Poststress dc characteristics of AlGaN/GaN HEMTs can be used to study the effect of high-power stress on the noise figure (NF) and gain of low-noise amplifiers (LNAs) subjected to large input overdrives. This enables a shift from circuit- to transistor-level measurements to investigate the impact of variations in HEMT design parameters on the robustness (including both recovery time and survivability) by mimicking LNA operation. Using this method, a tradeoff between survivability and recovery time is demonstrated for different AlGaN/GaN interface profiles (sharp interface, standard interface, and AlN interlayer). Furthermore, the impact of different surface passivation schemes (Si-rich, Si-poor, and bilayer SiNx) on robustness is investigated. The bilayer passivation, which features low leakage current and small gain compression under overdrive stress, exhibits relatively weak survivability. The mechanisms influencing the robustness are analyzed based on transistor physics. The short recovery time is mainly due to impeding the injection of hot electrons into surface traps and high reverse current, whereas the survivability is dependent on the local or global peak electrical fields around the gate under high power stress.

中文翻译：

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AlGaN/GaN 界面和钝化对低噪声放大器稳健性的影响

AlGaN/GaN HEMT 的后应力直流特性可用于研究高功率应力对承受大输入过驱动的低噪声放大器 (LNA) 的噪声系数 (NF) 和增益的影响。这使得能够从电路级测量转向晶体管级测量，通过模拟 LNA 操作来研究 HEMT 设计参数变化对稳健性（包括恢复时间和生存能力）的影响。使用这种方法，可以针对不同的 AlGaN/GaN 界面轮廓（锐界面、标准界面和 AlN 夹层）证明生存能力和恢复时间之间的权衡。此外，还研究了不同表面钝化方案（富硅、贫硅和双层 SiNx）对稳健性的影响。双层钝化，具有低漏电流和过驱动应力下小增益压缩的特点，表现出相对较弱的生存能力。基于晶体管物理分析影响鲁棒性的机制。恢复时间短主要是由于阻止热电子注入表面陷阱和高反向电流，而生存能力取决于在高功率应力下栅极周围的局部或全局峰值电场。