CN115693399A - Semiconductor laser device, manufacturing method and application thereof - Google Patents

Abstract

The present disclosure provides a semiconductor laser and a method of fabricating the same, the laser including: a substrate; a semiconductor structure formed on a substrate, including first and second distributed Bragg reflectors, first and second cladding layers, and an active layer; and a first confinement layer formed on the active layer and/or a second confinement layer formed under the active layer; the limiting layer limits N adjacent sub-light-emitting areas in the active layer, the N adjacent sub-light-emitting areas form a coherent coupling light-emitting unit, and N is an integer larger than or equal to 3. The present disclosure helps to achieve one of the following effects: the current spreading is not uniform, coherent coupling output is obtained, the light beam quality is improved, and high-degree compact arrangement and accurate limitation are provided.

Description

Semiconductor laser device, manufacturing method and application thereof

Technical Field

The present disclosure relates to semiconductor lasers, and more particularly, to vertical cavity surface emitting semiconductor lasers, methods of fabrication, and applications thereof.

Background

Semiconductor lasers, particularly vertical cavity surface emitting lasers, are ideal surface emitting light sources, have the characteristics of good beam quality, single longitudinal mode, low threshold value, easiness in two-dimensional integration and the like, and have increasingly wide application in the fields of data transmission, sensing, optical interconnection, virtual Reality (VR)/Augmented Reality (AR), laser printing, optical signal processing and the like.

In most fields, such as the technical fields of target shooting, laser ranging, image processing, laser radar, sensing and the like, the requirements on the beam quality of a Vertical Cavity Surface Emitting Laser (VCSEL) are high. The existing VCSEL realizes coherent coupling output by forming a coherent array, the coherent coupling VCSEL array has the potential of outputting a light beam near the diffraction limit, coherent superposition of light emitting units in the array can concentrate energy at an axial center, so that the axial beam has a narrow far-field divergence angle and uniform near-field distribution, and the larger the array size is, the better the light beam quality is, which has become a hotspot of research at present.

For coherent coupling output of a VCSEL array, structures such as a photonic crystal, a built-in inverse waveguide, a phase adjustment layer, and a metal grid electrode have been designed, in order to implement coherent coupling output, a small distance between light emitting units in the coherent array is required to ensure that light emitted from the light emitting units can be coherently coupled, but at the same time, in order to form current limitation between the light emitting units, a certain distance between the light emitting units must be ensured, which requires a compromise. Therefore, the density of the cells in the current VCSEL coherent array cannot be further improved, the output power of the array cannot be further improved, and the beam quality and the threshold current characteristic of the array cannot be further improved.

Aiming at the technical problems, the problems of uneven current expansion and incoherent sub-light emitting areas are solved by utilizing the physical characteristic of carrier injection in the semiconductor laser and through a current limiting mode with a specific structure, coherent coupling output can be obtained, the light beam quality of the semiconductor laser is greatly improved, the technical problems of uneven current expansion, incoherent light emitting points and unstable high-power output are solved, coherent coupling output is obtained, high-degree close arrangement and accurate limitation are realized, and the semiconductor laser has a wide application prospect.

Disclosure of Invention

A brief summary of the disclosure is provided below in order to provide a basic understanding of some aspects of the disclosure. It should be understood that this summary is not an exhaustive overview of the disclosure. It is not intended to identify key or critical elements of the disclosure or to delineate the scope of the disclosure. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

According to another aspect of the present disclosure, there is provided a semiconductor laser including:

a substrate; a semiconductor structure formed on a substrate, including first and second distributed Bragg reflectors, first and second cladding layers, and an active layer; and a first current confinement layer formed on the active layer and/or a second current confinement layer formed under the active layer; the current confinement layer defines N adjacent sub-light-emitting regions in the active layer, the N adjacent sub-light-emitting regions forming a coherent coupling light-emitting unit, wherein N is an integer greater than or equal to 3.

Further, the coherent coupling light-emitting unit is a pattern formed by N arc segments which are connected end to end when viewed from the top.

