Memory Device Verification to Detect Read Interference Before Programming
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Solution Overview
Problem
Existing memory devices face inefficiencies due to read interference causing shifts in threshold voltages, leading to programming and read errors, particularly in open memory blocks with high usage, which affects operating efficiency.
Innovation Solution
Implement a memory device and system that includes a peripheral circuit to perform a first verification operation, counting memory cells with shifted threshold voltages and generating a failure identifier when a threshold is exceeded, allowing the system to quit programming and reprogram affected cells, thereby reducing read interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If read operations are performed frequently in open memory blocks, then data accessibility is improved, but threshold voltage shifts occur causing programming errors
Solution Approach 1:
The patent performs a verification operation before programming to detect threshold voltage shifts in advance. By counting memory cells with shifted threshold voltages and generating a failure identifier when the count exceeds a threshold, the system proactively identifies read interference issues before they cause programming errors, allowing preventive measures to be taken
Solution Approach 2:
The patent implements a feedback mechanism where the verification operation results (count of cells with shifted threshold voltages) are used to control subsequent programming operations. When the count exceeds the threshold, the system generates a failure identifier that feedbacks to stop or adjust programming, creating a closed-loop control system that adapts to read interference conditions
2Reliability
If verification operations are added to detect threshold voltage shifts, then programming reliability is improved, but operating complexity increases
Solution Approach 1:
The patent employs the memory device's own existing verification circuitry to perform the detection function. The peripheral circuit uses the same verification mechanism already present in the memory device to count cells with shifted threshold voltages, eliminating the need for additional external detection equipment and reducing overall system complexity
Solution Approach 2:
The patent makes the existing verification operation serve dual purposes: its traditional function of verifying programming results and the new function of detecting read interference by counting cells with shifted threshold voltages. This multi-functional use of existing circuitry avoids adding separate detection mechanisms, thereby controlling complexity
Data Source
AI summary
Implementations of the present disclosure provide a memory device, a memory system and a control method thereof. An example memory device includes: a memory block including a plurality of memory cells; a plurality of word lines coupled to the memory block; and a peripheral circuit coupled to the plurality of word lines and configured to: perform a first programming operation in response to a first operation command to program first memory cells; perform a first verification operation to obtain the first number of second memory cells that are coupled to the first word line, have an erased state as the target state and have a threshold voltage larger than a first verification voltage, which is a verification voltage of the first programmed state; and generate a first state identifier indicating a programming failure in response to the first number being larger than a first threshold.