Memory Cell Segmentation for Coupling Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current memory devices face challenges in accurately reading cells due to cell-to-cell coupling and lateral migration, which cause shifts in threshold voltages, leading to errors and reduced reliability, requiring resource-intensive compensation methods that increase data transfer latency.
Innovation Solution
The approach involves segmenting wordlines into groups to achieve a sufficient read window budget increase without resorting to perfect compensation, by determining target adjustments based on voltage values and aggregating RWB increases across wordline groups, thereby reducing the need for extensive parameter modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perfect compensation methods are used to address cell-to-cell coupling and lateral migration, then bit error rate improves, but data transfer latency and resource consumption increase
Solution Approach 1:
The patent applies partial compensation by determining target adjustments to parameters (such as read voltage or program voltage) based on aggregate RWB increases across wordline groups, rather than implementing perfect compensation for every individual cell. This partial action achieves sufficient error rate improvement while avoiding the full resource cost of perfect compensation, directly resolving the contradiction between reliability and time loss.
2Measurement precision
If extensive parameter modifications are performed for compensation, then reading accuracy improves, but time and energy required for memory access operations increase
Solution Approach 1:
The patent segments the memory device into multiple wordline groups and calculates aggregate RWB increases for each group separately. This segmentation allows the system to apply compensation at the group level rather than individually to each cell, reducing the total number of parameter modifications needed while maintaining sufficient reading accuracy, thus resolving the contradiction between measurement precision and energy consumption.
Solution Approach 2:
By determining target parameter adjustments based on aggregate RWB increases rather than maximizing compensation for every cell, the patent implements partial action that achieves adequate reading accuracy without the excessive energy cost of full compensation, directly addressing the contradiction between measurement precision and energy use.
3Reliability
If resource-intensive compensation methods are applied, then threshold voltage shift errors are reduced, but productivity decreases due to increased processing time
Solution Approach 1:
The patent divides the memory device into wordline groups and performs compensation calculations at the aggregate group level, reducing the computational burden compared to individual cell processing. This segmentation maintains sufficient threshold voltage accuracy while improving memory access speed, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent implements partial compensation by determining target adjustments that achieve sufficient threshold voltage accuracy without maximizing compensation for every cell. This partial action reduces processing time and resource consumption while maintaining adequate reliability, directly resolving the contradiction between threshold voltage accuracy and memory access speed.
Data Source
AI summary
Embodiments disclosed can include determining, for each wordline group of one or more wordline groups of the plurality of wordlines, a target adjustment to a parameter of a memory access operation that is performed with respect to a memory cell associated with a wordline of the wordline group; and responsive to determining that an aggregate read window budget (RWB) increase for the block satisfies a threshold range associated with a target RWB increase, modifying the parameter of the memory access operation according to the target adjustment, wherein the target RWB increase is determined using a different PV voltage offset for each respective programming level of the memory cell associated with the wordline of the wordline group.