Forming strained channel with germanium condensation
A method for forming a semiconductor device includes forming a strained fin on a substrate, a sacrificial gate on a channel region of the fin, a first spacer adjacent to a sidewall of the fin, and a second spacer adjacent to the first spacer. A source/drain region is grown on an exposed portion of the fin. Atoms are driven from the source/drain region into the fin and form an oxide layer on the source/drain region. The second spacer and the oxide layer are removed. An insulator layer is formed over the source/drain region, and the sacrificial gate is removed to expose the channel region of the fin. A gate stack is formed over the channel region of the fin.
1. A method for forming a semiconductor device, the method comprising:
forming a strained fin on a substrate;
forming a sacrificial gate on a channel region of the fin;
forming a first spacer adjacent to a sidewall of the fin;
forming a second spacer adjacent to the first spacer;
growing a source/drain region on an exposed portion of the fin;
annealing to drive atoms from the source/drain region into the fin and form an oxide layer on the source/drain region;
removing the second spacer and the oxide layer;
forming an insulator layer over the source/drain region;
removing the sacrificial gate to expose the channel region of the fin; and
forming a gate stack over the channel region of the fin.
2. The method of claim 1 , wherein the substrate includes silicon.
3. The method of claim 1 , wherein the strained fin includes SiGe.
4. The method of claim 1 , wherein the source/drain region includes Ge.
5. The method of claim 1 , wherein the atoms are Ge atoms.
6. The method of claim 1 , wherein the annealing increases a concentration of Ge atoms in the fin.
7. The method of claim 1 , wherein the first spacer includes a nitride material and the second spacer includes an oxide material.
8. The method of claim 1 , wherein the strained fin is compressively strained.
9. The method of claim 1 , further comprising:
forming a source/drain extension region by implanting dopants in the after removing the second spacer;
removing portions of the insulator layer to expose the source/drain region; and
forming a conductive contact over the source/drain region.
10. A method for forming a semiconductor device, the method comprising:
forming a strained semiconductor layer on a substrate;
removing portions of the strained semiconductor layer to form a fin on the substrate;
depositing an insulator layer on the substrate;
forming a sacrificial gate on a channel region of the fin;
forming a first spacer adjacent to a sidewall of the fin;
forming a second spacer adjacent to the first spacer;
growing a source/drain region on an exposed portion of the fin;
annealing to drive atoms from the source/drain region into the fin and form an oxide layer on the source/drain region;
removing the second spacer and the oxide layer;
forming an insulator layer over the source/drain region;
removing the sacrificial gate to expose the channel region of the fin; and
forming a gate stack over the channel region of the fin.
11. The method of claim 10 , wherein the substrate includes silicon.
12. The method of claim 10 , wherein the strained semiconductor layer includes SiGe.
13. The method of claim 10 , wherein the source/drain region includes Ge.
14. The method of claim 10 , wherein the atoms are Ge atoms.
15. The method of claim 10 , wherein the annealing increases a concentration of Ge atoms in the fin.
16. The method of claim 10 , wherein the first spacer includes a nitride material and the second spacer includes an oxide material.
17. The method of claim 10 , wherein the strained semiconductor layer is compressively strained.
18. The method of claim 10 , further comprising:
forming a source/drain extension region by implanting dopants in the after removing the second spacer;
removing portions of the insulator layer to expose the source/drain region; and
forming a conductive contact over the source/drain region.