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GB2352871A - Controllable selective oxidation on VCSELs - Google Patents

Controllable selective oxidation on VCSELs Download PDF

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Publication number
GB2352871A
GB2352871A GB9917321A GB9917321A GB2352871A GB 2352871 A GB2352871 A GB 2352871A GB 9917321 A GB9917321 A GB 9917321A GB 9917321 A GB9917321 A GB 9917321A GB 2352871 A GB2352871 A GB 2352871A
Authority
GB
United Kingdom
Prior art keywords
layer
ions
regions
oxidation
implanted
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9917321A
Other versions
GB9917321D0 (en
Inventor
Klaus Streubel
Anita Risberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Microsemi Semiconductor AB
Original Assignee
Mitel Semiconductor AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitel Semiconductor AB filed Critical Mitel Semiconductor AB
Priority to GB9917321A priority Critical patent/GB2352871A/en
Publication of GB9917321D0 publication Critical patent/GB9917321D0/en
Priority to CA 2314478 priority patent/CA2314478A1/en
Priority to SE0002735A priority patent/SE0002735L/en
Priority to DE2000135913 priority patent/DE10035913A1/en
Priority to FR0009661A priority patent/FR2804794A1/en
Publication of GB2352871A publication Critical patent/GB2352871A/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
    • H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
    • H01S5/18308—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] having a special structure for lateral current or light confinement
    • H01S5/18311—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL] having a special structure for lateral current or light confinement using selective oxidation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/2054—Methods of obtaining the confinement
    • H01S5/2059—Methods of obtaining the confinement by means of particular conductivity zones, e.g. obtained by particle bombardment or diffusion
    • H01S5/2063—Methods of obtaining the confinement by means of particular conductivity zones, e.g. obtained by particle bombardment or diffusion obtained by particle bombardment

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)
  • Element Separation (AREA)

Abstract

A method for controlling the oxidation of a layer 190 extending in a transverse plane in a vertical cavity surface emitting laser (VCSEL) 10, involves selectively implanting ions into transversely spaced regions 190a of the layer to change the concentration of the oxidisable material. Subsequently the layer is oxidised and the degree of oxidation of the layer varies in a transverse direction between the implanted regions and non-implanted regions of the layer. The layer may be AlAs or AlGaAs, in which case the implanted ions may be Ga ions. Alternatively the implanted ions may be oxygen.

