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Dielectric properties of anodic films on sputter-deposited Ti–Si porous columnar films
Title: | Dielectric properties of anodic films on sputter-deposited Ti–Si porous columnar films |
Authors: | Tanvir, M. Tauseef Browse this author | Fujii, T. Browse this author | Aoki, Y. Browse this author | Fushimi, K. Browse this author | Habazaki, H. Browse this author |
Keywords: | Porous deposits | Non-equilibrium alloy | Oblique angle deposition | Anodic oxide | Dielectric |
Issue Date: | 15-Jul-2011 |
Publisher: | Elsevier |
Journal Title: | Applied Surface Science |
Volume: | 257 |
Issue: | 19 |
Start Page: | 8295 |
End Page: | 8300 |
Publisher DOI: | 10.1016/j.apsusc.2011.01.036 |
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-tocrystalline 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. |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/47411 |
Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 幅崎 浩樹
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