CN110932092A - Long wavelength vertical cavity surface emitting laser and preparation method thereof - Google Patents

Long wavelength vertical cavity surface emitting laser and preparation method thereof Download PDF

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Publication number
CN110932092A
CN110932092A CN201911275025.1A CN201911275025A CN110932092A CN 110932092 A CN110932092 A CN 110932092A CN 201911275025 A CN201911275025 A CN 201911275025A CN 110932092 A CN110932092 A CN 110932092A
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layer
type
heavily doped
doped layer
type heavily
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张星
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Changchun Zhongke Changguang Space Time Photoelectric Technology Co ltd
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Changchun Zhongke Changguang Space Time Photoelectric Technology Co ltd
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    • 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
    • H01S5/185—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only horizontal cavities, e.g. horizontal cavity surface-emitting lasers [HCSEL]
    • H01S5/187—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only horizontal cavities, e.g. horizontal cavity surface-emitting lasers [HCSEL] using Bragg reflection
    • 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
    • H01S5/12—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 the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
    • H01S5/125—Distributed Bragg reflector [DBR] lasers

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

Abstract

The invention discloses a long-wavelength vertical cavity surface emitting laser.A ring intrinsic layer is arranged on the surface of an active layer, which is back to an n-type substrate, and a p-type heavily doped layer and an n-type heavily doped layer positioned on the surface of the p-type heavily doped layer, which is back to the n-type substrate, are arranged on the inner side of the ring intrinsic layer to form a buried tunnel junction structure. A tunneling conducting region is formed by the p-type heavily doped layer and the n-type heavily doped layer, current only passes through the tunneling conducting region from the center of the annular intrinsic layer due to the extremely low conductivity of the annular intrinsic layer, and effective current limitation can be formed by controlling the pattern at the center of the annular intrinsic layer; meanwhile, the light limitation in the coverage area of the annular intrinsic layer can be realized by controlling the thickness of the annular intrinsic layer, so that the current and the light in the long-wavelength vertical cavity surface emitting laser are more concentrated, and the performance of the long-wavelength vertical cavity surface emitting laser is improved. The invention also provides a preparation method, and the preparation method also has the beneficial effects.

Description

Long wavelength vertical cavity surface emitting laser and preparation method thereof
Technical Field
The invention relates to the technical field of lasers, in particular to a long-wavelength vertical cavity surface emitting laser and a preparation method of the long-wavelength vertical cavity surface emitting laser.
Background
Long wavelength Vertical Cavity Surface Emitting Lasers (VCSELs) can emit 1.3-1.8um band laser light from the surface, and have advantages of low threshold, low power consumption, easy integration, etc. compared with edge emitting lasers. The long-wavelength vertical cavity surface emitting laser can be applied to the fields of long-distance (>80km) high-speed optical communication, optical interconnection, gas detection, laser radar and the like, and has great application prospect in the future along with the continuous development of informatization, intellectualization and greening society.
The traditional long wavelength Vertical Cavity Surface Emitting Laser (VCSEL) preparation technology can only be based on an indium phosphide (InP) material system, and is difficult to form effective photoelectric limitation due to the problems of large resistance, serious heat generation, serious inter-band absorption in valence band (IvBA) and the like of a P-type InP layer. Therefore, finding a new optical confinement structure to improve the performance of the long wavelength vcsel is an urgent problem to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide a long-wavelength vertical cavity surface emitting laser, which can improve the performance of the long-wavelength vertical cavity surface emitting laser; another object of the present invention is to provide a method for manufacturing a long wavelength vcsel, which can improve the performance of the long wavelength vcsel.
To solve the above technical problem, the present invention provides a long wavelength vertical cavity surface emitting laser, including:
an n-type substrate;
an n-type DBR mirror located on the n-type substrate surface;
an active layer on a surface of the n-type DBR mirror facing away from the n-type substrate;
the annular intrinsic layer is positioned on the surface, facing away from the n-type substrate, of the active layer;
the p-type heavily doped layer is at least positioned on the inner side of the annular intrinsic layer, and the n-type heavily doped layer is at least positioned on the inner side of the annular intrinsic layer; the p-type heavily doped layer at least covers the surface of the active layer at the inner side of the annular intrinsic layer, and the n-type heavily doped layer is positioned at the surface of the p-type heavily doped layer, which faces away from the n-type substrate;
the n-type conducting layer is positioned on one side, back to the n-type substrate, of the annular intrinsic layer; the n-type conducting layer covers the n-type heavily doped layer;
the p-type DBR reflector is positioned on one side surface, opposite to the n-type substrate, of the n-type conducting layer; the p-type DBR reflector corresponds to the inner side region of the annular intrinsic layer;
a p-side electrode electrically connected to the n-type conductive layer, and an n-side electrode electrically connected to the n-type substrate.
Optionally, the inner side of the annular intrinsic layer is cylindrical; the p-type DBR reflector is cylindrical.
Optionally, the dopant of the p-type heavily doped layer is carbon, and the doping concentration of the p-type heavily doped layer ranges from 5 × 1019cm-3To 1X 1020cm-3Inclusive of the endpoint values; the doping agent of the n-type heavily doped layer is zinc, and the value range of the doping concentration of the n-type heavily doped layer is 1 multiplied by 1019cm-3To 3X 1019cm-3Inclusive.
Optionally, the value range of the thickness of the p-type heavily doped layer is 8nm to 15nm, including an endpoint value; the thickness of the n-type heavily doped layer ranges from 15nm to 30nm, inclusive.
Optionally, the p-surface electrode is located on a surface of the n-type conductive layer facing away from the n-type substrate, and the n-surface electrode is located on a surface of the n-type substrate facing away from the n-type DBR mirror.
Optionally, the thickness of the annular intrinsic layer is equal to a quarter of the lasing wavelength of the laser divided by the refractive index of the annular intrinsic layer; the p-type heavily doped layer and the n-type heavily doped layer are both only positioned on the inner side of the annular intrinsic layer.
Optionally, the thickness of the annular intrinsic layer is equal to one half of the wavelength of the standing wave of the laser; the p-type heavily doped layer also covers one side surface of the annular intrinsic layer, which faces away from the n-type substrate.
