Skew Cell Layout With Cut Poly Gates for Low-Leakage Sizing
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Solution Overview
Problem
Standard cell architectures face challenges in incorporating L-shaped diffusion regions due to increased costs and leakage effects, limiting the ability to provide skewed sizing for PMOS and NMOS devices, which complicates fabrication and reduces efficiency in logic circuits.
Innovation Solution
The implementation of a novel skew cell layout architecture that allows for double-height or quad-height skew cells by positioning P-type and N-type diffusion regions with cut poly-gate rails to create open spaces, enabling rise and fall skewed designs that improve timing and reduce leakage, suitable for various circuit applications including IoT and automotive systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If L-shaped diffusion regions are used for skewed sizing, then PMOS and NMOS device sizing flexibility is improved, but fabrication cost increases due to additional mask layers
Solution Approach 1:
The cell is divided into two separate height sections: a first height section containing PMOS devices and a second height section containing NMOS devices. This segmentation allows each section to be independently sized and optimized, achieving skewed sizing without requiring L-shaped diffusion regions that would add fabrication complexity
Solution Approach 2:
The patent transitions from planar 2D layout constraints to 3D vertical stacking by utilizing different cell heights for PMOS and NMOS sections. This dimensional change enables skewed sizing while maintaining standard fabrication processes, as the height differentiation is achieved through vertical stacking rather than complex lateral diffusion patterns
2Adaptability or versatility
If L-shaped diffusion regions are used for skewed sizing, then device sizing flexibility is improved, but leakage effects increase
Solution Approach 1:
By segmenting the cell into separate PMOS and NMOS height sections with distinct active regions, the patent eliminates the need for L-shaped diffusion connections. Each transistor type has its own rectangular active region, preventing the leakage issues associated with L-shaped diffusions while maintaining skewed sizing capability through height differentiation
Solution Approach 2:
The patent uses separate, complete active regions for PMOS and NMOS devices rather than sharing or connecting them through L-shaped structures. Each section is a self-contained copy of a standard cell section, eliminating the harmful L-shaped diffusion geometry that causes leakage while preserving the ability to size devices differently
3Productivity
If standard cell architecture is used, then fabrication efficiency is maintained, but skewed sizing for logic circuits is limited
Solution Approach 1:
The patent introduces dynamic height allocation where the first height section and second height section can be independently configured to match the specific sizing requirements of PMOS and NMOS logic circuits. This dynamic adaptability allows standard fabrication processes to produce customized skewed cells without requiring new fabrication techniques, maintaining efficiency while enhancing versatility
Solution Approach 2:
The dual-height cell structure serves multiple functions: it enables skewed sizing for different logic circuits, maintains compatibility with standard fabrication processes, and allows independent optimization of PMOS and NMOS sections. This multi-functionality achieves adaptability without sacrificing fabrication efficiency
Data Source
AI summary
Various implementations described herein are directed to a device having a skew cell architecture with multiple diffusion regions including P-type diffusion regions disposed between N-type diffusion regions. The device may have power rails including a voltage supply rail disposed between ground rails. The device may have poly-gate rails disposed between the ground rails. The poly-gate rails may be cut to provide an open space between at least one N-type diffusion region and at least one P-type diffusion region.