Memory Cell Simultaneous Sensing for Neighbor Effect Compensation

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Solution Overview

Problem

The 'neighbor effect' in non-volatile memory and flash memory arrays leads to inaccurate data reading due to current leakage from neighboring memory cells during sensing, limiting the distinguishability of programmed and erased states and efficiency in data storage.

Innovation Solution

Sensing multiple memory cells simultaneously increases the maximum current window, allowing for the storage and reading of multiple data bits while compensating for current losses, thereby enhancing memory space efficiency and reducing the impact of the neighbor effect without requiring additional pre-read operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple memory cells are sensed simultaneously, then the current window is doubled and multiple data bits can be stored, but the neighbor effect causes current leakage that may alter the sensed current

Engineering Contradiction:

Improvememory space efficiencyVSAvoiddata reading accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent combines multiple memory cells into a single sensing group where cells are sensed simultaneously. By merging the sensing operations of multiple cells, the system doubles the current window and enables storage of multiple data bits per sensing operation, thereby improving memory space efficiency without requiring additional pre-read operations

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent converts the harmful neighbor effect (current leakage to neighboring cells) into a beneficial phenomenon. By sensing multiple cells simultaneously and using the combined charge signal, the system compensates for individual cell current losses. The neighbor effect that would normally cause measurement errors is transformed into a mechanism that allows multiple cells to be read together, improving productivity while maintaining accuracy through the combined signal

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If traditional sensing is used for each memory cell individually, then reading accuracy is maintained, but memory space efficiency is reduced and additional pre-read operations are required

Engineering Contradiction:

Improvedata reading accuracyVSAvoidmemory space efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent merges multiple individual sensing operations into a single simultaneous sensing operation. By combining the read operations for multiple memory cells into one unified sensing process, the system achieves both high reading accuracy and improved memory space efficiency, eliminating the need for separate pre-read operations for each cell

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7554856B2Memory cell

Publication Date: 2009.06.30 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of reading memory includes sensing a plurality of memory cells simultaneously and providing a data signal corresponding to one of a plurality of programming states. The plurality of programming states include a number of programming states equal to twice a number of memory cells in the plurality of memory cells. The data signal is processed, providing binary data representative of the data signal. The binary data includes a number of information bits equal to the number of memory cells.