Dielectric Composition for High DC Bias Stability

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Solution Overview

Problem

Conventional dielectric compositions exhibit reduced dielectric constant and increased dielectric loss when subjected to high DC biases, particularly in miniaturized and high-capacity medium- and high-voltage capacitors, failing to meet the requirements for applications with rated voltages exceeding 100 V.

Innovation Solution

A dielectric composition with a main component represented by the formula (BiaNabSrcBad)(αxTi1-x)O3, where α includes Zr and Sn, and specific mole ratios of Bi, Na, Sr, Ba, and α (including Zr/Sn) are optimized to maintain a high dielectric constant and low dielectric loss even at DC biases of 8 V/µm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dielectric compositions are used, then the dielectric element can be manufactured with standard materials, but the dielectric constant is reduced when high DC bias is applied

Engineering Contradiction:
Improvedielectric constant stabilityVSAvoidDC bias performance
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the chemical composition parameters of the dielectric material by incorporating specific metal oxides (Bi2O3, Na2O, SrO, BaO, ZrO2, SnO2, TiO2) in optimized ratios. This compositional parameter change enables the dielectric to maintain stable dielectric constant under high DC bias conditions, resolving the contradiction between standard material usage and DC bias performance adaptability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite dielectric material system combining multiple metal oxides with complementary properties. The synergistic interaction between Bi2O3-Na2O-SrO-BaO system and ZrO2-SnO2-TiO2 system produces a composite material that simultaneously achieves high dielectric constant and excellent DC bias stability, addressing both reliability and adaptability requirements

Inventive Principle:
Principle #40Composite materials

2Productivity

If the dielectric layer is made thinner to achieve miniaturization, then the capacitance increases, but the dielectric constant decreases under high DC bias

Engineering Contradiction:
Improveminiaturization and capacityVSAvoiddielectric constant
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies the dielectric material's chemical composition parameters to achieve superior electrical properties that compensate for the reduced thickness. By optimizing the ratios of Bi2O3, Na2O, SrO, BaO, ZrO2, SnO2, and TiO2, the material achieves enhanced dielectric constant and DC bias stability, enabling thin-layer designs to maintain high capacitance without suffering from DC bias-induced performance degradation

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If high DC bias is applied to achieve high voltage operation, then the rated voltage requirement is met, but the dielectric constant is reduced and dielectric loss increases

Engineering Contradiction:
Improverated voltageVSAvoiddielectric constant and loss
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent employs a composite dielectric system combining Bi2O3-Na2O-SrO-BaO perovskite phase with ZrO2-SnO2-TiO2 modifiers. This composite structure provides both high breakdown voltage capability for high-voltage operation and maintained dielectric constant with low loss under DC bias, resolving the contradiction between voltage stress requirements and dielectric performance reliability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the chemical composition parameters including the ratios of Bi2O3 (0.1-0.4), Na2O (0.1-0.4), SrO (0.2-0.7), BaO (0.02-0.24), ZrO2 (0.02-0.24), SnO2 (0.02-0.24), and TiO2 (balance) to achieve simultaneous improvement in breakdown voltage, dielectric constant stability, and low dielectric loss under high DC bias conditions

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

The composition achieves a dielectric constant of 800 or greater and dielectric loss of 4% or less when a DC bias of 8 V/µm is applied, suitable for high-voltage capacitors, while being lead-free and environmentally friendly.

Implementation Method 1

the dielectric composition according to the present invention has a main component represented by (BiaNabSrcBad) (αxTi1-x)O3... it is possible to achieve a relatively high dielectric constant of 800 or greater and a relatively low dielectric loss of 4% or less when a DC bias of at least 8 V/μm is applied

Methodology Applied
Scientific EffectDielectric Permittivity: Dielectric Permittivity

Data Source

PatentEP3191428B8Dielectric composition, dielectric element, electronic component and laminated electronic component
Publication Date: 2018.12.26 TDK ELECTRONICS AG

AI summary

The aim of the present invention lies in providing a dielectric composition which has a relatively high dielectric constant of 800 or greater, and which has relatively low dielectric loss of 4% or less when a DC bias of at least 8 V/ym is applied, and also in providing a dielectric element employing said dielectric composition, an electronic component, and a laminated electronic component. A dielectric composition having a main component represented by (BiaNabSrcBad) (αxTi1-x) O3, characterized in that a is at least one selected from Zr and Sn; and a, b, c, d and x satisfy the following: 0.140≤a<0.390, 0.140≤b<0.390, 0.200≤c<0.700, 0.020≤d<0.240, 0.020≤x<0.240 and 0.950<a+b+c+d≤l.050.