中国物理B ›› 2010, Vol. 19 ›› Issue (1): 17307-017307.doi: 10.1088/1674-1056/19/1/017307
王良吉1, 张书明1, 朱继红1, 朱建军1, 赵德刚1, 刘宗顺1, 江德生1, 王玉田1, 杨辉2
Wang Liang-Ji(王良吉)a), Zhang Shu-Ming(张书明)a)†, Zhu Ji-Hong(朱继红)a), Zhu Jian-Jun(朱建军)a), Zhao De-Gang(赵德刚)a), Liu Zong-Shun(刘宗顺)a), Jiang De-Sheng(江德生)a), Wang Yu-Tian(王玉田) a) , and Yang Hui(杨辉)a)b)
摘要: 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.
中图分类号: (Light-emitting devices)