SELECTIVE PROCESSING OF SEMICONDUCTOR NANOWIRES BY POLARIZED VISIBLE RADIATION

• US 20080150165A1
• Filed: 11/07/2007
• Published: 06/26/2008
• Est. Priority Date: 11/29/2006
• Status: Active Grant

• Current Assignee: OneD Material LLC, Regents of the University of California (University of California)
• Original Assignee: Nanosys Incorporated (Shoei Electronic Materials, Inc.)
• Inventors: Pan, Yaoling, Stumbo, David P., Grigoropoulos, Costas P., Misra, Nipun
• Granted Patent: US 7,786,024 B2
• Time in Patent Office: Days
• US Class Current: 257/784
• CPC Class Codes: B23K 26/073 Shaping the laser spot
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H01L 21/26513 of electrically active species
• CPC Class Codes: H01L 21/2658 of a molecular ion, e.g. decaborane
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 29/0665 the shape of the body defining a nanostructure nanotechnology per se B82B
• CPC Class Codes: H01L 29/0673 oriented parallel to a substrate
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Methods, systems, and apparatuses for annealing semiconductor nanowires and for fabricating electrical devices are provided. Nanowires are deposited on a substrate. A plurality of electrodes is formed. The nanowires are in electrical contact with the plurality of electrodes. The nanowires are doped. A polarized laser beam is applied to the nanowires to anneal at least a portion of the nanowires. The nanowires may be aligned substantially parallel to an axis. The laser beam may be polarized in various ways to modify absorption of radiation of the applied laser beam by the nanowires. For example, the laser beam may be polarized in a direction substantially parallel to the axis or substantially perpendicular to the axis to enable different nanowire absorption profiles.

Claims

1. A method for fabricating an electrical device, comprising:

depositing at least one nanowire on a substrate;

forming first and second metal electrodes, the at least one nanowire being in electrical contact with the first and second metal electrodes;

doping the at least one nanowire; and

applying a polarized laser beam to the at least one nanowire to anneal the at least one nanowire.

2. The method of claim 1, wherein said depositing comprises:

aligning the at least one nanowire to be substantially parallel to an axis.

3. The method of claim 1, wherein said applying comprises:

polarizing the laser beam in a direction substantially parallel to the axis.

4. The method of claim 3, wherein said applying further comprises:

irradiating the at least nanowire with the polarized laser beam at a fluence level less than 28 mJ/cm².

5. The method of claim 1, wherein said applying comprises:

polarizing the laser beam in a direction substantially perpendicular to the axis.

6. The method of claim 5, wherein said applying further comprises:

irradiating the at least nanowire with the polarized laser beam at a fluence level less than 100 mJ/cm².

7. The method of claim 1, further comprising:

selecting a fluence level of the polarized laser beam to anneal the at least one nanowire without melting the at least one nanowire.

8. The method of claim 1, wherein said applying comprises:

pulsing the polarized laser beam.

9. The method of claim 1, further comprising:

forming a third electrode in electrical contact with the at least one nanowire.

10. The method of claim 1, wherein said applying comprises:

forming the polarized laser beam to have a substantially flat top beam profile.

11. The method of claim 1, wherein said applying comprises:

generating the polarized laser beam to have a visible light frequency.

12. The method of claim 1, wherein said applying comprises:

ablating at least one nanowire.

13. An electrical device fabricated according to the method of claim 1.

14. A system for fabricating an electrical device, comprising:

a laser configured to generate a polarized laser beam;

optics configured to direct the polarized laser beam onto an electrical device region of a substrate;

wherein an electrical device in the electrical device region includes at least one doped nanowire in electrical contact with first and second metal electrodes; and

wherein the electrical device receives the directed polarized laser beam, and the received directed polarized laser beam is configured to anneal the at least one nanowire.

15. The system of claim 14, wherein the at least one nanowire is aligned to be substantially parallel to an axis.

16. The system of claim 15, wherein the substrate is positioned such that the directed polarized laser beam is received by the electrical device having an incident polarization substantially parallel to the axis.

17. The system of claim 15, wherein the substrate is positioned such that the directed polarized laser beam is received by the electrical device having an incident polarization substantially perpendicular to the axis.

18. The system of claim 14, wherein the polarized laser beam has a fluence level configured to anneal the at least one nanowire without melting the at least one nanowire.

19. The system of claim 14, wherein the laser is configured to pulse the polarized laser beam.

20. The system of claim 14, wherein the laser is configured to generate the polarized laser beam to have a visible light frequency.

21. The system of claim 14, further comprising:

a third electrode in electrical contact with the at least one nanowire.

22. The system of claim 14, wherein the optics is configured to form the polarized laser beam to have a substantially flat top beam profile.

23. The system of claim 14, wherein the substrate is a flexible plastic substrate.

24. The system of claim 14, wherein the polarized laser beam is configured to anneal nanowires substantially aligned with an axis and to ablate nanowires aligned substantially perpendicularly to the axis.

25. A method for annealing at least nanowire, comprising:

irradiating at least a portion of the at least one nanowire with a polarized laser beam having a visible light frequency.