Method for slowing down dopant-enhanced diffusion in substrates and devices fabricated therefrom

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

implanting, on a substrate, a dopant to form a dopant extension region;

implanting at least one species, on a substrate to form a region surrounding at least a portion of said dopant extension region; and

annealing said substrate, said at least one species retarding a diffusion of said dopant during said annealing of said substrate,

wherein said substrate comprises a graded SiGe layer having a crystal lattice which is more relaxed in a direction extending away from a top surface of the substrate and a concentration of Ge that increases in a direction extending away from the top surface of the substrate.

2. The method of claim 1 , wherein a dosage of said at least one species exceeds a preamorphization threshold of said substrate.

3. The method of claim 1 , wherein a dosage of said at least one species comprises at least about 3 times the preamorphization threshold of said substrate.

4. The method of claim 1 , wherein a dosage of said at least one species comprises at least about 5 times the preamorphization threshold of said substrate.

5. The method of claim 1 , wherein a dosage of said at least one species comprises at least about 7 times the preamorphization threshold of said substrate.

6. The method of claim 1 , wherein said at least one species damages a junction formed by the dopant.

7. The method of claim 6 , wherein said junction comprises a depth of no more than about 30 nm.

8. The method of claim 6 , wherein said junction comprises a slope which is at least about 5 nm per decade of change in concentration of said dopant.

9. The method of claim 1 , wherein said substrate comprises a material selected from the group consisting of silicon, SiGe, strained Si and strained SiGe.

10. The method of claim 1 , wherein said at least one species comprises a material selected from the group consisting of Xe, Ge, Si, Ar, Kr, Ne, He and N.

11. The method of claim 1 , wherein said dopant comprises a material selected from the group consisting of As, P and Sb.

12. The method of claim 1 , wherein said dopant is implanted at a dine which is one of prior to said implanting said species, and after said implanting said species.

13. The method of claim 1 , further comprising:

forming a source region and a drain region in said substrate; and

forming a metal suicide contact over said source region and said drain region.

14. The method of claim 13 , wherein said source region and said drain region are formed at a time which is prior to said implanting of said dopant.

15. The method of claim 13 , wherein said source region and said drain region are formed at a time which is after said implanting of said dopant.

16. The method of claim 14 , wherein said dopant is implanted at a time which is one of prior to said implanting said species, and after said implanting said species.

17. The method of claim 15 , wherein said dopant is implanted at a time which is one of prior to said implanting said species, and after said implanting said species.

18. The method of claim 1 , wherein said species is implanted at least about 10 to about 20 nm deeper than said dopant.

19. The method of claim 1 , wherein said species has an implantation energy sufficient to create said region surrounding at least a portion of said dopant extension region in said substrate.

20. The method of claim 1 , wherein said species has a first implantation energy sufficient to create said region surrounding at least a portion of said dopant extension region in said substrate, and a second implantation energy sufficient to create a region surrounding at least a portion of a source/drain region in said substrate.

21. The method of claim 1 , wherein said species has an implantation energy sufficient to create a region surrounding at least a portion of said extension region and at least a portion of a source/drain region in said substrate.

22. The method of claim 1 , wherein said annealing said substrate is performed after said implanting said dopant and said implanting said species.

23. A method of forming a shallow and abrupt junction in a semiconductor substrate, comprising:

implanting a dopant on a substrate to form a dopant extension region;

implanting at least one species in a vicinity of said dopant in a dosage which far exceeds a preamorphization threshold of said substrate to form a region surrounding at least a portion of said dopant extension region; and

annealing said substrate, said at least one species retarding a diffusion of said dopant during said annealing of said substrate, such that a shallow and abrupt junction is formed,

wherein said substrate comprises a graded SiGe layer having a crystal lattice which is more relaxed in a direction extending away from a top surface of the substrate and a concentration of Ge that increases in a direction extending away from the top surface of the substrate.

24. A semiconductor device, comprising:

a semiconductor substrate;

a dopant formed in said substrate, to define a junction; and

a species formed in a vicinity of said junction and in a concentration which far exceeds a preamorphization threshold of said substrate to form a region surrounding at least a portion of said junction,

wherein said substrate comprises a graded SiGe layer having a crystal lattice which is more relaxed in a direction extending away from a top surface of the substrate and a concentration of Ge that increases in a direction extending away from the top surface of the substrate.

25. The device of claim 24 , further comprising:

a source region and a drain region formed adjacent said dopant and said species;

a channel formed between said source region and said drain region;

a gate formed over said channel; and

a contact formed over said source region and said drain region.

26. The device of claim 25 , wherein a region of said species surrounds at least a portion of said junction, and at least a portion of said source region and said drain region.

27. The device of claim 24 , wherein said junction comprises a depth of no more than about 30 nm, and a slope which is at least about 5 cm per decade of change in concentration of dopant.

28. The device of claim 24 , wherein said substrate comprises one of silicon, SiGe, and strained Si.

29. The device of claim 28 , wherein said SiGe comprises one of relaxed SiGe and strained SiGe.

30. The device of claim 29 , wherein said strained SiGe comprises SiGe under one of a compressive strain and a tensile strain.

31. The method of claim 1 , wherein said substrate comprises a material selected from the group consisting of SiGe, strained Si, strained SiGe and relaxed SiGe.

32. The method of claim 1 , wherein said at least one species comprises a material selected from the group consisting of Xe, Kr, Ne, He and N.

33. The device of claim 24 , wherein said at least one species comprises a material selected from the group consisting of Xe, Kr He and N.

34. The method of claim 1 , wherein said at least one species comprises a material that is different from said dopant.

35. The method of claim 1 , further comprising:

forming a stained silicon channel adjacent said dopant extension region.

36. The method according to claim 1 , wherein said region surrounding at least a portion of said dopant extension region is formed under said dopant extension region and comprises a lip portion which extends along at least one side of said dopant extension region.

37. The method according to claim 1 , further comprising:

forming a disposable spacer to mask a region where said dopant is implanted.

38. The method of claim 1 , wherein said at least one species comprises a material selected from the group consisting of Xe, Ar, and Kr.

39. The method of claim 1 , wherein said dopant comprises As.

40. The method of claim 1 , wherein said at least one species comprises a material selected from the group consisting of Xe, Ar, and Kr, and

wherein said dopant comprises As.

41. The method of claim 1 , wherein said at least one species comprises Xe, and

wherein said dopant comprises As.