硅薄膜导热系数微尺度效应的临界尺寸  

Critical Size for Microscale Effect of Silicon Film Thermal Conductivity

作　　者：苏高辉[1,2] 杨自春[1,2] 孙丰瑞[2] 

机构地区：[1]海军工程大学舰船高温结构复合材料研究室,武汉430033 [2]海军工程大学动力工程学院,武汉430033

出　　处：《纳米技术与精密工程》2014年第3期176-181,共6页Nanotechnology and Precision Engineering

基　　金：总装十二五预研基金资助项目(401030603)

摘　　要：基于灰介质假设及拟合的色散关系，采用蒙特卡洛方法对微纳米硅薄膜内的声子热输运特性进行了模拟．将3μm厚的硅薄膜导热系数的计算结果与文献结果进行了对比，二者吻合较好．分析了厚度对薄膜内温度场及导热系数的影响．结果表明，当厚度小于某一尺度时，薄膜导热系数会随着厚度的减小而降低，呈现尺度效应；薄膜内温度场也不再是线性分布，而是在边界处呈现阶跃特性，且随着厚度减小，温度阶跃增大．基于该方法求得了100～400K温度区间内，硅薄膜法向导热系数出现明显尺度效应的临界尺寸．计算发现，随着温度的升高，临界尺寸变化范围很大，平均温度为100K时，临界尺寸约为50μm，平均温度为400K时，临界尺寸约为2．5μm，前后相差了一个数量级．Based on the gray media approximation and the fitted dispersion relation, the phonon heat transport in micro-nano silicon films was simulated with the Monte Carlo method. The predicted thermal conductivity （TC） of silicon film with 3 μm thickness was in good agreement with literature results. The effect of the thickness on the temperature field and cross-plane TC of the silicon films was analyzed. The results show that when the thickness is less than a certain scale, the TC of the film decreases with the de- crease in thickness, which exhibits scale effect; the temperature field is not in linear distribution, but shows discontinuous characteristics at the boundary, and as the thickness decreases, the temperature dis- continuity degree increases. The critical size at which TC begins to show obvious scale effect was obtained at the temperature range between 100 K and 400 K. Calculated results show that as the temperature in- creases, the critical size decreases sharply. When the average temperature is 100 K, the critical size is about 50 μm; when the average temperature is 400 K, the critical size is about 2.5 μm, which shows a difference of an order of magnitude.

关 键 词：硅薄膜 蒙特卡洛方法 导热系数 声子热输运 尺度效应 

分 类 号：TB383.2[一般工业技术—材料科学与工程]