插指型SiO_2电流阻挡层对大功率LED外量子效率的影响

Effect of Interdigitated SiO_2 Current Blocking Layer on External Quantum Efficiency of High Power LEDs

为了改善蓝光大功率LED芯片p电极处的电流拥挤现象,提高大功率LED芯片的外量子效率,在ITO透明导电层与p-GaN间沉积插指型SiO_2电流阻挡层。采用等离子体增强化学气相沉积的方法沉积SiO_2薄膜,再经过光刻和BOE湿法刻蚀技术制备插指型SiO_2电流阻挡层。采用SimuLED仿真软件分析插指型SiO_2电流阻挡层对大功率LED芯片电流扩展性能的影响,研究插指型SiO_2电流阻挡层对大功率LED芯片外量子效率的影响。结果发现,插指型SiO_2电流阻挡层结构可以有效改善p电极附近的电流拥挤现象。与没有沉积插指型SiO_2电流阻挡层的大功率LED芯片相比,光输出功率得到显著的提高。在350 mA的输入电流下,沉积插指型SiO_2电流阻挡层后的大功率LED芯片的外量子效率提高了18.7%。

In order to alleviate current crowding around p-electrode of high power blue light-emitting diodes （LEDs） and improve its external quantum efficiency （EQE）, a SiO2 current blocking layer （CBL） was deposited between ITO transparent conductive layer and p-GaN by plasma enhanced chemical vapor deposition （PECVD）. An interdigitated SiO2 CBL pattern was then fabricated by photolithography and BOE wet etching process. The effect of interdigitated SiO2 CBL on the current spreading performance of high power LED was analyzed using commercial SimuLED package. It is found that the current crowding around the p-electrode is effectively alleviated by employing the in- terdigitated SiO2 CBL. Comparing with the high power LED without interdigitated SiO2 CBL, the light output power is significantly improved. At 350 mA injection cun-ent, the external quantum effi- ciency of the high power LED with interdigitated SiO2 CBL is 18.7% higher than that of LED with- out interdigitated SiO2 CBL.