硅衬底GaN基LED光电性能及可靠性研究

发布时间：2018-05-25 06:57

本文选题：电子阻挡层 + 光功率　；参考：《南昌大学》2015年硕士论文

【摘要】：GaN基LED凭借其可控的全色光谱能隙以及优良的物理化学性能,已逐步成为新一代绿色照明光源。为了获得真正意义上的高品质白光LED照明光源,需要采用全LED混光来实现,需要采用红、绿、蓝三基色(RGB)的全LED混光来实现,但是目前绿光的发光效率远远落后于蓝光和红光LED,学术界称之为“Green gap”,这也成为实现RGB白光光源的主要技术瓶颈。因此,进一步提升绿光LED的光功率成为近几年LED领域的研究热点。基于硅衬底LED技术平台,本文在保持p-GaN总体厚度不变的情况下通过改变靠近最后一个量子阱的电子阻挡层(EBL)AlGaN的厚度,较为系统地研究了电子阻挡层对硅衬底绿光LED的光功率(LOP)和工作电压(VF2)的影响,另外经过长时间对p-GaN中Mg掺杂浓度的跟踪和外延薄膜表面形貌的观察以及大量LED在老化过程中IR变化实验进行了总结。主要获得了以下研究成果:1、硅衬底GaN基绿光LED外延片薄膜在保持p层总体厚度不变的情况下对靠近最后一个量子阱的电子阻挡层(EBL)AlGaN厚度的进行了优化及可靠性实验,结果表明,p-AlGaN厚度为200?及P-InGaN厚度为400?的样品D具有更高的光功率(LOP),且光电性能稳定。并对其在大电流时光功率提高进行了解释:大电流密度下随着p-AlGaN的减薄使得该区域的电场增强,导致电子的有效势垒高度增加和空穴有效势垒高度减小。2、Mg掺杂浓度偏多会使芯片电压偏高,因此需对P-GaN的掺Mg进行简便有效地监控。经过长期测试发现,p-GaN中Mg掺杂浓度偏高时在10μm*10μm的原子力显微镜(AFM)扫描范围内台阶流不明显,而且会出现一些像小山丘一样的凸起。并用二次离子质谱仪(SIMS)对Mg元素进行了深度剖析,结果显示有凸起出现的样品中Mg的掺杂浓度确实偏高。因此提出用AFM方法快捷方便地监控Mg的掺杂量。3、通过光电参数控制严格筛选出IR有差别的芯片,在大量老化实验中发现IR小于0.05μA时筛选的芯片老化过程中相对稳定,通过加载300V的静电后可以筛选出高质量的芯片,IR在0.05μA至0.1μA范围内的芯片老化过程中IR的稳定性没有前者高,而且只有加载1000V及以上的静电后才能筛选出相对较好的芯片,IR在0.1μA至1μA内的芯片老化效果较差,并且很难选出好的芯片。为筛选出的稳定性好的芯片,建议点测时加相对小的静电和分选时控制IR在较小的的范围内相结合的方法进行筛选。
[Abstract]:GaN based LED has gradually become a new generation of green light source with its controllable panchromatic spectral energy gap and excellent physical and chemical properties. In order to obtain the real high quality white light LED lighting source, all LED mixed light needs to be realized. The full LED mixed light of red, green and blue three basic colors (RGB) needs to be realized, but the green light is present at present. The luminescence efficiency is far behind the blue and red LED, which academic circles call "Green gap", which is also the main technical bottleneck for the realization of the RGB white light source. Therefore, to further improve the light power of the green light LED has become the research hotspot in the field of LED in recent years. Based on the flat platform of LED technology on the silicon substrate, this paper keeps the overall thickness of p-GaN unchanged. By changing the thickness of the electronic barrier layer (EBL) AlGaN near the last quantum well, the effects of the electronic barrier layer on the optical power (LOP) and the working voltage (VF2) of the green LED on silicon substrate are systematically investigated. In addition, the observation of the trace of the Mg doping concentration in p-GaN and the surface morphology of the epitaxial film in the p-GaN and a large number of LED in the old are also studied. The IR change experiments in the process are summarized. The main results are as follows: 1, the thickness of the electronic barrier layer (EBL) AlGaN near the last quantum well is optimized and dependable under the condition of keeping the overall thickness of the p layer unchanged. The results show that the thickness of the p-AlGaN is 200? And P-. The results show that the thickness of the p-AlGaN is 200? And P-. The sample D with a thickness of 400? With a thickness of 400? Has a higher optical power (LOP) and a stable optoelectronic performance. An explanation is made of the increase in the time power of the high current. With the decrease of the current density, the electric field of the region increases with the decrease of the p-AlGaN, resulting in the effective barrier height of the electrons and the decrease of the effective barrier height of the hole.2 and the Mg doping concentration. The voltage of the chip is much higher, so it is necessary to monitor and control the P-GaN doped Mg easily and effectively. After a long test, it is found that the Mg doping concentration in the p-GaN is not obvious in the 10 mu m*10 m atomic force microscope (AFM) scanning range, and there will be some bulges like the hills. And the two ion mass spectrometer (SIMS) is used for Mg. The depth analysis of the elements shows that the doping concentration of Mg in the samples with protruding is really high. Therefore, it is proposed that the doping amount of Mg can be monitored quickly and conveniently by AFM method, and the differential chip of IR is screened out strictly through the photoelectric parameter control. In a large number of aging experiments, the selected chip aging process is found when IR is less than 0.05 u A. Relatively stable, high quality chips can be screened by loading 300V static electricity. The stability of IR in the process of IR in the range of 0.05 to 0.1 A is not high, and only after loading 1000V and above, the relatively better chip can be screened. The aging effect of IR from 0.1 to 1 u A is poor, and it is very bad. It is difficult to select a good chip. In order to screen out the stable chip, it is suggested that the method of combination of relatively small static electricity and separation to control the combination of IR in a smaller range is proposed.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ133.51;TN312.8

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