Fabrication and self-aligned local functionalization of nanocups and various plasmonic nanostructures on flexible substrates for implantable and sensing applications

Patent metadata

Field	Value
Publication number	US-9512000-B2
Application number	US-201514952876-A
Country	US
Kind code	B2
Filing date	Nov 25, 2015
Priority date	Dec 9, 2014
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

Methods for fabricating flexible substrate nanostructured devices are disclosed. The nanostructures comprise nano-pillars and metallic bulbs or nano-apertures. The nanostructures can be functionalized to detect biological entities. The flexible substrates can be rolled into cylindrical tubes for detection of fluidic samples.

First claim

What is claimed is:

1. A method comprising:
etching a silicon substrate to form silicon nanostructures on top of the silicon substrate;
oxidizing the silicon nanostructures to form silicon oxide nanostructures;
depositing a metallic layer on the silicon oxide nanostructures;
reflowing the metallic layer to form metallic bulbs on a top section of the silicon oxide nanostructures;
depositing a continuous flexible substrate on the metallic bulbs and on the silicon oxide nanostructures; and
removing the silicon substrate and the silicon oxide nanostructures.

2. The method of claim 1 , wherein the nanostructures are pillars.

3. The method of claim 1 , wherein the metallic layer is Au.

4. The method of claim 1 , wherein the continuous flexible substrate is polydimethylsiloxane.

5. The method of claim 1 , further comprising depositing a sacrificial layer between the silicon oxide nanostructures and the continuous flexible substrate.

6. The method of claim 1 , wherein the continuous flexible substrate is transparent to optical waves.

7. The method of claim 1 , further comprising reshaping the metallic bulbs prior to depositing the continuous flexible substrate.

8. The method of claim 7 , wherein reshaping comprises applying a focused ion beam with a different intensity for at least two metallic bulbs.

9. The method of claim 7 , wherein reshaping comprises ion milling the metallic bulbs.

10. The method of claim 7 , wherein reshaping comprises shadow evaporating at an angle.

11. The method of claim 10 , wherein shadow evaporating at an angle comprises shadow evaporating at an angle in successive steps, each step being at a different angle.

12. The method of claim 1 , further comprising bending the continuous flexible substrate with the nanostructures being on a concave side of the continuous flexible substrate.

13. The method of claim 12 , wherein bending the continuous flexible substrate comprises bending the continuous flexible substrate in a cylinder shape.

14. The method of claim 13 , wherein bending the continuous flexible substrate is carried out in a spiral fashion.

15. The method of claim 13 , wherein the continuous flexible substrate rolled in the cylinder shape is configured to contain a fluid sample flow within.

16. The method of claim 15 , wherein the continuous flexible substrate rolled in the cylinder shape is further configured to act as a waveguide for optical waves.

17. A method comprising:
etching a silicon substrate to form silicon nanostructures on top of the silicon substrate;
oxidizing the silicon nanostructures to form silicon oxide nanostructures;
depositing a metallic layer on the silicon oxide nanostructures and on the silicon substrate between the silicon oxide nanostructures;
reflowing the metallic layer to form metallic bulbs on a top section of the silicon oxide nanostructures while leaving parts of the metallic layer on the silicon substrate between the silicon oxide nanostructures;
removing the silicon oxide nanostructures to form nano-apertures between the parts of the metallic layer on the silicon substrate;
depositing a continuous sacrificial layer on the nano-apertures;
attaching a carrier chip to the continuous sacrificial layer;
removing the silicon substrate by etching;
depositing a continuous flexible substrate on a surface of the nano-apertures opposite to a surface with the continuous sacrificial layer; and
removing the continuous sacrificial layer and the carrier chip.

18. The method of claim 17 , further comprising inserting an adhesive layer between the continuous flexible substrate and the surface of the nano-apertures opposite to a surface with the continuous sacrificial layer, and wherein the removing the silicon oxide nanostructures is by etching or mechanical removal.

19. The method of claim 17 , wherein the nanostructures are pillars.

20. The method of claim 17 , wherein the metallic layer is Au.

21. The method of claim 17 , wherein the continuous flexible substrate is polydimethylsiloxane.

22. The method of claim 17 , further comprising depositing a sacrificial layer between the silicon oxide nanostructures and the continuous flexible substrate.

23. The method of claim 17 , wherein the continuous flexible substrate is transparent to optical waves.

24. The method of claim 17 , wherein removing the silicon oxide nanostructures to form nano-apertures comprises controlling a depth at which the nano-apertures are formed.

25. A method comprising:
etching a silicon substrate to form silicon nanostructures on top of the silicon substrate;
oxidizing the silicon nanostructures to form silicon oxide nanostructures;
depositing a metallic layer on the silicon oxide nanostructures;
reflowing the metallic layer to form metallic bulbs on a top section of the silicon oxide nanostructures;
depositing a photosensitive layer on the metallic bulbs and on the silicon oxide nano structures;
selecting an intensity for optical excitation to be above an excitation threshold only for the photosensitive layer between the metallic bulbs;
optically exciting at the selected intensity;
removing the excited photosensitive layer, thereby leaving gaps in the photosensitive layer between the metallic bulbs; and
functionalizing the gaps between the metallic bulbs.

26. The method of claim 25 , further comprising an adhesive layer attached to the continuous flexible substrate on a surface opposite the nanostructures.

Assignees

• California Inst Of Technonolgy
• California Inst Of Techn

Inventors

• Chang Chieh-Feng
• Walavalkar Sameer
• Fraser Scott E
• Scherer Axel

Classifications

• H10P50/268

  of silicon-containing layers · CPC title

• H10P14/69215

  the material being a silicon oxide, e.g. SiO2 · CPC title

• H01L21/32137

  Electricity · mapped topic

• H01L41/332

  Electricity · mapped topic

• B81C1/00476 Primary

  removing a sacrificial layer (B81C1/00912 takes precedence) · CPC title