Capacitors with high energy storage density and low esr

Abstract

Electrostatic capacitors with high capacitance density and high-energy storage are implemented over conventional electrolytic capacitor anode substrates using highly conformal contact layers deposited by atomic layer deposition. Capacitor films that are suitable for energy storage, electrical and electronics circuits, and for integration onto PC boards endure long lifetime and high-temperature operation range.

1 . A capacitor including a chemically etched metallic foil, said capacitor comprising:
 a conformal and substantially uniform dielectric layer grown over said metallic foil; and   a substantially uniform and conformal conductive film grown on said dielectric layer.   
     
     
         2 . The capacitor of  claim 1  wherein an additional metal foil is in substantial electrical contact with a portion of said conformal conductive film. 
     
     
         3 . The capacitor of  claim 1  wherein at least a portion of said conformal conductive film is grown by ALD. 
     
     
         4 . The capacitor of  claim 1 , further comprising an additional conductive layer in substantial electrical contact with said conformal conductive film. 
     
     
         5 . The capacitor of  claim 4  further comprising an additional metal foil in substantial electrical contact with a portion of said additional conductive film. 
     
     
         6 - 8 . (canceled) 
     
     
         9 . The capacitor of  claim 2  comprising:
 a capacitor core stack comprising:
 a first metal foil; and 
 a repeatable stack; 
 
 said repeatable stack comprises a selected number of foil pairs; and 
 said foil pairs comprise:
 said capacitor foil; and 
 said additional metal foil. 
 
 
     
     
         10 . The capacitor of  claim 5  comprising:
 a capacitor core stack comprising:
 a first metal foil; and 
 a repeatable stack; 
 
 said repeatable stack comprises a selected number of foil pairs; and 
 said foil pairs comprise:
 said capacitor foil; and 
 said additional metal foil. 
 
 
     
     
         11 . The capacitor of  claim 4  comprising:
 a capacitor core stack comprising a repeatable stack; and 
 said repeatable stack comprises a selected number of said capacitor foils. 
 
     
     
         12 . The capacitor of  claim 9  wherein electrical contacts formed on planar faces of said capacitor core stack, and said electrical contacts comprise:
 a first insulation over an edge of said additional metal foil on a first face; 
 a first electrical contact with the edge of said additional metal foil formed on the first face; 
 a second insulation over the edge of said additional metal foil on a second face; and 
 a second electrical contact with the edge of said additional metal foil formed on the second face. 
 
     
     
         13 - 14 . (canceled) 
     
     
         15 . The capacitor of  claim 9  wherein said capacitor core stack is cut into capacitor core pieces; and
 electrical contacts formed on two parallel sides of said capacitor core pieces; and 
 said electrical contacts comprise:
 a first insulation over an edge of said additional metal foil on the first side; 
 a first electrical contact with the edge of said metal foil formed on the first side; 
 a second insulation over the edge of said metal foil on a second side; and 
 a second electrical contact with the edge of said additional metal foil formed on the second side. 
 
 
     
     
         16 . The capacitor of  claim 10  wherein said capacitor core stack is cut into capacitor core pieces; and
 electrical contacts formed on two parallel sides of said capacitor core pieces; and 
 said electrical contacts comprise:
 a first insulation over an edge of said additional metal foil on a first side; 
 a first electrical contact with the edge of said metal foil formed on the first side; 
 a second insulation over the edge of said metal foil on a second side; and 
 a second electrical contact with the edge of said additional metal foil formed on the second side. 
 
 
     
     
         17 . The capacitor of  claim 11  wherein said capacitor core stack is cut into capacitor core pieces; and
 electrical contacts formed on two parallel sides of said capacitor core pieces; and 
 said electrical contacts comprise:
 a first insulation over an edge of said additional conductive layer on a first side; 
 a first electrical contact with the edge of said metal foil formed on the first side; 
 a second insulation over the edge of said metal foil on a second side; and 
 a second electrical contact with the edge of said additional conductive layer formed on the second side. 
 
 
     
     
         18 . The capacitor of  claim 1  wherein at least a portion of said dielectric layer is formed by ALD. 
     
     
         19 . The capacitor of  claim 1  wherein at least a portion of said dielectric layer is formed by anodic oxidation. 
     
     
         20 . The capacitor of  claim 18  wherein a portion of said dielectric layer is formed by anodic oxidation;
 a portion of said dielectric layer is formed by ALD; and 
 the thickness of said ALD portion is selected to substantially increase the breakdown voltage of said dielectric layer. 
 
