Solid electrolytic capacitor containing a sequential vapor-deposited dielectric film
A capacitor which can be reliably employed at high voltages is provided. More particularly, the capacitor comprises 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.
1. A capacitor comprising a solid electrolytic capacitor element that contains a sintered porous anode body containing niobium or an oxide of niobium, a homogeneous dielectric film that consists essentially of an oxide of tantalum that is formed by sequential vapor deposition and overlies the anode body, wherein the dielectric film has a uniform thickness of from about 10 nanometers to about 1,000 nanometers, and a solid electrolyte that overlies the dielectric film.
2. The capacitor of claim 1 , wherein the dielectric film is formed by atomic layer deposition, molecular layer deposition, or a combination thereof.
3. The capacitor of claim 1 , wherein the dielectric film includes tantalum pentoxide.
4. The capacitor of claim 3 , wherein the vapor-deposited dielectric film is formed from a tantalum-containing precursor compound.
5. The capacitor of claim 4 , wherein the precursor compound is a tantalum halide.
6. The capacitor of claim 4 , wherein the precursor compound is a tantalum alkoxide, alkylamido tantalum compound, or a combination thereof.
7. The capacitor of claim 1 , wherein the sintered porous anode body includes tantalum, niobium oxide, or a combination thereof.
8. The capacitor of claim 1 , wherein the solid electrolyte includes manganese dioxide.
9. The capacitor of claim 1 , wherein the solid electrolyte includes a conductive polymer.
10. The capacitor of claim 9 , wherein the solid electrolyte contains a plurality of conductive polymer particles.
11. The capacitor of claim 10 , wherein the conductive polymer particles contain poly(3,4-ethylenedioxythiophene) or a derivative thereof.
12. The capacitor of claim 10 , wherein the conductive polymer particles also contain a polymeric counterion.
13. The capacitor of claim 9 , wherein the conductive polymer is an extrinsically conductive polymer.
14. The capacitor of claim 13 , wherein the extrinsically conductive polymer has repeating units of the following formula (I):
wherein,
R 7 is a linear or branched, C 1 to C 18 alkyl radical, C 5 to C 12 cycloalkyl radical, C 6 to C 14 aryl radical, C 7 to C 18 aralkyl radical, or a combination thereof; and
q is an integer from 0 to 8.
15. The capacitor of claim 9 , wherein the conductive polymer is an intrinsically conductive polymer.
16. The capacitor of claim 15 , wherein the intrinsically conductive polymer has repeating units of the following formula (II):
wherein,
R is (CH 2 ) a —O—(CH 2 ) b -L, where L is a bond or HC([CH 2 ] c H);
a is an integer from 0 to 10;
b is an integer from 1 to 18;
c is an integer from 0 to 10;
Z is an anion; and
X is a cation.
17. The capacitor of claim 1 , wherein the capacitor element further comprises a cathode coating that contains a metal particle layer that overlies the solid electrolyte, wherein the metal particle layer includes a plurality of conductive metal particles dispersed within a resinous polymer matrix.
18. The capacitor of claim 1 , further comprising an anode termination that is in electrical connection with the sintered porous anode body, a cathode termination that is in electrical connection with the solid electrolyte, and a housing that encapsulates the capacitor element and leaves exposed a mounting surface of the anode termination and the cathode termination.
19. The capacitor of claim 1 , wherein the entire dielectric film is formed by sequential vapor deposition.
20. The capacitor of claim 1 , wherein only a portion of the dielectric film is formed by sequential vapor deposition.
21. The capacitor of claim 1 , wherein the sintered porous anode body contains niobium (II) oxide.