Multilayer Ceramic Capacitor Calcium Gradient Dielectric

Solution Overview

Problem

Multilayer ceramic capacitors face challenges in achieving high capacitance and reliability due to the limitations of barium titanate-based dielectric materials, which exhibit reduced reliability and increased dielectric loss when thinning dielectric layers and internal electrodes, and require improved permittivity and reduced dielectric loss.

Innovation Solution

The use of calcium-doped barium titanate (BCT) in the interfacial portions of the dielectric layers with a higher calcium concentration than the central portions, along with a molar ratio of titanium to calcium in the interfacial portions ranging from 100:1 to 100:20, and barium titanate-based powder without calcium in the central portions, to create a concentration gradient that enhances capacitance and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If barium titanate-based dielectric material is used in multilayer ceramic capacitors, then high permittivity is achieved, but reliability decreases and dielectric loss increases when dielectric layers are thinned

Engineering Contradiction:

ImprovereliabilityVSAvoiddielectric loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating a non-uniform calcium distribution within the dielectric layer. The interfacial portions adjacent to internal electrodes contain calcium at 0.01-0.2 mol ratio (higher concentration), while central portions contain calcium at 0-0.05 mol ratio (lower or zero concentration). This localized variation in material composition allows the interfacial regions to provide improved reliability and reduced dielectric loss, while the central regions maintain high permittivity characteristics of barium titanate.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the chemical composition parameter by introducing calcium doping at varying concentrations throughout the dielectric layer. By controlling the calcium mol ratio to be 0.01-0.2 in interfacial portions and 0-0.05 in central portions, the patent modifies the dielectric properties locally to simultaneously achieve high permittivity, low dielectric loss, and improved reliability.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If dielectric layers are thinned to increase capacitance density, then capacitance increases, but reliability decreases and dielectric loss increases

Engineering Contradiction:

ImprovecapacitanceVSAvoidreliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform calcium distribution within the dielectric layer. The interfacial portions adjacent to internal electrodes contain calcium at 0.01-0.2 mol ratio (higher concentration), while central portions contain calcium at 0-0.05 mol ratio (lower or zero concentration). This localized variation in material composition allows the interfacial regions to provide improved reliability and reduced dielectric loss, while the central regions maintain high permittivity characteristics of barium titanate.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If dielectric layers are thinned to increase capacitance density, then capacitance increases, but dielectric loss increases

Engineering Contradiction:

ImprovecapacitanceVSAvoiddielectric loss

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating a non-uniform calcium distribution within the dielectric layer. The interfacial portions adjacent to internal electrodes contain calcium at 0.01-0.2 mol ratio (higher concentration), while central portions contain calcium at 0-0.05 mol ratio (lower or zero concentration). This localized variation in material composition allows the interfacial regions to provide improved reliability and reduced dielectric loss, while the central regions maintain high permittivity characteristics of barium titanate.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9576729B2Multilayer ceramic electronic component and method of manufacturing the same

Publication Date: 2017.02.21 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

There is provided a multilayer ceramic electronic component including: a ceramic body in which internal electrodes and dielectric layers containing a barium titanate-based compound containing calcium (Ca) are alternately stacked; and external electrodes disposed on outer surfaces of the ceramic body and electrically connected to the internal electrodes. The dielectric layer includes interfacial portions adjacent to the internal electrodes and a central portion disposed between the interfacial portions, the interfacial portion having a calcium (Ca) concentration higher than that of the central portion.