Optical device structure using GaN substrates and growth structures for laser applications

1. A method for manufacturing an optical device, the method comprising:

providing a gallium and nitrogen containing substrate member having a semipolar crystalline surface region, the gallium and nitrogen containing substrate member having a thickness of less than 500 microns, the gallium and nitrogen containing substrate member characterized by a dislocation density of less than 10 7 cm −2 , the semipolar crystalline surface region having a root mean square surface roughness of 10 nm or less over a 5 micron by 5 micron analysis area, the semipolar crystalline surface region being characterized by a specified off-set from a (20-21) semipolar plane;

forming a surface reconstruction region overlying the semipolar crystalline surface region, the surface reconstruction region having an oxygen bearing concentration of greater than 1E17 cm −3 ;

forming an n-type cladding layer comprising a first quaternary alloy, the first quaternary alloy comprising an aluminum bearing species, an indium bearing species, a gallium bearing species, and a nitrogen bearing species overlying the semipolar crystalline surface region, the n-type cladding layer having a thickness from 100 nm to 4000 nm with an n-type doping level of 1E17 cm −3 to 6E18 cm −3 ;

forming a first gallium and nitrogen containing epitaxial material comprising a first portion characterized by a first indium concentration, a second portion characterized by a second indium concentration, and a third portion characterized by a third indium concentration overlying the n-type cladding layer;

forming an n-side separate confining heterostructure (SCH) waveguiding layer overlying the n-type cladding layer, the n-side SCH waveguiding layer comprising InGaN with a molar fraction of InN of between 1% and 8% and having a thickness from 30 nm to 150 nm;

forming a multiple quantum well active region overlying the n-side SCH waveguiding layer, the multiple quantum well active region comprising two to five InGaN quantum wells having a thickness from 2.0 nm to 4.5 nm and being separated by gallium and nitrogen containing barrier layers having a thickness from 7.5 nm to 18 nm;

forming a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprised of GaN or InGaN and having a thickness from 20 nm to 100 nm, the InGaN having a molar fraction of InN of between 1% and 5%;

forming a second gallium and nitrogen containing material overlying the p-side guide layer;

forming a p-type cladding layer comprising a second quaternary alloy overlying the second gallium and nitrogen containing material, the p-type cladding layer having a thickness from 300 nm to 1000 nm with a magnesium doping level of 1E17 cm −3 to 3E19 cm −3 ;

causing formation of a plurality of hydrogen species, the plurality of hydrogen species spatially disposed within the p-type cladding layer; and

forming a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 100 nm and a magnesium doping level of 2E19 cm −3 to 1E22 cm −3 ;

forming a waveguide member using an etching process, the waveguide member being aligned substantially in a projection of the c-direction, the waveguide member comprising a first end and a second end, the waveguide member having a first edge region formed on a first side of the waveguide member, the waveguide member having a second edge region formed on a second side of the waveguide member;

maintaining the etching process from causing any damage to the multiple quantum well active region;

forming a first facet on the first end, the first facet being characterized by a first semipolar characteristic; and

forming a second facet on the second end, the second facet being characterized by a second semipolar characteristic;

whereupon the waveguide member is provided between the first facet and the second facet, the waveguide member having a length of greater than 300 microns and configured to emit substantially polarized electromagnetic radiation such that a polarization is substantially orthogonal to the waveguide member direction and the polarized electromagnetic radiation having a wavelength of 500 nm and greater and a spontaneous emission spectral full width at half maximum of less than 50 nm in a light emitting diode mode of operation.

2. The method of claim 1 wherein the semipolar crystalline surface region is characterized by an off-set of +/−3 degrees from the (20-21) semipolar plane toward a c-plane.

3. The method of claim 1 wherein the forming the surface reconstruction region overlying the semipolar crystalline surface region comprises heating the gallium and nitrogen containing substrate member to above 1000° C. with an ammonia and hydrogen over pressure.

4. The method of claim 1 wherein the forming the n-type cladding layer comprises introducing gaseous species of at least ammonia with nitrogen or hydrogen and an n-type dopant bearing species.

