Charge Trapping Layer Nitrogen Doping for NVM Isolation
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Solution Overview
Problem
As non-volatile memory (NVM) elements shrink in size, fabrication imperfections lead to difficulties in differentiating logic/memory states, causing unreliable data reading and writing due to charge trapping gates holding fewer electrical charges and control electrodes' effects spreading across multiple cells, resulting in false readings.
Innovation Solution
Implementing a memory apparatus with first and second NVM cells sharing a common charge trapping layer, where a portion above the isolation structure has a higher oxygen and nitrogen concentration than within the cells, forming a continuous structure with varying electrical resistivity to minimize charge migration and loss between cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If NVM elements are shrunk to smaller scale, then memory density and integration are improved, but charge trapping gates hold fewer electrical charges causing logic states to become difficult to differentiate
Solution Approach 1:
The patent introduces an isolation structure with different material composition (higher oxygen and nitrogen concentration) than the charge trapping layer in active memory cells. This creates local quality differentiation where the isolation portion has higher electrical resistivity, preventing charge migration while maintaining charge storage capability in the memory cell regions.
Solution Approach 2:
The isolation structure acts as an intermediary element between adjacent NVM cells. It is formed as part of the continuous charge trapping layer but with modified properties (higher resistivity) that mediate charge confinement, preventing harmful charge migration between cells while allowing the overall layer to remain continuous.
2Productivity
If NVM elements are shrunk to smaller scale, then memory density is improved, but control electrode effects spread over multiple memory cells causing unreliable data reading and writing
Solution Approach 1:
The isolation structure creates local quality variation in the charge trapping layer, with isolated regions having higher electrical resistivity. This local property differentiation confines control electrode effects to specific memory cells, preventing spread to adjacent cells while maintaining overall device integration.
Solution Approach 2:
The continuous charge trapping layer is effectively segmented into isolated regions by the high-resistivity portions above isolation structures. This segmentation electrically divides the layer into discrete cell-specific zones, preventing cross-talk between adjacent memory cells despite the physical continuity of the layer.
3Ease of manufacture
If charge trapping layer is made continuous across isolation structures, then manufacturing simplicity is improved, but charge migration between adjacent NVM cells occurs causing false readings
Solution Approach 1:
The patent maintains a continuous charge trapping layer structure for manufacturing simplicity, but introduces local quality variation by creating portions with higher oxygen and nitrogen concentration above isolation structures. This local modification creates higher resistivity regions that block charge migration while preserving the overall continuous layer architecture.
Solution Approach 2:
The patent changes the compositional parameters (oxygen and nitrogen concentration) of the charge trapping layer in specific regions above isolation structures. This parameter change results in higher electrical resistivity in those regions, creating charge barriers that prevent migration while maintaining the layer's continuity and ease of fabrication.
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 enhances the reliability of NVM arrays by maintaining distinct logic/memory states and reducing false readings, ensuring accurate data storage and retrieval.
Implementation Method 1
a first portion of the common charge trapping layer that is disposed directly above the isolation structure may have a higher oxygen concentration than second portions of the common charge trapping layer that are disposed within the first and second NVM cells
Data Source
AI summary
An example embodiment comprises a method for fabrication of a non-volatile memory (NVM) device. An isolation structure is formed in a substrate between first and second locations for first and second NVM cells. A common charge trapping layer is formed as a continuous structure over the substrate, where a first portion of the charge trapping layer is disposed directly over the isolation structure and second portions of the charge trapping layer are disposed directly over the first and second substrate locations. Nitrogen doping of the first portion of the charge trapping layer is performed, where after the nitrogen doping is performed the first portion of the charge trapping layer includes a higher nitrogen concentration than the second portions. The first and second NVM cells are then formed over the first and second substrate locations, where the first and second NVM cells include the second portions of the charge trapping layer.