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US 2025/0374584 A1Published application
Source/drain bottom isolation layer with voids for semiconductor devices
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChun Yi CHOU, Guan-Lin CHEN, Kuo-Cheng CHIANG, Chih-Hao WANG
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Abstract
The present disclosure describes a semiconductor device having a source/drain (S/D) bottom isolation layer with voids. The semiconductor device includes a stack of semiconductor layers on a substrate, a gate structure surrounding the stack of semiconductor layers, a S/D structure on the substrate and adjacent to the gate structure, and an isolation layer between the S/D structure and the substrate. The isolation layer encloses a void below the S/D structure.
Claims20
A semiconductor device, comprising:
- a stack of semiconductor layers on a substrate;
- a gate structure surrounding the stack of semiconductor layers;
- a source/drain (S/D) structure on the substrate and in contact with the stack of semiconductor layers;
- and
- an isolation layer between the S/D structure and the substrate, wherein the isolation layer encloses a void below the S/D structure.
2 more elements
A semiconductor device, comprising:
- a stack of semiconductor layers on a substrate;
- a gate structure surrounding the stack of semiconductor layers;
- first and second source/drain (S/D) structures on opposite sides of the gate structure, wherein the first and second S/D structures are in contact with the stack of semiconductor layers;
- and
- an isolation layer below the stack of semiconductor layers and the first and second S/D structures, wherein the isolation layer comprises a first void below the first S/D structure and a second void below the second S/D structure.
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A method, comprising:
- depositing a sacrificial semiconductor layer, a dummy semiconductor layer, and a stack of semiconductor layers on a substrate;
- forming a recess adjacent to end portions of the sacrificial semiconductor layer, the dummy semiconductor layer, and the stack of semiconductor layers;
- forming a sacrificial epitaxial structure in the recess;
- forming an epitaxial structure on the sacrificial epitaxial structure;
- removing the sacrificial semiconductor layer and the sacrificial epitaxial structure to form an opening under the dummy semiconductor layer and the epitaxial structure;
- and
- forming an isolation layer in the opening, wherein the isolation layer extends below the dummy semiconductor layer and encloses a void under the epitaxial structure.
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Dependencies are inferred from the claim text.