Silicon-Germanium Hydrides and Methods for Making and Using Same

• US 20100012972A1
• Filed: 11/21/2006
• Published: 01/21/2010
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Ritter III, Cole J., Tsong, Ignatius S.T., Chizmeshya, Andrew, Hu, Changwu, Kouvetakis, John
• Granted Patent: US 8,216,537 B2
• Time in Patent Office: Days
• US Class Current: 257/183
• CPC Class Codes: C01B 6/06 Hydrides of aluminium, gallium, indium, thallium, germanium, tin, lead, arsenic, antimony, bismuth or polonium; Monoborane; Diborane; Addition complexes thereof
• CPC Class Codes: C23C 16/22 characterised by the deposition of inorganic material, other than metallic material
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/52 Alloys
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD

Abstract

The present invention provides novel silicon-germanium hydride compounds, methods for their synthesis, methods for their deposition, and semiconductor structures made using the novel compounds.

Claims

1. A compound comprising a silicon-germanium hydride of the formula (SiH_n1)_x(GeH_n2)_y,

wherein x is 2, 3 or 4;

wherein y is 1, 2, or 3;

wherein x+y is 3, 4, or 5;

wherein n1 is independently 0, 1, 2, or 3 for each Si atom in the compound, to satisfy valency; and

wherein n2 is independently 0, 1, 2, or 3 for each Ge atom in the compound, to satisfy valency;

with the proviso that n2 is not 0 when y is 1;

with the further proviso that when x is 3 and y is 1, then n2 is 2 or 3; and

with the further proviso that when x is 2 and y is 1, then n2 is 3.

2. The compound of claim 1, wherein

wherein x is 2 or 3;

with the proviso that if y is 1, then n2 is 0, 1, or 2, and with the further proviso that if x is 2 and y is 2, then at least one of the following is true;

(i) n1 for at least one Si atom is 0, 1, or 2;

(ii) n2 for each Ge atom in the compound is 2; and

(iii) n2 for at least one Ge atom in the compound is 0 or 1.

3. The compound of claim 1, wherein

wherein y is 2 or 3;

wherein x+y is 4 or 5;

with the proviso that if x is 2 and y is 2, then at least one of the following is true;

(i) n1 for at least one Si atom is 0, 1, or 2;

(ii) n2 for each Ge atom in the compound is 2; and

(iii) n2 for at least one Ge atom in the compound is 0 or 1.

4. The compound of claim 1 wherein x is 2.

5. The compound of claim 4 wherein y is 2.

6. The compound of claim 1 wherein x is 3 and y is 1.

7. The compound of claim 1 wherein the silicon germanium hydride is listed in Table 1

8. The compound of claim 1 wherein the silicon germanium hydride is selected from the group consisting of

(H₃Ge)₂(SiH₂)₂;

and

(GeH₃)₂SiH(SiH₃).

9. The compound of claim 1 wherein the silicon germanium hydride is substantially isolated (H₃Ge)₂(SiH₂)₂.

10. The compound of claim 1 wherein the silicon germanium hydride comprises (H₃Ge)₂(SiH₂)₂ and (GeH₃)₂SiH(SiH₃).

11. The compound of claim 9, further comprising (GeH₃)₂(SiH₂GeH₂).

12. A composition, comprising two or more compounds according to claim 1.

13. The composition of claim 12, wherein either x is 3, or x is 2 and y is 2, for each of the two or more compounds.

14. A semiconductor structure, comprising

a substrate;

and

an Si—

Ge layer formed by introducing near the surface of a substrate a gaseous precursor comprising the compound of claim 1.

15. The semiconductor substrate of claim 14 wherein the substrate comprises silicon.

16. The semiconductor substrate of claim 15 wherein the substrate comprises Si(100).

17. The semiconductor substrate of claim 14 wherein the gaseous precursor comprises one or more of the compounds listed in Table 1.

18. The semiconductor substrate of claim 14 wherein the SiGe layer comprises an SiGe film having a thickness of less than one micron.

19. The semiconductor substrate of claim 14 wherein the SiGe layer comprises an SiGe film having a thickness in a range from 50 nm to 500 nm.

20. The semiconductor substrate of claim 14 wherein the SiGe layer comprises an SiGe film having a density of threading defects of 10⁶/cm² or less.

21. The semiconductor substrate of claim 14 wherein the SiGe layer comprises an SiGe film having a substantially atomically planar surface morphology.

22. The semiconductor substrate of claim 14 wherein the gaseous precursor comprises (H₃Ge)₂(SiH₂)₂.

23. A method of synthesizing one or more of the silicon-germanium hydrides of claim 1, comprising combining a perfluoroalkyl-sulfonate-substituted disilane with a compound comprising a GeH₃ ligand under conditions whereby the silicon-germanium hydride is formed.

24. The method of claim 23 wherein the compound comprising a GeH₃ ligand is selected from the group consisting of alkali and alkaline earth germanides.

25. The method of claim 23 wherein the method comprises combining the compound comprising a GeH₃ ligand with a nonafluorobutane-sulfonic substituted disilane, and wherein the nonafluorobutane-sulfonic substituted disilane comprises (SO₃C₄F₉)₂(SiH₂)₂.

26. The method of claim 23 wherein the method comprises combining the compound comprising a GeH₃ ligand with a triflate substituted disilane, and wherein the triflate substituted disilane comprises (SO₃CF₃)₂(SiH₂)₂.

27. The method of claim 23, wherein the compound comprising a GeH₃ ligand is KGeH₃, and wherein the silicon germanium hydride is formed according to the equation

(SO₃C₄F₉)₂(SiH₂)₂+2KGeH₃→

(H₃Ge)₂(SiH₂)₂+2KSO₃C₄F₉.

