基于MEMS技术的集成LED微阵列器件研究

发布时间：2018-04-12 12:17

本文选题：微型LED阵列 + AlGaInP芯片　；参考：《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

【摘要】：LED以亮度高、功耗低、响应速度快及性能稳定可靠等优点在照明、显示、航空航天、医疗、生物基因工程及通讯网络等领域得到广泛的应用。近年来,为满足商业与科技领域等对微显示、高分辨率微型LED器件的迫切需求,国内外纷纷开展了集成LED微阵列器件的研究。本论文主要研究了以Al Ga In P-LED外延片为制作LED微阵列器件的基本材料,采用MEMS技术和半导体工艺技术等完成了高密度、高分辨率微型LED阵列器件的制作。该LED微阵列器件具有像素尺寸可控、集成度高等优点。本论文的工作主要包括以下四个部分:1.研究了将LED芯片阵列化后排列时光源发光强度及接收面光照度的变化。将300μm×300μm LED芯片阵列化分割为间隔为20μm的3×3个80μm×80μm的像素,阵列化后,总饱和光输出功率是阵列化前的5.19倍,最大注入电流提高近7倍。表明阵列可以注入更大的电流和输出更高的饱和光功率。此外,当采用多颗阵列化后的LED芯片形成的芯片组的间距为最大平坦条件dmax时,接收面上照度均匀性最佳;芯片组数越多,接收面上均匀照度的面积越大。同样以dmax排列照明时,9颗300μm×300μm的芯片阵列化为9个80μm×80μm的LED芯片与9颗未阵列化的300μm×300μm芯片相比,接收面上的光照度均匀性不变,照度值提高了3倍。2.针对以Al Ga In P为基本材料设计的微型LED阵列器件像素内部电流密度分布不均匀问题,采用Silvaco软件分析了电极结构对电流密度分布的影响。在保证电极覆盖发光单元面积不变的条件下,设计了四种插指状阳极电极结构。对四种阳极电极结构下像素有源层内部的电流密度分布进行计算分析,得到5插指结构下像素内部的电流密度分布最均匀。此外,在稳定的驱动环境下,相比于其它电极结构,5插指电极结构下像素的饱和光输出功率密度最高,约为50W/cm2;随注入电流的增加,该电极结构像素内部结温变化最小。3.设计了Al Ga In P-LED微阵列器件的结构与工艺步骤,并完成了器件制作。在器件制作中,采用MEMS技术在通用Al Ga In P-LED芯片上制作出深宽比为2:1的隔离沟道,实现了高密度LED像素的集成;分别通过真空填充聚酰亚胺(PI)及跨沟道PI膜两种方案完成了电极介质桥的制作;通过腐蚀或剥离技术制作了LED阵列阳极电极;采用机械与化学减薄技术进行衬底减薄,实现了LED阵列的像素分离。测试得到像素开启电压为1.7V,当衬底厚度为150μm,注入电流为10m A时,像素的光输出功率为326μW.4、针对柔性LED阵列等特殊应用对LED微阵列器件宽单元间距的需求,设计并实验验证了多次掩膜腐蚀法与平面间隔腐蚀法实现宽间距的方案。
[Abstract]:LED has been widely used in lighting, display, aerospace, medical, biogenetic engineering and communication networks due to its advantages of high brightness, low power consumption, fast response speed and stable and reliable performance.In recent years, in order to meet the urgent needs of micro display and high resolution micro LED devices in commercial and scientific fields, the research of integrated LED microarray devices has been carried out at home and abroad.In this paper, the fabrication of high density and high resolution LED microarray devices using Al Ga in P-LED epitaxial wafer as the basic material is studied. The fabrication of high density and high resolution microarray devices is accomplished by using MEMS technology and semiconductor technology.The LED microarray device has the advantages of controllable pixel size and high integration.The work of this thesis mainly includes the following four parts: 1.The changes of the luminous intensity and the light intensity of the receiving surface during the array of LED chips were studied.The array of 300 渭 m 脳 300 渭 m LED chips is divided into 3 脳 3 80 渭 m 脳 80 渭 m pixels with an interval of 20 渭 m. The total output power of saturated light is 5.19 times of that before the array, and the maximum injection current is increased nearly 7 times.It shows that the array can inject more current and output higher saturated optical power.In addition, when the spacing of the chipset formed by the array of LED chips is the maximum flat condition dmax, the illumination uniformity on the receiving surface is the best, and the area of uniform illumination on the receiving surface increases with the increase of the number of chipsets.The illumination uniformity on the receiving surface of 9 LED chips with 80 渭 m 脳 80 渭 m and 9 unarrayed LED chips with #number0# 渭 m 脳 300 渭 m is increased by 3 times and the illumination value is increased by 3 times.Aiming at the non-uniform distribution of current density in pixels of miniature LED array devices designed with Al Ga in P as the basic material, the effect of electrode structure on current density distribution was analyzed by Silvaco software.Four kinds of intercalated anode structures are designed under the condition that the electrode covers the same area of the luminescent cells.The distribution of the current density in the active layer of the pixel is calculated and analyzed under four kinds of anode electrode structures. The results show that the distribution of the current density in the pixel is the most uniform under the five-point structure.In addition, under stable driving environment, the output power density of saturated light is the highest, about 50 W / cm ~ 2, compared with that of other electrode structures, which is about 50 W / cm ~ (2), and the minimum change of junction temperature of pixels in the electrode structure is .3with the increase of injection current.The structure and process of Al Ga in P-LED microarray devices are designed and fabricated.In the fabrication of the device, the isolation channel with the aspect ratio of 2:1 is fabricated on the universal AlGa in P-LED chip by MEMS technology, and the integration of high density LED pixels is realized.The electrode dielectric bridge was fabricated by vacuum filling polyimide (Pi) and cross-channel Pi film, the LED array anode electrode was fabricated by etching or stripping technology, and the substrate thinning was performed by mechanical and chemical thinning techniques.The pixel separation of LED array is realized.When the substrate thickness is 150 渭 m and the injection current is 10 Ma, the output power of the pixel is 326 渭 W. 4. For special applications such as flexible LED array, the wide cell spacing of LED microarray devices is required.The scheme of multiple mask etching and plane interval corrosion is designed and verified experimentally.
【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

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