Multilayer Ceramic Capacitor Dielectric Composition for High Capacitance
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in increasing the number of internal electrode layers within restricted dimensions while maintaining capacitance and insulation properties, as reducing dielectric layer thickness compromises reliability.
Innovation Solution
The use of a perovskite-type dielectric layer structure containing Ba, Sr, Zr, Ti, Hf, and optionally Ca and V, with specific mole ratios and particle size, allows for a thinner dielectric layer and improved insulation properties, enabling more internal electrode layers and higher capacitance in compact designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the dielectric layer is reduced to increase the number of internal electrode layers, then the capacitance can be increased within restricted dimensions, but the insulation property deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular composition ratios of the dielectric layer. Specifically, it sets the Sr/(Ba+Ca+Sr) ratio to 0.6-0.95 and the Zr/(Zr+Ti+Hf) ratio to 0.9-0.98, while also controlling the average particle size to 0.8 μm or less. These parameter optimizations enable the dielectric layer to maintain high insulation properties even at reduced thickness of 1 μm or less, thereby resolving the contradiction between increasing the number of internal electrode layers and maintaining insulation reliability.
2Volume of moving object
If the dimensions of the multilayer ceramic capacitor are reduced for downsizing, then the compactness is improved, but the number of internal electrode layers that can be accommodated is restricted
Solution Approach 1:
The patent applies dimensionality change by transitioning to a molecular-level control approach. Instead of merely reducing physical dimensions, it optimizes the dielectric layer thickness to 1 μm or less and controls the average particle size to 0.8 μm or less. This enables packing more internal electrode layers within the same volume, achieving both downsizing and increased capacitance through advanced material science rather than simple geometric scaling.
3Quantity of substance
If the dielectric layer thickness is reduced to accommodate more internal electrode layers, then the capacitance increases, but the reliability cannot be maintained
Solution Approach 1:
The patent applies composite materials by creating a complex multi-element perovskite structure containing Ba, Sr, Ca, Zr, Ti, and Hf in specific ratios. This composite dielectric material, with the formula (SrvBawCax)m(ZryTizHf1-y-z)O3, exhibits superior electrical properties that enable thin dielectric layers (1 μm or less) to maintain high insulation reliability while accommodating more internal electrode layers, thus resolving the contradiction between increased layer count and maintained reliability.
Data Source
AI summary
A multilayer ceramic capacitor that includes a laminate which has a plurality of dielectric layers and a plurality of internal electrode layers respectively laminated. The dielectric layers are a perovskite type structure containing Ba, Sr, Zr, Ti and Hf, and optionally Ca, and further include V, wherein (number of moles of Sr)/(number of moles of Ba+number of moles of Ca+number of moles of Sr) is 0.6 to 0.95, (number of moles of Zr)/(number of moles of Zr+number of moles of Ti+number of moles of Hf) is 0.9 to 0.98, thicknesses of the dielectric layers are 1 μm or less, and an average particle size of dielectric particles constituting the dielectric layers is 0.8 μm or less.