Epitaxial growth of cladding regions for a gallium and nitrogen containing laser diode
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.
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 having a surface region and a gallium containing epitaxial material overlying the surface region;
forming an n-type (Al,In,Ga)N cladding material overlying the gallium containing epitaxial material, the n-type (Al,In,Ga)N cladding material grown under H 2 or N 2 rich ambient conditions;
forming an active region overlying the n-type (Al,In,Ga)N cladding 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
forming a p-type (Al,In,Ga)N cladding material overlying the active region, the p-type (Al,In,Ga)N cladding material grown under a predetermined process condition such that an environment during a growth of the p-type (Al,In,Ga)N cladding material comprises a molecular H 2 to N 2 gas flow ratio of less than 1 to 10, wherein the p-type (Al,In,Ga)N cladding material is characterized by a carbon concentration of less than 1E17 atoms per cubic centimeter.
2. The method of claim 1 further comprising forming a p-type (Al,In,Ga)N electron blocking layer overlying the active region.
3. The method of claim 1 wherein the n-type (Al,In,Ga)N cladding material is comprised of a material with a refractive index lower than an average refractive index of the active region.
4. The method of claim 1 wherein the n-type (Al,In,Ga)N cladding material comprises aluminum gallium nitride with aluminum nitride alloy compositions greater than 0% but less than 20%.
5. The method of claim 1 wherein the p-type (Al,In,Ga)N cladding material is comprised of a material with a refractive index lower than an average refractive index of the active region.
6. The method of claim 1 wherein the p-type (Al,In,Ga)N cladding material comprises aluminum gallium nitride with aluminum nitride alloy compositions greater than 0% but less than 20%.
7. The method of claim 1 wherein the p-type (Al,In,Ga)N cladding material has a thickness from 400 to 1000 nanometer with Mg doping level of 5E17 to 2E19 atoms per cubic centimeter.
8. 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 cladding material.
9. The method of claim 1 further comprising introducing a metallorganic precursor consisting of a group including trimethylgallium, triethylgallium, trimethylaluminum, trimethylindium, or Bis(cyclopentadienyl)magnesium while forming the p-type (Al,In,Ga)N cladding material; and wherein the p-type (Al,In,Ga)N cladding material is grown using a metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) process.
10. The method of claim 1 wherein the substrate member has a nonpolar (10-10), (11-20), or a related miscut orientation.
11. The method of claim 1 wherein the substrate member has a polar (0001), (000-1), or a related miscut orientation.
12. The method of claim 1 wherein the substrate member has a semipolar (20-21), (20-2-1), (30-31), (30-3-1), (11-22), or a related miscut orientation.
13. The method of claim 1 wherein the substrate member comprises a misfit dislocation blocking feature.
14. 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 cladding material; and forming a metallization layer selected from at least one of Au, Ni, Pd, Al, Pt, or Ti overlying the conductive oxide material.
15. 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 .
16. The method of claim 1 wherein an area on the substrate member affected by dark spot defects is less than 10%.
17. A method for fabricating a light emitting device configured as a Group III-nitride based laser device, the method comprising:
providing a substrate member having a surface region and a gallium containing epitaxial material overlying the surface region;
placing the substrate member into a reactor, and while the substrate member is in the reactor:
forming an n-type (Al,In,Ga)N cladding material overlying the gallium containing epitaxial material, the n-type (Al,In,Ga)N cladding material grown under H 2 or N 2 rich ambient conditions;
forming an active region overlying the n-type (Al,In,Ga)N cladding material, the active region comprising of a plurality of quantum-well regions, each of the quantum-well regions being configured with a barrier material;
forming a p-type (Al,In,Ga)N cladding material overlying the active region, the p-type (Al,In,Ga)N cladding material formed under a first predetermined process condition such that an environment during growth of the p-type (Al,In,Ga)N cladding material is substantially molecular N 2 rich gas and a temperature ranges from 700 C to 950 C during the formation of the p-type (Al,In,Ga)N cladding material; and
forming a Mg doped (Al,In,Ga)N material overlying the p-type (Al,In,Ga)N cladding material.
18. A method for fabricating a light emitting device configured as a Group III-nitride based laser device, the method comprising:
providing a substrate member having a surface region and a gallium containing epitaxial material overlying the surface region;
forming an n-type (Al,In,Ga)N cladding material overlying the gallium containing epitaxial material, the n-type (Al,In,Ga)N cladding material grown under H 2 or N 2 rich ambient conditions;
forming an active region overlying the n-type (Al,In,Ga)N cladding 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
forming a p-type (Al,In,Ga)N cladding material overlying the active region, the p-type (Al,In,Ga)N cladding material formed under a predetermined process condition such that an environment during growth of the p-type (Al,In,Ga)N cladding material is substantially molecular N 2 rich gas that is substantially free from molecular H 2 gas, wherein the p-type (Al,In,Ga)N cladding material is formed using a trimethylgallium metallorganic precursor and/or a triethylgallium metallorganic precursor; the predetermined process condition includes an ammonia containing species, and a ratio of the ammonia containing species to the substantially molecular N 2 rich gas environment is greater than 1:5 but less than 2:3.