RF Performance Analysis of Conventional and Recessed Gate AlGaN/GaN MOSHEMT using β–Ga2O3 as Dielectric Layer

In this research paper, a novel heterostructure AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor (MOSHEMT) is proposed, using an ultra-wide bandgap Oxide $\mathrm{Gallium}(\mathrm{O}_{-2}\mathrm{Ga}_{2}\mathrm{O}_{3})$ as dielectric layer growth on GaN substrate. The transfer and RF characteristics of the developed device with a recessed T-gate are compared with a conventional T-gate structure by using a two-dimensional (2D) simulation of the TCAD Silvaco Software at $300\mathrm{~K}$. A positive value of the threshold voltage VTH of $0.56\mathrm{~V}$ and the highest peak transconductance $\left(G_{\mathrm{m},\mathrm{max}}\right)$ of $1.15\mathrm{~S}/\mu\mathrm{m}$ were achieved for $2\mathrm{~nm}$ recess gate depth. A very small sub-threshold slope of $66\mathrm{mV}/$ dec was reached. The microwave frequency performances of this device showed an outstanding result. The E-mode device exhibited a cut-off frequency $(F_{t})$ of 49GHz, and a maximum frequency $(F_{\max})$ of 60GHz while the MOSHEMT with conventional gate structure attained to only 38GHz and 47GHz respectively. The simulation results make this improved AlGaN/GaN MOSHEMT using a β–Ga2O3 as a dielectric layer suitable for high-frequency electronic applications.