GAA Nanostructure Superlattice for Lower Effective Mass
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Solution Overview
Problem
Current semiconductor devices do not fully leverage advanced semiconductor materials and processing techniques to achieve optimal performance in terms of charge carrier mobility and device efficiency.
Innovation Solution
The development of a semiconductor gate-all-around (GAA) device incorporating a superlattice structure with stacked groups of layers, including non-semiconductor monolayers like oxygen and carbon within a crystal lattice of base semiconductor portions, which reduces the effective mass of charge carriers and enhances mobility, while also acting as an insulator and barrier to dopant diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor materials and structures are used, then device structure is simple and manufacturing is easier, but charge carrier mobility is limited and device performance is suboptimal
Solution Approach 1:
The channel layer is segmented into multiple thin layers (first semiconductor layer, second semiconductor layer, third semiconductor layer) with different compositions and functions. This segmentation allows each layer to be optimized for specific purposes: the first layer provides tensile strain for electron mobility enhancement, the second layer serves as the main channel, and the third layer provides compressive strain. This multi-layer segmentation resolves the contradiction by achieving superior device performance through functional division while maintaining manufacturability through standardized processing steps for each layer.
Solution Approach 2:
The patent employs composite material structures including silicon-germanium-silicon (SiGe/Si) superlattice layers combined with silicon nitride stressor layers. The SiGe/Si superlattice provides both structural support and strain engineering capabilities, while the silicon nitride layers add mechanical stress control. This composite approach enables simultaneous optimization of charge carrier mobility, structural integrity, and device performance, resolving the contradiction between performance enhancement and structural simplicity.
2Reliability
If advanced superlattice structures with multiple layers are implemented, then charge carrier mobility is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent incorporates preliminary strain engineering by pre-configuring the first semiconductor layer with tensile strain and the third semiconductor layer with compressive strain before the main channel formation. The SiGe/Si superlattice layers are prepared in advance to establish the desired strain profile. This preliminary action allows the main channel layer to inherit optimized strain characteristics, enhancing charge carrier mobility while reducing the need for complex post-processing steps.
Solution Approach 2:
The patent systematically varies material composition parameters across different layers: the first semiconductor layer has a first composition ratio, the second layer has a second composition ratio, and the third layer has a third composition ratio. These parameter changes are precisely controlled during deposition to achieve desired strain levels and mobility characteristics. By managing composition parameters rather than structural complexity, the patent enhances mobility while maintaining manufacturing feasibility through parameter optimization rather than process complexity.
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 results in higher charge carrier mobility, reduced scattering effects, and improved device performance, with potential benefits for opto-electronic devices due to the direct energy bandgap and enhanced conductivity properties.
Implementation Method 1
The at least one superlattice may include a plurality of stacked groups of layers, with each group of layers including a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions
Implementation Method 2
at least one superlattice within at least one of the nanostructures... acting as an insulator and barrier to dopant diffusion
Implementation Method 3
Electrons having a smaller effective mass, and which have been induced by an electric field applied to the gate electrode, are confined in the second silicon layer
Data Source
AI summary
A semiconductor gate-all-around (GAA) device may include a semiconductor substrate, source and drain regions on the semiconductor substrate, a plurality of semiconductor nanostructures extending between the source and drain regions, and a gate surrounding the plurality of semiconductor nanostructures in a gate-all-around arrangement. Furthermore, at least one superlattice may be within at least one of the nanostructures. The at least one superlattice may include a plurality of stacked groups of layers, with each group of layers including a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions.