Nano-scratch experiments of Au/NiCr multi-layered films for microwave integrated circuits

Au/NiCr multi-layered metallic films used in microwave integrated circuits were deposited on Al2O3 substrate by magnetron sputtering. The deformation behavior of films was investigated by nano-scratch measurement technique. It was found that deformation proceeds can be divided into three stages: at the low load regime, plastic deformation is dominant; then, the plastic/total deformation ratio decreases with the increase of load; finally, as the scratch load is increased to a critical value, film failure occurs. Experimental results indicate that plastic deformation always dominates over elastic deformation before the film failure. Most interesting is that as the load increases, the elastic and plastic curves come to intersect at the point where the elastic and plastic deformations have the same amount. It indicates that the film begins to delaminate and the critical load is determined.