The invention also provides a preparation method of the long-wavelength vertical cavity surface emitting laser, which comprises the following steps:
epitaxially growing an n-type DBR mirror on the surface of the n-type substrate;
epitaxially growing an active layer on the surface of one side, back to the n-type substrate, of the n-type DBR reflector;
arranging an annular intrinsic layer, a p-type heavily doped layer and an n-type heavily doped layer on one side of the active layer, which faces away from the n-type substrate; the annular intrinsic layer is positioned on the surface, facing away from the n-type substrate, of the active layer; the p-type heavily doped layer and the n-type heavily doped layer are at least positioned on the inner side of the annular intrinsic layer, the p-type heavily doped layer at least covers the surface of the active layer positioned on the inner side of the annular intrinsic layer, and the n-type heavily doped layer is positioned on one surface of the p-type heavily doped layer, which faces away from the n-type substrate;
epitaxially growing an n-type conducting layer on one side, back to the n-type substrate, of the annular intrinsic layer; the n-type conducting layer covers the n-type heavily doped layer;
epitaxially growing a p-type DBR reflector on the surface of one side, opposite to the n-type substrate, of the n-type conducting layer; the p-type DBR reflector corresponds to the inner side region of the annular intrinsic layer;
and arranging a p-surface electrode electrically connected with the n-type conducting layer and an n-surface electrode electrically connected with the n-type substrate to manufacture the long-wavelength vertical cavity surface emitting laser.
Optionally, the disposing of the annular intrinsic layer, the p-type heavily doped layer, and the n-type heavily doped layer on the side of the active layer opposite to the n-type substrate includes:
sequentially and selectively growing a p-type heavily doped layer and an n-type heavily doped layer in an area on one side surface of the active layer, which is opposite to the n-type substrate; the n-type heavily doped layer is only positioned on one side surface of the p-type heavily doped layer, which faces away from the n-type substrate;
and epitaxially growing an annular intrinsic layer surrounding the p-type heavily doped layer and the n-type heavily doped layer on a selected area of the surface of one side of the active layer, which is back to the n-type substrate.
Optionally, the disposing of the annular intrinsic layer, the p-type heavily doped layer, and the n-type heavily doped layer on the side of the active layer opposite to the n-type substrate includes:
epitaxially growing an intrinsic layer on the surface of one side, back to the n-type substrate, of the active layer;
etching a preset region on the surface of the intrinsic layer to form an annular intrinsic layer, and exposing a preset region on one side surface of the active layer, which faces away from the n-type substrate;
sequentially epitaxially growing a p-type heavily doped layer and an n-type heavily doped layer on the surface of the annular intrinsic layer; the p-type heavily doped layer covers the surface of the active layer at the inner side area of the annular intrinsic layer and covers the surface of the intrinsic layer, which faces away from the n-type substrate.
The invention provides a long-wavelength vertical cavity surface emitting laser, wherein an annular intrinsic layer is arranged on the surface, back to an n-type substrate, of an active layer, a p-type heavily doped layer and an n-type heavily doped layer located on the surface, back to the n-type substrate, of the p-type heavily doped layer are arranged on the inner side of the annular intrinsic layer to form a buried tunnel junction structure (BTJ). A tunneling conducting region is formed by the p-type heavily doped layer and the n-type heavily doped layer, current only passes through the tunneling conducting region from the center of the annular intrinsic layer due to the extremely low conductivity of the annular intrinsic layer, and effective current limitation can be formed by controlling the pattern at the center of the annular intrinsic layer; meanwhile, the light limitation in the coverage area of the annular intrinsic layer can be realized by controlling the thickness of the annular intrinsic layer, so that the current and the light in the long-wavelength vertical cavity surface emitting laser are more concentrated, and the performance of the long-wavelength vertical cavity surface emitting laser is improved.
The invention also provides a preparation method of the long-wavelength vertical cavity surface emitting laser, and the prepared long-wavelength vertical cavity surface emitting laser also has the beneficial effects, and the details are not repeated herein.
Drawings
In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a long wavelength vertical cavity surface emitting laser according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a specific long wavelength VCSEL according to an embodiment of the invention;
FIG. 3 is a schematic diagram of another exemplary long wavelength VCSEL structure provided in an embodiment of the invention;
FIG. 4 is a graph of the standing wave distribution in the long wavelength VCSEL of FIG. 3;
FIG. 5 is a flowchart of a method for fabricating a long wavelength VCSEL according to an embodiment of the present invention;
FIG. 6 is a flowchart illustrating a method for fabricating a long wavelength VCSEL according to an embodiment of the present invention;
FIG. 7 is a flowchart of another specific method for fabricating a long wavelength VCSEL in accordance with embodiments of the present invention.
In the figure: the semiconductor device comprises an n-type substrate, an n-type DBR mirror, an active layer, an annular intrinsic layer, a p-type heavily doped layer, a n-type heavily doped layer, a p-type conductive layer, a p-type DBR mirror, an n-type electrode, a p-type electrode and a photoelectric limiting layer, wherein the n-type DBR mirror is 2, the n-type DBR mirror is 3, the annular intrinsic layer is 4, the p-type heavily doped layer is 5, the n.
Detailed Description
The core of the invention is to provide a long wavelength vertical cavity surface emitting laser. In the prior art, a long wavelength Vertical Cavity Surface Emitting Laser (VCSEL) preparation technology can only be based on an indium phosphide (InP) material system, and is difficult to form effective photoelectric limitation due to the problems of large resistance, severe heat generation of a P-type InP layer, severe inter-band absorption in valence band (IvBA), and the like.
In the long wavelength vertical cavity surface emitting laser provided by the invention, the annular intrinsic layer is arranged on the surface of the active layer, which is back to the n-type substrate, the p-type heavily doped layer and the n-type heavily doped layer positioned on the surface of the p-type heavily doped layer, which is back to the n-type substrate, are arranged on the inner side of the annular intrinsic layer to form a buried tunnel junction structure (BTJ). A tunneling conducting region is formed by the p-type heavily doped layer and the n-type heavily doped layer, current only passes through the tunneling conducting region from the center of the annular intrinsic layer due to the extremely low conductivity of the annular intrinsic layer, and effective current limitation can be formed by controlling the pattern at the center of the annular intrinsic layer; meanwhile, the light limitation in the coverage area of the annular intrinsic layer can be realized by controlling the thickness of the annular intrinsic layer, so that the current and the light in the long-wavelength vertical cavity surface emitting laser are more concentrated, and the performance of the long-wavelength vertical cavity surface emitting laser is improved.
In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a long wavelength vertical cavity surface emitting laser according to an embodiment of the present invention.
