Thermal conductivity of amorphous SiO2 thin film: A molecular dynamics study

Amorphous SiO2 (a-SiO2) 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-SiO2 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-SiO2 thin films, the effect of defects induced thermal conductivity tuning was also examined. It was found that the thermal conductivity of a-SiO2 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 SiO2 (c-SiO2) thin films conforms to the T−α 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-SiO2 with thickness beyond 4.26 nm has no significant size effect, which is consistent with the experimental results. Compared with c-SiO2 thin film, the thermal conductivity of a-SiO2 is less sensitive to defects. Particularly, the effect of spherical void defects on the thermal conductivity of a-SiO2 is followed by Coherent Potential model, which is helpful for the design of low-K material based porous a-SiO2 thin film in microelectronics.