Modulation Unit Layout With Holed Metal Layer for Stable Threshold Voltage
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Solution Overview
Problem
During the manufacture of electronic devices, ions in the metal layer on the substrate diffuse to the upper element area, causing degradation of element characteristics, and the grain roughness of the semiconductor layer is increased due to the underlying metal layer, leading to reduced carrier mobility and threshold voltage shift.
Innovation Solution
A modulation device is designed with a substrate, a metal layer having at least one hole, and a driving element positioned within the hole, where the metal layer's thickness varies to minimize ion diffusion and roughness impact, and a modulation unit is electrically connected to the driving element to control electromagnetic waves and improve device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous metal layer is used on the substrate, then electrical connectivity and shielding are improved, but ion diffusion to the upper element area increases and grain roughness of the semiconductor layer increases
Solution Approach 1:
The metal layer is segmented by introducing holes (via holes or contact holes) that penetrate through the metal layer, dividing the continuous metal layer into isolated regions. This segmentation prevents ion diffusion from reaching the upper element area while maintaining electrical connectivity through the holes, and reduces the grain roughness impact on the semiconductor layer by limiting the metal layer's direct contact area.
2Reliability
If a continuous metal layer is used on the substrate, then electrical connectivity is improved, but threshold voltage shift occurs due to electrical coupling with the underlying metal layer
Solution Approach 1:
The metal layer is segmented by introducing holes that penetrate through it, creating isolated metal regions. This segmentation reduces the electrical coupling between the underlying metal layer and the upper element area, thereby preventing threshold voltage shift while maintaining necessary electrical connectivity through the holes.
Solution Approach 2:
The holes in the metal layer act as intermediaries that control and limit the electrical coupling between the underlying metal layer and the upper element area. By strategically positioning and sizing these holes, the patent achieves the desired electrical connectivity while preventing excessive coupling that would cause threshold voltage shift.
3Reliability
If the metal layer thickness is increased, then shielding and electrical connectivity are improved, but ion diffusion and roughness impact on the semiconductor layer increase
Solution Approach 1:
The metal layer is segmented by introducing holes that penetrate through it, creating isolated metal regions. This segmentation prevents ion diffusion from reaching the upper element area regardless of the metal layer thickness, while maintaining shielding effectiveness through the continuous metal regions between the holes.
Solution Approach 2:
The metal layer is designed with different properties in different regions: thicker regions provide shielding and electrical connectivity, while the holes (local regions) prevent ion diffusion and reduce roughness impact. This local quality variation allows the patent to achieve both shielding effectiveness and reduced harmful effects.
Data Source
AI summary
A modulation device includes a substrate, a metal layer, at least one driving element, and a modulation unit. The metal layer is disposed on the substrate and has at least one hole. The at least one driving element is disposed on the substrate and overlapped with the at least one hole. The modulation unit is electrically connected to the at least one driving element.