Method of selective photo-enhanced wet oxidation for nitride layer regrowth on substrates and associated structure

• US 8,809,832 B1
• Filed: 03/07/2013
• Issued: 08/19/2014
• Est. Priority Date: 04/14/2011
• Status: Active Grant

• Current Assignee: Opto Tech Corporation (OptoTech Corp.)
• Original Assignee: Opto Tech Corporation (OptoTech Corp.)
• Inventors: Peng, Lung-Han, Yu, Jeng-Wei, Yeh, Po-Chun
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): Shamsuzzaman, Mohammed
• Application Number:
  US13/788,411
• Publication Number:
  US 20140252308A1
• Time in Patent Office: 530 Days
• Field of Search: 257/13, 257/88, 257/76, 257/615, 257/43, 257/94, 257/98, 438/478, 438/27
• US Class Current: 257/13
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02603 Nanowires
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

Various embodiments of the present disclosure pertain to selective photo-enhanced wet oxidation for nitride layer regrowth on substrates. In one aspect, a method may comprise: forming a first III-nitride layer with a first low bandgap energy on a first surface of a substrate; forming a second III-nitride layer with a first high bandgap energy on the first III-nitride layer; transforming portions of the first III-nitride layer into a plurality of III-oxide stripes by photo-enhanced wet oxidation; forming a plurality of III-nitride nanowires with a second low bandgap energy on the second III-nitride layer between the III-oxide stripes; and selectively transforming at least some of the III-nitride nanowires into III-oxide nanowires by selective photo-enhanced oxidation.

Claims

1. A structure comprising:

a substrate structure;

a first group III-nitride layer with a first low bandgap energy formed on a surface of the substrate;

a second group III-nitride layer with a first high bandgap energy formed on the first group III-nitride layer;

a plurality of group III-oxide stripes formed on the second group III-nitride layer; and

a plurality of group III-oxide nanowires formed on the second group III-nitride layer between the group III-oxide stripes;

wherein at least some of group III-nitride nanowires with a second low bandgap energy formed on the second group III-nitride layer between the group III-oxide stripes are selectively transformed into the group III-oxide nanowires by selective photo-enhanced oxidation; and

wherein the first high bandgap energy is higher than the first low bandgap energy, and the first high bandgap energy is higher than the second low bandgap energy.

2. The structure as recited in claim 1, wherein the selective photo-enhanced oxidation comprises photo-enhanced wet oxidation with a photonic energy between the first high bandgap energy and the first low bandgap energy.

3. The structure as recited in claim 1, wherein the group III-nitride nanowires comprise In/GaN nanowires, and wherein the group III-oxide nanowires comprise (In/Ga)₂O₃ nanowires.

4. The structure as recited in claim 1, wherein the plurality of group III-oxide stripes are formed by transforming portions of the second group III-nitride layer by photo-enhanced oxidation.

5. The structure as recited in claim 1, wherein the substrate comprises a C plane (0001) sapphire substrate, wherein the second group III-nitride layer comprises a layer of AlGaN, and wherein the group III-oxide stripes are aligned substantially parallel to a [11 2 0] or [1 100] direction of GaN.

6. The structure as recited in claim 1, further comprising:

a third group III-nitride layer formed on the group III-oxide stripes and the group III-oxide nanowires.

7. The structure as recited in claim 6, further comprising:

a plurality of group III-nitride layers formed on the third group III-nitride layer to form at least one light-emitting diode (LED).

8. A structure comprising:

a substrate structure;

a plurality of group III-oxide stripes formed on a first surface of the substrate structure;

a plurality of group III-oxide nanowires formed on the first surface of the substrate structure between the III group-oxide stripes; and

a light-emitting diode (LED) structure formed over the group III-oxide stripes and the group III-oxide nanowires;

wherein at least some of group III-nitride nanowires formed on the first surface of the substrate structure between the group III-oxide stripes are treated with selective photo-enhanced oxidation to form the plurality of group III-oxide nanowires.

9. The structure as recited in claim 8, wherein the substrate structure comprises:

a substrate;

a first group III-nitride layer with a first low bandgap energy formed on a surface of the substrate; and

a second group III-nitride layer with a first high bandgap energy formed on the first group III-nitride layer, wherein the first high bandgap energy is higher than the first low bandgap energy;

wherein a surface of second group III-nitride layer is the first surface of the substrate structure.

10. The structure as recited in claim 9, wherein the plurality of group III-oxide stripes are formed by transforming portions of the second group III-nitride layer by photo-enhanced oxidation.

11. The structure as recited in claim 10, wherein the selective photo-enhanced oxidation comprises photo-enhanced wet oxidation with a photonic energy between the first high bandgap energy and the first low bandgap energy.

12. The structure as recited in claim 8, wherein the group III-oxide nanowires are capable of being removed to form a plurality of air gaps.

13. The structure as recited in claim 12, further comprising:

a thermally conductive material filled in the air gaps, and the thermally conductive material comprising a plurality of nanoparticles, a plurality of compound particles, or a combination thereof.

14. The structure as recited in claim 12, further comprising:

an electrically conductive material filled in the air gaps, and the electrically conductive material comprising a plurality of nanoparticles, a plurality of compound particles, or a combination thereof.