Semiconductor device and method of forming the same

Patent metadata

Field	Value
Publication number	US-10770299-B2
Application number	US-201916726012-A
Country	US
Kind code	B2
Filing date	Dec 23, 2019
Priority date	Apr 26, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A semiconductor device includes a semiconductor fin and a gate structure. The semiconductor fin extends along a first direction above a substrate. The gate structure extends across the semiconductor fin along a second direction substantially perpendicular to the first direction. The gate structure includes a chlorine-containing N-work function metal layer wrapping around the semiconductor fin, and a filling metal over and in contact with the chlorine-containing N-work function metal layer.

First claim

What is claimed is:

1. A semiconductor device, comprising:
a semiconductor fin extending along a first direction above a substrate; and
a gate structure extending across the semiconductor fin along a second direction substantially perpendicular to the first direction, the gate structure comprising a chlorine-containing N-work function metal layer wrapping around the semiconductor fin, and a filling metal over and in contact with the chlorine-containing N-work function metal layer.

2. The semiconductor device of claim 1 , wherein the gate structure further comprises a titanium nitride layer below and in contact with the chlorine-containing N-work function metal layer.

3. The semiconductor device of claim 1 , wherein the gate structure further comprises a gate dielectric layer below and spaced from the chlorine-containing N-work function metal layer.

4. The semiconductor device of claim 1 , wherein the filling metal is tungsten.

5. The semiconductor device of claim 1 , wherein the gate structure has a minimal width at a position between topmost and bottommost positions of the gate structure.

6. The semiconductor device of claim 1 , wherein the gate structure has a maximal width at a position between topmost and bottommost positions of the gate structure.

7. The semiconductor device of claim 2 , wherein the titanium nitride layer contains carbon.

8. The semiconductor device of claim 2 , wherein the gate structure further comprises a gate dielectric layer below and in contact with the titanium nitride layer.

9. The semiconductor device of claim 8 , wherein the titanium nitride layer has a thickness less than a thickness of the gate dielectric layer.

10. The semiconductor device of claim 3 , wherein the gate dielectric layer has a thickness greater than a thickness of the chlorine-containing N-work function metal layer.

11. A semiconductor device, comprising:
a semiconductor fin protruding above a substrate;
an N-type source epitaxy structure and an N-type drain epitaxy structure on the semiconductor fin; and
a gate structure over the semiconductor fin, the gate structure comprising a high-k gate dielectric layer and a chlorine-containing N-work function metal layer spaced from the high-k gate dielectric layer and laterally between the N-type source epitaxy structure and the N-type drain epitaxy structure.

12. The semiconductor device of claim 11 , wherein the gate structure further comprises a titanium nitride layer over and in contact with the high-k gate dielectric layer, and laterally between the N-type source epitaxy structure and the N-type drain epitaxy structure.

13. The semiconductor device of claim 11 , wherein the gate structure further comprises a tungsten structure in contact with the chlorine-containing N-work function metal layer.

14. The semiconductor device of claim 12 , wherein the titanium nitride layer contains carbon.

15. A method, comprising:
forming a fin extending from a semiconductor substrate;
forming a shallow trench isolation (STI) structure laterally surrounding a lower portion of the fin;
forming a dummy gate structure across an N-type field effect transistor (NFET) channel region in the fin;
forming an N-type source epitaxy structure and an N-type drain epitaxy structure respectively on opposite sides of the NFET channel region; and
replacing the dummy gate structure with a replacement gate structure, the replacing comprising forming a titanium nitride (TiN) layer of the replacement gate structure on the NFET channel region, and a chlorine-containing N-work function metal layer of the replacement gate structure over the TiN layer on the NFET channel region.

16. The method of claim 15 , wherein the replacing further comprises forming a tungsten layer of the replacement gate structure in contact with the chlorine-containing N-work function metal layer.

17. The method of claim 15 , wherein the replacing further comprises forming a gate dielectric layer of the replacement gate structure prior to forming the TiN layer.

18. The method of claim 15 , further comprising:
forming gate spacers on either side of the dummy gate structure prior to replacing the dummy gate structure with the replacement gate structure, wherein the gate spacers define a gate trench therebetween, and the gate trench has a minimal width at a position between topmost and bottommost positions of the gate trench.

19. The method of claim 15 , further comprising:
forming gate spacers on either side of the dummy gate structure prior to replacing the dummy gate structure with the replacement gate structure, wherein the gate spacers define a gate trench therebetween, and the gate trench has a maximal width at a position between topmost and bottommost positions of the gate trench.

20. The method of claim 16 , wherein the replacing further comprises performing a chemical mechanical polish (CMP) process on the tungsten layer.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• LIU Li-Jung
• Liang Chun-Sheng
• Wang Shu-Hui

Classifications

• H10P14/43 Primary

  Chemical deposition, e.g. chemical vapour deposition [CVD] · CPC title

• H10D62/822

  comprising only Group IV materials heterojunctions, e.g. Si/Ge heterojunctions · CPC title

• H10D30/797

  being in source or drain regions, e.g. SiGe source or drain · CPC title

• H10D64/667 Primary

  the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671) · CPC title

• H10D64/518

  characterised by their lengths or sectional shapes · CPC title