Co-sputtering deposition of HfO2 thin films: Insights into Cu and Ag doping effects

Abstract

This study comprehensively examines the structural, electrical, and electrochemical properties of Cu- and Ag-doped HfO₂ thin films deposited via the co-sputtering method. The dopant concentrations were precisely controlled by varying the DC magnetron sputtering power, allowing a systematic evaluation of their impact on film characteristics. Structural analysis revealed that the monoclinic phase of HfO₂ was retained, with minor crystallographic changes attributable to the dopants. Also, confirmed the successful incorporation of dopant ions, revealing variations in spin-orbital splitting values due to differences in ionic radii and electronic configurations. Morphological studies demonstrated that Ag doping reduced surface roughness and enhanced uniformity, whereas Cu doping increased roughness, resulting in a more irregular morphology.

TLM analysis highlighted improved conductivity in doped films, although the effect was limited by the oxidation states of dopants and the presence of oxygen vacancies. Electrochemical investigations through potentiodynamic polarization analysis revealed that Ag doping significantly improved corrosion resistance in alkaline environments, while Cu doping had the opposite effect, reducing corrosion resistance due to increased porosity and morphological irregularities. The results underscore the contrasting roles of Cu and Ag doping in modulating the functional properties of HfO₂ thin films, offering insights into their potential for applications in advanced electronic devices, resistive switching memory, and energy storage systems.