Memory Device Verification Circuit for Excessive Threshold Voltage

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Solution Overview

Problem

Existing memory devices face challenges in efficiently verifying program operations due to physical defects that cause threshold voltage distributions to overlap, leading to read failures and data loss, which affects the reliability and utilization efficiency of memory systems.

Innovation Solution

A memory device and system that include a control circuit with first and second verification components to count excessive memory cells and failed bits after programming, outputting a pass or fail signal based on threshold values, ensuring accurate program verification and preventing data loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a program operation is performed in a memory device, then data is stored in memory cells, but physical defects cause threshold voltage distributions to overlap leading to read failures and data loss

Engineering Contradiction:

Improveprogram operation reliabilityVSAvoiddata loss

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by performing a verification operation immediately after the program operation to detect excessively high threshold voltages before they cause read failures. The control circuit counts excessive memory cells and determines whether to issue a pass or fail signal, preventing data loss by identifying programming errors early in the process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the verification operation results to provide information about program operation quality. The control circuit counts excessive memory cells based on threshold voltage measurements and uses this feedback to determine program success, enabling continuous improvement of programming reliability and prevention of data loss through real-time monitoring.

Inventive Principle:

Principle #23Feedback

2Reliability

If verification operations are performed to detect excessive memory cells, then program operation reliability is improved, but device complexity increases due to additional verification components

Engineering Contradiction:

Improveprogram verification accuracyVSAvoidverification circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the verification operation to use the same read circuitry and control logic already present in the memory device. The control circuit performs both normal read operations and verification operations using the same hardware components, allowing the system to gain enhanced verification capability without adding dedicated verification hardware, thus reducing device complexity while maintaining reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11373717B2Verification of an excessively high threshold voltage in a memory device

Publication Date: 2022.06.28 MIMIRIP LLC

AI summary

A memory device may include: a control circuit comprising a first verification component suitable for counting the number of memory cells in the selected word line having an excessively high threshold voltage as excessive memory cells, after a program operation is completed; and a second verification component suitable for counting the number of failed bits when the number of excessive memory cells counted is greater than or equal to an excess threshold value, and suitable for outputting a pass or fail signal for the program operation according to the count of at least one of the first verification component and the second verification component.