Referring to fig. 1, in the embodiment of the present invention, a long wavelength vertical cavity surface emitting laser includes an n-type substrate 1; an n-type DBR mirror 2 located on the surface of the n-type substrate 1; an active layer 3 positioned on the surface of one side of the n-type DBR mirror 2, which faces away from the n-type substrate 1; the annular intrinsic layer 4 is positioned on the surface of one side, opposite to the n-type substrate 1, of the active layer 3; a p-type heavily doped layer 5 at least inside the annular intrinsic layer 4 and an n-type heavily doped layer 6 at least inside the annular intrinsic layer 4; the p-type heavily doped layer 5 at least covers the surface of the region of the active layer 3, which is positioned at the inner side of the annular intrinsic layer 4, and the n-type heavily doped layer 6 is positioned on the surface of the p-type heavily doped layer 5, which is back to the n-type substrate 1; an n-type conducting layer 7 positioned on one side of the annular intrinsic layer 4, which faces away from the n-type substrate 1; the n-type conducting layer 7 covers the n-type heavily doped layer 6; a p-type DBR mirror 8 positioned on the surface of one side, opposite to the n-type substrate 1, of the n-type conducting layer 7; the p-type DBR mirror 8 corresponds to the inner region of the annular intrinsic layer 4; a p-side electrode 10 electrically connected to the n-type conductive layer 7, and an n-side electrode 9 electrically connected to the n-type substrate 1.
The n-type substrate 1 is generally used to carry the main functional structures in the laser provided by the present invention, and the following structures such as the n-type DBR mirror 2 and the active layer 3 need to be sequentially arranged on the surface of the n-type substrate 1 along the normal direction of the substrate. The specific material of the substrate is described in the present specificationThe embodiments of the present invention are not particularly limited, as the case may be. In general, an n-type InP substrate is used as a substrate of the long wavelength vertical cavity surface emitting laser in the embodiment of the present invention. The thickness of the n-type InP substrate is typically between 100 μm and 150 μm, inclusive. The n-type substrate 1 is doped with a dopant, typically zinc (Zn), at a doping concentration typically of 2X 1018cm-3。
The n-type DBR mirror 2 is specifically located on the surface of the n-type substrate 1, the n-type DBR mirror 2 is usually formed by stacking a plurality of layers with different reflectivity in a periodic arrangement, and each layer of the n-type DBR mirror 2 is usually an n-type doped layer. For the specific structure of the n-type DBR mirror 2, reference may be made to the prior art, and details thereof will not be described herein. In the embodiment of the present invention, the n-type DBR mirror 2 has a predetermined reflective light wavelength, i.e., the n-type DBR mirror 2 has a very high reflectivity for light with a predetermined wavelength, i.e., the wavelength of laser light generated by the laser. The n-type DBR mirror 2 described above typically comprises a 30 period inalgas/InP structure In embodiments of the present invention where the In component is typically 0.53 and the Ga component is typically 0.47, the thickness of each layer In the n-type DBR mirror 2 needs to be one quarter of the lasing wavelength of the laser divided by the refractive index of the layer material, and the total thickness of the n-type DBR mirror 2 typically ranges between 7 μm and 10 μm, inclusive. Since it is particularly necessary to implement long wavelength laser of 1.3 μm to 1.8 μm in the embodiments of the present invention, the thickness of the n-type BDR mirror is also changed with the change of the laser wavelength to achieve the best effect.
The active layer 3 is located on the surface of the n-type DBR mirror 2 facing away from the n-type substrate 1, and the active layer 3 is used for emitting light with a predetermined wavelength. The carrier is coupled in the active layer 3, thereby generating light of a predetermined wavelength. Specifically, the active layer 3 generally includes an n-type InP electron confinement layer on the surface of the n-type DBR mirror 2 facing away from the n-type substrate 1, an InGaAsP quantum well on the surface of the n-type InP electron confinement layer facing away from the n-type substrate 1, an InP barrier layer on the surface of the InGaAsP quantum well facing away from the n-type substrate 1, and a p-type InP electron confinement layer on the surface of the InP barrier layer facing away from the n-type substrate 1 in the embodiment of the present invention.
The InGaAsP quantum wells described above are typically intrinsic and typically have a thickness between 5nm and 15nm, inclusive. The InP barrier layers described above are also typically intrinsic, typically between 5nm and 50nm thick, inclusive. The thickness of the n-type InP electron confinement layer is usually between 100nm and 500nm, inclusive, and the dopant of the n-type InP electron confinement layer is usually Zn, and the doping concentration is usually 1 × 1016cm-3To 1X 1017cm-3(ii) a The thickness of the p-type InP electronic limiting layer is generally between 100nm and 500nm, the doping concentration of the p-type InP electronic limiting layer is generally 1 × 1016cm-3To 5X 1016cm-3. It should be noted that, in the embodiment of the present invention, it is generally necessary to adjust the thickness of the n-type InP electronic confinement layer and the thickness of the p-type InP electronic confinement layer so that the total thickness of the active layer 3 is one-half of the lasing wavelength of the laser divided by the effective refractive index of the active layer 3, so as to ensure the transmission of light transmitted by the active layer 3.
The annular intrinsic layer 4 is located on the surface of the active layer 3 opposite to the n-type substrate 1, the annular intrinsic layer 4 has a certain thickness, and the annular intrinsic layer 4 needs to have a through hole which is located inside the annular intrinsic layer 4, so that the annular intrinsic layer 4 only covers a part of the surface of the active layer 3 and exposes a part of the surface of the active layer 3 corresponding to the through hole. The detailed structure of the annular intrinsic layer 4 will be described in detail in the following embodiments of the invention, and will not be described herein. In the embodiment of the present invention, the annular intrinsic layer 4 is usually made of intrinsic InP having a very small conductivity, and the annular intrinsic layer 4 may be considered as an insulating layer.
The inner side of the annular intrinsic layer 4 is provided with a p-type heavily doped layer 5 and an n-type heavily doped layer 6, wherein the p-type heavily doped layer 5 covers the surface of the active layer 3 in the inner region of the annular intrinsic layer 4, and the n-type heavily doped layer 6 is specifically positioned on the surface of the p-type heavily doped layer 5 facing away from the n-type substrate 1. The n-type heavily doped layer 6 and the p-type heavily doped layer 5 may constitute a buried tunnel junction structure (BTJ) to limit a transmission path of current. Specifically, the dopant of the p-type heavily doped layer 5 is usually the same as that of the above-mentioned p-type heavily doped layerThe doping concentration of the p-type heavily doped layer 5 is typically in the range of 5 × 10 for carbon (C)19cm-3To 1X 1020cm-3Inclusive of the endpoint values; the dopant of the n-type heavily doped layer 6 is usually zinc (Zn), and the doping concentration of the n-type heavily doped layer 6 is in the range of 1 × 1019cm-3To 3X 1019cm-3Inclusive. Specifically, the thickness of the p-type heavily doped layer 5 ranges from 8nm to 15nm, inclusive; the thickness of the n-type heavily doped layer 6 ranges from 15nm to 30nm, inclusive.
