Silicon-germanium FinFET device with controlled junction
Embodiments of the invention include a method for forming a FinFET device and the resulting structure. A semiconductor device including a substrate, a silicon-germanium fin formed on the substrate, a dummy gate formed on the fin, and a first set of spacers formed on the exposed sidewalls of the dummy gate is provided. Xenon is implanted into the exposed portions of the fin. A second set of spacers are formed on the exposed sidewalls of the first set of spacer. A dopant is implanted into the exposed portions of the fin. The semiconductor device is thermally annealed, such that the dopants diffuse into the adjacent portions of the fin. The dummy gate is replaced with a gate structure.
1. A method for forming a FinFET device, the method comprising: providing a semiconductor device, wherein the semiconductor device is an NFET device comprising: a substrate; a fin formed on the substrate, wherein the fin comprises silicon-germanium; a dummy gate formed on the fin; and a first set of spacers formed on exposed sidewalls of the dummy gate; implanting xenon into exposed portions of the fin; forming a second set of spacers on exposed sidewalls of the first set of spacers; subsequent to forming the second set of spacers on the exposed sidewalls of the first set of spacers, implanting a dopant into exposed portions of the fin to form a doped region of the fin, wherein subsequent to implanting the dopant into the exposed portions of the fin, a region of the fin implanted with xenon is laterally adjacent to the doped region of the fin; forming a source/drain region on the fin laterally adjacent to each spacer of the second set of spacers; thermally annealing the semiconductor device, wherein thermally annealing the semiconductor device causes the dopant to diffuse into at least a first portion of the fin; and replacing the dummy gate with a gate structure.
2. The method of claim 1 , wherein the gate structure comprises a metal gate and a high-k gate dielectric layer.
3. The method of claim 1 , wherein the first portion of the fin comprises at least a portion of the fin located beneath each spacer of the first set of spacers.
4. The method of claim 1 , wherein the fin has a composition of at least 25 percent germanium.
5. The method of claim 1 , wherein implanting xenon into exposed portions of the fin comprises:
implanting the xenon into the exposed portions of the fin based on, at least, a percentage of germanium present within the fin.
6. The method of claim 1 , wherein the dopant is Antimony.
7. The method of claim 1 , further comprising:
forming an interlayer dielectric on exposed portions of the substrate and the source/drain region.
8. The method of claim 1 , wherein the substrate includes a buried oxide layer (BOX).
9. The method of claim 1 , wherein the provided semiconductor device includes an isolation layer adjacent to the substrate and the fin.
10. The method of claim 9 , further comprising:
forming a PFET device on the substrate adjacent to the NFET device; and
forming an isolation region between the NFET device and the PFET device.
11. The method of claim 1 , wherein:
the semiconductor device further comprises a PFET device separated from the NFET device by an isolation layer; and
thermally annealing the semiconductor device causes:
the NFET device to have a larger physical gate length than the PFET device; and
the NFET device and the PFET device to have equal effective gate lengths.