Thermal transport mechanism of AlN/SiG/3C–SiC typical heterostructures

Understanding the heat transfer mechanism of typical structures in high-power chips is essential for chip design with better engineered heat transfer performance. Here, the interfacial thermal resistance (ITR) and in-plane thermal conductivity (TC) of AlN/Si-doped graphene/3C–SiC (AlN/SiG/3C–SiC) heterostructures are systematically studied by molecular dynamics simulation. Silicon doping can reduce the ITR by as much as 31.72% with a concentration of 8%, which is verified furthermore by energy transport and thermal relaxation time. Multiple analyses indicate that Si doping results in the enhancement of strong interaction between 3C–SiC and SiG, the decline of weak interaction between AlN and other two materials due to the accumulation of wrinkles in SiG, and finally promotes the phonon transmission of 0–18 THz at interfaces owing to the dominance of strong interaction. In addition, the in-plane TC is reduced by 11.24% when the Si-doped concentration is 8%. By analyzing the stress field, SiG and two-layer atoms on the interface side of 3C–SiC are mainly responsible for thermal resistance, and SiG leads to the exponential dependence between TC and doping concentration. The results also show that the ITR is sensitive to the random doping positions, while the TC is not. We believe the results in this work will have important guiding significance for enhancing the thermal transport performance of high-power chips.