Han Zhanfei, Li Xiangdong, Wang Hongyue, Yuan Jiahui, Wang Junbo, Wang Meng, Yang Weitao, You Shuzhen, Chang Jingjing, Zhang Jincheng, Hao Yue
Guangzhou Wide Bandgap Semiconductor Innovation Center, Guangzhou Institute of Technology, Xidian University, Guangzhou 510555, China.
China Electronic Product Reliability and Environmental Testing Research Institute, Guangzhou 511370, China.
Micromachines (Basel). 2023 Apr 26;14(5):940. doi: 10.3390/mi14050940.
The channel temperature distribution and breakdown points are difficult to monitor for the traditional p-GaN gate HEMTs under high power stress, because the metal gate blocks the light. To solve this problem, we processed p-GaN gate HEMTs with transparent indium tin oxide (ITO) as the gate terminal and successfully captured the information mentioned above, utilizing ultraviolet reflectivity thermal imaging equipment. The fabricated ITO-gated HEMTs exhibited a saturation drain current of 276 mA/mm and an on-resistance of 16.6 Ω·mm. During the test, the heat was found to concentrate in the vicinity of the gate field in the access area, under the stress of V = 6 V and V = 10/20/30 V. After 691 s high power stress, the device failed, and a hot spot appeared on the p-GaN. After failure, luminescence was observed on the sidewall of the p-GaN while positively biasing the gate, revealing the side wall is the weakest spot under high power stress. The findings of this study provide a powerful tool for reliability analysis and also point to a way for improving the reliability of the p-GaN gate HEMTs in the future.
对于传统的p-GaN栅极高电子迁移率晶体管（HEMT），在高功率应力下，沟道温度分布和击穿点难以监测，因为金属栅极会阻挡光线。为了解决这个问题，我们采用透明氧化铟锡（ITO）作为栅极端对p-GaN栅极HEMT进行了处理，并利用紫外反射率热成像设备成功捕获了上述信息。所制备的ITO栅极HEMT表现出276 mA/mm的饱和漏极电流和16.6 Ω·mm的导通电阻。在测试过程中，发现在V = 6 V以及V = 10/20/30 V的应力下，热量集中在接入区域的栅极电场附近。在691 s的高功率应力之后，器件失效，并且在p-GaN上出现了一个热点。失效后，在对栅极进行正向偏置时，在p-GaN的侧壁上观察到发光现象，这表明侧壁是高功率应力下最薄弱的点。本研究的结果为可靠性分析提供了有力工具，也为未来提高p-GaN栅极HEMT的可靠性指明了方向。
