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US 12,720,785 B2Granted
Nanosheet channel formation method and structure
AssigneeTaiwan Semicondutor Manufacturing Co.
InventorsDa-Yuan Lee, Weng Chang
Life of this patent
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Abstract
Embodiments include a nanoFET device and method for forming the same, the nanoFET having channel regions which have been thinned during a gate replacement process to remove etching residue. In some embodiments, the channel regions become dog bone shaped. In some embodiments, the ends of the channel regions have vertical protrusions or horns resulting from a previous trimming process which is performed prior to depositing sidewall spacers.
Claims20
A method comprising:
- forming first nanostructures and second nanostructures over a substrate, each of the first nanostructures alternating with each of the second nanostructures;
- forming a dummy gate structure over the first nanostructures and the second nanostructures;
- performing a first etch process to remove an upper portion of the dummy gate structure and expose the first nanostructures;
- performing a second etch process to remove the first nanostructures under the dummy gate structure, a first residue from the second etch process remaining on exposed surfaces of the second nanostructures;
- after performing the second etch process, oxidizing the first residue to form an oxidation layer;
- and
- removing the oxidation layer by a third etch process.
4 more elements
A method comprising:
- forming a stack of first nanostructures and second nanostructures over a substrate, each of the first nanostructures alternating with each of the second nanostructures;
- forming a dummy gate structure over the stack of the first nanostructures and the second nanostructures;
- forming a first recess in the stack adjacent the dummy gate structure;
- recessing sidewalls of the first nanostructures to form second recesses;
- after recessing the sidewalls of the first nanostructures, smoothing upper and lower surfaces of the second nanostructures exposed in the second recesses;
- forming a source/drain structure in the first recess;
- removing the dummy gate structure to form a third recess;
- removing the first nanostructures exposed in the third recess to form fourth recesses between adjacent ones of the second nanostructures;
- after removing the first nanostructures, smoothing upper and lower surfaces of the second nanostructures exposed in the fourth recesses;
- and
- forming a replacement gate structure in the third recess and the fourth recesses.
8 more elements
A method comprising:
- forming a nanostructure stack of a first nanostructure, a second nanostructure over the first nanostructure, and a third nanostructure over the second nanostructure;
- forming a first gate structure over the nanostructure stack;
- forming a first recess in the nanostructure stack adjacent the first gate structure;
- recessing sidewalls of the first nanostructure and the third nanostructure to expose a first upper surface and a first lower surface of the second nanostructure;
- forming a first inner spacer adjacent an end of the first nanostructure on the first lower surface of the second nanostructure and a second inner spacer adjacent an end of the third nanostructure on the first upper surface of the second nanostructure;
- forming a source/drain structure in the first recess;
- removing the first gate structure to form a second recess;
- removing the first nanostructure and the third nanostructure in the second recess;
- smoothing exposed surfaces of the second nanostructure in the second recess;
- and
- forming a replacement gate structure in the second recess, wherein the second nanostructure has a first height at a first location under the replacement gate structure, a second height at a second location adjacent the source/drain structure, and a third height at a location between the first location and the second location, wherein the third height is greater than the first height, wherein the third height is greater than the second height.
8 more elements
Dependencies are inferred from the claim text.