Multilayer ceramic capacitor and method for producing the same

Patent metadata

Field	Value
Publication number	US-2016118188-A1
Application number	US-201514980370-A
Country	US
Kind code	A1
Filing date	Dec 28, 2015
Priority date	Sep 18, 2013
Publication date	Apr 28, 2016
Grant date	—

Abstract

A dielectric ceramic that forms dielectric ceramic layers of a multilayer ceramic capacitor contains a Ba and Ti containing perovskite compound, Ca, R (R denotes a rare earth element, such as La), M (M denotes Mn or the like), and Si. The Ca content ranges from 0.5 to 2.5 molar parts, the R content ranges from 0.5 to 4 molar parts, the M content ranges from 0.5 to 2 molar parts, and the Si content ranges from 1 to 4 molar parts, based on 100 molar parts of Ti. In perovskite crystal grains, the Ca diffusion depth is 10% or less of the average grain size of the crystal grains, and the Ca concentration in a Ca diffusion region is 0.2 to 5 molar parts higher than the Ca concentration near the center of each of the crystal grains.

First claim

1 . A multilayer ceramic capacitor comprising:
a multilayer body including a plurality of stacked dielectric ceramic layers and a plurality of internal electrodes disposed along a plurality of interfaces between the dielectric ceramic layers, the dielectric ceramic layers comprising a dielectric ceramic containing crystal grains and crystal grain boundaries; and an outer electrode disposed on a surface of the multilayer body and electrically connected to specific internal electrodes thereamong, wherein the multilayer body contains
a perovskite compound containing Ba and Ti, and
Ca, R, M, and Si,
wherein R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Y, and
M is at least one of Mn, Co, Fe, Cr, Cu, Mg, Al, V, Mo, and W,
the multilayer body contains, with respect to 100 molar parts of Ti,
0.5 molar parts to 2.5 molar parts of Ca,
0.5 molar parts to 4 molar parts of R,
0.5 molar parts to 2 molar parts of M, and
1 molar parts to 4 molar parts of Si,
the crystal grains include perovskite crystal grains composed mainly of the perovskite compound, wherein, when a Ca concentration in the perovskite crystal grains is represented by a relative Ca concentration with respect to 100 molar parts of Ti at a point of measurement, the crystal grains have a Ca diffusion depth in a range of 10% or less of an average grain size of the crystal grains, the Ca diffusion depth being defined as a distance of a region that has the Ca concentration of 0.1 molar parts or greater with respect to the Ca concentration at a center of the crystal grain, the distance extending from the crystal grain boundary toward the center of the crystal grain, and a difference between an average Ca concentration in the region of the Ca diffusion depth and the Ca concentration at the center of the crystal grain ranges from 0.2 molar parts to 5 molar parts.

2 . The multilayer ceramic capacitor according to claim 1 , wherein R is diffused in the region of the Ca diffusion depth.

3 . The multilayer ceramic capacitor according to claim 1 , wherein each of the dielectric ceramic layers has a thickness of 0.8 μm or less on average.

4 . A multilayer ceramic capacitor comprising:
a multilayer body including a plurality of stacked dielectric ceramic layers and a plurality of internal electrodes disposed along a plurality of interfaces between the dielectric ceramic layers, the dielectric ceramic layers being formed of a dielectric ceramic containing crystal grains and crystal grain boundaries; and an outer electrode disposed on a surface of the multilayer body and electrically connected to specific internal electrodes thereamong, wherein the multilayer body contains
a perovskite compound containing Ba and Ti, and
Ca, R, M, and Si,
wherein R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Y, and
M is at least one of Mn, Co, Fe, Cr, Cu, Mg, Al, V, Mo, and W,
a solution of the multilayer body contains, with respect to 100 molar parts of Ti,
0.5 molar parts to 2.5 molar parts of Ca,
0.5 molar parts to 4 molar parts of R,
0.5 molar parts to 2 molar parts of M, and
1 molar parts to 4 molar parts of Si,
the crystal grains include perovskite crystal grains composed mainly of the perovskite compound, and wherein, when a Ca concentration in the perovskite crystal grains is represented by a relative Ca concentration with respect to 100 molar parts of Ti at a point of measurement, the crystal grains have a Ca diffusion depth in a range of 10% or less of an average grain size of the crystal grains, the Ca diffusion depth being defined as a distance of a region that has the Ca concentration of 0.1 molar parts or greater with respect to the Ca concentration at a center of the crystal grain, the distance extending from the crystal grain boundary toward the center of the crystal grain, and a difference between an average Ca concentration in the region of the Ca diffusion depth and the Ca concentration at the center of the crystal grain ranges from 0.2 molar parts to 5 molar parts.

