Semiconductor Nanostructure Layout for Tight Pitch GAA Channels
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Solution Overview
Problem
The challenge of forming reliable semiconductor devices at smaller sizes is exacerbated by the increasing complexity of fabrication processes due to continuous scaling-down in feature sizes, which complicates processing and manufacturing.
Innovation Solution
A method involving the use of double-patterning or multi-patterning processes to create semiconductor nanostructures, such as FinFETs and gate all around (GAA) transistors, using sacrificial layers and self-aligned processes to achieve smaller pitch dimensions, combined with selective epitaxial growth and careful etching to form reliable channel structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity increases and manufacturing reliability decreases
Solution Approach 1:
The fabrication process is divided into multiple discrete stages including forming first and second semiconductor layers with different materials, selective removal of sacrificial layers, and staged deposition of gate structures. This segmentation allows each stage to be optimized independently, managing overall process complexity while achieving advanced scaling.
Solution Approach 2:
The patent transitions from planar device structures to three-dimensional FinFET and GAA transistor architectures. By adding vertical dimensions and creating multi-layer semiconductor stacks, the design achieves higher functional density without proportionally increasing lateral fabrication complexity.
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but manufacturing reliability decreases
Solution Approach 1:
Different regions of the semiconductor structure use different materials and properties optimized for specific functions. For example, silicon-germanium sacrificial layers are used in regions requiring selective etching, while silicon channels provide high mobility. This local optimization maintains reliability at scaled dimensions by ensuring each region has properties suited to its specific manufacturing challenges.
Solution Approach 2:
The process incorporates buffer layers and sacrificial structures that protect critical features during fabrication. These pre-positioned elements cushion against manufacturing variations and prevent defects from propagating, maintaining reliability even as feature sizes decrease and process windows tighten.
3Manufacturing precision
If double-patterning or multi-patterning processes are used to create semiconductor nanostructures, then pitch dimensions decrease, but process complexity increases
Solution Approach 1:
Sacrificial layers are formed and positioned in advance before the actual device structure is built. This preliminary action establishes a template that guides subsequent self-aligned deposition and etching steps, achieving precise pitch control without requiring complex real-time alignment procedures.
Solution Approach 2:
The process employs self-aligned deposition and etching where previously formed structures automatically serve as alignment references for subsequent steps. The sacrificial layers and semiconductor layers are deposited and removed in a self-organizing sequence that maintains precise pitch dimensions without additional alignment 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 enables the formation of reliable semiconductor devices with improved performance and reduced complexity by allowing for precise control over feature sizes and materials, enhancing current flow and reducing parasitic capacitance.
Implementation Method 1
a first semiconductor layer and a second semiconductor layer are grown epitaxially on the substrate
Data Source
AI summary
A semiconductor device structure and a formation method are provided. The method includes forming multiple semiconductor nanostructures and multiple semiconductor sacrificial nanostructures over a substrate. The semiconductor nanostructures and the semiconductor sacrificial nanostructures are laid out in an alternating manner. The method also includes replacing the semiconductor sacrificial nanostructures with dielectric nanostructures and forming inner spacers over side edges of the dielectric nanostructures. The method further includes forming an epitaxial structure on side edges of the semiconductor nanostructures and the inner spacers.