Alternate Page Programming for Flash Memory Capacitive Coupling
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Solution Overview
Problem
Existing flash memory systems face challenges in improving the accuracy and performance of write operations, particularly in multi-state memory architectures where multiple pages of data are written onto each word line, due to issues like capacitive coupling between memory cells, leading to inaccuracies and inefficiencies.
Innovation Solution
A method is introduced where multiple pages of data are written page by page into adjacent word lines, followed by a refining programming operation on the first word line to enhance the accuracy of data written, thereby reducing the impact of capacitive coupling and improving data retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pages of data are written page by page into adjacent word lines, then the Yupin effect is reduced and data accuracy is improved, but the programming time and operational complexity increase
Solution Approach 1:
The programming operation is divided into multiple passes: a first pass that writes data to every other word line, and a second pass that writes data to the remaining word lines. This segmentation allows the system to reduce the Yupin effect by ensuring that when one word line is being programmed, adjacent word lines are not simultaneously being programmed, thereby reducing capacitive coupling interference while maintaining acceptable programming throughput.
2Measurement precision
If multiple pages of data are written page by page into adjacent word lines, then the Yupin effect is reduced and data accuracy is improved, but the device complexity and operational difficulty increase
Solution Approach 1:
The programming operation is divided into multiple passes: a first pass that writes data to every other word line, and a second pass that writes data to the remaining word lines. This segmentation allows the system to reduce the Yupin effect by ensuring that when one word line is being programmed, adjacent word lines are not simultaneously being programmed, thereby reducing capacitive coupling interference while maintaining acceptable programming throughput.
Solution Approach 2:
The system performs preliminary programming of alternate word lines before programming the remaining word lines. By pre-programming every other word line first, the system establishes a pattern that minimizes capacitive coupling during subsequent programming operations, as adjacent word lines will not be programmed simultaneously.
3Ease of operation
If traditional page by page writing is used, then the programming operation is simpler, but capacitive coupling between adjacent word lines causes data inaccuracies
Solution Approach 1:
The programming operation is divided into multiple passes: a first pass that writes data to every other word line, and a second pass that writes data to the remaining word lines. This segmentation allows the system to reduce the Yupin effect by ensuring that when one word line is being programmed, adjacent word lines are not simultaneously being programmed, thereby reducing capacitive coupling interference while maintaining acceptable programming throughput.
Solution Approach 2:
The system performs preliminary programming of alternate word lines before programming the remaining word lines. By pre-programming every other word line first, the system establishes a pattern that minimizes capacitive coupling during subsequent programming operations, as adjacent word lines will not be programmed simultaneously.
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 Yupin effect, allowing for more accurate data storage and retrieval without the need for extensive caching, which minimizes wear on the memory system and maintains data integrity across multiple programming passes.
Implementation Method 1
In 'hot electron injection,' a high voltage applied to the drain accelerates electrons across the substrate channel region. At the same time a high voltage applied to the control gate pulls the hot electrons through a thin gate dielectric onto the floating gate.
Implementation Method 2
In 'tunneling injection,' a high voltage is applied to the control gate relative to the substrate. In this way, electrons are pulled from the substrate to the intervening floating gate.
Implementation Method 3
For EEPROM, a memory cell is electrically erasable, by applying a high voltage to the substrate relative to the control gate so as to induce electrons in the floating gate to tunnel through a thin oxide to the substrate channel region (i.e., Fowler-Nordheim tunneling.)
Data Source
AI summary
An alternate page by page scheme for the multi-state programming of data into a non-volatile memory is presented. Pages of data are written a page at a time onto word lines of the memory. After all of the pages of data are written to a first level of resolution onto one word line, the memory goes back to the adjacent word line (on which all of the pages of data have previously been written the first level of resolution) and refines the accuracy with which the data had been written on this preceding word line. This can reduce the effects on the data of capacitive coupling between the word lines.