Solid electrolytic capacitor containing a sequential vapor-deposited dielectric film
A capacitor comprising a solid electrolytic capacitor element that contains a sintered porous anode body, a dielectric film that is formed by sequential vapor deposition and overlies the anode body, and a solid electrolyte that overlies the dielectric film is provided. A method for forming a solid electrolytic capacitor element is also provided.
1. A method for forming a solid electrolytic capacitor element, the method comprising forming a dielectric film on a porous sintered anode body by a sequential vapor deposition process, the sequential vapor deposition process including subjecting the anode body to a reaction cycle that includes contacting the anode body with a gaseous precursor compound that bonds to a surface of the anode body and thereafter contacting the anode body with a gaseous oxidizing agent to oxidize the precursor compound, and thereafter forming a solid electrolyte by a process that includes applying a dispersion that includes a plurality of conductive polymer particles over the dielectric film.
2. The method of claim 1 , wherein the precursor compound is a tantalum-containing precursor compound.
3. The method of claim 2 , wherein the precursor compound is a tantalum halide.
4. The method of claim 2 , wherein the precursor compound is a tantalum alkoxide, alkylamido tantalum compound, or a combination thereof.
5. The method of claim 1 , wherein the porous anode body includes tantalum, niobium oxide, or a combination thereof.
6. The method of claim 1 , wherein the oxidizing agent has a boiling point of about 310° C. or less.
7. The method of claim 1 , wherein the oxidizing agent includes water, oxygen, ozone, a peroxide, an alcohol, a halide, or a combination thereof.
8. The method of claim 1 , wherein the anode body is heated to a temperature of about 400° C. or less during the reaction cycle.
9. The method of claim 1 , further comprising contacting the anode body with an inert gas prior to contact with the oxidizing agent.
10. The method of claim 1 , further comprising subjecting the anode body to one or more additional reaction cycles that include contacting the anode body with a gaseous precursor compound and thereafter contacting the anode body with a gaseous oxidizing agent.
11. The capacitor of claim 1 , wherein the conductive polymer particles contain poly(3,4-ethylenedioxythiophene) or a derivative thereof.
12. The capacitor of claim 1 , wherein the conductive polymer particles also contain a polymeric counterion.
13. The capacitor of claim 1 , wherein the conductive polymer particles have an average diameter of from about 1 nanometer to about 80 nanometers.
14. The capacitor of claim 1 , wherein the conductive polymer particles constitute from about 0.1 wt. % to about 10 wt. % of the dispersion.
15. The capacitor of claim 1 , wherein the solid electrolyte has a total thickness of from about 1 micrometer to about 200 micrometers.