GAA Semiconductor Structure With Spacer Removal for S/D Formation
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Solution Overview
Problem
The integration of multi-gate devices in semiconductor manufacturing is challenging due to increased complexity and the need for improved gate control and reduced short-channel effects, which current fabrication methods struggle to address effectively.
Innovation Solution
A semiconductor structure is developed with a gate-all-around (GAA) transistor design, utilizing double-patterning or multi-patterning processes to form nanostructures and gate structures, where the second gate spacer layer is selectively removed to create a larger window for source/drain (S/D) structure formation, enhancing the quality and efficiency of S/D formation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-gate devices are integrated to improve gate control and reduce short-channel effects, then device performance is improved, but fabrication complexity increases
Solution Approach 1:
The fabrication process is segmented into multiple discrete steps including forming first and second gate spacer layers at different locations, selective removal of the second gate spacer layer, and sequential formation of source/drain structures. This segmentation allows complex multi-gate device fabrication to be broken down into manageable steps that can be controlled and optimized independently.
Solution Approach 2:
The first gate spacer layer is formed in advance before the source/drain structures, and the second gate spacer layer is selectively removed to create openings. This preliminary action prepares the structure for subsequent source/drain formation, ensuring proper alignment and control before the critical doping and metallization steps.
2Productivity
If miniaturization is pursued to improve production efficiency and lower costs, then productivity is improved, but manufacturing complexity increases
Solution Approach 1:
Different regions of the device structure receive different treatments through the selective formation and removal of gate spacer layers. The first gate spacer layer remains in certain areas while the second is removed in specific locations, allowing localized control of source/drain formation. This local quality approach enables precise feature size control even as overall device dimensions are reduced for miniaturization.
3Manufacturing precision
If the second gate spacer layer is removed to create a larger window for S/D structure formation, then S/D formation quality is improved, but process complexity increases
Solution Approach 1:
The second gate spacer layer is selectively removed (taken out) from the structure to create larger windows or openings. This extraction allows improved access and formation quality for source/drain structures in critical regions, while the first gate spacer layer remains to provide necessary spacing and alignment in other areas. The selective removal targets only the portions needed for optimal S/D formation.
Data Source
AI summary
Semiconductor structures and methods for manufacturing the same are provided. The semiconductor structure includes nanostructures formed over a substrate along a first direction, and a gate structure formed over the nanostructures along a second direction. The semiconductor structure includes an S/D structure formed adjacent to the gate structure, and a plurality of inner spacer layers between the gate structure and the S/D structure. The semiconductor structure includes a hard mask layer formed on the inner spacer layers, and a top surface of the hard mask layer is higher than a top surface of the S/D structure.