In this work, AlGaN/GaN HEMTs with dual-layer SiNx stressors (composed of a low-stress layer and a high-stress layer) were investigated. The low-stress padding layer solved the surface damage problem caused during the deposition of the high-stress SiNx, and provided a good passivated interface. The HEMTs with dual-layer stressors showed a 1 V increase in the threshold voltage (Vth) with comparable on-current and RF current gain to those without stressors. Moreover, the off-current (I_off) was shown to be reduced by one to three orders of magnitude in the strained devices as a result of the lower electric field in AlGaN, which suppressed the gate injection current. The dual-layer stressor scheme supports strain engineering as an effective approach in the pursuit of the normally-off operation of AlGaN/GaN HEMTs.
@article{arxiv.1908.00125,
title = {Threshold Voltage Improvement and Leakage Reduction of AlGaN/GaN HEMTs Using Dual-Layer SiNx Stressors},
author = {Wei-Chih Cheng and Minghao He and Siqi Lei and Liang Wang and Jingyi Wu and Fanming Zeng and Qiaoyu Hu and Feng Zhao and Mansun Chan and Guangrui and Xia and Hongyu Yu},
journal= {arXiv preprint arXiv:1908.00125},
year = {2019}
}