Further wherein the first and/or second current confinement layers are formed by ion implantation.

Further wherein a mesa structure is formed on the semiconductor structure, the mesa structure exposing sides of the first and/or second confinement layers, the first and/or second confinement layers being formed by lateral oxidation.

Further, in the pattern formed by connecting the N arc-shaped segments, the distance from the center of the pattern to the edge of the pattern is 3-10 microns.

Further wherein said N arc segments are 3-8 arc segments.

Further, the center of the mesa structure is provided with a groove with a symmetrical or asymmetrical cross section.

Further wherein said first and second confinement layers further comprise an insulating region formed around said recess.

Further wherein the graphic is selected from the group consisting of: circular, isosceles triangle, square, regular hexagon, octagon or asymmetric polygon formed by arc segments.

Further, the light emitting device further comprises a first electrode formed on the coherent coupling light emitting unit.

Further, the first electrode is separately arranged or integrally arranged.

According to another aspect of the present disclosure, there is provided a method of fabricating a semiconductor laser, including: providing a substrate; forming a stacked structure of a plurality of semiconductor materials on the substrate; the laminated structure comprises an active layer and an Al X Ga 1-X As layer formed on and/or under the active layer, wherein X is in the range of 0.95-0.99; locally converting the Al x Ga 1-x As layer into an electrical insulation property to form a current confinement layer, wherein the current confinement layer defines N adjacent sub-light-emitting regions in the active layer, the N adjacent sub-light-emitting regions form a coherent coupling light-emitting unit, and N is an integer greater than or equal to 3.

Further wherein the step of locally transforming the Al x Ga 1-x As layer to electrically insulating properties comprises: etching the laminated structure to form a mesa structure on the substrate; oxidizing the Al x Ga 1-x As layer, and insulating the periphery of the Al x Ga 1-x As layer exposed by the mesa structure to define the coherent coupling light-emitting unit in the mesa structure.

Further, the mesa structure is formed by connecting N arcs end to end, and N is an integer greater than or equal to 3.

Further, a groove structure is formed in the center of the mesa structure in an etching mode.

Further, when the Al x Ga 1-x As layer is oxidized, the exposed part of the Al x Ga 1-x As layer of the groove structure is insulated at the same time.

Further, the step of locally converting the Al x Ga 1-x As layer into an electrical insulating property includes: and carrying out ion implantation on the substrate comprising the laminated structure, so that the position corresponding to the Al x Ga 1-x As layer is converted into an insulating layer.

Further wherein the laminated structure further comprises: first and second distributed Bragg reflectors, first and second cladding layers are formed on the substrate.

Further, the laminated structure further comprises a buffer layer.

Further, a first electrode is formed on the second distributed bragg reflector, and a second electrode is formed on the substrate.

Further wherein the first electrode is formed in a discrete or continuous form.

According to still another aspect of the present disclosure, an electronic device is provided, which includes the aforementioned semiconductor laser.

Furthermore, the electronic device is a mobile phone, a sensor, a laser radar, an optical communication module or a laser printer. The scheme of the present disclosure can at least help to realize one of the following effects: the problems that current expansion is not uniform and each sub-luminous area cannot be coherently coupled are solved, coherent coupling output is obtained, the beam quality of the semiconductor laser is greatly improved, uniform current expansion is achieved, coherent coupling output is obtained, and high-degree tight arrangement and accurate limitation are achieved.

Drawings

The above and other objects, features and advantages of the present disclosure will be more readily understood from the following detailed description of the present disclosure with reference to the accompanying drawings. The drawings are only for the purpose of illustrating the principles of the disclosure. The dimensions and relative positioning of the elements in the figures are not necessarily drawn to scale.

Fig. 1 shows a schematic diagram of the distribution of laser spots at currents I1, I2, where I1< I2;

FIG. 2 shows calculated near-field and far-field patterns (from a to e, with increasing operating current) of the laser parallel to the junction plane;

3-4 show schematic diagrams of semiconductor laser structures according to a first embodiment;

fig. 5 shows a flow chart of a method of fabricating a semiconductor laser structure according to a second embodiment;

6-8 show schematic diagrams of semiconductor laser structures according to a third embodiment;

fig. 9 shows a flowchart of a method of fabricating a semiconductor laser structure according to a fourth embodiment.

