Methodology for the investigation of threading dislocations as a source of vertical leakage in AlGaN/GaN-HEMT heterostructures for power devices
Methodology for the investigation of threading dislocations as a source of vertical leakage in AlGaN/GaN-HEMT heterostructures for power devices
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DOI：
10.1063/1.5065442
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发表时间：
2019-03-07
影响因子：
3.2
通讯作者：
Erlbacher, T.
中科院分区：
文献类型：
--
作者：
Besendoerfer, S.;Meissner, E.;Erlbacher, T.
在这项工作中，AlGaN/GaN-HEMT异质结构是典型的研究，严格的地方到地方的相关性的方法，以帮助澄清一些开放的问题，在广泛的领域的可靠性主题。特别是，垂直漏电流，它的关系，位错一般，特别是特定类型的高度缺陷的材料进行了研究。借助原子力显微镜（AFM）的轻敲模式、阴极发光成像、缺陷选择性刻蚀和能量色散X射线，分析了与二维电子气相关的器件周围材料的缺陷含量。系统地直接研究了总位错密度以及螺位错、刃位错和混合型位错的密度。所得结果在统计学上比常规透射电子显微镜研究更显着，并且比摇摆曲线分析的间接方法获得的结果更精确。导电AFM的方法允许映射的变化，在垂直漏电流，这可能与势垒泄漏或栅极泄漏的变化。可以观察到局部高漏电流的点，并直接分配到位错与螺钉组件，但即使在同一组的位错类型的显着差异。位错的电活动一般进行了讨论，并提出了一个潜在的位错驱动的垂直泄漏的基本模型。(C)2019年作者。
In this work, an AlGaN/GaN-HEMT heterostructure is exemplarily studied by a strict place-to-place correlational approach in order to help clarify some open questions in the wide field of reliability topics. Especially, vertical leakage current, its relation to dislocations in general, and specific types in particular are investigated on a highly defective material. With the aid of atomic force microscopy (AFM) in tapping mode, cathodoluminescence imaging, defect selective etching, and energy dispersive X-ray, the material's defect content around the device relevant two dimensional electron gas is analyzed. The total dislocation density, as well as the density of threading screw, edge, and mixed type dislocations, is systematically investigated directly. The obtained result is statistically much more significant than is possible by conventional transmission electron microscopy studies and more precise than the results obtained by the indirect method of rocking curve analysis. The method of conductive AFM allowed mapping of variations in the vertical leakage current, which could be correlated with variations in barrier leakage or gate leakage. Spots of locally high leakage current could be observed and directly assigned to dislocations with a screw component, but with significant differences even within the same group of dislocation types. The electrical activity of dislocations is discussed in general, and a fundamental model for a potential dislocation driven vertical leakage is proposed. (C) 2019 Author(s).