Mechanism of surface conduction in the vicinity of Schottky gates on AlGaN∕GaN heterostructures
Mechanism of surface conduction in the vicinity of Schottky gates on AlGaN∕GaN heterostructures
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DOI：
10.1063/1.2775834
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发表时间：
2007-08
影响因子：
4
通讯作者：
J. Kotani;M. Tajima;S. Kasai;T. Hashizume
中科院分区：
文献类型：
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作者：
J. Kotani;M. Tajima;S. Kasai;T. Hashizume
采用间隙距离（LGG）为200 nm-5μm的双平行栅结构，系统研究了AlGaN scinGaN异质结的侧面漏电流（Is）.表面电流随LGG的减小而增大。当LGG减小到小于1μm时，一个简单的电阻层传导应该表现出1 scinLGG依赖性，但却不能解释Is的急剧增加。然而，在肖特基界面中流动的垂直电流中没有看到对LGG的依赖性。Is显示出与exp（−T−1 scin 3）成比例的明显温度依赖性，表明AlGaN中通过高密度表面电子态的二维可变范围跳跃。在SiNx钝化的样品中观察到几乎四个数量级的表面电流的显着减少。
Lateral surface leakage current (Is) on an AlGaN∕GaN heterostructure was systematically investigated by using a two-parallel gate structure with a gap distance (LGG) of 200nm–5μm. The surface current Is systematically increased as LGG decreased. A simple resistive layer conduction that should show 1∕LGG dependence failed to account for the drastic increase in Is when LGG was reduced to less than 1μm. However, no dependence on LGG was seen in vertical current that flows in the Schottky interface. The Is showed a clear temperature dependence proportional to exp(−T−1∕3), indicating two-dimensional variable-range hopping through high-density surface electronic states in AlGaN. A pronounced reduction in surface current of almost four orders of magnitude was observed in a sample with SiNx passivation.