湿法表面粗化提高倒装AlGaInP LED外量子效率

介绍了一种利用盐酸、磷酸混合液对不同Al组分(AlxGa1-x)0.5In0.5P的选择性腐蚀特性对倒装AlGaInP红光LED进行表面粗化的方法。通过向粗化层GaInP加入适量的Al,在Al组分为0.4时,利用体积比为1∶10的HCl∶H3PO4可以得到横向尺寸约为60nm,纵向尺寸约为150nm的最有利于出光的类三角圆锥型表面结构。器件测试结果表明,在20mA注入电流下,器件外量子效率比粗化前提高了80%。     

表面增透结构AlGaInP LED的研究

A kind of AlGaInP light emitting diode （LED） with surface anti-reflecting structure has been introduced to solve the problems of low light efficiency and restricted luminous intensity. The new structure can be demonstrated theoretically and experimentally, and LEDs with the new structure have higher on-axis luminous intensity and larger saturation current than conventional LEDs and LEDs with ITO film only, which is caused by higher external quantum efficiency and also higher internal quantum efficiency. The new LEDs are especially suitable for working at large injected currents.     

AlGaInP系LED的表面纳米级粗化以及光提取效率提高

分析了常规AlGaInP系发光二极管（LED）光提取效率低的主要原因,半导体的折射率与空气折射率相差很大,导致全反射使有源区产生的光子绝大部分不能通过出光面发射到体外。通过在LED出光层采用纳米压印技术引入表面纳米结构,以改变光子的传播路径,从而使得更多的光子能够发射到体外。理论分析与实验结果表明,与常规平面结构相比,...     

GaAs基AlGaInP LED的研究和进展

探讨了GaAs基AlGaInP LED的最新研究与进展,介绍了AlGaInP红光LED外延材料的能带结构和基本的外延层结构以及限制外量子效率的问题,探讨了几种高效率的LED器件结构设计。着重介绍了目前一些外量子效率比较高的LED器件的制作方法以及一些提高外量子效率的AlGaInP LED器件结构,最后探讨了AlGaInP LED在作为固体光源发展过程中仍然需要面对的挑战。     

CMP工艺参数对AlGaInP基LED衬底转移的影响

以GaP/Al₂O₃/SiO₂引导式出光结构作为芯片键合层,通过化学机械抛光工艺减少AlGaInP基Mini-LED衬底转移过程中出现的外延层空洞,提高芯片制备工艺良率。以材料去除速率和表面粗糙度作为技术评价指标,基于单因素实验结果对抛光压力、抛光头转速、抛光盘转速、抛光液流速四个影响化学机械抛光工艺的因素展开L₉（3～4）的正交实验,实验结果表明：在抛光头转速75 r/min、抛光盘转速80 r/min、抛光压力8 kPa、抛光液流速100 mL/min条件下,材料去除速率为83.12 nm/min,表面粗糙度最低为0.477 nm,采用优化后的工艺条件能够获得高质量的GaAs键合表面,有效减少外延空洞,提高制备良率。     

垂直结构LED和倒装结构LED的发光特性研究

研究了1.16 mm GaN基蓝光芯片的垂直封装结构LED和倒装封装结构LED在驱动电流达到和超过工作电流350mA的发光特性和变化趋势.随着驱动电流的逐渐增大,与垂直结构LED相比,倒装结构LED光通量的饱和电流值增加350mA,在1 200 mA电流时的光通量高出25.9％,色温的异常电流值增加了400 mA,发光效率平均提高81 m/W.实验结果表明,倒装结构LED具有更高的抗大电流冲击稳定性和光输出性能,可有效提高LED在实际应用中使用寿命.     

倒装芯片与表面贴装工艺

<正> 1 引言 蜂窝电话,个人数码助理机(PDA),数码相机等各种消费类电子产品已逐渐变得更小,反应更为迅速,同时智能化的程度也越来越高。因而,电子封装及组装工艺必须跟上这一快速发展的步伐。随着材料性能、设备及工艺水平的不断提高,使得越来越多的电子制造服务公司(EMS)不再满足于常规的表面贴装工艺(SMT),而不断尝试使用新型的组装工艺,这其中就包括倒装芯片(FC)。     

GaP表面粗化对AlGaInP发光二极管光电特性的影响

采用湿法溶液粗化AlGaInP基红光LED表面GaP层 ,并在粗化后的GaP表面沉积ITO,研究了粗化时间对GaP表面形貌的影响,并利用SEM、半导 体 芯片测试机、X射线衍射仪、X射线光电子能谱对LED器件表面形貌、光电特性曲 线、界面晶向、元素特性进行表征,比较了粗化前后的LED亮度和光电特性变 化。测试结果表明:采用HIO₄、I₂、HNO₃系列粗化液在室温、粗化时间为30 S 时,有效增加了光在通过GaP面与ITO界面时的出光角度,使AlGaInP发光二极管 的发光效率提高21.4%,同时引起界面处的缺陷密度升高,费米能级 远离价带,主波长蓝移0.36 nm,正向电压上升0.04 V。     

AlGaInP LEDs with surface anti-reflecting structure

he new LEDs are especially suitable for working at large injected currents.     

