Formation of wrap-around-contact to reduce contact resistivity

Patent metadata

Field	Value
Publication number	US-10886376-B2
Application number	US-201916692741-A
Country	US
Kind code	B2
Filing date	Nov 22, 2019
Priority date	Jul 3, 2018
Publication date	Jan 5, 2021
Grant date	Jan 5, 2021

Abstract

A method of forming a source/drain contact is provided. The method includes forming a sacrificial layer on a source/drain, and depositing an oxidation layer on the sacrificial layer. The method further includes heat treating the oxidation layer and the sacrificial layer to form a modified sacrificial layer. The method further includes forming a protective liner on the modified sacrificial layer, and depositing an interlayer dielectric layer on the protective liner. The method further includes forming a trench in the interlayer dielectric layer that exposes a portion of the protective liner.

First claim

What is claimed is:

1. A method of forming a source/drain contact, comprising:
forming a modified sacrificial layer on a source/drain, wherein the modified sacrificial layer is formed from a sacrificial layer and at least one other layer through a chemical reaction;
forming an interlayer dielectric (ILD) layer on the modified sacrificial layer;
removing a portion of the ILD layer located over the modified sacrificial layer to form a trench; and
removing at least a portion of the modified sacrificial layer to form a channel between the ILD layer and the source/drain that exposes at least a portion of the sidewalls of the source/drain.

2. The method of claim 1 , wherein the channel exposes a portion of the substrate adjacent to the source/drain.

3. The method of claim 1 , further comprising forming a source/drain contact in the channel.

4. The method of claim 3 , wherein the source/drain contact is a material selected from the group consisting of a metal, a conducting metallic compound material, and combinations thereof.

5. The method of claim 4 , wherein the modified sacrificial layer is silicon dioxide (SiO 2 ).

6. The method of claim 3 , wherein the source/drain contact is in direct contact with a gate sidewall spacer of a gate structure.

7. The method of claim 6 , wherein the source/drain contact is formed by atomic layer deposition (ALD).

8. The method of claim 7 , further comprising a heat treatment to form a silicide layer on the source/drain from at least a portion of the source/drain contact.

9. The method of claim 8 , wherein the source/drain contact has a contact resistivity below 3×10 −9 ohm-square centimeter to the source/drain.

10. The method of claim 8 , wherein the source/drain contact fills the trench formed in the ILD layer.

11. A method of forming a source/drain contact, comprising:
forming a modified sacrificial layer on a source/drain, wherein the modified sacrificial layer is formed from a sacrificial layer and at least one other layer through a chemical reaction;
forming a protective liner on the modified sacrificial layer;
forming an interlayer dielectric (ILD) layer on the protective liner;
removing a portion of the ILD layer located over the modified sacrificial layer to form a trench that exposes a portion of the protective liner; and
removing the exposed portion of the protective liner and at least a portion of the modified sacrificial layer to form a channel between the protective liner and the source/drain that exposes at least a portion of the sidewalls of the source/drain.

12. The method of claim 11 , further comprising depositing a protective liner extension on the exposed sidewalls of the trench, and removing the modified sacrificial layer to form a channel.

13. The method of claim 12 , further comprising forming a source/drain contact in the channel.

14. The method of claim 13 , wherein the source/drain contact is formed of a material selected from the group consisting of titanium (Ti), cobalt (Co), and nickel (Ni).

15. The method of claim 14 , wherein the modified sacrificial layer has a thickness in a range of about 2 nm to about 5 nm.

16. The method of claim 14 , wherein the protective liner has a thickness in a range of about 2 nm to about 5 nm.

17. A method of forming a source/drain contact, comprising:
forming a modified sacrificial layer on a source/drain, wherein the modified sacrificial layer is silicon dioxide (SiO 2 );
forming a protective liner on the modified sacrificial layer, wherein the protective liner is made of a material selected from the group consisting of silicon nitride (SiN) and silicon carbonitride (SiCN);
forming an interlayer dielectric (ILD) layer on the protective liner;
removing a portion of the ILD layer located over the modified sacrificial layer to form a trench that exposes a portion of the protective liner; and
removing the exposed portion of the protective liner and at least a portion of the modified sacrificial layer to form a channel between the protective liner and the source/drain that exposes at least a portion of the sidewalls of the source/drain.

18. The method of claim 17 , further comprising forming a source/drain contact in the channel.

19. The method of claim 18 , wherein the source/drain contact is formed of a material selected from the group consisting of titanium (Ti), cobalt (Co), and nickel (Ni).

20. The method of claim 18 , wherein a portion of the source/drain contact in physical contact with the source/drain has a thickness in a range of about 2 nm to about 4 nm.

Assignees

• IBM

Inventors

• Carr Adra
• Zhang Jingyun
• Lee Choonghyun
• Ando Takashi
• Hashemi Pouya

Classifications

• H10P14/418

  the conductive layers comprising transition metals · CPC title

• H10W20/0698

  Local interconnections · CPC title

• H10W20/0526

  by thermal treatment thereof · CPC title

• H10W20/083

  the openings being via holes penetrating underlying conductors · CPC title

• H10W20/081

  by forming openings in the dielectric parts · CPC title