Strained Epitaxial Shell on Fin FET for On-Current Enhancement
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Solution Overview
Problem
Fin field effect transistors with uniform semiconductor fins lack the ability to enhance on-current per unit area and control leakage current effectively due to uniform material properties, which restricts the optimization of channel material properties.
Innovation Solution
A semiconductor fin with a strained epitaxial semiconductor shell is formed using selective epitaxy, where the shell material is lattice-mismatched with the fin material, allowing for bilaterally strained channels and altered source and drain region properties, enabling increased dopant incorporation and improved metallization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a uniform semiconductor material is used throughout the fin, then the manufacturing process is simple, but the on-current per unit area cannot be enhanced and leakage current cannot be controlled effectively
Solution Approach 1:
The fin structure is segmented into two distinct material regions: a core semiconductor material and an epitaxial semiconductor shell. This segmentation allows different material properties to be assigned to different regions, enabling enhanced on-current through the strained shell while maintaining simple manufacturing of the uniform core.
Solution Approach 2:
The epitaxial semiconductor shell is applied locally on the sidewalls of the fin, creating a non-uniform structure with localized strain. This local quality enhancement allows improvement of on-current per unit area specifically at the channel region without complicating the entire fin structure.
2Adaptability or versatility
If different semiconductor materials are used in the fin, then channel material properties can be optimized, but the manufacturing process becomes more complex
Solution Approach 1:
The fin structure combines two different semiconductor materials: a core material and an epitaxial shell material with different properties. This composite structure enables optimization of channel material properties through the strained shell while using a standardized manufacturing process for forming the core, balancing versatility with ease of manufacture.
3Reliability
If a strained epitaxial semiconductor shell is formed, then on-current is enhanced and off-state leakage current is reduced, but the device structure becomes more complex
Solution Approach 1:
A thin epitaxial semiconductor shell is formed on the fin sidewalls, creating a flexible strained layer that enhances carrier mobility and current control. The thin film nature of the shell minimizes structural complexity while achieving improved reliability through enhanced on-current and reduced off-state leakage.
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 strained epitaxial shell enhances on-current and reduces off-state leakage current, providing improved performance and flexibility in channel material properties for fin field effect transistors.
Implementation Method 1
A semiconductor shell including an epitaxial semiconductor material is formed on all physically exposed surfaces of the semiconductor fin by selective epitaxy, which deposits the semiconductor material only on semiconductor surfaces and not on dielectric surfaces
Implementation Method 2
The epitaxial semiconductor material can be different from the single crystalline semiconductor material, and the semiconductor shell can be bilaterally strained due to lattice mismatch
Data Source
AI summary
A semiconductor fin including a single crystalline semiconductor material is formed on a dielectric layer. A semiconductor shell including an epitaxial semiconductor material is formed on all physically exposed surfaces of the semiconductor fin by selective epitaxy, which deposits the semiconductor material only on semiconductor surfaces and not on dielectric surfaces. The epitaxial semiconductor material can be different from the single crystalline semiconductor material, and the semiconductor shell can be bilaterally strained due to lattice mismatch. A fin field effect transistor including a strained channel can be formed. Further, the semiconductor shell can advantageously alter properties of the source and drain regions, for example, by allowing incorporation of more dopants or by facilitating a metallization process.