新型全方位反射铝镓铟磷薄膜发光二极管

提出了一种新型全方位反射铝镓铟磷(AlGaInP)薄膜发光二极管(LED)的结构和制作工艺，在这个结构里应用了低折射率的介质和高反射率的金属联合作为反光镜.用金锡合金(80Au20Sn，重量比)作为焊料把带有反光镜的AlGaInP LED外延片倒装键合到GaAs基板上(RS-LED)，去掉外延片GaAs衬底，把被GaAS衬底吸收的光反射出去.通过与常规AlGaInP 吸收衬底LEDs(AS-LED)和带有DBR的AlGaInP 吸收衬底LEDs(AS-LED(DBR))电、光特性的比较，证明新型全方位反射AlGaInP薄膜LED结构能极大提高亮度和效率.正向电流20mA时，RS-LED的光输出功率和流明效率分别是AS-LED的3.2倍和2.2倍，是AS-LED(DBR)的2倍和1.5倍.RS-LED(20mA下峰值波长627nm)的轴向光强达到194.3mcd，是AS-LED(20mA下峰值波长624nm)轴向光强的2.8倍，是AS-LED(DBR)(20mA下峰值波长623nm)轴向光强的1.6倍. 关键词： 铝镓铟磷 薄膜发光管 全方位反射镜 发光强度

A novel AlGaInP thin-film light emitting diode with omni directional reflector

A novel AlGaInP thin-film light emitting diode (LED) with omni directional reflector structure was proposed, the corresponding fabrication process was developed. This reflector is realized by the combination of a low-refractive-index dielectric layer and a high reflectivity metal layer. The AlGaInP LED layers with dielectric-metal reflector is invertedly bonded to the GaAs submount by using 80Au-20Sn (wt%) alloy as a solder (Reflector-Submount, RS-LED), and then GaAs substrate is removed. The light that would otherwise be absorbed by the GaAs substrate is reflected by the high reflectivity dielectric-metal reflector. The optical and electrical characteristics of the RS-LED are presented and compared with the conventional AlGaInP absorbing substrate (AS) LED and AlGaInP absorbing substrate LED with distributed Bragg reflectors (DBR). A great improvement in the brightness and efficiency is observed. It is shown that the light output and lumen efficiency from the RS-LED at forward current 20mA exceed those of AS-LED by about a factor of 2.2 and 1.2, respectively, and ～2× the light output of AS-LED (DBR) and ～1.5× the lumen efficiency of AS-LED　(DBR) were achieved. 194.3mcd luminous intensity from the RS-LED (at 20mA, peak wavelength 627nm) could be obtained under 20mA injection, which is 2.8 and 1.6 times higher in luminous intensity than the AS-LED (at 20mA, peak wavelength 624nm) and AS-LED(DBR) (at 20mA, peak wavelength 623nm), respectively.