Physical insight of thin AlGaN back barrier for millimeter-wave high voltage AlN/GaN on SiC HEMTs

APPLIED PHYSICS LETTERS(2023)

引用 0|浏览7
暂无评分
摘要
In this work, physical mechanisms underlying carbon-doped buffer combined with an AlGaN back-barrier layer are investigated in state-of-the-art millimeter-wave AlN/GaN transistors. We have fabricated devices with and without the insertion of a thin AlGaN back-barrier layer with reduced carbon concentration to analyze the improvement resulting from this buffer architecture. More specifically, the impact of the Al mole fraction into the back-barrier, carbon doping in the buffer, and channel thickness on 100 nm gate length device performance has been studied. It appears that a 150 nm undoped GaN channel followed by a highly carbon-doped GaN buffer results in good electron confinement at the expense of a high current collapse. On the other hand, an Al mole fraction of 25% in the AlGaN back barrier layer coupled with a 150 nm undoped GaN channel provides excellent electron confinement, resulting not only in a low DIBL under high electric field but also low current collapse. Calibrated on experimental devices, TCAD simulations reveal that the electric field penetration inside the GaN buffer is prevented owing to a strong polarization from the back barrier when the Al-content is high enough. That is why, the electron confinement is superior for the 25% Al mole fraction in the back barrier along with reduced current collapse. As a result, careful engineering of the carbon concentration together with the undoped GaN channel thickness is crucial to achieve robust devices, which can, thus, deliver high device performance with superior voltage operation while using short gate lengths.
更多
查看译文
关键词
physical hemts,high voltage aln/gan,thin algan,millimeter-wave
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要