Nanosheet transitor with optimized junction and cladding defectivity control
A substrate structure having a set of nanosheet layers and a set of sacrificial layers stacked upon a substrate is received and a dummy gate is formed upon the nanosheet layers and the sacrificial layers. A portion of a subset of the set of sacrificial layers and a subset of the set of nanosheet layers is etched. A portion of a subset of the subset of sacrificial layers is etched to create divots within the sacrificial layers. A divot fill layer is deposited. The divot fill layer is etched to form an inner spacer between the nanosheet layers. A source/drain region is formed adjacent to the nanosheet layers and the divots. A remaining portion of the subset of the sacrificial layers is removed. The subset of the nanosheet layers is etched to a desired channel thickness producing faceted surfaces between the subset of nanosheet layers and the inner spacer.
1. A computer usable program product comprising one or more computer-readable storage devices, and program instructions stored on at least one of the one or more storage devices, the storage program instructions comprising:
program instructions to receive a substrate structure having a set of nanosheet layers and a set of sacrificial layers stacked upon a substrate;
program instructions to form a dummy gate upon the stacked set of nanosheet layers and the set of sacrificial layers;
program instructions to etch a portion of a subset of the set of sacrificial layers and a subset of the set of nanosheet layers;
program instructions to etch a portion of a subset of the subset of sacrificial layers to create divots within the subset of the subset of sacrificial layers;
program instructions to deposit a divot fill layer upon the subset of the set of sacrificial layers and the subset of the set of nanosheet layers to fill the divots;
program instructions to etch the divot fill layer to form an inner spacer between the subset of the set of nanosheet layers;
program instructions to form a source/drain (S/D) region adjacent to the subset of nanosheet layers and the divots;
program instructions to remove a remaining portion of the subset of the set of sacrificial layers; and
program instructions to etch the subset of the set of nanosheet layers to a desired channel thickness, thereby producing faceted surfaces between the subset of the set of nanosheet layers and the inner spacer,
wherein a thickness of the subset of the set of nanosheet layers is reduced to the desired channel thickness to produce the faceted surfaces and increase a separation between the subset of the set of nanosheet layers and the inner spacer.
2. The computer usable program product of claim 1 , further comprising:
program instructions to form a cladding layer upon at least one surface of the subset of the set of nanosheet layers.
3. The computer usable program product of claim 2 , wherein the faceted surfaces are (1 1 1) plane silicon crystal lattice oriented surfaces in which a growth rate of cladding material is less than that of a (1 0 0) plane silicon surface of the at least one surface of the subset of the set of nanosheet layers.
4. The computer usable program product of claim 1 , further comprising:
program instructions to form a hard mask over the dummy gate.
5. The computer usable program product of claim 4 , further comprising:
program instructions to remove a portion of the hard mask to expose an upper surface of the dummy gate; and
program instructions to remove the dummy gate.
6. The computer usable program product of claim 4 , wherein the subset of the set of sacrificial layers and the subset of the set of nanosheet layers are etched to be substantially aligned to one or more sides of the hard mask.
7. The computer usable program product of claim 1 , wherein the set of nanosheet layers and the set of sacrificial layers are stacked upon an isolation layer, and wherein the isolation layer is disposed upon the substrate.
8. The computer usable program product of claim 1 , further comprising:
program instructions to deposit a gate material.
9. The computer usable program product of claim 8 , further comprising:
program instructions to form a self-aligned contact (SAC) cap upon the gate material.
10. The computer usable program product of claim 8 , further comprising:
program instructions to form metal contacts to the S/D region and the gate material.
11. The computer usable program product of claim 1 , wherein the set of nanosheet layers are formed of silicon (Si) material.
12. The computer usable program product of claim 1 , wherein the set of sacrificial layers are formed of a silicon-germanium (SiGe) material.
13. The computer usable program product of claim 1 , wherein the divot fill layer is formed of a silicon nitride (SiN) material.
14. The computer usable program product of claim 1 , wherein the computer usable code is stored in a computer readable storage device in a data processing system, and wherein the computer usable code is transferred over a network from a remote data processing system.
15. The computer usable program product of claim 1 , wherein the computer usable code is stored in a computer readable storage device in a server data processing system, and wherein the computer usable code is downloaded over a network in a remote data processing system for use in a computer readable storage device associated with the remote data processing system.
16. A computer system comprising one or more processors, one or more computer-readable memories, and one or more computer-readable storage devices, and program instructions stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, the storage program instructions comprising:
program instructions to receive a substrate structure having a set of nanosheet layers and a set of sacrificial layers stacked upon a substrate;
program instructions to form a dummy gate upon the stacked set of nanosheet layers and the set of sacrificial layers;
program instructions to etch a portion of a subset of the set of sacrificial layers and a subset of the set of nanosheet layers;
program instructions to etch a portion of a subset of the subset of sacrificial layers to create divots within the subset of the subset of sacrificial layers;
program instructions to deposit a divot fill layer upon the subset of the set of sacrificial layers and the subset of the set of nanosheet layers to fill the divots;
program instructions to etch the divot fill layer to form an inner spacer between the subset of the set of nanosheet layers;
program instructions to form a source/drain (S/D) region adjacent to the subset of nanosheet layers and the divots;
program instructions to remove a remaining portion of the subset of the set of sacrificial layers; and
program instructions to etch the subset of the set of nanosheet layers to a desired channel thickness, thereby producing faceted surfaces between the subset of the set of nanosheet layers and the inner spacer,
wherein a thickness of the subset of the set of nanosheet layers is reduced to the desired channel thickness to produce the faceted surfaces and increase a separation between the subset of the set of nanosheet layers and the inner spacer.
17. The computer system of claim 16 , further comprising:
program instructions to form a cladding layer upon at least one surface of the subset of the set of nanosheet layers.
18. The computer system of claim 17 , wherein the faceted surfaces are (1 1 1) plane silicon crystal lattice oriented surfaces in which a growth rate of cladding material is less than that of a (1 0 0) plane silicon surface of the at least one surface of the subset of the set of nanosheet layers.
19. The computer system of claim 16 , further comprising:
program instructions to form a hard mask over the dummy gate.
20. The computer system of claim 19 , further comprising:
program instructions to remove a portion of the hard mask to expose an upper surface of the dummy age; and
program instructions to remove the dummy gate.