基于外延剥离技术的薄膜LEDs的电流扩展和热效应研究  

Current spreading and thermal effect in thin-film Light-Emitting Diodes for epitaxial lift-off technology

作　　者：李晓敏[1] 宗约瀚 江宇[1] 白霖[1] 宋国峰[1] 徐云[1] 

机构地区：[1]中国科学院半导体研究所,纳米光电子实验室,北京100083 [2]四川大学电气信息学院自动化系,成都610200

出　　处：《中国科学：物理学、力学、天文学》2016年第4期124-129,共6页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家重点基础研究发展计划(编号:2015CB351902)资助项目

摘　　要：随着外延剥离技术和转印技术的发展,柔性无机半导体集成器件引起人们的广泛关注.柔性无机发光二级管(LED)的研制是高精度转印技术和应用于生物传感的柔性混合集成技术的迫切需求.薄膜发光二级管(TF-LEDs)的电流扩展和热管理是研制TF-LEDs性能的关键.该文采用光刻胶微支撑结构,制备了两种结构的TF-LEDs,并将其转印到柔性衬底聚二甲基硅氧烷(PDMS)上,测试TF-LEDs的电学特性.采用二维有限元模拟仿真,综合考虑复合机制、晶格温度等对LEDs电学特性的影响,分析了条形电极结构TF-LEDs和环形电极结构TF-LEDs的电流扩展问题,说明环形电极结构TF-LEDs电流分布均匀性好,自发热效应较小;在柔性衬底上,可以在相对较大的功率下连续工作而不会因为温度过高而造成器件损坏.The development of science and technology puts forward new requirements to electronic and optoelectronic semiconductor devices, such as flexibility, temperature and bio-compatibility. Great advances in the technology of epitaxial lift-off and transfer printing, have the potential to create new engineering opportunities and application possibilities for Light-Emitting Diodes（LEDs） technologies. Researchers strive to make the device flexible and stretchable, so that it can be integrated into any surface, such as deformable display, wearable device, lighting and biomedical devices. In this paper, we utilize micro photoresist anchors to fabricate the two kinds of thin-film LEDs, LEDs with strip electrodes and LEDs with square ring electrodes, respectively. Afterwards, we transfer them to the poly（dimethylsiloxane）（PDMS） succeeding in making flexible inorganic LEDs. We also test the electrical characteristics of TF-LEDs to compare with the result of simulation. The current spreading and thermal effect are the key to the performance of thin-film LEDs（TF-LEDs）. Using 2D finite element simulation, take recombination and lattice temperature effect on TF-LEDs electrical characteristics into account, we analyze the current spreading in LED1 with strip electrodes and LED2 with square ring electrodes. We find that LED2 s exhibit a better current distribution uniformity of TF-LEDs and lower local highest temperature compared to LED1 s in flexible substrates. Because of the improved current spreading and better thermal management, TF-LEDs with square ring electrodes can work continuously under relatively large power without worrying about the damage caused by high temperature. This result has a guiding significance for the use of TF-LEDs on flexible substrates.

关 键 词：薄膜LEDs 电流扩展 热效应 柔性 

分 类 号：TN312.8[电子电信—物理电子学]