Study on deformation behaviors of nanopillar textured AlN in nanoindentation using molecular dynamics

Although nanoscale textured surfaces are widely used in mechanical components to improve mechanical properties, how the texture-parameters such as the shape and density of the surface textures affect the contact deformation behaviors of AlN remains elusive. Therefore, the design of surface textures of AlN micro/nanoelectromechanical systems (MEMS/NEMS) is still challenging. To study the influence of surface textures on deformation behaviors of AlN at nanoscale, in this work we study the nanoindentation process of AlN textured surface using molecular dynamics simulations. The force and deformation behaviors in the nanoindentation process of AlN textured surface are thoroughly investigated. We find that the pop-in event in the indentation of AlN textured surface is mainly due to the phase transformation and amorphization of AlN, specifically caused by the nucleation of amorphous structure and the formation of the sixfold-coordinated B1-AlN. And the plastic deformation behaviors of textured AlN are associated with the phase transformation, amorphization and dislocation motion. It is also found that due to the existence of grooves in the textured surface, the vacant part can absorb some wear atoms. Therefore, the texture pattern has a beneficial effect on reducing the influence of surface deformation. The results demonstrate that the geometric parameters of the textures have great effect on the indentation load and deformation behaviors of AlN materials. The insights gained in this work can guide the design of AlN MEMS/NEMS with surface textures.