Zhu Wenhui, Zheng Guang, Cao Sen, He Hu
Collge of Mechanical and Electrical Engineering, Central South University, Changsha, 410083, China.
State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha, 410083, China.
Sci Rep. 2018 Jul 12;8(1):10537. doi: 10.1038/s41598-018-28925-6.
Amorphous SiO (a-SiO) thin films are widely used in integrated circuits (ICs) due to their excellent thermal stability and insulation properties. In this paper, the thermal conductivity of a-SiO thin film was systematically investigated using non-equilibrium molecular dynamics (NEMD) simulations. In addition to the size effect and the temperature effect for thermal conductivity of a-SiO thin films, the effect of defects induced thermal conductivity tuning was also examined. It was found that the thermal conductivity of a-SiO thin films is insensitive to the temperature from -55 °C to 150 °C. Nevertheless, in the range of the thickness in this work, the thermal conductivity of the crystalline SiO (c-SiO) thin films conforms to the T with the exponent range from -0.12 to -0.37, and the thinner films are less sensitive to temperature. Meanwhile, the thermal conductivity of a-SiO with thickness beyond 4.26 nm has no significant size effect, which is consistent with the experimental results. Compared with c-SiO thin film, the thermal conductivity of a-SiO is less sensitive to defects. Particularly, the effect of spherical void defects on the thermal conductivity of a-SiO is followed by Coherent Potential model, which is helpful for the design of low-K material based porous a-SiO thin film in microelectronics.
非晶态SiO(a-SiO)薄膜因其优异的热稳定性和绝缘性能而被广泛应用于集成电路(IC)中。本文采用非平衡分子动力学(NEMD)模拟系统地研究了a-SiO薄膜的热导率。除了a-SiO薄膜热导率的尺寸效应和温度效应外,还考察了缺陷诱导的热导率调谐效应。研究发现,a-SiO薄膜的热导率在-55°C至150°C的温度范围内对温度不敏感。然而,在本工作的厚度范围内,晶体SiO(c-SiO)薄膜的热导率符合指数范围为-0.12至-0.37的T关系,且较薄的薄膜对温度不太敏感。同时,厚度超过4.26nm的a-SiO的热导率没有明显的尺寸效应,这与实验结果一致。与c-SiO薄膜相比,a-SiO的热导率对缺陷不太敏感。特别是,球形空洞缺陷对a-SiO热导率的影响遵循相干势模型,这有助于微电子中基于低介电常数材料的多孔a-SiO薄膜的设计。