Stacked Gate Electrode Structure for Parasitic Capacitance Reduction
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Solution Overview
Problem
Highly integrated semiconductor devices face challenges in reducing short channel effects, and existing technologies have limitations in optimizing gate electrode structures for improved performance and manufacturing efficiency.
Innovation Solution
A semiconductor device design featuring a first gate electrode crossing an active region with a second gate electrode on top, where the second gate electrode has a narrower width and potentially different materials, along with spacers and a gate dielectric layer, to enhance performance and manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single wide gate electrode is used, then the gate control over the channel is strong, but the parasitic capacitance increases and short channel effects worsen
Solution Approach 1:
The gate electrode is divided into two separate gates (first gate electrode and second gate electrode) positioned at different heights. The first gate electrode has a wider width for strong channel control, while the second gate electrode has a narrower width to reduce parasitic capacitance. This segmentation allows each gate to perform specialized functions, resolving the contradiction between control strength and capacitance reduction.
Solution Approach 2:
The patent introduces a vertical dimension by stacking the first and second gate electrodes at different heights above the substrate. This three-dimensional gate structure allows the wider first gate to provide strong control while the narrower second gate reduces capacitance, effectively resolving the contradiction by utilizing spatial dimensionality rather than relying solely on planar dimensions.
2Object-affected harmful factors
If multiple gate electrodes are introduced, then parasitic capacitance is reduced, but device complexity increases
Solution Approach 1:
The first and second gate electrodes are merged into a unified gate structure that works together to control the channel. Despite being at different heights and having different widths, they function as an integrated system, reducing the effective complexity compared to completely separate gate structures. The merged approach maintains manufacturing feasibility while achieving capacitance reduction.
3Reliability
If different materials are used for first and second gate electrodes, then performance is optimized, but manufacturing precision requirements increase
Solution Approach 1:
Different materials are used for the first and second gate electrodes based on their specific functional requirements. The first gate electrode uses a material optimized for strong channel control, while the second gate electrode uses a material optimized for low parasitic capacitance. This local quality differentiation allows performance optimization while maintaining manufacturing precision through targeted material selection at each gate location.
Data Source
AI summary
Provided is a semiconductor device having first and second gate electrodes. The semiconductor device includes a substrate, an active region extending in a first direction on the substrate, a first gate electrode crossing the active region and extending in a second direction, and a second gate electrode extending in the second direction on the first gate electrode, wherein the first gate electrode has a first width in the first direction, and wherein the second gate electrode has a second width in the first direction, the second width being less than the first width.