Methods of making thin film capacitors comprising a manganese doped barium titantate dielectric
View Patent ↗Described herein are methods for making articles comprising a dielectric layer formed from any solution composition that can form barium titanate during firing and containing manganese in an amount between 0.002 and 0.05 atom percent of the solution composition, wherein the dielectric layer has been formed on metal foil and fired in a reducing atmosphere.
1. A method of making a capacitor comprising:
providing a metallic foil;
forming a dielectric layer over the metallic foil,
wherein the dielectric layer is formed from a solution composition that forms barium titanate during annealing and
contains manganese in an amount between 0.002 and 0.05 atom percent of the solution composition;
annealing the dielectric layer at a temperature between about 800° C. to 1050° C. and in a reducing atmosphere having an oxygen partial pressure of less than about 10 −8 atmospheres to form a dielectric having a thickness between 0.4 and 1.0 micrometer; and
forming a conductive layer over the dielectric, wherein the metallic foil, the dielectric, and the conductive layer form the capacitor, and wherein the dielectric is not re-oxygenated after annealing and wherein the capacitor has a leakage current density of less than approximately 1 milli-amp/cm 2 at 10 volts.
2. The method of claim 1 , wherein annealing results in a dielectric comprising crystalline barium titanate or crystalline barium strontium titanate.
3. The method of claim 1 , wherein the capacitor has a capacitance density of at least 0.5 μF/cm 2 .
4. The method of claim 1 , wherein the capacitor has breakdown voltage greater than 20 volts.
5. The method of claim 1 , wherein the capacitor has a dissipation factor less than about 8%.
6. The method of claim 1 , wherein the dielectric layer is formed from a solution composition comprising barium acetate.
7. The method of claim 1 , wherein the dielectric layer is formed from a solution composition comprising titanium isopropoxide.
8. The method of claim 7 , wherein the titanium of said titanium isopropropoxide is partially or substantially replaced by zirconium, hafnium, tin or mixtures thereof.
9. The method of claim 1 , wherein the dielectric layer is formed from a solution composition comprising titanium butoxide.
10. The method of claim 1 , wherein the dielectric layer is formed from a solution composition comprising manganese acetate tetrahydrate.
11. The method of claim 1 wherein in the forming of the conductive layer over the dielectric, the conductive layer is formed by a process selected from sputtering, combustion vapor deposition, electroless plating, and printing.