BaTiO3 Dielectric Composition for Stable MLCC Capacitance Aging

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Solution Overview

Problem

Ceramic electronic devices with base metal internal electrode layers face reliability issues due to oxygen defects in the dielectric layer, which are exacerbated by annealing processes and can lead to reduced electrostatic capacity and capacity aging.

Innovation Solution

Incorporating rare earth elements like Gd, Tb, Dy, Ho, Y, and Er into both the A and B sites of BaTiO3 dielectric layers, allowing for high electrostatic capacity while suppressing chronological changes in capacity without oxidizing the internal electrode layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an annealing process is performed to remove oxygen defects in the dielectric layer, then reliability is improved, but oxygen is supplied and dispersed causing capacity aging

Engineering Contradiction:

Improvedevice reliabilityVSAvoidcapacity stability over time

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent converts the harmful effect of oxygen supply during annealing (which causes capacity aging) into a beneficial effect by controlling the oxidation of the internal electrode layer. The oxidation of base metal internal electrodes is utilized to suppress oxygen defect formation in the dielectric layer, thereby improving reliability without causing capacity aging. This transforms the harmful oxygen supply into a useful mechanism for defect suppression.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the oxidation state parameter of the internal electrode layer from reduced to oxidized condition. By controlling the oxidation of base metal internal electrodes during the annealing process, the patent achieves suppression of oxygen defects in the dielectric layer while maintaining capacity stability. This parameter change allows simultaneous improvement of reliability and capacity stability.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If base metal is used for internal electrode layer to reduce cost, then manufacturing cost is reduced, but oxygen defects appear in the dielectric layer degrading reliability

Engineering Contradiction:

Improvemanufacturing costVSAvoiddevice reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent converts the harmful tendency of base metal to form oxygen defects into a beneficial mechanism. By allowing controlled oxidation of the base metal internal electrode layer, the patent suppresses oxygen defect formation in the dielectric layer. This converts the inherent disadvantage of base metal into a useful mechanism for improving reliability while maintaining cost effectiveness.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the oxidation state parameter of the base metal internal electrode from reduced to oxidized condition. This parameter change suppresses oxygen defect formation in the dielectric layer, thereby improving reliability while maintaining the cost advantage of using base metal instead of noble metals.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If internal electrode layer is oxidized to suppress oxygen defects, then reliability is improved, but continuous modulus of internal electrode layer is reduced and electrostatic capacity decreases

Engineering Contradiction:

Improvedevice reliabilityVSAvoidcontinuous modulus of internal electrode layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the oxidation parameter of the internal electrode layer to achieve a balance between reliability and mechanical strength. By controlling the degree and conditions of oxidation, the patent suppresses oxygen defects in the dielectric layer (improving reliability) while minimizing the reduction in continuous modulus of the internal electrode layer.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach maintains high electrostatic capacity and reduces capacity aging by controlling defect dipoles and grain growth, enhancing the reliability of ceramic electronic devices.

Implementation Method 1

a rare earth element that is at least one of Gd, Tb, Dy, Ho, Y and Er is solid-solved in both of an A site and a B site of BaTiO3 of the dielectric layers

Methodology Applied

Scientific EffectSolid solution: Solid Solution Strengthening

Data Source

PatentUS12080482B2Ceramic electronic device including a rare earth element solid-solved in barium titanate of dielectric layers

Publication Date: 2024.09.03 TAIYO YUDEN KK

AI summary

A ceramic electronic device includes: a multilayer chip in which each of dielectric layers and each of internal electrode layers are alternately stacked, a main component of the dielectric layers being BaTiO3, wherein a rare earth element that is at least one of Gd, Tb, Dy, Ho, Y and Er is solid-solved in both of an A site and a B site of BaTiO3 of the dielectric layers.