Row Hammer Address Latch Circuit for Memory Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor memory devices decrease in size and increase in density, they face challenges with data loss due to row hammer effects, where repeated access to a word line degrades adjacent word lines, leading to operational noise and increased data loss, especially as physical separation between memory cells decreases and charge storage capacity diminishes.
Innovation Solution
The implementation of a double stage row hammer address latch circuit that identifies and refreshes not only primary victim word lines but also secondary victim word lines, which are affected by the row hammer event, by executing row hammer refresh operations to recharge the degraded charge levels, thereby mitigating data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory devices decrease in size and increase in density, then storage capacity is improved, but data loss due to row hammer effects increases
Solution Approach 1:
The invention segments the victim word lines into primary victim word lines (immediately adjacent to aggressor word lines) and secondary victim word lines (adjacent to primary victim word lines). This segmentation allows the system to selectively refresh different groups of victim word lines based on their distance from the aggressor word lines, addressing the reliability issue while maintaining storage density.
Solution Approach 2:
The invention performs preliminary refresh actions on victim word lines before data loss occurs. By detecting row hammer events and proactively refreshing both primary and secondary victim word lines, the system prevents charge degradation and data loss that would otherwise occur due to repeated access to aggressor word lines.
2Volume of moving object
If memory cells are made physically smaller, then device size is reduced, but charge storage capacity diminishes
Solution Approach 1:
The refresh mechanism performs preliminary recharging of victim word lines before charge degradation becomes critical. This preliminary action compensates for the reduced charge storage capacity of smaller memory cells by proactively restoring charge levels, thereby maintaining reliability despite reduced cell size.
3Quantity of substance
If physical separation between memory cells decreases, then density is improved, but electromagnetic interactions increase
Solution Approach 1:
The invention segments victim word lines into multiple groups (primary and secondary) based on their spatial relationship to aggressor word lines. This segmentation enables targeted refresh operations that address electromagnetic interactions affecting different regions, allowing high density while managing the harmful electromagnetic effects through selective compensation.
4Reliability
If row hammer refresh operations are executed for both primary and secondary victim word lines, then data loss is reduced, but operational complexity increases
Solution Approach 1:
The invention manages complexity by segmenting victim word lines into distinct groups (primary and secondary) with different refresh priorities. This segmentation allows the control circuit to systematically handle different refresh scenarios, reducing the apparent complexity through structured organization of refresh operations.
Solution Approach 2:
The refresh control circuit is designed with multi-functionality to handle both primary and secondary victim word line refresh operations through a unified mechanism. This universal approach consolidates what could be separate complex systems into a single integrated control structure, managing reliability enhancement without proportionally increasing operational complexity.
Data Source
AI summary
A refresh tracking circuit and associated methods are disclosed herein. The tracking circuit may be configured to track a primary count value and a secondary count value based on addresses associated with received commands. The primary and secondary count values may be configured to control corresponding refresh operations respectively associated with a primary address and a secondary address.