High Voltage Normally-Off p-GaN Gate HEMT with the Compatible High Threshold and Drain Current

Abstract

In this paper, we demonstrate a high-voltage normally-off p-GaN gate high-electron-mobility-transistor (HEMT) to realize the compatible high threshold voltage (VTH) and high drain current (ID) performance. With the optimization of epitaxial structure, VTH is significantly improved in the presented device. Meanwhile, through using the high-quality ALD-Al2O3 passivation layer, the high ID is also realized in the device because of the reduction of the access region resistance. Supported by the device fabrication, the p-GaN gate HEMT delivers a VTH=3.2 V measured by linear extrapolation, a relatively large saturation ID (ID_SAT) of 246 mA/mm, and a high break-down voltage (BV) of 1830 V at 1 mA/mm. Among various p-GaN gate HEMTs with the ID_SAT over 200 mA/mm, the fabricated device has a competitive VTH. The results suggest that the pro-posed p-GaN gate HEMT could be a promising candidate in high VTH and ID power electronics.

Enhancement-mode GaN HEMT using a combination structure of recessed-gate and p-GaN gate structure

“…GaN-based high electron mobility transistors (HEMTs) have been widely used in the fields of high temperature, high frequency and high power due to the superior properties such as wide bandgap, high breakdown electric field, good thermal stability and high electron saturation velocity [1] . Different to Si and GaAs based electronic devices, high density two-dimensional electron gas (2DEG) channel can be formed by the large polarization discontinuity and conduction band offset between AlGaN (or InAlN) barrier and GaN channel layer even without intentional doping [2][3][4] . So, the conventional GaN-based HEMTs are normally-on (depletion-mode) devices.…”