Evolution of structural defects associated with electrical degradation in AlGaN/GaN high electron mobility transistors
Evolution of structural defects associated with electrical degradation in AlGaN/GaN high electron mobility transistors
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DOI：
10.1063/1.3446869
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发表时间：
2010-06-07
影响因子：
4
通讯作者：
Thompson, Carl V.
中科院分区：
文献类型：
--
作者：
Makaram, Prashanth;Joh, Jungwoo;Thompson, Carl V.
我们通过化学蚀刻去除栅极金属化层后，使用原子力显微镜和扫描电子显微镜研究了电应力 AlGaN/GaN 高电子迁移率晶体管的表面形貌。表面形态的变化与电特性的退化相关。对于所有电应力器件，在 GaN 盖层中沿着栅极边缘形成线性凹槽。超过对应于栅极漏电流急剧增加的临界电压时，栅极边缘的表面上会形成凹坑。凹坑的密度和尺寸随着应力电压和时间的增加而增加，并与漏极电流和电流崩溃的退化相关。我们认为，AlGaN 层中由于高压应力而产生的高机械应力可以通过这些缺陷的形成来缓解，这些缺陷充当栅极漏电流的路径，并导致电子捕获和下方沟道传输性能的退化。 (C) 2010 年美国物理研究所。 [doi:10.1063/1.3446869]
We have investigated the surface morphology of electrically stressed AlGaN/GaN high electron mobility transistors using atomic force microscopy and scanning electron microscopy after removing the gate metallization by chemical etching. Changes in surface morphology were correlated with degradation in electrical characteristics. Linear grooves formed along the gate edges in the GaN cap layer for all electrically stressed devices. Beyond a critical voltage that corresponds to a sharp increase in the gate leakage current, pits formed on the surface at the gate edges. The density and size of the pits increase with stress voltage and time and correlate with degradation in the drain current and current collapse. We believe that high mechanical stress in the AlGaN layer due to high-voltage stressing is relieved by the formation of these defects which act as paths for gate leakage current and result in electron trapping and degradation in the transport properties of the channel underneath. (C) 2010 American Institute of Physics. [doi:10.1063/1.3446869]