Detailed Description

Exemplary disclosures of the present disclosure will be described hereinafter with reference to the accompanying drawings. In the interest of clarity and conciseness, not all features of an implementation of the present disclosure are described in the specification. It will be appreciated, however, that in the development of any such actual implementation of the disclosure, numerous implementation-specific decisions may be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.

Here, it should be further noted that, in order to avoid obscuring the present disclosure by unnecessary details, only device structures closely related to the scheme according to the present disclosure are shown in the drawings, and other details not so related to the present disclosure are omitted.

It is to be understood that the disclosure is not limited to the described embodiments, as described below with reference to the drawings. Herein, features between different implementations may be replaced or borrowed where feasible, and one or more features may be omitted in one implementation.

Generally, a semiconductor laser has no change in refractive index in a plane parallel to a pn junction of a semiconductor in a direction parallel to the plane of the pn junction because the semiconductor material is the same, and thus, a mode in which the semiconductor laser excites light cannot be well limited.

Taking GaAs-based laser as an example, when a semiconductor laser is operated, with current injection, generation of photons in an active layer is induced, so that a material has a difference between gain and loss, a refractive index of the material needs to be represented by a complex number, wherein a change of an imaginary part is caused by the gain and loss, and plays a main role in controlling a lasing mode. Under the condition that the current is not limited, the gain and the loss can be mutually converted, the laser gain is that stimulated emission photons (generated by carrier recombination in an active layer) are generated, the carrier concentration is inevitably reduced, when the stimulated emission photons are reduced to be below the threshold carrier concentration, the stimulated emission photons stop generating, but the nearby place which originally does not reach the threshold carrier concentration reaches the lasing threshold along with the increase of the current, and the stimulated emission photons start to emit laser photons due to mode competition, so that the spatial hole burning is formed. Spatial hole burning results in a periodic variation of the imaginary part of the index of refraction, the width of which is the diffusion length L of the carriers. Which conforms to the following equations (1) and (2), and corresponds to GaAs based materials, approximately 3-5 microns.

Where D is the diffusion coefficient and τ is the carrier lifetime.

Since the periodic self-focusing effect is generated due to the periodic change of the imaginary part of the refractive index, the light is arranged in an array mode on a plane parallel to the pn junction, the whole laser is the integral effect of a plurality of laser light spots, and the light spot emission schematic diagram is shown in fig. 1. With the increase of current injection, each lasing spot moves, and because the spot position changes constantly, the light emitted by adjacent lasing spots cannot form coherent coupling, so that the adjacent lasing spots cannot form a coherent coupling light-emitting unit.

Careful study of the lasing spot revealed that the spot conformed to equation (3),

wherein: e (y, z) is the field strength of the emergent light, y is the direction parallel to the junction, z is the emergent direction, and the expression of the field strength is shown in formula (4):

substituting the formula (4) into the formula (3),

since the propagation direction is the z direction, the light intensity fluctuates in the z direction and is a sine wave fluctuation, so that: v (y, z) = A (y) e ^δz And obtaining an electric field equation parallel to the junction direction through a series of calculations as shown in formula (5).

And (4) calculating according to the formula (5) and further according to the formulas (6) and (7) to obtain the near-field and far-field patterns.

Near field pattern

I(y)∝|v(y)| ² Formula (6)

Far field pattern

I(θ)∝cos ² θ|F(θ) ² Equation (7)

Wherein the content of the first and second substances,

from the above analysis, near-field and far-field patterns of light emission of spots of the GaAs-based laser parallel to the plane of the pn junction can be obtained by calculation, as shown in fig. 2, in which the left part is the light emission intensity of the near-field pattern spot, the right part is the divergence angle of the far-field pattern, y is the distance from the center of the pn junction, and from (a) to (e), the operating current gradually increases. It can be seen that, when the current is small, the near field pattern is two separate laser light spots, and since the light spots are far away from each other, coherent coupling does not occur, so that the divergence angle of the far field pattern is large, and the far field pattern is displayed as two separate light spots (corresponding to (a) in fig. 2).

