Dielectric Fin Structure With Carbon Gradient for GAA Gate Control
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Solution Overview
Problem
The integration of gate-all-around (GAA) transistors in semiconductor manufacturing is challenging due to complexity in fabricating the gate structure around nanowires, requiring improved methods to enhance gate control and reduce short-channel effects while maintaining scalability.
Innovation Solution
A semiconductor structure is developed with a dielectric fin structure comprising a lining layer with varying carbon concentration, providing etching resistance on one side and oxidation resistance on the other, and a fill layer nested within the lining layer, which enlarges process windows and increases manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional GAA fabrication methods are used, then gate control is improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the dielectric material into multiple layers with different carbon concentrations. The first dielectric layer has higher carbon concentration for etching resistance, while the second dielectric layer has lower carbon concentration for oxidation resistance. This segmentation allows each layer to perform its specific function optimally, improving gate control while managing fabrication complexity through specialized functional layers.
Solution Approach 2:
Different regions of the dielectric structure are assigned different carbon concentrations based on their specific functional requirements. The inner dielectric layer near the nanowire interface has higher carbon concentration to resist etching during gate formation, while the outer dielectric layer has lower carbon concentration to resist oxidation during subsequent processing. This local quality differentiation resolves the contradiction by optimizing each region for its specific purpose.
2Ease of manufacture
If dielectric layers with uniform composition are used, then manufacturing process is simple, but process window is limited
Solution Approach 1:
The patent changes the carbon concentration parameter within the dielectric layers to optimize process windows. By incorporating a first dielectric layer with higher carbon concentration and a second dielectric layer with lower carbon concentration, the structure achieves both etching resistance and oxidation resistance, thereby enlarging the manufacturing process window while maintaining reasonable fabrication complexity.
Solution Approach 2:
The patent uses composite dielectric structures with varying carbon concentrations to achieve superior performance. The combination of high-carbon dielectric material for etching resistance and low-carbon dielectric material for oxidation resistance creates a composite structure that enlarges the process window, resolving the contradiction between manufacturing simplicity and manufacturing precision.
3Strength
If carbon concentration is increased in dielectric layer, then etching resistance is improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent segments the dielectric structure into two distinct layers with different carbon concentrations. The first dielectric layer contains a first concentration of carbon providing etching resistance, while the second dielectric layer contains a second concentration of carbon providing oxidation resistance. This segmentation resolves the contradiction by assigning opposite properties to different layers rather than attempting to achieve both properties in a single uniform layer.
Solution Approach 2:
Different carbon concentrations are applied locally to different dielectric layers based on their specific protective functions. The inner dielectric layer has higher carbon concentration localized for etching resistance, while the outer dielectric layer has lower carbon concentration localized for oxidation resistance, thereby resolving the contradiction through spatial differentiation of material properties.
4Productivity
If miniaturization is pursued, then production efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the dielectric structure into multiple functional layers with different carbon concentrations. This allows each layer to be optimized for specific functions (etching resistance, oxidation resistance), enabling precise control in miniaturized GAA devices while managing manufacturing complexity through specialized functional decomposition.
Solution Approach 2:
By changing the carbon concentration parameter in different dielectric layers, the patent achieves precise control over etching and oxidation behaviors in miniaturized structures. This parameter differentiation enables improved production efficiency through better process control while managing manufacturing complexity through systematic material property optimization.
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 structure enhances manufacturing efficiency by improving etching and oxidation resistance, allowing for better control of gate structures and reducing short-channel effects, thereby supporting the production of high-performance semiconductor devices.
Implementation Method 1
The carbon concentration of the lining layer varies, e.g., the carbon concentration may decrease from a first side facing the source/drain feature toward a second side facing the fill layer. As a result, the lining layer may exhibit a good etching resistance on the first side and a good oxidation resistance on the second side.
Implementation Method 2
the lining layer may exhibit a good etching resistance on the first side and a good oxidation resistance on the second side
Data Source
AI summary
A semiconductor structure and a method of forming is provided. The semiconductor structure includes nanostructures separated from one another and stacked over a substrate, a gate stack wrapping around the nanostructures, and a dielectric fin structure laterally spaced apart from the nanostructures by the gate stack. The dielectric fin structure include a lining layer and a fill layer nested within the lining layer. The lining layer is made of a carbon-containing dielectric material, and a carbon concentration of the lining layer varies in a direction from the gate stack to the lining layer.