Method for alignment of microwires

Patent metadata

Field	Value
Publication number	US-9553223-B2
Application number	US-201414163745-A
Country	US
Kind code	B2
Filing date	Jan 24, 2014
Priority date	Jan 24, 2013
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A method of aligning microwires includes modifying the microwires so they are more responsive to a magnetic field. The method also includes using a magnetic field so as to magnetically align the microwires. The method can further include capturing the microwires in a solid support structure that retains the longitudinal alignment of the microwires when the magnetic field is not applied to the microwires.

First claim

The invention claimed is:

1. A method of forming a device, comprising:
modifying silicon microwires so as to increase the responsivity of the silicon microwires to a magnetic field;
using the magnetic field to longitudinally align the silicon microwires; and
at least partially embedding the aligned silicon microwires in a polymer to maintain longitudinal alignment of the silicon microwires.

2. The method of claim 1 , wherein using the magnetic field includes applying the magnetic field to the microwires such that more than 90% of the microwires each has a longitudinal axis that is within 7° of the direction of the magnetic field.

3. The method of claim 1 , wherein the longitudinal axis of less than 90% of the microwires was within 7° of the direction of the magnetic field before using the magnetic field.

4. The method of claim 1 , wherein modifying the microwires includes forming a coating of a material on a body of the microwire.

5. The method of claim 4 , further comprising:
removing at least a portion of the coating after using the magnetic field.

6. The method of claim 4 , wherein the coating is more than 20 nm thick.

7. The method of claim 4 , wherein coating includes a ferromagnetic material.

8. The method of claim 7 , wherein forming the coating includes electroplating or sputtering the microwires with the ferromagnetic material.

9. The method of claim 8 , wherein the ferromagnetic material includes at least one components selected from nickel and cobalt.

10. The method of claim 1 , further comprising:
placing the microwires in a liquid so as to form an alignment liquid before using the magnetic field.

11. The method of claim 10 , further comprising:
placing the alignment liquid on a substrate before using the magnetic field.

12. The method of claim 11 , further comprising:
making a surface of the substrate hydrophilic before placing the placing the alignment liquid on the surface of the substrate.

13. The method of claim 11 , wherein the electrical field is used such that ends of the aligned microwires are pulled into contact with the surface of the substrate.

14. The method of claim 11 , wherein the alignment liquid is placed on a surface of the substrate such that less than 90% of the microwires was within 7° of the direction of the magnetic field before using the magnetic field.

15. The method of claim 14 , wherein the magnetic field causes the microwires to re-arrange themselves in the alignment liquid such that more than 90% of the microwires have a longitudinal axis that is within 7° of the line that is perpendicular to the surface of the substrate.

16. The method of claim 1 , further comprising:
capturing the longitudinally aligned microwires in a solid support that holds the microwires in a longitudinally aligned configuration when the magnetic field is not applied to the microwires.

17. The method of claim 16 , wherein modifying the microwires includes forming a coating of a material on a body of the microwire, and further comprising:
removing at least a portion of the coating after capturing the longitudinally aligned microwires in the solid support.

18. The method of claim 1 , wherein the microwires have a diameter that is less than 2 μm and an aspect ratio that is greater than 10.

Assignees

• California Inst Of Techn

Inventors

• Beardslee Joseph A
• Lewis Nathan S
• Sadtler Bryce

Classifications

• H01F41/26

  using electric currents {, e.g. electroplating} · CPC title

• H01L31/0352 Primary

  Electricity · mapped topic

• Y10T29/4902

  Electromagnet, transformer or inductor · CPC title

• H10F77/14 Primary

  Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies · CPC title