Effect of surface treatment of GaN based light emitting diode wafers on the leakage current of light emitting diode devices
Effect of surface treatment of GaN based light emitting diode wafers on the leakage current of light emitting diode devices
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DOI：
10.1088/1674-1056/19/1/017307
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发表时间：
2010-01
影响因子：
1.7
通讯作者：
Liangliang Wang;Shuming Zhang;Jihong Zhu;Jian-jun Zhu;Degang Zhao;Zongshun Liu;D. Jiang;Yu-Tian Wang;Yang Hui
中科院分区：
文献类型：
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作者：
Liangliang Wang;Shuming Zhang;Jihong Zhu;Jian-jun Zhu;Degang Zhao;Zongshun Liu;D. Jiang;Yu-Tian Wang;Yang Hui
为了形成与p型GaN的低电阻欧姆接触，在Ni/Au（5 nm/5 nm）膜沉积之前用煮沸的王水处理InGaN/GaN多量子阱发光二极管晶片。研究了硅片的表面形貌和制作的发光二极管器件的电流-电压特性。结果表明，采用煮沸的王水处理可以有效地去除p-GaN层表面的氧化物，并显示出与x射线摇摆曲线测量的螺位错密度几乎相同的缺陷坑。这表明发光二极管器件的Ni/Au透明电极的金属原子可能沿着穿透位错线扩散到p-GaN层中并形成额外的漏电流通道。因此，用煮沸的王水进行表面处理的时间不宜过长，以免增加穿线位错引起的漏电流，降低发光二极管的电性能。
To form low-resistance Ohmic contact to p-type GaN, InGaN/GaN multiple quantum well light emitting diode wafers are treated with boiled aqua regia prior to Ni/Au (5 nm/5 nm) film deposition. The surface morphology of wafers and the current–voltage characteristics of fabricated light emitting diode devices are investigated. It is shown that surface treatment with boiled aqua regia could effectively remove oxide from the surface of the p-GaN layer, and reveal defect-pits whose density is almost the same as the screw dislocation density estimated by x-ray rocking curve measurement. It suggests that the metal atoms of the Ni/Au transparent electrode of light emitting diode devices may diffuse into the p-GaN layer along threading dislocation lines and form additional leakage current channels. Therefore, the surface treatment time with boiled aqua regia should not be too long so as to avoid the increase of threading dislocation-induced leakage current and the degradation of electrical properties of light emitting diodes.