Gate last semiconductor structure and method for forming the same
View Patent ↗A semiconductor structure and a method for forming the same are provided. The semiconductor structure includes a substrate and a metal gate structure formed over a fin structure of the substrate. The semiconductor structure further includes a spacer formed on a sidewall of the metal gate structure and a source/drain structure formed in the fin structure. In addition, the spacer is in direct contact with the fin structure.
1. A semiconductor structure, comprising:
a substrate;
a metal gate structure formed over a fin structure of the substrate;
a spacer formed on a sidewall of the metal gate structure; and
a source/drain structure formed in the fin structure,
wherein the source/drain structure has an extending portion extending into a recess of the spacer.
2. The semiconductor structure as claimed in claim 1 , wherein the spacer has a first width and the extending portion of the source/drain structure has a second width smaller than the first width.
3. The semiconductor structure as claimed in claim 1 , wherein the spacer has a first width and the extending portion of the source/drain structure has a second width, and a ratio of the first width to the second width is in a range from 1:1 to about 30:1.
4. The semiconductor structure as claimed in claim 1 , wherein the spacer is made of silicon nitride, silicon carbide, silicon oxynitride, silicon carbon, silicon oxide, silicon hydrogen, or a combination thereof.
5. The semiconductor structure as claimed in claim 1 , wherein the source/drain structure is a strained source/drain structure.
6. The semiconductor structure as claimed in claim 1 , wherein the metal gate structure comprises a high-k dielectric layer, a work function layer, and metal gate electrode layer.
7. The semiconductor structure as claimed in claim 1 , wherein the spacer is in direct contact with the fin structure.
8. A semiconductor structure, comprising:
a substrate;
a gate structure formed over the substrate;
a spacer formed on a sidewall of the gate structure;
a source/drain structure formed in the structure,
wherein the source/drain structure has an extending portion extending into a recess of the spacer.
9. The semiconductor structure as claimed in claim 8 , wherein the extending portion of the source/drain structure extends directly under the spacer.
10. The semiconductor structure as claimed in claim 8 , wherein the spacer has a first width and the extending portion of the source/drain structure has a second width smaller than the first width.
11. The semiconductor structure as claimed in claim 8 , wherein the spacer has a first width and the extending portion of the source/drain structure has a second width, and a ratio of the first width to the second width is in a range from 1:1 to about 30:1.
12. The semiconductor structure as claimed in claim 8 , wherein the spacer is made of silicon nitride, silicon carbide, silicon oxynitride, silcon carbon, silicon oxide, silicon hydrogen, or a combination thereof.
13. The semiconductor structure as claimed in claim 8 , wherein the source/drain structure is a strained source/drain structure.
14. A semiconductor structure, comprising:
a substrate;
a gate structure formed across a fin structure over the substrate;
a spacer formed on a sidewall of the gate structure and directly contacting the fin structure; and
a source/drain structure formed in the fin structure,
wherein the source/drain structure has an extending portion extending under the spacer into a recess of the spacer.
15. The semiconductor structure as claimed in claim 14 , wherein the gate structure and the extending portion of the source/drain structure are separated from each other.
16. The semiconductor structure as claimed in claim 14 , wherein the gate structure and the extending portion of the source/drain structure are separated by the spacer.
17. The semiconductor structure as claimed in claim 14 , wherein the extending portion of the source/drain structure has a width in a range from about 10 Å to about 30 Å.
18. The semiconductor structure as claimed in claim 14 , wherein the spacer and the fin structure are not separated by a high dielectric material.
19. The semiconductor structure as claimed in claim 14 , wherein the spacer is made of silicon nitride, silicon carbide, silicon oxynitride, silcon carbon, silicon oxide, or a combination thereof.
20. The semiconductor structure as claimed in claim 14 , wherein the spacer is made of nitride.