High concentration indium fluorine retrograde wells

• US 20040188767A1
• Filed: 03/31/2003
• Published: 09/30/2004
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Cea, Stephen M., Curello, Giuseppe, Weber, Cory E., Wei, Max, Lilak, Aaron D., Hu, Sing-Chung, Armstrong, Mark A.
• Granted Patent: US 6,838,329 B2
• Time in Patent Office: Days
• US Class Current: 257/369
• CPC Class Codes: H01L 21/26506 in group IV semiconductors
• CPC Class Codes: H01L 21/26513 of electrically active species
• CPC Class Codes: H01L 21/2652 Through-implantation
• CPC Class Codes: H01L 21/26586 characterised by the angle between the ion beam and the crystal planes or the main crystal surface
• CPC Class Codes: H01L 21/823807 with a particular manufacturing method of the channel structures, e.g. channel implants, halo or pocket implants, or channel materials
• CPC Class Codes: H01L 21/823892 with a particular manufacturing method of the wells or tubs, e.g. twin tubs, high energy well implants, buried implanted layers for lateral isolation [BILLI]
• CPC Class Codes: H01L 29/167 further characterised by the doping material H01L29/1604 takes precedence
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• CPC Class Codes: H01L 29/665 using self aligned silicidation, i.e. salicide formation of conductive layers comprising silicides H01L21/28518
• CPC Class Codes: H01L 29/6656 using multiple spacer layers, e.g. multiple sidewall spacers

Abstract

A method and apparatus to form a high-concentration, indium-fluorine retrograde well within a substrate. The indium-fluorine retrograde well includes an indium concentration greater than about 3E18/cm3.

Claims

1. A method, comprising:

forming a high-concentration, indium-fluorine retrograde well within a substrate, the indium-fluorine retrograde well having an indium concentration greater than about 3E18/cm3.

2. The method of claim 1, wherein forming the indium-fluorine retrograde well comprises:

mixing indium atoms and fluorine atoms together inside a portion of the substrate; and

annealing the substrate with the indium atoms and the fluorine atoms to activate the indium, the fluorine preventing the indium from substantially diffusing during annealing.

3. The method of claim 1, wherein forming the indium-fluorine retrograde well comprises:

implanting indium ions into an area of the substrate at a dosage above about 2E13/cm2 at an energy above about 30 keV;

implanting fluorine ions into the same area of the substrate at a dosage above about 2E14/cm2 at an energy between about 5 keV-25 keV; and

annealing the substrate at a temperature above 700°

C.

26. The method of claim 1, wherein the indium-fluorine retrograde well comprises a shallow indium-fluorine retrograde well.

27. The method of claim 1, wherein the substrate comprises a monocrystalline silicon lightly doped with a p-type dopant.

28. The method of claim 1, further comprising:

forming a gate structure.

29. The method of claim 28, wherein the gate structure has a gate length less than about 60 nm.

30. The method of claim 1, wherein the indium-fluorine retrograde well comprises an indium-fluorine retrograde well having an indium concentration peak of about 1E19/cm3 at a depth of about 200 Å

.

4. A method, comprising:

implanting fluorine ions at a dosage above about 2E14/cm2 at an energy between about 5 keV-25 keV into a substrate surface to form a region of fluorine atoms;

implanting indium ions at a dosage above about 2E13/cm2 at an energy above about 30 keV into the region of fluorine atoms to form an indium-fluorine ion mixture inside the substrate; and

annealing the indium-fluorine ion mixture to activate the indium ions forming an activated indium-fluorine retrograde well having an indium concentration greater than about 3E18/cm3, the fluorine preventing the indium from substantially diffusing during the annealing.

5. The method of claim 4, including annealing the indium-fluorine ion mixture at a temperature above about 700°

C.

6. The method of claim 4, including implanting the indium ions into the substrate a dose of about 4E13/cm2 at an energy of about 50 keV and implanting the fluorine ions into the substrate surface at a dose of about 2E15/cm2 at an energy between about 10 keV to about 12 keV, to form an indium profile with a concentration peak at about 1E19/cm3.

7. The method of claim 4, including implanting the indium ions and the fluorine ions at an approximately vertical angle to the substrate surface.

8. The method of claim 4, wherein at least one gate structure is formed on the substrate surface and further including implanting the indium ions and the fluorine ions at an angle other than 90°

underneath the gate structure to form the indium-fluorine retrograde well beneath the gate structure.

31. The method of claim 8, wherein the gate structure comprises a gate structure having a gate length of less than about 60 nm.

9. A method, comprising:

forming at least one gate structure on a substrate surface;

implanting fluorine ions and indium ions into the substrate surface using an angled implant to form an indium-fluorine ion mixture inside the substrate underneath the gate structure; and

annealing the indium-fluorine ion mixture to activate the indium ions forming an activated indium-fluorine retrograde well, the fluorine preventing the indium from substantially diffusing during the annealing allowing an indium concentration greater than about 3E18/cm3.

10. The method of claim 9, including implanting the fluorine ions at a dosage above about 2E13/cm2 at an energy above about 30 keV and implanting the fluorine ions at a dosage above about 2E14/cm2 at an energy above between about 5 keV.

11. The method of claim 9, including implanting the fluorine ions and the indium ions at an angle of about 20°

to about 40°

from the substrate surface.

32. The method of claim 9, wherein annealing the indium-fluorine ion mixture comprises annealing the indium-fluorine ion mixture at a temperature above about 700°

C.

12. An apparatus, comprising:

an indium-fluorine retrograde well inside a substrate, the indium-fluorine retrograde well including an indium concentration greater than about 3E18/cm3.

13. The apparatus of claim 12, wherein the indium-fluorine retrograde well includes an indium concentration three times, or more, greater than 3E18/cm3.

14. The apparatus of claim 12, wherein the indium-fluorine retrograde well includes a fluorine concentration between about 5E18/cm3 to about 3E20/cm3.

15. The apparatus of claim 12, wherein the indium-fluorine retrograde well includes an indium concentration peak at about 200 Å

, or deeper, below the substrate surface.

16. An integrated circuit, comprising:

a substrate;

a gate structure formed on the substrate; and

an indium-fluorine retrograde well formed to a shallow depth below a surface of the substrate and beneath the gate structure.

17. The integrated circuit of claim 16, comprising an indium concentration above about 3E18.

18. The apparatus of claim 16, wherein the indium-fluorine retrograde well includes an indium concentration three times, or more, greater than 3E18/cm3.

19. The apparatus of claim 16, wherein the indium-fluorine retrograde well includes a fluorine concentration between about 5E18/cm3 to about 3E20/cm3.

20. The integrated circuit of claim 16, wherein the indium has a concentration peak at about 200 Å

, or deeper, below the substrate surface.

21. An apparatus, comprising:

a gate structure overlying a silicon substrate;

source/drain regions inside the silicon substrate, the source/drain regions adjacent to opposing sides of the gate structure and extending slightly underneath the gate structure; and

a fluorine-indium retrograde well directly beneath the gate structure and between the source/drain regions, the fluorine-indium retrograde well including an indium concentration greater than 3E18/cm3.

22. The apparatus of claim 21, wherein the fluorine-indium retrograde well is to provide a threshold voltage greater than about 360 mV.

23. The apparatus of claim 21, wherein the fluorine-indium retrograde well includes an indium concentration peak at about 200 Å

, or deeper, below the substrate surface.

24. The apparatus of claim 21, wherein the gate structure comprises a gate structure having a gate length of about 60 nm or less.

25. The apparatus of claim 21, wherein the fluorine-indium retrograde well includes an indium concentration three times, or more, greater than 3E18/cm3.