Dielectric properties of anodic films on sputter-deposited Ti-Si porous columnar films |
| |
Authors: | M Tauseef Tanvir T FujiiY Aoki K FushimiH Habazaki |
| |
Institution: | a Division of Materials Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan b Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad 45650, Pakistan |
| |
Abstract: | For electrolytic capacitor application of the single-phase Ti alloys containing supersaturated silicon, which form anodic oxide films with superior dielectric properties, porous Ti-7 at% Si columnar films, as well as Ti columnar films, have been prepared by oblique angle magnetron sputtering on to aluminum substrate with a concave cell structure to enhance the surface area and hence capacitance. The deposited films of both Ti and Ti-7 at% Si have isolated columnar morphology with each column revealing nanogranular texture. The distances between columns are ∼500 nm, corresponding to the cell size of the textured substrate and the gaps between columns are 100-200 nm. When the porous Ti-7 at% Si film is anodized at a constant current density in ammonium pentaborate electrolyte, the growth of a uniform amorphous oxide film continues to ∼35 V, while it is limited to less than 6 V on the porous Ti film. The maximum voltage of the growth of uniform amorphous oxide films on the Ti-7 at% Si films is similar for both the flat and porous columnar films, suggesting little influence of surface roughness on the amorphous-to-crystalline transition of growing anodic oxide under the high electric field. Due to the suppression of crystallization to sufficiently high voltages, the anodic oxide films formed on the porous Ti-7 at% Si film shows markedly improved dielectric properties, in comparison with those on the porous Ti film. |
| |
Keywords: | Porous deposits Non-equilibrium alloy Oblique angle deposition Anodic oxide Dielectric |
本文献已被 ScienceDirect 等数据库收录! |
|