Composite Oxide Structure for High Dielectric Constant and Breakdown Strength

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Solution Overview

Problem

Conductor/insulator composite materials face a trade-off between achieving high apparent dielectric constant and dielectric breakdown strength, with existing materials struggling to simultaneously enhance both properties.

Innovation Solution

A composite structure comprising a conductor region made from a first oxide and an insulator region made from a second oxide, with a hetero structure formed between them, where both oxides have a perovskite structure, and specific combinations such as LaNiO3/SrRuO3 with (Ba,Sr)TiO3, (Bi0.5Na0.5)TiO3, or (Bi0.5K0.5)TiO3 are used to create a dielectric element with improved properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the proportion of insulators is reduced to increase capacitance, then the electrostatic capacitance property is improved, but the dielectric breakdown strength property deteriorates

Engineering Contradiction:

ImprovecapacitanceVSAvoiddielectric breakdown strength

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention uses a composite material consisting of a semiconductor particle and a grain boundary phase with different compositions and properties. The semiconductor particle provides high capacitance while the grain boundary phase maintains dielectric breakdown strength, resolving the contradiction between increasing capacitance and maintaining reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention creates local quality differences by forming a grain boundary phase with specific composition (different from the semiconductor particle) at the grain boundaries. This localized modification allows the bulk material to have high capacitance while the grain boundaries provide enhanced dielectric breakdown strength.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If the composition is controlled to enhance apparent dielectric constant, then the electrostatic capacitance property is improved, but the dielectric breakdown strength property becomes insufficient

Engineering Contradiction:

Improveapparent dielectric constantVSAvoiddielectric breakdown strength

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention employs a composite structure where semiconductor particles with high dielectric constant are combined with a grain boundary phase. This composite approach allows the bulk semiconductor to contribute to high apparent dielectric constant while the grain boundary phase ensures adequate dielectric breakdown strength.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The grain boundary phase acts as an intermediary between adjacent semiconductor particles. It mediates the electrical properties by providing a transition zone that maintains high overall dielectric constant while preventing direct breakdown paths through the semiconductor particles.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11282643B2Composite structure, fired body having composite structure, powder including particle having composite structure, and dielectric element including dielectric having composite structure

Publication Date: 2022.03.22 TDK CORP

AI summary

A composite structure including a conductor region that is configured from a first oxide, and an insulator region that is configured from a second oxide and that surrounds the conductor region, wherein the first oxide and the second oxide are in hetero structure with each other. A powder and a fired body each having such a composite structure are also preferable.