Multilayer Ceramic Capacitor Grain Boundary Stabilization
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Solution Overview
Problem
Multilayer ceramic capacitors with BaTiO3 dielectric layers face reliability issues due to oxygen vacancy migration under DC voltage, particularly at grain boundaries, which existing technologies do not adequately address.
Innovation Solution
Incorporating a rare earth element like Dy into the dielectric layer to create Ba vacancies, which stabilize oxygen vacancies at grain boundaries, thereby suppressing their migration and enhancing the capacitor's reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC voltage is applied to the dielectric layer, then the capacitor operates normally, but oxygen vacancies migrate which degrades reliability
Solution Approach 1:
The patent introduces a concentrated region of first element (such as rare earth element) at the grain boundary before DC voltage is applied. This preliminary structural arrangement creates stable positions for oxygen vacancies at the grain boundary, preventing their migration when voltage is subsequently applied, thereby maintaining compositional stability and reliability.
Solution Approach 2:
The patent creates a localized concentrated region of first element specifically at the grain boundary interface, rather than uniformly distributing it throughout the dielectric layer. This local modification targets the specific problem area (grain boundary where oxygen vacancies migrate) without altering the bulk properties of the dielectric material.
2Reliability
If Ba2+ is substituted with RE3+ to suppress oxygen vacancy migration, then reliability improves, but the crystal lattice structure changes
Solution Approach 1:
The substitution of Ba2+ with RE3+ is localized to the concentrated region at the grain boundary, rather than being uniformly distributed throughout the entire dielectric layer. This localized substitution minimizes the overall structural change while achieving the desired effect of stabilizing oxygen vacancies at the critical grain boundary region.
Solution Approach 2:
The patent carefully controls the concentration and distribution parameters of the first element (RE3+) at the grain boundary, optimizing the substitution level to achieve sufficient oxygen vacancy stabilization without causing excessive lattice distortion or other adverse structural changes that would compromise dielectric performance.
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 approach effectively improves the reliability of multilayer ceramic capacitors by reducing oxygen vacancy migration and maintaining high insulating resistance, as demonstrated by increased mean time to failure and dielectric constant values under high-temperature testing.
Implementation Method 1
Ba2+ which is a positive divalent ion of Ba in a crystal lattice of BaTiO3 is allegedly effectively substituted with RE3+ which is a positive trivalent ion of a rare earth element RE
Implementation Method 2
positive charges become excessive. Therefore, Ba vacancy regarded as being relatively negatively divalently charged is produced to satisfy an electrically neutral condition
Implementation Method 3
This Ba vacancy and oxygen vacancy that can be regarded as being relatively positively divalently charged form a stable defect pair
Implementation Method 4
Since Ba vacancy is less likely to migrate in spite of application of a DC voltage, migration of the oxygen vacancy is suppressed by the oxygen vacancy being retained by the Ba vacancy
Data Source
AI summary
A multilayer ceramic electronic component that includes a multilayer body including a dielectric layer and an internal electrode layer that are layered. The dielectric layer contains a plurality of dielectric particles containing Ba and Ti. The plurality of dielectric particles contain a first concentrated region containing a first element and located at an interface with an adjacent dielectric particle of the plurality of dielectric particles, and a second concentrated region containing the first element and present at an interface within 50 nm from the first concentrated region.