(Al,Ga,In)N diode laser fabricated at reduced temperature

• US 8,790,943 B2
• Filed: 08/23/2012
• Issued: 07/29/2014
• Est. Priority Date: 05/30/2008
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Cohen, Daniel A., DenBaars, Steven P., Nakamura, Shuji
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): TOBERGTE, NICHOLAS J
• Application Number:
  US13/593,340
• Publication Number:
  US 20130215921A1
• Time in Patent Office: 705 Days
• Field of Search: 257/98, 257/103, 257/449, 438/22, 438/31, 438/604, 438/609
• US Class Current: 438/31
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0215 Bonding to the substrate
• CPC Class Codes: H01S 5/0217 Removal of the substrate
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/2054 Methods of obtaining the confinement
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/3013 AIIIBV compounds
• CPC Class Codes: H01S 5/3211 characterised by special cladding layers, e.g. details on band-discontinuities
• CPC Class Codes: H01S 5/3213 asymmetric clading layers
• CPC Class Codes: H01S 5/3214 comprising materials from other groups of the Periodic Table than the materials of the active layer, e.g. ZnSe claddings and GaAs active layer
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A method of fabricating an (Al,Ga,In)N laser diode, comprising depositing one or more III-N layers upon a growth substrate at a first temperature, depositing an indium containing laser core at a second temperature upon layers deposited at a first temperature, and performing all subsequent fabrication steps under conditions that inhibit degradation of the laser core, wherein the conditions are a substantially lower temperature than the second temperature.

Claims

1. A method of fabricating an (Al,Ga,In)N laser diode, comprising

fabricating an indium containing laser core;

and

fabricating subsequent layers on or above the laser core that function at least as a waveguide or cladding layer;

wherein the subsequent layers fabricated on or above the laser core comprise a crystalline, polycrystalline or amorphous transparent conducting oxide grown or deposited on or above the laser core; and

wherein the indium containing laser core is fabricated at a first temperature, and the subsequent lavers are grown or deposited on or above the laser core at or below a second temperature that is lower than the first temperature, to inhibit degradation of the laser core.

2. The method of claim 1, wherein the subsequent layers comprise one or more of:

at least one waveguide core layer, at least one waveguide cladding layer, at least one carrier injection layer, at least one carrier blocking layer, and at least one electrical contact layer.

3. The method of claim 1, wherein the subsequent layers fabricated on or above the laser core comprise a crystalline transparent conducting oxide grown or deposited on or above the laser core, and the crystalline transparent conductive oxide layer is grown from an aqueous solution.

4. The method of claim 3, wherein the crystalline transparent conducting oxide is combined with an amorphous or polycrystalline transparent conducting oxide layer deposited by physical vapor deposition.

5. The method of claim 1, wherein the subsequent layers fabricated on the laser core comprise at least one transparent and electrically conducting layer formed on or above an indium-containing active region as the waveguide or cladding layer and to provide electrical contact to the indium-containing active region.

6. The method of claim 1, wherein the laser core generates green light having a laser wavelength longer than 515 nm.

7. An (Al,Ga,In)N laser diode fabricated using the method of claim 1.

8. A method of fabricating an (Al,Ga,In)N laser diode, comprising

fabricating an indium containing laser core;

and

fabricating subsequent layers on or above the laser core that function at least as a waveguide or cladding layer;

wherein the subsequent layers fabricated on or above the laser core comprise a crystalline transparent conducting oxide grown separately from the laser core and then bonded to the laser core; and

wherein the indium containing laser core is fabricated at a first temperature, and the subsequent layers are grown separately from the laser core and then bonded to the laser core at or below a second temperature that is lower than the first temperature, to inhibit degradation of the laser core.

9. The method of claim 8, wherein the subsequent layers comprise one or more of:

at least one waveguide core layer, at least one waveguide cladding layer, at least one carrier injection layer, at least one carrier blocking layer, and at least one electrical contact layer.

10. The method of claim 8, wherein the subsequent layers fabricated on the laser core comprise at least one transparent and electrically conducting layer formed on or above an indium-containing active region as the waveguide or cladding layer and to provide electrical contact to the indium-containing active region.

11. The method of claim 10, wherein the transparent and electrically conducting layer comprises one or more oxide layers or bonded (Al,Ga,In)N layers, and the transparent and electrically conducting layer is deposited by a method other than crystal growth at a temperature greater than 550°

C.

12. The method of claim 8, wherein the laser core generates green light having a laser wavelength longer than 515 nm.

13. An (Al,Ga,In)N laser diode fabricated using the method of claim 8.

14. A method of fabricating an (Al,Ga,In)N laser diode, comprising

fabricating an indium containing laser core;

and

fabricating subsequent layers on or above the laser core that function at least as a waveguide or cladding layer;

wherein the subsequent layers fabricated on or above the laser core comprise crystalline (Al,Ga,In)N layers grown on a separate substrate and then bonded to the laser core; and

wherein the indium containing laser core is fabricated at a first temperature, and the subsequent layers are grown on the separate substrate and then bonded to the laser core at or below a second temperature that is lower than the first temperature, to inhibit degradation of the laser core.

15. The method of claim 14, wherein the subsequent layers comprise one or more of:

at least one waveguide core layer, at least one waveguide cladding layer, at least one carrier injection layer, at least one carrier blocking layer, and at least one electrical contact layer.

16. The method of claim 14, wherein the subsequent layers fabricated on the laser core comprise at least one transparent and electrically conducting layer formed on or above an indium-containing active region as the waveguide or cladding layer and to provide electrical contact to the indium-containing active region.

17. The method of claim 16, wherein the transparent and electrically conducting layer comprises one or more oxide layers or bonded (Al,Ga,In)N layers, and the transparent and electrically conducting layer is deposited by a method other than crystal growth at a temperature greater than 550°

C.

18. The method of claim 14, wherein the laser core generates green light having a laser wavelength longer than 515 nm.

19. An (Al,Ga,In)N laser diode fabricated using the method of claim 14.