Choi Jun-Hyeok, Kang Woo-Seok, Kim Dohyung, Kim Ji-Hun, Lee Jun-Ho, Kim Kyeong-Yong, Min Byoung-Gue, Kang Dong Min, Kim Hyun-Seok
Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
Electronics and Telecommunications Research Institute, Daejeon 34129, Republic of Korea.
Micromachines (Basel). 2023 May 23;14(6):1101. doi: 10.3390/mi14061101.
This study investigates the operating characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) by applying HfO as the passivation layer. Before analyzing HEMTs with various passivation structures, modeling parameters were derived from the measured data of fabricated HEMT with SiN passivation to ensure the reliability of the simulation. Subsequently, we proposed new structures by dividing the single SiN passivation into a bilayer (first and second) and applying HfO to the bilayer and first passivation layer only. Ultimately, we analyzed and compared the operational characteristics of the HEMTs considering the basic SiN, only HfO, and HfO/SiN (hybrid) as passivation layers. The breakdown voltage of the AlGaN/GaN HEMT having only HfO passivation was improved by up to 19%, compared to the basic SiN passivation structure, but the frequency characteristics deteriorated. In order to compensate for the degraded RF characteristics, we modified the second SiN passivation thickness of the hybrid passivation structure from 150 nm to 450 nm. We confirmed that the hybrid passivation structure with 350-nm-thick second SiN passivation not only improves the breakdown voltage by 15% but also secures RF performance. Consequently, Johnson's figure-of-merit, which is commonly used to judge RF performance, was improved by up to 5% compared to the basic SiN passivation structure.
本研究通过应用HfO作为钝化层来研究AlGaN/GaN高电子迁移率晶体管（HEMT）的工作特性。在分析具有各种钝化结构的HEMT之前，从具有SiN钝化的制造HEMT的测量数据中得出建模参数，以确保模拟的可靠性。随后，我们提出了新的结构，将单一的SiN钝化分为双层（第一和第二层），并仅将HfO应用于双层和第一层钝化层。最终，我们分析并比较了以基本SiN、仅HfO和HfO/SiN（混合）作为钝化层的HEMT的工作特性。与基本SiN钝化结构相比，仅具有HfO钝化的AlGaN/GaN HEMT的击穿电压提高了高达19%，但频率特性恶化。为了补偿退化的射频特性，我们将混合钝化结构的第二层SiN钝化厚度从150 nm修改为450 nm。我们证实，具有350 nm厚第二层SiN钝化的混合钝化结构不仅将击穿电压提高了15%，而且确保了射频性能。因此，与基本SiN钝化结构相比，常用于判断射频性能的约翰逊优值提高了高达5%。
