Source/drain profile for FinFET
An embodiment is a FinFET device. The FinFET device comprises a fin, a first source/drain region, a second source/drain region, and a channel region. The fin is raised above a substrate. The first source/drain region and the second source/drain region are in the fin. The channel region is laterally between the first and second source/drain regions. The channel region has facets that are not parallel and not perpendicular to a top surface of the substrate.
1. A device comprising:
a fin raised above a substrate;
a first source/drain region in the fin;
a second source/drain region in the fin;
a channel region in the fin laterally between the first and second source/drain regions, the channel region having channel facets that are not parallel and not perpendicular to a top surface of the substrate, a first channel facet of the channel facets adjoining a first etch control section and the channel region, the first etch control section being between the first source/drain region and the channel region;
a gate dielectric over the channel region;
a gate electrode over the gate dielectric, the gate electrode directly overlying an intersection of at least two of the channel facets; and
gate spacers on opposing sides of the gate electrode and gate dielectric.
2. The device of claim 1 , wherein the channel facets are between the channel region and the first and second source/drain regions.
3. The device of claim 1 , wherein the channel region further comprises:
a first sidewall between the first source/drain region and the channel region, the first sidewall having two channel facets; and
a second sidewall between the second source/drain region and the channel region, the second sidewall having two channel facets.
4. The device of claim 1 , wherein the channel facets have a substantially (iii) crystalline orientation.
5. The device of claim 1 , wherein the first source/drain region further comprises a first facet undercutting the channel region, and wherein the second source/drain region further comprises a second facet undercutting the channel region, the first and second facets being not parallel and not perpendicular to the top surface of the substrate.
6. The device of claim 5 , wherein the first and second facets diverge from each other in a direction away from the channel region.
7. The device of claim 6 , wherein the first and second facets have a (111) crystalline orientation.
8. The device of claim 1 , wherein the first etch control section has a different material composition than the channel region and the first source/drain region.
9. A device comprising:
a fin raised above a substrate;
a first source/drain region in the fin;
a second source/drain region in the fin;
a first etch control section in the fin;
a second etch control section in the fin, the first and second etch control sections being between the first and second source/drain regions; and
a channel region between the first and second etch control sections the channel region, the first etch control section, and the first source/drain region forming a first sidewall, the first sidewall having a first facet and a second facet, the first and second facets diverging from each other along a longitudinal axis of the fin in a direction away from the channel region, the channel region, the second etch control section, and the second source/drain region forming a second sidewall, the second sidewall having a third facet and a fourth facet, the third and fourth facets diverging from each other along the longitudinal axis of the fin in a direction away from the channel region.
10. The device of claim 9 , wherein the first, second, third, and fourth facets have a substantially (111) crystalline orientation.
11. The device of claim 9 , wherein the first, second, third, and fourth facets are not parallel and not perpendicular to a major surface of the substrate.
12. The device of claim 9 , wherein the first source/drain region further comprises a fifth facet undercutting the channel region, and wherein the second source/drain region further comprises a sixth facet undercutting the channel region, the fifth and sixth facets being not parallel and not perpendicular to a major surface of the substrate.
13. The device of claim 12 , wherein the fifth and sixth facets diverge from each other in a direction away from the channel region.
14. The device of claim 12 , wherein the fifth and sixth facets have a (111) crystalline orientation.
15. The device of claim 9 further comprising:
a gate structure over the channel region;
lightly doped regions in the first and second source/drain regions;
heavily doped regions in the lightly doped regions, the lightly doped regions extending between the respective facets and the respective heavily doped regions;
an etch stop layer over and adjoining each of the first and second source/drain regions and the gate structure;
an inter-layer dielectric layer over the etch stop layer; and
a plurality of contacts through the inter-layer dielectric layer, one of the plurality of contacts corresponding and electrically coupled to each of the first and second source/drain regions and the gate structure.
16. A device comprising:
a fin extending from a substrate;
a first source/drain region on the fin;
a second source/drain region on the fin;
a first etch control section on the fin; and
a channel region between the first and second source/drain regions, the channel region and the first source/drain region forming a first sidewall, the channel region and the second source/drain region forming a second sidewall, the channel region having a neck region and a non-neck region, the neck region having a first length and the non-neck region having a second length, the first length being less than the second length, the first and second lengths being measured from the first sidewall to the second sidewall, the first etch control section having a first portion above the neck region and a second portion below the neck region.
17. The device of claim 16 , wherein the first sidewall comprises a first facet and a second facet, the first and second facets diverging from each other at the neck region along a longitudinal axis of the fin in a direction away from the channel region.
18. The device of claim 17 , wherein the first and second facets are not parallel and not perpendicular to a major surface of the substrate.
19. The device of claim 17 , wherein the first and second facets have a (111) crystalline orientation.
20. The device of claim 16 , wherein the first source/drain region further comprises a third facet undercutting the channel region, the third facet being not parallel and not perpendicular to a major surface of the substrate.