Method of forming a nano-structure

Patent metadata

Field	Value
Publication number	US-9359195-B2
Application number	US-201013822075-A
Country	US
Kind code	B2
Filing date	Oct 21, 2010
Priority date	Oct 21, 2010
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Nano-structure includes a substrate and a non-oxidized portion of a metal layer (having an expansion coefficient, during oxidation, that is more than 1) on the substrate. An oxide layer is formed on the non-oxidized portion. A plurality of metal oxide nano-pillars is grown from the oxide layer. Each nano-pillar is grown through a plurality of pores defined in a template. A space is defined between adjacent nano-pillars. A continuous metal oxide cap layer is over the nano-pillars and over, but not in, the space between adjacent nano-pillars. The cap layer is formed from end portions of the nano-pillars that merge together over a template surface. The cap layer is in contact with all of the nano-pillars. The oxide layer, the nano-pillars, and the oxide cap layer are formed from anodization of portions of the metal layer.

First claim

What is claimed is:

1. A method of forming a nano-structure, comprising:
forming a multi-layered structure including i) a first oxidizable material layer established on a substrate, and ii) a second oxidizable material layer established on the first oxidizable material layer, the first oxidizable material layer being formed of a metal layer having an expansion coefficient, during oxidation, that is more than 1;
forming a template out of the second oxidizable material layer, the template including a plurality of pores defined therein;
growing an oxide structure from the first oxidizable material layer through each of the plurality of pores and over a surface of the template, wherein the growing of the oxide structure includes anodizing portions of the metal layer to form an oxide layer on a non-oxidized portion of the metal layer and to grow an individual metal oxide nano-pillar from the oxide layer inside each of the plurality of pores that are oriented in a position that is substantially normal to the substrate, and wherein the growing of the oxide structure over the surface of the template includes merging respective end portions of the individual metal oxide nano-pillars to form a continuous metal oxide cap layer; and
selectively removing the template to expose the plurality of metal oxide nano-pillars and to form a space defined between adjacent metal oxide nano-pillars;
wherein the continuous metal cap layer is in contact with all of the metal oxide nano-pillars, and is over the plurality of metal oxide nano-pillars and over, but not in, the space between the adjacent metal oxide nano-pillars;
and wherein each of the metal oxide nano-pillars has a diameter ranging from about 10 nm to about 350 nm and a height ranging from about 10 nm to 1000 nm.

2. The method as defined in claim 1 wherein the forming of the template and the growing of the oxide structure are accomplished via anodization using any of oxalic acid, sulfuric acid, phosphoric acid, chromic acid or mixtures thereof as an electrolyte.

3. The method as defined in claim 1 wherein the first oxidizable material is chosen from tantalum, niobium, tungsten, titanium, alloys thereof, and mixtures thereof.

4. The method as defined in claim 1 wherein the forming of the template is accomplished by anodizing the second oxidizable material layer.

5. The method as defined in claim 1 wherein prior to selectively removing the template, the method further comprises patterning the cap layer and the template to form a pre-nano-island, the patterning including selectively removing a portion of the cap layer, a portion of the template, and some of the plurality of individual nano-pillars.

6. The method as defined in claim 1 , further comprising tuning at least one of the height, a pitch, the diameter, a gap, or an aspect ratio of the individual nano-pillars by adjusting at least one parameter of an anodizing process utilized to grow the oxide structure, to form the template, or combinations thereof.

7. The method as defined in claim 1 , further comprising modifying a surface chemistry of the individual nano-pillars, the cap layer, or combinations thereof, the modifying being accomplished by depositing an other material on a surface of each of the nano-pillars, the cap layer, or combinations thereof.

8. The method as defined in claim 1 , further comprising controlling a mass of the nano-structure by adjusting at least one of a thickness of the cap layer or a lateral area of the cap layer.

