Non-volatile Memory Read Disturbance Control
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Solution Overview
Problem
Non-volatile memory devices face challenges in maintaining data integrity due to hot carrier injection, which causes boosting charges that can deteriorate memory cell characteristics during read operations, leading to read disturbances and data loss.
Innovation Solution
A non-volatile memory device with a controller that applies specific voltage pulses to the common source line and ground select lines during read operations to remove boosting charges, preventing hot carrier generation and ensuring data accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If read voltage is applied to memory cells during read operations, then data can be retrieved, but hot carrier injection occurs causing boosting charges that deteriorate memory cell characteristics
Solution Approach 1:
The patent applies a control pulse to the common source line before the main read operation to pre-establish a safe voltage condition. This preliminary action prevents hot carrier injection by ensuring the common source line is at the appropriate voltage level before the read voltage is applied to the memory cells, thereby maintaining reliability while enabling data retrieval.
Solution Approach 2:
The common source line acts as an intermediary element between the read voltage application and the memory cells. By controlling the voltage on the common source line independently through the control pulse, the patent mediates the interaction between the read operation and the memory cells, preventing direct harmful effects while allowing the read function to operate.
2Ease of operation
If conventional read operations are performed without additional control pulses, then the operation is simple and fast, but boosting charges cause read disturbances and data loss
Solution Approach 1:
The patent introduces a periodic control pulse signal that is applied at specific intervals during the read operation. This periodic action (control pulse followed by read operation) maintains data integrity by preventing hot carrier injection at critical moments, while the overall operation remains straightforward and integrated into the standard read sequence.
3Reliability
If voltage control is applied to prevent hot carrier injection, then data integrity is maintained, but the operation time increases due to additional control sections
Solution Approach 1:
The control pulse is applied continuously or in a continuous manner during the critical read operation period. This continuous control ensures that the common source line maintains the appropriate voltage level throughout the read operation, preventing hot carrier injection at any point in time while minimizing interruptions to the overall read process.
Data Source
AI summary
A non-volatile memory device including: a first string including a first string select transistor, a first memory cell and a first ground select transistor, a second string including a second string select transistor, a second memory cell and a second ground select transistor, and a controller to apply a pass voltage to a first string select line from a first time, apply a first read voltage to a first word line during a first read section from the first time to a second time, apply a first ground select line voltage to a first ground select line from the first time, apply a ground voltage to a second string select line, apply the first ground select line voltage to a second ground select line during a first control section, and apply a first common source line voltage to a common source line during the first control section.