Methods of fabricating micro- and nanostructure arrays and structures formed therefrom

Patent metadata

Field	Value
Publication number	US-9627199-B2
Application number	US-201414568576-A
Country	US
Kind code	B2
Filing date	Dec 12, 2014
Priority date	Dec 13, 2013
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

Methods of fabricating micro- and nanostructures comprise top-down etching of lithographically patterned GaN layer to form an array of micro- or nanopillar structures, followed by selective growth of GaN shells over the pillar structures via selective epitaxy. Also provided are methods of forming micro- and nanodisk structures and microstructures formed from thereby.

First claim

What is claimed is:

1. A method of fabricating an array of microstructures, comprising the steps of:
providing an epilayer of gallium nitride (GaN) grown on a substrate;
etching an array of GaN pillars in said epilayer; and
growing GaN shells on said etched array of GaN pillars to form core-shell structures via selective epitaxy, wherein a first portion of said GaN shells are doped with a first material, and a second portion of said GaN shells are doped with a second material different than said first material.

2. The method of claim 1 , wherein said substrate comprises a material selected from the group consisting of sapphire, silicon, gallium arsenide, and silicon carbide.

3. The method of claim 1 , wherein said substrate further comprises a buffer layer intermediate a base layer and said GaN epilayer.

4. The method of claim 3 , wherein said buffer layer comprises at least one of aluminum nitride (AlN) and aluminum gallium nitride (AlGaN).

5. The method of claim 1 , wherein a least a portion of said GaN pillars are doped with silicon, magnesium, zinc, or iron.

6. The method of claim 1 , wherein at least a portion of said GaN shells are doped with silicon, magnesium, zinc, or iron.

7. The method of claim 1 , wherein said first portion of said GaN shells have a first chemical composition, and said second portion of said GaN shells have a second chemical composition different than said first chemical composition.

8. The method of claim 7 , wherein said first and second portions of said GaN shells are sequentially grown on said etched array of GaN pillars.

9. The method of claim 1 , wherein said etching step comprises inductively coupled plasma (ICP) etching.

10. The method of claim 9 , comprising the further step of chemically etching said ICP etched array of pillars.

11. The method of claim 10 , wherein said chemically etching step comprises hot phosphoric acid etching.

12. The method of claim 10 , wherein said chemically etching step comprises etching in a solution comprising potassium hydroxide (KOH).

13. The method of claim 1 , wherein said selective epitaxy is hydride vapor phase epitaxy (HVPE).

14. The method of claim 13 , wherein said HVPE utilizes at least one of ammonia, nitrogen, or hydrogen chloride gas.

15. The method of claim 13 , wherein said HVPE is conducted at a temperature of between about 850° C. and about 1150° C.

16. The method of claim 13 , wherein said HVPE is conducted at a pressure between about 10 Torr and about 760 Torr.

17. The method of claim 1 , wherein said core-shell structures have inclined {1-101} sidewalls.

18. The method of claim 1 , wherein said core-shell structures have vertical {1-100} sidewalls.

Assignees

• Univ Maryland
• Northrop Grumman Systems Corp
• Us Commerce
• The Us Secretary Of Commerce Nat Inst Of Standards And Tech

Inventors

• Motayed Abhishek
• Krylyuk Sergiy
• Davydov Albert V
• King Matthew
• Ha Jong-Yoon

Classifications

• H10P50/648

  Anisotropic liquid etching · CPC title

• H10P50/646

  of Group III-V materials · CPC title

• H10P50/246

  of Group III-V materials · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10P14/2901

  Materials · CPC title