Adaptive Programming Voltage for Non-Volatile Memory Cells

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Solution Overview

Problem

Non-volatile memory devices face issues with threshold voltage shifts due to insulative layer degradation, leading to over-programming and read errors, which existing technologies fail to address effectively.

Innovation Solution

An on-die controller in the memory die adapts programming settings by determining if the current programming voltage causes suboptimal programming and stores a revised, lower programming voltage without erasing the original setting, using a dummy word line and spare columns to store and retrieve these settings efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed programming voltage is used, then the programming process is simple, but threshold voltage shifts cause over-programming and read errors

Engineering Contradiction:

Improveread accuracyVSAvoidprogramming control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic programming voltage adjustment by monitoring threshold voltage shifts and adapting the programming voltage accordingly. The system transitions from a fixed voltage approach to a dynamic one where the programming voltage is adjusted based on real-time cell conditions, preventing over-programming while maintaining programming effectiveness

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where the programming process monitors cell state changes and uses this information to adjust subsequent programming voltages. This closed-loop control ensures that programming stops at the optimal point, avoiding over-programming while maintaining simplicity through automated voltage adaptation

Inventive Principle:

Principle #23Feedback

2Productivity

If programming voltage is increased to ensure data writing, then programming speed improves, but insulative layer degradation accelerates

Engineering Contradiction:

Improveprogramming speedVSAvoiddevice lifespan

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent dynamically changes the programming voltage parameter based on cell conditions and programming progress. By adjusting the voltage to match actual cell needs rather than using a consistently high voltage, the system maintains programming speed while reducing stress on insulative layers and extending device lifespan

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies programming voltage in controlled amounts, using just enough voltage to achieve successful programming without excessive voltage that would accelerate degradation. This partial action approach ensures sufficient programming speed while preserving device reliability

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If programming voltage is reduced to prevent over-programming, then device lifespan extends, but programming reliability decreases

Engineering Contradiction:

Improvedevice lifespanVSAvoidprogramming accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts programming voltage based on real-time monitoring of cell threshold voltage shifts. This dynamic approach allows the system to use lower voltages when appropriate (extending lifespan) while maintaining programming accuracy through continuous adaptation to cell conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The programming system performs self-adjustment by monitoring its own effectiveness and automatically modifying the programming voltage. This self-service capability ensures that the system maintains programming precision without requiring external intervention, while using minimal necessary voltage to preserve device lifespan

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10811089B2Adaptive programming voltage for non-volatile memory devices

Publication Date: 2020.10.20 SANDISK TECHNOLOGIES LLC

AI summary

Apparatuses, systems, and methods are disclosed for adjusting a programming setting such as a programming voltage of a set of non-volatile storage cells, such as an SLC NAND array. The non-volatile storage cells may be arranged into a plurality of word lines. A subset of the non-volatile storage cells may be configured to store a programming setting. An on-die controller may be configured to read the programming setting from the setting subset, and write data to the non-volatile storage cells, using the programming setting. The on-die controller may further be configured to determine that the programming setting causes suboptimal programming of one or more of the non-volatile storage cells, and in response to the determination, store a revised programming setting on the setting subset.