Formation of wrap-around-contact to reduce contact resistivity
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.
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.