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

作     者：杨凌 马晓华 冯倩 郝跃 

作者机构：Key Laboratory of Ministry of Education for Wide Band Gap Semiconductor Material and DeviceInstitute of MicroelectronicsXidian University 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2008年第17卷第7期

页      面：2696-2700页

核心收录：

学科分类：08[工学] 0803[工学-光学工程] 

基　　金：supported by the National High Technology Development Program of China (Grant No 2006AA03A108) 

主　　题：GaN based LED electrical stress pits annealing mechanism of degradation 

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.