28. The method of claim 27, wherein the method comprises

(a) adding (C₄F₉SO₃)₂(SiH₂)₂ to a slurry of KGeH₃ in solvent at between −

50°

C. and −

30°

C. to form a mixture;

(b) warming the mixture to between −

20°

C. and 0°

C.;

(c) stirring the mixture under nitrogen;

(d) heating the mixture to between 25°

C. and 45°

C.; and

(e) distilling the mixture to form the (H₃Ge)₂(SiH₂)₂.

29. The method of claim 26, wherein the compound comprising a GeH₃ ligand is KGeH₃, and wherein the silicon germanium hydride is formed according to the equation

(SO₃CF₃)₂(SiH₂)₂+2KGeH₃→

(H₃Ge)₂(SiH₂)₂+2KSO₃CF₃.

30. The method of claim 29, wherein the method comprises

(a) adding CF₃SO₃)₂(SiH₂)₂ to a slurry of KGeH₃ in solvent at between −

40°

C. and—

20°

C. to form a mixture;

(b) warming the mixture to between 0°

C. and 35°

C.;

(c) stirring the mixture under nitrogen; and

(d) distilling the mixture to form the (H₃Ge)₂(SiH₂)₂.

31. The method of claim 30 wherein the reaction is carried out at a temperature of −

10°

C. or less.

32. The method of claim 30 wherein the reaction is carried out at a temperature of 22°

C. or higher.

33. A method for depositing a Si—

Ge material on a substrate in a reaction chamber, comprising introducing into the chamber a gaseous precursor comprising the compound of claim 1, under conditions whereby a layer comprising a Si—

Ge material is formed on the substrate.

34. A method for depositing an epitaxial Si—

Ge layer on a substrate, comprising

introducing near a surface of the substrate a gaseous precursor comprising the compound of claim 1; and

dehydrogenating the precursor under conditions whereby epitaxial Si—

Ge is formed on the substrate.

35. The method of claim 33 wherein the step of introducing the gaseous precursor comprises introducing the gaseous precursor in substantially pure form.

36. The method of claim 33 wherein the step of introducing the gaseous precursor comprises introducing the gaseous precursor as a single gas source.

37. The method of claim 33 wherein the step of introducing the gaseous precursor comprises introducing the gaseous precursor intermixed with an inert carrier gas.

38. The method of claim 37 wherein the inert carrier gas comprises H₂.

39. The method of claim 37 wherein the inert carrier gas comprises N₂.

40. The method of claim 33 wherein the gaseous precursor is deposited by gas source molecular beam epitaxy.

41. The method of claim 33 wherein the gaseous precursor is deposited by chemical vapor deposition.

42. The method of claim 33 wherein the gaseous precursor is introduced at a temperature of between 300°

C. and 450°

C.

43. The method of claim 33 wherein the gaseous precursor is introduced at a partial pressure between 10⁻

8 Torr and 1000 Torr.

44. The method of claim 33 wherein the Si—

Ge material is formed on the substrate as a strain-relaxed or uniformly strained layer having a planar surface.

45. The method of claim 33 wherein the composition of the Si—

Ge material is substantially uniform.

46. The method of claim 33 wherein the entire Si and Ge framework of the gaseous precursor is incorporated into the Si—

Ge material or epitaxial Si—

Ge.

47. The method of claim 33 wherein the gaseous precursor comprises one or more compounds listed in Table 1.

48. The method of claim 33 wherein the gaseous precursor is deposited by plasma enhanced chemical vapor deposition.

49. The method of claim 33 wherein the gaseous precursor is deposited by laser assisted chemical vapor deposition.

50. The method of claim 33 wherein the gaseous precursor is deposited by atomic layer deposition.

51. The method of claim 33 wherein the gaseous precursor comprises (H₃Ge)₂(SiH₂)₂.

52. The method of claim 33, wherein the substrate comprises germanium, silicon on insulator, Ge:

Sn alloys, SiO2, sapphire, quartz, Si;

Ge alloys, Si;

C alloys, stainless steel, and polyimide films.

53. The method of claim 52, wherein the substrate comprises silicon.

59. A semiconductor structure, comprising a substrate and an Si—

Ge layer comprising a backbone of compounds according to claim 1.

60. A composition, comprising one or more compounds according to claim 1 in an inert gas.

61. The composition of claim 60, wherein the inert gas is selected from the group consisting of H2, He, N2, and argon.

54. A compound comprising (SO₃C₄F₉)₂(SiH₂)₂.

55. A method for synthesizing (SO₃C₄F₉)₂(SiH₂)₂ comprising combining R(SiH₂)₂ and HSO₃C₄F₉ under conditions whereby the (SO₃C₄F₉)₂(SiH₂)₂ is formed, where R is an aryl substituent such as p-tolyl or benzyl.

56. A method for synthesizing (SO₃C₄F₉)₂(SiH₂)₂ comprising combining (p-tolyl)₂(SiH₂)₂ and HSO₃C₄F₉ under conditions whereby the (SO₃C₄F₉)₂(SiH₂)₂ is formed.

57. The method of claim 56, wherein the (SO₃C₄F₉)₂(SiH₂)₂ is formed according to the equation

(p-tolyl)₂(SiH₂)₂+2HSO₃C₄F₉→

(SO₃C₄F₉)₂(SiH₂)₂+2(toluene)

58. The method of claim 56 wherein the method comprises

(a) combining HSO₃C₄F₉, (p-tolyl)₂(SiH₂)₂, and solvent in a reaction chamber at between −

50°

C. and 0°

C. to form a mixture;

(b) warming the mixture to between 20°

C. and 25°

C.;

(c) stirring the mixture; and

(d) filtering the solid (SO₃C₄F₉)₂(SiH₂)₂.