5 . The multilayer ceramic capacitor according to claim 4 , wherein R is diffused in the region of the Ca diffusion depth.

6 . The multilayer ceramic capacitor according to claim 4 , wherein each of the dielectric ceramic layers has a thickness of 0.8 μm or less on average.

7 . A multilayer ceramic capacitor comprising:
a multilayer body including a plurality of stacked dielectric ceramic layers and a plurality of internal electrodes disposed along a plurality of interfaces between the dielectric ceramic layers, the dielectric ceramic layers being formed of a dielectric ceramic containing crystal grains and crystal grain boundaries; and an outer electrode disposed on a surface of the multilayer body and electrically connected to specific internal electrodes thereamong, wherein the dielectric ceramic layers contain
a perovskite compound containing Ba and Ti, and
Ca, R, M, and Si,
wherein R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Y, and
M is at least one of Mn, Co, Fe, Cr, Cu, Mg, Al, V, Mo, and W,
the dielectric ceramic layers contain, with respect to 100 molar parts of Ti,
0.5 molar parts to 2.5 molar parts of Ca,
0.5 molar parts to 4 molar parts of R,
0.5 molar parts to 2 molar parts of M, and
1 molar parts to 4 molar parts of Si,
the crystal grains include perovskite crystal grains composed mainly of the perovskite compound, and when a Ca concentration in the perovskite crystal grains is represented by a relative Ca concentration with respect to 100 molar parts of Ti at a point of measurement, the crystal grains have a Ca diffusion depth in a range of 10% or less of an average grain size of the crystal grains, the Ca diffusion depth being defined as a distance of a region that has the Ca concentration of 0.1 molar parts or greater with respect to the Ca concentration at a center of the crystal grain, the distance extending from the crystal grain boundary toward the center of the crystal grain, and a difference between an average Ca concentration in the region of the Ca diffusion depth and the Ca concentration at the center of the crystal grain ranges from 0.2 molar parts to 5 molar parts.

8 . The multilayer ceramic capacitor according to claim 7 , wherein R is diffused in the region of the Ca diffusion depth.

9 . The multilayer ceramic capacitor according to claim 7 , wherein each of the dielectric ceramic layers has a thickness of 0.8 μm or less on average.

10 . A multilayer ceramic capacitor comprising:
a multilayer body including a plurality of stacked dielectric ceramic layers and a plurality of internal electrodes disposed along a plurality of interfaces between the dielectric ceramic layers, the dielectric ceramic layers being formed of a dielectric ceramic containing crystal grains and crystal grain boundaries; and an outer electrode disposed on a surface of the multilayer body and electrically connected to specific internal electrodes thereamong, wherein the multilayer body contains
a perovskite compound containing Ba, Ca, and Ti, and
Ca, R, M, and Si,
wherein R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Y, and
M is at least one of Mn, Co, Fe, Cr, Cu, Mg, Al, V, Mo, and W,
the multilayer body contains, with respect to 100 molar parts of Ti,
2.5 molar parts to 15 molar parts of Ca,
0.5 molar parts to 4 molar parts of R,
0.5 molar parts to 2 molar parts of M, and
1 molar parts to 4 molar parts of Si,
the crystal grains include perovskite crystal grains composed mainly of the perovskite compound, and wherein, when a Ca concentration in the perovskite crystal grains is represented by a relative Ca concentration with respect to 100 mo

Assignees

• Murata Manufacturing Co

Inventors

• Wada Nobuyuki

Classifications

• H01G4/1209

  characterised by the ceramic dielectric material (H01G4/1272, H01G4/1281 take precedence) · CPC title

• C04B2237/68

  Forming laminates or joining articles wherein at least one substrate contains at least two different parts of macro-size, e.g. one ceramic substrate layer containing an embedded conductor or electrode · CPC title

• C04B2237/346

  Titania or titanates · CPC title

• C04B2235/85

  Intergranular or grain boundary phases · CPC title

• C04B2235/6584

  at an oxygen percentage below that of air · CPC title