中国物理B ›› 2008, Vol. 17 ›› Issue (7): 2696-2700.doi: 10.1088/1674-1056/17/7/056

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Reliability analysis of GaN-based light emitting diodes for solid state illumination

杨凌, 马晓华, 冯倩, 郝跃   

  1. Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Microelectronics Institute, Xidian University, Xi'an 710071, China
  • 收稿日期:2007-11-14 修回日期:2008-01-25 出版日期:2008-07-09 发布日期:2008-07-09
  • 基金资助:
    Project supported by the National High Technology Development Program of China (Grant No 2006AA03A108).

Reliability analysis of GaN-based light emitting diodes for solid state illumination

Yang Ling(杨凌)†, Ma Xiao-Hua(马晓华), Feng Qian(冯倩), and Hao Yue(郝跃)   

  1. Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Microelectronics Institute, Xidian University, Xi'an 710071, China
  • Received:2007-11-14 Revised:2008-01-25 Online:2008-07-09 Published:2008-07-09
  • Supported by:
    Project supported by the National High Technology Development Program of China (Grant No 2006AA03A108).

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摘要： In this paper, we have discussed the effect of electrical stress on GaN light emitting diode (LED). With the lapse of time, the LED with an applied large current stress can reduce its current more than without such a stress under a large forward-voltage drop. Its scanning electron microscopy (SEM) image shows that there exist several pits on the surface of the p-metal. With an electrical stress applied, the number of pits greatly increases. We also find that the degradation of GaN LED is related to the oxidized Ni/Au ohmic contact to p-GaN. The electrical activation of H-passivated Mg acceptors is described in detail. Annealing is performed in ambient air for 10 min and the differential resistances at a forward-voltage drop of 5\,V are taken to evaluate the activation of the Mg acceptors. These results suggest some mechanisms of degradation responsible for these phenomena, which are described in the paper.

关键词: GaN based LED, electrical stress, pits, annealing, mechanism of degradation

Abstract: In this paper, we have discussed the effect of electrical stress on GaN light emitting diode (LED). With the lapse of time, the LED with an applied large current stress can reduce its current more than without such a stress under a large forward-voltage drop. Its scanning electron microscopy (SEM) image shows that there exist several pits on the surface of the p-metal. With an electrical stress applied, the number of pits greatly increases. We also find that the degradation of GaN LED is related to the oxidized Ni/Au ohmic contact to p-GaN. The electrical activation of H-passivated Mg acceptors is described in detail. Annealing is performed in ambient air for 10 min and the differential resistances at a forward-voltage drop of 5 V are taken to evaluate the activation of the Mg acceptors. These results suggest some mechanisms of degradation responsible for these phenomena, which are described in the paper.

Key words: GaN based LED, electrical stress, pits, annealing, mechanism of degradation

中图分类号:  (Light-emitting devices)

  • 85.60.Jb
68.37.Hk (Scanning electron microscopy (SEM) (including EBIC)) 73.40.Ns (Metal-nonmetal contacts) 81.40.Ef (Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization)