Nonvolatile Memory Programming with Split Channels and HCI

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Solution Overview

Problem

Nonvolatile memory devices face inefficiencies in program operations due to high overhead and performance limitations, particularly in multi-bit flash memory devices where high program voltages can cause disturbances during verification, read, and erase operations, leading to deteriorated overall performance.

Innovation Solution

The implementation of a program method for nonvolatile memory devices that utilizes hot carrier injection (HCI) in conjunction with F-N tunneling, where the channel of a selected cell string is divided into side channels, and voltages are strategically boosted and dropped to control electron injection, reducing the need for high program voltages and minimizing overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If high program voltage is applied to multi-bit flash memory devices, then program speed is improved, but disturbances occur during verification, read, and erase operations

Engineering Contradiction:

Improveprogram speedVSAvoiddisturbances during verification, read, and erase operations

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The channel of the selected cell string is divided into a first side channel and a second side channel based on a switching memory cell. This segmentation allows independent voltage control of each side channel, enabling the first side channel to be boosted for program operations while the second side channel is suppressed to prevent disturbances during verification, read, and erase operations.

Inventive Principle:

Principle #1Segmentation

2Productivity

If high program voltage is used, then program operation effectiveness is improved, but overhead in peripheral circuits increases

Engineering Contradiction:

Improveprogram operation effectivenessVSAvoidoverhead in peripheral circuits

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the voltage parameters dynamically by boosting the first side channel voltage to a first voltage level during program operations and suppressing it to a second voltage level during verification, read, and erase operations. This parameter change enables effective program operations with lower overall voltage requirements, reducing overhead in peripheral circuits while maintaining program operation effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If program voltage is increased to improve program performance, then data retention is compromised due to disturbances

Engineering Contradiction:

Improveprogram performanceVSAvoiddata retention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies different voltage qualities to different regions: the first side channel receives a boosted voltage level for effective program operations, while the second side channel receives a suppressed voltage level to prevent disturbances. This local quality differentiation ensures high program performance in the active region while maintaining data retention reliability in the inactive region.

Inventive Principle:

Principle #3Local quality

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 data retention in multi-bit flash memory devices, thereby increasing overall efficiency and reducing disturbances during operations.

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

Methodology Applied

Scientific EffectHot carrier injection (HCI):

Implementation Method 2

applying a switching voltage to a switching memory cell disposed between a first memory cell group and a second memory cell group so as to block charge transfer between a first side channel corresponding to the first memory cell group and a second side channel corresponding to the second memory cell group

Methodology Applied

Scientific EffectCharge blocking:

Implementation Method 3

turning off a string selection transistor by applying a string select line voltage of a first level to a gate of the string selection transistor of the selected cell string 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

Methodology Applied

Scientific EffectField effect transistor conduction:

Data Source

PatentUS20250014646A1Nonvolatile memory device and program method of the same

Publication Date: 2025.01.09 SAMSUNG ELECTRONICS CO LTD

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.