Novel high voltage RESURF AlGaN/GaN HEMT with charged buffer layer

Abstract

A novel reduced surface field (RESURF) AlGaN/GaN high electron mobility transistor (HEMT) with charged buffer layer is proposed. Its breakdown mechanism and on-state characteristics are investigated. The HEMT features buried Fluorine ions in the GaN buffer layer both under the Drift and the Gate region (FDG). The section of FDG under the drift region (FD) not only reduces the electric field (E-field) peak at the gate edge but also enhances the E-field in the drift region by the assisted depletion, leading to a significant improvement in breakdown voltage (BV). moreover, the section of FDG under the gate (FG) enhances the back barrier and effectively prevents electron injecting from the source to form leakage current, thus a higher BV is achieved. The BV of the proposed HEMT sharply increases to 750 V from 230 V of conventional AlGaN/GaN HEMT with the same dimensional parameters, and the specific on-resistance ($R_{\rm on,sp})$ just increases to \linebreak 1.21 m$\Omega \cdot $cm$^{2}$ from 1.01 m$\Omega \cdot $cm$^{2}$.