METHOD FOR PRODUCING GALLIUM NITRIDE SUBSTRATES FOR ELECTRONIC AND OPTOELECTRONIC DEVICES

• US 20130207237A1
• Filed: 10/17/2011
• Published: 08/15/2013
• Est. Priority Date: 10/15/2010
• Status: Abandoned Application

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Weisbuch, Claude C.A., Speck, James S.
• Application Number:
  US13/879,183
• Publication Number:
  US 20130207237A1
• Time in Patent Office: Days
• US Class Current: 257/615
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 33/06 Joining of crystals
• CPC Class Codes: C30B 33/08 Etching
• CPC Class Codes: H01L 21/76259 with separation/delamination along a porous layer
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01S 5/0217 Removal of the substrate
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A method for separating a III-nitride layer from a substrate. This is done by fabricating a detachment porous region between the III-nitride layer and the substrate through etching. The porous region allows for easy detachment of the III-nitride layer from the substrate. Active layers for electronic and optoelectronic devices can then be grown on the III-nitride layer.

Claims

1. A method for separating at least one III-nitride layer from a substrate, comprising:

fabricating a porous region between the III-nitride layer and the substrate through etching; and

separating the III-nitride layer from the substrate at the porous region.

2. The method of claim 1, wherein the substrate is a binary, ternary, or quaternary compound of the III-nitrides materials family.

3. The method of claim 1, wherein one or more active layers are grown on the III-nitride layer.

4. The method of claim 1, wherein the III-nitride layer is a single layer or is comprised of a plurality of sublayers.

5. The method of claim 1, wherein the fabricating step is performed by chemically etching the porous region in a vapor or liquid phase.

6. The method of claim 1, wherein the fabricating step is performed by electrochemically etching the porous region in a liquid phase.

7. The method of claim 6, wherein the chemically etching step is performed by photo-assisted electrochemically etching the porous region in a liquid phase.

8. The method of claim 1, wherein the fabricating step is performed by etching the porous region at a lower porosity.

9. The method of claim 1, wherein the fabricating step is performed by etching the porous region at a higher porosity after etching the etching the porous region at the lower porosity.

10. The method of claim 9, wherein the porous region includes two or more sublayers with different porosities.

11. The method of claim 10, wherein at least one of the sublayers has a higher porosity and is a preferred layer for being separated.

12. The method of claim 10, wherein the sublayers form a distributed Bragg reflector.

13. The method of claim 1, wherein the separating step is performed in situ or ex situ from an etching apparatus.

14. The method of claim 1, wherein the separating step is performed by over-etching the porous region.

15. The method of claim 1, wherein the separating step is performed by applying a mechanical stress to the porous region.

16. The method of claim 1, wherein the separating step is performed by applying a thermal treatment to the porous region.

17. The method of claim 1, wherein the separating step is performed by applying an optically-assisted process to the porous region.

18. The method of claim 1, wherein the III-nitride layers or the porous region are bonded to a substrate before being separated.

19. The method of claim 1, wherein the III-nitride layers or the porous region are bonded to a substrate after being separated.

20. The method of claim 1, further comprising suppressing porosities in the porous region at its surface or within its bulk after being separated.

21. The method of claim 20, wherein the porosities are suppressed by annealing by a thermal or growth treatment or by growth of a buffer layer on the porous region.

22. At least one III-nitride layer separated from a substrate using the method of claim 1.