Gate formation scheme for nanosheet transistors having different work function metals and different nanosheet width dimensions

Patent metadata

Field	Value
Publication number	US-10692873-B2
Application number	US-201916515708-A
Country	US
Kind code	B2
Filing date	Jul 18, 2019
Priority date	Jun 27, 2018
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

Embodiments of the invention are directed to a configuration of nanosheet FET devices formed on a substrate. A non-limiting example of the nanosheet FET devices includes a first nanosheet FET having a first channel nanosheet, a second channel nanosheet over the first nanosheet, a first gate structure around the first channel nanosheet, and a second gate structure around the second channel nanosheet, wherein a first air gap is between the first gate structure and the second gate structure. The nanosheet FET devices further include a second nanosheet FET having a third channel nanosheet, a fourth channel nanosheet over the third nanosheet, a third gate structure around the third channel nanosheet, and a fourth gate structure around the fourth channel nanosheet, wherein a second air gap is between the third gate structure and the fourth gate structure.

First claim

What is claimed is:

1. A configuration of nanosheet field effect transistor (FET) devices formed on a substrate, the nanosheet FET devices comprising;
a first nanosheet FET comprising:
a first channel nanosheet;
a second channel nanosheet over the first channel nanosheet;
a first gate structure around the first channel nanosheet; and
a second gate structure around the second channel nanosheet, wherein a first air gap is between the first gate structure and the second gate structure.

2. The devices of claim 1 further comprising:
a second nanosheet FET comprising:
a third channel nanosheet;
a fourth channel nanosheet over the third channel nanosheet;
a third gate structure around the third channel nanosheet; and
a fourth gate structure around the fourth channel nanosheet, wherein a second air gap is between the third gate structure and the fourth gate structure.

3. The devices of claim 2 , wherein the first gate structure comprises a conformally deposited region.

4. The devices of claim 3 , wherein the first gate structure further comprises
a non-conformally deposited region.

5. The devices of claim 2 , wherein the first gate structure comprises a gate metal having a work function configured for operation in a first type of nanosheet FET that is configured to operate based on a first type of majority carrier.

6. The devices of claim 5 , wherein the second gate structure comprises the gate metal having the work function configured for operation in the first type of nanosheet FET that is configured to operate based on the first type of majority carrier.

7. The devices of claim 2 , wherein the third gate structure comprises a gate metal having a work function configured for operation in a second type of nanosheet FET configured to operate based on a second type of majority carrier.

8. The devices of claim 7 , wherein the fourth gate structure comprises the gate metal having the work function configured for operation in the second type of nanosheet FET configured to operate based on the second type of majority carrier.

9. A configuration of nanosheet field effect transistor (FET) devices formed on a substrate, the nanosheet FET devices comprising:
in a first region of the substrate:
a first channel nanosheet;
a second channel nanosheet over the first channel nanosheet;
a first gate structure around the first channel nano sheet; and
a second gate structure around the second channel nanosheet, wherein a first air gap is between the first gate structure and the second gate structure;

in a second region of the substrate:
a third channel nanosheet;
a fourth channel nanosheet over the third channel nanosheet;
a third gate structure around the third channel nanosheet;
a fourth gate structure around the fourth channel nanosheet, wherein a second air gap is between the third gate structure and the fourth gate structure.

10. The devices of claim 9 , wherein the first air gap extends along a first width dimension of the first channel nanosheet and along a second width dimension of the second channel nanosheet.

11. The devices of claim 10 , wherein the second air gap extends along a third width dimension of the third channel nanosheet and along a fourth width dimension of the fourth channel nanosheet.

12. The devices of claim 11 , wherein the first width dimension is less than the second width dimension.

13. The devices of claim 12 , wherein the third gate structure comprises:
a conformally deposited first region; and
a non-conformally deposited second region.

14. The devices of claim 13 , wherein a thickness dimension of the non-conformally deposited second region is less than a thickness dimension of the conformally deposited first region.

15. The devices of claim 14 , wherein the fourth gate structure comprises:
a conformally deposited third region; and
a non-conformally deposited fourth region.

16. The devices of claim 15 , wherein a thickness dimension of the non-conformally deposited fourth region is less than a thickness dimension of the conformally deposited third region.

17. The devices of claim 9 , wherein the first gate structure, the second gate structure, the third gate structure, and the fourth gate structure comprise a gate metal having a work function configured for operation in a first type of FET configured to operate based on a first type of majority carrier.

18. The devices of claim 17 further comprising a fifth gate structure formed around the third channel nanosheet.

19. The devices of claim 18 further comprising a sixth gate structure formed around the fourth channel nanosheet.

20. The devices of claim 19 , wherein the fifth gate structure and the sixth gate structure comprise a gate metal having a work function configured for operation in a second type of FET configured to operate based on a second type of majority carrier.

Assignees

• IBM

Inventors

• Ando Takashi
• Bao Ruqiang
• Hashemi Pouya
• Lee Choonghyun

Classifications

• H10P50/283

  by chemical means · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10P14/69433

  the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz · CPC title

• H10P50/264

  by chemical means · CPC title

• H10P14/3411

  Silicon, silicon germanium or germanium · CPC title