表面粗化提高倒装AlGaInP发光二极管的光提取效率

对发光二极管进行表面粗化能够大幅度的提高其光提取效率。利用晶片键合技术并采用湿法刻蚀的办法粗化n面AlGaInP表面制作了一种带表面粗化的倒装薄膜发光二极管。刻蚀后的表面形貌呈现金字塔状。270μm x 270μm管芯裸装在TO-18金属管座上,在20mA的注入电流下,粗化了的LED-I光强达到了315mcd,输出光功率达到了4.622mW,比没有粗化的LED-II的光功率高1.7倍。光功率增加的原因在于粗化后形成的这种金字塔状表面,其不但减少了背部镜面系统和半导体-空气接触面的反射,而且能有效的将光从LED中散射出去。     

Improved light extraction of wafer-bonded AIGaInP LEDs by surface roughening

By using the wafer bonding technique and wet etching process, a wafer bonded thin film AlGaInP LED with wet etched n-AlGaInP surfaces was fabricated. The morphology of the etched surface exhibits a pyramid-like feature. The wafer was cut into 270× 270 μm2 chips and then packaged into TO-18 without epoxy resin. With 20-mA current injection, the light intensity and output power of LED-I with surface roughening respectively reach 315 mcd and 4.622 mW, which was 1.7 times higher than that of LED-II without surface roughening. The enhancement of output power in LED-I can be attributed to the pyramid-like surface, which not only reduces the total internal reflection at the semiconductor-air interface but also effectively guides more photons into the escape angle for emission from the LED device.     

隧道再生双有源区AlGaInP发光二极管提取效率的计算

建立了发光二极管提取效率的理论计算模型,分析了影响隧道再生双有源区AlGaInP发光二极管提取效率的主要因素,包括从出光表面出射的光、体内的光吸收损耗、衬底对光的吸收损耗、金属电极对光的吸收损耗,模拟计算了隧道再生双有源区AlGaInP发光二极管的提取效率,计算得到隧道再生双有源区AlGaInP LED管芯的上有源区和下有源区提取效率分别为5．24％和9．16％。     

Thermal measurements and analysis of AlGaInP/GaInP MQW red LEDs with different chip sizes and substrate thicknesses

Thermal properties of AlGaInP/GaInP MQW red LEDs are investigated by thermal measurements and analysis for different chip sizes and substrate thicknesses. To extract the thermal resistance (R_th), junction temperature (T_j) is experimentally determined by both forward voltage and electroluminescence (EL) emission peak shift methods. For theoretical thermal analysis, thermal parameters are calculated in simulation using measured heat source densities. The T_j value increases with increasing the injection current, and it decreases as the chip size becomes larger. The use of a thin substrate improves the heat removal capability. At 450 mA, the T_j values of 315 K and 342 K are measured for 500 × 500 μm² LEDs with 110 μm and 350 μm thick substrates, respectively. For 500 × 500 μm² LEDs with 110 μm thick substrate, the R_th values of 13.99 K/W and 14.89 K/W are obtained experimentally by the forward voltage and EL emission peak shift methods, respectively. The theoretically calculated value is 13.44 K/W, indicating a good agreement with the experimental results.     

薄膜AlGaInP发光二极管中不同反光镜的研究

本文计算了GaP/Au 反光镜, GaP/SiO2/Au 三层ODR and GaP/ITO/Au 三层ODR的反射率随角度的变化值。制作了GaAs衬底的AlGaInP LED,Au反光镜、SiO2 ODR和ITO ODR的薄膜AlGaInP LED。在20mA下,四种样品光输出功率分别为1.04mW, 1.14mW, 2.53mW and 2.15mW。制作工艺退火后,Au扩散使Au/GaP反光镜的反射率降至9％。1/4波长的ITO和SiO2透射率不同造成了两种薄膜LED光输出功率不同。ITO ODR中加入Zn可以大大降低LED的电压,但并不影响LED的光输出。     

晶圆键合技术在LED应用中的研究进展

简要介绍了晶圆键合技术在发光二极管(LED)应用中的研究背景,分别论述了常用的黏合剂键合技术、金属键合技术和直接键合技术在高亮度垂直LED制备中的研究现状,包括它们的材料组成和作用、工艺步骤和参数以及优缺点.其中,黏合剂键合是一种低温键合技术,且易于应用、成本低、引入应力小,但可靠性较差;金属键合技术能提供高热导、高电导的稳定键合界面,与后续工艺兼容性好,但键合温度高,引入应力大,易造成晶圆损伤;表面活化直接键合技术能实现室温键合,降低由于不同材料间热失配带来的负面影响,但键合良率有待提高.     

Water bonding of 50-mm-diameter mirror substrates to AlGaInP light-emitting diode wafers

The feasibility of bonding 50-mm-diameter Si with a Au/AuBe mirror to AlGaInP light-emitting diode (LED) wafers is demonstrated. Wafer bonding over the entire wafer area is achieved while the metallic mirror still maintains high reflectivity. Using this technique, the mirror-substrate AlGaInP LEDs are fabricated across an entire 50-mm wafer. The test data show that 98% of the dice with operating voltages <2.2 V at 20 mA and 85% of the dice with luminous intensity in the 130∼140 mcd region. The wafer-bonded mirror-substrate LED lamps operating at 626 nm can emit 3 lm at 20 mA with a forward voltage of 2 V, corresponding to a luminous efficiency of 74 lm/W. Moreover, they present a peak power efficiency of 21% with 4 mW output at 10 mA (1.9 V). Essentially no degradation is observed for these LEDs after 2000 h stress at 80°C and 50 mA (55.6 A/cm²). The results indicate the mirror-substrate AlGaInP LEDs of highly reliable and efficient performance.