Methods for fabricating light emitting devices

Patent metadata

Field	Value
Publication number	US-9972974-B1
Application number	US-201715410231-A
Country	US
Kind code	B1
Filing date	Jan 19, 2017
Priority date	Jun 26, 2014
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

In an example, the present invention provides a method for fabricating a light emitting device configured as a Group III-nitride based laser device. The method also includes forming a gallium containing epitaxial material overlying the surface region of a substrate member. The method includes forming a p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a predetermined process condition. The method includes maintaining the predetermined process condition such that an environment surrounding a growth of the p-type (Al,In,Ga)N waveguide material is substantially a molecular N 2 rich gas environment. The method includes maintaining a temperature ranging from 725 C to 925 C during the formation of the p-type (Al,In,Ga)N waveguide material, although there may be variations. In an example, the predetermined process condition is substantially free from molecular H 2 gas.

First claim

What is claimed is:

1. A method for fabricating a light emitting device configured as a Group III-nitride based laser device, the method comprising:
providing a substrate member comprising a gallium and nitrogen containing material and a surface region with a gallium containing epitaxial material overlying the surface region;
forming a p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a predetermined process condition;
maintaining the predetermined process condition such that an environment during a growth of the p-type (Al,In,Ga)N waveguiding material comprises a molecular H 2 to N 2 gas flow ratio of less than 1 to 10; and
maintaining a temperature ranging from 725 C to 925 C during the formation of the p-type (Al,In,Ga)N waveguiding material, wherein the p-type (Al,In,Ga)N waveguiding material is characterized by a carbon impurity concentration of less than 1E17 atoms per cubic centimeter; and
using the device in an application selected from laser display, metrology, communications, health care, and information technology.

2. The method of claim 1 further comprising forming an active region overlying the gallium containing epitaxial material, the active region comprising of a plurality of quantum-well regions, each of the quantum-well regions being configured with a barrier material; and further comprising forming a p-type (Al,In,Ga)N electron blocking layer overlying the active region.

3. The method of claim 1 further comprising forming an active region overlying the gallium containing epitaxial material, the active region comprising of a plurality of quantum-well regions, each of the quantum-well regions being configured with a barrier material; and further comprising forming an n-type waveguiding material underneath the active region.

4. The method of claim 3 wherein the n-type waveguiding material is comprised of a material with a refractive index lower than an average refractive index of the active region but larger than indium gallium nitride with indium nitride alloy composition greater than 2% but less than 15%.

5. The method of claim 4 wherein the n-type waveguiding material comprises an aluminum gallium nitride with aluminum nitride alloy compositions greater than 0% but less than 20%.

6. The method of claim 1 further comprising forming an active region overlying the gallium containing epitaxial material, the active region comprising of a plurality of quantum-well regions, each of the quantum-well regions being configured with a barrier material; wherein the p-type (Al,In,Ga)N waveguiding material overlies the active region; and wherein the p-type (Al,In,Ga)N waveguiding material is comprised of a material with a refractive index lower than an average refractive index of the active region but larger than indium gallium nitride with indium nitride alloy composition greater than 2% but less than 15%.

7. The method of claim 6 wherein the p-type (Al,In,Ga)N waveguiding material comprises aluminum gallium nitride with aluminum nitride alloy compositions greater than 0% but less than 20%.

8. The method of claim 1 further comprising forming an active region overlying the gallium containing epitaxial material, the active region comprising of a plurality of quantum-well regions, each of the quantum-well regions being configured with a barrier material; wherein the active region comprises defect suppression regions.

9. The method of claim 1 wherein the p-type (Al,In,Ga)N waveguiding material has a thickness from 400 to 1000 nanometer with Mg doping level of 5E17 to 2E19 atoms per cubic centimeter, the p-type (Al,In,Ga)N waveguiding material being configured as a waveguiding material and a cladding region.

10. The method of claim 1 further comprising forming a highly Mg doped p++ contact layer with a thickness greater than 5 nanometer but lower than 50 nanometer overlying the p-type (Al,In,Ga)N waveguiding material.

11. The method of claim 1 further comprising introducing a metallorganic or a combination of metallogranic precursors consisting of a group including trimethylgallium, triethylgallium, trimethylaluminum, trimethylindium, or Bis(cyclopentadienyl)magnesium while forming the p-type (Al,In,Ga)N waveguiding material; and wherein the p-type (Al,In,Ga)N waveguiding material is grown using MOCVD or MBE.

12. The method of claim 1 wherein the substrate member is configured on a nonpolar (10-10), (11-20), or a related miscut orientation.

13. The method of claim 1 wherein the substrate member is configured on polar (0001) or (000-1), or a related miscut orientation.

14. The method of claim 1 wherein the substrate member is configured on a semipolar (20-21), (20-2-1), (30-31), (30-3-1), (11-22), or a related miscut orientation.

15. The method of claim 1 wherein the substrate member comprises a misfit dislocation blocking feature.

16. The method of claim 1 further comprising forming a conductive oxide material comprising either an indium tin oxide material or a zinc oxide material overlying the p-type (Al,In,Ga)N waveguiding material; and forming a metallization layer selected from at least one of Au, Ni, Pd, Al, Pt, or Ti overlying the conductive oxide material.

17. The method of claim 1 wherein a diode voltage of the light emitting device is less than 6.75 V at a current density of 14 kA/cm 2 .

18. The method of claim 1 wherein an area on the substrate member affected by dark spot defects is less than 10%.

19. A method for fabricating a light emitting device configured as a Group III-nitride based laser device, the method comprising:
providing a substrate member comprising a gallium and nitrogen containing material and a surface region with a gallium containing epitaxial material overlying the surface region;
forming a first p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a first predetermined process condition;
maintaining the first predetermined process condition such that an environment during a growth of the first p-type (Al,In,Ga)N waveguiding material is substantially molecular N 2 rich gas environment;
maintaining a temperature ranging from 725 C to 925 C during the formation of the first p-type (Al,In,Ga)N waveguiding material; and
forming a second p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a second predetermined process condition, wherein the second predetermined process condition comprises a non-substantially molecular N 2 rich gas environment; and
using the device in an application selected from laser display, metrology, communications, health care, and information technology.

20. A method for fabricating a light emitting device configured as a Group III-nitride based laser device, the method comprising:
providing a substrate member comprising a gallium and nitrogen containing material and a surface region with a gallium containing epitaxial material overlying the surface region;
forming a p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a predetermined process condition;
maintaining the predetermined process condition such that an environment surrounding a growth of the p-type (Al,In,Ga)N waveguiding material is substantially molecular N 2 rich gas environment; and
maintaining a temperature ranging from 725 C to 925 C during the formation of the p-type (Al,In,Ga)N waveguiding material, whereupon the predetermined process condition is substantially free from molecular H 2 gas, the

Assignees

• Soraa Laser Diode Inc

Inventors

• Hsu Po Shan
• Mclaurin Melvin
• Melo Thiago P
• Raring James W

Classifications

• H01S5/320275

  semi-polar orientation · CPC title

• H01S5/3086

  doping of the active layer · CPC title

• H01S5/22

  having a ridge or stripe structure · CPC title

• H01S5/3063

  using Mg · CPC title

• H01S5/3054

  p-doping · CPC title