High conductive gate leakage current channels induced by In segregation around screw- and mixed-type threading dislocations in lattice-matched InxAl1−xN/GaN heterostructures

作者：Jie Song, Fujun Xu, Xiaodong Yan, Fang Lin, Chung‐Che Huang, Long You, Tongjun Yu, Xinqiang Wang, Bo Shen, Wei Ke, X. Y. Liu · 发表于：Applied Physics Letters · 年份：2010 · DOI：10.1063/1.3525713 · 被引用次数：54 · 研究领域：GaN-based semiconductor devices and materials、Semiconductor materials and devices、Metal and Thin Film Mechanics

A correlation between microstructures and high gate leakage current density of Schottky contacts on lattice-matched InxAl1−xN/GaN heterostructures has been investigated by means of current-voltage measurements, conductive atom force microscopy (C-AFM), and transmission electron microscopy (TEM) investigations. It is shown that the reverse-bias gate leakage current density of Ni/Au Schottky contacts on InxAl1−xN/GaN heterostructures is more than two orders of magnitude larger than that on AlxGa1−xN/GaN ones. C-AFM and TEM observations indicate that screw- and mixed-type threading dislocations (S/M-TDs) are efficient leakage current channels in InxAl1−xN barrier and In segregation is formed around S/M-TDs. It is believed that In segregation around S/M-TDs reduces local Schottky barrier height to form conductive channels and leads to high leakage current density of Schottky contacts on InxAl1−xN/GaN heterostructures.