Semiconductor device including barrier layer between active region and semiconductor layer and method of forming the same

1. A semiconductor device, comprising:

an isolation region defining an active region;

a barrier layer on the active region;

a first upper semiconductor layer on the barrier layer; and

a gate structure covering an upper surface, a lower surface, and side surfaces of the first upper semiconductor layer in a first direction,

wherein the first direction is a direction parallel to an upper surface of the active region,

the barrier layer is disposed between the gate structure and the active region,

the barrier layer includes first regions and a second region different from the first regions,

the first regions are spaced apart in a direction perpendicular to the upper surface of the active region by the second region interposed between the first regions,

each of the first regions includes a barrier impurity element, and

the second region includes the barrier impurity element having a concentration less than a concentration of the barrier impurity element in the first regions.

2. The semiconductor device of claim 1 , wherein the active region and the barrier layer include a well impurity element, and

a concentration of the well impurity element in the active region is less than a concentration of the well impurity element in a boundary region between the active region and the barrier layer, or a concentration of the well impurity element in the barrier layer adjacent to the active region.

3. The semiconductor device of claim 1 , wherein the barrier impurity element includes at least one of oxygen (O) and carbon (C).

4. The semiconductor device of claim 1 , further comprising:

a lower semiconductor layer between the first upper semiconductor layer and the barrier layer,

wherein the lower semiconductor layer contacts the barrier layer, and

the lower semiconductor layer is disposed between the barrier layer and the gate structure.

5. The semiconductor device of claim 1 , further comprising:

at least one second upper semiconductor layers on the first upper semiconductor layer; and

a first source/drain region and a second source/drain region on the active region,

wherein the active region extends from a portion overlapping the gate structure in a second direction,

the first upper semiconductor layer, and the at least one second upper semiconductor layers are disposed between the first source/drain region and the second source/drain region, and

the second direction is a direction parallel to the upper surface of the active region.

6. The semiconductor device of claim 5 , further comprising:

a lower semiconductor layer between the first upper semiconductor layer and the barrier layer,

wherein the lower semiconductor layer contacts the barrier layer,

the lower semiconductor layer is disposed between the barrier layer and the gate structure, and

the lower semiconductor layer contacts the first and second source/drain regions.

7. The semiconductor device of claim 5 , wherein each of the first and second source/drain regions contacts the barrier layer.

8. A semiconductor device comprising:

an isolation region defining an active region;

a barrier layer on the active region;

a first upper semiconductor layer on the barrier layer;

a gate structure covering an upper surface, a lower surface, and side surfaces of the first upper semiconductor layer in a first direction;

at least one second upper semiconductor layers on the first upper semiconductor layer; and

a first source/drain region and a second source/drain region on the active region,

wherein the first direction is a direction parallel to an upper surface of the active region,

the barrier layer is disposed between the gate structure and the active region,

the active region extends from a portion overlapping the gate structure in a second direction,

the first upper semiconductor layer, and the at least one second upper semiconductor layers are disposed between the first source/drain region and the second source/drain region,

the second direction is a direction parallel to the upper surface of the active region, and

the barrier layer further includes a first portion between the first source/drain region and the active region, and a second portion between the second source/drain region and the active region.

9. The semiconductor device of claim 8 , wherein the barrier layer includes first regions and a second region different from the first regions, and

the first regions are spaced apart in a direction perpendicular to the upper surface of the active region by the second region interposed between the first regions.

10. The semiconductor device of claim 9 , wherein each of the first regions includes a barrier impurity element, and

the second region includes the barrier impurity element having a concentration less than a concentration of the barrier impurity element in the first regions.

11. The semiconductor device of claim 9 , wherein each of the first regions is formed of a doped epitaxial silicon material including a barrier impurity element, and

the second region is formed of an un-doped epitaxial silicon material.

12. The semiconductor device of claim 9 , wherein the active region and the barrier layer include a well impurity element, and

a concentration of the well impurity element in the active region is less than a concentration of the well impurity element in a boundary region between the active region and the barrier layer, or a concentration of the well impurity element in the barrier layer adjacent to the active region.

13. The semiconductor device of claim 8 , further comprising:

a lower semiconductor layer between the first upper semiconductor layer and the barrier layer,

wherein the lower semiconductor layer contacts the barrier layer, and

the lower semiconductor layer is disposed between the barrier layer and the gate structure.

14. The semiconductor device of claim 13 , further comprising a first source/drain region and a second source/drain region on the active region,

wherein the lower semiconductor layer further includes a first semiconductor portion between the gate structure and the barrier layer and second semiconductor portions between the barrier layer and the first and second source/drain regions.

15. The semiconductor device of claim 14 , wherein a thickness of the first semiconductor portion is greater than a thickness of each of the second semiconductor portions.

16. A semiconductor device, comprising:

a well region;

a barrier epitaxial material layer grown from an upper surface of the well region;

a lower epitaxial semiconductor layer grown from an upper surface of the barrier epitaxial material layer;

a first upper epitaxial semiconductor layer disposed on the lower epitaxial semiconductor layer and spaced apart from the lower epitaxial semiconductor layer; and

a gate structure disposed on the first upper epitaxial semiconductor layer while filling a space between the first upper epitaxial semiconductor layer and the lower epitaxial semiconductor layer,

wherein the barrier epitaxial material layer includes first epitaxial regions and a second epitaxial region different from the first epitaxial regions,

the first epitaxial regions are spaced apart from each other in a vertical direction, perpendicular to the upper surface of the well region, and

the second epitaxial region is interposed between the first epitaxial regions.

17. The semiconductor device of claim 16 , wherein the barrier epitaxial material layer includes a barrier impurity element,

each of the first epitaxial regions includes the barrier impurity element, and

a concentration of the barrier impurity element in the second epitaxial region is one of about zero, or less than a concentration of the barrier impurity element in each of the first epitaxial regions.

18. The semiconductor device of claim 17 , wherein the well region and the barrier epitaxial material layer include a well impurity element different from the barrier impurity element, and

a concentration of the well impurity element in the well region is less than a concentration of the well impurity element in a boundary region between the well region and the barrier epitaxial material layer, or less than a concentration of the well impurity element in the barrier epitaxial material layer adjacent to the well region.

19. The semiconductor device of claim 16 , wherein the barrier epitaxial material layer includes a barrier impurity element, and the barrier impurity element includes at least one of oxygen (O) and carbon (C).

20. The semiconductor device of claim 16 , further comprising:

at least one of second upper epitaxial semiconductor layers on the first upper epitaxial semiconductor layer; and

a first source/drain region and a second source/drain region on the well region,

wherein the first upper epitaxial semiconductor layer, and the at least one of second upper epitaxial semiconductor layers are disposed between the first source/drain region and the second source/drain region, and

the gate structure is disposed on an uppermost upper epitaxial semiconductor layer of the at least one of second upper epitaxial semiconductor layers while filling a space between upper epitaxial semiconductor layers including the first upper epitaxial semiconductor layer and the at least one of second upper epitaxial semiconductor layers.