MLCC Dielectric Grain Orientation for Higher Capacitance Density
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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, oriented in a specific crystallographic plane, enhancing the dielectric constant and enabling a further reduction in size and increase in capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the dielectric ceramic layers are formed as thin layers to reduce capacitor size, then the capacitance density increases, but the manufacturing precision and reliability become more difficult to maintain
Solution Approach 1:
The patent changes the crystallographic orientation parameter of the dielectric ceramic from random or conventional orientations to specifically oriented {100} grains. This parameter change enables the use of thinner dielectric layers while maintaining or improving dielectric constant, thus achieving reduced capacitor size without sacrificing manufacturing precision or reliability.
Solution Approach 2:
The patent employs a composite microstructure within the dielectric ceramic layers, combining {100} oriented grains with specific grain size distributions and phase compositions. This composite approach allows thin dielectric layers to achieve high dielectric constants while maintaining manufacturing feasibility and device reliability.
2Reliability
If the dielectric constant is increased by controlling composition and crystal grain diameter, then the capacitance increases, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent simplifies the dielectric ceramic structure by focusing on a single critical parameter: the crystallographic orientation of grains. By specifying {100} grain orientation as the primary control parameter, the patent avoids the complexity of simultaneously optimizing multiple composition and microstructure parameters, thus achieving high capacitance with reduced device complexity.
3Reliability
If the number of dielectric ceramic layers is increased to increase capacitance, then the electrostatic capacitance increases, but the manufacturing precision and assembly complexity increase
Solution Approach 1:
By changing the dielectric constant through crystallographic orientation control rather than increasing layer count, the patent reduces the number of layers required to achieve target capacitance values. This parameter change directly reduces stacking precision requirements and assembly complexity while maintaining or improving 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 {100} grain orientation in the dielectric ceramic layers increases the dielectric constant, allowing for a compact design with enhanced capacitance and improved reliability and high-temperature operating life.
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 Er
Implementation Method 2
the crystal grains include a large percentage of a high-ferroelectricity crystal phase in the inner region (core portion) because they include little rare earth element in this region, and this allows for strengthening the dielectric constant
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.