Lift-off process for GaN films formed on SiC substrates and devices fabricated using the method

1. A method for fabricating a high light extraction photonic device, comprising:

growing a lift-off layer on a substrate, wherein said lift-off layer comprises a material from the group InGaN, AlInGaN and AlInGaAs;

providing an epitaxial semiconductor device structure on said lift-off layer by growing thin doped layers suitable for a resonant cavity light emitting diode, comprising growing a first epitaxial semiconductor layer on said substrate and growing a second epitaxial semiconductor layer on said first epitaxial semiconductor layer, such that said first semiconductor layer is sandwiched between said lift-off layer and said second semiconductor layer, wherein said lift-off layer is sandwiched between said device structure and substrate, said epitaxial semiconductor structure comprising an emitter adapted to emit light in response to a bias;

flip-chip mounting said device structure, lift-off layer and substrate on a submount such that said epitaxial semiconductor device structure is sandwiched between said submount and said lift-off layer, and

separating said substrate from said device structure.

2. A method for removing a silicon carbide substrate from a Group-III nitride epitaxial semiconductor material, comprising:

growing a lift-off layer on a SiC substrate, wherein said lift-off layer comprises a material from the group InGaN, AlInGaN and AlInGaAs;

growing a GaN epitaxial semiconductor device structure on said lift-off layer such that said lift-off layer is sandwiched between said device structure and substrate, said epitaxial semiconductor device structure comprising an emitter adapted to emit light in response to a bias;

flip-chip mounting said device structure, light-off layer and substrate on a submount such that said epitaxial semiconductor device structure is sandwiched between said submount and said lift-off layer; and

removing said lift-off layer using a photo electrochemical etch, to separate said substrate from said device structure.

3. The method of claim 2 , wherein said photo electrochemical etch comprises a solution of KOH and water and a light source having an approximate 400 nanometer (nm) wavelength.

4. A method for removing a silicon carbide substrate from a Group-III nitride epitaxial semiconductor material, comprising:

growing a lift-off layer on a SiC substrate wherein said lift-off layer comprises a material from the group InGaN, AlInGaN and AlInGaAs;

growing a GaN epitaxial semiconductor device structure on said lift-off layer such that said lift-off layer is sandwiched between said device structure and substrate, said epitaxial semiconductor device structure comprising an emitter adapted to emit light in response to a bias;

flip-chip mounting said device structure, lift-off layer and substrate on a submount such that said epitaxial semiconductor device structure is sandwiched between said submount and said lift-off layer; and

removing said lift-off layer by illuminating said lift-off layer with a laser light, to separate said substrate from said device structure.

5. The method of claim 4 , wherein said laser light has a wavelength in the range of approximately 390 and 450 nm.

6. A method for fabricating a high light extraction photonic device, comprising:

growing a lift-off layer on a substrate, wherein said lift-off layer comprises a material from the group InGaN, AlInGaN and AlInGaAs;

providing an epitaxial semiconductor device structure on said lift-off layer such that said lift-off layer is sandwiched between said device structure and substrate, said epitaxial semiconductor structure comprising an emitter adapted to emit light in response to a bias;

flip-chip mounting said device structure, lift-off layer and substrate on a submount such that said epitaxial semiconductor device structure is sandwiched between said submount and said lift-off layer, and

separating said substrate from said device structure by removing said lift-off layer.

7. The method of claim 6 , wherein said lift-off layer comprises a material having a smaller band gap than said substrate and said epitaxial semiconductor device structure.

8. The method of claim 6 , wherein removing said lift-off layer comprises exposing said lift-off layer to a photo electrochemical etch.

9. The method of claim 6 , wherein removing said lift-off layer comprises exposing said lift-off layer to a solution and applying a light source, the combination of said solution and light source causing said lift-off layer to etch without etching the surrounding materials.

10. The method of claim 9 , wherein said solution comprises KOH and water and said light source has an approximate 400 nanometer (nm) wavelength.

11. The method of claim 6 , wherein removing said lift-off layer comprises applying a laser light source to said device that is transparent to said substrate and epitaxial structure, but is absorbed by said lift-off layer.

12. The method of claim 6 , wherein said substrate comprises SiC, said epitaxial structure comprises GaN, wherein removing said lift-off layer comprises illuminating said device with laser light having a wavelength in the range of approximately 390 and 450 nm.

13. The method of claim 12 , wherein said laser light has a wavelength of approximately 400 nm.

14. The method of claim 6 , wherein said epitaxial semiconductor structure comprises a Group-III nitride semiconductor material.

15. The method of claim 6 , wherein said substrate comprises monocrystaline silicon carbide (SiC).

16. The method of claim 6 , wherein providing an epitaxial semiconducting structure comprises:

growing a first epitaxial semiconductor layer on said substrate, and

growing a second epitaxial semiconductor layer on said first epitaxial semiconductor layer, such that said first semiconductor layer is sandwiched between said lift-off layer and said second semiconductor layer.