Scaling Behaviors of Surface Roughening of Cu Thin Films Deposited by Oblique Angle Deposition

摘要

Cu thin films with different thicknesses were deposited by magnetron sputtering at various oblique angle 6 of incidence between the deposition flux and the substrate surface normal. Cross-section microstructure and surface morphology of the films were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM), respectively. Then the scaling behaviors of film surface roughening were analyzed in terms of dynamic scaling theory. With the increasing of the deposition angle 8, the angle δ between grain growth direction and substrate surface normal increased gradually. With increasing 8 in the range of <500, the roughness exponent a increased from 0.76 to 0.82 and the growth exponent β decreased from 0.42 to 0.35. However, when 8 increased to 70°, a and p changed to 0.72 to 0.61, respectively. The evolution of the scaling exponents effectively revealed the fact that the film surface roughening arises from the competition between surface diffusion and shadowing effect.