Capacitive Element With Composition-Graded Dielectric Films
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Solution Overview
Problem
Existing capacitive elements face challenges in achieving strong adhesion between electrodes and dielectric layers, leading to issues with film peeling and dielectric breakdown, particularly in high-withstand voltage applications.
Innovation Solution
A capacitive element design featuring a dielectric layer composed of laminated films with varying silicon or aluminum composition ratios, where the first and third films have higher silicon or aluminum content than the second film, enhancing adhesion and reducing dielectric breakdown by optimizing film thickness and composition ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple dielectric layer structure is used, then manufacturing is easier, but adhesion between electrodes and dielectric layer deteriorates
Solution Approach 1:
The dielectric layer is segmented into multiple sub-layers (first dielectric layer, second dielectric layer, third dielectric layer) with different composition ratios. This segmentation allows each layer to serve specific functions: the first layer provides good adhesion to the lower electrode, the second layer provides good adhesion to the upper electrode, and the third layer provides high withstand voltage capability, thereby resolving the contradiction between manufacturing simplicity and adhesion quality.
Solution Approach 2:
Different regions of the dielectric layer are assigned different composition ratios of silicon nitride and aluminum oxide. The first dielectric layer has a composition ratio optimized for adhesion to the lower electrode, the second layer has a composition ratio optimized for adhesion to the upper electrode, and the third layer has a composition ratio optimized for withstand voltage. This local quality differentiation resolves the contradiction by tailoring properties to specific functional requirements.
2Reliability
If higher silicon or aluminum content is used in dielectric films, then adhesion improves, but dielectric breakdown resistance may worsen
Solution Approach 1:
The patent applies local quality by assigning different composition ratios to different dielectric layers. The first dielectric layer has a higher silicon or aluminum content (70-100% by atomic ratio) to maximize adhesion to the lower electrode, while the third dielectric layer has a balanced composition to provide high withstand voltage capability. This localized optimization of composition ratios resolves the contradiction between adhesion improvement and dielectric breakdown resistance.
Solution Approach 2:
The dielectric layer uses a composite structure combining silicon nitride and aluminum oxide in different proportions across three sub-layers. This composite material approach allows the first layer to leverage the high adhesion properties of silicon-rich or aluminum-rich compositions, while the third layer uses a more balanced composition for electrical stability, thereby resolving the contradiction between adhesion and dielectric breakdown resistance.
3Device complexity
If a single-layer dielectric structure is used, then device complexity is reduced, but film peeling occurs
Solution Approach 1:
The dielectric layer is divided into three distinct sub-layers with different composition ratios, creating a segmented structure that prevents film peeling. The first layer with higher silicon or aluminum content bonds well to the lower electrode, the second layer provides an intermediate transition, and the third layer provides stable adhesion to the upper electrode. This segmentation eliminates the film peeling issue that occurs in single-layer structures while maintaining manageable device complexity.
Data Source
AI summary
A capacitive element includes: an upper electrode; a lower electrode; and a dielectric layer that is disposed between the upper electrode and the lower electrode, and includes a first film, a second film and a third film which are made of any one of silicon nitride and aluminum oxide and laminated from a side of the lower electrode in order, a composition ratio of any one of silicon and aluminum in each of the first film and the third film being larger than a corresponding composition ratio in the second film.