Acceptor Doped Barium Titanate Based Thin Film Capacitors on Metal Foils and Methods of Making Thereof

Abstract

The present invention is directed to a dielectric thin film composition comprising: (1) one or more barium/titanium-containing additives selected from (a) barium titanate, (b) any composition that can form barium titanate during firing, and (c) mixtures thereof; dissolved in (2) organic medium; wherein the barium/titanium-containing additives are not intentionally modified or doped; wherein the composition has been annealed in an environment having an oxygen partial pressure of less than about 10 −7 atmospheres and/or at a temperature in the range of 700° C. and 1050° C.; wherein a capacitor comprising the composition would have a loss tangent of greater than about 0.07; and wherein the composition is not reoxygenated.

1 . A dielectric thin film composition comprising: 
 (1) one or more barium/titanium-containing additives selected from the group consisting of (a) barium titanate, (b) any composition that can form barium titanate during firing, and (c) mixtures thereof; dissolved in    (2) organic medium;    wherein the barium/titanium-containing additives are not modified or intentionally doped;    wherein the composition has been annealed in an environment having an oxygen partial pressure of less than about 10 −7  atmospheres and/or at a temperature in the range of 700° C. and 1050° C.;    wherein a capacitor comprising the composition would have a loss tangent of greater than about 0.07; and    wherein the composition is not reoxygenated.    
   
   
       2 . The composition of  claim 1  wherein the barium in said barium/titanium-containing additive has been partially or substantially replaced by one or more metal cations having the oxide stoichiometry of MO wherein M is selected from the group consisting of (a) strontium; (b) lead; (c) calcium; and (d) mixtures thereof.  
   
   
       3 . The composition of  claim 1  wherein the titanium in said barium/titanium-containing additive has been partially or substantially replaced by one or more metal cations having the oxide stoichiometry of MO 2  wherein M is selected from the group consisting of (a) zirconium; (b) hafnium; (c) tin; and (d) mixtures thereof.  
   
   
       4 . A capacitor comprising the thin film composition of  claim 1  and having a loss tangent greater than about 0.07.  
   
   
       5 . An innerlayer panel comprising the capacitor of  claim 4 .  
   
   
       6 . A printed wiring board comprising the capacitor of  claim 4 .  
   
   
       7 . A method of making a capacitor comprising:  
     providing a metallic foil;  
     forming a dielectric over the metallic foil, 
 wherein forming the dielectric comprises:  
 forming a dielectric layer over the foil  
 wherein the dielectric layer is formed from the composition of  claim 1;   
 annealing the dielectric layer; and  
 forming a conductive layer over the dielectric,  
 whereby the metallic foil, the dielectric, and the conductive layer form the capacitor.  
 
   
   
       8 . The method of  claim 7 , wherein annealing comprises annealing at a temperature in the range of about 700° C. to 1050° C.  
   
   
       9 . The method of  claim 7 , wherein annealing comprises annealing in an environment having an oxygen partial pressure of less than about 10 −7  atmospheres.  
   
   
       10 . The method of  claim 7 , wherein annealing results in a dielectric comprising crystalline barium titanate or crystalline barium strontium titanate.  
   
   
       11 . The method of  claim 7 , wherein the capacitor has a capacitance density of at least 1.5 μF/cm 2 .  
   
   
       12 . A method of using a capacitor comprising the composition of  claim 1 , comprising: 
 embedding the capacitor into a printed wiring board.    
   
   
       13 . The method of  claim 12 , wherein the embedded capacitor is used to dampen fluctuations of voltage around a desired value.