Non-planar field effect transistor devices with wrap-around source/drain contacts
Non-planar field effect transistor (FET) devices having wrap-around source/drain contacts are provided, as well as methods for fabricating non-planar FET devices with wrap-around source/drain contacts. A method includes forming a non-planar FET device on a substrate, which includes a semiconductor channel layer, and a gate structure in contact with upper and sidewall surfaces of the semiconductor channel layer. First and second source/drain regions are formed on opposite sides of the gate structure in contact with the semiconductor channel layer. First and second recesses are formed in an isolation layer below bottom surfaces of the first and second source/drain regions, respectively. A layer of metallic material is deposited to fill the first and second recesses in the isolation layer with metallic material and form first and second source/drain contacts which surround the first and second source/drain regions.
1. A semiconductor integrated circuit device, comprising:
a non-planar field effect transistor (FET) device disposed on a semiconductor substrate, wherein the non-planar FET device comprises a semiconductor channel layer, and a gate structure in contact with at least an upper surface and sidewall surfaces of the semiconductor channel layer;
a first epitaxial source/drain layer disposed adjacent to a first side of the gate structure and in contact with a first end of the semiconductor channel layer exposed through a gate sidewall spacer of the gate structure;
a second epitaxial source/drain layer disposed adjacent to a second side of the gate structure, opposite the first side of the gate structure, and in contact with a second end of the semiconductor channel layer exposed through the gate sidewall spacer of the gate structure;
a first recess formed in an isolation layer below a bottom surface of the first epitaxial source/drain layer;
a second recess formed in the isolation layer below a bottom surface of the second epitaxial source/drain layer;
a first source/drain contact formed in contact with an upper surface, sidewalls surfaces, and the bottom surface of the first epitaxial source/drain layer, wherein the first source/drain contact comprises metallic material that is disposed within the first recess in the isolation layer to make contact with the bottom surface of the first epitaxial source/drain layer; and
a second source/drain contact formed in contact with an upper surface, sidewalls surfaces, and the bottom surface of the second epitaxial source/drain layer, wherein the second source/drain contact comprises metallic material that is disposed within the second recess in the isolation layer to make contact with the bottom surface of the second epitaxial source/drain layer.
2. The device of claim 1 , wherein the non-planar FET device comprises a nanowire FET device, wherein the semiconductor channel layer comprises at least one semiconductor nanowire that is encapsulated within the gate structure.
3. The device of claim 1 , wherein the non-planar FET device comprises a nanosheet FET device, wherein the semiconductor channel layer comprises at least one semiconductor nanosheet layer that is encapsulated within the gate structure.
4. The device of claim 1 , wherein the non-planar FET device comprises a FinFET, wherein the semiconductor channel layer comprises at least one vertical semiconductor fin, wherein the gate structure is formed over a portion of the vertical semiconductor fin, and wherein the first and second epitaxial source/drain layers are formed on portions of the vertical semiconductor fin which extend from the gate sidewall spacer of the gate structure.
5. The device of claim 1 , wherein the first and second epitaxial source/drain layers are grown on the first and second ends of the semiconductor channel layer.
6. The device of claim 1 , wherein the gate structure comprises a high-k metal gate structure comprising a conformal high-k gate dielectric layer formed on surfaces of the semiconductor channel layer, and a metallic gate electrode layer.
7. The device of claim 1 , wherein the isolation layer isolates the first and second source/drain contacts from the semiconductor substrate.
8. The device of claim 1 , wherein the isolation layer comprises a footprint area that is substantially similar to a footprint area of the semiconductor channel layer.
9. The device of claim 1 , further comprising a shallow trench isolation layer disposed around the isolation layer.
10. The device of claim 9 , wherein the shallow trench isolation layer and the isolation layer are formed of an oxide material.
