Thin film capacitors on ceramic
View Patent ↗Thin-film capacitors are formed on ceramic substrates having high capacitance densities and other desirable electrical and physical properties. The capacitor dielectrics are annealed at high temperatures.
1. A method of making one or more thin-film capacitors on a substrate, comprising:
providing a ceramic substrate having a first conductive layer thereon;
forming a dielectric over the first conductive layer, wherein forming the dielectric comprises:
forming a dielectric layer over the first conductive layer; and
annealing at a temperature in the range of about 800° C. to 1050° C. and in an environment having an oxygen partial pressure of less than 10 −6 atmospheres; and
forming a second conductive layer over the dielectric, wherein the first conductive layer, the dielectric, and the second conductive layer form a capacitor.
2. The method of claim 1 , wherein providing the substrate comprises:
forming the first conductive layer over the substrate.
3. The method of claim 1 , wherein forming a dielectric over the first conductive layer comprises depositing precursor chemicals for forming thin film crystalline barium titanate and wherein annealing results in a dielectric comprising crystalline barium titanate.
4. The method of claim 3 wherein a chemical precursor solution for forming dielectric contains barium acetate and titanium isopropoxide.
5. The method of claim 1 , wherein the first conductive layer comprises at least one metal selected from the group consisting of: nickel, copper, manganese, molybdenum, and tungsten.
6. The method of claim 1 , wherein annealing comprises:
annealing in a nitrogen atmosphere.
7. The method of claim 1 , wherein forming the dielectric comprises:
providing a dielectric precursor solution; and
depositing the dielectric precursor solution over the first conductive layer.
8. The method of claim 1 , wherein forming the dielectric comprises:
re-oxygenating the dielectric resulting from the annealing.
9. The method of claim 8 , wherein re-oxygenating the dielectric comprises:
re-oxygenating the dielectric at a temperature in the range of 450-600° C. and an oxygen partial pressure in the range of 10 −2 to 10 −5 atmospheres.
10. The method of claim 1 , wherein forming the dielectric comprises:
forming a doped dielectric.
11. The method of claim 1 , wherein forming the dielectric comprises:
forming a dielectric having a thickness in the range of about 0.2-2.0 microns.
12. The method of claim 1 , wherein:
the first conductive layer comprises at least one metal selected from the group consisting of: platinum, palladium, gold and silver.
13. The method of claim 1 , wherein forming the second conductive layer comprises:
sputtering a conductive layer over the dielectric; and
plating the conductive layer with a conductive material.
14. The method of claim 1 , wherein providing the substrate comprises:
providing a substrate comprising at least one material selected from the group consisting of: magnesia, alumina, glass-ceramic, zirconia, magnesium aluminate, strontium titanate, and barium titanate.
15. The method of claim 1 , further comprising:
forming a plurality of electrodes from the second electrode layer, thereby forming a plurality of capacitors.
16. One or more capacitors made by the method of claim 1 mounted on a printed wiring board.
17. One or more capacitors made by the method of claim 1 mounted on an integrated circuit substrate.
18. An integrated circuit package comprising one or more capacitors made by the method of claim 1 .
19. An integrated passive device comprising one or more capacitors made by the method of claim 1 .
20. A method of making one or more thin-film capacitors on a substrate, comprising:
providing a ceramic substrate having a first conductive layer thereon;
forming a dielectric over the first conductive layer, wherein forming the dielectric comprises:
forming a dielectric layer over the first conductive layer;
annealing at a temperature of at least about 800° C.; and
re-oxygenating the dielectric resulting from the annealing at a temperature in the range of 450° C. to 600° C. and an oxygen partial pressure in the range of 10 −2 to 10 −5 atmospheres; and
forming a second conductive layer over the dielectric, wherein the first conductive layer, the dielectric, and the second conductive layer form a capacitor.