MULTILAYER CERAMIC CAPACITOR

• US 20150340155A1
• Filed: 05/14/2015
• Published: 11/26/2015
• Est. Priority Date: 05/21/2014
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: FUKUNAGA, Daiki, TANAKA, Hideaki, MORIYAMA, Koji
• Granted Patent: US 9,633,788 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01G 4/005 Electrodes
• CPC Class Codes: H01G 4/012 Form of non-self-supporting electrodes
• CPC Class Codes: H01G 4/1218 based on titanium oxides or titanates H01G4/1245 takes precedence
• CPC Class Codes: H01G 4/1227 based on alkaline earth titanates
• CPC Class Codes: H01G 4/248 the terminals embracing or surrounding the capacitive element, e.g. caps H01G4/252 takes precedence
• CPC Class Codes: H01G 4/30 Stacked capacitors H01G4/33 takes precedence

Abstract

A multilayer ceramic capacitor includes a ceramic body and external electrodes provided on opposite end surfaces of the ceramic body. The ceramic body includes an inner layer portion including a plurality of ceramic layers defining inner layers and a plurality of first and second internal electrodes each disposed at an interface of adjacent ones of the ceramic layers defining the inner layers, outer layer portions sandwiching the inner layer portion in a direction in which the layers are stacked, and side margin portions sandwiching the inner layer portion and the outer layer portions in a widthwise direction. The side margin portion includes pores that decrease in number along a direction from inside to outside of the ceramic body.

Claims

1. A multilayer ceramic capacitor comprising:

a ceramic body including a first end surface and a second end surface opposite to the first end surface, a first side surface and a second side surface perpendicular or substantially perpendicular to the first end surface and the second end surface, and a first major surface and a second major surface perpendicular or substantially perpendicular to the first end surface and the first side surface, and including a plurality of dielectric ceramic layers of a perovskite-type compound containing Ba and Ti, and internal electrode layers stacked on one another in a direction extending from the first major surface to the second major surface with a respective one of the plurality of dielectric ceramic layer between each adjacent pair of the internal electrodes; and

external electrodes provided on the ceramic body at the first end surface and the second end surface, respectively;

wherein the internal electrodes includes a first internal electrode and a second internal electrode;

each of the first internal electrode and the second internal electrode extends out to a respective one of the first end surface and the second end surface, and is electrically connected to a respective one of the external electrodes;

when the ceramic body is seen in a direction in which the layers are stacked, the ceramic body includes a region free of the first internal electrode and the second internal electrode defining a side margin portion;

the side margin portion has a multilayer structure.

2. The multilayer ceramic capacitor according to claim 1, wherein the side margin portion has one of a two layer structure and a structure include three or more layers.

3. The multilayer ceramic capacitor according to claim 1, wherein the side margin portion includes an inner portion adjacent to the internal electrode and an outer portion located at the side surfaces of the ceramic body, and the inner portion is smaller in thickness than the outer portion.

4. The multilayer ceramic capacitor according to claim 1, wherein the ceramic body has a rectangular or substantially rectangular parallelepiped shape.

5. The multilayer ceramic capacitor according to claim 1, wherein each of the ceramic layers includes dielectric ceramic grains containing a Ba and Ti-containing perovskite-type compound as a major component and having a perovskite structure and one of Si, MG and Ba present between the grains.

6. The multilayer ceramic capacitor according to claim 1, wherein the side margin portion is made of a dielectric ceramic material including ceramic grains and with a perovskite structure and one of Si, MG and Ba present between the grains.

7. A multilayer ceramic capacitor comprising:

a ceramic body including a first end surface and a second end surface opposite to the first end surface, a first side surface and a second side surface perpendicular or substantially perpendicular to the first end surface and the second end surface, and a first major surface and a second major surface perpendicular or substantially perpendicular to the first end surface and the first side surface, and including a plurality of dielectric ceramic layers of a perovskite-type compound containing Ba and Ti, and internal electrode layers stacked on one another in a direction extending from the first major surface to the second major surface with a respective one of the plurality of dielectric ceramic layer between each adjacent pair of the internal electrodes; and

external electrodes provided on the ceramic body at the first end surface and the second end surface, respectively;

wherein

the internal electrodes includes a first internal electrode and a second internal electrode;

each of the first internal electrode and the second internal electrode extends out to a respective one of the first end surface and the second end surface, and is electrically connected to a respective one of the external electrodes;

when the ceramic body is seen in a direction in which the layers are stacked, the ceramic body includes a region free of the first internal electrode and the second internal electrode defining a side margin portion; and

the side margin portion includes pores that decrease in number along a direction extending from inside to outside of the ceramic body.

8. The multilayer ceramic capacitor according to claim 7, wherein the side margin portion has one of a two layer structure and a structure include three or more layers.

9. The multilayer ceramic capacitor according to claim 7, wherein the side margin portion includes an inner portion adjacent to the internal electrode and an outer portion located at the side surfaces of the ceramic body, and the inner portion is smaller in thickness than the outer portion.

10. The multilayer ceramic capacitor according to claim 7, wherein the ceramic body has a rectangular or substantially rectangular parallelepiped shape.

