Thin film capacitor and method of manufacturing thin film capacitor

Abstract

A thin film capacitor with high capacity and low leak current is provided. The thin film capacitor includes a nickel substrate with nickel (Ni) purity of 99.99 weight percent or above, and a dielectric layer and an electrode layer disposed in this order on the nickel substrate. The thin film capacitor is typically manufactured as follows. A precursor dielectric layer is formed on a nickel substrate with nickel purity of 99.99 weight percent or above, and is subjected to annealing to form a dielectric layer. The diffusion of impurities from the nickel substrate to the precursor dielectric layer during annealing is suppressed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional configuration diagram of a thin film capacitor according to an embodiment of the present invention;

FIG. 2 is a cross-sectional configuration diagram of the thin film capacitor according to a modification of the present invention;

FIG. 3 is a flow chart explaining a method of manufacturing the thin film capacitor; and

FIGS. 4A to 4B are cross-sectional configuration diagrams explaining a method of manufacturing the thin film capacitor.

FIG. 5 is a distribution in the thickness direction of impurities included in a dielectric layer of the thin film capacitor according to examples and comparative examples.

Claims

1. A thin film capacitor comprising; a nickel substrate with nickel (Ni) purity of 99.99 weight percent or above, anda dielectric layer and an electrode layer disposed in this order on the nickel substrate.

2. The thin film capacitor according to claim 1, wherein the nickel substrate includes at least one impurity selected from the group consisting of impurities of iron (Fe), titanium (Ti), copper (Cu), aluminum (Al), magnesium (Mg), manganese (Mn), silicon (Si), and chromium (Cr); and each of the contents of one or more impurities in the nickel substrate is 65 ppm or below.

3. The thin film capacitor according to claim 1, wherein the nickel substrate is a nickel plate with a thickness of 300 μm or above, or nickel foil with a thickness of 1 μm or above and below 300 μm.

4. The thin film capacitor according to claim 1, wherein the dielectric layer is formed of a dielectric material including at least one element selected from the group consisting of barium (Ba), strontium (Sr), calcium (Ca), lead (Pb), titanium (Ti), and zirconium (Zr).

5. The thin film capacitor according to claim 1, wherein the dielectric layer has a thickness of 0.05 μm or above and 5 μm or below.

6. The thin film capacitor according to claim 1, wherein at least one of the electrode layer and the nickel substrate has a plurality of electrode portions that are independent with each other.

7. A method of manufacturing a thin film capacitor comprising the steps of; forming a precursor dielectric layer on a nickel substrate with nickel purity of 99.99 weight percent or aboveforming a dielectric layer by crystallizing the precursor dielectric layer with annealing; andforming an electrode layer on the dielectric layer.

8. The method of manufacturing the thin film capacitor according to claim 7,

9. The method of manufacturing the thin film capacitor according to claim 7,