Structure and method for fabricating GaN substrates from trench patterned GaN layers on sapphire substrates

• US 6,617,261 B2
• Filed: 12/18/2001
• Issued: 09/09/2003
• Est. Priority Date: 12/18/2001
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Wong, William S., Biegelsen, David K., Kneissl, Michael A.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): LE, THAO P
• Application Number:
  US10/017,599
• Publication Number:
  US 20030114017A1
• Time in Patent Office: 630 Days
• Field of Search: 438/778, 438/459, 438/460, 438/478
• US Class Current: 438/778
• 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 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68363 used in a transfer process involving transfer directly from an origin substrate to a target substrate without use of an intermediate handle substrate
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/0216 using an intermediate compound, e.g. a glue or solder
• CPC Class Codes: H01S 5/0217 Removal of the substrate

Abstract

Gallium nitride substrates are formed by etching a gallium nitride layer on a sapphire substrate or by selective area regrowth of a gallium nitride layer first deposited onto a sapphire substrate. The gallium nitride layers are bonded to a support substrate and a laser pulse directed through the transparent sapphire detaches the gallium nitride layers from the sapphire substrate. The gallium nitride layers are then detached from the support substrate forming freestanding gallium nitride substrates.

Claims

1. A method for making a gallium nitride substrate for a nitride based semiconductor structure comprising the steps of:

depositing a gallium nitride layer on a sapphire substrate;

etching at least one trench through said gallium nitride layer to said sapphire substrate, said at least one trench dividing said gallium nitride layer into a plurality of gallium nitride substrates;

attaching a support substrate to a side of said plurality of gallium nitride substrates opposite said sapphire substrate;

removing said sapphire substrate from said plurality of gallium nitride substrates; and

removing said support substrate from said plurality of gallium nitride substrates.

2. The method of claim 1 wherein the step of attaching said support substrate to said side of said plurality of gallium nitride substrates includes using glue to attach said support substrate to said plurality of gallium nitride substrates.

3. The method of claim 1 wherein the step of removing said sapphire substrate includes exposing said sapphire substrate to laser light.

4. The method of claim 3 wherein the step of removing said sapphire substrate includes polishing of said sapphire substrate prior to exposure to laser light.

5. The method of claim 1 wherein said support substrate includes a material selected from the group consisting of silicon and gallium arsenide or other rigid support material.

6. The method of claim 1 further comprising the step of

patterning said gallium nitride layer after deposition of said gallium nitride layer on said sapphire substrate, said plurality of gallium nitride substrates formed underneath said patterning, said etching occurring between said patterning.

11. The method of claim 1 wherein said support substrate includes a material selected from the group consisting of silicon and gallium arsenide or other rigid supporting material.

7. A method for making a gallium nitride substrate for a nitride based semiconductor structure comprising the steps of:

depositing a first gallium nitride layer on a sapphire substrate;

patterning said first gallium nitride layer,

depositing a second gallium nitride layer on said first gallium nitride layer through opening in said patterning, said second gallium nitride layer overgrowing said patterning to form at least one trench through said second gallium nitride layer to said sapphire substrate, said at least one trench dividing said second gallium nitride layer into a plurality of gallium nitride substrates;

attaching a support substrate to a side of said plurality of gallium nitride substrates opposite said sapphire substrate;

removing said sapphire substrate from said plurality of gallium nitride substrates; and

removing said support substrate from said plurality of gallium nitride substrates.

8. The method of claim 7 wherein the step of attaching said support substrate to said side of said plurality of gallium nitride substrates includes using glue to attach said support substrate to said plurality of gallium nitride substrates.

9. The method of claim 7 wherein the step of removing said sapphire substrate includes exposing said sapphire substrate to laser light.

10. The method of claim 9 wherein the step of removing said sapphire substrate includes polishing of said sapphire substrate prior to exposure to laser light.