Multilayer Capacitor Dielectric Grain Control for Moisture Reliability
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Solution Overview
Problem
The limited availability and manufacturing technology of barium titanate, a key material for multilayered capacitors, hinders the production of high-reliability capacitors required for advanced electronic devices, particularly in automotive and industrial applications, where high-temperature moisture resistance is crucial.
Innovation Solution
A multilayered capacitor is developed using a barium titanate base material with a uniform mole ratio of barium to titanium, forming dielectric crystal grains with specific size and composition to enhance reliability and withstand voltage characteristics, incorporating a core-shell structure for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barium titanate powder with non-uniform mole ratio is used, then manufacturing is easier and suppliers are more available, but reliability and withstand voltage characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the mole ratio of barium to titanium in the barium titanate base material. Specifically, it sets the Ba/Ti mole ratio within the range of 0.9797 to 0.9943, which optimizes the uniformity of dielectric crystal grains. This parameter control directly improves reliability and withstand voltage characteristics while maintaining manufacturing feasibility through controlled synthesis processes.
Solution Approach 2:
The patent employs composite materials by combining barium titanate base material with specific subcomponents including rare earth elements (Dy2O3: 0.1-1.0 parts by mole, Tb2O3: 0.1-1.0 parts by mole), metal oxides (MnO2: 0-0.2 parts by mole, V2O5: 0-0.15 parts by mole), and other compounds (BaCO3: 1.5-3.3 parts by mole, SiO2: 0.5-4.0 parts by mole, Al2O3: 0.4-0.6 parts by mole, CaCO3: 0-0.8 parts by mole). This composite formulation enhances both reliability and manufacturability.
2Manufacturing precision
If dielectric crystal grains with non-uniform composition are formed, then manufacturing process is simpler, but electrical performance and reliability decrease
Solution Approach 1:
The patent achieves manufacturing precision by controlling the Ba/Ti mole ratio parameter within 0.9797 to 0.9943 and regulating the content of each subcomponent within specific mole ranges. This precise parameter control ensures uniform dielectric crystal grain formation while managing composition control complexity through systematic formulation.
Solution Approach 2:
The patent applies homogeneity by ensuring uniform distribution of barium and titanium atoms in the dielectric crystal grains through controlled synthesis. The consistent mole ratio and uniform subcomponent distribution create homogeneous crystal structures, improving manufacturing precision without excessive complexity.
3Reliability
If conventional barium titanate materials are used, then material availability is higher, but high-temperature moisture resistance characteristics are insufficient
Solution Approach 1:
The patent overcomes material availability limitations by developing a composite formulation that combines barium titanate base material with rare earth elements (Dy, Tb), metal oxides (MnO2, V2O5), and other compounds. This composite approach achieves superior high-temperature moisture resistance while using readily available starting materials in controlled proportions.
Solution Approach 2:
The patent improves high-temperature moisture resistance by changing the compositional parameters of the barium titanate system. Specifically, it optimizes the Ba/Ti mole ratio and incorporates controlled amounts of subcomponents, transforming conventional materials into high-performance compositions with enhanced environmental stability.
Data Source
AI summary
A multilayered capacitor includes a capacitor body including a dielectric layer and an internal electrode, and an external electrode outside the capacitor body, wherein the dielectric layer includes a plurality of dielectric crystal grains, the dielectric crystal grains include barium titanate as a main component, a mole ratio of barium to titanium (Ba/Ti mole ratio) at a center of the dielectric crystal grains is about 0.9797 to about 0.9943, and a coefficient of variation (standard deviation of size/D50) of the dielectric crystal grain size is about 30% and about 43%.