柔性AlGaInP-LED微阵列器件设计及制作技术研究

发布时间：2018-01-28 09:31

本文关键词： LED微阵列柔性器件 MEMS 力学特性热耗散　出处：《中国科学院长春光学精密机械与物理研究所》2017年博士论文　论文类型：学位论文

【摘要】：随着工艺技术水平的发展和应用需求的不断提高,对于无机半导体LED的研究趋于微型化、阵列化、集成化及柔性化。柔性光电子器件的研究扩展了传统无机半导体光电器件的应用领域,具有柔性化及集成化优势的柔性LED微阵列引起了国内外研究团队广泛关注。柔性LED微阵列通过对器件结构的特殊设计和制备工艺的选择,克服了机械性能的限制,器件具备柔韧性及适应性,具有可挠性好、可贴附在任意曲面或不规则物体表面的特点。本论文以通用型红光AlGaInP-LED外延片作为核心发光材料,在LED发光机理研究的基础上开展了柔性LED微阵列器件的研究,成功设计和制作了柔性LED微阵列器件样品,并进一步研究了柔性LED微阵列器件的散热问题。具体研究内容包括:1.重点总结了LED发光的基本机理、LED的效率评价、效率衰退及其影响因素、LED的电流-电压特性的内部机制及其等效电路;讨论了柔性衬底对LED发光的影响因素。2.比较了聚酰亚胺、聚二甲基硅氧烷、PET等柔性材料的特点,选择了聚二甲基硅氧烷作为柔性LED微阵列的连接材料,聚酰亚胺作为柔性基底材料。设计了多层堆叠式垂直柔性LED微阵列器件的基本结构,计算了柔性基底和包覆层的厚度,并分析了器件在弯曲状态下的力学特性;3.优化设计了连接电极结构,并分析了电极结构的可靠性和疲劳性,提出了多通路电极结构。多通路抑制了应变在局部区域的集中,使应力分布分散化,其伸展性和弯曲性相比于等宽度的直线型电极及单通路电极都有了显著提升;4.设计了基于MEMS技术的柔性AlGaInP-LED微阵列的制作工艺流程,重点研究了湿法化学腐蚀、ICP刻蚀、金属沉积、化学机械减薄等工艺方法,完成了高深宽比隔离沟槽的制作、Ga As衬底的减薄、像素间连接电极的和接触点阵列的制作,制备了聚酰亚胺基底的8×8柔性AlGaInP-LED微阵列器件样品;5.分析了LED在光电转换过程的能量损失,并结合柔性LED微阵列器件光电性能的测试结果,分析了影响柔性LED微阵列器件热耗散的因素。聚合物基底的热导率决定了器件的整体是散热能力;厚度为500μm-1000μm的柔性基底有利于热量有效传导;增大LED像素的间距可以防止热量在局部区域的快速积聚;在柔性基底上制作微结构是增强柔性LED微阵列器件热耗散的有效手段。
[Abstract]:With the development of process technology and the improvement of application demand, the research of inorganic semiconductor LED tends to be miniaturized and arrayed. The research of flexible optoelectronic devices extends the application field of traditional inorganic semiconductor optoelectronic devices. Flexible LED microarrays with flexible and integrated advantages have attracted wide attention of domestic and foreign research teams. Flexible LED microarrays are selected through the special design of device structure and fabrication process. Overcome the limitations of mechanical properties, the device has flexibility and adaptability, flexible and good. In this thesis, the general red AlGaInP-LED epitaxial wafer is used as the core luminescent material. Based on the study of LED luminescence mechanism, the flexible LED microarray devices were studied, and the samples of flexible LED microarray devices were designed and fabricated successfully. Furthermore, the heat dissipation of flexible LED microarray devices is studied. The specific research contents include: 1.The basic mechanism of LED luminescence is summarized, including efficiency evaluation, efficiency decline and its influencing factors. The internal mechanism and equivalent circuit of current-voltage characteristic of LED; The influence factors of flexible substrates on LED luminescence are discussed. 2. The characteristics of polyimide, polydimethylsiloxane LED and other flexible materials are compared. Polydimethylsiloxane was selected as the joining material of flexible LED microarray and polyimide as flexible substrate. The basic structure of multilayer stacked vertical flexible LED microarray device was designed. The thickness of flexible substrate and coating layer is calculated, and the mechanical properties of the device under bending state are analyzed. 3. The connection electrode structure is optimized, and the reliability and fatigue of the electrode structure are analyzed. The multi-channel electrode structure is proposed, which can restrain the concentration of strain in the local region and make the stress distribution disperse. The extensibility and curvature of the electrode are significantly improved compared with the linear electrode and single-channel electrode of equal width. 4. The fabrication process of flexible AlGaInP-LED microarray based on MEMS technology is designed, with emphasis on wet chemical etching and metal deposition. By chemical and mechanical thinning, the fabrication of high aspect ratio isolation grooves has been completed. The fabrication of GaAs substrates, interpixel connected electrodes and contact point arrays has been carried out. The samples of 8 脳 8 flexible AlGaInP-LED microarray devices on polyimide substrate were prepared. 5. The energy loss of LED in the photoelectric conversion process is analyzed, and the test results of the photoelectric performance of flexible LED microarray devices are given. The factors influencing the thermal dissipation of flexible LED microarray devices are analyzed. The thermal conductivity of polymer substrate determines the overall heat dissipation capability of the devices. A flexible substrate with a thickness of 500 渭 m to 1000 渭 m is conducive to effective heat conduction. Increasing the spacing of LED pixels can prevent the rapid accumulation of heat in the local area. Fabrication of microstructures on flexible substrates is an effective means to enhance thermal dissipation of flexible LED microarray devices.
【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN312.8

【参考文献】