Niobium solid electrolytic capacitor and its production method

A technology of solid electrolysis and manufacturing method, applied in solid electrolytic capacitors, electrolytic capacitors, capacitors, etc., can solve the problems of easy generation of leakage current, reduction of electrostatic capacitance, etc., to reduce leakage current, improve capacitance retention, simple and efficient manufacturing Effect

Inactive Publication Date: 2008-10-22
SANYO ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, there are problems in that leakage current is easily generated in the dielectric layer, and the electrostatic capacity is reduced due to deviation from the cathode due to defects.

Method used

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  • Niobium solid electrolytic capacitor and its production method
  • Niobium solid electrolytic capacitor and its production method
  • Niobium solid electrolytic capacitor and its production method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] step 1:

[0048] First, a niobium powder having a CV value of 150,000 [μF·V / g] as a product of capacitance and electrolytic voltage of the niobium sintered body after the electrolytic oxide film was formed was mixed with niobium monoxide powder. The mixing ratio was such that the content of niobium monoxide powder was 20% by weight relative to the total mass of the anode.

[0049] Hereinafter, unless otherwise specified, the CV value in each of the Examples and Comparative Examples is 150,000 [µF·V / g]. Here, as the CV value in the present invention, a value measured in accordance with EIAJ RC-2361A of the Japan Electronic Machinery Industries Association standard is used. However, in this measurement, a 30% by weight sulfuric acid solution was used as the measurement liquid, the measurement frequency was 120 Hz, and the superimposition of the bias voltage was omitted.

[0050] Step 2:

[0051] The anode 1 composed of a porous sintered body is formed by sintering the ...

Embodiment 2

[0061] After the anodic oxidation using ammonium fluoride aqueous solution in step 2 of Example 1, anodic oxidation was performed again at 40° C. in 0.1% by weight phosphoric acid aqueous solution for two hours to form a dielectric layer. The composition of the formed dielectric layer was analyzed by XPS.

[0062] image 3 It is a graph showing the result of analyzing the composition of the dielectric layer by XPS.

[0063] image 3 In , the horizontal axis represents sputtering time (minutes), which corresponds to the thickness of the dielectric layer in the depth direction. The vertical axis on the left represents the abundance ratio (%) of Nb and O, and the vertical axis on the right represents the abundance ratio (%) of F and P.

[0064] Such as image 3 As shown, in this embodiment, P (phosphorus) exists near the surface of the dielectric layer. P is on the cathode side. When the depth of 10% of the maximum concentration of O is defined as the thickness of the diele...

Embodiment 3

[0087] A solid electrolytic capacitor A3 was produced in the same manner as in Example 1 except that the mixing ratio of the niobium monoxide powder in the mixture of niobium powder and niobium monoxide powder was 5% by weight.

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Abstract

Disclosed are a niobium solid electrolytic capacitor capable of reducing leak current that may occur in high heat treatment in a reflow process and capable of preserving the capacity before and after heat treatment, and a method for producing it. The niobium solid electrolytic capacitor comprises an anode containing an oxide of niobium monoxide or niobium dioxide and a metal of niobium or a niobium alloy, a dielectric layer formed on the surface of the anode, and a cathode formed on the dielectric layer, wherein the dielectric layer contains fluorine.

Description

technical field [0001] The invention relates to a niobium solid electrolytic capacitor and a manufacturing method thereof. Background technique [0002] Since niobium has a dielectric constant approximately 1.8 times larger than tantalum, which is a material of conventional solid electrolytic capacitors, it is attracting attention as a material for next-generation high-capacity solid electrolytic capacitors. [0003] However, when the solid electrolytic capacitor is mounted on the surface of the substrate, it may be exposed to high heat in a reflow process. In a niobium solid electrolytic capacitor, some of the oxygen in the dielectric layer made of niobium oxide diffuses to the anode, the thickness of the dielectric layer decreases, and defects may occur in the dielectric layer. As a result, a leakage current is likely to occur in the dielectric layer, and the electrostatic capacitance decreases due to separation from the cathode due to defects. [0004] As a method to pr...

Claims

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Application Information

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IPC IPC(8): H01G9/04H01G9/042H01G9/025H01G9/15
Inventor 小林泰三梅本卓史野野上宽
Owner SANYO ELECTRIC CO LTD
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