Capacitor Dielectric Layer with Porous Aluminum Oxide
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Solution Overview
Problem
Solid aluminum capacitors have low operating voltage due to the limited thickness of the dielectric layer on the bottom surface, which is difficult to increase, and the brittle nature of the ceramic alumina dielectric layer, making them prone to breakage and costly to process.
Innovation Solution
A capacitor design featuring a dielectric layer with a dense layer and a porous layer, where the porous layer has smaller pores and a thicker bottom, formed through a two-stage anodizing process, reducing brittleness and increasing operating voltage without the need for pre- and post-processing of the anodizing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the dielectric layer thickness is increased to raise operating voltage, then the operating voltage is improved, but the dielectric layer becomes more brittle and prone to breakage
Solution Approach 1:
The dielectric layer is designed with non-uniform thickness: a thicker bottom portion (first thickness) that provides mechanical strength and voltage resistance, and a thinner top portion (second thickness) that reduces brittleness. This local variation in thickness allows the capacitor to achieve higher operating voltage while maintaining structural integrity and reducing breakage risk.
2Temperature
If a thick dielectric layer is formed to increase operating voltage, then the operating voltage is improved, but the processing cost increases due to required pre- and post-processing steps
Solution Approach 1:
The method forms the dielectric layer with the desired thick bottom portion and thinner top portion in a single continuous anodizing process without requiring separate pre-processing or post-processing steps. The anodizing conditions (voltage, time, electrolyte composition) are controlled to automatically produce the non-uniform thickness profile, eliminating additional processing steps and reducing manufacturing cost.
3Temperature
If the dielectric layer is made thicker to increase operating voltage, then the operating voltage is improved, but the capacitor structure becomes more complex
Solution Approach 1:
The dielectric layer exhibits local quality variation in thickness without requiring additional structural components. The bottom portion has greater thickness for electrical performance, while the top portion has lesser thickness for mechanical flexibility. This single-layer non-uniform structure achieves the desired functionality without increasing overall device complexity.
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 capacitor achieves a higher operating voltage and reduced brittleness, enhancing its resilience and electrostatic capacity while simplifying the manufacturing process by forming a thicker, more stable dielectric layer without additional processing steps.
Implementation Method 1
an aluminum film is anodized to form a first oxide film having multiple pores in its surface (first anodizing process), the aluminum film having the first oxide film is again anodized to form a first dielectric layer in which a part of each pore of the first oxide film is filled with aluminum oxide (second anodizing process)
Data Source
AI summary
Provided is a capacitor, which includes a first electrode including aluminum, a second electrode facing the first electrode, and a first dielectric layer interposed between the first electrode and the second electrode, including aluminum oxide, and having multiple pores defined in a surface of the first dielectric layer in contact with the second electrode.