Model Development for Threshold Voltage Stability Dependent on High Temperature Operations in Wide-Bandgap GaN-Based HEMT Power Devices.

Huolin Huang,Yaqing Cao,Zhonghao Sun,Feiyu Li

doi:10.3390/mi9120658

Huolin Huang, Yaqing Cao + Show 2 more

Open Access

https://doi.org/10.3390/mi9120658

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Journal: Micromachines	Publication Date: Dec 14, 2018
Citations: 13	License type: CC BY 4.0

Affiliation: Dalian University, Dalian University of Technology

Abstract

Temperature-dependent threshold voltage (Vth) stability is a significant issue in the practical application of semi-conductor power devices, especially when they are undergoing a repeated high-temperature operation condition. The Vth analytical model and its stability are dependent on high-temperature operations in wide-bandgap gallium nitride (GaN)-based high electron mobility transistor (HEMT) devices that were investigated in this work. The temperature effects on the physical parameters—such as barrier height, conduction band, and polarization charge—were analysed to understand the mechanism of Vth stability. The Vth analytical model under high-temperature operation was then proposed and developed to study the measurement temperatures and repeated rounds dependent on Vth stability. The validity of the model was verified by comparing the theoretical calculation data with the experimental measurement and technology computer-aided design (TCAD) simulation results. This work provides an effective theoretical reference on the Vth stability of power devices in practical, high-temperature applications.

Highlights

Gallium nitride (GaN)-based high electron mobility transistors (HEMTs) have demonstrated a great potential in the fields of power electronics, mainly owing to their large semi-conductor bandgap (~3.4 eV), low intrinsic carrier concentration, and high-density two dimensional electron gas (2DEG) (>1013 cm−2), along with their high electron mobility (>2000 cm2·V·s−1) at the AlGaN/gallium nitride (GaN) heterojunction interface [1,2,3]
GaN-based HEMTs with a selected short gate length have overcome laterally diffused metal oxide semiconductor (LDMOS)-based transistors for the applications above the L-band owing to their higher frequency capabilities
This paper systematically investigates the Vth analytical model and the stability mechanism when subjected to the different measurement temperatures and repeated rounds in GaN-based HEMTs

Summary

Introduction

Gallium nitride (GaN)-based high electron mobility transistors (HEMTs) have demonstrated a great potential in the fields of power electronics, mainly owing to their large semi-conductor bandgap (~3.4 eV), low intrinsic carrier concentration, and high-density two dimensional electron gas (2DEG) (>1013 cm−2), along with their high electron mobility (>2000 cm2·V·s−1) at the AlGaN/GaN heterojunction interface [1,2,3]. This paper systematically investigates the Vth analytical model and the stability mechanism when subjected to the different measurement temperatures and repeated rounds in GaN-based HEMTs. Considering that a relatively large gate length of 2 μm was employed in the fabricated devices, the direct current (DC) characteristics are analysed in this work. The effects of the high temperature on the physical parameters, such as barrier height, conduction band, Fermi level, polarization charge, and interface traps were analysed to understand the Vth stability mechanism. Both the experimental measurement of the device and technology computer-aided design (TCAD) simulation work were carried out and the validity of the model was verified. IGS and VGS are the gate-to-source current and voltage, a is the gate contact area, and A* (= 28.4 A·cm−2·K−2) is the effective Richardson constant

Conduction Band Offset

Polarization Charge

Conclusions