GaN-based semiconductor light-emitting device and method for the fabrication thereof

1. A GaN-based semiconductor light-emitting device comprising:

a stacked body having an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer, each formed of a GaN-based semiconductor, sequentially stacked and provided with a first bonding layer made of metal as an outermost layer of the stacked body;

an electroconductive substrate; and

a second bonding layer formed on the electroconductive substrate and bonded to a bonding surface of the first bonding layer,

wherein the bonding surface is opposite a side of the second bonding layer on which the electroconductive substrate is formed, and wherein the second bonding layer is made of a metal of a same crystal structure as the first bonding layer, and allowed to exhibit an identical crystal orientation both in a perpendicular direction of the bonding surface and in an in-plane direction of the bonding surface, and wherein the first bonding layer and the second bonding layer possess a face centered cubic structure and exhibit a crystal orientation of (111) in the perpendicular direction of the bonding surface.

2. A GaN-based semiconductor light-emitting device according to claim 1 , further comprising a lattice-matching layer formed between the electroconductive substrate and the second bonding layer.

3. A GaN-based semiconductor light-emitting device according to claim 2 , wherein the lattice-matching layer is made of a simple metal of any one member or a metal alloy of two or more members selected from the group consisting of Hf, Mg and Zr.

4. A GaN-based semiconductor light-emitting device according to claim 1 , wherein the first bonding layer and the second bonding layer are each formed of any one of Au, Ag, Cu, Pt, Pd, Rh, Cu and Ir.

5. A GaN-based semiconductor light-emitting device according to claim 4 , wherein the first bonding layer and the second bonding layer are each formed of Au or an Au alloy.

6. A GaN-based semiconductor light-emitting device according to claim 1 , wherein the first bonding layer and the second bonding layer have a difference within 5% in lattice constant.

7. A GaN-based semiconductor light-emitting device according to claim 1 , wherein the electroconductive substrate is a single-crystal silicon substrate.

8. A GaN-based semiconductor light-emitting device according to claim 7 , wherein the electroconductive substrate is a single-crystal silicon substrate and possesses a (111) face as a substrate surface.

9. A GaN-based semiconductor light-emitting device according to claim 8 , wherein the second bonding layer is directly deposited on the (111) face of the single-crystal silicon substrate.

10. A GaN-based semiconductor light-emitting device according to claim 8 , further comprising an orientation adjusting layer formed between the single-crystal silicon substrate and the second bonding layer.

11. A GaN-based semiconductor light-emitting device according to claim 10 , wherein the orientation adjusting layer is formed of Ag or an Ag alloy.

12. A method for the fabrication of a GaN-based semiconductor light-emitting device, comprising the steps of:

forming on a substrate a first stacked body having sequentially stacked at least an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer each formed of a GaN-based semiconductor and having a first bonding layer made of metal as an uppermost layer of the stacked body;

forming on an electroconductive substrate a second stacked body possessing a second bonding layer made of a metal of a same crystal structure as the first bonding layer and exhibiting an identical crystal orientation in both a perpendicular direction of a bonding surface and an in-plane direction of the bonding surface;

integrating the first stacked body and the second stacked body by mutual bonding; and

removing the substrate from the first stacked body, wherein the first bonding layer and the second bonding layer possess a face centered cubic structure and exhibit a crystal orientation of (111) in the perpendicular direction of the bonding surface.

13. A. method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 12 , wherein the mutual bonding is implemented by irradiating bonding surfaces of the bonding layers in vacuum with an inert gas ion beam or an inert gas neutral atom beam.

14. A method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 12 , wherein the substrate is made of sapphire.

15. A method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 12 , wherein the electroconductive substrate is a single crystal silicon substrate and possessing a (111) face as a substrate surface and, when the second bonding layer has a face-centered cubic structure (111) face of Au, Ag, Cu, Pt, Pd, Rh, Cu or Ir or a hexagonal closest packing (0001) face of Ru or Re, the substrate surface is cleaned by RCA cleaning and then subjected to hydrogen termination with dilute hydrofluoric acid, and thereafter the second bonding layer is formed using a film-depositing device provided with vacuum.

