GeSn alloys and ordered phases with direct tunable bandgaps grown directly on silicon

• US 7,589,003 B2
• Filed: 06/14/2004
• Issued: 09/15/2009
• Est. Priority Date: 06/13/2003
• Status: Expired due to Fees

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Hu, Chang Wu, Bauer, Matthew, Kouvetakis, John, Tolle, John, Menendez, Jose, Tsong, Ignatius S. T.
• Primary Examiner(s): Ghyka; Alexander G
• Assistant Examiner(s): Patel; Reema
• Application Number:
  US10/559,981
• Publication Number:
  US 20070020891A1
• Time in Patent Office: 1,919 Days
• Field of Search: 438/479, 438/492, 438/503, 438/507
• US Class Current: 438/507
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/40 AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02535 including tin
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD

Abstract

A method for depositing an epitaxial Ge—Sn layer on a substrate in a CVD reaction chamber includes introducing into the chamber a gaseous precursor comprising SnD4 under conditions whereby the epitaxial Ge—Sn layer is formed on the substrate. the gaseous precursor comprises SnD4 and high purity H2 of about 15-20% by volume. The gaseous precursor is introduced at a temperature in a range of about 250° C. to about 350° C. Using the process device-quality Sn—Ge materials with tunable bandgaps can be grown directly on Si substrates.

Claims

1. A semiconductor structure comprising:

a substrate and a Sn_xGe_1-x layer formed directly on the substrate, wherein x has a value from about 0.02 to about 0.20, and wherein the substrate consists essentially of silicon.

2. The semiconductor structure of claim 1 wherein the Sn_xGe_1-x layer is an epitaxial layer with a direct band gap between about 0.72 eV and about 0.041 eV.

3. The semiconductor structure of claim 1, wherein x has a value of about 0.20 and the Sn_xGe_1-x layer is a direct-gap material.

4. The semiconductor structure of claim 1 wherein the substrate consists essentially of Si(100).

5. The semiconductor structure of claim 1 wherein the substrate consists essentially of Si(111).

6. The semiconductor structure of claim 1 wherein the Sn_xGe_1-x layer has a thickness of about 50nm to about 1000nm.

7. The semiconductor structure of claim 1 further comprising a strained Ge layer formed over the Sn_xGe_1-x layer.

8. The semiconductor structure of claim 7 wherein x is greater than about 0.11 and the strained Ge layer is a direct-gap material.

9. The semiconductor structure of claim 1, wherein the Sn_xGe_1-x layer is relaxed.

10. The semiconductor structure of claim 1, wherein the Sn_xGe_1-x layer is epitaxial.

11. The semiconductor structure of claim 10, wherein the substrate is accommodated by Lomer edge dislocations.

12. The semiconductor structure of claim 1, wherein the Sn_xGe_1-x layer lattice parameters are about 5.672 Å

to about 5.833 Å

.

13. The semiconductor structure of claim 1, wherein the Sn_xGe_1-x layer is atomically flat.

14. A method for depositing an epitaxial Ge—

Sn layer on a substrate in a chemical vapor deposition reaction chamber, the method comprising introducing into the chamber a gaseous precursor comprising SnD₄ under conditions whereby the epitaxial Ge—

Sn layer is formed on the substrate.

15. The method of claim 14 wherein the gaseous precursor comprises SnD₄ and high purity H₂.

16. The method of claim 14 wherein the gaseous precursor further comprises high purity H₂ of about 15-20 by volume.

17. The method of claim 14 wherein the gaseous precursor is introduced at a temperature in a range of about 250°

C. to about 350°

C.

18. The method of claim 14 wherein the substrate comprises silicon.

19. The method of claim 14 wherein the substrate comprises Si(100).

20. The method of claim 14 wherein the Ge—

Sn layer comprises Sn_xGe_1-x and x is in a range from about 0.02 to about 0.20.

21. The method of claim 14 wherein the gaseous precursor comprises SnD₄ and Ge₂H₆.

22. A method for depositing a strained Ge layer on a silicon substrate with a Ge—

Sn buffer layer in a chemical vapor deposition reaction chamber, the method comprising introducing into the chamber a combination comprising SnD₄ and Ge₂H₆ under conditions whereby the Ge—

Sn layer is formed on the substrate and dehydrogenating Ge₂H₆ under conditions whereby the Ge layer is formed on the Ge—

Sn buffer layer.