Polishing-induced material attrition in surface-texturing AlN using a nanoscale polishing tool: An atomic-scale understanding

This study examines the alterations in the material properties and the effectiveness of the nano-polishing process applied to the surface of AlN substrate material through molecular dynamics simulations. Various controlled parameters at the outset of the polishing process, including polishing depth, polishing speed, and surface texture, exert both positive and negative influences on substrate characteristics, such as polishing force, friction coefficient, atomic phase transformation, subsurface damage layer (SDL), von Mises stress, temperature, dislocation characteristics, surface topography, atom removal, and root-mean-square (RMS). The results depicted that great polishing depth and slow polishing velocity have adverse effects on the internal structure of the material, leading to the creation of a substantial SDL and a dense network of dislocation formation. Conversely, increased material polishing velocity results in elevated von Mises stress and high generated temperatures. When combined with the initial surface structure conditions of the material, this mitigates detrimental effects on the internal structural characteristics while facilitating the phase transformation process and enhancing atom removal efficiency. The calculated RMS results of the substrate demonstrate that adjustments in polishing speed yield a higher improvement in surface roughness compared to alterations in polishing depth and surface texture. Therefore, a comprehensive understanding of the impact of initial conditions in the polishing process, as well as the atomiclevel surface structure of the substrate, aids in selecting the most appropriate polishing conditions to produce the highest-quality products.