Thermal conductivity modeling of GaN films
نویسندگان
چکیده
准确预测GaN半导体材料的热导率对GaN基功率电子器件的热设计具有重要意义. 本文基于第一性原理计算和经典Debye-Callaway模型,通过分析和完善Debye-Callaway模型中关于声子散射率的子模型, 建立了用于预测温度、同位素、点缺陷、位错、薄膜厚度、应力等因素影响的GaN薄膜热导率的理论模型. 具体来说, 对声子间散射项和同位素散射项基于第一性原理计算数据进行了系数拟合, 讨论了两种典型的处理点缺陷和位错散射的散射率模型, 引入了应用抑制函数描述的各向异性边界散射模型,并对应力的影响进行了建模. 热导率模型预测值和文献中典型实验数据的对比表明, 基于第一性原理计算数据拟合的热导率模型和实验测量值总体符合较好, 300 K温度附近热导率数值及其随温度变化的趋势存在20%左右的偏差. 结合实验数据和热导率模型进一步确认了第一性原理计算会高估同位素散射的影响, 给出了薄膜热导率随薄膜厚度、位错面密度、点缺陷浓度的具体变化关系, 同位素和缺陷散射会减弱薄膜热导率的尺寸效应, 主要体现在100 nm附近及更小的厚度范围.
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ژورنال
عنوان ژورنال: Chinese Physics
سال: 2021
ISSN: ['1000-3290']
DOI: https://doi.org/10.7498/aps.70.20201611