Preconditioning Current Stabilizes Non-Volatile Memory Threshold Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-volatile memory devices face increased operational errors due to the closer packing of smaller memory cells, leading to errors during programming and reading, which can result in data corruption and increased processing times.
Innovation Solution
A preconditioning current is applied through a group of memory cells before a read operation to stabilize the threshold voltage, mimicking the cell current during programming verification and reducing electron trapping effects that cause read errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are scaled down and packed more densely to increase memory capacity, then memory capacity per die area is improved, but operational errors increase
Solution Approach 1:
A preconditioning current is applied to the memory cells before the actual read operation to stabilize their electrical characteristics. This preliminary action prevents threshold voltage shifts that would otherwise cause read errors, thereby maintaining reliability despite increased cell density
Solution Approach 2:
The patent changes the electrical parameters of the memory cells by applying a preconditioning current that modifies the threshold voltage to a stable value before sensing. This parameter adjustment ensures accurate reading even as cell dimensions are reduced and cells are packed more densely
2Reliability
If a preconditioning current is applied to stabilize threshold voltage and reduce read errors, then data reliability is improved, but additional processing time is required
Solution Approach 1:
The preconditioning current is applied periodically only when needed - specifically before read operations that are susceptible to threshold voltage shifts. This periodic application maintains data reliability while minimizing the time overhead compared to continuous application
Solution Approach 2:
The patent implements selective preconditioning where the preconditioning current is applied only to specific memory cells or blocks that require stabilization, rather than to the entire memory array. This skipping approach reduces the overall processing time while still improving data reliability where needed
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 reduces the fail bit count by stabilizing the threshold voltage, thereby improving data reliability and reducing errors associated with reading and verification operations.
Implementation Method 1
reducing electron trapping effects that cause read errors
Data Source
AI summary
Reduced errors when sensing non-volatile memory are provided by applying a current spike or preconditioning current for a group of memory cells included a selected cell. During a sense operation, a preconditioning current can be passed through a group of non-volatile memory cells. The preconditioning current is provided prior to applying at least one reference voltage to a selected word line. The preconditioning current may simulate a cell current passing through the channel during a verification phase of programming. The preconditioning current can modify a channel resistance to approximate a state during verification to provide a more stable threshold voltage for the memory cells. Preconditioning currents may be applied selectively for select reference levels, select pages, and/or select operations. Selective application of preconditioning currents based on temperature is also provided.