Threshold Voltage Analysis of E-mode Recessed p-GaN Gate HEMT-A Simulation Based Study

Abstract

In power-electronics applications or switching applications Normally-off AlGaN/GaN high electron mobility transistors (HEMTs) are needed with higher threshold voltage ($\mathrm{V}_{\mathrm{t}\mathrm{h}}$) and high drain current (Id). Previously a lot of experiments have been done to propose emode HEMT structures by using several gate engineering techniques like recessed metal-gate HEMT, p-GaN gate HEMT and thin-barrier layer HEMT etc. This paper depicts a unique enhancement-mode recessed p-GaN gate HEMT structure with incorporating recess gate (p-GaN) engineering techniques which have unique advantages of all above proposed structures. Proposed results got up to 2. 7V of threshold voltage and by analyzing the band diagram, it is also observed that the triangular well at AlGaN/GaN interface is uplifted to 2. 54eV from the Fermi-level, which is significantly higher than p-GaN gate HEMT (only 0. 42SeV from the Fermi level). The proposed HEMT structure is simulated in Silvaco Atlas software version 5. 0.22.R by changing the parameters like x-mole fraction of the barrier layer, recess depth ($\mathrm{R}_{\mathrm{d}}$), and doping concentration of p-GaN layer (NA). The trans-conductance graph is generated by Tony-plot tool available in the software.