Micro-Raman spectroscopy observation of field-induced strain relaxation in AlGaN/GaN heterojunction field-effect transistors

• Published in: Physica status solidi. A, Applications and materials science Vol. 209; no. 6; pp. 1174 - 1178
• Main Authors: Dun, Shaobo, Jiang, Yang, Li, Jingqiang, Fang, Yulong, Yin, Jiayun, Liu, Bo, Wang, Jingjing, Chen, Hong, Feng, Zhihong, Cai, Shujun
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.06.2012; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: AlGaN/GaN HFETs; inverse piezoelectric effect; micro-Raman; R&D; Research & development; Semiconductors; Spectrum analysis; strain relaxation
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201127553

A new method to characterize the strain status in the electrical degradation of AlGaN/GaN heterojunction field‐effect transistors (HFETs) using micro‐Raman spectroscopy at a wavelength of 532 nm was proposed. This method was applied to the devices stressed under different dc biased configurations to find the direct evidence of strain relaxation due to inverse piezoelectric effect (IPE). It was observed that the strain relaxation in AlGaN barrier layers became more severe with the increment of the electric field applied externally, which would lead to the rise of the gate leakage current. The deterioration of the gate leakage current shows a time‐dependent feature.