SRAM Bit Flip Resistance via Integrated Capacitor Gate
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Solution Overview
Problem
SRAM memory cells are prone to accidental bit flipping due to interference from particles or laser attacks, leading to data inversion errors, which existing solutions like error-correcting codes and physical separation of bits do not adequately address.
Innovation Solution
Incorporating a filtering capacitor within the SRAM cell, formed by an MOS transistor with a gate dielectric and a capacitor having electrodes separated by a second gate dielectric, increases the energy required for bit flipping, enhancing noise immunity and data stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error-correcting codes and physical separation of bits are used to suppress bit-flipping errors, then data reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the capacitor and transistor gate into a single integrated structure where the capacitor's first electrode is formed by the transistor gate region itself. This merging eliminates the need for separate capacitor structures and interconnects, reducing device complexity while maintaining the noise immunity benefits of capacitance.
Solution Approach 2:
The transistor gate serves dual functions: as the control electrode for the transistor and as the first electrode of the capacitor. This multi-functionality reduces the number of components needed while providing both transistor operation and noise filtering capabilities.
2Reliability
If a filtering capacitor is added to the SRAM cell to increase energy required for bit flipping, then noise immunity is improved, but device complexity increases
Solution Approach 1:
The capacitor is merged with the transistor structure by using the gate region as the first electrode. This integration means the capacitor functionality is added without requiring a completely separate capacitor structure, thereby improving noise immunity while minimizing the increase in device complexity.
Solution Approach 2:
The gate structure performs both transistor control and capacitor storage functions simultaneously. This multi-functionality allows the system to gain noise immunity benefits without proportionally increasing device complexity.
3Reliability
If a capacitor with separate electrodes and gate dielectric is integrated into the SRAM cell, then bit flipping resistance is improved, but manufacturing precision requirements increase
Solution Approach 1:
By merging the capacitor first electrode with the transistor gate, the patent reduces the number of separate layers and interfaces that need to be precisely manufactured. The gate dielectric already present in the transistor structure serves as the capacitor dielectric, eliminating the need for additional precise dielectric layer deposition.
Solution Approach 2:
The existing gate dielectric structure serves dual purposes as both the transistor gate insulator and the capacitor dielectric layer. This multi-functionality reduces manufacturing precision requirements by reusing existing structures rather than requiring additional precisely-controlled layers.
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
The solution significantly reduces the risk of bit flipping by increasing the energy needed to invert the flip-flop in SRAM cells, thereby improving data reliability and stability during power cuts and reload operations.
Implementation Method 1
a capacitor having a first electrode formed by the gate region of the transistor and a second electrode located above said first electrode and separated from the first electrode by a second gate dielectric
Data Source
AI summary
A semiconductor structure includes first and second source/drain region disposed in a semiconductor body and spaced from each other by a channel region. A gate electrode overlies the channel region and a capacitor electrode is disposed between the gate electrode and the channel region. A first gate dielectric is disposed between the gate electrode and the capacitor electrode and a second gate dielectric disposed between the capacitor electrode and the channel region. A first electrically conductive contact region is in electrical contact with the gate electrode and a second electrically conductive contact region in electrical contact with the capacitor electrode. The first and second contact regions are electrically isolated from one another.