Multi-Bit Memory Cell Readout Using Staged Verification Voltages
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Solution Overview
Problem
Existing memory devices face challenges in efficiently storing and retrieving multiple bits of data per cell transistor while maintaining high speed and reliability, particularly in applications requiring rapid data processing and storage.
Innovation Solution
The memory device employs a configuration with a memory cell, word line, bit line, and transistors, utilizing a charge accumulation film to store data non-volatilely, and a sense amplifier circuit to determine the state of cell transistors, enabling 3-bit storage per cell transistor through precise threshold voltage control and read operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple bits of data are stored per cell transistor, then storage density is improved, but read operation speed and reliability deteriorate
Solution Approach 1:
The patent divides the verification process into multiple stages (first verification and second verification) with different voltage levels. The first verification uses a first verification voltage to determine a first state, and the second verification uses a second verification voltage to determine a second state. This segmentation allows the sense amplifier to handle complex multi-bit states systematically, improving both storage density and read reliability by breaking down the verification into manageable steps rather than attempting to read all bits simultaneously.
Solution Approach 2:
The patent employs different verification voltages (first verification voltage and second verification voltage) to detect different states of the cell transistor. By changing the voltage parameter during verification, the system can distinguish between multiple storage states without requiring a single complex read operation. This parameter change approach enables high-density storage while maintaining read speed and reliability through voltage-based state differentiation.
2Quantity of substance
If multiple bits of data are stored per cell transistor, then storage density is improved, but reliability deteriorates
Solution Approach 1:
The verification process is segmented into multiple stages with different voltage levels. The first verification stage uses a first verification voltage to determine a first state, and the second verification stage uses a second verification voltage to determine a second state. This segmentation improves reliability by performing multiple checks at different voltage thresholds, ensuring data integrity for multi-bit storage without relying on a single potentially erroneous read operation.
Solution Approach 2:
The sense amplifier circuit provides feedback signals (first signal and second signal) based on the verification results at different voltage levels. The output signals indicate the storage states detected during verification, allowing the system to verify data integrity and correct potential errors. This feedback mechanism ensures reliable multi-bit storage by continuously monitoring and validating the stored data states.
3Productivity
If high speed data storage is implemented, then productivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses different verification voltages to detect different states, which simplifies the manufacturing precision requirements compared to single-voltage high-speed read operations. By changing the voltage parameter during verification, the system can achieve high storage speeds while the voltage thresholds provide built-in tolerance margins that reduce the stringency of manufacturing precision requirements for threshold voltage control.
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 configuration allows for high-speed data storage and retrieval with improved reliability, enabling efficient 3-bit storage per cell, enhancing data integrity and reducing operational latency.
Implementation Method 1
utilizing a charge accumulation film to store data non-volatilely
Data Source
AI summary
A memory device includes a memory cell, a word line coupled to the memory cell, a bit line coupled to the memory cell, a first transistor, a first latch, a second transistor, and a third transistor. The first transistor has a gate coupled to a first node coupled to the bit line, and is coupled to a second node. The first latch circuit is coupled to the second node and includes a third node. The second transistor is coupled between the first node and a fourth node A gate of the second transistor coupled to a node different from the third node. The third transistor is coupled between the first node and the fourth node A gate of the third transistor is coupled to the third node.