Description

2352871 CONTROLLABLE SELECTIVE OXIDATION ON VCSELS This invention relates
to generally to VCSELs, vertical cavity surface emitting lasers, and more particularly to 5 a method of controlling the selective oxidation of VCSELs.
In a VCSELs, an active region is arranged between stacks of layers of alternating refractive index forming Bragg mirrors in a vertical arrangement. Typically the Bragg layers are made of gallium arsenide/gallium aluminum arsenide (GaAs/AlGaAs). VCSELs are advantageous for a number of reasons, such as their planar construction, the fact that they emit light perpendicular to the surface of the die, and the possibility of array fabrication. They find application, for example, as drivers in fiber optic communications.
In a complete VCSEL, cladding regions are arranged on either side of the active region. Transition regions are located between the cladding regions and the Bragg mirrors to allow for a smooth transition from the cladding region to the Bragg stacks. Contact regions are formed on the outer side of the Bragg stacks. The transition regions are typically formed of layers of AlAs or AlGaAs to match the Bragg layers.
A typical VCSEL of this type is described in US patent number 5,764,671, the contents of which are incorporated herein by reference.
It is desirable to selectively oxidise portions of the AlAs or AlGaAs layers in the Bragg mirrors or transition regions to bring about a number of advantages, such as improved carrier confinement, decreased series resistance, and the like, which improves optical gain and lowers the threshold current of the VCSEL. This technique is disclosed in US patent number 5,359,618 the contents of which are incorporated herein by reference.
In the prior art, the oxidation process is controlled by setting the time or water vapour flow, in practice -by removing the sample from the oven or just turning off the water vapour. It is also known in the prior art that the percentage of gallium can be changed to enhance or reduce the oxidation of the bulk Al(x)GA(.)As layer.
An object of the invention is to improve the ability to selectively oxidise portions of the Bragg Layers.
According to the present invention there is provided a method for controlling the oxidation of a layer containing an oxidisable material extending in a transverse plane in a vertical cavity surface emitting laser (VCSEL), comprising the steps of selectively implanting ions into transversely spaced regions of the layer to change the concentration of the oxidisable material in the transversely spaced regions, and subsequently oxidising the layer, whereby the degree of oxidation of the layer in a transverse direction varies between the implanted regions and non-implanted regions of the layer.
For example, the implantation of Ga ions into AlAS or AlGaAs will lower the concentration of Al, which in turn has the effect of decreasing the oxidation rate significantly. By masking the layer, the oxidation rate can be selectively controlled over its transverse dimension.
other types of ion can be used to control the oxidation in a specific layer. For example, the implantation of oxygen ions can be used for the selective oxidation of a layer with a high concentration of Al. In this case, the wafer must be heated after the implantation.
This technique can be applied to all VCSEL materials where a change of the metal (normally Al) concentration in a specific layer is desired.
By fabricating more reproducible components, the 10 production yield can be made higher, giving consumers a higher quality product.
The invention also provides a vertical cavity surface emitting laser, comprising at least one oxidation layer containing an oxidised material divided into a plurality of transversely spaced regions implanted with ions, the degree of oxidation of said layer varying in a transverse direction between said implanted regions and non- implanted regions in said layer.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which the single Figure is a cross section through a VCSEL.
The VCSEL 10 is formed on a substrate 101 with a contact region on the underside. The VCSEL 10 consists of Bragg stack 109, active region 117, which may be sandwiched between cladding layers, Bragg stack 127, and contact region 132. This general structure is described in more detail in US patent number 5,764,671, the contents of which are herein incorporated by reference.
A layer 190 intended for oxidation and consisting of 35 AlGaAs is located above the active layer 117. The oxidation layer 190 is intended for oxidation to enhance the properties of the device as described above.
During the manufacture process, the layer 190 is masked to leave exposed regions 190a while regions 190b are covered by the mask. Gallium ions are then implanted using a conventional implantation process into the exposed regions 190a to reduce the Al concentration in the layer 109.
After removal of the mask from the oxidation layer 190, the device is placed in an oxidation oven in a conventional manner. The degree of oxidation varies across the wafer in the direction indicated by the arrow X.
Where the Al concentration is reduced, in the regions 190a, there is a significant decrease in the oxidation rate, as a result of which the degree of oxidation varies across the wafer.
By varying the size of the regions 190a and the implantation dose, the degree of oxidation can be selectively controlled across the wafer.

Claims (12)

  1. Claims
    I. A method for controlling the oxidation of a layer containing an oxidisable material extending in a transverse plane in a vertical cavity surface emitting laser (VCSEL), comprising the steps of selectively implanting ions into transversely spaced regions of said layer to change the concentration of the oxidisable material in said transversely spaced regions, and subsequently oxidising said layer, whereby the degree of oxidation of said layer in a transverse direction varies between the implanted regions and non-implanted regions of said layer.
  2. 2. A method as claimed in claim 1, wherein said layer is made of AlAs or AlGaAs, aluminum constituting said oxidisable material, and said ions are gallium ions.
  3. 3. A method as claimed in claim 1, wherein said layer contains Al, which forms said oxidisable material, and said ions are oxygen ions.
  4. 4. A method as claimed in claim 1, wherein said layer is heated after implantation.
  5. S. A method as claimed in any one of claims 1 to 3, wherein said ion implantation is carried out through a mask into said regions.
  6. 6. A method as claimed in any one of claims 1 to 5, wherein the implantation dose for said transversely spaced regions is varied across the layer.
  7. 7. A method as claimed in any one of claims 1 to 6, wherein the size of said transversely spaced regions - 6 varies across the layer.
  8. 8. A vertical cavity surface emitting laser, comprising at least one oxidation layer containing an oxidised material divided into a plurality of transversely spaced regions implanted with ions, the degree of oxidation of said layer varying in a transverse direction between said implanted regions and non-implanted regions in said layer.
  9. 9. A vertical cavity surface emitting laser as claimed in claim 8, wherein said layer is made of AlAs or AlGaAs, and said ions are gallium ions.
  10. 10. A vertical cavity surface emitting laser as claimed in claim 8, wherein said oxidisable material is aluminum and said implanted ions are oxygen ions.
  11. 11. A method for controlling the oxidation of a layer substantially as herein described with reference to the accompanying drawings.
  12. 12. A vertical cavity surface emitting laser substantially as herein described with reference to the accompanying drawings.
GB9917321A 1999-07-24 1999-07-24 Controllable selective oxidation on VCSELs Withdrawn GB2352871A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB9917321A GB2352871A (en) 1999-07-24 1999-07-24 Controllable selective oxidation on VCSELs
CA 2314478 CA2314478A1 (en) 1999-07-24 2000-07-20 Controllable selective oxidation on vcsels
SE0002735A SE0002735L (en) 1999-07-24 2000-07-21 Controlled selective oxidation of heat
DE2000135913 DE10035913A1 (en) 1999-07-24 2000-07-21 Controllable selective oxidation on layer in transverse plane of vertical cavity surface emitting laser involves selective ion implantation into transversely spaced regions of layer to change oxidizable material concentration in the regions
FR0009661A FR2804794A1 (en) 1999-07-24 2000-07-24 METHOD FOR SELECTIVELY CONTROLLING THE OXIDATION OF A LAYER IN A VERTICAL CAVITY SURFACE EMISSION LASER, AND LASER OBTAINED BY MEANS OF THIS METHOD