5. The method of claim 1 wherein the forming the n-type cladding layer comprises using silicon as the n-type dopant.

6. The method of claim 1 wherein the first gallium and nitrogen containing epitaxial material comprises n-type GaN and underlies the n-type cladding layer.

7. The method of claim 1 wherein the forming the n-side SCH waveguiding layer comprises processing at a deposition rate of less than 1.5 angstroms per second and an oxygen concentration of less than 8E17 cm −3 .

8. The method of claim 1 wherein the forming the multiple quantum well active region comprises processing at a deposition rate of less than 1 angstroms per second and an oxygen concentration of less than 8E17 cm −3 .

9. The method of claim 1 wherein the forming the p-side guide layer overlying the multiple quantum well active region comprises depositing an InGaN SCH layer with an InN molar fraction of between 1% and 5% and a thickness ranging from 10 nm to 100 nm.

10. The method of claim 1 wherein the forming the second gallium and nitrogen containing material overlying the p-side guide layer comprises depositing a p-type GaN guide layer with a thickness ranging from 50 nm to 300 nm.

11. The method of claim 1 further comprising an electron blocking layer overlying the p-side guide layer, the electron blocking layer comprising AlGaN with a molar fraction of AlN of between 6% and 22% and having a thickness from 5 nm to 25 nm and doped with a p-type dopant such as magnesium.

12. The method of claim 1 wherein the p-type cladding layer comprises a hydrogen species that has a concentration that tracks relatively with the p-type dopant concentration.

13. The method of claim 1 wherein the forming a p++-gallium and nitrogen containing contact layer comprises depositing a GaN material formed with a growth rate of less than 2.5 angstroms per second and characterized by a magnesium concentration of greater than 1E20 cm −3 .

14. The method of claim 1 wherein the etching process for forming the waveguide member comprises using a dry etch technique to etch to a depth that does not penetrate through the multiple quantum well active region to maintain the multiple quantum well active region substantially free from damage.

15. The method of claim 1 wherein forming the first facet on the first end and forming the second facet on the second end comprises using a scribing and breaking process.

16. A method for fabricating a laser device, the method comprising:

providing a gallium and nitrogen containing substrate member having a semipolar crystalline surface region, the gallium and nitrogen containing substrate member having a thickness of less than 500 microns, the gallium and nitrogen containing substrate member characterized by a dislocation density of less than 10 7 cm −2 , the semipolar crystalline surface region having a root mean square surface roughness over a 5 micron by 5 micron analysis area, the semipolar crystalline surface region being characterized by an offcut;

forming a gallium and nitrogen containing n-type cladding layer overlying the semipolar crystalline surface region, the gallium and nitrogen containing n-type cladding layer having a thickness from 300 nm to 6000 nm with an n-type doping level of 1E17 cm −3 to 3E18 cm −3 ;

forming an n-side separate confining heterostructure (SCH) waveguide layer overlying the gallium and nitrogen containing n-type cladding layer, the n-side SCH waveguide layer comprised of at least gallium, indium, and nitrogen with molar fraction of InN of between 1% and 8% and having a thickness from 20 nm to 150 nm;

forming a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five InGaN quantum wells having a thickness from 2.0 nm to 4.5 nm and being separated by gallium and nitrogen containing barrier layers;

forming a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprised of GaN or InGaN and having a thickness from 10 nm to 120 nm;

forming a p-type gallium and nitrogen containing cladding layer overlying the multiple quantum well active region, the p-type gallium and nitrogen containing cladding layer having a thickness from 300 nm to 1000 nm with a p-type doping level of 1E17 cm −3 to 5E19 cm −3 ;

forming a p++ gallium and nitrogen containing contact layer overlying the p-type gallium and nitrogen containing cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 120 nm with a p-type doping level of 1E19 cm −3 to 1E22 cm −3 ;

forming a waveguide member, the waveguide member being aligned substantially in a projection of the c-direction, the waveguide member comprising a first end and a second end;

forming a first facet formed on the first end; and

forming a second facet formed on the second end.

