Observation of Quasi-Saturation Phenomenon in Sidewall Gate GaN Vertical Transistors
Journal
ACS Applied Electronic Materials
Journal Volume
7
Journal Issue
19
Start Page
9030
End Page
9036
ISSN
26376113
Date Issued
2025-10-14
Author(s)
Chang, Chih-Kang
Zhang, Zhi-Xiang
Li, Ting-Ci
Wang, Jun-Xiang
Chu, Yu-Chuan
Wang, Ting-I
Wang, Tien-Yu
Lai, Wei-Chih
Huang, Jian-Jang
Abstract
We report the observation of quasi-saturation behavior in GaN vertical metal oxide semiconductor field-effect transistors featuring a sidewall-gate architecture. Compared to conventional trench-gate designs, the sidewall-gate structure exhibits pronounced drain current roll-off and negative transconductance under high gate bias. This degradation is consistent with space charge modulation, wherein localized electron accumulation at the gate-drift interface distorts the electric field distribution and limits carrier mobility. Comprehensive electrical characterization and technology computer-aided design simulations reveal how asymmetric gate geometry affects vertical and lateral electron spreading paths. These findings highlight the role for mitigating field-induced current degradation in vertical GaN power devices.
Subjects
current crowding
quasi-saturation
sidewall gate
space charge modulation
vertical GaN MOSFETs
Publisher
American Chemical Society
Type
journal article