Multilayer Capacitor Dielectric Grain Structure for Thin-Layer Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to reduce the size and increase the capacitance of multilayer capacitors while maintaining reliability, as thinning the dielectric and internal electrode layers leads to increased voltage and reliability issues.
Innovation Solution
A multilayer capacitor design featuring a dielectric layer with grains having a core-shell structure and a pore in the core, where 20% to 40% of the grains have two or less pores, and an average grain size of 200 nm or less, along with an average dielectric layer thickness of 0.7 μm or less, to achieve high dielectric constants and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the dielectric layer thickness is reduced to decrease capacitor size, then the capacitance density increases, but the reliability deteriorates due to increased voltage stress
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the grain core contains pores and the shell is dense, with different compositions (core: BaTiO3-based dielectric, shell: barium titanate-based dielectric with rare earth elements). This local differentiation allows the thin dielectric layer to maintain high reliability through the protective shell while achieving high capacitance density through the porous core, resolving the contradiction between reduced size and maintained reliability.
2Quantity of substance
If the dielectric layer thickness is reduced to increase capacitance density, then the capacitance per unit volume increases, but the voltage stress increases causing reliability issues
Solution Approach 1:
The patent employs composite materials by combining two different dielectric materials in a core-shell structure: the core uses BaTiO3-based dielectric with pores for high capacitance, while the shell uses barium titanate-based dielectric doped with rare earth elements (lanthanum, cerium, neodymium, or praseodymium) for enhanced electrical stability and reliability. This composite approach enables high capacitance density while maintaining reliability under voltage stress.
3Force
If the grain size is reduced to increase dielectric constant, then the dielectric properties improve, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies segmentation by dividing each grain into two distinct regions: a porous core and a dense shell. This segmentation allows the overall grain structure to achieve high dielectric constant through the porous core while the shell provides a well-defined boundary that simplifies manufacturing control. The core-shell segmentation effectively decouples the conflicting requirements of high dielectric constant and manufacturing precision.
Data Source
AI summary
A multilayer capacitor includes a body including a dielectric layer and internal electrodes; and an external electrode disposed on the body to be connected to the internal electrode, wherein the dielectric layer includes a plurality of grains having a core-shell structure having a pore in a core, and the dielectric layer includes 20% to 40% of grains having two or less pores, among the plurality of grains.