Semiconductor Memory Gate Insulator Metal Dot Charge Storage
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Solution Overview
Problem
Recent advancements in semiconductor technology have led to smaller memory cells with thinner gate insulating films, resulting in decreased charge storage density, which affects the difference between threshold voltages in writing and erasing states, necessitating an improvement in electric performance while maintaining reduced size.
Innovation Solution
Incorporating a gate insulating film structure with a silicon nitride film and metal dots dispersed between the silicon nitride and silicon oxide layers, where the metal dots act as additional charge storage elements, enhancing charge storage density without increasing film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gate insulating film is made thinner to reduce memory cell size, then the memory cell size is reduced, but the charge storage density decreases
Solution Approach 1:
The patent applies local quality by creating metal dots with high charge storage capability at specific locations within the gate insulating film structure. Instead of uniformly thickening the film, metal dots are locally introduced between the silicon nitride film and silicon oxide film, concentrating charge storage function in specific regions while maintaining overall thin film structure for small cell size.
Solution Approach 2:
The patent uses composite materials by combining silicon nitride film, silicon oxide film, and metal dots to form a multi-layer gate insulating film structure. This composite structure leverages the charge trapping capability of silicon nitride, the insulating properties of silicon oxide, and the high charge storage density of metal dots, achieving both small size and high charge storage density.
2Quantity of substance
If metal elements are introduced into the gate insulating film to increase charge storage density, then the charge storage density increases, but the film structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the gate insulating film into distinct functional layers: silicon nitride film for charge trapping, silicon oxide film for insulation, and metal dots for charge storage. This segmented structure allows each layer to perform its specific function efficiently while maintaining overall structural organization and manageability.
Solution Approach 2:
The patent uses the nesting principle by placing metal dots within the gate insulating film structure, specifically between the silicon nitride film and silicon oxide film. The metal dots are embedded or dispersed within the film layers, creating a nested configuration that increases charge storage density without requiring a completely separate external structure.
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 configuration increases the surface density of storable charges, maintaining a large difference in threshold voltages between writing and erasing states, thereby improving electric performance and reducing memory cell size effectively.
Implementation Method 1
Metal elements exist between the silicon nitride film and the second silicon oxide film, or in the silicon nitride film at a surface density of 1×10^13 to 2×10^14 atoms/cm²
Data Source
AI summary
A semiconductor device with a nonvolatile memory is provided which has improved electric performance. A memory gate electrode is formed over a semiconductor substrate via an insulating film. The insulating film is an insulating film having a charge storage portion therein, and includes a first silicon oxide film, a silicon nitride film over the first silicon oxide film, and a second silicon oxide film over the silicon nitride film. Metal elements exist between the silicon nitride film and the second silicon oxide film, or in the silicon nitride film at a surface density of 1×1013 to 2×1014 atoms/cm2.