Abstract
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.
Highlights
With the continuous miniaturization of integrated circuits (ICs), the characteristic dimension (CD) is shrinking into 10 nm and below[1,2,3,4]
The experimental results of Amorphous SiO2 (a-SiO2) thin films obtained by Kleiner et al.[26] and Lee et al.[12] (dashed line and black circles in Fig. 4(a)), show good consistency and exhibit the characteristic of lower than that of bulk silica, and the blue triangle is the thermal conductivity with thickness 20–1000 nm measured by and Kato et al.[27]
The effects of temperature, thickness and void defect on the thermal conductivity of SiO2 thin film are investigated by molecular dynamics method
Summary
With the continuous miniaturization of integrated circuits (ICs), the characteristic dimension (CD) is shrinking into 10 nm and below[1,2,3,4]. McGaughey et al studied the temperature dependence of thermal conductivity of amorphous SiO2 bulk material using equilibrium molecular dynamics (EMD) method[13,14]. Using non-equilibrium molecular dynamics (NEMD) method, Huang et al investigated the size effect of thermal conductivity in amorphous SiO2 thin films[15,16]. Coquil et al performed NEMD simulations to study the correlation between the thermal conductivity of amorphous SiO2 thin film and nanopore[17] Their results were consistent with those predicted by the CP (Coherent Potential) model when porosity was in the range of 10% to 35%. Compared with results in refs[18,19], our computed results reveal good consistency, which verify the rationality of the presented model and credibility of selected parameters in this simulation
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