The shape of the p-type heavily doped layer 5 and the shape of the n-type heavily doped layer 6 provided inside the ring-shaped intrinsic layer 4 need to correspond to the shape of the via inside the ring-shaped intrinsic layer 4. The inner side of the annular intrinsic layer 4 is generally cylindrical in the present embodiment, and the corresponding shape of the above-mentioned p-type heavily doped layer 5 is generally circular, while the shape of the n-type heavily doped layer 6 is also generally circular. In embodiments of the present invention, the inside diameter of the annular intrinsic layer 4 is typically between 2 μm and 100 μm, inclusive; the diameter of the respective above-mentioned p-type heavily doped layer 5 is typically between 2 μm and 100 μm, inclusive; while the diameter of the n-type heavily doped layer 6 is typically also between 2 μm and 100 μm, inclusive.
The n-type conductive layer 7 is located on the side of the ring-shaped intrinsic layer 4 facing away from the n-type substrate 1, and the n-type conductive layer 7 is usually required to shield the ring-shaped intrinsic layer 4, the p-type heavily doped layer 5, and the n-type heavily doped layer 6 from the side of the ring-shaped intrinsic layer 4 facing away from the n-type substrate 1. Normally, the n-type conductive layer 7 contacts the n-type heavily doped layer 6, and the n-type conductive layer 7 covers the n-type heavily doped layer 6. Specifically, the n-type conductive layer 7 is typically an n-type InP conductive layer, which is typically 500nm to 3 μm thick, inclusive; the dopant of the n-type InP conductive layer is usually Zn, and the doping concentration is usually 1 × 1016cm-3To 3X 1018cm-3Inclusive.
The p-type DBR mirror 8 is located on the surface of the n-type conductive layer 7 facing away from the n-type substrate 1, the p-type DBR mirror 8 is usually formed by stacking a plurality of layers with different reflectivity in a periodic arrangement, and each layer of the p-type DBR mirror 8 is usually a p-type doped layer. For the specific structure of the p-type DBR mirror 8, reference may be made to the prior art, and details thereof will not be described herein. In the embodiment of the present invention, the p-type DBR mirror 8 has a predetermined reflected light wavelength, i.e., the p-type DBR mirror 8 has a very high reflectivity for light with a predetermined wavelength, i.e., the wavelength of laser light generated by the laser. Accordingly, the wavelength of the reflected light from the p-type DBR mirror 8 needs to be the same as the wavelength of the reflected light from the n-type DBR mirror 2 to ensure that the light can oscillate between the n-type DBR mirror 2 and the p-type DBR mirror 8 to generate laser light.
Specifically, the p-type DBR mirror 8 in embodiments of the invention typically comprises 4 periods of SiO2/TiO2The total thickness of the p-type DBR mirror 8, in which the thickness of each layer is one quarter of the lasing wavelength of the laser divided by the refractive index of the layer material, typically ranges between 1.5 μm and 3 μm, inclusive. Since the embodiment of the present invention provides a long wavelength laser emitting laser light with a wavelength of 1.3 to 1.8 microns, the thickness of the P-type DBR mirror 8 should be adjusted to an optimal thickness according to the wavelength of the laser light.
It should be noted that in the embodiment of the present invention, the p-type DBR mirror 8 needs to correspond to the inner region of the annular intrinsic layer 4. I.e. from the side of the n-conducting layer 7 facing away from the n-substrate 1, the p-DBR mirror 8 needs to shield the inner region of the annular intrinsic layer 4, which p-DBR mirror 8 needs to be aligned with the n-heavily doped layer 6 and the p-heavily doped layer 5. In general, the shape of the p-type DBR mirror 8 needs to correspond to the shape of the region inside the intrinsic layer. Specifically, in the present embodiment, the inner side of the annular intrinsic layer 4 is generally cylindrical, and the p-type DBR mirror 8 is also generally cylindrical.
The ring-shaped intrinsic layer 4, the p-type heavily doped layer 5, the n-type heavily doped layer 6, the n-type conductive layer 7, and the p-type DBR mirror 8 collectively constitute an optical confinement layer 11. Specifically, the light limiting layer can have different functions according to the position relationship between the annular intrinsic layer 4 and the p-type heavily doped layer 5 and the n-type heavily doped layer 6, and the specific structure of the annular intrinsic layer 4. The detailed structure of the photoelectric confinement layer 11 will be described in the following embodiments of the invention, and will not be described herein.
The p-side electrode 10 needs to be electrically connected to the n-type conductive layer 7, and the n-side electrode 9 needs to be electrically connected to the n-type substrate 1. During use, an external power source typically supplies power to the active layer 3 through the n-side electrode 9 and the p-side electrode 10 to generate laser light. Specifically, in the embodiment of the present invention, the p-surface electrode 10 is located on the surface of the n-type conductive layer 7 facing away from the n-type substrate 1, and the n-surface electrode 9 is located on the surface of the n-type substrate 1 facing away from the n-type DBR mirror 2. A laser of a vertical structure can be constructed by providing p-side electrode 10 on the surface of n-type conductive layer 7 facing away from n-type substrate 1 and n-side electrode 9 on the surface of n-type substrate 1 facing away from n-type DBR mirror 2. When the p-surface electrode 10 and the n-surface electrode 9 are arranged, the functional structure in the laser can be prevented from being etched, so that the functional structure in the laser is prevented from being damaged, and the performance of the long-wavelength vertical cavity surface emitting laser is ensured.
In the long wavelength vertical cavity surface emitting laser provided by the embodiment of the invention, the annular intrinsic layer 4 is arranged on the surface of the active layer 3, which is opposite to the n-type substrate 1, the p-type heavily doped layer 5 and the n-type heavily doped layer 6, which is positioned on the surface of the p-type heavily doped layer 5, which is opposite to the n-type substrate 1, are arranged inside the annular intrinsic layer 4 to form a buried tunnel junction structure (BTJ). A tunneling conducting region is formed by the p-type heavily doped layer 5 and the n-type heavily doped layer 6, current only passes through the tunneling conducting region from the center of the annular intrinsic layer 4 due to the extremely low conductivity of the annular intrinsic layer 4, and effective current limitation can be formed by controlling the pattern of the center of the annular intrinsic layer 4; meanwhile, by controlling the thickness of the annular intrinsic layer 4, the light confinement in the coverage area of the annular intrinsic layer 4 can be realized, so that the current and light in the long-wavelength vertical cavity surface emitting laser are more concentrated, and the performance of the long-wavelength vertical cavity surface emitting laser is improved.
The detailed structure of the long wavelength vertical cavity surface emitting laser provided by the present invention will be described in detail in the following embodiments of the invention.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a specific long wavelength vertical cavity surface emitting laser according to an embodiment of the present invention.
The present invention is different from the above-described embodiments, and the structure of the long wavelength vertical cavity surface emitting laser is further specifically defined on the basis of the above-described embodiments. The rest of the contents are already described in detail in the above embodiments of the present invention, and are not described herein again.
