The Current Collapse in AlGaN/GaN High-Electron Mobility Transistors Can Originate from the Energy Relaxation of Channel Electrons?

Ling-Feng Mao,Jin-Yan Wang,Huan-Sheng Ning

doi:10.1371/journal.pone.0128438

Abstract

Influence of the energy relaxation of the channel electrons on the performance of AlGaN/GaN high-electron mobility transistors (HEMTs) has been investigated using self-consistent solution to the coupled Schrödinger equation and Poisson equation. The first quantized energy level in the inversion layer rises and the average channel electron density decreases when the channel electric field increases from 20 kV/cm to 120 kV/cm. This research also demonstrates that the energy relaxation of the channel electrons can lead to current collapse and suggests that the energy relaxation should be considered in modeling the performance of AlGaN/GaN HEMTs such as, the gate leakage current, threshold voltage, source-drain current, capacitance-voltage curve, etc.

Highlights

The AlGaN/GaN high-electron mobility transistor as a promising technology has recently emerged in the application of switch and radio frequency electronics
Using the mobility and the energy relaxation time reported in the Table III in Ref. [21], the obtained electrontemperature and the channel electric field satisfy an exponential relation
In other words, when source-drain current saturates at a given channel electric field with a constant voltage applied to the gate, the decrease in the channel electron density caused by the increase in the channel electric field (which is described by the term r(Vg,VD) introduced in Eq 6 and Fig 4 clearly show that a larger channel electric field a smaller r(Vg,VD)) can lead to a decrease in the saturation current that is described as the current collapse phenomenon

Summary

Introduction

The AlGaN/GaN high-electron mobility transistor as a promising technology has recently emerged in the application of switch and radio frequency electronics. It shows that the peak of the channel electron density increases when the channel electric field increases, and the peak shift toward the AlGaN/GaN interface.

Results

Conclusion