Air gap spacer formation for nano-scale semiconductor devices
Semiconductor devices having air gap spacers that are formed as part of BEOL or MOL layers of the semiconductor devices are provided, as well as methods for fabricating such air gap spacers. For example, a method comprises forming a first metallic structure and a second metallic structure on a substrate, wherein the first and second metallic structures are disposed adjacent to each other with insulating material disposed between the first and second metallic structures. The insulating material is etched to form a space between the first and second metallic structures. A layer of dielectric material is deposited over the first and second metallic structures using a pinch-off deposition process to form an air gap in the space between the first and second metallic structures, wherein a portion of the air gap extends above an upper surface of at least one of the first metallic structure and the second metallic structure.
1. A semiconductor device, comprising:
a gate structure and a source/drain contact disposed adjacent to each other on a substrate;
an air gap disposed between the gate structure and the source/drain contact; and
a dielectric material disposed over the gate structure and over the air gap;
a conformal insulating liner layer comprising: (i) a first portion disposed below the air gap; (ii) a second portion disposed between the gate structure and the air gap; and (iii) a third portion disposed between the source/drain contact and the air gap, wherein:
an upper portion of the air gap is disposed above a top surface of the gate structure and below a top surface of the source/drain contact; and
a lower portion of the air gap is disposed below a bottom surface of the source/drain contact.
2. The semiconductor device of claim 1 , wherein the semiconductor device further comprises an epitaxial source/drain region, and wherein:
the source/drain contact and the epitaxial source/drain region are in contact; and
the air gap extends above and below a top surface of the epitaxial source/drain region.
3. The semiconductor device of claim 2 , wherein a portion of the air gap is between the epitaxial source/drain region and the gate structure.
4. The semiconductor device of claim 1 , wherein the conformal insulating liner layer comprises Si and N.
5. The semiconductor device of claim 1 , wherein the conformal insulating liner layer comprises a plurality of layers comprising Si and N of about 0.1 to 0.2 nm in thickness.
6. The semiconductor device of claim 1 , wherein the conformal insulating liner layer is about 1-3 nm thick.
7. The semiconductor device of claim 4 , wherein the conformal insulating liner layer is about 1-3 nm thick.
8. The semiconductor device of claim 5 , wherein the conformal insulating liner layer is about 1-3 nm thick.
9. The semiconductor device of claim 1 , wherein the conformal insulating liner layer is about 1 nm thick.
10. The semiconductor device of claim 1 , wherein the conformal insulating liner layer is about 1.5 nm thick.
11. The semiconductor device of claim 4 , wherein the conformal insulating liner layer is about 1 nm thick.
12. The semiconductor device of claim 4 , wherein the conformal insulating liner layer is about 1.5 nm thick.
13. The semiconductor device of claim 5 , wherein the conformal insulating liner layer is about 1 nm thick.
14. The semiconductor device of claim 5 , wherein the conformal insulating liner layer is about 1.5 nm thick.
15. The semiconductor device of claim 1 , wherein the conformal insulating liner layer comprises a plurality of conformal dielectric layers.
16. The semiconductor device of claim 15 , wherein the conformal insulating liner layer is about 0.5 nm-5 nm thick.
17. The semiconductor device of claim 1 , wherein the source/drain contact comprises a conformal liner layer comprising Ta adjacent to the conformal insulating liner layer.
18. The semiconductor device of claim 1 , wherein a top surface of the dielectric material and a top surface of the source/drain contact are substantially coplanar.
19. The semiconductor device of claim 1 , wherein a portion of the dielectric material is disposed between the gate structure and the source/drain contact.
20. The semiconductor device of claim 1 , wherein a semiconductor fin comprising an epitaxial source/drain region is formed on the substrate and the source/drain contact is formed on the epitaxial source/drain region.