Optimizing Back Barrier Material Composition and Thickness of Al0.15Ga0.85N/GaN/AlxGa1-xN MIS-HEMT Device Structure for High-Power Enhancement Mode Applications

In this work, we offer a thorough investigation into how the thickness and concentrations of Al, Ga material in the back barrier layer influence a single channel Double hetero structure Metal Insulator Semiconductor High Electron Mobility Transistor (DH-MIS-HEMT). The optimized thickness of the back barrier layer (BBL) helps to confine the electrons within the channel region, controls the threshold voltage of the device (V
T
), raises the conduction band resulting in low leakage current and improvement in breakdown voltage (V
BD
), increases the and sheet carrier density (n
s
) of the device. In this work, the thickness of the BBL is varied from 2 nm to 24 nm and mole concentration of Al, Ga in AlₓGaN
1-X
BBL is varied by fixing the values of x as 0.02, 0.04, 0.06, 0.08, and 0.10. The goal is to identify the optimal thickness and composition of Al, Ga materials in the DH MISHEMT device to ensure effective performance in high-power and fast switching applications along with optimized overall device efficiency. When the Al concentration in the BBL gets increased, the carrier concentration in the channel reduces due the increase in parasitic channel effect and this results in the reduction of drain current and transconductance (g
m
). The TCAD simulation results of the proposed DH-MIS-HEMT device structure results in I
D
of 0.72 A/mm, V
BD
of 938 V, g
m
of 0.263 S/mm and V
T
of 3.34 V for Al
0.08
Ga
0.92
N BBL with the thickness of 16 nm. The obtained results show that the optimal thickness and mole content of Ga and Al in BBL shows an enhancement in the V
BD
and DC characteristics that makes the device to support for high power handling and high-speed switching applications.