Method for producing capacitor, capacitor, wiring board, electronic device, and ic card

Abstract

There is provided a method for producing a capacitor which is capable of producing a capacitor having a high withstand voltage and low leakage current, the method for producing a capacitor which is a method for producing a capacitor having a substrate serving as one electrode, a dielectric layer formed on top of the substrate, and the other electrode formed on top of the dielectric layer, the method including a step for forming an amorphous titanium oxide layer which is to become the dielectric layer on top of the substrate by anodizing the substrate, which is composed of titanium or titanium alloy, in an electrolyte solution containing hydrogen peroxide and having a temperature of 3° C. or less; and a step for forming the other electrode on top of the dielectric layer.

1 .- 8 . (canceled) 
     
     
         9 . A capacitor produced using a method for producing a capacitor having a substrate serving as one electrode, a dielectric layer formed on top of the substrate, and the other electrode formed on top of the dielectric layer,
 the method comprising:   a step for forming an amorphous titanium oxide layer which is to become the dielectric layer on top of the substrate by anodizing the substrate, which is composed of titanium or titanium alloy, in an electrolyte solution containing hydrogen peroxide and having a temperature of 3° C. or less; and   a step for forming the other electrode on top of the dielectric layer.   
     
     
         10 . A capacitor having a substrate serving as one electrode, a dielectric layer formed on top of the substrate, and the other electrode formed on top of the dielectric layer,
 the capacitor comprising the substrate composed of titanium or titanium alloy; and   the dielectric layer including an amorphous titanium oxide layer.   
     
     
         11 . The capacitor according to  claim 10 , wherein the dielectric layer is a laminated body including the amorphous titanium oxide layer and an insulating material layer. 
     
     
         12 . The capacitor according to  claim 9 ,
 wherein a refractive index of the amorphous titanium oxide layer at a wavelength of 632.8 nm is within a range from 1.90 to 2.35.   
     
     
         13 . The capacitor according to  claim 9 , wherein a relative dielectric constant of the amorphous titanium oxide layer is within a range from 30 to 50. 
     
     
         14 . The capacitor according to  claim 9 ,
 wherein the product of capacitance density and dielectric breakdown voltage at a measuring frequency of 1 kHz is 200 nF·V/cm 2  or more.   
     
     
         15 . The capacitor according to  claim 9 , wherein a dielectric loss tangent at a measuring frequency of 1 kHz is 0.01 or less. 
     
     
         16 . The capacitor according to  claim 9 ,
 wherein an electrostatic capacitance at a measuring frequency of 1 MHz is 80% or more of an electrostatic capacitance at a measuring frequency of 100 Hz.   
     
     
         17 . A wiring board comprising the capacitor described in  claim 9 . 
     
     
         18 . An electronic device comprising the capacitor described in  claim 9 . 
     
     
         19 . An IC card comprising the capacitor described in  claim 9 . 
     
     
         20 . The capacitor according to  claim 10 ,
 wherein a refractive index of the amorphous titanium oxide layer at a wavelength of 632.8 nm is within a range from 1.90 to 2.35.   
     
     
         21 . The capacitor according to  claim 10 , wherein a relative dielectric constant of the amorphous titanium oxide layer is within a range from 30 to 50. 
     
     
         22 . The capacitor according to  claim 10 ,
 wherein the product of capacitance density and dielectric breakdown voltage at a measuring frequency of 1 kHz is 200 nF·V/cm 2  or more.   
     
     
         23 . The capacitor according to  claim 10 , wherein a dielectric loss tangent at a measuring frequency of 1 kHz is 0.01 or less. 
     
     
         24 . The capacitor according to  claim 10 ,
 wherein an electrostatic capacitance at a measuring frequency of 1 MHz is 80% or more of an electrostatic capacitance at a measuring frequency of 100 Hz.   
     
     
         25 . A wiring board comprising the capacitor described in  claim 10 . 
     
     
         26 . An electronic device comprising the capacitor described in  claim 10 . 
     
     
         27 . An IC card comprising the capacitor described in  claim 10 .