Reverse U-Shaped Epitaxial Layer FinFET Leakage Reduction
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Solution Overview
Problem
Current fin field effect transistor (FinFET) fabrication techniques face challenges with current leakage due to design bottlenecks, affecting the overall performance of the semiconductor device.
Innovation Solution
A method involving the formation of a fin-shaped structure on a substrate, with a first and second liner, followed by the creation of a recess and the growth of a reverse U-shaped epitaxial layer within this recess, accompanied by shallow trench isolation (STI) and spacers to enhance the channel region control and reduce leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional FinFET fabrication is used, then device scaling is achieved, but current leakage increases and performance deteriorates
Solution Approach 1:
The patent segments the channel region by introducing a reverse U-shaped epitaxial layer that divides the channel into multiple sections. This segmentation allows for better control of current flow paths and reduces leakage by creating distinct functional zones within the channel, directly addressing the current leakage issue while maintaining device performance
Solution Approach 2:
The reverse U-shaped epitaxial layer introduces local quality variations by creating regions with different electrical properties within the channel. The epitaxial layer has different doping characteristics compared to the surrounding fin structure, allowing localized control of current flow and reducing leakage in specific areas while maintaining overall device performance
2Productivity
If gate length is reduced for scaling, then device size decreases, but short channel effects increase
Solution Approach 1:
The patent transitions from a two-dimensional planar channel to a three-dimensional reverse U-shaped epitaxial structure. This dimensional change allows the channel to extend vertically and horizontally, effectively increasing the channel length without increasing the gate length footprint, thereby reducing short channel effects while maintaining scaled device dimensions
Solution Approach 2:
The reverse U-shaped epitaxial layer introduces curvature to the channel structure, creating a non-linear current path. This curved geometry increases the effective channel length and improves gate control over the channel, reducing short channel effects while maintaining compact device scaling
3Manufacturing precision
If gate and fin overlapping area is increased, then channel control improves, but fabrication complexity increases
Solution Approach 1:
The reverse U-shaped epitaxial layer is formed preliminarily before gate fabrication, establishing the channel structure in advance. This preliminary action defines the channel geometry and control regions before subsequent processing steps, simplifying the overall fabrication process while achieving precise channel control through the pre-formed epitaxial 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 approach improves the control over the channel region, reduces drain-induced barrier lowering and short channel effects, and increases current between the source and drain, thereby enhancing the performance of FinFET devices.
Implementation Method 1
an epitaxial layer is formed in the recess
Data Source
AI summary
A method for fabricating semiconductor device is disclosed. First, a fin-shaped structure is formed on a substrate, a first liner is formed on the substrate and the fin-shaped structure, a second liner is formed on the first liner, part of the second liner and part of the first liner are removed to expose a top surface of the fin-shaped structure, part of the first liner between the fin-shaped structure and the second liner is removed to form a recess, and an epitaxial layer is formed in the recess.