关键词: 分子动力学, 键合, 界面扩散, 氮化镓, 金刚石

Abstract: To address the thermal management bottleneck of GaN power devices and the challenges posed by lattice and thermal mismatch in direct GaN/diamond integration, a molecular dynamics simulation model of the GaN/Ta–Au–Ta/diamond structure is constructed to investigate interfacial bonding and atomic diffusion behavior under different temperatures and pressures. Atomic motion characteristics are analyzed through mean square displacement, diffusion coefficient, and radial distribution function, while Atom Count Distribution along the z-axis is used to evaluate interfacial densification. The results indicate that increasing temperature from 298 K to 500 K and pressure from 0 MPa to 10 MPa significantly enhances interfacial diffusion, as evidenced by steeper MSD slopes, higher diffusion coefficients, and decreased RDF peak intensity, leading to intensified interfacial mixing. When the pressure increases to 15 MPa, atomic diffusion is suppressed. Ta atoms exhibit higher diffusion capability than Au atoms, facilitating faster interfacial densification, with the Au–Ta interface showing the highest degree of atomic disorder and pronounced intermixing. These findings reveal the atomic diffusion-assisted bonding mechanism mediated by the Ta–Au–Ta interlayer in GaN/diamond heterostructures and provides theoretical guidance for optimizing bonding parameters and improving thermal management performance in high-power electronic devices.

Key words: molecular dynamic, bonding, interfacial diffusion, GaN, diamond