功率型发光二极管芯片的温度场与应力场

发光二极管(LED)的结点温度和应力分布对它的发光效率、可靠性和寿命有着至关重要的影响。为了优化器件的性能,该文利用有限元方法对功率型LED芯片在不同输入功率、基板材料、换热条件下的温度和热应力进行了模拟与分析。结果表明,目前广泛应用的Sapphire基板效果不是很好,如果能减小晶格不匹配的影响,采用硅基板是较好的选择。当基板导热系数、换热系数大于一定值后,单纯的改进基板的导热系数或强化基板换热,对提高器件的性能已经没有明显的效果。

Temperatures and thermal stresses in high-power light emitting diodes

Die temperatures and thermal stresses can have significantly influence the efficiency,reliability,and late time of light emitting diodes(LED).To optimize the performance of these devices,the temperatures and thermal stresses in high-power light emitting diodes were numerically investigated using the finite element method for various powers and various thermal conductivity and substrate heat transfer coefficients.The results show that the device performance can be significantly improved by replacing the prevailing sapphire substrate with other high conductivity substrates,especially a Si substrate,if the lattice mismatch effect can be eliminated.Extremely high thermal conductivities and heat transfer coefficients contribute little to further reductions of the thermal stresses and die temperatures.