Flash Memory Word-Line Biasing to Reduce Program Interference

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Solution Overview

Problem

Existing flash memory devices face challenges in achieving high read and write speeds, long service life, and reliability due to issues such as program interference and noise disturbances caused by hot carrier injection and capacitive coupling noise.

Innovation Solution

The introduction of dummy word lines and adaptive voltage application during the channel preparation phase to reduce noise interference and hot carrier injection, coupled with a multi-level program mode to enhance reliability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional programming operations are performed on flash memory devices, then data storage capacity is achieved, but program interference and hot carrier injection cause threshold voltage shifts and reduce reliability

Engineering Contradiction:

Improvedata integrityVSAvoidprogram interference

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by introducing dummy word lines and applying specific voltages during channel preparation phase to counteract the harmful effects of hot carrier injection and capacitive coupling noise before the actual programming operation occurs. This pre-compenation approach prevents threshold voltage shifts in non-programmed memory cells by establishing protective voltage conditions in advance.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent uses dummy word lines as intermediary elements to mediate between the programming operation and the memory cells. These dummy word lines act as buffers that absorb or redirect harmful electrical effects, protecting the actual memory cells from program interference and hot carrier injection while allowing the programming operation to proceed normally.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If programming speed is increased to improve write performance, then productivity increases, but noise disturbances and program interference worsen

Engineering Contradiction:

Improvewrite speedVSAvoidnoise disturbances

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary action by performing channel preparation operations before the actual programming phase. During this preparation phase, specific voltages are applied to dummy word lines and memory cells to establish stable electrical conditions, thereby reducing noise disturbances and program interference that would otherwise occur at high programming speeds.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the programming operation into distinct phases: channel preparation phase and actual programming phase. This segmentation allows for optimized voltage application in each phase, enabling high write speeds during programming while maintaining low noise levels during the preparation phase through controlled voltage application to dummy word lines.

Inventive Principle:

Principle #1Segmentation

3Loss of information

If multi-level programming is implemented to increase storage capacity, then quantity of information increases, but complexity of voltage management and program interference increase

Engineering Contradiction:

Improvestorage capacityVSAvoidvoltage management

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the dummy word line structure and voltage application methodology to serve multiple functions simultaneously: protecting against hot carrier injection, reducing capacitive coupling noise, and enabling multi-level programming operations. This multi-functional approach increases storage capacity while managing the complexity of voltage management through a unified control strategy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The proposed solution significantly reduces program interference and noise disturbances, improving the reliability and performance of flash memory devices by minimizing threshold voltage shifts and enhancing data integrity.

Implementation Method 1

program interference and noise disturbances caused by hot carrier injection and capacitive coupling noise

Methodology Applied

Scientific EffectHot carrier injection:

Implementation Method 2

program interference and noise disturbances caused by hot carrier injection and capacitive coupling noise

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS20250378881A1Memory devices, methods for operating memory devices and memory systems

Publication Date: 2025.12.11 YANGTZE MEMORY TECH CO LTD

AI summary

The present application provides a memory device, a method for operating a memory device, and a memory system. The memory device includes a memory array and a peripheral circuit coupled to the memory array, the memory array includes a memory block, and the memory block is coupled to the peripheral circuit through a word line. The memory block includes programmed memory cells and an unprogrammed memory cell, and the programmed memory cells include a first and a second memory cell. The peripheral circuit is configured to: perform a program operation on a third memory cell in the memory block, apply a first voltage to a first word line coupled to the first memory cell in a first phase of a channel preparation phase of the program operation; and apply a second voltage to a second word line coupled to the second memory cell.