Edge Data Wordline Programming With Local Pass-Voltage Control
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Solution Overview
Problem
Edge data wordlines in memory devices experience significant program disturb effects due to hot-electron injection and electrostatic fields, leading to data corruption and inaccuracies during programming operations, which conventional voltage tuning methods cannot adequately mitigate.
Innovation Solution
An improved program scheme applies a lower pass voltage to the last unselected data wordline during programming, alongside a higher pass voltage to other unselected wordlines, reducing the voltage differential and minimizing hot-electron injection at the edge data wordlines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a uniform pass voltage is applied to all unselected wordlines during programming, then the programming operation can be simplified, but edge data wordlines experience significant program disturb effects due to hot-electron injection and electrostatic fields
Solution Approach 1:
The patent applies different pass voltages to different groups of unselected wordlines based on their position. Specifically, a first pass voltage is applied to unselected wordlines in a first group, and a second pass voltage is applied to unselected wordlines in a second group, with the second pass voltage having a lower magnitude than the first. This local differentiation reduces program disturb effects at edge data wordlines while maintaining simplified programming operations.
2Manufacturing precision
If a higher pass voltage is applied to reduce hot-electron injection at edge data wordlines, then programming accuracy improves, but the voltage differential between selected and unselected wordlines increases causing new disturbances
Solution Approach 1:
The patent changes the voltage parameter applied to unselected wordlines based on their position. By applying a first pass voltage to unselected wordlines in a first group and a second pass voltage with lower magnitude to unselected wordlines in a second group (including edge data wordlines), the patent optimizes the voltage differential to reduce both hot-electron injection and voltage differential effects, thereby improving programming accuracy while minimizing disturbances.
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 programming accuracy and reduces errors at edge data wordlines by lowering the voltage differential, thereby minimizing program disturb effects and ensuring more reliable data storage.
Implementation Method 1
Edge data wordlines in memory devices experience significant program disturb effects due to hot-electron injection and electrostatic fields
Implementation Method 2
Edge data wordlines in memory devices experience significant program disturb effects due to hot-electron injection and electrostatic fields
Data Source
AI summary
Control logic in a memory device causes a program voltage to be applied to a selected data wordline of a plurality of wordlines of a block of a memory array for a pulse duration period during a programming operation. The control logic further causes a first pass voltage to be applied to one or more unselected data wordlines of the plurality of wordlines of the block for the pulse duration period and causes a second pass voltage to be applied to a last unselected data wordline of the plurality of wordlines of the block for at least a first portion of the pulse duration period, wherein the second pass voltage has a lower magnitude than the first pass voltage.