中国物理B ›› 2022, Vol. 31 ›› Issue (11): 117105-117105.doi: 10.1088/1674-1056/ac81a6
Zhihong Chen(陈治宏)1, Minhan Mi(宓珉瀚)1,3,†, Jielong Liu(刘捷龙)2, Pengfei Wang(王鹏飞)1, Yuwei Zhou(周雨威)2, Meng Zhang(张濛)1, Xiaohua Ma(马晓华)1, and Yue Hao(郝跃)1
Zhihong Chen(陈治宏)1, Minhan Mi(宓珉瀚)1,3,†, Jielong Liu(刘捷龙)2, Pengfei Wang(王鹏飞)1, Yuwei Zhou(周雨威)2, Meng Zhang(张濛)1, Xiaohua Ma(马晓华)1, and Yue Hao(郝跃)1
摘要: We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors (HEMTs) with thin-barrier to minimize surface leakage current to enhance the breakdown voltage. The bilayer SiN with 20-nm Si-rich SiN and 100-nm Si$_{3}$N$_{4}$ was deposited by plasma-enhanced chemical vapor deposition (PECVD) after removing 20-nm SiO$_{2}$ pre-deposition layer. Compared to traditional Si$_{3}$N$_{4}$ passivation for thin-barrier AlGaN/GaN HEMTs, Si-rich SiN bilayer passivation can suppress the current collapse ratio from 18.54% to 8.40%. However, Si-rich bilayer passivation leads to a severer surface leakage current, so that it has a low breakdown voltage. The 20-nm SiO$_{2}$ pre-deposition layer can protect the surface of HEMTs in fabrication process and decrease Ga-O bonds, resulting in a lower surface leakage current. In contrast to passivating Si-rich SiN directly, devices with the novel Si-rich SiN bilayer passivation increase the breakdown voltage from 29 V to 85 V. Radio frequency (RF) small-signal characteristics show that HEMTs with the novel bilayer SiN passivation leads to $f_{\rm T}/f_{\rm max}$ of 68 GHz/102 GHz. At 30 GHz and $V_{\rm DS} = 20$ V, devices achieve a maximum $P_{\rm out}$ of 5.2 W/mm and a peak power-added efficiency (PAE) of 42.2%. These results indicate that HEMTs with the novel bilayer SiN passivation can have potential applications in the millimeter-wave range.
中图分类号: (III-V semiconductors)