Recently, it was shown that smooth relatively thick films can be prepared from low melting point materials by ion bombardment in unbalanced magnetron sputtering. The transition from Zn films with rough surfaces and milky appearances to shiny ones with a smooth surface with increasing substrate bias is studied here from the point of view of X-ray diffraction (XRD) microstructural parameters, such as preferred grain orientation and lattice strain. Extremely strong (001) texture was found for the smooth films. A maximum of preferred orientation at the substrate biases of about 400 V corresponds to the maximum of argon content and also to the high XRD line broadening and low value of the lattice parameter c perpendicular to the surface.