The Effect of Pore Defects on the Interfacial Thermal Resistance of GaN-Diamond Heterostructure

Heat transfer across the GaN-diamond interface is very important in the thermal management of GaN electronics on diamond substrates. The influence of various defects caused by manufacturing processes on the thermal resistance of the GaN-diamond interface is still unclear. In this work, we use non-equilibrium molecular dynamics simulations to investigate the effect of possible pore defects on GaN-diamond interfacial heat transport. Square pores of different sizes are introduced at the GaN-diamond interface. By changing the pore cross-sectional area, we found that the introduction of pore defects will significantly increase the interfacial thermal resistance compared with the case without defects. Pores can also cause more significant stress and strain on the edge atoms at the interface and may hinder the normal transmission of phonons. At the same time, we calculated the phonon density of states (PDOS) corresponding to different pore sizes to analyze the reason for the change in interfacial thermal resistance. PDOS calculation results show that the higher porosity leads to the enhancement of phonon scattering at the interface. The low-frequency phonons that are more easily transmitted through the interface are scattered into high-frequency phonons, increasing the thermal resistance of the interface.