FinFET SRAM and Logic Layout for Write Margin and Speed
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Solution Overview
Problem
Traditional FinFET fabrication methods face challenges in optimizing SRAM cell write margin and logic circuit speeds, particularly in embedded SRAM manufacturing, leading to suboptimal performance.
Innovation Solution
The implementation of FinFET logic circuits and SRAM cells with improved SRAM cell write margin without compromising logic circuit speeds, achieved through specific design optimizations such as using N-type and P-type FinFET transistors with silicon germanium and silicon fin materials, and strategic gate dielectric and gate electrode materials, along with isolation transistors for electrical isolation between adjacent cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional FinFET fabrication methods are used, then manufacturing process is simple, but SRAM cell write margin is insufficient
Solution Approach 1:
The patent applies different materials to different regions of the FinFET structure: silicon germanium for source/drain regions, silicon for channel fin, and different dielectric materials for gate dielectric layers. This local differentiation of material properties optimizes SRAM cell write margin by creating specific electrical characteristics in critical regions while maintaining overall device functionality.
Solution Approach 2:
The patent employs composite material structures combining silicon germanium and silicon in the FinFET, multiple dielectric layers including nitride and oxide, and various gate electrode materials. These composite structures enable simultaneous optimization of carrier mobility, threshold voltage control, and write margin without requiring complex fabrication processes.
2Speed
If traditional FinFET fabrication methods are used, then device structure is simple, but logic circuit speeds are compromised
Solution Approach 1:
The patent modifies key material parameters including using silicon germanium with specific bandgap properties for source/drain regions to enhance carrier mobility, selecting dielectric materials with appropriate permittivity values for gate dielectric layers, and optimizing gate electrode material composition. These parameter changes improve logic circuit speeds while maintaining manageable device structure complexity.
3Speed
If SRAM devices are designed for faster data access, then data access speed is improved, but area per stored bit increases
Solution Approach 1:
The patent implements local quality optimization within the SRAM cell structure by applying silicon germanium specifically to source/drain regions where carrier mobility enhancement is most needed for fast data access, while maintaining compact overall cell dimensions. This targeted approach improves data access speed without proportionally increasing area per stored bit.
Data Source
AI summary
An integrated circuit (IC) structure includes a substrate and a fin structure. The substrate includes a first cell region and a second cell region abutting the first cell region. The fin structure includes a first plan-view profile within the first cell region and a second plan-view profile within the second cell region. The first plan-view profile includes a first sidewall and a second sidewall opposing the first sidewall. The second plan-view profile includes a third sidewall and a fourth sidewall opposing the third sidewall. A width between the first sidewall and the second sidewall is greater than a width between the third sidewall and the fourth sidewall.