Multilayer capacitor comprising barium-titanate doped with silver and rare earth metal

• US 6,078,494 A
• Filed: 07/22/1998
• Issued: 06/20/2000
• Est. Priority Date: 08/28/1997
• Status: Expired due to Term

• Current Assignee: Dmc2 Electronic Materials B.V.
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Hansen, Peter
• Primary Examiner(s): Kincaid, Kristine
• Assistant Examiner(s): Dinkins, Anthony
• Application Number:
  US09/120,627
• Time in Patent Office: 699 Days
• Field of Search: 361/311, 361/312, 361/321.1, 361/321.2, 361/321.3, 361/321.4, 361/321.5, 501/134-139, 29/25.42
• US Class Current: 361/321.5
• CPC Class Codes: H01G 4/1227 based on alkaline earth titanates

Abstract

A capacitor including a ceramic dielectric of a dielectric ceramic composition including a doped barium-calcium-zirconium-titanate of the composition (Ba_1-α-μ-ν A.sub.μ D.sub.ν Ca.sub.α) [Ti_1-x-δ-μ'"'"'-ν'"'"' Mn.sub.δ A'"'"'.sub.μ'"'"' Zr_x ]_z O₃, where A=Ag, A'"'"'=Dy, Er, Ho, Y, Yb and Ga; D=Nd, Pr, Sm, Gd; D'"'"'=Nb, Mo, 0.10≦x≦0.25, 0≦μ≦0.01, 0≦μ'"'"'≦0.01, 0≦ν≦0.01, 0 ν'"'"'0.01, 0<δ≦0.01 and 0.995≦z<1 and 0≦α≦0.05, and including at least two electrodes, is characterized by a high dielectric constant K and a long service life, a low loss factor, a high insulation resistance and a capacitance with a low voltage dependence. The temperature dependence of its dielectric constant K corresponds to the EIA-standard Y5V.

Claims

1. A capacitor comprising a ceramic dielectric of a dielectric ceramic composition, which includes a doped barium-calcium-zirconium-titanate of the composition

(Ba_1-α

-μ

-ν

A.sub.μ

D.sub.ν

Ca.sub.α

)[Ti_1-x-δ

-μ

'"'"'-ν

'"'"' Mn.sub.δ

A'"'"'.sub.μ

'"'"' D'"'"'.sub.ν

'"'"' Zr_x ]_z O₃,

where

A=Ag,

A'"'"'is a member selected from the group consisting of Dy, Er, Ho, Y, Yb and Ga;

D is a member selected from the group consisting of Nd, Pr, Sm, Gd;

D'"'"' is a member selected from the group consisting of Nb or Mo

0.10≦

x ≦

0.25,

0≦

μ

≦

0.01,

0≦

μ

'"'"'≦

0.01,

0≦

ν

≦

0.01,

0≦

ν

'"'"'≦

0.01,

0<

δ

≦

0.01 and

0.995 ≦

z≦

1 and 0≦

δ

α

0.005, and comprising at least two electrodes.

2. A capacitor as claimed in claim 1, characterized in that the doped barium-calcium-zirconium-titanate has the composition

(Ba₀.96-ν

D.sub.ν

Ca₀.04) [Ti_1-x-δ

-μ

'"'"' Mn.sub.δ

A'"'"'.sub.μ

'"'"' Zr_x ]_z O₃, where

A is a member selected from the group consisting of Dy, Er, Ho, Y and Yb;

D is a member selected from the group consisting of Nd, Pr, Sm and Gd;

0.10≦

x ≦

0.25;

0≦

μ

'"'"'≦

0.01,

0≦

ν

≦

0.01,

0<

δ

≦

0.01 and

0.995≦

z≦

1.

3. A capacitor as claimed in claim 1, characterized in that the doped barium-calcium-zirconium-titanate has the composition

(Ba₀.96-μ

-ν

A₈₂ D.sub.ν

Ca₀.04)[Ti_1-x-δ

Mn.sub.δ

Zr_x ]_z O₃, where

A=Ag,

D is a member selected from the group consisting of Nb, Pr, Sm an Gd;

0.10≦

x≦

0.25;

0≦

μ

≦

0.01,

0≦

ν

≦

0.01,

0<

δ

≦

0.01 and

0.995≦

z≦

1.

4. A capacitor as claimed in claim 1, characterized in that the doped barium-calcium-zirconium-titanate has the composition (Ba₀.96-μ

A.sub.μ

Ca₀.04)[Ti_1-x-δ

-ν

'"'"' Mn.sub.δ

D'"'"'.sub.ν

'"'"' Zr_x ]_z O₃, where

A =Ag,

D'"'"'=Nb or Mo,

0.10≦

x≦

0.25;

0≦

μ

≦

0.01,

0≦

ν

'"'"'≦

0.01,

0<

δ

≦

0.01 and

0.995≦

z≦

1.

5. A capacitor as claimed in claim 1, characterized in that the doped barium-calcium-zirconium-titanate has the composition (Ba₀.09575 Nd₀.0025 Ca₀.04)[Ti₀.995-x Mn₀.0025 Y₀.0025 Zr_x]z O₃, where 0.18≦

x≦

0.22 and 0.995≦

z≦

0.999.

6. A capacitor as claimed in claim 1, characterized in that the material for the electrodes is nickel or a nickel alloy.

7. A capacitor as claimed in claim 1, characterized in that the capacitor is a multilayer capacitor comprising inner electrodes of nickel or a nickel alloy.

8. A capacitor as claimed in claim 1, characterized in that the dielectric ceramic composition comprises 0.1-1% by weight of a sintering aid.