Dielectric properties of anodic oxide films on tantalum

Kerrec, O.; Devilliers, Didier; Groult, Henri; Chemla, M.

doi:10.1016/0013-4686(94)00330-4

Cited by 108 publications

(70 citation statements)

References 11 publications

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“…The relative dielectric constant of Ta 2 O 5 film is reported to be dependent on the thickness but is 18.5 for thin anodic oxide films of less than 19 nm. 46 The experimentally observed value is in good agreement with this value, confirming the nanosized dots prepared in this study have dielectric properties similar to Ta 2 O 5 .…”

Section: Resultssupporting

confidence: 87%

“…45 It is quite interesting that the growth rate of the present nanosized Ta oxide dot pattern ͑ϳ1.23-1.69 nm/V͒ is comparable to the growth rate of the tantalum anodic oxide ͑ϳ1.7 nm/V͒. 46,47 Thus, it is reasonable to consider that the growth mechanism for the nanosized oxide is electrochemical anodic oxidation as schematically shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 63%

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Formation and electric property measurement of nanosized patterns of tantalum oxide by current sensing atomic force microscope

Kim¹,

Zhao²,

Uosaki³

2003

Journal of Applied Physics

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Nanosized patterns of tantalum oxide were fabricated on a tantalum substrate by applying a potential pulse utilizing current sensing atomic force microscopy ͑CSAFM͒. The dimensions of the dots were strongly dependent on the bias applied, scan rate, and potential pulse duration. By controlling these variables, the minimum size nanodots with full width at half maximum of 35 nm was achieved. Immediately after pattern formation, the electrical properties of the Ta oxide nanodots were measured using CSAFM. The charge transport at the CSAFM tip and the nanosized Ta oxide dot can be described by Poole-Frenkel type conduction. The relative dielectric constant of the nanosized Ta 2 O 5 dots was calculated to be 17. 8 -24.3, showing that the quality of the oxide was high. In addition, by controlling the substrate bias applied, pulse duration, and tip scan speed, nanosized Ta oxide lines with the desired dimensions were prepared.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 63%

Formation and electric property measurement of nanosized patterns of tantalum oxide by current sensing atomic force microscope

Kim¹,

Zhao²,

Uosaki³

2003

Journal of Applied Physics

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“…26) Surface roughness, inhomogeneous composition, and reaction rate variation depending on the plane orientation are the major contribution to CPE. [27][28][29] Fig. 4 shows imaginary part of admittance as a function of angular frequency, ω (= 2πf), in the frequency range of 1 Hz~1 kHz.…”

Section: Resultsmentioning

confidence: 99%

Preparation of Tantalum Anodic Oxide Film in Citric Acid Solution - Evidence and Effects of Citrate Anion Incorporation

Kim

Uosaki

2013

Journal of Electrochemical Science and Technology

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ABSTRACT:Tantalum anodic oxide film was prepared in citric acid solution of various concentrations and the prepared Ta anodic oxide film was characterized by various electrochemical techniques and X-ray photoelectron spectroscopy (XPS). The prepared Ta anodic oxide film showed typical n-type semiconducting properties and the dielectric properties were strongly dependent on the citric acid concentration. The variation of electrochemical and electronic properties was explained in terms of electrolyte anion incorporation into the anodic oxide film, which was supported by XPS measurements.

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“…where εr is the dielectric constant of the passive film (~60 [44] for TiO2 and ~25 [45] for Ta2O5), ε0 is the vacuum permittivity (8.854 × 10 −14 F•cm −1 ), q is the elementary charge (+e for electrons and −e for holes), Nq is the density of charge carriers (Nd for donors and Na for acceptors), E is the applied potential, Efb is the flat band potential, k is the Boltzmann constant (1.38 × 10 −23 J•K −1 ), and T is the absolute temperature (310 K). Figure 9 presents the Mott-Schottky plots for the passive films formed on the β-Ta coating, uncoated Ti-6Al-4V and commercially pure Ta potentiostatically polarized at 0.8 V for 1 h in Hank's …”

Section: Mott-schottky Analysismentioning

confidence: 99%

Nanocrystalline β-Ta Coating Enhances the Longevity and Bioactivity of Medical Titanium Alloys

Liu

Jiang

2016

Metals

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A β-Ta nanocrystalline coating was engineered onto a Ti-6Al-4V substrate using a double cathode glow discharge technique to improve the corrosion resistance and bioactivity of this biomedical alloy. The new coating has a thickness of~40 µm and exhibits a compact and homogeneous structure composed of equiaxed β-Ta grains with an average grain size of~22 nm, which is well adhered on the substrate. Nanoindentation and scratch tests indicated that the β-Ta coating exhibited high hardness combined with good resistance to contact damage. The electrochemical behavior of the new coating was systematically investigated in Hank's physiological solution at 37 • C. The results showed that the β-Ta coating exhibited a superior corrosion resistance as compared to uncoated Ti-6Al-4V and commercially pure tantalum, which was attributed to a stable passive film formed on the β-Ta coating. The in vitro bioactivity was studied by evaluating the apatite-forming capability of the coating after seven days of immersion in Hank's physiological solution. The β-Ta coating showed a higher apatite-forming ability than both uncoated Ti-6Al-4V and commercially pure Ta, suggesting that the β-Ta coating has the potential to enhance functionality and increase longevity of orthopaedic implants.

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Dielectric properties of anodic oxide films on tantalum

Cited by 108 publications

References 11 publications

Formation and electric property measurement of nanosized patterns of tantalum oxide by current sensing atomic force microscope

Formation and electric property measurement of nanosized patterns of tantalum oxide by current sensing atomic force microscope

Preparation of Tantalum Anodic Oxide Film in Citric Acid Solution - Evidence and Effects of Citrate Anion Incorporation

Nanocrystalline β-Ta Coating Enhances the Longevity and Bioactivity of Medical Titanium Alloys

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