Interfacial thermal transport characteristics and heat transfer enhancement mechanisms of Ga/AlN composite thermal interface materials

This study systematically investigates the interfacial thermal transport characteristics of gallium/aluminum nitride (Ga/AlN) composite thermal interface materials. The non-equilibrium molecular dynamics simulation and phonon analysis method are applied to reveal the regulatory mechanisms at the interface. Result shows that the temperature exhibits a non-monotonic regulatory effect on interfacial thermal resistance (ITR). Within the temperature range of 298 K to 1023 K, the ITR increases and then decreases with increasing temperature. Meanwhile, the interfacial atomic bonding properties play a decisive role in the thermal resistance. The ITR of the Ga/AlN-N interface is about 50 % lower than that of the Ga/AlN-Al interface, which is attributed to the Ga-N chemical bonding to enhance the thermal transport. Correspondingly, the phonon participation rate (PPR) analysis shows that the PPR at the Ga/AlN-N interface is significantly higher than that at the Ga/AlN-Al interface, indicating that the bonding weakens the phonon localization. In addition, the thermal cycling might lead to the accumulation of interfacial defects, and the ITR increases by about 40 % after 20 cycles. The heating direction might similarly affect the ITR, which can be reduced by 15–20 % with the center-heating mode reducing the in comparison to the boundary-heating mode.