GaN基LED电流分布的芯片结构优化设计  

Optimization Design of the Chip Structure for Current Distribution in the GaN-Based LED

作　　者：罗剑生 柴广跃[1] 刘文[1] 刘志慧[1] 

机构地区：[1]深圳大学光电工程学院,广东深圳518060

出　　处：《半导体技术》2016年第11期822-826,880,共6页Semiconductor Technology

基　　金：广东省产学研资助项目(2011B090400400);广东省前沿与关键技术创新专项资金资助项目(2014B010120004);深圳市重大产业攻关资助项目(JSGG20140519105124218)

摘　　要：GaN基LED的电流横向扩展导致电流分布不均匀的现象仍是目前亟待解决的难题,对于高压倒装LED更是如此。传统的LED工艺把负电极直接制作在n-GaN材料表面,而提出的优化结构是负电极内嵌于n-GaN材料。首先通过LED电流扩展的简单建模来探讨器件内部的电流分布情况,得出优化结构有利于改善芯片内部电流分布的理论推导。再进一步用SILVACO软件对优化结构和传统结构芯片内部电流分布进行了仿真对比,结果表明前者电流密度仅为后者的55%。最后制作了相关LED芯片样品进行热阻测试对比,实验表明优化结构芯片的结温和热阻较传统结构分别下降了13%和26%。可见芯片结构的优化设计方案是有效可行的。The non-uniformity of current distribution resulted from the current lateral spreading in GaN-based LEDs is still a difficult problem to be solved,especially for high-voltage flip chip LEDs. The cathode is located on the surface of n-GaN materials by traditional LED technology,while the proposed optimized structure is that the cathode is embedded in the n-GaN materials. Firstly,the current distribution inside the device was discussed by the simple modeling of LED current spreading,which showed that the optimized structure was favorable to improve the theoretical derivation of the current distribution inside the chip. Then the current distribution inside the chip of the optimized structure and traditional structure was simulated and compared with the software of SILVACO,which showed that the current density of the former was only 55% that of the latter. Finally,relevant samples of LED chips were fabricated to carry out the thermal resistance test comparison. The experimental results show that the junction temperature and thermal resistance of the optimized structure chip are dropped by 13% and 26% of the traditional structure chip,respectively. Therefore,the optimization design scheme of the chip structure is effective and feasible.

关 键 词：GAN基LED 电流扩展 结构优化 电流分布仿真 热阻测试 

分 类 号：TN364.2[电子电信—物理电子学] TN304.23