Multilayer Ceramic Capacitor Polarity-Specific Electrodes for Thin Dielectrics
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Solution Overview
Problem
Multilayer ceramic capacitors with Ni as a main component in their inner electrodes face reliability issues due to increased electric field intensity from thinner dielectric layers, which is insufficient for recent demands in miniaturization and higher capacitance.
Innovation Solution
The use of alternating first and second inner electrodes with distinct metal compositions, including Ni and Sn for the first electrodes and Ni with additional elements like Au, Pt, Ir, Pd, Os, Ag, Rh, and Cu for the second electrodes, where the second electrodes have higher standard electrode potentials to reduce oxygen ion segregation and insulation degradation, allowing for thinner electrodes and increased capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dielectric layers are made thinner to achieve miniaturization and higher capacitance, then the capacitance and miniaturization requirements are met, but the electric field intensity increases and reliability during voltage application deteriorates
Solution Approach 1:
The patent applies different metal compositions to different inner electrodes based on their functional roles. First inner electrodes (positive polarity) use a first metal composition while second inner electrodes (negative polarity) use a second metal composition with different properties. This local differentiation allows optimization of each electrode's performance characteristics to address the reliability issue caused by high electric field intensity in thin dielectric layers.
Solution Approach 2:
The patent employs composite metal compositions for the inner electrodes, where the first metal composition and second metal composition have distinct elemental compositions. The second metal composition specifically includes elements with higher standard electrode potentials than the first metal composition, creating a composite structure that reduces oxygen ion segregation and prevents insulation degradation, thereby improving reliability under high electric field conditions.
2Temperature
If inner electrodes include Ni as a main component, then the melting point is increased compared to Cu, but the reliability during voltage application remains insufficient for miniaturization demands
Solution Approach 1:
The patent differentiates the metal composition between first and second inner electrodes. While both maintain Ni as a main component for high melting point, the second inner electrodes incorporate additional elements with higher standard electrode potentials to specifically address the reliability issue during voltage application, creating local compositional optimization.
Solution Approach 2:
The patent creates composite metal compositions where Ni serves as the base metal for high melting point, and additional elements (such as Au, Pt, Ir, Pd, Os, Ag, Rh, or Cu) are incorporated into the second metal composition. This composite approach maintains the thermal stability provided by Ni while adding elements that reduce oxygen ion segregation and improve electrical reliability under voltage stress.
3Quantity of substance
If the number of layers is increased to maintain external dimensions, then the capacitance increases, but the dielectric layer thickness must be reduced further which worsens the electric field intensity and reliability
Solution Approach 1:
The patent applies differentiated metal compositions to first and second inner electrodes, allowing each electrode to be optimized for its specific functional role. This enables the use of thinner dielectric layers with higher layer counts while maintaining reliability, as the local compositional optimization compensates for the increased electric field intensity in thinner layers.
Solution Approach 2:
The composite metal compositions, particularly the second metal composition with elements of higher standard electrode potential, provide enhanced resistance to insulation degradation. This allows the capacitor structure to accommodate more layers with thinner dielectric layers while maintaining external dimensions and improving capacitance without sacrificing reliability.
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
This approach enhances the reliability and capacitance of multilayer ceramic capacitors by preventing insulation degradation and allowing for thinner electrodes with higher melting points, maintaining external dimensions while increasing electrostatic capacitance.
Implementation Method 1
the second electrodes have higher standard electrode potentials to reduce oxygen ion segregation and insulation degradation
Data Source
AI summary
In a multilayer ceramic capacitor including first and second inner electrodes alternately arranged with respect to a stacking direction of a multilayer body, a polarity based on a direction of voltage applied between a first outer electrode and a second outer electrode is determined such that the first inner electrodes function as positive electrodes and the second inner electrodes function as negative electrodes. The first inner electrodes have a first metal composition including Ni and Sn, and the second inner electrodes have a second metal composition including Ni. The second metal composition of the second inner electrodes may consist of Ni, or may include Ni as a main component and at least one metal element selected from Au, Pt, Ir, Pd, Os, Ag, Rh, Ru, and Cu, which have standard electrode potentials higher than that of Ni.