Dielectric Composition for Multilayer Ceramic Capacitors
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Solution Overview
Problem
The challenge is to develop a dielectric composition with high permittivity and reliability for multilayer ceramic capacitors that maintain stable capacitance and withstand high temperatures without compromising on size, strength, and reliability, as the thinness and high pressure of these capacitors can lead to deteriorated DC-bias and withstand voltage characteristics.
Innovation Solution
A dielectric composition comprising a main ingredient represented by Bam(Ti(1-y)My)O3, where M is a transition metal, and accessory ingredients such as magnesium, silicon, dysprosium, and aluminum, which are carefully balanced to achieve high permittivity and reliability, with the transition metal content ratio and accessory ingredient proportions optimized to prevent particle growth and ensure stable sintering temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the grain size of the main ingredient is decreased to avoid structural defects, then reliability is improved, but permittivity decreases and capacitance temperature characteristics become difficult to implement
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric layer by introducing a specific compound (BaMgAl10O17 or BaMgAl10O17-SiO2) containing six-coordinate aluminum. This compositional parameter change allows the system to achieve both fine grain size for reliability and sufficient permittivity for capacitance, resolving the contradiction between reliability and permittivity.
Solution Approach 2:
The patent uses a composite dielectric material system consisting of barium titanate (BaTiO3) as the main ingredient combined with BaMgAl17O17 or BaMgAl10O17-SiO2 as an additive. This composite approach allows the fine-grained BaTiO3 to provide reliability while the composite structure maintains adequate permittivity levels.
2Length of moving object
If the dielectric layer is made thinner to reduce capacitor size, then miniaturization is achieved, but DC-bias and withstand voltage characteristics deteriorate
Solution Approach 1:
The patent changes the chemical composition by incorporating BaMgAl10O17 or BaMgAl10O17-SiO2 compounds with six-coordinate aluminum into the dielectric layer. This compositional modification enhances the material's electrical breakdown strength and DC-bias characteristics, allowing thinner dielectric layers to maintain reliable withstand voltage performance.
3Quantity of substance
If high pressure is applied to increase capacitance, then capacitance increases, but structural defects increase and reliability decreases
Solution Approach 1:
The patent modifies the dielectric composition by adding BaMgAl10O17 or BaMgAl10O17-SiO2 compounds, which contain six-coordinate aluminum. This compositional change enables the dielectric layer to withstand high pressure during manufacturing while preventing structural defects, thereby maintaining both high capacitance and high reliability.
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 high permittivity and reliability, maintaining stable capacitance and insulation resistance across a wide temperature range, while preventing particle growth and ensuring reliable performance under high electric field intensity.
Implementation Method 1
the main ingredient is represented by Bam(Ti(1-y)My)O3, where M is a transition metal, and y is 0.001 to 0.010
Implementation Method 2
the transition metal content ratio and accessory ingredient proportions optimized to prevent particle growth and ensure stable sintering temperatures
Data Source
AI summary
A dielectric composition includes a main ingredient and accessory ingredients. The main ingredient is represented by Bam(Ti(1-y)My)O3 (0.990<m<1.015, 0.001≦y≦0.010), where M is a transition metal including at least one of a pentavalent transition metal and a trivalent transition metal.