Referring to fig. 2, in the embodiment of the present invention, the thickness of the annular intrinsic layer 4 is equal to a quarter laser lasing wavelength divided by the refractive index of the annular intrinsic layer 4; the p-type heavily doped layer 5 and the n-type heavily doped layer 6 are both located only inside the annular intrinsic layer 4.
The p-type heavily doped layer 5 and the n-type heavily doped layer 6 are both located only inside the ring-shaped intrinsic layer 4, and the ring-shaped intrinsic layer 4 horizontally surrounds the buried tunnel junction structure formed by the p-type heavily doped layer 5 and the n-type heavily doped layer 6, so as to form effective current confinement. Meanwhile, since the thickness of the annular intrinsic layer 4 is equal to the quarter laser lasing wavelength divided by the refractive index of the annular intrinsic layer 4, the annular intrinsic layer 4 is equivalent to an opposite phase layer, so that the phases of light rays are added and cancelled when the light rays are transmitted in the thickness direction in the annular intrinsic layer 4. At this time, light cannot maintain stable light oscillation in the region covered by the annular intrinsic layer 4, so that the annular intrinsic layer 4 can play a role of light confinement.
According to the long-wavelength vertical cavity surface emitting laser provided by the embodiment of the invention, the thickness of the annular intrinsic layer 4 is equal to the quarter of the laser lasing wavelength divided by the refractive index of the annular intrinsic layer 4, the p-type heavily doped layer 5 and the n-type heavily doped layer 6 are both arranged on the inner side of the annular intrinsic layer 4, and stable light oscillation cannot be maintained due to phase superposition cancellation of light rays passing through the annular intrinsic layer 4, so that the annular intrinsic layer 4 can play a role in light limitation, and the performance of the laser is further improved.
The detailed structure of the long wavelength vertical cavity surface emitting laser provided by the present invention will be described in detail in the following embodiments of the invention.
Referring to fig. 3 and 4, fig. 3 is a schematic structural view of another specific long wavelength vertical cavity surface emitting laser according to an embodiment of the invention; FIG. 4 is a graph of the standing wave distribution in the long wavelength VCSEL of FIG. 3.
The present invention is different from the above-described embodiments, and the structure of the long wavelength vertical cavity surface emitting laser is further specifically defined on the basis of the above-described embodiments. The rest of the contents are already described in detail in the above embodiments of the present invention, and are not described herein again.
Referring to fig. 3, in the embodiment of the present invention, the thickness of the annular intrinsic layer 4 is equal to one-half of the wavelength of the laser standing wave; the p-type heavily doped layer 5 also covers the surface of the annular intrinsic layer 4 on the side opposite to the n-type substrate 1.
The p-type heavily doped layer 5 covers not only the region of the surface of the active layer 3 facing away from the n-type substrate 1, which is located inside the annular intrinsic layer 4, but also the surface of the annular intrinsic layer 4 facing away from the n-type substrate 1. Normally, the p-type heavily doped layer 5 also covers the inner sidewall of the ring-shaped intrinsic layer 4. Correspondingly, the n-type heavily doped layer 6 on the surface of the p-type heavily doped layer 5 opposite to the n-type substrate 1 also covers the region of the surface of the active layer 3 opposite to the n-type substrate 1 and inside the annular intrinsic layer 4, and the surface of the annular intrinsic layer 4 opposite to the n-type substrate 1 and usually also covers the inside wall of the annular intrinsic layer 4. In the present embodiment, the thickness of the annular intrinsic layer 4 is equal to one-half of the wavelength of the standing laser wave.
Referring to fig. 4, when the long wavelength vertical cavity surface emitting laser works, the distribution of standing waves in the cavity is shown in fig. 4, where the extension direction of the longitudinal axis of fig. 4 is the thickness direction of the laser in fig. 3. According to the specific structure of the long-wavelength vertical cavity surface emitting laser, the standing wave distribution in the cavity can be calculated, and then a standing wave wavelength is obtained. The wavelength of the standing wave is typically in the range of 100nm to 500nm, inclusive. In the embodiment of the invention, since the thickness of the annular intrinsic layer 4 is equal to one-half of the standing wave wavelength of the laser, the height difference of half of the standing wave wavelength is formed between the surface of the active layer 3 inside the annular intrinsic layer 4 and the surface of the annular intrinsic layer 4 on the side away from the n-type substrate 1. The surface of the annular intrinsic layer 4, which is opposite to the n-type substrate 1, is usually an antinode of the standing wave, and the optical field intensity is highest at the antinode of the standing wave, so that the corresponding optical loss is also highest; and the surface of the active layer 3 inside the annular intrinsic layer 4 is usually at the node of the standing wave, where the optical field intensity is lowest and the corresponding optical loss is also lowest.
In the embodiment of the present invention, the p-type heavily doped layer 5 and the corresponding n-type heavily doped layer 6 on the surface of the annular intrinsic layer 4 opposite to the n-type substrate 1 are located at the antinodes of the standing waves, so that the light transmitted to the surface of the annular intrinsic layer 4 opposite to the n-type substrate 1 is greatly lost due to the heavily doped layer; on the contrary, the p-type heavily doped layer 5 and the corresponding n-type heavily doped layer 6 inside the ring-shaped intrinsic layer 4 are located at the standing wave node, so that light transmitted inside the ring-shaped intrinsic layer 4 is not greatly lost, and a high loss region and a low loss region based on the ring-shaped intrinsic layer 4 are formed, wherein the low loss region corresponds to the inside of the ring-shaped intrinsic layer 4, and the high loss region corresponds to the coverage region of the ring-shaped intrinsic layer 4, so that light limitation in the transverse direction is formed, and the performance of the laser can be further improved.
According to the long-wavelength vertical cavity surface emitting laser provided by the embodiment of the invention, the thickness of the annular intrinsic layer 4 is equal to one half of the standing wave wavelength of the laser, and the p-type heavily doped layer 5 covers the surface of the annular intrinsic layer 4 on the side opposite to the n-type substrate 1, so that a high loss region and a low loss region can be formed in a laser cavity, wherein the low loss region corresponds to the inner side of the annular intrinsic layer 4, and the high loss region corresponds to the covering region of the annular intrinsic layer 4, so that transverse light limitation is formed, and the performance of the laser can be further improved.
The following describes a method for fabricating a long wavelength vcsel according to the present invention, and the fabrication method described below and the structure of the long wavelength vcsel described above can be referred to correspondingly.
Referring to fig. 5, fig. 5 is a flowchart illustrating a method for fabricating a long wavelength vertical cavity surface emitting laser according to an embodiment of the present invention.
Referring to fig. 5, in an embodiment of the present invention, a method for manufacturing a long wavelength vertical cavity surface emitting laser includes:
s101: an n-type DBR mirror is epitaxially grown on the surface of the n-type substrate.
