Bulk capacitor and method
View Patent ↗A bulk capacitor includes a first electrode formed of a metal foil and a semi-conductive porous ceramic body formed on the metal foil. A dielectric layer is formed on the porous ceramic body for example by oxidation. A conductive medium is deposited on the porous ceramic body filling the pores of the porous ceramic body and forming a second electrode. The capacitor can then be encapsulated with various layers and can include conventional electrical terminations. A method of manufacturing a bulk capacitor includes forming a conductive porous ceramic body on a first electrode formed of a metal foil, oxidizing to form a dielectric layer and filling the porous body with a conductive medium to form a second electrode. A thin semi-conductive ceramic layer can also be disposed between the metal foil and the porous ceramic body.
1. A bulk capacitor, comprising:
a first electrode formed of a metal foil,
a semi-conductive porous ceramic body deposited on the metal foil,
a dielectric layer formed on the porous ceramic body,
a semi-conductor ceramic layer disposed between the metal foil and the porous ceramic body, and
a conductive medium filling at least a portion of porous ceramic body forming a second electrode.
2. The bulk capacitor of claim 1 further comprising a conductive metal layer encapsulating the porous ceramic body.
3. The bulk capacitor of claim 2 wherein the conductive metal layer comprises silver.
4. The bulk capacitor of claim 1 wherein the metal foil has a geometric profile.
5. The bulk capacitor of claim 1 wherein the conductive medium comprises a conductive polymer.
6. The bulk capacitor of claim 1 wherein the dielectric layer is formed on a free surface of the porous ceramic body.
7. The bulk capacitor of claim 1 wherein the dielectric layer is formed on porous ceramic body and on the metal foil.
8. A bulk capacitor, comprising:
a first electrode formed of a metal foil,
a semi-conductive porous ceramic body deposited on the metal foil, a dielectric layer formed on the porous ceramic body,
a conductive medium filling at least a portion of porous ceramic body forming a second electrode, and
a first electrical lead coupled to the first electrode and a second electrical lead coupled to the second electrode, wherein the first electrical lead and second electrical lead are configured to mate with first and second conductive pads located on a mounting substrate.
9. The bulk capacitor of claim 8 wherein the first and second electrode are joined to the first and second conductive pads via a conductive adhesive.
10. The bulk capacitor of claim 9 further comprising a non-conductive adhesive disposed between the first and second electrical leads.
11. A method of manufacturing a bulk capacitor, the method comprising:
forming a conductive porous ceramic body on a first electrode comprising a metal foil,
oxidizing the porous ceramic body to form a dielectric layer,
forming a semi-conductive ceramic layer between the metal foil and the porous ceramic body, and
filling the porous ceramic body with a conductive medium forming a second electrode.
12. The method of claim 11 comprising encapsulating the porous ceramic body with a conductive metal layer.
13. The method of claim 12 wherein the conductive metal layer comprises silver.
14. The method of claim 11 comprising forming a geometric profile in the metal foil.
15. The method of claim 11 wherein the oxidizing is performed thermally.
16. The method of claim 11 wherein the oxidizing is performed electrochemically.
17. The method of claim 11 wherein the conductive medium comprises a conductive polymer.
18. The method of claim 11 wherein the dielectric layer is formed on porous ceramic body and on the metal foil.
19. A method of manufacturing a bulk capacitor, the method comprising:
forming a conductive porous ceramic body on a first electrode comprising a metal foil,
oxidizing the porous ceramic body to form a dielectric layer, and
filling the porous ceramic body with a conductive medium forming a second electrode,
wherein a first electrical lead is coupled to the first electrode and a second electrical lead is coupled to the second electrode, wherein the first electrical lead and second electrical lead are configured to mate with first and second conductive pads located on a mounting substrate.
20. The method of claim 19 wherein the first and second electrode are joined to the first and second conductive pads via a conductive adhesive.
21. The method of claim 20 wherein a non-conductive adhesive is disposed between the first and second electrical leads.