Methods of forming doped and un-doped strained semiconductor and semiconductor films by gas-cluster ion irradiation

• US 20050181621A1
• Filed: 02/14/2005
• Published: 08/18/2005
• Est. Priority Date: 02/14/2004
• Status: Active Grant

• Current Assignee: TEL Manufacturing and Engineering of America, Inc. (Tokyo Electron Limited)
• Original Assignee: Epion Corporation (Tokyo Electron Limited)
• Inventors: Hautala, John J., Tabat, Martin D., Borland, John O., Skinner, Wesley J.
• Granted Patent: US 7,259,036 B2
• Time in Patent Office: Days
• US Class Current: 438/752
• CPC Class Codes: H01J 2237/0812 Ionized cluster beam [ICB] sources
• CPC Class Codes: H01L 21/265 producing ion implantation
• CPC Class Codes: H01L 21/26506 in group IV semiconductors
• CPC Class Codes: H01L 21/26513 of electrically active species
• CPC Class Codes: H01L 21/26566 of a cluster, e.g. using a gas cluster ion beam
• CPC Class Codes: H01L 21/2658 of a molecular ion, e.g. decaborane
• CPC Class Codes: H01L 29/7842 means for exerting mechanical stress on the crystal lattice of the channel region, e.g. using a flexible substrate variation of the composition of the channel H01L29/1054

Abstract

Methods and apparatus are described for irradiating one or more substrate surfaces with accelerated gas clusters including strain-inducing atoms for blanket and/or localized introduction of such atoms into semiconductor substrates, with additional, optional introduction of dopant atoms and/or C. Processes for forming semiconductor films infused into and/or deposited onto the surfaces of semiconductor and/or dielectric substrates are also described. Such films may be doped and/or strained as well.

Claims

1. A method for forming one or more strained regions in a semiconductor substrate, comprising the steps of:

maintaining a reduced-pressure environment around a substrate holder for holding a semiconductor substrate having a surface;

holding the semiconductor substrate securely within said reduced-pressure environment;

providing to said reduced-pressure environment a gas-cluster ion beam from a pressurized gas mixture including at least one strain-inducing atom species;

accelerating the gas-cluster ion beam; and

irradiating the accelerated gas-cluster ion beam onto one or more portions of the surface of the semiconductor substrate to form one or more strained semiconductor regions within the substrate.

2. The method of claim 1, wherein the providing step further comprises the steps of:

delivering the pressurized gas mixture to an expansion nozzle;

flowing the pressurized gas mixture through the expansion nozzle into the reduced-pressure environment to form a jet containing gas-clusters; and

ionizing at least a portion of the gas-clusters to form the gas-cluster ion beam.

3. The method of claim 1, wherein:

the gas mixture further includes a noble gas; and

the strain-inducing atom species comprises at least one species selected from the group consisting of a semiconductor atom species and C.

4. The method of claim 1, wherein the gas mixture includes at least one atom species selected from the group consisting of Si and Ge.

5. The method of claim 1, wherein the gas mixture includes at least one dopant atom species selected from the group consisting of P, B and As.

6. The method of claim 1, wherein the strained region formed has a concentration of strain-inducing atom species of from about 5 to 40 atomic percent.

7. The method of claim 1, wherein the gas mixture includes a gas containing a dopant atom species, the gas present in the gas mixture in an amount of from about 0.01 to 10 molecular percent.

8. The method of claim 3, wherein:

the noble gas comprises Ar or Xe; and

the gas mixture further includes one or more gases selected from the group consisting of GeH₄, GeF₄, SiH₄, SiF₄, BF₃, B₂H₆, PH₃, PF₅, AsH₃, and AsF₅.

9. The method of claim 1, further comprising the step of providing a mask on the surface of the semiconductor substrate for controlling the portion of the surface of the semiconductor substrate that is irradiated.

10. The method of claim 9, wherein at least one of the one or more strained semiconductor regions induces strain in one or more adjacent un-irradiated regions of the semiconductor substrate.

11. The method of claim 1, wherein at least one of the one or more strained semiconductor regions is a doped strained semiconductor region.

12. The method of claim 1, wherein the semiconductor substrate is a crystalline, polycrystalline, or amorphous semiconductor.

13. The method of claim 1, wherein the semiconductor substrate is essentially silicon.

14. The method of claim 1, further comprising the step of annealing the one or more strained semiconductor regions.

15. The method of claim 2, further comprising the steps of controllably flowing the pressurized gas mixture so as to control nucleation of the gas mixture constituents into gas-clusters.

16. The method of claim 1, wherein the gas-clusters of the gas-cluster ion beam are accelerated by an acceleration voltage between 1 and 70 kV.

36. A method of forming one or more strained semiconductor regions in a semiconductor thin film at a surface of a substrate, comprising the steps of:

forming the semiconductor thin film at the surface of the substrate by the method of claim 17;

and

forming the one or more strained semiconductor regions in the semiconductor thin film by the method of claim 1.

