Core-Dual Shell Dielectric Grains for MLCC Reliability and TCC
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Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in maintaining reliability, insulation resistance, and temperature coefficient of capacitance (TCC) characteristics, especially when layers are thinned for higher capacity or when subjected to high voltages in severe environments.
Innovation Solution
The ceramic electronic component incorporates a dielectric layer with dielectric grains having a core-dual shell structure, where the second shell has a higher concentration of rare earth elements than the first shell, optimizing the concentration ratio between 1.3 and 3.8 times to enhance high temperature lifespan and TCC characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If layers are thinned to increase capacity, then capacitance increases, but reliability and insulation resistance deteriorate
Solution Approach 1:
The patent applies local quality by creating a core-dual shell structure where different regions of the dielectric grain have different compositions. The core contains barium titanate with specific dopants, the first shell has a different rare earth element concentration, and the second shell has an even higher rare earth element concentration (1.3 to 3.8 times that of the first shell). This gradient structure provides localized protection at grain boundaries while maintaining bulk dielectric properties, thereby improving reliability and insulation resistance even when layers are thinned for higher capacitance.
2Reliability
If rare earth element is added to suppress oxygen vacancies, then reliability improves, but high temperature lifespan characteristics and TCC characteristics deteriorate
Solution Approach 1:
The patent uses local quality by concentrating rare earth elements specifically in the shell regions (first and second shells) surrounding the core, rather than uniformly distributing them throughout the entire dielectric grain. The second shell has a rare earth element concentration 1.3 to 3.8 times that of the first shell, creating a gradient that provides oxygen vacancy suppression at grain boundaries while keeping the core region optimized for high temperature stability and TCC characteristics.
Solution Approach 2:
The patent segments the dielectric grain into distinct regions: a core and a dual shell structure. This segmentation allows different functional optimization in each region - the core for bulk dielectric properties and the shells for grain boundary protection. By dividing the grain structure, the patent achieves both improved reliability through oxygen vacancy suppression and maintained high temperature lifespan characteristics.
3Reliability
If rare earth element concentration is increased to improve reliability, then oxygen vacancy generation is suppressed, but TCC characteristic deteriorates
Solution Approach 1:
The patent applies local quality by creating a gradient distribution of rare earth elements in the dual shell structure. The first shell has a moderate rare earth element concentration, while the second shell has a higher concentration (1.3 to 3.8 times that of the first shell). This localized concentration strategy suppresses oxygen vacancies at grain boundaries to improve insulation resistance while avoiding excessive rare earth element content that would deteriorate TCC characteristics.
Data Source
AI summary
A ceramic electronic component includes a body including a dielectric layer and an internal electrode, and an external electrode disposed on the body and connected to the internal electrode. The dielectric layer includes a plurality of dielectric grains, and at least one of the plurality of dielectric grains has a core-dual shell structure having a core and a dual shell. The dual shell includes a first shell surrounding at least a portion of the core, and a second shell surrounding at least a portion of the first shell, and a concentration of a rare earth element included in the second shell is more than 1.3 times to less than 3.8 times a concentration of a rare earth element included in the first shell.