Based on the above characteristics of the laser, the inventors propose a coherent coupling dense-mode vertical cavity surface emitting semiconductor laser scheme in which a confinement layer in a device structure is formed as a permanent, stable insulating layer by current confinement above or below an active layer so as not to vary with current. The uninsulated portions are not confined, thereby forming a current path.

Based on the analysis of the spatial hole burning and the carrier diffusion characteristics, firstly, the current of each sub-light emitting region is limited through a current limiting layer, so that the light spot of each sub-light emitting region in the VCSEL laser is controlled not to move, the current limiting pattern is not in a conventional circular or rhombic shape, a current limiting scheme is designed by calculating the number of the light spots of the sub-light emitting regions and the distance between the light spots of the sub-light emitting regions, so that the light spots of the sub-light emitting regions can be normally stimulated to emit photons when the current I1 is injected, when the carrier concentration is reduced, current injection cannot be formed nearby, the carrier concentration is always low, the light cannot be stimulated to emit light, the original light spots supplement through the current injection to enable the carrier concentration to reach a threshold value again, and the light spots of the light emitting regions can continuously emit light at the original light spots when the current I2, and therefore the light spots of the light emitting regions are guaranteed not to move, wherein I1 is less than I2.

Secondly the distance between the spots of the sub-luminescent areas is controlled by current limitation to achieve their strong and weak coupling.

Such current confinement may be achieved by ion implantation or lateral oxidation of the current confinement layer above or below the active layer.

First embodiment

A semiconductor laser and a method of manufacturing the same according to a first embodiment are described with reference to fig. 3 to 4.

As shown in fig. 3 to 4, in the first embodiment, the semiconductor laser is a vertical cavity surface emitting semiconductor laser, and includes a substrate 100, a material of the substrate 100 may be selected according to actual needs, and the disclosure does not limit a specific material of the substrate 100. Illustratively, the material of the substrate 100 may be a iii-v material or a iv material, such as a gallium arsenide (GaAs) substrate, an indium phosphide (InP), a silicon (Si) substrate, or a silicon carbide (SiC) substrate, and typically the gallium arsenide (GaAs) layer may be an n-type gallium arsenide substrate.

Optionally, a buffer layer 101 is provided on the substrate 100, and the adaptive thickness and the corresponding doping concentration are designed according to the requirements of specific devices, so as to achieve a reasonable resistance value. Illustratively, the buffer layer can be deposited on the n-type gallium arsenide substrate, and has a thickness of 100-300 nm and a doping concentration of 1 × 10 ¹⁷ cm ^-3 -7×10 ¹⁸ cm ^-3 The buffer layer may be doped with the same type according to the doping type of the substrate.

The buffer layer 101 has a first distributed bragg reflector 102 thereon, and the first distributed bragg reflector 102 may be formed by alternately stacking a plurality of first sublayers and a plurality of second sublayers. Illustratively, the first dbr 102 is n-doped when the substrate 100 is n-doped GaAs. Further, a first sub-layer in the first dbr 102 layer is made of n-type Al x Ga 1-x As, and a second sub-layer is made of Al y Ga 1-y As, where x ranges from 0 to 0.5 and y ranges from 0.5 to 1, and the number of the first sub-layer and the second sub-layer may be 10 to 40 respectively, depending on the material type and the composition, and typically may be 20 to 30.

On the first DBR 102, there is a first cladding layer 103, which may be Al for GaAs based materials _x Ga _1-x As/Al _y Ga _1-y As, wherein x ranges from 0 to 0.5, and y ranges from 0.5 to 1, and the first cladding layer is 1 x 10 ¹⁷ cm ^-3 To 5X 10 ¹⁸ cm ^-3 Of n-type material layer of doping level.