In this step, an n-type DBR mirror is epitaxially grown on the n-type substrate surface, typically based on an epitaxial growth process. The detailed structure of the n-type substrate and the n-type DBR mirror are described in detail in the above embodiments of the invention, and will not be described herein again.
S102: and epitaxially growing an active layer on the surface of the n-type DBR reflector on the side opposite to the n-type substrate.
In this step, an active layer is epitaxially grown on the surface of the n-type DBR mirror, typically based on an epitaxial growth process. The detailed structure of the active layer is described in detail in the above embodiments of the invention, and will not be described herein again.
S103: and arranging an annular intrinsic layer, a p-type heavily doped layer and an n-type heavily doped layer on one side of the active layer, which is back to the n-type substrate.
In the embodiment of the invention, the annular intrinsic layer is positioned on the surface of the active layer, which faces away from the n-type substrate; the p-type heavily doped layer and the n-type heavily doped layer are at least positioned on the inner side of the annular intrinsic layer, the p-type heavily doped layer at least covers the surface of the active layer positioned on the inner side of the annular intrinsic layer, and the n-type heavily doped layer is positioned on one surface of the p-type heavily doped layer, which faces away from the n-type substrate. The detailed structure of the ring-shaped intrinsic layer, the p-type heavily doped layer and the n-type heavily doped layer has been described in detail in the above embodiments of the present invention, and will not be described herein again.
The details of this step will be described in detail in the following embodiments of the present invention, and will not be described herein again.
S104: and epitaxially growing an n-type conductive layer on the side, opposite to the n-type substrate, of the annular intrinsic layer.
In the embodiment of the invention, the n-type conducting layer covers the n-type heavily doped layer. The detailed structure of the n-type conductive layer is described in detail in the above embodiments of the invention, and will not be described herein again.
In this step, an n-type conductive layer covering the n-type heavily doped layer, the p-type heavily doped layer, and the ring-shaped intrinsic layer is epitaxially grown, typically based on an epitaxial growth process.
S105: and epitaxially growing a p-type DBR mirror on the surface of the n-type conducting layer on the side opposite to the n-type substrate.
In an embodiment of the invention, the p-type DBR mirror and the annular intrinsic layer inner region correspond to each other. The detailed structure of the p-type DBR mirror is described in detail in the above embodiments of the invention, and will not be described herein.
In this step, a p-type DBR mirror is epitaxially grown on the surface of the n-type conductive layer, typically based on an epitaxial growth process.
S106: a p-side electrode electrically connected to the n-type conductive layer and an n-side electrode electrically connected to the n-type substrate are provided to produce a long wavelength vertical cavity surface emitting laser.
The specific structures of the p-side electrode and the n-side electrode are described in detail in the above embodiments of the invention, and are not described herein again. For the specific processes for preparing the p-side electrode and the n-side electrode, reference may be made to the prior art, and further description thereof is omitted here.
In the method for manufacturing a long wavelength vertical cavity surface emitting laser provided by the embodiment of the invention, the manufactured long wavelength vertical cavity surface emitting laser is provided with the annular intrinsic layer on the surface of the active layer opposite to the n-type substrate, the p-type heavily doped layer and the n-type heavily doped layer on the surface of the p-type heavily doped layer opposite to the n-type substrate are arranged on the inner side of the annular intrinsic layer to form the buried tunnel junction structure (BTJ). A tunneling conducting region is formed by the p-type heavily doped layer and the n-type heavily doped layer, current only passes through the tunneling conducting region from the center of the annular intrinsic layer due to the extremely low conductivity of the annular intrinsic layer, and effective current limitation can be formed by controlling the pattern at the center of the annular intrinsic layer; meanwhile, the light limitation in the coverage area of the annular intrinsic layer can be realized by controlling the thickness of the annular intrinsic layer, so that the current and the light in the long-wavelength vertical cavity surface emitting laser are more concentrated, and the performance of the long-wavelength vertical cavity surface emitting laser is improved.
The details of the method for fabricating a long wavelength vertical cavity surface emitting laser according to the present invention will be described in detail in the following embodiments of the invention.
Referring to fig. 6, fig. 6 is a flowchart illustrating a method for fabricating a long wavelength vcsel according to an embodiment of the present invention.
Referring to fig. 6, in an embodiment of the present invention, a method for manufacturing a long wavelength vertical cavity surface emitting laser includes:
s201: an n-type DBR mirror is epitaxially grown on the surface of the n-type substrate.
S202: and epitaxially growing an active layer on the surface of the n-type DBR reflector on the side opposite to the n-type substrate.
This step is substantially the same as S101 to S102 in the above embodiment of the present invention, and for details, reference is made to the above embodiment of the present invention, which is not repeated herein.
S203: and sequentially growing a p-type heavily doped layer and an n-type heavily doped layer in an area selective region on the surface of the active layer opposite to the n-type substrate.
In the embodiment of the invention, the n-type heavily doped layer is only positioned on one side surface of the p-type heavily doped layer, which faces away from the n-type substrate. The detailed structure of the n-type heavily doped layer and the p-type heavily doped layer has been described in the above embodiments of the invention, and will not be described herein again.
In this step, a p-type heavily doped layer and an n-type heavily doped layer are grown on a surface of the active layer opposite to the n-type substrate by a selective area epitaxy process to complete the patterning of the p-type heavily doped layer and the n-type heavily doped layer. For details of the selective area epitaxy process, reference may be made to the prior art, and details thereof are not repeated herein. The p-type heavily doped layer does not cover the active layer entirely, and usually covers only a partial region of the surface of the active layer. The position covered by the p-type heavily doped layer is the position of laser emission in the long wavelength vertical cavity surface emitting laser provided by the embodiment of the invention. In the embodiment of the invention, the n-type heavily doped layer only covers one side surface of the p-type heavily doped layer, which faces away from the n-type substrate, so as to form the buried tunnel junction structure.
S204: and epitaxially growing an annular intrinsic layer surrounding the p-type heavily doped layer and the n-type heavily doped layer on a selective area of the surface of the active layer on the side opposite to the n-type substrate.
In this step, a ring-shaped intrinsic layer surrounding the p-type heavily doped layer and the n-type heavily doped layer in the horizontal direction is grown on the surface of the active layer opposite to the n-type substrate by a selective area epitaxy process to complete the patterning of the ring-shaped intrinsic layer. The detailed structure of the annular intrinsic layer has been described in detail in the above embodiments of the invention, and will not be described herein. For details of the selective area epitaxy process, reference may be made to the prior art, and details thereof are not repeated herein.
