Method for forming different types of devices

1. A semiconductor device, comprising:

a first transistor in a first device area, the first transistor comprising:

a plurality of vertically stacked channel members,

a plurality of dielectric inner spacer features interleaving the plurality of vertically stacked channel members, and

a first gate structure wrapping around each of the plurality of vertically stacked channel members; and

a second transistor in a second device area, the second transistor comprising:

a fin-shaped channel member, and

a second gate structure over the fin-shaped channel member,

wherein the fin-shaped channel member comprises semiconductor layers interleaved by sacrificial layers,

wherein the second gate structure does not extend into the fin-shaped channel member,

wherein the semiconductor layers comprise a first semiconductor material and the sacrificial layers comprise a second semiconductor material,

wherein the first semiconductor material is different from the second semiconductor material,

wherein the plurality of vertically stacked channel members comprises the first semiconductor material.

2. The semiconductor device of claim 1 ,

wherein the first semiconductor material comprises silicon (Si), germanium (Ge), silicon germanium (SiGe), germanium tin (GeSn), silicon germanium tin (SiGeSn), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), or indium arsenide (InAs),

wherein the second semiconductor material comprises silicon (Si), germanium (Ge), silicon germanium (SiGe), germanium tin (GeSn), silicon germanium tin (SiGeSn).

3. The semiconductor device of claim 1 ,

wherein the first transistor comprises a plurality of inner spacer features disposed between the plurality of vertically stacked channel members,

wherein the second gate structure does not extend into the fin-shaped channel member.

4. The semiconductor device of claim 3 ,

wherein the first transistor further comprises a first source/drain feature,

wherein the second transistor further comprises a second source/drain feature,

wherein the first source/drain feature is in contact with the plurality of inner spacer features,

wherein the first source/drain feature is in contact with the semiconductor layers and the sacrificial layers of the fin-shaped channel member.

5. The semiconductor device of claim 1 , wherein the first device area is a logic device area and the second device area is an input/output device area.

6. The semiconductor device of claim 1 ,

wherein the first transistor comprises a first threshold voltage,

wherein the second transistor comprises a second threshold voltage different from the first threshold voltage.

7. The semiconductor device of claim 1 is a static random access memory (SRAM) cell.

8. The semiconductor device of claim 7 ,

wherein the first transistor serves as a pull-down transistor or a pass-gate transistor,

wherein the second transistor serves as a pull-up transistor.

9. A semiconductor device, comprising:

a fin-shaped channel member in a first area, the fin-shaped channel member extending along a direction;

a first gate structure directly over the fin-shaped channel member; and

a first source/drain feature,

wherein the fin-shaped channel member comprises a plurality of semiconductor layers interleaved by a plurality of sacrificial layers,

wherein the first source/drain feature directly contacts each of the plurality of semiconductor layers and each of the plurality of sacrificial layers along the direction,

wherein each of the plurality of semiconductor layers comprises a first semiconductor material and each of the plurality of sacrificial layers comprises a second semiconductor material,

wherein the first semiconductor material is different from the second semiconductor material,

wherein the first gate structure is in direct contact with sidewalls of the plurality of semiconductor layers and sidewalls of the plurality of sacrificial layers such that the first gate structure does not extend between two adjacent one of the plurality of semiconductor layers.

10. The semiconductor device of claim 9 ,

wherein the first semiconductor material comprises silicon (Si), germanium (Ge), silicon germanium (SiGe), germanium tin (GeSn), silicon germanium tin (SiGeSn), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), or indium arsenide (InAs),

wherein the second semiconductor material comprises silicon (Si), germanium (Ge), silicon germanium (SiGe), germanium tin (GeSn), silicon germanium tin (SiGeSn).

11. The semiconductor device of claim 9 , further comprising:

a plurality of vertically stacked channel members in a second area different from the first area; and

a second gate structure over and around each of the plurality of vertically stacked channel members,

wherein the plurality of vertically stacked channel members comprises the first semiconductor material.

12. The semiconductor device of claim 11 , further comprising:

a plurality of inner spacer features disposed between the plurality of vertically stacked channel members,

wherein the first gate structure does not extend into the fin-shaped channel member.

13. The semiconductor device of claim 12 , further comprising:

a second source/drain feature in contact with the plurality of vertically stacked channel members,

wherein the second source/drain feature is in contact with the plurality of inner spacer features.

14. A semiconductor structure, comprising:

a first transistor comprising:

a plurality of vertically stacked nanostructures, and

a first gate structure wrapping around each of the plurality of vertically stacked nanostructures; and

a second transistor comprising:

a fin-shaped structure, and

a second gate structure over the fin-shaped structure,

wherein the fin-shaped structure comprises first semiconductor layers interleaved by second semiconductor layers,

wherein the second gate structure does not extend between any two of the first semiconductor layers and the second semiconductor layers,

wherein a composition of the plurality of vertically stacked nanostructures is the same as a composition of the first semiconductor layers.

15. The semiconductor structure of claim 14 , wherein a composition of the second semiconductor layers is different from the composition of the first semiconductor layers.

16. The semiconductor structure of claim 14 ,

wherein the first transistor comprises a plurality of inner spacer features disposed between the plurality of vertically stacked nanostructures,

wherein the plurality of inner spacer features comprise aluminum oxide, zirconium oxide, tantalum oxide, yttrium oxide, titanium oxide, lanthanum oxide, silicon oxide, silicon carbonitride, silicon oxycarbonitride, silicon oxycarbide, or a combination thereof.

17. The semiconductor structure of claim 14 , the second gate structure is in direct contact with sidewalls of the first semiconductor layers and the second semiconductor layers.

18. The semiconductor structure of claim 14 ,

wherein the plurality of vertically stacked nanostructures comprise a top nanostructure and a bottom nanostructure,

wherein the top nanostructure comprises a first width and the bottom nanostructure comprises a second width greater than the first width.

19. The semiconductor structure of claim 18 , wherein the fin-shaped structure comprise a top width and a bottom width greater than the top width.

20. The semiconductor structure of claim 19 ,

wherein the first width is greater than the top width of the fin-shaped structure,

wherein the second width is greater than the bottom width of the fin-shaped structure.