17. The method of claim 16 wherein the gallium and nitrogen containing n-type cladding layer comprises n-type AlGaN.

18. The method of claim 16 wherein the gallium and nitrogen containing n-type cladding layer comprises n-type InAlGaN.

19. The method of claim 16 wherein the p-type gallium and nitrogen containing cladding layer comprises p-type AlGaN.

20. The method of claim 16 wherein the p-type gallium and nitrogen containing cladding layer comprises p-type InAlGaN.

21. The method of claim 16 wherein the gallium and nitrogen containing barrier layers comprise GaN and/or AlGaN.

22. The method of claim 16 wherein the first facet includes a semipolar characteristic.

23. The method of claim 16 wherein the second facet includes a semipolar characteristic.

24. The method of claim 16 wherein the semipolar crystalline surface region is characterized by an off-set of +/−3 degrees from a (20-21) semipolar plane toward a c-plane.

25. The method of claim 16 further comprising forming an electron blocking layer overlying the p-side guide layer, the electron blocking layer comprising AlGaN with a molar fraction of AlN of between 6% and 22% and having a thickness from 5 nm to 25 nm and doped with magnesium.

26. A method for manufacturing an optical device, the method comprising:

providing a gallium and nitrogen containing substrate member having a semipolar crystalline surface region, the gallium and nitrogen containing substrate member having a thickness of less than 450 microns, the gallium and nitrogen containing substrate member characterized by a dislocation density of less than 10 7 cm −2 , the semipolar crystalline surface region having a root mean square surface roughness over a 5 micron by 5 micron analysis area;

forming an offcut characterizing the semipolar crystalline surface region;

forming an n-type cladding layer comprising at least an aluminum bearing species, a gallium bearing species, and a nitrogen bearing species overlying the semipolar crystalline surface region, the n-type cladding layer having a thickness from 100 nm to 5000 nm with an n-type doping level of 1E17 cm −3 to 6E18 cm −3 ;

forming a first gallium and nitrogen containing epitaxial material comprising a first portion including a first indium concentration, a second portion including a second indium concentration, and a third portion including a third indium concentration overlying the n-type cladding layer;

forming an n-side separate confining heterostructure (SCH) waveguide layer overlying the n-type cladding layer, the n-side SCH waveguide layer comprising InGaN with a molar fraction of InN of between 1% and 8% and having a thickness from 30 nm to 150 nm;

forming a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five InGaN quantum wells having a thickness from 2.0 nm to 4.5 nm and being separated by gallium and nitrogen containing barrier layers having a thickness from 5.5 nm to 18 nm;

forming a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprised of GaN or InGaN and having a thickness from 20 nm to 100 nm;

forming a p-type cladding layer comprising at least an aluminum bearing species, a gallium bearing species, and a nitrogen bearing species overlying the p-side guide layer, the p-type cladding layer having a thickness from 250 nm to 1000 nm with a p-type doping level of 1E17 cm −3 to 5E19 cm −3 ;

forming a plurality of hydrogen species, the plurality of hydrogen species spatially disposed within the p-type cladding layer;

forming a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 100 nm with a p-type doping level of 1E19 cm −3 to 1E22 cm −3 ;

forming a waveguide member, the waveguide member being aligned substantially in a projection of the c-direction, the waveguide member comprising a first end and a second end;

forming a first facet formed on the first end such that a first semipolar characteristic configured on the first facet;

forming a second facet formed on the second end such that a second semipolar characteristic configured on the second facet;

forming a first edge region formed on a first side of the waveguide member such that a first etched surface formed on the first edge region;

forming a second edge region formed on a second side of the waveguide member such that a second etched surface formed on the second edge region;

whereupon the waveguide member is provided between the first facet and the second facet, the waveguide member having a length of greater than 300 microns and configured to emit substantially polarized electromagnetic radiation such that a polarization is substantially orthogonal to a waveguide cavity direction and the substantially polarized electromagnetic radiation having a wavelength of 500 nm and greater and a spontaneous emission spectral full width at half maximum of less than 50 nm in a light emitting diode mode of operation.

