高光效GaN基高压LED器件制备

发布时间：2018-03-21 04:08

  本文选题：高压LED　切入点：芯片制备　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：高压发光二极管(HV-LED)具有工作电压高、驱动电流小等特点,可以解决多晶封装过程中存在的可靠性问题,并减少电压转换过程中的能源损失,因此成为了国内外的研究热点。本文针对正装结构Ga N高压LED芯片制备及光电性能进行研究,主要工作如下:为提升Ga N基高压LED芯片的出光效率,在蓝宝石背面设计制备了4对Ti3O5/Si O2(100nm/40nm)的分布布拉格反射层(4-MDBR)和包括4-MDBR以及金属铝层(60nm)结构的复合反射镜(4-MDBR-Al)。在20m A的注入电流下,4-MDBR-Al结构的高压LED芯片的出射光功率为294.4m W,相对于只有4层DBR结构(4-MDBR)的出射光功率提升了4.6%。针对如何提高侧面出射光功率从而提升其光效进行了光学仿真计算,结果表明芯片形状为正方形或长方形时,有效出光效率最高;侧面微结构形状为圆形凹凸相间排列的复合结构时,有效出光效率最高;进一步分析隔离沟槽间距对出光效率的影响,结果表明在无侧面微结构的情况下,有效光效极大值点在30μm处,而在有侧面微结构的情况下,有效光效极大值点在50μm处。为提升Ga N基高压LED芯片的出光性能,优化芯片发光单元之间隔离沟槽的宽度。本文在制备侧面微结构的基础上设计了4种不同隔离沟槽宽度(10μm、20μm、30μm以及40μm)的Ga N基高压LED芯片,并采用正装工艺进行制备,对其进行光电测试,实验结果表明隔离沟槽宽度为20μm的高压芯片的光电性能最佳。注入电流为20 m A时,正向电压50.72 V,输出光功率373.64 m W,电光转换效率36.83%。采用镜面铝基板和陶瓷基板进行四颗芯片串联形式的COB封装对比测试,结果表明基于镜面铝基板封装的正向电压、输出光功率、饱和光功率、饱和电流、光输出效率、光衰及温度造成的蓝光峰值波长红移都优于陶瓷基板,当注入电流为20m A且基板温度为20℃时,镜面铝基板封装的HV-LED器件的正向电压是198.9 V,光输出效率达122.2 lm/W。
[Abstract]:High voltage light-emitting diode (HV-LED) has the advantages of high working voltage and low driving current, which can solve the reliability problem in the process of polycrystalline packaging and reduce the energy loss in the process of voltage conversion. Therefore, it has become a research hotspot at home and abroad. In this paper, the fabrication and optoelectronic properties of Ga N high voltage LED chip are studied. The main work is as follows: in order to improve the light efficiency of gan high voltage LED chip, On the back of sapphire, four pairs of Ti3O5/Si O _ 2 O _ 2N _ (100 nm / / 40 nm) distributed Bragg reflectance layer (4-MDBR) and a composite mirror (including 4-MDBR and aluminum layer / 60nm) structure were designed and fabricated. The output power of the high-voltage LED chip with 4-MDBR-Al structure at 20mA injection current is as high as 4-MDBR-Al. 294.4mW, compared with only 4-layer DBR structure 4-MDBR, the output power is increased by 4.6m. the optical simulation calculation is carried out on how to increase the side light output power and improve its light efficiency. The results show that the efficient light output efficiency is the highest when the chip shape is square or rectangular, and the maximum effective light output efficiency is when the shape of the microstructure is a composite structure with circular concave and convex phase arrangement. The effect of the spacing of isolated grooves on the light efficiency is further analyzed. The results show that the maximum of effective light efficiency is at 30 渭 m in the absence of side microstructures, while in the case of side microstructures, the maximum of effective light efficiency is at 30 渭 m. The maximum of effective light efficiency is at 50 渭 m. In order to improve the output performance of gan based high voltage LED chip, On the basis of fabricating side microstructures, four kinds of gan based high voltage LED chips with different isolation groove widths (10 渭 m, 20 渭 m, 30 渭 m and 40 渭 m) were designed and fabricated. The experimental results show that the high voltage chip with isolation groove width of 20 渭 m has the best optoelectronic performance, and when the injection current is 20 Ma, The forward voltage is 50.72 V, the output optical power is 373.64 MW, and the electro-optic conversion efficiency is 36.83.The COB package of four chips in series is tested by using the mirror aluminum substrate and the ceramic substrate. The results show that the output optical power is based on the forward voltage of the mirror aluminum substrate package. The peak wavelength red shift of blue light caused by saturation optical power, saturated current, optical output efficiency, light decay and temperature is superior to that of ceramic substrate. When the injection current is 20 Ma and the substrate temperature is 20 鈩，

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