Semiconductor device and method of fabricating the same

1. A semiconductor device, comprising:

at least one active pattern on a substrate;

at least one gate electrode intersecting the at least one active pattern;

source/drain regions on the at least one active pattern, the source/drain regions being on opposite sides of the at least one gate electrode;

a barrier layer between at least one of the source/drain regions and the at least one active pattern, the barrier layer being at least on a bottom of the at least one of the source/drain regions, and the barrier layer including oxygen; and

spacers on opposite sidewalls of the at least one gate electrode, at least one of the spacers overlapping and directly contacting both a topmost surface of the barrier layer and a topmost surface of the at least one of the source/drain regions.

2. The semiconductor device as claimed in claim 1 , wherein the barrier layer is between each one of the source/drain regions and the at least one active pattern, the barrier layer being conformal along each of the bottoms of the source/drain regions.

3. The semiconductor device as claimed in claim 2 , wherein:

the at least one active pattern includes recesses, the source/drain regions being in the recesses, and

the barrier layer is conformal along an entirety of each of the recesses.

4. The semiconductor device as claimed in claim 1 , wherein the barrier layer completely separates each source/drain region from the at least one active pattern.

5. The semiconductor device as claimed in claim 1 , wherein the barrier layer extends continuously along the bottom and corresponding sidewalls of each of the source/drain regions.

6. The semiconductor device as claimed in claim 1 , wherein the barrier layer is a silicon oxide layer separating each one of the source/drain regions from the at least one active pattern.

7. The semiconductor device as claimed in claim 6 , wherein the silicon oxide layer has a thickness of about 2 angstroms to about 5 angstroms.

8. The semiconductor device as claimed in claim 1 , further comprising at least one other barrier layer within the at least one of the source/drain regions, the at least one other barrier layer being spaced apart from the barrier layer.

9. The semiconductor device as claimed in claim 8 , wherein the at least one other barrier layer includes a same material as the barrier layer.

10. The semiconductor device as claimed in claim 9 , wherein each of the barrier layer and the at least one other barrier layer has a thickness of about 2 angstroms to about 5 angstroms.

11. The semiconductor device as claimed in claim 1 , wherein the at least one active pattern is a finFET pattern.

12. The semiconductor device as claimed in claim 1 , wherein the barrier layer is only between some of the source/drain regions and the at least one active pattern.

13. A semiconductor device, comprising:

at least one active finFET pattern on a substrate;

at least one gate electrode intersecting the at least one active finFET pattern;

source/drain regions on the at least one finFET pattern, the source/drain regions being on opposite sides of the at least one gate electrode;

a barrier layer between each one of the source/drain regions and the at least one finFET pattern, the barrier layer being conformal along bottoms of the source/drain regions, and the barrier layer including oxygen; and

spacers on opposite sidewalls of the at least one gate electrode, at least one of the spacers overlapping and directly contacting both a topmost surface of the barrier layer and a topmost surface of a corresponding one of the source/drain regions.

14. The semiconductor device as claimed in claim 13 , wherein the barrier layer is conformal along bottoms and corresponding sidewalls of each of the source/drain regions.

15. The semiconductor device as claimed in claim 13 , wherein the at least one active finFET pattern is a seed layer of the source/drain regions.

16. The semiconductor device as claimed in claim 13 , wherein a thickness of the barrier layer is smaller than a horizontal width of a bottom of the at least one of the spacers.

17. The semiconductor device as claimed in claim 13 , wherein the barrier layer is a silicon oxide layer having a thickness of about 2 angstroms to about 5 angstroms.

18. A semiconductor device, comprising:

at least one active pattern on a substrate;

at least one gate electrode intersecting the at least one active pattern;

source/drain regions on the at least one active pattern, the source/drain regions being on opposite sides of the at least one gate electrode;

a first barrier layer between each one of the source/drain regions and the at least one active pattern, the first barrier layer being at least on a bottom of the at least one of the source/drain regions, and the first barrier layer including oxygen;

spacers on opposite sidewalls of the at least one gate electrode, at least one of the spacers overlapping and directly contacting both a topmost surface of the first barrier layer and a topmost surface of the at least one of the source/drain regions; and

a second barrier layer between a topmost surface of each one of the source/drain region and a corresponding first barrier layer, the first and second barrier layers being spaced apart from each other,

wherein the first barrier layer is a silicon oxide layer separating each one of the source/drain regions from the at least one active pattern.

19. The semiconductor device as claimed in claim 18 , wherein the first barrier layer is continuous along an entire interface between each of the source/drain regions and the at least one active pattern.

20. The semiconductor device as claimed in claim 19 , wherein each of the first and second barrier layers is a silicon oxide layer formed by an epitaxial growth process.

21. The semiconductor device as claimed in claim 19 , wherein the second barrier layer has a same shape as the first barrier layer.