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9917321A GB2352871A (en) 1999-07-24 1999-07-24 Controllable selective oxidation on VCSELs

Publications (2)

Publication Number Publication Date
GB9917321D0 GB9917321D0 (en) 1999-09-22
GB2352871A true GB2352871A (en) 2001-02-07

Family

ID=10857817

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9917321A Withdrawn GB2352871A (en) 1999-07-24 1999-07-24 Controllable selective oxidation on VCSELs

Country Status (5)

Country Link
CA (1) CA2314478A1 (en)
DE (1) DE10035913A1 (en)
FR (1) FR2804794A1 (en)
GB (1) GB2352871A (en)
SE (1) SE0002735L (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2377318A (en) * 2001-07-03 2003-01-08 Mitel Semiconductor Ab Vertical Cavity Surface Emitting Laser

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997022991A1 (en) * 1995-12-18 1997-06-26 Picolight Incorporated Conductive element with lateral oxidation barrier
WO1997047061A1 (en) * 1996-06-07 1997-12-11 Picolight Incorporated Light emitting device having an electrical contact through a layer containing oxidized material
WO1998005073A1 (en) * 1996-07-25 1998-02-05 Picolight Incorporated Lens comprising at least one oxidized layer and method for forming same
EP0844651A1 (en) * 1996-11-26 1998-05-27 Xerox Corporation Method of controlling oxidation in multilayer semiconductor structure comprising Group III elements
JPH11112088A (en) * 1997-10-07 1999-04-23 Matsushita Electric Ind Co Ltd Surface emitting semiconductor laser and manufacture thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997022991A1 (en) * 1995-12-18 1997-06-26 Picolight Incorporated Conductive element with lateral oxidation barrier
WO1997047061A1 (en) * 1996-06-07 1997-12-11 Picolight Incorporated Light emitting device having an electrical contact through a layer containing oxidized material
WO1998005073A1 (en) * 1996-07-25 1998-02-05 Picolight Incorporated Lens comprising at least one oxidized layer and method for forming same
EP0844651A1 (en) * 1996-11-26 1998-05-27 Xerox Corporation Method of controlling oxidation in multilayer semiconductor structure comprising Group III elements
JPH11112088A (en) * 1997-10-07 1999-04-23 Matsushita Electric Ind Co Ltd Surface emitting semiconductor laser and manufacture thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2377318A (en) * 2001-07-03 2003-01-08 Mitel Semiconductor Ab Vertical Cavity Surface Emitting Laser

Also Published As

Publication number Publication date
SE0002735D0 (en) 2000-07-21
GB9917321D0 (en) 1999-09-22
SE0002735L (en) 2001-01-25
CA2314478A1 (en) 2001-01-24
DE10035913A1 (en) 2001-03-01
FR2804794A1 (en) 2001-08-10

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)