16. A method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 15 , wherein the vacuum is under pressure of less than 1.0 × 10 −4 Pa.

17. A GaN-based semiconductor light-emitting device comprising:

a stacked body having an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer, each formed of a GaN-based semiconductor, sequentially stacked and provided with a first bonding layer made of metal as an outermost layer of the stacked body;

an electroconductive substrate; and

a second bonding layer formed on the electroconductive substrate and bonded to a bonding surface of the first bonding layer, wherein the bonding surface is opposite a side of the second bonding layer on which the electroconductive substrate is formed, wherein the second bonding layer is made of a metal of a same crystal structure as the first bonding layer, and allowed to exhibit an identical crystal orientation both in a perpendicular direction of the bonding surface and in an in-plane direction of the bonding surface, and wherein the first bonding layer and the second bonding layer each has a hexagonal closest packing structure and a crystal orientation of (0001) in the perpendicular direction of the bonding surface.

18. A GaN-based semiconductor light-emitting device according to claim 17 , wherein the first bonding layer and the second bonding layer are each formed of Ru or Re.

19. A method for the fabrication of a GaN-based semiconductor light-emitting device, comprising the steps of:

forming on a substrate a first stacked body having sequentially stacked at least an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer each formed of a GaN-based semiconductor and having a first bonding layer made of metal as an uppermost layer of the stacked body;

forming on an electroconductive substrate a second stacked body possessing a second bonding layer made of a metal of a same crystal structure as the first bonding layer and exhibiting an identical crystal orientation in both a perpendicular direction of a bonding surface and an in-plane direction of the bonding surface;

integrating the first stacked body and the second stacked body by mutual bonding; and

removing the substrate from the first stacked body, wherein the first bonding layer and the second bonding layer each has a hexagonal closest packing structure and a crystal orientation of (0001) in the perpendicular direction of the bonding surface.

20. A. method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 19 , wherein the mutual bonding is implemented by irradiating bonding surfaces of the bonding layers in vacuum with an inert gas ion beam or an inert gas neutral atom beam.

21. A method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 19 , wherein the substrate is made of sapphire.

22. A method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 19 , wherein the electroconductive substrate is a single crystal silicon substrate and possessing a (111) face as a substrate surface and, when the second bonding layer has a face-centered cubic structure (111) face of Au, Ag, Cu, Pt, Pd, Rh, Cu or Ir or a hexagonal closest packing (0001) face of Ru or Re, the substrate surface is cleaned by RCA cleaning and then subjected to hydrogen termination with dilute hydrofluoric acid, and thereafter the second bonding layer is formed using a film-depositing device provided with vacuum.

23. A method for the fabrication of a GaN-based semiconductor light-emitting device according to claim 22 , wherein the vacuum is under a pressure of less than 1.0× 10 −4 Pa.

24. A method for the fabrication of a GaN-based semiconductor light-emitting device, comprising the steps of:

forming on a substrate a first stacked body having sequentially stacked at least an n-type semiconductor layer, a light-emitting layer and a p-type semiconductor layer each formed of a GaN-based semiconductor and having a first bonding layer made of metal as an uppermost layer of the stacked body;

forming on an electroconductive substrate a second stacked body possessing a second bonding layer made of a metal of a same crystal structure as the first bonding layer and exhibiting an identical crystal orientation in both a perpendicular direction of a bonding surface and an in-plane direction of the bonding surface;

forming a lattice-matching layer formed between the electroconductive substrate and the second bonding layer;

integrating the first stacked body and the second stacked body by mutual bonding; and

removing the substrate from the first stacked body, wherein the lattice-matching layer is made of a simple metal of any one member or a metal alloy of two or more members selected from the group consisting of Hf, Mg and Zr.