Quadruple Gate-Embedded T Structured GaN-Based Metal–Oxide–Semiconductor High-Electron Mobility Transistors

Abstract

In this paper, high performance quadruple gate-embedded T structured GaN-based metal–oxide–semiconductor high-electron mobility transistors (MOSHEMTs) were fabricated using laser interference photolithography method and photoelectrochemical oxidation method, in which polymethylmethacrylate was used as sacrificial layer. The associated drain-source saturation current was improved to 175 mA/mm and the gate leakage current at the gate-source voltage of −80 V was improved to $0.81~\mu \text{A}$ compared with the 125 mA/mm and $7.6~\mu \text{A}$ of the conventional single gate GaN-based MOSHEMTs, respectively. Moreover, the associated maximum extrinsic transconductance of the quadruple gate-embedded T structured GaN-based MOSHEMTs was enhanced from 97.3 mS/mm to 118.4 mS/mm. Besides, the associated unit gain cutoff frequency and the associated maximum oscillation frequency were improved from 7.6 GHz to 10.8 GHz and from 11.4 GHz to 27.4 GHz, respectively. The improved performances of the quadruple gate-embedded T structure GaN-based MOSHEMTs were attributed to the function of the gate length reduction and the gate resistance decrease.