Use of GaAs extended barrier layers between active regions containing nitrogen and AlGaAs confining layers

• US 7,167,495 B2
• Filed: 10/01/2004
• Issued: 01/23/2007
• Est. Priority Date: 12/21/1998
• Status: Expired due to Fees

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Johnson, Ralph H.
• Primary Examiner(s): Harvey; Minsun Oh
• Assistant Examiner(s): Nguyen; Dung (Michael) T.
• Application Number:
  US10/956,985
• Publication Number:
  US 20050123015A1
• Time in Patent Office: 844 Days
• Field of Search: 372/43.01, 372/45.01
• US Class Current: 372/43.01
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01S 2302/00 Amplification / lasing wavelength
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/3201 incorporating bulkstrain effects, e.g. strain compensation, strain related to polarisation
• CPC Class Codes: H01S 5/32358 containing very small amounts, usually less than 1%, of an additional III or V compound to decrease the bandgap strongly in a non-linear way by the bowing effect
• CPC Class Codes: H01S 5/32366 (In)GaAs with small amount of N
• CPC Class Codes: H01S 5/34 comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers H01S5/36 takes precedence
• CPC Class Codes: H01S 5/3403 having a strained layer structure in which the strain performs a special function, e.g. general strain effects, strain versus polarisation
• CPC Class Codes: H01S 5/3406 including strain compensation
• CPC Class Codes: H01S 5/34306 emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers
• CPC Class Codes: H01S 5/34313 with a well layer having only As as V-compound, e.g. AlGaAs, InGaAs
• CPC Class Codes: H01S 5/34346 characterised by the materials of the barrier layers
• CPC Class Codes: H01S 5/34353 based on (AI)GaAs

Abstract

Incorporation of a GaAs “Extended lower barrier” in between quantum wells using nitrogen and confining layers using aluminum. Not to be confused with barrier layers used in quantum wells, the extended lower barrier is formed between the active region a nd the outer/confining layers where N and Al are respectively used. N and Al can be separated in the case where, for example, AlGaAs is being used in the confining layers and any nitrogen containing material is being used in the active region. Aluminum and Nitrogen when allowed to combine can cause deep traps and resultant non-radiative recombination, therefore N and Al pairing should be prevented. The GaAs extended barrier layer can provide a protective measure against such combination.

Claims

1. A vertical cavity surface emitting laser (VCSEL) comprising:

an active region including nitrogen containing layers and having a first and a second outer edge, said active region further comprising at least one quantum well and at least two barrier layers disposed on each side of said at least one quantum well;

first and second extended barrier layers comprised of GaAs, wherein said first extended barrier layer is disposed next to and outside of said first outer edge of said active region and said second extended barrier layer is disposed next to and outside of said second outer edge of said active region; and

first and second confinement regions, at least one of the first and second confinement regions comprising aluminum, wherein said first confinement regions is disposed next to said first extended barrier layer and opposite said active region and said second confinement region is disposed next to said second extended barrier layer opposite said active region.

2. A VCSEL as defined in claim 1, wherein spacing between said nitrogen containing layers and said aluminum containing layers is between 5 nm and 100 nm.

3. A VCSEL as defined in claim 1, wherein spacing between said nitrogen containing layers and aluminum containing layer is less than 100 nm.

4. A VCSEL as defined in claim 1, wherein said at least two barrier layers further comprise at least two integrated layers further comprising a first GaAs layer and a second GaAsN layer, wherein said at least two barrier layers are disposed on each side of said at least one quantum well.

5. A VCSEL as defined in claim 4, wherein said at least two integrated layers further comprise a GaAs layer sandwiched between two GaAsN layers.

6. A VCSEL as defined in claim 1, wherein said confinement layers are comprised of AlGaAs.

7. A VCSEL as defined in claim of claim 2, wherein said at least two barrier layers contain N and said confinement regions include AlGaAs.

8. A VCSEL as defined in claim of claim 3, wherein said at least two barrier layers contain N and said confinement regions include AlGaAs.

9. A VCSEL as defined in claim 1, wherein said at least one quantum well is comprised of GaAs and at least one of:

In, Sb, P and N.

10. A VCSEL as defined in claim 4, wherein said at least one quantum well is comprised of GaAs and at least one of:

In, Sb, P and N.

11. A VCSEL as defined in claim 5, wherein said at least one quantum well is comprised of GaAs and at least one of:

In, Sb, P and N.

12. A VCSEL as defined in claim 6, wherein said at least one quantum well is comprised of GaAs and at least one of:

In, Sb, P and N.

13. A VCSEL as defined in claim 7, wherein said at least one quantum well is comprised of GaAs and at least one of:

In, Sb, P and N.

14. A VCSEL as defined in claim 1, wherein said at least one quantum well further comprises layers of a semiconductor alloy under mechanical stress interspersed with thin layers of a substrate type material, wherein said thin layers of a substrate type material serve as mechanical stabilizers for the semiconductor alloy layers to prevent the semiconductor alloy layers from relaxing.

15. A vertical cavity surface emitting laser (VCSEL), comprising:

an active region comprising;

at least one quantum well containing nitrogen and having layers of a semiconductor alloy under mechanical stress interspersed with thin layers of a substrate type material, wherein said layers of a substrate type material serve as mechanical stabilizers for the semiconductor alloy layers to prevent the semiconductor alloy layers from relaxing; and

barrier layers disposed on each side of said at least quantum well, said barrier layers including nitrogen and sandwiching said at least one quantum well;

extended barrier layers comprised of GaAs and sandwiching said active region; and

confinement layers containing Al and sandwiching said extended barrier layers.

16. A VCSEL as defined in claim 15, wherein said barrier layers are comprised of GaAsN.

17. A VCSEL as defined in claim 15, wherein said confinement layers are comprised of AlGaAs.

18. A VCSEL as defined in claim 15, wherein said barrier layers further comprise at least two integrated layers further comprising a first GaAs layer and a second GaAsN layer.

19. A VCSEL as defined in claim 18, wherein said at least two integrated layers further comprise a GaAs layer sandwiched between two GaAsN layers.

20. A VCSEL as defined in claim 15, wherein said confinement layers are comprised of AlGaAs.

21. A VCSEL as defined in claim of claim 15, wherein said barrier layers contain N and said confinement regions include AlGaAs.

22. A VCSEL as defined in claim of claim 20, wherein said barrier layers include contain N and said confinement regions include AlGaAs.

23. A VCSEL as defined in claim 15, wherein said at least one quantum well is comprised of GaAs and at least one of:

In, Sb, P and N.

24. A vertical cavity surface emitting laser (VCSEL) comprising:

an active region including nitrogen containing layers and having a first and a second outer edge, said active region further comprising;

at least one quantum well comprising layers of a semiconductor alloy under mechanical stress interspersed with thin layers of a substrate type material, wherein said thin layers of a substrate type material serve as mechanical stabilizers for the semiconductor alloy layers to prevent the semiconductor alloy layers from relaxing, wherein said semiconductor alloy comprises GaAs and at least one of;

In, Sb, P and N; and

at least two barrier layers including nitrogen and disposed on each side of said at least one quantum well;

first and second extended barrier layers comprised of GaAs, wherein said first extended barrier layer is disposed next to and outside of said first outer edge of said active region and said second extended barrier layer is disposed next to and outside of said second outer edge of said active region; and

first and second confinement regions, at least one of the first and second confinement regions comprising aluminum, wherein said first confinement regions is disposed next to said first extended barrier layer and opposite said active region and said second confinement region is disposed next to said second extended barrier layer opposite said active region.