Multilayer Ceramic Capacitor {100} Grain Control for Compact Capacitance
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Solution Overview
Problem
Existing multilayer ceramic capacitors face limitations in reducing size and increasing capacitance despite efforts to control dielectric constant through composition and crystal grain diameter in dielectric ceramic layers.
Innovation Solution
The dielectric ceramic layers in multilayer ceramic capacitors are composed of perovskite oxide with a high percentage of {100} grains, as determined by scanning transmission electron microscopy, to enhance dielectric constant and reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of dielectric ceramic layers is reduced to increase capacitance, then the capacitance increases, but the manufacturing precision and reliability deteriorate
Solution Approach 1:
The patent changes the crystallographic orientation parameter of the dielectric ceramic layers, specifically increasing the percentage of <100>-oriented grains from conventional levels to 4% or more. This parameter change in crystal structure allows the capacitor to achieve high capacitance with thicker dielectric layers, thereby resolving the contradiction between reduced thickness for higher capacitance and the manufacturing precision required to maintain reliability.
2Quantity of substance
If the area of inner electrode layers is increased to increase capacitance, then the capacitance increases, but the device size increases
Solution Approach 1:
The patent utilizes parameter changes in the dielectric constant through crystallographic orientation control. By achieving 4% or more <100>-oriented grains, the dielectric constant is significantly enhanced, allowing the capacitor to achieve high capacitance values with smaller electrode areas, thus resolving the contradiction between increased capacitance and increased device area.
3Quantity of substance
If the dielectric constant is increased through composition control to increase capacitance, then the capacitance increases, but the manufacturing complexity increases
Solution Approach 1:
The patent simplifies the approach to increasing dielectric constant by changing the crystallographic orientation parameter rather than complex composition control. By controlling the grain orientation to achieve 4% or more <100>-oriented grains through sintering condition optimization, the patent achieves high dielectric constant and capacitance without the complexity of multi-element composition control, resolving the contradiction between increased dielectric constant and manufacturing complexity.
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 configuration increases the dielectric constant and capacitance of multilayer ceramic capacitors, improving reliability and high-temperature operating life while maintaining compact dimensions.
Implementation Method 1
the relative permittivity of the dielectric ceramic layers is denoted by εr, the electrostatic capacitance C of the multilayer ceramic capacitor is proportional to the relative permittivity εr
Data Source
AI summary
A multilayer ceramic capacitor includes a body including dielectric ceramic layers and inner electrode layers. The dielectric ceramic layers include crystal grains including a perovskite oxide including at least one A-site element and at least one B-site element. When a cross-section of the dielectric ceramic layers is observed using a scanning transmission electron microscope, the dielectric ceramic layers include grains, on which a plane of a perovskite structure is observed, as crystal grains. In the cross-section, a percentage by number of the grains in the crystal grains is about 4% or more.