11. The multilayer ceramic capacitor according to claim 7, wherein each of the ceramic layers includes dielectric ceramic grains containing a Ba and Ti-containing perovskite-type compound as a major component and having a perovskite structure and one of Si, MG and Ba present between the grains.

12. The multilayer ceramic capacitor according to claim 7, wherein the side margin portion is made of a dielectric ceramic material including ceramic grains and with a perovskite structure and one of Si, MG and Ba present between the grains.

13. The multilayer ceramic capacitor according to claim 7, wherein:

each of the dielectric ceramic layers includes ceramic grains with Ba present between the ceramic grains; and

the side margin portion contains Ba at a portion thereof adjacent to the first and second internal electrodes in an amount larger than an amount at a portion thereof located at the side surfaces by larger than about 100% and smaller than about 140%.

14. The multilayer ceramic capacitor according to claim 7, wherein:

each of the dielectric ceramic layers includes ceramic grains with Ba present between the ceramic grains; and

the side margin portion at a portion thereof adjacent to the first and second internal electrodes contains Ba in an amount having a molar ratio larger than about 1.020 and smaller than about 1.040 relative to 1 mol of Ti, and the side margin portion at a portion thereof located at the side surfaces contains Ba in an amount having a molar ratio larger than about 1.000 and smaller than about 1.020 relative to 1 mol of Ti.

15. The multilayer ceramic capacitor according to claim 7, wherein one of the dielectric ceramic layers sandwiched between the first internal electrode and the second internal electrode contains Ba in an amount smaller than the side margin portion.

16. The multilayer ceramic capacitor according to claim 7, wherein

the side margin portion includes an inner portion adjacent to the internal electrode and an outer portion located at the side surfaces of the ceramic body;

and

the inner portion contains Ba in an amount larger than the outer portion.

17. A multilayer ceramic capacitor comprising:

a ceramic body including a first end surface and a second end surface opposite to the first end surface, a first side surface and a second side surface perpendicular or substantially perpendicular to the first end surface and the second end surface, and a first major surface and a second major surface perpendicular or substantially perpendicular to the first end surface and the first side surface, and including a plurality of dielectric ceramic layers of a perovskite-type compound containing Ba and Ti, and internal electrode layers stacked on one another in a direction extending from the first major surface to the second major surface with a respective one of the plurality of dielectric ceramic layer between each adjacent pair of the internal electrodes; and

external electrodes provided on the ceramic body at the first end surface and the second end surface, respectively;

wherein

the internal electrodes includes a first internal electrode and a second internal electrode;

each of the first internal electrode and the second internal electrode extends out to a respective one of the first end surface and the second end surface, and is electrically connected to a respective one of the external electrodes;

when the ceramic body is seen in a direction in which the layers are stacked, the ceramic body includes a region free of the first internal electrode and the second internal electrode defining a side margin portion; and

the side margin portion includes ceramic grains of the ceramic dielectric with Ba between the ceramic grains; and

the ceramic grains decrease in number along a direction extending from inside to outside of the ceramic body.

18. The multilayer ceramic capacitor according to claim 17, wherein the side margin portion has one of a two layer structure and a structure include three or more layers.

19. The multilayer ceramic capacitor according to claim 17, wherein the side margin portion includes an inner portion adjacent to the internal electrode and an outer portion located at the side surfaces of the ceramic body, and the inner portion is smaller in thickness than the outer portion.

20. The multilayer ceramic capacitor according to claim 17, wherein the ceramic body has a rectangular or substantially rectangular parallelepiped shape.

21. The multilayer ceramic capacitor according to claim 17, wherein each of the ceramic layers includes dielectric ceramic grains containing a Ba and Ti-containing perovskite-type compound as a major component and having a perovskite structure and one of Si, MG and Ba present between the grains.

22. The multilayer ceramic capacitor according to claim 17, wherein the side margin portion is made of a dielectric ceramic material including ceramic grains and with a perovskite structure and one of Si, MG and Ba present between the grains.

23. The multilayer ceramic capacitor according to claim 17, wherein:

each of the dielectric ceramic layers includes ceramic grains with Ba present between the ceramic grains; and

the side margin portion contains Ba at a portion thereof adjacent to the first and second internal electrodes in an amount larger than an amount at a portion thereof located at the side surfaces by larger than about 100% and smaller than about 140%.

24. The multilayer ceramic capacitor according to claim 17, wherein:

each of the dielectric ceramic layers includes ceramic grains with Ba present between the ceramic grains; and

the side margin portion at a portion thereof adjacent to the first and second internal electrodes contains Ba in an amount having a molar ratio larger than about 1.020 and smaller than about 1.040 relative to 1 mol of Ti, and the side margin portion at a portion thereof located at the side surfaces contains Ba in an amount having a molar ratio larger than about 1.000 and smaller than about 1.020 relative to 1 mol of Ti.

25. The multilayer ceramic capacitor according to claim 17, wherein one of the dielectric ceramic layers sandwiched between the first internal electrode and the second internal electrode contains Ba in an amount smaller than the side margin portion.

26. The multilayer ceramic capacitor according to claim 17, wherein

the side margin portion includes an inner portion adjacent to the internal electrode and an outer portion located at the side surfaces of the ceramic body;

and

the inner portion contains Ba in an amount larger than the outer portion.