Fe-Gradient Capacitor Structure to Preserve Capacitance
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Solution Overview
Problem
Thinner dielectric layers in capacitors reduce insulation reliability and can lead to a decrease in effective capacitance due to Fe diffusion, which is mitigated by forming intermediate layers containing Fe between dielectric layers and internal electrode layers.
Innovation Solution
A capacitor design with intermediate layers containing Fe at specific concentrations between dielectric and internal electrode layers, ensuring a higher Schottky barrier to enhance insulation reliability and prevent capacitance loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intermediate layers containing Fe are formed between dielectric layers and internal electrode layers to increase Schottky barrier, then insulation reliability is improved, but Fe diffuses into dielectric layers causing decrease in effective capacitance
Solution Approach 1:
The patent applies local quality by creating an intermediate layer with non-uniform Fe concentration distribution. The Fe concentration is higher at the interface between the internal electrode layer and dielectric layer, and decreases toward the center of the intermediate layer. This localized concentration gradient ensures sufficient Schottky barrier formation at the critical interface while minimizing Fe diffusion into the dielectric layer, thus resolving the contradiction between insulation reliability and effective capacitance.
Solution Approach 2:
The patent employs parameter changes by controlling the Fe concentration in the intermediate layer within a specific range (0.01 at% to 5 at%). By optimizing this concentration parameter, the patent achieves a balance between forming adequate Schottky barrier for insulation reliability and preventing excessive Fe diffusion that would reduce effective capacitance. The specific concentration range represents the optimized parameter that resolves the technical contradiction.
2Quantity of substance
If amount of Fe added to raw material is reduced to prevent Fe diffusion into dielectric layers, then effective capacitance is maintained, but sufficient intermediate layers are not formed resulting in degraded insulation reliability
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through non-uniform Fe concentration distribution in the intermediate layer. The Fe concentration is designed to be higher at the interface region where Schottky barrier formation is critical, and lower toward the center and dielectric interface. This localized concentration strategy ensures adequate intermediate layer formation for insulation reliability while using minimal total Fe content to maintain effective capacitance.
Solution Approach 2:
The patent applies parameter changes by establishing a specific Fe concentration range (0.01 at% to 5 at%) in the intermediate layer. This optimized parameter ensures that sufficient intermediate layer is formed to provide insulation reliability while the controlled concentration prevents excessive Fe diffusion that would compromise effective capacitance. The parameter optimization resolves the trade-off between the two conflicting requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design inhibits capacitance decrease and improves insulation reliability by maintaining effective capacitance while extending the service life of the capacitor.
Implementation Method 1
intermediate layers containing trace amounts of metallic elements between the dielectric layers and the internal electrode layers, so that the intermediate layers can increase the Schottky barrier between the dielectric layers and the internal electrode layers
Implementation Method 2
If intermediate layers containing Fe are formed between the dielectric layers and the internal electrode layers, Fe is likely to diffuse into the dielectric layers
Data Source
AI summary
One object is to inhibit the reduction of effective capacitance of a capacitor that includes an intermediate layer containing Fe. An aspect of the present disclosure provides a capacitor including a body, a first external electrode provided on the body, and a second external electrode provided on the body. The body includes: a first internal electrode layer; a second internal electrode layer; a dielectric layer disposed between the first and second internal electrode layers; and a first intermediate layer disposed between the first internal electrode layer and the dielectric layer, the first intermediate layer containing Fe at a first concentration. The first concentration is from 0.2 at % to 5 at %. The dielectric layer contains Fe at a second concentration, and the second concentration is less than 1 at %. An Fe concentration ratio, which represents a ratio of the first concentration to the second concentration, is greater than 1.