Dual Silicon Oxynitride Tunneling Films for Memory Data Retention
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Solution Overview
Problem
Existing nonvolatile memory devices face challenges in improving data retention, particularly in maintaining secure data storage when electrical power is lost or removed.
Innovation Solution
A memory structure comprising a charge trapping layer with a first silicon oxynitride tunneling film and a second silicon oxynitride tunneling film, where the second film is formed through a free radical oxidation process, resulting in a higher barrier height and optimized nitrogen and oxygen atom concentration ratios, enhancing data retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer silicon oxynitride tunneling film is used, then the manufacturing process is simple, but the data retention is insufficient
Solution Approach 1:
The tunneling film is divided into multiple layers with different compositions and functions. The first silicon oxynitride tunneling film (higher N content, 10-50% nitrogen atom concentration ratio) provides charge trapping capability, while the second silicon oxynitride tunneling film (lower N content, 1-15% nitrogen atom concentration ratio) provides a higher barrier height. This segmentation allows each layer to optimize its specific function, resolving the contradiction between data retention and structural complexity.
Solution Approach 2:
Different regions of the tunneling film structure are given different local qualities through varying nitrogen and oxygen concentrations. The first tunneling film layer has higher nitrogen content for charge trapping, while the second layer has lower nitrogen content for higher barrier height. This local quality differentiation enables the structure to simultaneously achieve both data retention and reduced complexity compared to a uniformly complex multi-layer structure.
2Reliability
If the nitrogen atom concentration in the silicon oxynitride tunneling film is increased to improve charge trapping, then the charge trapping capability is enhanced, but the barrier height decreases
Solution Approach 1:
The tunneling film is segmented into two layers with different nitrogen concentrations. The first layer (closer to the charge trapping layer) has higher nitrogen content (10-50% nitrogen atom concentration ratio) to enhance charge trapping capability, while the second layer (outer layer) has lower nitrogen content (1-15% nitrogen atom concentration ratio) to maintain a higher barrier height. This segmentation resolves the contradiction by spatially separating the conflicting requirements.
Solution Approach 2:
Different nitrogen concentrations are applied locally to different regions of the tunneling film structure. The inner region (first layer) has high nitrogen content for charge trapping, while the outer region (second layer) has low nitrogen content for barrier height. This local quality optimization allows the structure to simultaneously satisfy both charge trapping and barrier height requirements that cannot be met by a uniform composition.
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 proposed memory structure significantly improves data retention by increasing the barrier height of the silicon oxynitride tunneling films, leading to better storage capabilities compared to conventional memory structures.
Implementation Method 1
A second silicon oxynitride tunneling film is formed by performing an oxidation process applying a free radical to the first silicon oxynitride tunneling film
Data Source
AI summary
A memory structure and a manufacturing method for the same are provided. The memory structure includes a charge trapping layer, a first silicon oxynitride tunneling film and a second silicon oxynitride tunneling film. The first silicon oxynitride tunneling film is between the charge trapping layer and the second silicon oxynitride tunneling film. A first atom concentration ratio of a concentration of a nitrogen atom to a total concentration of an oxygen atom and the nitrogen atom of the first silicon oxynitride tunneling film is 10% to 50%. A second atom concentration ratio of a concentration of a nitrogen atom to a total concentration of an oxygen atom and the nitrogen atom of the second silicon oxynitride tunneling film is 1% to 15%. The concentration of the nitrogen atom of the second silicon oxynitride tunneling film is lower than that of the first silicon oxynitride tunneling film.