Next, an active layer 104, which is formed on the first cladding layer 103, is exemplified by a quantum well or quantum dot structure that may be composed of 1-9 pairs of AlGaAs/GaAs for GaAs-based materials, where the Al composition may be 0.1-0.9, and a quantum well or quantum dot structure that may be composed of 1-9 pairs of InGaAsP/InP for InP-based materials, depending on the desired output wavelength and material type of the laser structure.

A second cladding layer 105 further formed on the active layer 104, the second cladding layer 105 being similar to the first cladding layer 103 in arrangement and being made of Al x Ga 1-x As/Al y Ga 1-y As, wherein x is in the range of 0 to 0.5, y is in the range of 0.5 to 1, and the second cladding layer is 1 × 10 ¹⁷ cm ^-3 To 5X 10 ¹⁸ cm ^-3 A p-type material layer of doping level.

By setting the thicknesses of the first cladding layer 103, the active layer 104, and the second cladding layer 105, a desired optical gain can be obtained.

Further, a first current confinement layer 106 is formed on the second cladding layer, and typically, the first current confinement layer 106 is formed by converting a part of the material into an insulating layer by ion implantation to realize current confinement.

More preferably, the injection current limitation of the VCSEL may be achieved by forming a mesa by etching to expose a side surface of Al X Ga 1-xaas of a high aluminum composition, and laterally oxidizing the Al X Ga 1-xaas of the high aluminum composition to form an oxidation limiting layer, wherein X ranges from 0.95 to 0.99, the lateral oxidation oxidizing a periphery of the Al X Ga 1-xaas of the high aluminum composition to an insulating alumina, such that an inner unoxidized portion serves As a current path for carriers, and the oxidized portion also serves As an optical waveguide limitation due to a change in refractive index, and the inner oxidized portion serves As an exit hole of the VCSEL, wherein each of the exit hole-formed sub-emitting regions may have a diameter of 2 to 8 μm. Specifically, the first current confinement layer 106 provides current confinement and optical confinement through conductivity changes and refractive index changes, thereby forming a smaller range of first conductive regions over the active layer 104. The current limiting layer is arranged at the periphery of the first conductive area, so that N sub-light emitting areas are defined in the first conductive area, and a coherent coupling light emitting unit is defined by the N adjacent sub-light emitting areas, for example, the outer contour of the coherent coupling light emitting unit formed by the sub-light emitting areas is a figure formed by N segments of circular arcs adjacent end to end when viewed from the top, and the average aperture of the figure is 2-8um.

The number of N may be set to an integer greater than or equal to 3 as required. As an example of the coherent coupling light emitting unit, the sub-light emitting areas are three circular arc-shaped sub-light emitting areas connected end to end as viewed in a plan view. The current limiting layer is used for limiting current injection, so that the region where the current flows in is in accordance with the diffusion shape of a current carrier, the position of a light emitting point can be clamped and fixed, the current is injected into each light emitting point in the vertical cavity surface emitting laser structure at the same time to ensure the same phase, the coherent output purpose is achieved, strong coherent coupling is achieved among a plurality of adjacent sub light emitting regions to form a coherent coupling light emitting unit, the output mode is stable, stable single transverse mode output is achieved, and the quality and the power of output light beams are greatly improved.

Then, a second distributed bragg reflector 107 is further formed on the first current confinement layer 106, and correspondingly, the second distributed bragg reflector 107 is also formed by alternately stacking a plurality of third sublayers and a plurality of fourth sublayers. Illustratively, the second distributed bragg reflector 107 is p-doped when the substrate 100 is n-doped GaAs. Further, a third sub-layer of the layers of the second distributed bragg reflector 107 is made of p-type Al x Ga 1-x As, and a fourth sub-layer is made of Al y Ga 1-y As, wherein x ranges from 0 to 0.5, y ranges from 0.5 to 1, the number of the third sub-layer and the fourth sub-layer can be 10-40, respectively, and the number of the typical first sub-layer and the second sub-layer can be 20-30.

