Laminated Ceramic Capacitor Fe Gradient for Insulation Reliability
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Solution Overview
Problem
The miniaturization of laminated ceramic capacitors leads to degraded insulation reliability and reduced effective capacitance due to the diffusion of Fe from intermediate layers into dielectric layers, necessitating a balance between capacitance and insulation reliability.
Innovation Solution
Incorporating Fe at specific concentrations in both internal electrode layers and intermediate layers, with a Ni-plated external electrode, to enhance the Schottky barrier and suppress hydrogen absorption, thereby maintaining capacitance and improving insulation reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Fe is added to the intermediate layer to increase the Schottky barrier, then insulation reliability is improved, but Fe diffuses into the dielectric layer causing effective capacitance to decrease
Solution Approach 1:
The patent applies local quality by creating an intermediate layer with a specific Fe concentration gradient - higher Fe concentration at the interface with the internal electrode layer and lower concentration toward the dielectric layer. This localized distribution of Fe ensures the Schottky barrier is formed where needed (at the electrode-dielectric interface) while minimizing Fe diffusion into the dielectric layer, thus resolving the contradiction between improving insulation reliability and maintaining effective capacitance.
Solution Approach 2:
The patent changes the concentration parameter of Fe in the intermediate layer, specifically controlling it to be 0.01 at % or greater but not exceeding certain limits. By optimizing this concentration parameter, the patent achieves sufficient Schottky barrier formation for improved insulation reliability while preventing excessive Fe diffusion that would reduce effective capacitance, thus resolving the technical contradiction.
2Quantity of substance
If the amount of Fe added to the raw material is reduced to prevent capacitance decrease, then effective capacitance is maintained, but the Schottky barrier cannot be sufficiently increased causing insulation reliability to drop
Solution Approach 1:
The patent applies local quality by concentrating Fe in the intermediate layer rather than distributing it throughout the dielectric layer. This localized concentration achieves the necessary Schottky barrier effect for insulation reliability without requiring high overall Fe content that would diffuse into and degrade the dielectric layer, thus maintaining effective capacitance while improving insulation reliability.
Solution Approach 2:
The intermediate layer acts as an intermediary between the internal electrode layer and the dielectric layer. It contains the Fe that forms the Schottky barrier, preventing direct contact between Fe and the dielectric layer. This intermediary structure allows sufficient Fe to be present for insulation reliability while blocking Fe diffusion into the dielectric layer, thereby maintaining effective capacitance.
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 solution effectively prevents a decrease in effective capacitance while enhancing insulation reliability by optimizing Fe concentrations and utilizing a Ni-plated layer to manage hydrogen absorption, ensuring stable capacitor performance.
Implementation Method 1
improve the insulation reliability of the capacitors by providing intermediate layers containing trace amounts of metal 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
Incorporating Fe at specific concentrations in both internal electrode layers and intermediate layers, with a Ni-plated external electrode, to enhance the Schottky barrier and suppress hydrogen absorption
Data Source
AI summary
A capacitor includes a body, a first external electrode provided on the body, and a second external electrode provided on the body. The body has: a first internal electrode layer containing Fe at a first concentration; a second internal electrode layer; a dielectric layer disposed between the first and second internal electrode layers in a first direction; and a first intermediate layer disposed between the first internal electrode layer and the dielectric layer, the first intermediate layer containing Fe at a second concentration. The first external electrode is electrically connected to the first internal electrode layer, and the second external electrode is electrically connected to the second internal electrode layer. The first external electrode includes a Ni plating layer. The first concentration is 0.01 at % or greater. The second concentration is equal to or greater than three times the first concentration while being 2 at % or less.