GAA Transistor Structure Reducing Parasitic Capacitance
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Solution Overview
Problem
As feature sizes in semiconductor devices continue to decrease, the complexity of fabrication processes increases, making it challenging to form reliable semiconductor devices.
Innovation Solution
The process involves forming a gate all around (GAA) transistor structure, where nanostructures are patterned using photolithography and self-aligned processes, and spacer structures are formed to pattern the GAA structure. Additionally, source/drain structures and a dielectric layer are formed, and the nanostructures are removed to increase the distance between the gate stack and the nanostructures, reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are decreased to increase functional density, then productivity and production efficiency are improved, but manufacturing precision and fabrication complexity worsen
Solution Approach 1:
The patent segments the gate structure into multiple components including a gate electrode, gate dielectric layer, and spacer structures. This segmentation allows each component to be optimized and fabricated separately, enabling precise control over each element's dimensions and properties while maintaining overall device functionality at scaled dimensions.
Solution Approach 2:
The patent employs nested structures where spacer structures surround the gate electrode, and gate dielectric layers are positioned between the gate electrode and channel regions. This nesting approach allows multiple functional layers to be integrated in a compact arrangement, achieving high functional density while maintaining manufacturing precision through self-aligned fabrication processes.
2Productivity
If feature sizes are decreased to increase functional density, then productivity is improved, but device reliability worsens
Solution Approach 1:
The patent applies local quality by introducing spacer structures with specific materials and dimensions at critical locations around the gate electrode. These spacers provide localized electrical isolation and mechanical support where needed, enhancing device reliability at scaled dimensions without compromising overall production efficiency.
Solution Approach 2:
The patent employs preliminary action through self-aligned fabrication processes where spacer structures are formed conformally around the gate electrode before subsequent patterning steps. This preliminary formation of structural elements with precise alignment ensures reliable device operation while maintaining manufacturing efficiency through reduced alignment complexity.
3Productivity
If gate stack and nanostructures are positioned closer to increase functional density, then productivity is improved, but parasitic capacitance increases reducing performance
Solution Approach 1:
The patent introduces spacer structures as intermediary elements positioned between the gate electrode and adjacent nanostructures or channel regions. These spacers act as mediators that provide electrical isolation, reducing parasitic capacitance while allowing the gate stack and nanostructures to be positioned in close proximity for high functional density.
Solution Approach 2:
The patent addresses parasitic capacitance by transitioning from two-dimensional planar separation to three-dimensional spatial arrangement. Spacer structures extend vertically and laterally around the gate electrode, creating multi-dimensional separation that reduces capacitive coupling while maintaining compact device footprint for high functional density.
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a substrate. The semiconductor device structure includes a first nanostructure over the substrate. The semiconductor device structure includes a gate stack over the substrate and surrounding the first nanostructure. The semiconductor device structure includes a first source/drain structure and a second source/drain structure over the substrate. The gate stack is between the first source/drain structure and the second source/drain structure. The semiconductor device structure includes an inner spacer layer covering a sidewall of the first source/drain structure and partially between the gate stack and the first source/drain structure. The first nanostructure passes through the inner spacer layer. The semiconductor device structure includes a dielectric structure over the gate stack and extending into the inner spacer layer. The dielectric structure covers a top surface, an inner wall, and a lower surface of the inner spacer layer.