38. A semiconductor substrate including one or more strained regions formed by irradiating one or more portions of the substrate with an accelerated gas-cluster ion beam as in the method of claim 1.

39. The substrate of claim 38, wherein the one or more strained regions include therein at least one atom species selected from the group consisting of semiconductor atom species, dopant atom species, and C.

40. The substrate of claim 38, wherein in the semiconductor substrate is a crystalline, polycrystalline, or amorphous semiconductor.

41. The substrate of claim 38, wherein in the semiconductor substrate is essentially silicon.

17. A method for forming a semiconductor thin film at a surface of a substrate, comprising the steps of:

maintaining a reduced-pressure environment around a substrate holder for holding a substrate having a surface;

holding the substrate securely within said reduced-pressure environment;

providing to said reduced-pressure environment a gas-cluster ion beam from a pressurized gas mixture including at least one semiconductor atom species;

accelerating the gas-cluster ion beam; and

irradiating the accelerated gas-cluster ion beam onto at least a portion of the surface of the substrate to form a semiconductor thin film.

18. The method of claim 17, wherein the providing step further comprises the steps of:

delivering the pressurized gas mixture to an expansion nozzle;

flowing the pressurized gas mixture through the expansion nozzle into the reduced-pressure environment to form a jet containing gas-clusters; and

ionizing at least a portion of the gas-clusters to form the gas-cluster ion beam.

19. The method of claim 17, wherein the gas mixture further includes a noble gas.

20. The method of claim 17, wherein the at least one semiconductor atom species is selected from the group of elements consisting of Si and Ge.

21. The method of claim 17, wherein the thin film formed has a concentration of at least one semiconductor atom species from about 5 to 40 atomic percent.

22. The method of claim 17, wherein the gas mixture further includes at least one dopant atom species selected from the group consisting of P, B and As.

23. The method of claim 17, wherein the gas mixture includes a gas containing at least one dopant atom species, the gas present in the gas mixture in an amount from about 0.01 to 10 molecular percent.

24. The method of claim 17, wherein the gas mixture further includes C.

25. The method of claim 24, wherein the concentration of C in the thin film formed is from about 5 to 40 atomic percent.

26. The method of claim 17, wherein:

the noble gas comprises Ar or Xe; and

the gas mixture further includes one or more gases selected from the group consisting of GeH₄, GeF₄, SiH₄, SiF₄, BF₃, B₂H₆, PH₃, PF₅, AsH₃, and AsF₅.

27. The method of claim 17, further comprising the step of providing a mask on a surface of the substrate for controlling the portion of the surface of the substrate that is irradiated by the accelerated gas-cluster ion beam.

28. The method of claim 17, wherein the semiconductor thin film is a doped semiconductor thin film.

29. The method of claim 17, wherein the substrate is composed of a semiconductor, a dielectric material, or a silicon-on-insulator material.

30. The method of claim 17, wherein the substrate is crystalline, polycrystalline, or amorphous.

31. The method of claim 17, wherein the semiconductor thin film comprises silicon carbide.

32. The method of claim 17, wherein:

the substrate is composed of a first semiconductor material;

the semiconductor thin film is composed of a second semiconductor material; and

the interface between the first semiconductor material and the second semiconductor material is of graded composition.

33. The method of claim 32, wherein:

the first semiconductor material is silicon;

the second semiconductor material is germanium; and

the interface between the silicon and the germanium is graded silicon/germanium.

34. The method of claim 17, further comprising the step of annealing the semiconductor thin film.

35. The method of claim 18, further comprising the steps of controllably flowing the pressurized gas mixture so as to control nucleation of the gas mixture constituents into gas-clusters.

37. The method of claim 17, wherein the gas-clusters of the gas-cluster ion beam are accelerated by an acceleration voltage between 1 and 70 kV.

42. A substrate including a thin semiconductor film at a surface of the substrate formed by irradiating the surface of the substrate with an accelerated gas-cluster ion beam as in the method of claim 17.

43. The substrate of claim 42, wherein the thin semiconductor film includes at least one atom species selected from the group consisting of semiconductor atom species, dopant atom species, and C.

44. The substrate of claim 42, wherein the substrate is composed of a semiconductor, a dielectric material, or a silicon-on-insulator material.

45. The substrate of claim 42, wherein the substrate is crystalline, polycrystalline, or amorphous.

46. The substrate of claim 42, wherein the semiconductor thin film comprises silicon carbide.

47. The substrate of claim 42, wherein:

the substrate is composed of a first semiconductor material;

the semiconductor thin film is composed of a second semiconductor material; and

the interface between the first semiconductor material and the second semiconductor material is of graded composition.

48. The substrate of claim 42, wherein:

the first semiconductor material is silicon;

the second semiconductor material is germanium; and

the interface between the silicon and the germanium is graded silicon/germanium.