Vertical leakage mechanism in GaN on Si high electron mobility transistor buffer layers
Vertical leakage mechanism in GaN on Si high electron mobility transistor buffer layers
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DOI：
10.1063/1.5027680
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发表时间：
2018-08-07
影响因子：
3.2
通讯作者：
Wallis, D. J.
中科院分区：
文献类型：
--
作者：
Choi, F. S.;Griffiths, J. T.;Wallis, D. J.
Si衬底上GaN基晶体管缓冲层中漏电流的控制对于高性能器件的演示至关重要。在这里，我们表明，在金属有机化学气相沉积生长的梯度AlGaN应变消除层（SRL）的生长条件可以显着影响的垂直泄漏。使用扫描电容显微镜，二次离子质谱，和透射电子显微镜，我们调查的泄漏路径的起源，并表明，它们导致从优先纳入的氧杂质的侧壁面上的倒六角锥形坑，可以发生在生长过程中的渐变AlGaN SRL。我们还表明，当二维生长的AlGaN SRL保持击穿电压的显着增加，可以实现即使在更薄的缓冲层结构。这些结果证明了控制高电子迁移率晶体管缓冲层的形态的重要性，因为即使在非常低的密度下，所识别的泄漏路径也会在大面积器件中提供泄漏路径。(C)2018年作者。
Control of leakage currents in the buffer layers of GaN based transistors on Si substrates is vital for the demonstration of high performance devices. Here, we show that the growth conditions during the metal organic chemical vapour deposition growth of the graded AlGaN strain relief layers (SRLs) can significantly influence the vertical leakage. Using scanning capacitance microscopy, secondary ion mass spectrometry, and transmission electron microscopy, we investigate the origins of leakage paths and show that they result from the preferential incorporation of oxygen impurities on the side wall facets of the inverted hexagonal pyramidal pits which can occur during the growth of the graded AlGaN SRL. We also show that when 2D growth of the AlGaN SRL is maintained a significant increase in the breakdown voltage can be achieved even in much thinner buffer layer structures. These results demonstrate the importance of controlling the morphology of the high electron mobility transistor buffer layer as even at a very low density the leakage paths identified would provide leakage paths in large area devices. (C) 2018 Author(s).