单晶硅薄膜法向热导率的分子动力学模拟  

Molecular dynamics simulation on the out-of plane thermal conductivity of single-crystal silicon thin films

作　　者：吴国强[1] 孔宪仁[1] 孙兆伟[1] 赵丹[1] 张伟清[1] 

机构地区：[1]哈尔滨工业大学卫星技术工程研究所,哈尔滨150001

出　　处：《哈尔滨工业大学学报》2007年第9期1366-1369,共4页Journal of Harbin Institute of Technology

基　　金：国家重点基础研究发展规划资助项目(5131201)

摘　　要：结合卫星“微型核”的特点,用分子动力学模拟的方法研究了硅晶体的热导率与其厚度的依变关系.采用Tersoff势能函数,用非平衡分子动力学方法（NEMD）研究了温度为400 K和500 K,厚度为2.715-10.86 nm的单晶硅薄膜的热导率.模拟结果表明：在温度为400 K和500 K时,薄膜热导率的计算值均随厚度的增加而增加,并显著小于体硅的实验值,在模拟范围内法向热导率与薄膜厚度呈近视线性关系.模拟结果表现出明显的尺寸效应.厚度为2.715 nm和8.145 nm的单晶硅薄膜的热导率随着温度的升高反而下降,且厚度越大,下降趋势越明显.Combining the characteristic of satellite ＂minisize nucleus＂, molecular dynamics simulation was implemented to study the relationship of the thermal conductivity and thickness of silicon. The tersoff function and NEMD calculations were used to study the thermal conductrity of single crystal silicon films with a thickness of about 2. 715 - 10. 86 nm. The results of calculations demonstrate that in the case of 400 K and 500 K, thermal conductivity values of film are much lower than their bulk counterparts, the conductivity decreases with the film thickness decreasing, and the out-of plane thermal conductivity relates to film thickness linearly in the simulation range. The size effect on thermal conductivity is salient at simulative results. The film thermal conductivity of silicon crystal decreases with increasing the temperature at 2. 715 nm and 8. 145 nm thickness, and the descend tendency becomes more remarkable with the increasing of the thickness.

关 键 词：热导率 分子动力学 尺寸效应 纳米薄膜 

分 类 号：O484.5[理学—固体物理]