Monolithic Ceramic Capacitor C-Axis Orientation
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Solution Overview
Problem
Monolithic ceramic capacitors face challenges in achieving smaller sizes and larger capacities while maintaining reliability, as reducing ceramic layer thickness to increase capacity prolongs manufacturing time and increases costs, and thin layers are prone to dielectric breakdown.
Innovation Solution
A monolithic ceramic capacitor design with a ceramic sintered body featuring a high proportion of opposed electrode regions, where the c-axis peak intensity to a-axis peak intensity ratio is 2 or more, allowing for increased polarizability without excessively thinning the ceramic layer, and incorporating side gap portions to reduce compressive stress and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the ceramic layer is reduced to increase capacity, then the capacity of the capacitor increases, but the manufacturing time is prolonged and manufacturing cost increases
Solution Approach 1:
The invention changes the crystallographic orientation parameters of the ceramic layer by controlling the sintering process to achieve a c-axis peak intensity to a-axis peak intensity ratio of 1.5 or more. This parameter change increases polarizability and allows for larger capacity without requiring excessive thinning of the ceramic layer, thereby avoiding prolonged manufacturing time and increased costs
2Quantity of substance
If the thickness of the ceramic layer is reduced to increase capacity, then the capacity of the capacitor increases, but dielectric breakdown is apt to occur and reliability is degraded
Solution Approach 1:
The invention changes the crystallographic orientation parameters to achieve high c-axis alignment (Ic/Ia ≥ 1.5), which increases polarizability. This allows the ceramic layer to maintain adequate thickness for reliability while achieving larger capacity, preventing dielectric breakdown
Solution Approach 2:
The invention creates different structural qualities in different regions of the capacitor. The opposed portions have high c-axis alignment for maximum polarizability and capacity, while the side gap portions provide stress relief. This local differentiation allows the ceramic layer to maintain sufficient thickness for reliability in critical areas while achieving large overall capacity
3Quantity of substance
If the ceramic layer is thinned to achieve smaller size, then the capacity increases, but the manufacturing cost increases
Solution Approach 1:
The invention changes the sintering parameters and crystallographic orientation control to achieve high c-axis alignment. This allows the ceramic layer to maintain adequate thickness without requiring excessive pulverizing time, thereby reducing manufacturing cost while still achieving large capacity
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 design enables a larger capacity with high reliability by optimizing the ceramic layer's polarizability and reducing the risk of dielectric breakdown, thus addressing the limitations of existing capacitors.
Implementation Method 1
the polarizability of the ceramic layer in the first portion can be increased. As a result, a larger capacity can be obtained without excessively reducing the thickness of the ceramic layer
Implementation Method 2
A ratio (Ic/Ia) of c-axis peak intensity (Ic) to a-axis peak intensity (Ia) measured with an XRD analysis of the one of the ceramic layers is about 2 or more
Data Source
AI summary
A monolithic ceramic capacitor having a large capacity and high reliability includes a ceramic sintered body including a plurality of stacked ceramic layers, and first and second inner electrodes and alternately disposed inside the ceramic sintered body to be opposed to each other in a stacking direction of the ceramic layers with one of the ceramic layers being interposed between the adjacent first and second inner electrodes. The ceramic sintered body includes a first portion in which the first and second inner electrodes are opposed to each other, and a second portion positioned outside the first portion. A ratio (Ic/Ia) of c-axis peak intensity (Ic) to a-axis peak intensity (Ia) measured with an XRD analysis of the one of the ceramic layers is about 2 or more.