MLCC Dielectric Layer Composition for Thin-Layer Insulation Life
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Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in maintaining high reliability and insulation resistance with reduced layer thickness, especially under high temperature and humidity conditions, as conventional methods using rare earth elements and magnesium in dielectric layers still have room for improvement.
Innovation Solution
Incorporating a rare earth element high-concentration region in dielectric ceramic layers with a molar ratio of Re/Ti ranging from 0.04 to 0.30 and an area proportion of 50% or more, along with a controlled distribution of rare earth element low-concentration regions, enhances the reliability and permittivity of multilayer ceramic capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of dielectric layers is reduced to make compact capacitors, then the size of the capacitor is reduced, but the insulation resistance life between internal electrode layers is shortened
Solution Approach 1:
The patent applies local quality by creating a dual-region structure within the dielectric layer: a rare earth element high-concentration region and a low-concentration region. This non-uniform distribution allows different regions to perform different functions - the high-concentration region provides strong oxygen vacancy pinning for insulation stability, while the low-concentration region maintains permittivity. This resolves the contradiction by enabling thin dielectric layers to maintain both compact size and long insulation resistance life through localized functional zones.
2Reliability
If rare earth elements are added to dielectric layers to extend insulation resistance life, then reliability is improved, but the complexity of material composition increases
Solution Approach 1:
The patent reduces material composition complexity by applying local quality - concentrating rare earth elements only in specific high-concentration regions rather than uniformly distributing them throughout the entire dielectric layer. This localized approach means less total rare earth content is needed to achieve the same insulation improvement, simplifying the overall material system while maintaining high reliability.
Solution Approach 2:
The patent uses composite materials by combining rare earth element oxides with barium titanate-based dielectric materials in a structured dual-concentration configuration. This composite structure leverages the high oxygen vacancy pinning capability of rare earth elements in specific regions while maintaining the high permittivity of the barium titanate matrix, achieving improved insulation resistance life without requiring complete reformulation of the base dielectric material system.
3Reliability
If uniform rare earth element distribution is used in dielectric layers, then insulation resistance is improved, but permittivity and voltage dependency characteristics deteriorate
Solution Approach 1:
The patent resolves this contradiction by applying local quality with a dual-concentration structure - rare earth element high-concentration regions provide strong oxygen vacancy pinning for excellent insulation resistance, while rare earth element low-concentration regions maintain the dielectric properties and permittivity. This spatially differentiated composition allows each region to optimize for its specific function, achieving both high insulation resistance and controlled permittivity simultaneously.
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 significantly improves the reliability and permittivity of multilayer ceramic capacitors by preventing oxygen vacancy migration and reducing voltage dependency, thereby extending insulation resistance life and maintaining high capacitance.
Implementation Method 1
a rare earth element high-concentration region in an area proportion of about 50% or more, the rare earth element high-concentration region referring to an area where a molar ratio (Re/Ti ratio) of a rare earth element (Re) to titanium (Ti) is about 0.04 or more and about 0.30 or less
Data Source
AI summary
A multilayer ceramic capacitor includes a base body including dielectric ceramic layers and internal electrode layers stacked in a thickness direction, and a pair of external electrodes on first and second end surfaces and electrically connected to the internal electrode layers. The dielectric ceramic layers include, as a main component, crystal grains including a perovskite complex oxide including barium and titanium, and a rare earth element, and include, in a cross section including the thickness direction, a rare earth element high-concentration region in an area proportion of about 50% or more, the rare earth element high-concentration region including the rare earth element in a molar ratio of the rare earth element to titanium of about 0.04 or more and about 0.30 or less.