3D Flash Memory Precharge Control for Program Disturbance
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Solution Overview
Problem
The increasing number of stacked layers in three-dimensional flash memory devices leads to serious program disturbance due to Fowler-Nordheim tunneling and Hot Carrier Injection, narrowing the threshold voltage window and affecting reliability.
Innovation Solution
Implementing a stepwise increasing trend in precharge voltages during program cycles, with each cycle having progressively higher precharge voltages applied to conductive lines and word lines, to mitigate program disturbance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked layers in three-dimensional flash memory devices is increased to improve storage capacity, then storage density is improved, but program disturbance due to Fowler-Nordheim tunneling and Hot Carrier Injection becomes more serious, narrowing the threshold voltage window and affecting reliability
Solution Approach 1:
The patent applies preliminary action by implementing a precharge stage before the program operation. During this precharge stage, a precharge voltage is applied to the conductive line to establish a controlled potential distribution in advance. This preliminary voltage application mitigates the program disturbance caused by Fowler-Nordheim tunneling and Hot Carrier Injection before they can severely affect the threshold voltage window, thereby maintaining reliability while enabling increased storage capacity through additional stacked layers.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the precharge voltage applied to conductive lines during different program cycles. The precharge voltage is modified based on the program cycle number and the specific conductive line being operated on. This parameter adjustment optimizes the potential distribution to suppress program disturbance mechanisms (Fowler-Nordheim tunneling and Hot Carrier Injection) while maintaining the ability to program additional stacked layers, thus resolving the contradiction between storage capacity and reliability.
2Reliability
If precharge voltage is applied to conductive lines during program cycles to suppress program disturbance, then reliability is improved, but the complexity of voltage control increases
Solution Approach 1:
The patent applies segmentation by dividing the program operation into distinct stages: a precharge stage followed by a program stage. Each stage has specific voltage control requirements. During the precharge stage, precharge voltages are applied to conductive lines; during the program stage, program voltages are applied to word lines. This segmentation simplifies the overall voltage control complexity by breaking down the complex multi-voltage operation into manageable, sequential stages with clearly defined voltage control rules for each stage.
Solution Approach 2:
The patent employs dynamics by implementing adaptive voltage control where the precharge voltage parameters change dynamically based on the program cycle number and the specific conductive line being operated on. The voltage control is not static but adapts to the operational context, allowing the system to maintain optimal suppression of program disturbance while managing complexity through context-dependent parameter adjustment rather than fixed complex control logic.
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
Effectively suppresses program disturbance and enhances the reliability of three-dimensional flash memory devices by improving Fowler-Nordheim tunneling and hot carrier injection effects.
Implementation Method 1
The increasing number of stacked layers in three-dimensional flash memory devices leads to serious program disturbance due to Fowler-Nordheim tunneling and Hot Carrier Injection
Implementation Method 2
The increasing number of stacked layers in three-dimensional flash memory devices leads to serious program disturbance due to Fowler-Nordheim tunneling and Hot Carrier Injection
Data Source
AI summary
The present disclosure provides a memory device and an operation method thereof, a memory system, and a computer readable storage medium. The memory device includes: a memory array and a peripheral circuit coupled with the memory array. The memory array includes a plurality of memory cell strings and a conductive line coupled with one end of a memory cell string. The peripheral circuit is configured to: apply a first precharge voltage to the conductive line in a precharge stage of a first program cycle; and apply a second precharge voltage to the conductive line in a precharge stage of a second program cycle after the first program cycle, wherein the second precharge voltage is greater than the first precharge voltage.