为了提高GaN基LED芯片的光提取效率, 以GaN基LED芯片为研究对象, 建立了在蓝宝石衬底出光面和外延生长面上具有半球型图形的LED倒装芯片模型, 并利用光学仿真软件对图形参数进行优化设计。实验结果表明: 在蓝宝石衬底的出光面和外延生长面双面都制作凹半球型图形对芯片光提取效率的提高效果最好, 并且当半球的半径为3 μm, 周期间距为7 μm时, GaN基LED倒装芯片的最大光提取效率为50.8%, 比无图形化倒装芯片的光提取效率提高了115.3%。

In order to improve the light extraction efficiency of GaN-based light-emitting diodes(LEDs), a model was built to optimize the double-sided hemispherical patterned sapphire substrate(PSS) for highly efficient flip-chip GaN-based light LEDs,and an optical simulation was conducted to study how light extraction efficiency changed with the change in the parameters of the unit hemisphere for flip-chip LEDs fabricated on hemispherical PSS. Results show that the light extraction efficiency of flip-chip LEDs can be enhanced by the optimized hemispherical PSS by over 50.8% and is approximately 115.3% higher than that of flip-chip LEDs with non-PSS when the radius is 3μm and the distance is 7μm. This results confirm the high efficiency and excellent capability of the optimized hemispherical PSS pattern to improve LED efficacy.