Multilayer Ceramic Capacitor Core-Shell Grain Structure
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving miniaturization and high capacity while maintaining reliability, high-temperature withstand voltage, and DC-bias properties due to the reduction in dielectric layer thickness, which affects their dielectric constant and capacitance under high electric fields.
Innovation Solution
A multilayer electronic component with a dielectric layer comprising first and second grains having specific core-shell structures and atomic ratios, where the first grain occupies 28.3-82.3% of the area, and a dielectric composition based on BaTiO3 with a core-shell structure, optimizing the atomic ratios and molar ratios of Sn and Hf to enhance room-temperature dielectric constant, DC-bias properties, and high-temperature withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the dielectric layer is decreased to achieve miniaturization and high capacity, then the size and capacitance are improved, but the reliability and high-temperature withstand voltage properties deteriorate
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell region has a different composition (higher Sn or Hf content) than the core region. This localized compositional variation allows the shell to provide enhanced dielectric properties and reliability, while the core maintains the basic BaTiO3 structure. The shell thickness and composition are specifically optimized to improve high-temperature withstand voltage properties without compromising the overall miniaturization goals.
Solution Approach 2:
The patent employs composite materials by combining BaTiO3 with Sn or Hf elements in a core-shell configuration. The composite structure integrates the high dielectric constant of BaTiO3 with the enhanced stability and withstand voltage properties provided by Sn or Hf doping in the shell region. This composite approach enables simultaneous achievement of miniaturization, high capacity, and improved reliability.
2Volume of moving object
If the thickness of the dielectric layer is decreased to achieve miniaturization, then the capacity increases, but the DC-bias properties worsen
Solution Approach 1:
The core-shell structure with localized Sn or Hf enrichment in the shell region addresses DC-bias properties by creating a gradient composition that stabilizes the dielectric constant under applied DC fields. The shell acts as a protective layer that maintains electrical properties even when thin dielectric layers are used for miniaturization.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the atomic ratio of Sn or Hf in the shell region (2*Sn/(Ba+Ti+Sn) or 2*Hf/(Ba+Ti+Hf) = 1.0-5.0 at%) and controlling the shell thickness ratio (10-50 nm) to optimize DC-bias properties. These parameter optimizations enable thin dielectric layers to maintain stable capacitance under DC-bias conditions.
3Volume of moving object
If the dielectric layer thickness is reduced to achieve miniaturization, then the capacitance density increases, but the room-temperature dielectric constant and high-temperature withstand voltage properties decrease
Solution Approach 1:
The core-shell structure implements local quality by concentrating Sn or Hf elements in the shell region, which locally enhances the dielectric constant and withstand voltage properties at the grain boundaries and surfaces where electrical stress is highest. This localized enhancement compensates for the overall reduction in dielectric layer thickness.
Solution Approach 2:
The composite BaTiO3-Sn or BaTiO3-Hf structure with core-shell morphology provides a synergistic effect where the core contributes to high dielectric constant and the shell contributes to high-temperature stability and withstand voltage properties, enabling thin dielectric layers to maintain excellent electrical characteristics.
Data Source
AI summary
A multilayer 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, wherein the dielectric layer includes first and second grains, wherein the first grain has a core-shell structure including a shell having an atomic ratio of 2*Sn/(Ba+Ti+Sn) or 2*Hf/(Ba+Ti+Hf) to be 1.0% or more and 5.0% or less, and a core having an atomic ratio of 2*Sn/(Ba+Ti+Sn) and 2*Hf/(Ba+Ti+Hf) to be less than 1.0%, and the second grain has an atomic ratio of 2*Sn/(Ba+Ti+Sn) and 2*Hf/(Ba+Ti+Hf) to be less than 1.0%, and wherein an area occupied by the first grain in an entire area of the first and second grains is 28.3-82.3%.