Dielectric composition

• US 5,086,021 A
• Filed: 06/28/1990
• Issued: 02/04/1992
• Est. Priority Date: 06/28/1990
• Status: Expired due to Term

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Sasaki, Kyoichi, Swanson, Donald K.
• Primary Examiner(s): Dixon, Jr., William R.
• Assistant Examiner(s): MARCANTONI, PAUL D
• Application Number:
  US07/545,249
• Time in Patent Office: 586 Days
• Field of Search: 501/136, 501/137, 501/138, 252/62.64, 252/62.62, 252/62.3 V, 252/62.3 BT, 252/520, 252/521
• US Class Current: 501/137
• CPC Class Codes: C04B 35/465 based on alkaline earth metal titanates
• CPC Class Codes: C04B 35/468 based on barium titanates
• CPC Class Codes: H01G 4/12 Ceramic dielectrics H01G4/085 takes precedence

Abstract

A dielectric ceramic powder composition for forming multilayer ceramic devices having thin dielectric layers with low porosity and having a dissipation factor which meets or exceeds X7R specifications, and consisting essentially of an admixture of a major component ceramic powder particle and minor component additives the amounts of which are controlled within certain predetermined ratios.

Claims

1. A composition for forming a multilayer ceramic device having a thin dielectric layer with lower porosity and having a dissipation factor of 2.5% of less, an insulation resistance of 1000 ohm-Farads or more at 25°

C. and 100 ohm-Farads or more at 125°

C. and a temperature coefficient of capacitance of ±

15% deviation or less within a temperature range of -55°

C. to +125°

C. and consisting essentially of an admixture of;

(a) 97 to 99 wt % of a major component ceramic powder particle; and

(b) 1 to 3 wt % of minor component additives selected from the group consisting essentially of the oxides of cerium, neodymium, samarium, lanthanum, niobium, tantalum, manganese, cobalt, nickel, magnesium or mixtures thereof, provided that, a primary cation ratio, CR, equals A/B and ranges from more than 0 to about 0.30 wherein

A is a sum of atom % for a cation selected from Ce, Nd, Sm, La or mixtures thereof; and

B is a sum of atom % for a cation selected from Nb, Ta, Mn, Co, Ni, Mg or mixtures thereof

and, further provided, a secondary cation ratio, BR, equals B1/(B2+0.5 Mn) and ranges from 1.8 to 2.2 wherein

B1 is a sum of atom % of an electron donor selected from Nb, Ta or mixtures thereof; and

B2 is a sum of atom % for an electron acceptor selected from Co, Ni, Mg or mixtures thereof Mn is atom % of manganese.

2. The composition of claim 1 wherein the major component ceramic powder particle is of the formula, ABO₃, wherein A is predominantly an alkaline earth metal or mixtures thereof, and B is predominantly titanium, zirconium or mixtures thereof and the mole ratio of A/B is between 0.995 and 1.005.

3. The composition of claim 2 wherein the major component ceramic powder particle is a high purity barium titanate having an average particle size of 2.0 microns or less.

5. The composition of claim 1 or claim 4 further comprising up to 0.10 wt % of silica in the total composition.

6. The composition of claim 1 or claim 4 wherein the Mn cation is between 2 to 10 atom %.

4. A composition for forming a densified dielectric body in a thin dielectric layer with low porosity and having a dissipation factor of 2.5% or less, an insulation resistance of 1000 ohm-Farads or more at 25°

C. and 100 ohm-Farads or more at 125°

C. and a temperature coefficient of capacitance of ±

15% or less within a temperature range of -55°

C. to +125°

C. and consisting essentially of;

(a) 98 to 99 wt % of a high purity barium titanate;

(b) 1 to 2 wt % of minor component additives selected from the group consisting of the oxides of cerium neodymium, niobium, manganese, nickel and mixtures thereof, provided that, a primary cation ratio, CR, equals A/B and ranges from 0.1 to 0.2 wherein

A is Ce cation or Nd cation in atom %; and

B is Nb, Mn or Ni cations in atom % and further provided that a secondary cation ratio, BR, equals

B1/(B2+0.5 Mn) and ranges from 1.9 to 2.1

wherein B1 is Nb cation in atom % and B2 is Ni cation in atom %.