Flash Memory Channel Segmentation for Low-Voltage HCI Programming
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Solution Overview
Problem
Nonvolatile memory devices face inefficiencies in program operations due to high overhead and performance degradation, particularly in multi-bit flash memory devices where high program voltages lead to disturbances during verification, read, and erase operations.
Innovation Solution
The implementation of a hot carrier injection (HCI) program method that divides the channel of a selected cell string into first and second side channels by applying switching voltages, boosting voltages during specific intervals, and performing HCI operations to reduce the program voltage needed and minimize overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high program voltage is applied to multi-bit flash memory devices, then program operation speed is improved, but disturbances occur during verification, read, and erase operations
Solution Approach 1:
The patent divides the channel of a selected cell string into first and second side channels by applying switching voltages to switching memory cells. This segmentation allows independent voltage control of different channel portions, enabling high program voltage to be applied to the selected memory cell while maintaining low voltage in other regions, thus preventing disturbances during verification, read, and erase operations while achieving fast program speed.
2Productivity
If high program voltage is applied to memory cells, then program operation performance is improved, but overhead in peripheral circuits increases
Solution Approach 1:
The patent employs dynamic voltage control by applying switching voltages to switching memory cells during program operations. The switching voltages are applied only during specific program loops and removed during verification, read, and erase operations. This dynamic approach enables high program performance when needed while minimizing peripheral circuit overhead during other operations, as the switching mechanism allows rapid voltage transitions without requiring permanent high-voltage infrastructure.
3Use of energy by moving object
If switching voltages are applied to divide the channel into side channels, then program voltage requirement is reduced, but operation complexity increases
Solution Approach 1:
The patent changes voltage parameters dynamically by applying switching voltages to switching memory cells during program operations. By adjusting the switching voltage levels and timing, the patent reduces the program voltage requirement for selected memory cells while maintaining appropriate voltage levels for other operations. The switching mechanism allows parameter changes without requiring additional hardware complexity, as it uses existing memory cell structures to control voltage distribution.
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 approach enhances program performance by reducing the required program voltage, decreasing overhead in peripheral circuits, and improving overall operation efficiency in nonvolatile memory devices.
Implementation Method 1
performing a hot carrier injection (HCI) program operation on the selected memory cell corresponding to the first side channel or the second side channel by dropping the boosted first voltage of the first side channel through a selected bit line connected to the selected cell string
Data Source
AI summary
A program method of a nonvolatile memory device that performs a plurality of program loops is provided. At least one of the plurality of program loops includes dividing a channel of a selected cell string into a first side channel and a second side channel during a first interval and a second interval, turning off a string selection transistor of the selected cell string by applying a string select line voltage of a first level during the first interval, and boosting a first voltage of the first side channel and a second voltage of the second side channel, and turning on the string selection transistor by applying the string select line voltage of a second level different from the first level during the second interval, and performing a hot carrier injection (HCI) program operation on a selected memory cell corresponding to the first side channel or the second side channel.