Core-Shell Dielectric Grains for Reliable High-Capacitance MLCCs
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Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in achieving high capacitance and reliability while maintaining a small size, particularly under harsh conditions, due to the limitations of dielectric layer thickness and the core-shell structure of dielectric grains.
Innovation Solution
A multilayer electronic component is designed with a dielectric layer comprising dielectric grains that have a core-shell structure, where the core occupies 15% to 19% of the average thickness of the dielectric layer, and the shell includes rare earth elements and tin, with an average atomic percentage of 0.8 at% to 1.2 at%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the dielectric layer is decreased to achieve high capacitance in a small volume, then the capacitance per unit volume increases, but the reliability under high temperature stress deteriorates
Solution Approach 1:
The dielectric grain is divided into core and shell regions with different compositions and properties. The core region has high dielectric constant for capacitance, while the shell region has high resistance for reliability, creating local quality differentiation that resolves the contradiction between capacitance and reliability
Solution Approach 2:
The dielectric grain is constructed as a composite structure with core and shell regions having different material compositions. The core contains specific elements for high dielectric constant, while the shell contains different elements for high resistance, achieving both capacitance and reliability requirements simultaneously
2Reliability
If the core-shell structure is optimized to improve reliability, then the resistance increases, but the dielectric constant may be compromised
Solution Approach 1:
The thickness ratio of core to shell is precisely controlled within 70-93% to optimize the balance between dielectric constant and resistance. This parameter optimization ensures that the core region contributes sufficiently to capacitance while the shell region provides adequate resistance for reliability
Solution Approach 2:
Different regions of the dielectric grain are assigned different properties: the core region is optimized for high dielectric constant to maintain capacitance, while the shell region is optimized for high resistance to improve reliability, resolving the contradiction through spatial differentiation
Data Source
AI summary
A multilayer electronic component includes a body including a dielectric layer and internal electrodes; and external electrodes disposed on the body, wherein the dielectric layer includes a plurality of dielectric grains, and at least one of the plurality of dielectric grains has a core-shell structure including a core and a shell surrounding at least a portion of the core, wherein a percentage of an average diameter of the core based on an average thickness of the dielectric layer is 15% or more and 19% or less, and wherein the shell includes rare earth elements and tin (Sn), and an average atomic percentage of a sum of rare earth elements and tin (Sn) in the shell is 0.8 at % or more and 1.2 at % or less.