     
     
         21 . The capacitor of  claim 1  wherein said capacitor foil is electrically biased; and
 said electrically biased comprises:
 applying electrical potential between said metal foil and said conformal conductive film; 
 said electrical potential is selected to increase the breakdown voltage of said dielectric layer; and 
 the capacitance of said capacitor is substantially maintained. 
 
 
     
     
         22 . The capacitor of  claim 1  wherein said capacitor foil is electrically biased; and
 said electrically biased comprises:
 applying electrical potential between said metal foil and said conformal conductive film; 
 said electrical potential is selected to reduce the leakage current through said dielectric layer; and 
 the capacitance of said capacitor is substantially maintained. 
 
 
     
     
         23 . The capacitor of  claim 1  wherein said dielectric layer is electrically biased; and
 said electrically biased comprises:
 applying electrical potential between said metal foil and an electrolyte; 
 said electrolyte provides electrical contact with said dielectric layer; 
 said electrical potential is selected to increase the breakdown voltage of said dielectric layer; and 
 the thickness of said dielectric layer is not substantially increased. 
 
 
     
     
         24 . The capacitor of  claim 1  wherein said capacitor foil is mounted onto a PCB; and
 said PCB comprises:
 electrical contact pads; 
 said mounting comprises substantially making low ESR electrical contact with said electrical contact pads; 
 said capacitor foil is delineated to define capacitors; 
 said defined capacitors comprise of selected capacitance; and 
 said selected capacitance is determined by the capacitance per area of said capacitor foil and the area of said defined capacitors. 
 
 
     
     
         25 . The capacitor of  claim 4  wherein said capacitor foil is mounted onto a PCB;
 said PCB comprises electrical contact pads; 
 said mounting comprises substantially making low ESR electrical contact with said electrical contact pads; 
 said capacitor foil is delineated to define capacitors; 
 said defined capacitors comprise of selected capacitance; and 
 said selected capacitance is determined by the capacitance per area of said capacitor foil and the area of said defined capacitors. 
 
     
     
         26 . The capacitor of  claim 1  wherein said metal foil comprises aluminum. 
     
     
         27 . The capacitor of  claim 1  wherein said dielectric layer comprises aluminum oxide. 
     
     
         28 . The capacitor of  claim 1  wherein said conformal conductive film comprises titanium nitride. 
     
     
         29 . The capacitor of  claim 1  wherein said high area comprises more than 10 times area enhancement. 
     
     
         30 . The capacitor of  claim 1  wherein said capacitor foil comprises:
 said high area on both sides; 
 said dielectric layer is grown on both sides of said metal foil; and 
 said conformal conductive film is grown on said dielectric layer on both sides of said capacitor foil. 
 
     
     
         31 . A capacitor fabrication method comprising providing a conductive foil having an irregular surface to augment its area and oxidizing the surface area of said conductive foil to form a dielectric film, said method comprising:
 conformally growing a conductive film onto said dielectric film to form a capacitor foil; and   completing said capacitor to include said capacitor foil.   
     
     
         32 . (canceled) 
     
     
         33 . The capacitor fabrication method as in  claim 31  comprising:
 stacking said capacitor foil into a capacitor core stack; 
 cutting said capacitor core stack into capacitor core pieces; 
 selecting two parallel sides on said capacitor core pieces; 
 electrically contacting the edge of said high area metal foil on said first side; and 
 electrically contacting the edge of said conductive film on said second side. 
 
     
     
         34 . A method of making a macroscopic capacitor comprising providing a substrate having a large surface area, said method comprising:
 forming a conformal layer of either a dielectric or a conductor over said substrate using atomic layer deposition; and   completing said macroscopic capacitor to include said conformal layer.   
     
     
         35 . A method as in  claim 34  wherein said forming comprises forming a dielectric material. 
     
     
         36 . A method as in  claim 34  wherein said dielectric material is selected from the group consisting of Al 2 O 3 , an oxide of silicon, Ta 2 O 5 , HfO 2 , ZrO 2 , TiO 2 , and combinations thereof. 
     
     
         37 . A method as in  claim 34  wherein said forming comprises forming a conductor. 
     
     
         38 . A method as in  claim 37  wherein said conductor is selected from the group consisting of Ti N, copper, tungsten, ruthenium, and combinations thereof. 
     
     
         39 . A method of  claim 34  wherein said completing comprises completing a discrete electrical component, a hybrid electrical component, or a portion of a printed circuit board.