Non-volatile Memory Conductive Cover Layers Suppress Fringing Field
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Solution Overview
Problem
As flash memory devices are downscaled and multi-level programming is implemented, the data retention characteristics and program-erase cycling characteristics deteriorate due to charge trapping in inter-memory cell areas, leading to potential read errors and reliability issues.
Innovation Solution
A non-volatile memory device is designed with conductive cover layers having a higher work function than the control gates, which suppresses the fringing field and prevents program charges from accumulating in inter-memory cell areas, improving data retention and program-erase cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are downscaled to increase integration and capacity, then device density and storage capacity are improved, but data retention characteristics deteriorate due to charge spreading to adjacent cells
Solution Approach 1:
The patent introduces conductive cover layers on control gates that segment the electric field distribution, creating localized field confinement zones. This segmentation prevents charge spreading between adjacent memory cells while maintaining high-density cell arrangement, thus resolving the contradiction between increased storage capacity and data retention reliability.
Solution Approach 2:
The conductive cover layers modify the local electric field characteristics at control gate regions, creating non-uniform field distribution that confines charges locally. This local quality change ensures that each memory cell maintains its charge independently even in downscaled configurations, improving data retention while preserving high density.
2Reliability
If conductive cover layers with higher work function are added to control gates, then charge accumulation in inter-memory cell areas is suppressed, but device complexity increases
Solution Approach 1:
The patent changes the work function parameter of the control gate material by adding conductive cover layers with higher work function. This parameter change fundamentally alters the electric field distribution and charge trapping characteristics, suppressing charge accumulation in inter-cell areas. The solution achieves improved charge retention through material parameter optimization rather than complex structural modifications.
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
The solution effectively minimizes charge accumulation in inter-memory cell areas, enhancing data retention and program-erase cycling characteristics, thereby improving the reliability and efficiency of flash memory devices.
Implementation Method 1
conductive cover layers having a higher work function than the control gates, which suppresses the fringing field and prevents program charges from accumulating in inter-memory cell areas
Implementation Method 2
conductive cover layers having a higher work function than the control gates, which suppresses the fringing field and prevents program charges from accumulating in inter-memory cell areas
Data Source
AI summary
Provided are a non-volatile memory device and a method of fabricating the same. The non-volatile memory includes a channel layer, a data storage layer disposed on the channel layer, a plurality of control gates arranged on the data storage layer and spaced apart from one another, and conductive cover layers disposed on sidewalls of the control gates facing each other. The plurality of control gates includes a first conductor having a first work function. The conductive cover layers include a second conductor having a second work function that is greater than the first work function.