Polycrystalline Metal Capacitor With Electrophoretic Insulator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thin-film capacitors face issues with increased leakage current and short-circuit failures due to grain boundaries in the polycrystalline metal electrodes, even without defects in the dielectric layer, and existing solutions degrade capacitor characteristics when attempting to address these issues.
Innovation Solution
A capacitor design featuring a polycrystalline metal foil lower electrode, a dielectric layer, and an upper electrode layer, with a resin insulator selectively deposited by electrophoresis to cover grain boundaries and defects, enhancing electrical resistance and preventing leakage current and short-circuit failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the dielectric layer is reduced to achieve reductions in dimensions and height, then the capacitor size is reduced, but leakage current increases and withstand voltage decreases
Solution Approach 1:
The invention divides the electrode structure into multiple segments: a lower electrode layer, an insulator layer formed by oxidizing the electrode material, and an upper electrode layer. This segmentation creates multiple barrier layers that collectively prevent leakage current while maintaining a thin overall dielectric structure.
Solution Approach 2:
The invention uses composite material structure consisting of the dielectric layer combined with an insulator layer formed from oxidized electrode material. This composite structure provides both the dielectric function and the leakage prevention function, solving the contradiction between thin dielectric layer and low leakage current.
2Reliability
If an insulator is provided on or below the dielectric layer to prevent short-circuit failure and increase in leakage current, then reliability is improved, but capacitor characteristics are degraded if the insulator is too large
Solution Approach 1:
The insulator layer is formed locally at the interface between the lower electrode layer and the dielectric layer, specifically where leakage current tends to occur. This localized approach prevents short-circuit failure without unnecessarily reducing the effective capacitance area, thus maintaining capacitor characteristics.
Solution Approach 2:
The insulator layer acts as an intermediary between the lower electrode layer and the dielectric layer. It provides electrical insulation and prevents direct contact that could cause short-circuit, while its controlled thickness ensures it does not significantly reduce the capacitance of the overall structure.
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 effectively prevents leakage current and short-circuit failures while maintaining capacitor performance and reducing the risk of degradation, allowing for reliable high-capacity capacitors with improved reliability and reduced leakage current.
Implementation Method 1
a resin insulator that is disposed between the top surface of the dielectric layer and the bottom surface of the upper electrode layer and that is present only in part of a region in which the top surface of the dielectric layer and the bottom surface of the upper electrode layer face each other
Data Source
AI summary
A capacitor comprises: a lower electrode formed of a foil made of a polycrystalline metal; an upper conductor layer; and a dielectric layer disposed between the lower electrode and the upper electrode layer. Grain boundaries of the polycrystalline metal appear at the top surface of the lower electrode. The capacitor further comprises an insulator that is disposed between the top surface of the dielectric layer and the bottom surface of the upper electrode layer and that is present only in part of a region in which the top surface of the dielectric layer and the bottom surface of the upper electrode layer face each other. The insulator is disposed to cover at least part of the grain boundaries appearing at the top surface of the lower electrode when seen from above the top surface of the dielectric layer. The insulator is formed by electrophoresis.