Memory Device Select Transistor Programming Voltage Control
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Solution Overview
Problem
Nonvolatile memory devices face challenges in improving threshold voltage distribution during select transistor programming operations, which affects the efficiency and reliability of data storage.
Innovation Solution
A memory device with a memory block, peripheral circuit, and control logic that applies a coupling voltage with a positive potential to the source line during select transistor programming, along with specific voltage sequences to selected and unselected drain select transistors, to enhance the threshold voltage distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional programming operations are used on select transistors, then the programming operation can be completed, but the threshold voltage distribution of the select transistor deteriorates
Solution Approach 1:
The patent changes the voltage parameter applied to the source line from a conventional voltage to a coupling voltage with positive potential. This parameter change modifies the electrical environment during programming, enabling improved threshold voltage distribution while maintaining programming effectiveness.
Solution Approach 2:
The coupling voltage with positive potential acts as an intermediary that mediates between the programming voltage and the select transistor. This intermediary voltage influences the charge distribution and threshold voltage formation, achieving better distribution characteristics without compromising programming speed.
2Reliability
If coupling voltage with positive potential is applied to source line, then threshold voltage distribution of select transistor is improved, but the complexity of voltage control increases
Solution Approach 1:
The voltage control is segmented into distinct phases: applying coupling voltage to the source line, applying programming voltage to the selected word line, and managing voltages on bit lines. This segmentation allows each voltage parameter to be independently optimized while simplifying the overall control logic through systematic voltage management.
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 improves the threshold voltage distribution of select transistors, enhancing the programming efficiency and reliability of the memory device.
Implementation Method 1
a potential level of second bit lines connected to unselected drain select transistors among the plurality of drain select transistors is increased due to a coupling phenomenon caused by the coupling voltage
Data Source
AI summary
There are provided a memory device and an operating method thereof. The memory device includes: a memory block including a plurality of memory cells and a plurality of select transistors; a peripheral circuit for performing a program operation on selected select transistors among the plurality of select transistors in a select transistor program operation; and a control logic for controlling the peripheral circuit to perform the select transistor program operation. The peripheral circuit applies a coupling voltage having a positive potential to a source line of the memory block in the select transistor program operation.