Effect of surface treatment of GaN based light emitting diode wafers on the leakage current of light emitting diode devices  

作　　者：王良吉 张书明 朱继红 朱建军 赵德刚 刘宗顺 江德生 王玉田 杨辉 

机构地区：[1]State Key Laboratory on Integrated Optoelectronics,Institute of Semiconductors,Chinese Academy of Sciences [2]Suzhou Institute of Nano-tech and Nano-bionics,Chinese Academy of Sciences

出　　处：《Chinese Physics B》2010年第1期501-504,共4页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos. 60776047, 60836003, 60476021 and 60576003)

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.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.

关 键 词：GAN light emitting diode surface treatment leakage current 

分 类 号：TN312.8[电子电信—物理电子学] TM862[电气工程—高电压与绝缘技术]