Graphene layer for low resistance contacts and damascene interconnects
The present disclosure provides low resistance contacts and damascene interconnects with one or more graphene layers in fin structures of FETs. An example semiconductor device can include a substrate with a fin structure that includes an epitaxial region. The semiconductor device can also include an etch stop layer on the epitaxial region, and an interlayer dielectric layer on the etch stop layer. The semiconductor device can further include a metal contact, above the epitaxial region, formed through the etch stop layer and the interlayer dielectric layer, and a graphene film at interfaces between the metal contact and each of the epitaxial region, the etch stop layer, and the interlayer dielectric layer.
1. A method of forming a semiconductor device, comprising:
forming a fin structure with an epitaxial layer;
forming a catalyst layer in an opening that exposes a top surface of the epitaxial layer;
forming a graphene film at an interface between the catalyst layer and the epitaxial layer; and
forming a metal plug on the graphene film to fill the opening.
2. The method of claim 1 , further comprising:
prior to forming the metal plug, removing the catalyst layer.
3. The method of claim 1 , wherein:
forming the catalyst layer comprises depositing a first metal; and
forming the metal plug comprises depositing a second metal different from the first metal.
4. The method of claim 1 , wherein:
forming the catalyst layer comprises depositing a first metal; and
forming the metal plug comprises depositing the first metal on the catalyst layer, wherein the catalyst layer is used as a seeding layer.
5. The method of claim 1 , wherein:
forming the catalyst layer comprises depositing a first metal; and
forming the metal plug comprises depositing a second metal on the catalyst layer, wherein the catalyst layer is used as a seeding layer and the second metal is different from the first metal.
6. A method of forming a semiconductor device, comprising:
forming a fin structure with an epitaxial layer;
forming a graphene seeding layer in an opening that exposes a top surface of the epitaxial layer;
forming a graphene film by heating the graphene seeding layer to drive precipitation and growth of carbon atoms in the graphene seeding layer; and
forming a metal plug on the graphene film to fill the opening.
7. The method of claim 6 , wherein forming the graphene seeding layer comprises using 1,2,3,4-tetraphenylnaphthalene, Pyrene, or Benzene as a carbon source.
8. The method of claim 6 , wherein forming the graphene film comprises heating the graphene seeding layer by one of an ultraviolet curing process, a laser treatment process, and a thermal anneal process.
9. The method of claim 6 , wherein forming the metal plug comprises:
depositing a metal in the opening; and
performing an activation annealing process at a temperature between about 380° C. and about 450° C. in argon or a vacuum.
10. The method of claim 6 , further comprising:
prior to forming the graphene seeding layer, forming an epitaxial termination interface by treating the top surface of the epitaxial layer.
11. The method of claim 1 , wherein forming the graphene film comprises flowing acetylene over the catalyst layer to form a layer of carbon atoms on the catalyst layer.
12. The method of claim 11 , further comprising annealing the layer of carbon atoms at a temperature between about 400° ° C. and about 450° ° C.
13. The method of claim 1 , further comprising removing the catalyst layer outside the opening using a chemical mechanical polishing process.
14. The method of claim 1 , further comprising forming the graphene film with a thickness between about 0.3 nm and about 5 nm.
15. The method of claim 6 , further comprising removing the graphene film and the graphene seeding layer outside the opening using a chemical mechanical polishing process.
16. The method of claim 6 , further comprising forming the graphene layer at an interface between the metal plug and epitaxial layer.
17. A method, comprising:
forming, on a substrate, a fin structure comprising an epitaxial region;
forming an etch stop layer on the epitaxial region;
forming an interlayer dielectric layer on the etch stop layer;
forming an opening in the interlayer dielectric and the etch stop layer;
forming a retentive catalyst layer within the opening; and
forming a graphene layer at an interface of the retentive catalyst layer and the epitaxial region.
18. The method of claim 17 , further comprising forming a metal contact on the retentive catalyst layer.
19. The method of claim 18 , further comprising forming the retentive catalyst layer and the metal contact with the same material.
20. The method of claim 17 , wherein forming the retentive catalyst layer comprises forming the retentive catalyst layer on a bottom surface and sidewalls of the opening.