Spring stiffness and heterointerface effects on GaN/AlN double-layer composites polishing

Abstract

The actual polishing depth is one of the most crucial polishing factors, consistently less than its designed value. Through three-dimensional Molecular Dynamics (MD) simulations, this research examines how the polishing tool with various spring stiffness interacts with the GaN/AlN double-layer composite model to investigate the formation and impact of hetero-junction surface. A single polishing tool attached to a spring in the typical polishing orientation has allowed for considering various grain spring constants. It is found that the heterointerface evolves from a periodic 6-petaled flower shape to a hexagonal network post-relaxation, featuring coherent regions, stacking faults, and misfit dislocations, with stress concentration due to lattice mismatch. Besides, as the spring stiffness constant increases, the dislocation density distribution in the workpiece increases while that in the heterointerface decreases, leading to a significant decrease in bear tensile stress atoms at the heterointerface after the polishing process.