对AlGaInP-LED微型阵列发光单元的内部自发热机制进行了分析, 并通过对具有回型上电极的发光单元的理论分析与计算, 得到了其内量子效率与注入电流的变化关系及器件温度与所加偏压的变化关系。为保证内量子效率取值范围大于85%, 得到了器件的最佳工作电流和最佳驱动电压范围以及微阵列各层结构在最佳驱动电压下的热阻分布。通过计算得出器件在2.2 V电压下, 从p-n结到外部环境的有效热阻为96.7 ℃/W。讨论了减小器件热阻的方法, 计算得出在理想情况下, 添加热沉结构后有效热阻降为30.6 ℃/W, 表明所设计的热沉结构对器件的散热起到了明显的改善作用。

The principle of self-heating effect of AlGaInP micro-LED cells was analyzed. By analyzing the temperature distribution of each cell with square-circle electrode, the relationships of the internal quantum efficiency vs. anode current and the lattice device temperature vs. anode voltage were got. Under 2.2 V driving voltage, the thermal impedance of each layer was calculated and the effective thermal impedance was obtained as 96.7 ℃/W. After adding heat-sink to the device, the thermal impedance of the device with heat-sink structure was as low as 30.6 ℃/W in ideal condition. The results show that the thermal performance can be improved obviously with the designed heat-sink structure.