Tantalum films with well-controlled roughness grown by oblique incidence deposition

We have investigated how tantalum films with well-controlled surface roughness can be grown by e-gun evaporation with oblique angle of incidence between the evaporation flux and the surface normal. Due to a more pronounced shadowing effect the root-mean-square roughness increases from about 2 to 33 nm as grazing incidence is approached. The exponent, characterizing the scaling of the root-mean-square roughness with length scale (a), varies from 0.75 to 0.93, and a clear correlation is found between the angle of incidence and root-mean-square roughness.