Modification of various properties of HfO₂ thin films obtained by changing magnetron sputtering conditions

In this work properties of hafnium dioxide (HfO₂) thin films deposited by magnetron sputtering with different powers (i.e. 200 W, 400 W and 600 W) were described. Based on microstructure measurements obtained by X-ray diffraction, Raman scattering and transmission electron microscopy method it was observed that there is a significant influence of the sputtering power on investigated properties of HfO₂ thin films. Increase of the sputtering power caused, e.g. an increase of average crystallite size and surface roughness. Microstructure of thin films deposited with lower power was composed from a large number of voids that resulted in significant changes of their optical and mechanical properties. Results of optical studies showed that all deposited thin films were well transparent in a visible light range. Refractive index increased gradually with an increase of deposition power from 1.86 (200 W) to 2.09 (600 W). Performed investigations of mechanical properties revealed that hardness and Young’s elastic modulus of HfO₂ thin films increased with an increase of the sputtering power.