Influence of Sputtering DC Sputtering Power on the Surface Evolution of Ti Thin Films: A Fractal Description

The power supplied to the target during a sputtering process affects surface evolution. As such, the influence of sputtering power on the growth of titanium (Ti) thin films was studied. The Ti thin films were deposited using a direct current (DC) magnetron sputtering system from a pure Ti target on a glass substrate at varying sputtering powers of 15% (54.12 W), 30% (109.70 W), and 50% (188.17 W) of the maximum system capacity. The thin films were then characterised for topography using atomic force microscopy (AFM), morphology using a field emission scanning electron microscope (FESEM), and crystallinity using an x-ray diffractometer (XRD). Furthermore, fractal analysis based on the AFM imaging was undertaken to evaluate the growth mechanisms of the Ti thin films. The thickness, grain size, and roughness of the thin films increased with the deposition power. The samples were mostly amorphous, although at 30% and 50%, a weak peak of Ti (002) was observed via x-ray diffraction. The fractal dimension (Df) decreased with increasing power. The multifractality strength increased with increasing power. Based on the fractal study, Volmer-Weber and Stranski-Krastanov's modes describe the growth mechanism of Ti thin films deposited at varying sputtering power.