Semiconductor Memory Device Dynamic Program Voltage Increment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Semiconductor memory devices face challenges in reliably writing data due to the deterioration of program slope, leading to increased program voltage and potential errors in high threshold voltage memory cells, which affects data integrity and operation speed.

Innovation Solution

The semiconductor memory device employs a write operation strategy that adjusts the program voltage increment (ΔVpgm) based on the progress of the write operation, reducing it after reaching a predetermined level or upon successful verification, to optimize the program slope and minimize program disturbance, thereby improving data reliability and operation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the program voltage is continuously increased to overcome program slope deterioration, then the write operation can complete, but program disturbance increases and data reliability deteriorates

Engineering Contradiction:

Improvedata reliabilityVSAvoidprogram disturbance

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies dynamics by making the program voltage increment dynamic rather than fixed. The control circuit adjusts the program voltage increment based on the current program voltage level, using a first increment for lower voltage ranges and a second (smaller) increment for higher voltage ranges. This dynamic adjustment prevents excessive program disturbance while ensuring write completion.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of program voltage increment based on the program voltage level. By switching between different increment values (first program voltage increment and second program voltage increment), the system optimizes the balance between overcoming program slope deterioration and minimizing program disturbance, thereby improving data reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If multiple program loops are executed to ensure data integrity, then data reliability improves, but write operation time increases

Engineering Contradiction:

Improvedata integrityVSAvoidwrite operation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements feedback by having the control circuit monitor the program voltage level and adjust the program voltage increment accordingly. This feedback mechanism allows the system to optimize the write operation progression, ensuring data integrity while minimizing unnecessary program loops and reducing write operation time.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9990998B2Semiconductor memory device and memory system

Publication Date: 2018.06.05 KIOXIA CORP

AI summary

A semiconductor memory device includes a plurality of memory cells, a plurality of word lines, including a word line that is connected to a group of the memory cells, and a control circuit configured to execute a write operation on the memory cells of the group. The write operation includes multiple program loops including a first program loop and a second program loop that is executed at a later time than the first program loop, and for each subsequent program loop, a program voltage that is applied to the first word line is increased from that of a current program loop. The program voltage is increased by a first amount from that of the current program loop if the next program loop is the first program loop and by a second amount that is less than the first amount if the next program loop is the second program loop.