Semiconductor device and method of forming the same

Patent metadata

Field	Value
Publication number	US-11043385-B2
Application number	US-202017013358-A
Country	US
Kind code	B2
Filing date	Sep 4, 2020
Priority date	Apr 26, 2017
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A semiconductor device includes a semiconductor fin, a gate structure, a source epitaxy structure and a drain epitaxy structure. The semiconductor fin extends along a first direction above a substrate. The gate structure extends across the semiconductor fin along a second direction different from the first direction. The gate structure includes a gate dielectric layer wrapping around the semiconductor fin and a chlorine-containing N-work function metal layer wrapping around the gate dielectric layer. The source epitaxy structure and the drain epitaxy structure are on opposite sides of the gate structure, respectively.

First claim

What is claimed is:

1. A semiconductor device, comprising:
a semiconductor fin extending along a first direction above a substrate;
a gate structure extending across the semiconductor fin along a second direction different from the first direction, the gate structure comprising a gate dielectric layer wrapping around the semiconductor fin and a chlorine-containing N-work function metal layer wrapping around the gate dielectric layer; and
a source epitaxy structure and a drain epitaxy structure on opposite sides of the gate structure, respectively.

2. The semiconductor device of claim 1 , wherein the gate structure further comprises a titanium nitride layer wrapping around the gate dielectric layer and being wrapped around by the chlorine-containing N-work function metal layer.

3. The semiconductor device of claim 1 , wherein the gate structure further comprises a tungsten structure wrapping around the chlorine-containing N-work function metal layer.

4. The semiconductor device of claim 1 , wherein the chlorine-containing N-work function metal layer is thinner than the gate dielectric layer.

5. The semiconductor device of claim 2 , wherein the titanium nitride layer is in contact with the chlorine-containing N-work function metal layer.

6. The semiconductor device of claim 2 , wherein the titanium nitride layer is in contact with the gate dielectric layer.

7. The semiconductor device of claim 2 , wherein the titanium nitride layer is carbon-containing.

8. The semiconductor device of claim 3 , wherein the tungsten structure is in contact with the chlorine-containing N-work function metal layer.

9. A semiconductor device, comprising:
a semiconductor fin protruding above a substrate;
a source epitaxy structure and a drain epitaxy structure on the semiconductor fin; and
a gate structure between the source epitaxy structure and the drain epitaxy structure, the gate structure comprising a titanium nitride layer wrapping around the semiconductor fin, and a chlorine-containing N-work function metal layer wrapping around the titanium nitride layer.

10. The semiconductor device of claim 9 , wherein the titanium nitride layer is interfaced with the chlorine-containing N-work function metal layer.

11. The semiconductor device of claim 9 , wherein the gate structure further comprises a tungsten structure over the chlorine-containing N-work function metal layer.

12. The semiconductor device of claim 9 , wherein the gate structure further comprises a gate dielectric layer wrapped around by the titanium nitride layer.

13. The semiconductor device of claim 11 , wherein the tungsten structure is interfaced with the chlorine-containing N-work function metal layer.

14. The semiconductor device of claim 11 , wherein the tungsten structure is thicker than the chlorine-containing N-work function metal layer.

15. The semiconductor device of claim 12 , wherein the gate dielectric layer is thicker than the titanium nitride layer.

16. The semiconductor device of claim 15 , wherein the gate dielectric layer is also thicker than the chlorine-containing N-work function metal layer.

17. A method, comprising:
forming a fin extending from a substrate;
forming a shallow trench isolation (STI) structure laterally surrounding a lower portion of the fin;
forming a dummy gate structure wrapping around a channel region of the fin;
forming a source epitaxy structure and a drain epitaxy structure respectively on opposite sides of the channel region of the fin; and
replacing the dummy gate structure with a replacement gate structure, the replacing comprising depositing a chlorine-containing N-work function metal layer wrapping around the channel region of the fin, and depositing a tungsten layer wrapping around the chlorine-containing N-work function metal layer.

18. The method of claim 17 , wherein the replacing further comprises depositing a titanium nitride layer wrapping around the channel region of the fin before depositing the chlorine-containing N-work function metal layer.

19. The method of claim 17 , wherein the chlorine-containing N-work function metal layer is deposited using titanium chloride or tantalum chloride as a precursor.

20. The method of claim 18 , wherein the titanium nitride layer is deposited by a plasma enhanced atomic layer deposition (PEALD) process using a carbon-containing plasma.

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