Weighted Programming Patterns for Read Disturb Compensation
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Solution Overview
Problem
Solid-state memory devices face challenges in data retention and read disturb effects, leading to decoding failures and reduced endurance, as charge loss and gain affect the ability to correctly interpret stored data over time and with frequent reads.
Innovation Solution
Implementing weighted programming patterns that favor either lower or higher voltage threshold states in solid-state memory devices to reduce charge loss and gain, thereby improving data retention and read disturb margins by strategically programming cells to minimize bit error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data is programmed into solid-state memory cells, then data storage capacity is improved, but charge loss and read disturb effects increase leading to decoding failures
Solution Approach 1:
The patent applies parameter changes by modifying the voltage threshold distribution of programmed cells. Instead of uniform programming, the system uses weighted programming patterns that deliberately create non-uniform voltage threshold distributions, favoring certain voltage states over others. This parameter modification compensates for charge loss and read disturb effects, maintaining reliable data interpretation even as storage capacity increases.
Solution Approach 2:
The patent implements preliminary anti-action through read disturb compensation techniques. Before reading data, the system pre-charges or pre-adjusts the voltage thresholds of cells that are susceptible to read disturb effects. This preliminary action counteracts the harmful charge gain that would otherwise occur during subsequent read operations, preventing decoding failures before they happen.
2Duration of action of stationary object
If weighted programming patterns are applied to reduce bit error rates, then data retention is improved, but programming complexity increases
Solution Approach 1:
The patent manages programming complexity by systematically changing programming parameters using predefined weight patterns. Rather than implementing complex error correction algorithms, the system modifies the programming weights assigned to different cells based on their susceptibility to charge loss. This parameter-based approach extends data retention while keeping the programming scheme relatively simple and efficient.
3Duration of action of stationary object
If cells are programmed with higher voltage threshold states to reduce charge loss, then data retention is improved, but read disturb margins are reduced
Solution Approach 1:
The patent applies local quality by treating different memory cells differently based on their individual characteristics. Instead of uniformly programming all cells to high voltage states, the system assigns different weight patterns to different cells or cell groups. Cells more susceptible to charge loss receive higher voltage programming, while cells in regions prone to read disturb receive adjusted programming that balances both concerns. This localized approach optimizes both data retention and read disturb margins simultaneously.
Data Source
AI summary
A data storage device includes a solid-state non-volatile memory including a plurality of memory cells and a controller. The controller is configured to reduce a read disturb effect of at least a portion of the solid-state non-volatile memory at least in part by receiving or accessing data to be written to the solid-state non-volatile memory, encoding the data using a programming pattern that favors a first programming state over a second programming state, the first programming state being associated with a higher voltage level than the second programming state, and writing the encoded data to the solid-state non-volatile memory.