Deposition of WO₃ Thin Films at Oblique Angle —Growth and Electrochemical Behavior

Abstract

WO₃ thin films were deposited by RF magnetron sputtering at different deposition angles and modifications in their morphological properties investigated, aiming applications as the cathode electrodes in lithium microbatteries. The surface properties of the produced samples such as roughness exponent, surface area, and grain size were analyzed by atomic force microscopy. The roughness exponents values that characterize the events through the morphology changes during the growth of the films were in the range of α = 0.67-0.77, for deposition angles between 0° and 82°. Two different diffusion events were observed in the deposition processes, a less atomic species diffusion at angles between 30° - 50° and high diffusion at both extremes of deposition angles of 0° or 82°. The samples obtained at less diffusion deposition processes exhibited a higher roughness. The electrochemical behavior of the studied WO₃ thin films revealed a strong dependence of their charge capacity on the deposition conditions with a clear correlation between the morphological properties of the films (grain size and roughness) and electrochemical performance. [DOI: 10.1380/ejssnt.2009.465]