【作者】 熊传兵；

【导师】 张萌； 江风益；

【作者基本信息】 南昌大学 ， 材料物理与化学， 2008， 博士

【摘要】 InGaAlN MQW LED发光器件已在很多领域获得了广泛运用,与人们的生活生产息息相关。蓝宝石衬底和碳化硅衬底InGaAlN MQW发光器件于十几年前相继在日本和美国实现产业化并销往世界各地,它给人们的视觉增添了新的光彩。硅衬底InGaAlN MQW发光器件近年在中国率先实现产业化,它圆了全球GaN研究人员多年的美梦。无论是哪种衬底的InGaAlN QW发光器件,其性能的研究和提高都是永恒的课题。相比之下,硅衬底InGaAIN MQW LED发光器件其性能研究的深入程度由于开发时间较晚,还远不及其它两种衬底的发光器件的深入程度,因而深入研究硅衬底InGaAlN MQW LED发光器件的性能显得很有必要。本论文用压焊剥离和镀制剥离的方法获得了上下电极结构InGaAlN MQW LED发光器件并对其光电性能进行了一定研究,着重研究了垂直结构硅衬底InGaAlNMQW LED薄膜压焊转移引入的应力问题及其相关联的器件性能问题。本论文主要内容如下:1、第二章研究了垂直结构芯片在不同空间角度上的EL光谱,说明了硅衬底垂直结构的InGaAlN MQW LED的EL光谱中多个峰型来源于干涉现象,干涉峰随角度的变化情况可以反映P型层及P型欧姆接触层的状况。2、第三章研究了InGaAlN MQW LED薄膜处在外延片上、压焊到新衬底上、自由支撑薄膜的应力状态及光电性能的差别,研究结果表明LED薄膜在衬底剥离转移过程中缓冲层、N型层、P型层、阱层和垒层的应力状态均会发生一定程度的变化,从而与其相关联的光电性能也会发生变化。同时,根据硅衬底GaN外延片的特点,选择了一种物理沉积的方法在外延片上镀制金属基板,并通过控制镀制温度、基板层厚方向的组分分布及热膨胀系数分布等方法实现了LED薄膜应力状态的可控。3、第四章第一节用巨大正向电流对垂直结构InGaAlN芯片进行较长时间的剧烈老化,研究结果表明剧烈老化后的器件其阱层、垒层和耗尽层等均会发生一定程度的变化,从而与其相关的光电性能也会发生一定程度的变化。第二节通过对垂直结构InGaAlN MQW LED长时间加反向偏压,发现反向偏置后其光电性能均发生了明显的改变,器件性能的改变主要对应着内部载流子分布的改变。4、第五章第一节研究了室温(300K)和高温140℃(413K)的垂直结构的InGaAlNMQW LED的EL发光和正反向Ⅰ-Ⅴ特性。第二节研究了垂直结构InGaAlN芯片从10K至300K各环境温度下不同电流密度的EL光谱以及10K和300K环境温度下的正反向Ⅰ-Ⅴ特性。第三节将经过环氧树脂封装的垂直结构InGaAlN MQW LED表面沙毛,试图研究其低温下的发光及电学性能,测试了10K和300K两个环境温度下不同电流密度的EL光谱及Ⅰ-Ⅴ特性。第四节研究了30mA正向电流室温(300K)老化168小时、高温85℃(358K)老24小时,以及未老化的垂直结构的InGaAlN MQW LED的光电性能。研究结果表明压焊金属层会对LED薄膜的应力产生重要影响,在不同温度不同电流情况下EL发光来自于不同的阱层,同时温度对器件的晶体结构和载流子浓度的分布等均会产生一定程度的影响。更多还原

【Abstract】 The InGaAlN MQW LEDs play more and more important roles in our daily life, it has been applied in a lot of fields,such as back lightting,traffic signal lamp,and outdoor display,and so on.InGaAlN films grown on Al₂O₃ or SiC and its device, have been realized industrialization about a decade years ago,in America and Japan one after another.The industrialization of the growth of InGaAlN MQW LED films on Si substrate and the manufacture of the emission device has realized in china in the recent years,it is a very good news for the researchers all over the world. Wheather the InGaAlN MQW LED is grown on Al₂O₃ or SiC,research and improve its properties is a hard task forever.Compared with the tow others substrates,the study of the properties of the InGaAlN LEDs grown on Si has a long way need to go.So,it is very important to deeply study the properties of the LEDs grown on Si.In this thesies,we use the wafer-bonding or the sputtering technology combine with the lift-off technology,have successfully transfered the InGaAlN MQW LED film from the Si（111）substrate to another new submount,and have manufactured the vertical structure LED devices.At the same time,we have investigated the properties of the vertical structure devices deeply,especially we have studied the associated strain problem.The content of the study and the significant results are followed as:1、In the second chapter,the EL spectram of the vertical structure LEDs chip detected at various different spacial angle have been investigated.The multiple peak of the spectram of the vertical chip is derived from the interference,and the density of the interference peak could indicate the thickness uniformity of the P type layer,the intensity of the interference peak could indicate the reflectivity of the P type ohmic contact metal.2、In the third chapter,the different strain and associated properties between the LED film grown on Si（111）substrate,transferred to new submount and the freestanding film have been investigated.It indicate that when the film in different status it will appear different structural,optical and electrical properties.Sputtering a thick metal layer on the LED film wafer,and then chemical etching the Si substrate, the LED films were successfully transferred from Si（111）substrate to the metal submount,and has obtained the vertical structure LED on metal substrate.By control the thermal expansion efficiency and the sputtering temperature we have realized the control of the stress state in the LED film.3、In the fouth chapter,the changes of the properties before and after a long time reverse bias of the chip have been investigated,the changes of the properties before and after a long time reverse bias of the chip have been investigated too.The changes of the properties is derived from the variation of the distribution of the carrier and the space charge region.4、In the fifth chapter,the optical and electrical difference between the LED at 300K and at 413K,the optical and electrical difference between the LED chip’s at 10K and at 300K,the optical and electrical difference between the LED lamp after roughening the epoxy surface at 10K and at 300K,the optical and electrical difference between the aged LED at different condition and the LED without aging have been investigated.It indicate that the bonding metal will arose obvious change of the strain of the transferred LED film,and the space charge region,carrier distribution,emission well layer,and so on will appear a abvious change,while change the ambient temperature.更多还原