27. The method of claim 26 wherein the n-type cladding layer comprises n-type AlGaN.

28. The method of claim 26 wherein the n-type cladding layer comprises n-type InAlGaN.

29. The method of claim 26 wherein the p-type cladding layer comprises p-type AlGaN.

30. The method of claim 26 wherein the p-type cladding layer comprises p-type InAlGaN.

31. The method of claim 26 wherein the gallium and nitrogen containing barrier layers comprise GaN and/or AlGaN.

32. The method of claim 26 wherein the semipolar crystalline surface region is characterized by an off-set of +/−3 degrees from a (20-21) semipolar plane toward a c-plane.

33. A method for fabricating an optical device comprising:

providing a gallium and nitrogen containing substrate member having a semipolar crystalline surface region, the gallium and nitrogen containing substrate member having a thickness of less than 500 microns, the gallium and nitrogen containing substrate member characterized by a dislocation density of less than 10 7 cm 2 , the semipolar crystalline surface region having a root mean square surface roughness of 10 nm or less over a 5 micron by 5 micron analysis area;

forming an offcut characterizing the semipolar crystalline surface region;

forming an n-type cladding layer comprising a first quaternary alloy, the first quaternary alloy comprising an aluminum bearing species, an indium bearing species, a gallium bearing species, and a nitrogen bearing species overlying the semipolar crystalline surface region, the n-type cladding layer having a thickness from 100 nm to 5000 nm with an n-type doping level of 1E17 cm −3 to 6E18 cm −3 ;

forming a surface reconstruction region overlying the semipolar crystalline surface region and the n-type cladding layer and at an interface within a vicinity of the semipolar crystalline surface region, the surface reconstruction region having an oxygen bearing concentration of greater than 1E17 cm −3 ;

forming a first gallium and nitrogen containing material comprising a first portion including a first indium concentration, a second portion including a second indium concentration, and a third portion including a third indium concentration overlying the n-type cladding layer;

forming an n-side separate confining heterostructure (SCH) waveguide layer overlying the n-type cladding layer, the n-side SCH waveguide layer comprised of InGaN with molar fraction of InN of between 1% and 8% and having a thickness from 30 nm to 150 nm;

forming a multiple quantum well active region overlying the n-side SCH waveguide layer, the multiple quantum well active region comprising two to five InGaN quantum wells having a thickness from 2.0 nm to 4.5 nm and being separated by gallium and nitrogen containing barrier layers having a thickness from 5 nm to 20 nm;

forming a p-side guide layer overlying the multiple quantum well active region, the p-side guide layer comprising GaN or InGaN and having a thickness from 20 nm to 100 nm;

forming a second gallium and nitrogen containing material overlying the p-side guide layer;

forming a p-type cladding layer comprising a second quaternary alloy overlying the second gallium and nitrogen containing material, the p-type cladding layer having a thickness from 250 nm to 1000 nm and comprising a p-type doping species including magnesium at a concentration of 1E17 cm −3 to 4E19 cm −3 ;

forming a plurality of hydrogen species, the plurality of hydrogen species spatially disposed within the p-type cladding layer;

forming a p++ gallium and nitrogen containing contact layer overlying the p-type cladding layer, the p++ gallium and nitrogen containing contact layer having a thickness from 10 nm to 140 nm and comprising a p-type doping species including magnesium at a concentration of 1E19 cm −3 to 1E22 cm −3 ;

forming a waveguide member, the waveguide member being aligned substantially in a projection of the c-direction, the waveguide member comprising a first end and a second end;

whereupon a first facet formed on the first end, a first semipolar characteristic configured on the first facet, a second facet formed on the second end, a second semipolar characteristic configured on the second facet, a first edge region formed on a first side of the waveguide member, a first etched surface formed on the first edge region, a second edge region formed on a second side of the waveguide member, and a second etched surface formed on the second edge region; and

whereupon the waveguide member is provided between the first facet and the second facet, the waveguide member having a length of greater than 300 microns and configured to emit substantially polarized electromagnetic radiation such that a polarization is substantially orthogonal to a waveguide cavity direction and the substantially polarized electromagnetic radiation having a wavelength of 500 nm and greater and a spontaneous emission spectral full width at half maximum of less than 50 nm in a light emitting diode mode of operation or a spectral line-width of a laser output of greater than 0.4 nm.