Semiconductor devices and methods of fabricating the same

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

patterning a substrate to form active patterns;

forming a gate layer comprising openings on the substrate;

forming a gate separation layer filling the openings and extending on the gate layer;

forming a gate mask pattern that has a linear shape extending in a first direction and overlaps the gate layer and a portion of the gate separation layer in one of the openings; and

forming a pair of gate electrodes and a gate separation pattern by etching the portion of the gate separation layer and the gate layer using the gate mask pattern as an etch mask,

wherein the pair of gate electrodes are spaced apart from each other and are arranged in the first direction, and

wherein the gate separation pattern is disposed between the pair of gate electrodes.

2. The method of claim 1 , wherein each of the openings of the gate layer has a longitudinal axis that extends in a second direction that is different from the first direction.

3. The method of claim 2 , wherein lengths of the openings in the second direction are greater than widths of the pair of gate electrodes in the second direction.

4. The method of claim 1 , wherein each of the openings is formed between adjacent ones of the active patterns when viewed from a plan perspective.

5. The method of claim 1 , wherein the forming of the gate layer comprises:

forming a lower layer on the substrate;

forming a first mask pattern comprising first preliminary openings on the lower layer; and

etching the lower layer using the first mask pattern as an etch mask to form the openings.

6. The method of claim 1 , wherein forming the pair of gate electrodes and the gate separation pattern comprises concurrently etching the portion of the gate separation layer and the gate layer using the gate mask pattern as the etch mask.

7. The method of claim 1 , wherein the patterning of the substrate to form the active patterns comprises:

forming a mask pattern defining the active patterns on the substrate;

etching the substrate using the mask pattern as an etch mask to form trenches; and

forming a device isolation layer in the trenches, the device isolation layer exposing upper portions of sidewalls of the trenches.

8. The method of claim 1 , further comprising:

forming a pair of gate spacers extending in the first direction, wherein the pair of gate spacers define a recess therebetween, and the recess extends in the first direction, and

wherein the pair of gate electrodes and the gate separation pattern are in the recess.

9. The method of claim 8 , further comprising:

etching portions of the active patterns at both sides of each of the pair of gate electrodes to form active recesses after forming the pair of gate spacers; and

forming epitaxial layers in the respective active recesses.

10. A method of fabricating a semiconductor device comprising:

forming a device isolation layer on a substrate, the device isolation layer defining an active pattern;

forming a gate separation pattern overlapping the device isolation layer when viewed from a plan perspective, the gate separation pattern comprising an electrically insulating material, and the gate separation pattern comprising first opposing sidewalls extending in a first direction and second opposing sidewalls extending in a second direction that is different from the first direction;

forming first and second gate spacers on the respective first opposing sidewalls of the gate separation pattern, the first and second gate spacers crossing over the active pattern, extending in the first direction, and defining first and second gate recesses therebetween, and the second opposing sidewalls of the gate separation pattern defining sides of the first and second gate recesses, respectively; and

forming first and second gate electrodes in the first and second gate recesses, respectively, the first gate electrode crossing over the active pattern, the first and second gate electrodes extending in the first direction, and the first gate electrode, the gate separation pattern, and the second gate electrode being sequentially arranged along the first direction.

11. The method of claim 10 further comprising:

forming a dummy gate layer on the substrate after forming the device isolation layer, the dummy gate layer comprising an opening exposing the device isolation layer;

forming a gate separation layer in the opening of the dummy gate layer and on the dummy gate layer;

forming a mask pattern having a linear shape on the dummy gate layer and the gate separation layer;

forming the gate separation pattern and first and second dummy gate patterns by etching the gate separation layer and the dummy gate layer using the mask pattern as an etch mask, the first and second dummy gate patterns being on the respective second opposing sidewalls of the gate separation pattern; and

removing the first and second dummy gate patterns after forming the first and second gate spacers on the respective first opposing sidewalls of the gate separation pattern to form the first and second gate recesses between the first and second gate spacers.

12. The method of claim 11 , wherein the gate separation layer fills the opening of the dummy gate layer, and

wherein the first and second gate recesses expose the second opposing sidewalls of the gate separation pattern.

13. The method of claim 11 further comprising:

forming first and second active recesses in the active pattern on respective sides of the first dummy gate pattern by etching the active pattern using the gate separation pattern, the first and second dummy gate patterns and the first and second gate spacers as an etch mask;

forming epitaxial layers in the first and second active recesses; and

forming an interlayer insulating layer on the gate separation pattern, the first and second dummy gate patterns, the first and second gate spacers and the epitaxial layers.

14. The method of claim 13 , wherein the interlayer insulating layer exposes upper surfaces of the gate separation pattern and the first and second dummy gate patterns, and

wherein removing the first and second dummy gate patterns is performed after forming the interlayer insulating layer.

15. The method of claim 10 , wherein the first and second gate spacers contact the respective first opposing sidewalls of the gate separation pattern.

16. The method of claim 15 , wherein the first and second gate spacers comprise a material different from the gate separation pattern.

17. The method of claim 15 , wherein the first and second gate spacers are spaced apart from each other by a constant distance along the first direction.

18. The method of claim 10 , further comprising forming first and second gate insulating layers in the first and second gate recesses, respectively, before forming the first and second gate electrodes, wherein the first gate insulating layer is between the first gate electrode and the gate separation pattern and contacts a first one of the second opposing sidewalls of the gate separation pattern, and

wherein the second gate insulating layer is between the second gate electrode and the gate separation pattern and contacts a second one of the second opposing sidewalls of the gate separation pattern.

19. The method of claim 10 , wherein an upper surface of the gate separation pattern and an upper surface of the first gate electrode are coplanar.

20. The method of claim 19 , wherein a lower surface of the gate separation pattern is lower than a lower surface of the first gate electrode.