CMOS top source/drain region doping and epitaxial growth for a vertical field effect transistor
A method includes forming a p-type field effect transistor region and an n-type field effect transistor region into a semiconductor substrate. The method implements a process flow to fabricate highly doped top source/drains with minimal lithography and etching processes. The method permits the formation of VFETs with increased functionality and reduced scaling.
1. A vertical field effect transistor comprising:
a semiconductor substrate;
a p-type field effect transistor region disposed on the semiconductor substrate, the p-type field effect transistor region including:
a p-type bottom source/drain;
one or more first vertical fins with one or more metal gates extending above the p-type bottom source/drain;
a p-type top source/drain disposed on the one or more first vertical fins; and
implanted p-type dopants;
an n-type field effect transistor region disposed on the semiconductor substrate, the n-type field effect transistor region including:
an n-type bottom source/drain;
one or more second vertical fins with one or more metal gates extending above the n-type bottom source/drain;
an n-type top source/drain disposed on the one or more second vertical fins; and
implanted n-type dopants;
a shallow trench isolation region in the semiconductor substrate between the p-type field effect transistor region and the n-type field effect transistor region; and
an interlayer dielectric disposed relative to the semiconductor substrate;
wherein at least a peripheral portion of the interlayer dielectric within the n-type field effect transistor region and disposed outward of the one or more second vertical fins and outward of the shallow trench isolation region includes p-type dopants and n-type dopants.
2. The vertical field effect transistor of claim 1 wherein the peripheral portion of the interlayer dielectric within the n-type field effect transistor region includes two different n-type dopants and two different p-type dopants.
3. The vertical field effect transistor of claim 2 wherein the two different p-type dopants of the n-type field effect transistor region includes gallium and boron respectively.
4. The vertical field effect transistor of claim 3 wherein the two different n-type dopants of the n-type field effect transistor region includes at least two of phosphorous, arsenic and antimony.
5. The vertical field effect transistor of claim 4 wherein the two different n-type dopants of the n-type field effect transistor includes phosphorous and arsenic.
6. The vertical field effect transistor of claim 1 wherein each of the p-type top source/drain and the n-type top source/drain are epitaxially grown.
7. The vertical field effect transistor of claim 1 further comprising an interlayer dielectric layer disposed on the shallow trench isolation region.
8. The vertical field effect transistor of claim 1 wherein an upper segment of the one or more second vertical fins of the n-type field effect transistor region comprises n-type dopants of a first type and wherein the n-type top source/drain of the n-type field effect transistor region comprises n-type dopants of a second-type different from the first type.
9. The vertical field effect transistor of claim 1 wherein the n-type top source/drain is at least partially surrounded by a top spacer, the top spacer includes the implanted p-type dopants and n-type dopants.
10. A semiconductor structure, which comprises:
a substrate;
a first device and a second device disposed on the substrate and separated at least in part by an insulative pillar extending from the substrate;
the first device comprising at least an nFET region including:
a bottom source/drain;
one or more vertical fins with one or more metal gates extending above the bottom source/drain;
a top source/drain disposed on the one or more vertical fins; and
an interlayer dielectric disposed about the first and second devices;
wherein at least a peripheral portion of the interlayer dielectric disposed about the first device outward of the one or more vertical fins and outward of the insulative pillar includes p-type dopants and n-type dopants.
11. The semiconductor structure of claim 10 wherein the nFET region comprises at least one p-type dopant and at least one n-type dopant within the interlayer dielectric.
12. The semiconductor structure of claim 11 wherein the nFET region comprises two different n-type dopants and two different p-type dopants.
13. The semiconductor structure of claim 12 wherein the two different p-type dopants of the nFET region includes gallium and boron respectively.
14. The semiconductor structure of claim 13 wherein the two different n-type dopants of the nFET region includes phosphorous and arsenic.
15. The semiconductor structure of claim 10 wherein an upper segment of the one or more vertical fins of the nFET region comprises n-type dopants of a first type and wherein the top source/drain comprises n-type dopants of a second-type different from the first type.
16. A semiconductor structure comprising:
a semiconductor substrate;
a p-type field effect transistor region on the semiconductor substrate, the p-type field effect transistor region including:
a p-type bottom source/drain;
one or more first vertical fins and one or more metal gates extending above the p-type bottom source/drain;
a p-type top source/drain surrounded by a top spacer disposed on the one or more first vertical fins; and
implanted p-type dopants in the p-type top source/drain; and
an n-type field effect transistor region disposed on the semiconductor substrate, the n-type field effect transistor region including:
an n-type bottom source/drain;
one or more second vertical fins and one or more metal gates extending above the n-type bottom source/drain;
an n-type top source/drain surrounded by a top spacer disposed on the one or more second vertical fins; and
implanted p-type dopants and n-type dopants in the top source/drain; and
an interlayer dielectric disposed relative to the semiconductor substrate;
a central dielectric segment disposed between the p-type field effect transistor region and the n-type field effect transistor region;
a first outer peripheral dielectric segment disposed within the p-type field effect transistor region displaced outward of the one or more first vertical fins and the central dielectric segment; and
a second outer peripheral dielectric segment disposed within the n-type field effect transistor region displaced outward of the one or more second vertical fins and the central dielectric segment;
wherein the second outer peripheral dielectric segment of the interlayer dielectric disposed within the n-type field effect transistor region includes implanted p-type dopants and n-type dopants.
17. The semiconductor structure of claim 16 wherein the n-type field effect transistor region comprises two different n-type dopants and two different p-type dopants.
18. The semiconductor structure of claim 16 wherein the n-type top source/drain is at least partially surrounded by a top spacer, the top spacer includes the implanted p-type dopants and n-type dopants.
19. The semiconductor structure of claim 16 wherein an upper segment of the one or more second vertical fins comprises n-type dopants.
20. The semiconductor structure of claim 19 wherein the upper segment of the one or more second vertical fins of the n-type field effect transistor region comprises n-type dopants of a first type and wherein the n-type top source/drain of the n-type field effect transistor region comprises n-type dopants of a second-type different from the first type.