It should be noted that the ring-shaped intrinsic layer patterned in this step only horizontally surrounds the p-type heavily doped layer and the n-type heavily doped layer, and usually does not cover a surface of the n-type heavily doped layer facing away from the n-type substrate. In the embodiment of the invention, the thickness of the annular intrinsic layer is generally equal to the quarter laser lasing wavelength divided by the refractive index of the annular intrinsic layer, and meanwhile, because the p-type heavily doped layer and the n-type heavily doped layer are only positioned at the inner side of the annular intrinsic layer, light passing through the annular intrinsic layer cannot maintain stable light oscillation because of phase superposition cancellation, so that the annular intrinsic layer can play a role in light limitation, and the performance of the laser is further improved.
S205: and epitaxially growing an n-type conductive layer on the side, opposite to the n-type substrate, of the annular intrinsic layer.
S206: and epitaxially growing a p-type DBR mirror on the surface of the n-type conducting layer on the side opposite to the n-type substrate.
S207: a p-side electrode electrically connected to the n-type conductive layer and an n-side electrode electrically connected to the n-type substrate are provided to produce a long wavelength vertical cavity surface emitting laser.
S205 to S207 are substantially the same as S104 to S106 in the above embodiment of the invention, and the details have been described in the above embodiment of the invention and will not be described herein again.
According to the preparation method of the long-wavelength vertical cavity surface emitting laser, provided by the embodiment of the invention, the p-type heavily doped layer and the n-type heavily doped layer are patterned, and the annular intrinsic layer surrounding the p-type heavily doped layer and the n-type heavily doped layer in the horizontal direction is grown, so that the long-wavelength vertical cavity surface emitting laser can be prepared. When the thickness of the annular intrinsic layer is equal to the quarter laser lasing wavelength divided by the refractive index of the annular intrinsic layer, stable optical oscillation cannot be maintained because light passing through the annular intrinsic layer is cancelled due to phase superposition, so that the annular intrinsic layer can play a role in optical confinement, thereby further improving the performance of the laser.
The details of the method for fabricating a long wavelength vertical cavity surface emitting laser according to the present invention will be described in detail in the following embodiments of the invention.
Referring to fig. 7, fig. 7 is a flowchart illustrating another specific method for fabricating a long wavelength vcsel according to an embodiment of the present invention.
Referring to fig. 7, in an embodiment of the present invention, a method for manufacturing a long wavelength vertical cavity surface emitting laser includes:
s301: an n-type DBR mirror is epitaxially grown on the surface of the n-type substrate.
S302: and epitaxially growing an active layer on the surface of the n-type DBR reflector on the side opposite to the n-type substrate.
This step is substantially the same as S101 to S102 in the above embodiment of the present invention, and for details, reference is made to the above embodiment of the present invention, which is not repeated herein.
S303: and epitaxially growing an intrinsic layer on the surface of the active layer, which faces away from the n-type substrate.
In this step, an intrinsic layer is grown on the surface of the active layer facing away from the n-type substrate, typically on the basis of an epitaxial growth process, in order to prepare a ring-shaped intrinsic layer in a subsequent step. The material of the intrinsic layer is the same as that of the annular intrinsic layer, which is described in detail in the above embodiments of the present invention, and will not be described again. In the embodiment of the present invention, the thickness of the intrinsic layer is generally equal to one-half of the wavelength of the laser standing wave, so that the thickness of the annular intrinsic layer prepared in the subsequent step is equal to one-half of the wavelength of the laser standing wave.
S304: and etching a preset region on the surface of the intrinsic layer to form the annular intrinsic layer, and exposing a preset region on one side surface of the active layer, which faces away from the n-type substrate.
In this step, a predetermined region of the surface of the intrinsic layer is etched to form an annular intrinsic layer, typically based on a photolithography process. Specifically, the etching depth in this step is usually required to be equal to the thickness of the intrinsic layer, so as to expose a predetermined region of the surface of the active layer opposite to the n-type substrate.
For details of the photolithography process, reference may be made to the prior art, and details thereof are not repeated herein. In an embodiment of the invention, the thickness of the annular intrinsic layer is equal to one-half of the wavelength of the standing wave of the laser.
S305: and epitaxially growing a p-type heavily doped layer and an n-type heavily doped layer on the surface of the annular intrinsic layer in sequence.
In the embodiment of the invention, the p-type heavily doped layer covers the surface of the active layer at the inner region of the annular intrinsic layer and covers the surface of the intrinsic layer opposite to the n-type substrate. It should be noted that, in the embodiment of the present invention, the n-type heavily doped layer is located on the surface of the p-type heavily doped layer opposite to the n-type substrate, and at this time, the n-type heavily doped layer also covers the surface of the active layer located in the inner region of the ring-shaped intrinsic layer and covers the surface of the intrinsic layer opposite to the n-type substrate. The detailed structure of the n-type heavily doped layer and the p-type heavily doped layer are described in the above embodiments of the invention, and will not be described herein again.
The p-type doped layer not only covers the surface of the active layer exposed at the inner side of the annular intrinsic layer, but also covers the surface of the annular intrinsic layer, which faces away from the n-type substrate. At this time, when the thickness of the ring intrinsic layer is equal to one half of the standing wave wavelength of the laser, the p-type heavily doped layer and the corresponding n-type heavily doped layer on the surface of the ring intrinsic layer opposite to the n-type substrate are located at the antinode of the standing wave, so that the light transmitted to the surface of the ring intrinsic layer opposite to the n-type substrate is greatly lost due to the heavily doped layer; on the contrary, because the p-type heavily doped layer and the corresponding n-type heavily doped layer on the inner side of the annular intrinsic layer are positioned at the standing wave node, light transmitted on the inner side of the annular intrinsic layer is not greatly lost, so that a high loss region and a low loss region based on the annular intrinsic layer are formed, wherein the low loss region corresponds to the inner side of the annular intrinsic layer, and the high loss region corresponds to the covering region of the annular intrinsic layer, so that transverse light limitation is formed, and the performance of the laser can be further improved.
S306: and epitaxially growing an n-type conductive layer on the side, opposite to the n-type substrate, of the annular intrinsic layer.
S307: and epitaxially growing a p-type DBR mirror on the surface of the n-type conducting layer on the side opposite to the n-type substrate.
S308: a p-side electrode electrically connected to the n-type conductive layer and an n-side electrode electrically connected to the n-type substrate are provided to produce a long wavelength vertical cavity surface emitting laser.
S306 to S308 are substantially the same as S104 to S106 in the above embodiment of the invention, and the details have been described in the above embodiment of the invention and will not be described herein again.
