微型倒装AlGaInP发光二极管阵列器件的光电性能

Photoelectric Characteristics of Micro Flip-Chip AlGaInP Light Emitting Diode Array

为进一步提高红光微型发光二极管(LED)阵列器件的能量利用效率,对倒装AlGaInP LED阵列器件的光电性能进行研究。首先,测试对比了垂直型和倒装型AlGaInP LED两种芯片结构的出光性能,表明倒装型LED具有更高的出光功率。其次,建立了倒装型LED阵列出光功率模型,计算得到了出光功率与环境温度、基底热阻的关系:随基底热阻增大、环境温度升高,AlGaInP LED阵列器件的出光功率逐渐降低,出光饱和处对应的注入电流前移,光电性能逐渐下降。然后,采用转印法制备了6×6倒装AlGaInP LED阵列,测试结果表明,理论与实测结果较为一致。最后,利用有限元软件计算分析了Cu和聚二甲基硅氧烷(PDMS)这两种常见基底的热阻随环境、结构变化的数值关系。结果显示:Cu基底的散热较为均匀,优化基底结构或增加空气对流速率,对Cu基底热阻值的改变相对较小;PDMS材料的散热均匀性相对较差,通过优化基底结构、增大空气对流速率可以有效降低基底热阻,改善微型LED阵列器件的光电性能。

In order to improve the energy utilization of red LED array devices,we study the photoelectric characteristics of flip-chip AlGaInP-based light emitting diode（LED）array device.Firstly,the light output power characteristics of AlGaInP-based LED with vertical type and flip-chip type structures are tested and compared with each other.The results show that the light output power of flip-chip LED is higher than that of the vertical LED.Then,a model to calculate the output power of flip-chip LED array is proposed,which is used to calculate the relationship between light output power,ambient temperature and base thermal resistance.The results reveal that with the increase of the base thermal resistance and ambient temperature,the output power of the LED array device decreases,the injection current at saturation shifts forward,and the photoelectric performance of LED array decreases.The 6×6 flip-chip AlGaInP-based LED array device is prepared using the transfer method.The testing results are consistent with the theoretical predictions.Finally,the numerical relationships between the thermal resistance of Cu and polydimethylsiloxane（PDMS）with different basement structures and ambient conditions are analyzed by finite element method.The results show that the heat dissipation capacity of Cu is relatively uniform and its thermal resistance is not sensitive to the structure and the air convection rate.However,for PDMS materials,the thermal resistance is relatively large and can be effectively reduced by optimizing its structure and increasing the air convection rate,thereby improve the photoelectric performance of the micro LED array device.