Impact of Intrinsic Stress in Diamond Capping Layers on the Electrical Behavior of AlGaN/GaN HEMTs
Impact of Intrinsic Stress in Diamond Capping Layers on the Electrical Behavior of AlGaN/GaN HEMTs
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DOI：
10.1109/ted.2013.2275031
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发表时间：
2013-10-01
影响因子：
3.1
通讯作者：
Kuball, Martin
中科院分区：
文献类型：
--
作者：
Wang, Ashu;Tadjer, Marko J.;Kuball, Martin
建立了AlGaN/GaN高电子迁移率晶体管的二维电子气（2-DEG）密度、压电极化电荷QP和由纳米金刚石覆盖层引起的本征应力的有限元模型。假设表面电势不受来自金刚石帽的附加应力的影响，则来自金刚石帽的张应力导致异质结构中的附加张应力，从而导致栅极下的2-DEG增加。结果，栅极边缘附近的附加压缩应力将发展并导致源极和漏极接触（SDC）之间的区域中的2-DEG减小。增加的饱和漏极电流将是由于SDC之间的总电阻减小。从SDC的2-DEG密度的整合揭示了与总片电荷浓度保持不变的片密度的重新分布。将模拟结果与拉曼光谱和I-V特性的实验数据进行了比较，得到了较好的一致性。
A finite-element model coupling 2-D electron gas (2-DEG) density, piezoelectric polarization charge QP, and intrinsic stress induced by a nanocrystalline diamond capping layer, was developed for AlGaN/GaN high electron mobility transistors. Assuming the surface potential is unchanged by an additional stress from diamond capping, tensile stress from the diamond cap leads to an additional tensile stress in the heterostructure and, thus an increase in the 2-DEG under the gate. As a result, additional compressive stress near the gate edges would develop and lead to decreased 2-DEG in the regions between the source and drain contacts (SDCs). Increased saturation drain current will be due to the reduced total resistance between SDC. Integration of the 2-DEG density from SDC revealed a redistribution of sheet density with total sheet charge concentration remaining unchanged. The modeling results were compared with the experimental data from Raman spectroscopy and I-V characterization, and good agreements were obtained.