11. A semiconductor integrated circuit device, comprising:
a nanowire field effect transistor (FET) device formed on a semiconductor substrate, wherein the nanowire FET device comprises a stack of nanowire channel layers, and a gate structure disposed around and in contact with the stack of nanowire channel layers;
a first epitaxial source/drain layer disposed adjacent to a first side of the gate structure and in contact with first end portions of the nanowire channel layers exposed through a gate sidewall spacer of the gate structure;
a second epitaxial source/drain layer disposed adjacent to a second side of the gate structure, opposite the first side of the gate structure, and in contact with second end portions of the nanowire channel layers exposed through the gate sidewall spacer of the gate structure;
an isolation layer disposed in the semiconductor substrate below the stack of nanowire channel layers;
a first recess formed in the isolation layer below a bottom surface of the first epitaxial source/drain layer;
a second recess formed in the isolation layer below a bottom surface of the second epitaxial source/drain layer;
a first source/drain contact formed in contact with an upper surface, sidewalls surfaces, and the bottom surface of the first epitaxial source/drain layer, wherein the first source/drain contact comprises metallic material that is disposed within the first recess in the isolation layer to make contact with the bottom surface of the first epitaxial source/drain layer; and
a second source/drain contact formed in contact with an upper surface, sidewalls surfaces, and the bottom surface of the second epitaxial source/drain layer, wherein the second source/drain contact comprises metallic material that is disposed within the second recess in the isolation layer to make contact with the bottom surface of the second epitaxial source/drain layer.
12. The device of claim 11 , wherein the first and epitaxial source/drain layers are grown on the first and second end portions of the nanowire channel layers.
13. The device of claim 11 , wherein the gate structure comprises a high-k metal gate structure comprising a conformal high-k gate dielectric layer formed on surfaces of the semiconductor channel layer, and a metallic gate electrode layer.
14. The device of claim 11 , wherein the isolation layer isolates the first and second source/drain contacts from the semiconductor substrate.
15. The device of claim 11 , wherein the isolation layer comprises a footprint area that is substantially similar to a footprint area of the stack of nanowire channel layers.
16. The device of claim 11 , further comprising a shallow trench isolation layer disposed around the isolation layer.
17. The device of claim 16 , wherein the shallow trench isolation layer and the isolation layer are formed of an oxide material.
18. A semiconductor integrated circuit device, comprising:
a nanosheet field effect transistor (FET) device formed on a semiconductor substrate, wherein the nanosheet FET device comprises a stack of nanosheet channel layers, and a gate structure disposed around and in contact with the stack of nanosheet channel layers;
a first epitaxial source/drain layer disposed adjacent to a first side of the gate structure and in contact with first end portions of the nanosheet channel layers exposed through a gate sidewall spacer of the gate structure;
a second epitaxial source/drain layer disposed adjacent to a second side of the gate structure, opposite the first side of the gate structure, and in contact with second end portions of the nanosheet channel layers exposed through the gate sidewall spacer of the gate structure;
an isolation layer disposed in the semiconductor substrate below the stack of nanosheet channel layers;
a first recess formed in the isolation layer below a bottom surface of the first epitaxial source/drain layer;
a second recess formed in the isolation layer below a bottom surface of the second epitaxial source/drain layer;
a first source/drain contact formed in contact with an upper surface, sidewalls surfaces, and the bottom surface of the first epitaxial source/drain layer, wherein the first source/drain contact comprises metallic material that is disposed within the first recess in the isolation layer to make contact with the bottom surface of the first epitaxial source/drain layer; and
a second source/drain contact formed in contact with an upper surface, sidewalls surfaces, and the bottom surface of the second epitaxial source/drain layer, wherein the second source/drain contact comprises metallic material that is disposed within the second recess in the isolation layer to make contact with the bottom surface of the second epitaxial source/drain layer.
19. The device of claim 18 , wherein:
the first and second epitaxial source/drain layers are grown on the first and second end portions of the nanosheet channel layers; and
the gate structure comprises a high-k metal gate structure comprising a conformal high-k gate dielectric layer formed on surfaces of the semiconductor channel layer, and a metallic gate electrode layer.
20. The device of claim 18 , further comprising a shallow trench isolation layer disposed around the isolation layer;
wherein the isolation layer isolates the first and second source/drain contacts from the semiconductor substrate; and
wherein the isolation layer comprises a footprint area that is substantially similar to a footprint area of the stack of nanowire channel layers.