MD simulation of hardness property of Al thin film sputtered on Si substrate and its related to Porosity

Abstract

In the present work, the relationship between structural and hardness properties of A1 thin film sputtered on Si substrate were investigated by a molecular dynamics (MD) method. Stress and packing ratio were investigated in the relation to porosity, both of which reflect sputtering conditions. Generally, higher compressive applied stress resulted in higher hardness. The influence of porosity on hardness was clarified using a model that had pores introduced randomly to the film. It was revealed that hardness of films increased with increasing packing ratio. Although stress in the film was affected by pore size, hardness was little influence by it. Simulated results well corresponded to the experimental observation that hardness increased with decreasing porosity. When a pore distribution existed in the thickness direction, it was suggested that pores decreased their influence on hardness with increasing distance from the surface.