Initial leakage current paths in the vertical-type GaN-on-GaN Schottky barrier diodes
Initial leakage current paths in the vertical-type GaN-on-GaN Schottky barrier diodes
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DOI：
10.1063/1.4994627
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发表时间：
2017-09
影响因子：
4
通讯作者：
L. Sang;B. Ren;M. Sumiya;M. Liao;Y. Koide;A. Tanaka;Yujin Cho;Y. Harada;T. Nabatame;T. Sekiguchi;S. Usami;Y. Honda;H. Amano
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文献类型：
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作者：
L. Sang;B. Ren;M. Sumiya;M. Liao;Y. Koide;A. Tanaka;Yujin Cho;Y. Harada;T. Nabatame;T. Sekiguchi;S. Usami;Y. Honda;H. Amano
利用光子发射显微镜（PEM）研究了独立GaN衬底上竖直型n-GaN肖特基势垒二极管（sdd）泄漏电流通路的电特性。PEM映射表明，SBD器件在低电压下的初始失效是由于GaN涂层中多边形凹坑的泄漏电流路径。显微组织分析表明，这些多角形凹坑是由碳杂质堆积和螺杆型位错引起的。对于没有多边形凹坑的SBD，没有观察到初始失效，由于电场浓度的作用，第一次泄漏发生在电极边缘。通过拟合电流-电压特性，从陷阱辅助隧穿的角度解释了坑漏的机理。
Electrical characteristics of leakage current paths in vertical-type n-GaN Schottky barrier diodes (SBDs) on free-standing GaN substrates are investigated by using photon emission microscopy (PEM). The PEM mapping shows that the initial failure of the SBD devices at low voltages is due to the leakage current paths from polygonal pits in the GaN epilayers. It is observed that these polygonal pits originate from carbon impurity accumulation to the dislocations with a screw-type component by microstructure analysis. For the SBD without polygonal pits, no initial failure is observed and the first leakage appeals at the edge of electrodes as a result of electric field concentration. The mechanism of leakage at pits is explained in terms of trap assisted tunneling through fitting current-voltage characteristics.