A method and device concerning iii-nitride edge emitting laser diode of high confinement factor with lattice matched cladding layer

Patent metadata

Field	Value
Publication number	US-2018152003-A1
Application number	US-201615574739-A
Country	US
Kind code	A1
Filing date	May 19, 2016
Priority date	May 19, 2015
Publication date	May 31, 2018
Grant date	—

Abstract

Edge-emitting laser diodes having high confinement factors and lattice-matched, porous cladding layers are described. The laser diodes may be formed from layers of III-nitride material. A cladding layer may be electrochemically etched to form a porous cladding layer having a high refractive index contrast with an active junction of the device. A transparent conductive oxide layer may be deposited to form a top-side cladding layer with high refractive index contrast and low resistivity.

First claim

1 . A semiconductor laser diode comprising an active region formed on a substrate and arranged for edge emission of a laser beam and a porous cladding layer formed between the substrate and the active region.

2 . The semiconductor laser diode of claim 1 , wherein a difference in a first refractive index value for the active region and a second refractive index value for the porous cladding layer is greater than 0.1.

3 . The semiconductor laser diode of claim 1 , wherein the porous cladding layer comprises n-doped GaN.

4 . The semiconductor laser diode of claim 3 , wherein a doping density of the porous cladding layer is between 1×10 18 cm −3 and 1×10 19 cm −3 .

5 . The semiconductor laser diode of claim 4 , further comprising an n-type GaN layer having a doping level between 1×10 18 cm −3 and 5×10 18 cm −3 located between the porous cladding layer and the substrate.

6 . The semiconductor laser diode of claim 1 , wherein a porosity of the porous cladding layer is between 30% and 60%.

7 . The semiconductor laser diode of claim 6 , wherein an average pore diameter for the porous cladding layer is between 10 nm and 100 nm.

8 . The semiconductor laser diode of claim 1 , wherein a thickness of the porous cladding layer is between 200 nm and 500 nm.

9 . The semiconductor laser diode of claim 1 , wherein the active region comprises multiple-quantum wells.

10 . The semiconductor laser diode of claim 1 , further comprising a conductive oxide cladding layer formed on a side of the active region opposite the porous cladding layer.

11 . The semiconductor laser diode of claim 10 , having a one-dimensional confinement factor Γ 1D between 4% and 10%.

12 . The semiconductor laser diode of claim 10 , wherein the conductive oxide cladding layer comprises indium tin oxide.

13 . The semiconductor laser diode of claim 1 , incorporated as an optical source for a light.

14 . A method for making a semiconductor laser diode, the method comprising:
forming an n+-doped GaN layer on a substrate; forming an active junction for and edge-emitting semiconductor laser diode adjacent to the n+-doped GaN layer; etching trenches through the active junction to expose a surface of the n+-doped GaN layer; and subsequently wet etching the n+-doped GaN layer to convert the n+-doped GaN layer to a porous cladding layer.

15 . The method of claim 14 , further comprising forming a conductive oxide cladding layer adjacent to the active junction.

16 . The method of claim 14 , further comprising forming an n-type current spreading layer adjacent to the n+-doped GaN layer, wherein a doping concentration of the n-type current spreading layer is between 1×10 18 cm −3 and 5×10 18 cm −3 .

17 . The method of claim 14 , wherein forming an active junction comprises depositing n-type GaN, multiple quantum wells, and p-type GaN by epitaxy.

18 . The method of claim 14 , wherein the wet etching is performed after forming the active junction.

19 . The method of claim 14 , wherein the wet etching comprises electrochemical etching that laterally porosifies the n+-doped GaN layer and does not require photo-assisted etching.

20 . The method of claim 19 , wherein the wet etching uses nitric acid as an electrolyte to porosify the n+-doped GaN layer.

21 . The method of claim 19 , wherein the wet etching uses hydrofluoric acid as an electrolyte to porosify the n+-doped GaN layer.

22 . The method of claim 14 , wherein the n+-doped GaN layer has a doping concentration between 5×10 18 cm −3 and 2×10 20 cm −3 .

Assignees

• Univ Yale

Inventors

• Han Jung
• Li Yufeng
• Yuan Ge

Classifications

• H10P50/00

  Etching of wafers, substrates or parts of devices · CPC title

• H01S5/3213

  asymmetric clading layers · CPC title

• H01S2304/04

  MOCVD or MOVPE · CPC title

• H01S5/2009 Primary

  by using electron barrier layers · CPC title

• H01S5/34333

  with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser · CPC title