The structural properties of thin films prepared with different thicknesses before and after the annealing process and at different temperatures were studied. X-ray diffraction (XRD), atomic force microscopy (AFM), and emission scanning electron microscopy (FESEM) were used to study the structural properties. X-ray diffraction analysis revealed that the thin films prepared with different thicknesses, as well as those annealed at temperatures of 300 and 373 K, were composed of the β-phase, which is widely known as the most stable phase. The analysis also showed that the material has a polycrystalline structure characterized by a monoclinic crystal system. The density shows a constant increase in all thin films, with the dominant trend being (312) for all films. Atomic force microscopy (AFM) measurement results indicated that there was an increase in roughness with a change in the thickness of the thin films. In addition, there was an increase in the crystalline size of the thin films that underwent annealing at 300 and 373 K. However, there was a decrease in crystallite size at the annealing temperature of 473 K due to the phase change of the thin film material.