Capacitor Uneven Contact Surface Reduces ESR
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Solution Overview
Problem
Existing thin film capacitors face increased equivalent series resistance (ESR) and decreased Q value when reduced in size, due to increased contact resistance between terminal and base electrodes, and upper and terminal electrodes.
Innovation Solution
A capacitor design featuring a substrate with a dielectric layer and electrode layers, where at least one contact surface includes an uneven surface portion to increase contact area, reducing contact resistance and enhancing the Q value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the capacitor is reduced in size, then the compactness is improved, but the contact resistance increases
Solution Approach 1:
The invention transforms the contact surface from a two-dimensional flat plane to a three-dimensional uneven surface with protrusions and recesses. This dimensional change increases the effective contact area without increasing the planar footprint, thereby reducing contact resistance while maintaining compact capacitor size.
Solution Approach 2:
The uneven surface structure creates a porous-like morphology with multiple protrusions and recesses at the contact interface. This increases the surface area available for electrical contact between the terminal electrode and electrode layers, reducing contact resistance without requiring a larger overall capacitor volume.
2Reliability
If the contact surface area is increased to reduce contact resistance, then the contact resistance decreases, but the capacitor size increases
Solution Approach 1:
Instead of expanding the contact surface in the planar direction (which would increase capacitor footprint), the invention utilizes the vertical dimension by creating protrusions and recesses. This allows the contact area to be increased through surface topography changes rather than area expansion, maintaining compact dimensions.
Solution Approach 2:
The uneven surface structure concentrates the contact area enhancement at specific locations (protrusions and recesses) rather than uniformly expanding the entire contact surface. This localized quality change reduces contact resistance without requiring a proportional increase in overall capacitor size.
3Reliability
If the contact surface is made uneven to increase contact area, then the contact resistance decreases, but the manufacturing complexity increases
Solution Approach 1:
The invention controls the uneven surface structure by adjusting manufacturing parameters such as etching conditions, deposition thickness, and pattern dimensions. By optimizing these parameters, the protrusions and recesses are formed with controlled geometry, reducing manufacturing complexity while achieving the desired contact area increase.
Solution Approach 2:
The contact surface is segmented into multiple protrusions and recesses rather than forming a single complex irregular surface. This segmentation simplifies the manufacturing process by allowing standardized patterns to be repeated across the contact area, reducing overall device complexity while maintaining effective contact.
Data Source
AI summary
A capacitor having a substrate, a first electrode layer, a dielectric layer, a second electrode layer, and first and second outer electrodes. The substrate has a first main surface and a second main surface opposite to the first main surface. The first electrode layer is on the first main surface of the substrate. The dielectric layer is on at least part of the first electrode layer. The second electrode layer is on at least part of the dielectric layer. The first outer electrode is electrically connected to the first electrode layer and the second outer electrode is electrically connected to the second electrode layer. At least one of the first electrode layer and the first outer electrode and the second electrode layer and the second outer electrode are in contact with each other at a first contact surface. The first contact surface includes a first uneven surface portion.