Back Barrier

Rapid technological advancements over the past decade have propelled gallium oxide to the forefront of ultra-wide bandgap semiconductor technologies, owing to its favorable intrinsic material properties. In this work, we propose an enhancement mode-operated recessed gate AlGaN MIS-HEMT device structure with Ga
2
O
3
as a back barrier. Ga
2
O
3
’s wide bandgap reduces trapping states near the semiconductor interface, improving carrier transport and leading to increased saturation current and transconductance. The use of a β-Ga
2
O
3
back-barrier layer in the device creates a potential well that enhances carrier concentration and improves electron mobility, resulting in higher sheet charge density. In this work, we compared a MIS-HEMT device featuring a Ga
2
O
3
back barrier with a conventional MIS-HEMT structure with AlGaN as the back barrier and analyze the DC and RF characteristics. Numerical results of the proposed Al
0.15
Ga
0.85
N/GaN/Ga
2
O
3
obtained from TCAD simulations show that an
$\mathrm{I}_{\text{ds}}$
of 0.84 A/mm,
$V_{B D}$
of 1012 V, R
ON
of 6.45 ohm.mm,
$\mathrm{f}_{\mathrm{t}}$
of 34 GHz,
$\mathrm{f}_{\max}$
of 84 GHz,
$\mathrm{g}_{\mathrm{m}}$
of 0.25 S/mm and
$\mathrm{V}_{\text{TH}}$
of 3.02 V is obtained. The results obtained indicate that incorporating Ga
2
O
3
as a back barrier, optimizing layer thickness, and employing a recessed gate structure collectively improve the DC and RF characteristics of the device, rendering it suitable for high-frequency and high-power applications.