Methods of manufacturing semiconductor devices

1. A method of manufacturing a semiconductor device, comprising:

forming a gate structure on a substrate;

forming a sacrificial spacer on a sidewall of the gate structure;

implanting first impurities into portions of the substrate to form a source region and a drain region by a first ion implantation process using the gate structure and the sacrificial spacer as ion implantation masks;

removing the sacrificial spacer; and

subsequent to forming the source region and the drain region and removing the sacrificial spacer, implanting second impurities and carbon atoms into portions of the substrate to form a source extension region and a drain extension region and carbon doping regions, respectively, by at least second ion implantation process using the gate structure as an ion implantation mask.

2. The method of claim 1 , further comprising performing a heat treatment about the substrate to activate the first impurities in the source region and the drain region before performing the second ion implantation process.

3. The method of claim 1 , wherein the first and the second impurities include N type impurities, and the source region and the drain region have impurity concentrations higher than those of the source extension regions and the drain extension regions, respectively.

4. The method of claim 1 , wherein the source extension region and the drain extension region are adjacent to the source region and the drain region, respectively, and the source extension region and the drain extension region have depths less than depths of the source region and the drain region, respectively.

5. The method of claim 1 , wherein the source extension region and the drain extension region and the carbon doping regions are formed by different ion implantation processes, respectively.

6. The method of claim 1 , further comprising, after forming the source extension region and the drain extension region and the carbon doping regions, performing a thermal treatment process about the substrate to activate the second impurities in the source extension region and the drain extension region and carbon atoms in the carbon doping regions.

7. The method of claim 1 , wherein the carbon doping regions are adjacent to the source region and the drain region and the source extension region and the drain extension region, and the carbon doping regions have depths greater than depths of the source region and the drain region.

8. The method of claim 1 , further comprising forming an epitaxial layer on the source region and the drain region and the substrate after removing the sacrificial spacer.

9. The method of claim 1 , wherein forming the gate structure comprises:

forming a gate insulation layer pattern and a gate electrode on the substrate; and

forming a spacer on sidewalls of the gate insulation layer pattern and the gate electrode.

10. A method of manufacturing a semiconductor device, comprising:

forming a first gate structure and a second gate structure on an NMOS region and a PMOS region of a substrate, respectively;

forming a first sacrificial spacer and a second sacrificial spacer on sidewalls of the first gate structure and the second gate structure, respectively;

implanting first impurities into the NMOS region to form a first source region and a first drain region by a first ion implantation process using the first gate structure and the first sacrificial spacer as ion implantation masks;

implanting second impurities into the PMOS region to form a second source region and a second drain region by a second ion implantation process using the second gate structure and the second sacrificial spacer as ion implantation masks;

removing the first and the second sacrificial spacers;

implanting third impurities into the PMOS region to form a second source extension region and a second drain extension region by a third ion implantation process using the second gate structure as an ion implantation mask; and

subsequent to the implanting the second impurities, the removing the first and second sacrificial spacers, and the implanting the third impurities, implanting fourth impurities and carbon atoms into the NMOS region to form a first source extension region and a first drain extension region and carbon doping regions, respectively, by at least a fourth ion implantation process using the first gate structure as an ion implantation mask.

11. The method of claim 10 , wherein forming the second source region and the second drain region comprises:

partially removing the substrate using the second gate structure and the second sacrificial spacer as etching masks to form recesses in the PMOS region;

forming a first epitaxial layer to fill the recesses; and

implanting the second impurities into the first epitaxial layer.

12. The method of claim 10 , further comprising performing a heat treatment to activate the first and the second impurities in the first and the second source and drain regions before the fourth ion implantation process.

13. The method of claim 10 , wherein the first and the fourth impurities include N type impurities, and the second and the third impurities include P type impurities,

and wherein the first and the second source and drain regions have impurity concentrations larger than those of the first and the second source and drain extension regions.

14. The method of claim 10 , wherein the carbon doping regions are adjacent to the first source region and the first drain region and the first source extension region and the first drain extension region, and the carbon doping regions have depths greater than depths of the first source region and the first drain region.

15. The method of claim 10 , further comprising forming a second epitaxial layer on the first source region and the first drain region and the NMOS region after removing the sacrificial spacers.

16. A method of manufacturing a semiconductor device, comprising:

forming a gate structure on a substrate;

forming source and drain regions in the substrate;

performing a first heat treatment process on the substrate; and

forming a carbon doping region in the substrate beneath the source and drain regions, subsequent to forming the source and drain regions.

17. The method of claim 16 , wherein the first heat treatment is performed on the substrate at a temperature of about 800° C. to about 1,100° C. for about 0.01 second to about 10 seconds.

18. The method of claim 16 , wherein carbon atoms are doped in the carbon doping region with a dose concentration in a range of about 5×10 19 atoms/cm 2 to about 5×10 21 atoms/cm 2 .

19. The method of claim 16 , wherein the carbon doping region has a depth in a range of about 10 Å to about 1,000 Å from a surface of the substrate.

20. The method of claim 16 , further comprising performing a second heat treatment process at a temperature of about 1,000° C. to 1,300° C. for about several milliseconds to about hundreds of milliseconds on the substrate after forming the carbon doping region.