The effects of an LPCVD SiN x stack on the threshold voltage and its stability in AlGaN/GaN MIS-HEMTs
The effects of an LPCVD SiN x stack on the threshold voltage and its stability in AlGaN/GaN MIS-HEMTs
复制标题
DOI：
10.1088/1361-6641/ac5e00
复制
发表时间：
2022-03
影响因子：
1.9
通讯作者：
Xuemei Yin;Chengguo Li;Q. Zeng;Xiaowan Ge;Zhi-Tao Chen
中科院分区：
文献类型：
--
作者：
Xuemei Yin;Chengguo Li;Q. Zeng;Xiaowan Ge;Zhi-Tao Chen
在本工作中，我们系统地研究了低压化学气相沉积SiNx双层膜的化学计量比和厚度对AlGaN/GaN异质结金属-绝缘体-半导体高电子迁移率晶体管电学性质的影响。富硅的SiNx单层降低了栅应力下的阈值电压漂移和磁滞，但导致了较高的栅漏。接近化学计量比的SiNx单层抑制了栅漏，但导致了较差的栅稳定性。具有优化厚度比的双层SiNx堆栈在保持低电流泄漏的同时改善了栅极稳定性和导通电阻。由5 nm富硅SiNx界面层和15 nm SiNx覆盖层组成的双层SiNx堆栈具有最低的方阻和最高的栅极稳定性。这种增强的栅稳定性是由于陷阱态密度低、富硅SiNx/GaN界面的电场减弱以及双层界面上额外的正电荷所致。
In this work, we systematically studied the stoichiometry and thickness effects of low-pressure chemical vapor deposited SiN x bilayer stacks on the electrical properties of AlGaN/GaN heterojunction-based metal–insulator-semiconductor high electron mobility transistors. A Si-rich SiN x single layer reduces threshold voltage shift and hysteresis under gate stress but gives rise to high gate leakage. A near-stoichiometric SiN x single layer suppresses gate leakage but causes poor gate stability. A bilayer SiN x stack with an optimized thickness ratio improves both the gate stability and on-resistance while maintaining a low current leakage. The bilayer SiN x stack consisting of a 5 nm Si-rich SiN x interfacial layer and a 15 nm SiN x capping layer resulted in the lowest sheet resistance and the highest gate stability. Such enhanced gate stability is explained by the low density of trap states and the weakened electric field at the Si-rich SiN x /GaN interface and an extra positive charge at the bilayer interface.