9. A nano-structure, comprising:
a substrate;
a non-oxidized portion of a metal layer formed on the substrate, the metal layer having an expansion coefficient, during oxidation, that is larger than 1;
an oxide layer formed on the non-oxidized portion of the metal layer;
a plurality of metal oxide nano-pillars grown from the oxide layer, wherein each of the plurality of metal oxide nano-pillars is grown through a plurality of pores defined in a template;
a space defined between adjacent metal oxide nano-pillars; and
a continuous metal oxide cap layer over the plurality of metal oxide nano-pillars and over, but not in, the space between the adjacent metal oxide nano-pillars, the continuous metal oxide cap layer being formed from end portions of the plurality of metal oxide nano-pillars that merge together over a surface of the template, the continuous metal oxide cap layer in contact with all of the metal oxide nano-pillars;
wherein the oxide layer, the plurality of metal oxide nano-pillars, and the metal oxide cap layer are formed from the anodization of portions of the metal layer;
and wherein each of the metal oxide nano-pillars has a diameter ranging from about 10 nm to about 350 nm and a height ranging from about 10 nm to 1000 nm.

10. The nano-structure as defined in claim 9 wherein each of the plurality of metal oxide nano-pillars includes a pitch ranging from about 30 nm to about 500 nm, the height ranging from about 10 nm to about 500 nm, and an aspect ratio that is greater than 10, and wherein a gap between adjacent metal oxide nano-pillars ranges from about 0 nm to about 300 nm.

11. The nano-structure as defined in claim 9 wherein each of the plurality of metal oxide nano-pillars, the continuous metal oxide cap layer, or combinations thereof include a surface modified by a material chosen from aluminum oxide, zirconium oxide, titanium dioxide, silicon dioxide, tungsten oxide, zinc oxide, hafnium oxide, and combinations thereof.

12. The nano-structure as defined in claim 9 wherein the continuous metal oxide cap layer has a thickness that is equal to the space between the adjacent metal oxide nano-pillars.

13. The nano-structure as defined in claim 9 wherein the nano-structure is a micro- or nano-fluidic device.

14. The nano-structure as defined in claim 13 wherein the micro- or nano-fluidic device is for detection of an analyte, or filtration or separation of fluidic media.

15. The nano-structure as defined in claim 9 wherein the non-oxidized portion of the metal layer is tantalum, and wherein the oxide layer, the plurality of metal oxide nano-pillars, and the metal oxide cap layer are tantalum pentoxide.

16. The nano-structure as defined in claim 9 wherein:
the non-oxidized portion of the metal layer is tungsten when the metal layer is tungsten, niobium when the metal layer is niobium, or titanium when the metal layer is titanium; and
the oxide layer, the metal oxide nano-pillars, and metal oxide cap layer are tungsten oxide when the metal layer is tungsten, niobium oxide when the metal layer is niobium, or titanium oxide when the metal layer is titanium.

17. A nano-structure, consisting of:
a substrate;
one tantalum metal layer; and
an oxide structure formed on and from the one tantalum metal layer, the oxide structure including:
an oxide layer;
a plurality of metal oxide nano-pillars formed on the oxide layer, wherein each of the plurality of metal oxide nano-pillars is grown through a plurality of pores defined in a template;
a space defined between adjacent metal oxide nano-pillars; and
a continuous metal oxide cap layer over the plurality of nano-pillars and over, but not in, the space between the adjacent metal oxide nano-pillars, the continuous metal oxide cap layer being formed from end portions of the plurality of metal oxide nano-pillars that merge together over a surface of the template, the continuous metal oxide cap layer in contact with all of the metal oxide nano-pillars;

wherein the oxide layer, the plurality of metal oxide nano-pillars, and the metal oxide cap layer are tantalum pentoxide forme

Assignees

• Mardilovich Peter
• Wei Qingqiao
• Fuller Anthony M
• Hewlett Packard Development Co

Inventors

• Mardilovich Peter
• Wei Qingqiao
• Fuller Anthony M

Classifications

• C25D11/045

  for forming AAO templates · CPC title

• C25D11/02

  Anodisation · CPC title

• Y10T428/24562

  Interlaminar spaces · CPC title

• C25D1/006

  Nanostructures, e.g. using aluminium anodic oxidation templates [AAO] · CPC title

• B81C1/00373 Primary

  Selective deposition, e.g. printing or microcontact printing · CPC title