According to the preparation method of the long-wavelength vertical cavity surface emitting laser, provided by the embodiment of the invention, the long-wavelength vertical cavity surface emitting laser can be prepared by firstly patterning the intrinsic layer to form the annular intrinsic layer and then growing the p-type heavily doped layer and the n-type heavily doped layer. When the thickness of the annular intrinsic layer is equal to one half of the standing wave wavelength of the laser, a high-loss region and a low-loss region based on the annular intrinsic layer are formed, wherein the low-loss region corresponds to the inner side of the annular intrinsic layer, and the high-loss region corresponds to the covering region of the annular intrinsic layer, so that the transverse light limitation is formed, and the performance of the laser can be further improved.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The present invention provides a long wavelength vcsel and a method for fabricating a long wavelength vcsel. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (10)

1. A long wavelength vertical cavity surface emitting laser, comprising:
an n-type substrate;
an n-type DBR mirror located on the n-type substrate surface;
an active layer on a surface of the n-type DBR mirror facing away from the n-type substrate;
the annular intrinsic layer is positioned on the surface, facing away from the n-type substrate, of the active layer;
the p-type heavily doped layer is at least positioned on the inner side of the annular intrinsic layer, and the n-type heavily doped layer is at least positioned on the inner side of the annular intrinsic layer; the p-type heavily doped layer at least covers the surface of the active layer at the inner side of the annular intrinsic layer, and the n-type heavily doped layer is positioned at the surface of the p-type heavily doped layer, which faces away from the n-type substrate;
the n-type conducting layer is positioned on one side, back to the n-type substrate, of the annular intrinsic layer; the n-type conducting layer covers the n-type heavily doped layer;
the p-type DBR reflector is positioned on one side surface, opposite to the n-type substrate, of the n-type conducting layer; the p-type DBR reflector corresponds to the inner side region of the annular intrinsic layer;
a p-side electrode electrically connected to the n-type conductive layer, and an n-side electrode electrically connected to the n-type substrate.
2. The long wavelength vertical cavity surface emitting laser of claim 1, wherein an inner side of said annular intrinsic layer is cylindrical; the p-type DBR reflector is cylindrical.
3. The long wavelength vertical cavity surface emitting laser of claim 2, wherein said dopant of said p-type heavily doped layer is carbon, and said p-type heavily doped layer is doped with a concentration ofThe value range is 5 multiplied by 1019cm-3To 1X 1020cm-3Inclusive of the endpoint values; the doping agent of the n-type heavily doped layer is zinc, and the value range of the doping concentration of the n-type heavily doped layer is 1 multiplied by 1019cm-3To 3X 1019cm-3Inclusive.
4. The long wavelength vertical cavity surface emitting laser of claim 3, wherein the thickness of the p-type heavily doped layer ranges from 8nm to 15nm, inclusive; the thickness of the n-type heavily doped layer ranges from 15nm to 30nm, inclusive.
5. The long wavelength vertical cavity surface emitting laser according to claim 1, wherein said p-side electrode is located on a surface of said n-type conductive layer facing away from said n-type substrate, and said n-side electrode is located on a surface of said n-type substrate facing away from said n-type DBR mirror.
6. The long wavelength vertical cavity surface emitting laser according to any of claims 1 to 5, wherein the thickness of said annular intrinsic layer is equal to a quarter laser lasing wavelength divided by the refractive index of said annular intrinsic layer; the p-type heavily doped layer and the n-type heavily doped layer are both only positioned on the inner side of the annular intrinsic layer.
7. The long wavelength vertical cavity surface emitting laser according to any of claims 1 to 5, wherein the thickness of said annular intrinsic layer is equal to one-half of the laser standing wave wavelength; the p-type heavily doped layer also covers one side surface of the annular intrinsic layer, which faces away from the n-type substrate.
8. A method of fabricating a long wavelength vertical cavity surface emitting laser, comprising:
epitaxially growing an n-type DBR mirror on the surface of the n-type substrate;
epitaxially growing an active layer on the surface of one side, back to the n-type substrate, of the n-type DBR reflector;
arranging an annular intrinsic layer, a p-type heavily doped layer and an n-type heavily doped layer on one side of the active layer, which faces away from the n-type substrate; the annular intrinsic layer is positioned on the surface, facing away from the n-type substrate, of the active layer; the p-type heavily doped layer and the n-type heavily doped layer are at least positioned on the inner side of the annular intrinsic layer, the p-type heavily doped layer at least covers the surface of the active layer positioned on the inner side of the annular intrinsic layer, and the n-type heavily doped layer is positioned on one surface of the p-type heavily doped layer, which faces away from the n-type substrate;
epitaxially growing an n-type conducting layer on one side, back to the n-type substrate, of the annular intrinsic layer; the n-type conducting layer covers the n-type heavily doped layer;
epitaxially growing a p-type DBR reflector on the surface of one side, opposite to the n-type substrate, of the n-type conducting layer; the p-type DBR reflector corresponds to the inner side region of the annular intrinsic layer;
and arranging a p-surface electrode electrically connected with the n-type conducting layer and an n-surface electrode electrically connected with the n-type substrate to manufacture the long-wavelength vertical cavity surface emitting laser.
9. The method of claim 8, wherein the disposing of the annular intrinsic layer, the p-type heavily doped layer, and the n-type heavily doped layer on the side of the active layer facing away from the n-type substrate comprises:
sequentially and selectively growing a p-type heavily doped layer and an n-type heavily doped layer in an area on one side surface of the active layer, which is opposite to the n-type substrate; the n-type heavily doped layer is only positioned on one side surface of the p-type heavily doped layer, which faces away from the n-type substrate;
and epitaxially growing an annular intrinsic layer surrounding the p-type heavily doped layer and the n-type heavily doped layer on a selected area of the surface of one side of the active layer, which is back to the n-type substrate.
10. The method of claim 8, wherein the disposing of the annular intrinsic layer, the p-type heavily doped layer, and the n-type heavily doped layer on the side of the active layer facing away from the n-type substrate comprises:
epitaxially growing an intrinsic layer on the surface of one side, back to the n-type substrate, of the active layer;
etching a preset region on the surface of the intrinsic layer to form an annular intrinsic layer, and exposing a preset region on one side surface of the active layer, which faces away from the n-type substrate;
sequentially epitaxially growing a p-type heavily doped layer and an n-type heavily doped layer on the surface of the annular intrinsic layer; the p-type heavily doped layer covers the surface of the active layer at the inner side area of the annular intrinsic layer and covers the surface of the intrinsic layer, which faces away from the n-type substrate.
CN201911275025.1A 2019-12-12 2019-12-12 Long wavelength vertical cavity surface emitting laser and preparation method thereof Pending CN110932092A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112510130A (en) * 2020-12-02 2021-03-16 武汉大学 Design and manufacturing method of blue light Mico-LED chip with flip-chip structure

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112510130A (en) * 2020-12-02 2021-03-16 武汉大学 Design and manufacturing method of blue light Mico-LED chip with flip-chip structure

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