Semiconductor device and method for fabricating the same
A method for fabricating a semiconductor device includes the steps of first forming a gate structure on a substrate, forming a first spacer adjacent to the gate structure, forming a second spacer adjacent to the first spacer, forming an epitaxial layer adjacent to the second spacer, forming a second cap layer on the epitaxial layer, and then forming a first cap layer on the second cap layer. Preferably, a top surface of the first cap layer includes a V-shape and the first cap layer and the second cap layer are made of different materials.
1. A method for fabricating a semiconductor device, comprising:
forming a gate structure on a substrate;
forming an epitaxial layer adjacent to the gate structure; and
injecting a precursor and a reacting gas without any germanium-containing gas to directly form a first cap layer comprising a V-shape on the epitaxial layer, wherein a top surface of the first cap layer comprises the V-shape and a bottom surface of the first cap layer comprises a planar surface higher than a top surface of the substrate.
2. The method of claim 1 , further comprising:
forming a spacer adjacent to the gate structure; and
forming the epitaxial layer adjacent to the spacer.
3. The method of claim 1 , wherein the epitaxial layer comprises a second cap layer and the first cap layer is on the second cap layer.
4. The method of claim 3 , wherein a top surface of the second cap layer is higher than a top surface of the substrate.
5. The method of claim 3 , wherein a bottom surface of the second cap layer is even with a top surface of substrate.
6. The method of claim 3 , wherein the first cap layer and the second cap layer comprise different materials.
7. The method of claim 3 , wherein the epitaxial layer and the first cap layer comprise different materials.
8. The method of claim 1 , wherein a bottom surface of the first cap layer is higher than a top surface of the substrate.
9. The method of claim 1 , wherein a top surface of the first cap layer is higher than half the height of the gate structure.
10. A semiconductor device, comprising:
a gate structure on a substrate;
an epitaxial layer adjacent to the gate structure; and
a first cap layer on the epitaxial layer, wherein a top surface of the first cap layer comprises a V-shape and two planar surfaces connected to two sides of the V-shape and a bottom surface of the first cap layer comprises a planar surface higher than a top surface of the substrate.
11. The semiconductor device of claim 10 , further comprising:
a spacer adjacent to the gate structure; and
the epitaxial layer adjacent to the spacer.
12. The semiconductor device of claim 10 , wherein the epitaxial layer comprises a second cap layer, and the first cap layer is on the second cap layer.
13. The semiconductor device of claim 12 , wherein a top surface of the second cap layer is higher than a top surface of the substrate.
14. The semiconductor device of claim 12 , wherein a bottom surface of the second cap layer is even with a top surface of substrate.
15. The semiconductor device of claim 12 , wherein the first cap layer and the second cap layer comprise different materials.
16. The semiconductor device of claim 10 , wherein the epitaxial layer and the first cap layer comprise different materials.
17. The semiconductor device of claim 10 , wherein a bottom surface of the first cap layer is higher than a top surface of the substrate.
18. The semiconductor device of claim 10 , wherein a top surface of the first cap layer is higher than half the height of the gate structure.
19. A semiconductor device, comprising:
a gate structure on a substrate;
an epitaxial layer adjacent to the gate structure; and
a first cap layer on the epitaxial layer, wherein a top surface of the first cap layer comprises a curve concave upward and a bottom surface of the first cap layer comprises a planar surface higher than a top surface of the substrate.