Dielectric Nanostructure Layout for Reliable GAA Nanosheet Scaling
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Solution Overview
Problem
The challenge of forming reliable semiconductor devices at smaller sizes is exacerbated by the increasing complexity and difficulty of fabrication processes as feature sizes continue to decrease.
Innovation Solution
The formation of semiconductor devices involves the use of nanostructure transistors, such as nanosheet transistors, patterned through methods like photolithography and self-aligned processes, with gate all around (GAA) structures, and the incorporation of dielectric nanostructures to enhance device reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple self-aligned steps including forming first and second trenches at different depths, selective epitaxial growth in specific regions, and staged doping processes. This segmentation allows complex device structures to be built through manageable, sequential steps that maintain precision while enabling scaling to smaller feature sizes
Solution Approach 2:
Shallow trench isolation structures are formed in advance before main device fabrication, and sacrificial layers are deposited and patterned beforehand to guide subsequent self-aligned processing. These preliminary actions establish the geometric framework that enables precise alignment in later steps, reducing overall process complexity despite small feature dimensions
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but device reliability becomes more difficult to ensure
Solution Approach 1:
Different regions of the device are given different properties: lightly-doped and heavily-doped semiconductor regions are created in specific zones, shallow trench isolation is applied at particular locations, and selective epitaxial growth occurs only in designated areas. This local differentiation allows the device to maintain reliability through optimized electrical characteristics in critical regions while enabling overall scaling
Solution Approach 2:
Shallow trench isolation structures are formed beforehand to provide mechanical and electrical support, and carefully controlled doping profiles are established in advance to create buffer regions that prevent defect propagation. These cushioning structures compensate for the increased stress and variability inherent in smaller feature sizes, maintaining device reliability
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a substrate. The semiconductor device structure includes a channel nanostructure and a dielectric nanostructure over the substrate. The dielectric nanostructure is between the substrate and the channel nanostructure. The semiconductor device structure includes a gate cut structure passing through the channel nanostructure and the dielectric nanostructure. The semiconductor device structure includes a first source/drain structure over the substrate and connected to the channel nanostructure. The inner spacer is between the first source/drain structure and the dielectric nanostructure.