Semiconductor component and fabricating method thereof

1. A method of fabricating a semiconductor component, the method comprising:

forming a first epitaxial layer cladding a first fin;

forming a second epitaxial layer cladding a second fin;

removing portions of the first epitaxial layer, the first fin, the second epitaxial layer, and the second fin;

forming a germanium-containing oxide layer on the second fin and on the second epitaxial layer; and

forming an epitaxial contact portion on the first fin and the first epitaxial layer.

2. The method of claim 1 , wherein the second epitaxial layer comprises SiGe, and the germanium-containing oxide layer is formed by oxidizing the second epitaxial layer.

3. The method of claim 1 , wherein a process temperature of forming the epitaxial contact portion is lower than a process temperature of forming the first epitaxial layer.

4. The method of claim 1 , wherein a doping concentration of the epitaxial contact portion is higher than a doping concentration of the first epitaxial layer.

5. The method of claim 1 , further comprising:

removing the germanium-containing oxide layer; and

forming silicide on the epitaxial contact portion and on the second epitaxial layer.

6. The method of claim 5 , further comprising:

pre-cleaning the first epitaxial layer and the first fin prior to forming the epitaxial contact portion, wherein the germanium-containing oxide layer remains on the second fin and on the second epitaxial layer after pre-cleaning the first epitaxial layer and the first fin.

7. The method of claim 5 , wherein the germanium-containing oxide layer is removed by a dry etching process.

8. The method of claim 1 , further comprising:

forming a plurality of metal contact portions respectively on the epitaxial contact portion and the second epitaxial layer.

9. A method, comprising:

forming a p-type epitaxial layer over a first semiconductor fin and an n-type epitaxial layer over a second semiconductor fin;

forming an interlayer dielectric (ILD) layer over the p-type epitaxial layer and the n-type epitaxial layer;

forming a first contact hole and a second contact hole in the ILD layer, wherein the first contact hole exposes a portion of the p-type epitaxial layer, the second contact hole exposes a portion of the n-type epitaxial layer;

oxidizing the exposed portion of the p-type epitaxial layer into a first oxide layer, and the exposed portion of the n-type epitaxial layer into a second oxide layer;

removing the second oxide layer from the n-type epitaxial layer by performing a first etching process that etches the second oxide layer at a faster etch rate than etching the first oxide layer;

after performing the first etching process, epitaxially growing an epitaxial contact over the n-type epitaxial layer; and

after epitaxially growing the epitaxial contact, forming a first metal contact in the first contact hole and a second metal contact in the second contact hole.

10. The method of claim 9 , further comprising:

removing the first oxide layer from the p-type epitaxial layer after epitaxially growing the epitaxial contact over the n-type epitaxial layer.

11. The method of claim 10 , wherein removing the first oxide layer is performed prior to forming the first and second metal contacts.

12. The method of claim 10 , wherein the first oxide layer is removed by a second etching process that uses a chemical different from a chemical used in the first etching process.

13. The method of claim 12 , wherein the epitaxial contact remains on the n-type epitaxial layer after the second etching process is complete.

14. The method of claim 9 , wherein the first oxide layer has a higher germanium concentration than that of the second oxide layer.

15. A method, comprising:

forming a dummy gate structure extending across a first semiconductor fin and a second semiconductor fin;

forming a p-type epitaxial layer over the first semiconductor fin and an n-type epitaxial layer over the second semiconductor fin;

replacing the dummy gate structure with a metal gate structure;

after replacing the dummy gate structure with the metal gate structure, performing an oxidation process to convert a surface layer of the p-type epitaxial layer into a first oxide layer, and a surface layer of the n-type epitaxial layer into a second oxide layer;

selectively etching the second oxide layer at least until the n-type epitaxial layer is exposed, wherein the first oxide layer remains on the p-type epitaxial layer after the selectively etching is complete;

after the selectively etching is complete, epitaxially growing an epitaxial contact over the n-type epitaxial layer; and

after epitaxially growing an epitaxial contact, forming a first metal contact over the n-type epitaxial layer and a second metal contact over the p-type epitaxial layer.

16. The method of claim 15 , wherein the p-type epitaxial layer is covered by the first oxide layer during epitaxially growing the epitaxial contact.

17. The method of claim 15 , further comprising:

after replacing the dummy gate structure with the metal gate structure, forming a spacer layer over the p-type and n-type epitaxial layers; and

etching spacer layer prior to oxidizing the p-type and n-type epitaxial layers.

18. The method of claim 17 , wherein etching the spacer layer is performed such that the n-type and p-type epitaxial layers are etched to form asymmetric patterns.

19. The method of claim 17 , wherein the etching the spacer layer is performed such a top end of the first semiconductor fin and a top end of the second semiconductor fin are exposed, and the oxidation process is performed such that the exposed top end of the first semiconductor fin is converted into a germanium-containing oxide, and the exposed top end of the second semiconductor fin is converted into a germanium-free oxide.

20. The method of claim 15 , further comprising:

after epitaxially growing the epitaxial contact, removing the first oxide layer from the p-type epitaxial layer; and

after removing the first oxide layer, forming a silicide layer over the p-type epitaxial layer.