Thermal Analysis of InGaN/GaN Multiple Quantum Well Light Emitting Diodes with Different Mesa Sizes
Thermal Analysis of InGaN/GaN Multiple Quantum Well Light Emitting Diodes with Different Mesa Sizes
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DOI：
10.1143/jjap.49.04dg11
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发表时间：
2010-04
影响因子：
1.5
通讯作者：
H. Lee;J. Yu
中科院分区：
文献类型：
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作者：
H. Lee;J. Yu
本文从实验和理论上分析了不同台面尺寸的470nm InGaN/GaN发光二极管（led）的热特性，以实现高效散热。对于不同的台面尺寸，结温作为注入电流的函数通过二极管正向电压法测量。结温（Tj）随注入电流的增加而线性增加，随介面尺寸的减小而迅速上升。热参数，如结温、温度分布和热阻（Rth），通过热模拟获得，热源密度由测量的光电流电压数据确定，使用三维散热模型。在200 mA时，当450 ×450和250 ×250µm2时，led的Tj值理论上分别为392.7和578 K。由于结温和注入电流之间的线性关系，热阻几乎保持不变，并且随着台面尺寸的增加而减小，表明450 ×450µm2 LED的低Rth < 75 K/W。热模拟得到的Rth值与实验数据基本一致。采用导热系数相对较高的衬底也可以显著提高led的Rth。
We analyze experimentally and theoretically the thermal characteristics of 470 nm InGaN/GaN light emitting diodes (LEDs) with different mesa sizes for efficient heat dissipation. For various mesa sizes, the junction temperature is measured as a function of injection current by the diode forward voltage method. The junction temperature (Tj) increases linearly with injection current and it rises rapidly with the reduction in mesa size. The thermal parameters, such as the junction temperature, temperature profile, and thermal resistance (Rth), are obtained from thermal simulations with the heat source density, determined from the measured light–current–voltage data, using a three dimensional heat dissipation model. At 200 mA, the Tj values of LEDs are theoretically calculated as 392.7 and 578 K for 450 ×450 and 250 ×250 µm2, respectively. The thermal resistance is kept nearly constant due to a linear relationship between junction temperature and injection current and it is reduced as the mesa size increases, indicating a low Rth of < 75 K/W for 450 ×450 µm2 LED. The Rth values obtained by the thermal simulation are fairly consistent with the experimental data. The use of the substrate with a relatively high thermal conductivity can also improve significantly the Rth of LEDs.