Asymmetric FinFET SRAM Cell for Low Voltage Operation
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Solution Overview
Problem
Conventional SRAMs face challenges in reducing minimum operating voltage while integrating more data storage cells and minimizing power consumption, especially in portable electronics and high-speed computation applications.
Innovation Solution
The design incorporates fin field-effect transistors (FinFETs) with an asymmetric layout of gate electrode layers and interconnection structures in the 8T SRAM cell, allowing for efficient electrical connections and reduced power supply voltage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional transistors are used in SRAM cells, then the transistor size and power consumption are larger, but replacing them with FinFETs enables smaller size and lower power consumption
Solution Approach 1:
The patent changes the physical parameters of the transistor by transitioning from planar transistors to FinFETs, which have a three-dimensional channel structure. This parameter change enables smaller device footprint and lower power consumption while maintaining electrical performance, directly resolving the contradiction between power efficiency and device complexity
Solution Approach 2:
The patent introduces a vertical dimension by using FinFETs with channels extending in the vertical direction rather than only in the planar direction. This dimensional change allows for better gate control and reduced leakage current, achieving lower power consumption without proportionally increasing device complexity
2Quantity of substance
If more data storage cells are integrated into a single SRAM chip, then storage capacity increases, but minimum operating voltage tends to increase
Solution Approach 1:
The patent employs asymmetric layout design in the SRAM cell structure, where the pull-up and pull-down networks are arranged asymmetrically with respect to the bit lines. This asymmetry optimizes the voltage swing and signal integrity, enabling reliable operation at lower voltages even as the number of integrated cells increases
Solution Approach 2:
The patent segments the SRAM cell into distinct functional blocks with optimized interconnection paths, separating the read and write paths to minimize interference. This segmentation allows for better voltage management and signal isolation, maintaining reliable operation at reduced minimum operating voltages across large arrays
3Reliability
If FinFETs with asymmetric layout are used, then power supply voltage requirements are reduced, but layout complexity increases
Solution Approach 1:
The patent designs a universal asymmetric FinFET layout that serves multiple functions: it provides optimized voltage swing for low-voltage operation, ensures proper signal isolation, and maintains compatibility with standard manufacturing processes. This multi-functional design reduces layout complexity by consolidating multiple requirements into a single standardized cell structure
Solution Approach 2:
The patent performs preliminary optimization of the asymmetric layout during the design phase, pre-configuring the FinFET orientations and interconnection patterns to achieve optimal voltage characteristics. This preliminary action eliminates the need for complex post-fabrication adjustments and simplifies the overall layout process while maintaining low minimum supply voltage requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively lowers the minimum supply voltage required to operate the SRAM, enhancing power efficiency and integration density in SRAM arrays.
Implementation Method 1
fin field-effect transistors (FinFETs) having smaller size and lower power consumption
Data Source
AI summary
A Static Random Access Memory (SRAM) Cell includes a first gate electrode layer covering a channel region of a read pull-down transistor, a second gate electrode layer covering channel regions of a first pull-down transistor and a first pull-up transistor, a third gate electrode layer covering a channel region of a second pass-gate transistor, a fourth gate electrode layer covering a channel region of a read pass-gate transistor, a fifth gate electrode layer covering a channel region of a first pass-gate transistor, and a sixth gate electrode layer covering channel regions of a second pull-down transistor and a second pull-up transistor. The first and second gate electrode layers are separated from each other by a first dielectric layer interposed therebetween, and are electrically connected to each other by a first interconnection layer formed thereon.