中国物理B ›› 2010, Vol. 19 ›› Issue (1): 17307-017307.doi: 10.1088/1674-1056/19/1/017307

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

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   

  1. (1)State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (2)State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215125, China
  • 收稿日期:2009-04-30 修回日期:2009-05-25 出版日期:2010-01-15 发布日期:2010-01-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60776047, 60836003, 60476021 and 60576003).

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

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)   

  1. a State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; b Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215125, China
  • Received:2009-04-30 Revised:2009-05-25 Online:2010-01-15 Published:2010-01-15
  • Supported by:
    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.

Abstract: 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.

Key words: GaN, light emitting diode, surface treatment, leakage current

中图分类号:  (Light-emitting devices)

  • 85.60.Jb
61.72.Ff (Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)) 68.35.B- (Structure of clean surfaces (and surface reconstruction)) 73.40.Ns (Metal-nonmetal contacts) 81.65.-b (Surface treatments) 85.35.Be (Quantum well devices (quantum dots, quantum wires, etc.))