GAA Transistor Nanostructure Stacking for Density and Power Trade-offs
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving high device density, performance, and cost-effectiveness due to limitations in fabrication and design, particularly in three-dimensional designs as the industry advances into nanometer technology process nodes.
Innovation Solution
The development of a gate all around (GAA) transistor structure with vertically stacked nanostructures, including silicon and silicon germanium layers, formed using selective epitaxial growth and chemical vapor deposition processes, along with specific patterning and spacer formation techniques to enhance device performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional planar semiconductor devices are used, then manufacturing is simpler, but device density and performance are limited
Solution Approach 1:
The patent transitions from conventional planar (2D) transistor structures to three-dimensional vertically stacked nanostructures. Multiple semiconductor layers are stacked vertically to form channels that extend in the vertical direction, enabling higher device density by utilizing the third dimension while maintaining manufacturability through established deposition and etching processes
2Speed
If more nanostructures are used to increase device density, then speed performance improves, but power consumption increases
Solution Approach 1:
The patent implements different dielectric layer configurations in different vertical regions of the stacked structure. The first dielectric layer is positioned at a first height and the second dielectric layer at a second height, creating locally optimized regions that can be tuned for either speed performance or power efficiency depending on the application requirements
Solution Approach 2:
The patent varies the number of effective nanostructures and their vertical positioning to optimize device characteristics. By controlling which nanostructures are electrically active and their spatial distribution, the device can be configured for high-speed operation with more nanostructures or power-efficient operation with fewer nanostructures
3Productivity
If vertically stacked nanostructures are implemented, then device density and speed improve, but parasitic capacitance increases
Solution Approach 1:
The patent introduces dielectric layers as intermediary materials between the stacked semiconductor nanostructures. These dielectric layers act as electrical isolators that reduce parasitic capacitance coupling between adjacent nanostructures while maintaining the vertical stacking configuration for high device density
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 creation of semiconductor devices with improved speed and power efficiency by controlling the effective nanostructure number and width, allowing for high-speed performance in some regions and power efficiency in others, while reducing parasitic capacitance and optimizing device layout.
Implementation Method 1
chemical vapor deposition processes
Implementation Method 2
selective epitaxial growth
Data Source
AI summary
A semiconductor device structure and method for forming the same are provided. The semiconductor device structure includes a plurality of first nanostructures stacked over a substrate in a vertical direction. The semiconductor device structure also includes a first bottom layer formed adjacent to the first nanostructures, and a first dielectric layer formed over the first bottom layer. The semiconductor device structure further includes a first source/drain (S/D) structure formed over the first dielectric layer, and the first S/D structure is isolated from the first bottom layer by the first dielectric layer.