FinFET conformal junction and high epi surface dopant concentration method and device
A method of forming a source/drain region with an abrupt, vertical and conformal junction and the resulting device are disclosed. Embodiments include forming a gate electrode over and perpendicular to a semiconductor fin; forming first spacers on opposite sides of the gate electrode; forming second spacers on opposite sides of the fin; forming a cavity in the fin adjacent the first spacers, between the second spacers; partially epitaxially growing source/drain regions in each cavity; implanting a first dopant into the partially grown source/drain regions with an optional RTA thereafter; epitaxially growing a remainder of the source/drain regions in the cavities, in situ doped with a second dopant; and implanting a third dopant in the source/drain regions.
1. A device comprising:
a gate electrode over and perpendicular to a semiconductor fin;
first spacers on opposite sides of the gate electrode;
second spacers on opposite sides of the fin;
an epitaxially grown source/drain region in the fin adjacent the first spacers, between the second spacers, the epitaxially grown source/drain region having a bottom portion and a top portion;
a first dopant implanted in the bottom portion;
a second dopant in situ doped in the top portion; and
a third dopant implanted in the top portion, wherein the source/drain region has an abrupt, vertical and conformal junction boundary.
2. The device according to claim 1 , wherein the bottom portion has a height of 0 to 80% of the height of the epitaxially grown source/drain region.
3. The device according to claim 1 , wherein the first dopant has a dose of 1e14 cm −3 to 1e16 cm −3 and is implanted at an energy of 1 kiloelectron Volt (keV) to 10 keV.
4. The device according to claim 1 , wherein the second dopant has a concentration of 1e19 cm −3 to 1e21 cm −3 .
5. The device according to claim 1 , wherein the third dopant has a concentration of 1e14 cm −3 to 1e16 cm −3 and is implanted at an energy of 0.5 keV to 2 keV.
6. The device according to claim 1 , wherein the epitaxially grown source/drain region comprises embedded silicon germanium (eSiGe).
7. The device according to claim 6 , wherein the first, second, and third dopants comprise boron difluoride (BF 2 ).
8. The device according to claim 1 , wherein the epitaxially grown source/drain regions comprise silicon phosphide (SiP).
9. The device according to claim 8 , wherein the first, second, and third dopants comprise arsenic.
10. A device comprising:
a gate electrode over a semiconductor fin;
first spacers on opposite sides of the gate electrode;
second spacers on opposite sides of the fin;
a source/drain region in the fin adjacent the first spacers, between the second spacers, the source/drain region having a bottom portion and a top portion;
a first dopant in the bottom portion;
a second dopant in the top portion; and
a third dopant in the top portion, wherein the source/drain region has an abrupt, vertical and conformal junction boundary.
11. The device according to claim 10 , wherein the bottom portion has a height of 0 to 80% of the height of the epitaxially grown source/drain region.
12. The device according to claim 10 , wherein the first dopant has a dose of 1e14 cm −3 to 1e16 cm −3 and is implanted at an energy of 1 kiloelectron Volt (keV) to 10 keV.
13. The device according to claim 10 , wherein the second dopant has a concentration of 1e19 cm −3 to 1e21 cm −3 .
14. The device according to claim 10 , wherein the third dopant has a concentration of 1e14 cm −3 to 1e16 cm −3 and is implanted at an energy of 0.5 keV to 2 keV.
15. The device according to claim 10 , wherein the source/drain region comprises embedded silicon germanium (eSiGe).
16. The device according to claim 15 , wherein the source/drain region is epitaxially grown.
17. The device according to claim 16 , wherein the first, second, and third dopants comprise boron difluoride (BF 2 ).
18. The device according to claim 10 , wherein the epitaxially grown source/drain regions comprise silicon phosphide (SiP).
19. The device according to claim 18 , wherein the first, second, and third dopants comprise arsenic.
20. A device comprising:
a gate electrode over and perpendicular to a semiconductor fin;
first spacers on opposite sides of the gate electrode;
second spacers on opposite sides of the fin;
an epitaxially grown source/drain region in the fin adjacent the first spacers, between the second spacers, the epitaxially grown source/drain region having a bottom portion and a top portion;
a first dopant implanted in the bottom portion, the first dopant implanted with a dose of 1e14 cm −3 to 1e16 cm −3 and at an energy of 1 kiloelectron Volt (keV) to 10 keV;
a second dopant in situ doped in the top portion, the second dopant in situ doped with a concentration of 1e19 cm −3 to 1e21 cm −3 ; and
a third dopant implanted in the top portion, the third dopant implanted with a concentration of 1e14 cm −3 to 1e16 cm −3 and at an energy of 0.5 keV to 2 keV,
wherein the source/drain region has an abrupt, vertical and conformal junction boundary.