Non-Volatile Memory State Transition Without Erase Delay
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Solution Overview
Problem
Existing non-volatile memory systems require a time-consuming erase step before overwriting data, which slows down the programming process.
Innovation Solution
A method to transition non-volatile memory cells from a programmed data state with higher threshold voltages directly to a lower threshold voltage state without going through the erased state, thereby bypassing the erase step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the traditional erase-then-program process is used, then data can be reliably overwritten, but the programming speed is slow due to the time-consuming erase step
Solution Approach 1:
The patent extracts and removes the erase step from the traditional programming process. By directly transitioning memory cells from one programmed state to another programmed state without intermediate erasure, the time-consuming erase operation is eliminated while maintaining data reliability through controlled threshold voltage transitions.
Solution Approach 2:
The patent applies preliminary actions by pre-positioning charge in specific regions of the memory cell structure (such as in the charge trap layer or floating gate) to enable direct state transitions. This preliminary charge positioning allows the memory cell to transition between programmed states without requiring full erasure, thereby speeding up the programming process.
2Loss of time
If the erase step is eliminated to speed up programming, then programming time is reduced, but the reliability of data overwriting may be compromised
Solution Approach 1:
The patent changes the threshold voltage parameter of memory cells in a controlled manner, transitioning directly from one programmed state (with higher threshold voltage) to another programmed state (with lower threshold voltage). This parameter-based transition approach eliminates the need for erasure while maintaining reliability through precise voltage control and verification processes.
Solution Approach 2:
The patent incorporates feedback mechanisms to verify that memory cells have successfully transitioned to the target programmed state. By monitoring threshold voltage levels and using verification reads, the system ensures data overwriting reliability even without the traditional erase step, allowing the process to correct or re-attempt transitions as needed.
Data Source
AI summary
A non-volatile memory is configured to transition memory cells from programmed data states with the higher ranges of threshold voltages to programmed data states with the lower ranges of threshold voltages without the transitioning the memory cells to the erased data state.