It is further understood that a second current confinement layer 108 may also be formed below the first cladding layer 103. The second current confinement layer 108 is provided corresponding to the first current confinement layer 106. It is also understood that the second current confinement layer may be formed anywhere between the first distributed bragg reflector and the active layer, and similarly, the first current confinement layer may be formed anywhere between the active layer and the second distributed bragg reflector.

It is further understood that the first current confinement layer and the second current confinement layer may be formed separately, or the first current confinement layer and the second current confinement layer may be formed of outermost layers of the second distributed bragg mirror and the first distributed bragg mirror, respectively, which are closest to the active layer.

Further, a first electrode 109 may be formed on the second distributed bragg reflector, and the first electrode may partially contact each of the light emitting regions, or the first electrode may surround the light emitting unit; and forming a second electrode 110 on the back surface of the substrate 100, and similarly, the second electrode may be integrally disposed on the back surface or disposed corresponding to each light emitting cell. The electrode material is selected from one or more of Ti, au, ge, ni, pt, pd and alloy thereof.

Second embodiment

A manufacturing method for manufacturing the semiconductor laser device of the first embodiment will now be described in detail with reference to fig. 5.

Step 1: a substrate 100 is provided.

Step 2: a buffer layer may be formed on the substrate 100 by an epitaxial deposition process of Metal Organic Chemical Vapor Deposition (MOCVD) or a Liquid Phase Epitaxy (LPE) and molecular beam epitaxy or other crystal growth processes. The thickness of the buffer layer is 100-300 nm, and the doping concentration is 1 × 10 ¹⁷ cm ^-3 -7×10 ¹⁸ cm ^-3 The buffer layer may be doped with the same type according to the doping type of the substrate.

And 3, step 3: a plurality of first sublayers and a plurality of second sublayers are alternately epitaxially formed on the buffer layer 101 to form the first dbr 102. The number of the first sub-layer and the second sub-layer may be 10-40 respectively, and the number of the first sub-layer and the second sub-layer may be 20-30 typically.

And 4, step 4: forming a first cladding layer 103 on the first distributed Bragg reflector 102, wherein the doping concentration of the first cladding layer 103 can be 1 × 10 according to the device requirements and the type of the substrate ¹⁷ cm ^-3 To 5X 10 ¹⁸ cm ^-3 Of n-type material layer of doping level.

And 5: optionally, an Al X Ga 1-X As layer is formed between the first dbr 102 and the first cladding layer 103, wherein X is in the range of 0.95-0.99.

Step 6: an active layer 104 is formed on the Al x Ga 1-x As layer, and the active layer 104 may be selectively formed in a quantum well or quantum dot structure of 1-9 pairs of AlGaAs/GaAs, wherein the Al composition may be 0.1-0.9, and for InP-based materials, the active layer may be exemplified by a quantum well or quantum dot structure of 1-9 pairs of InGaAsP/InP.

And 7: a second cladding layer 105 is formed on the active layer 104, the second cladding layer 105 being similar to the growth process of the first cladding layer 103, but having a doping type opposite to that of the first cladding layer 103.

And 8: an Al X Ga 1-xAs layer is formed on the second clad layer 105, wherein X is in the range of 0.95-0.99.

And step 9: and a plurality of third sublayers and a plurality of fourth sublayers are alternately epitaxially formed on the Al x Ga 1-x As layer to form the second distributed bragg reflector 107. The number of the third sub-layer and the fourth sub-layer may be 10-40 respectively, and the number of the typical first sub-layer and the second sub-layer may be 20-30, and the doping type is opposite to that of the first distributed bragg reflector.

Step 10: and etching the laminated structure to form a mesa structure formed by connecting N circular arcs, wherein N is 3 for example. The mesa structure exposes the side face of the Al x Ga 1-x As layer, then the Al x Ga 1-x As layer is laterally oxidized, so that a first and/or second oxidized current limiting layer which plays a role in inhibiting current is formed, the oxidized current limiting layer surrounds the active layer to limit each adjacent sub-light emitting region, and then the sub-light emitting regions are combined to form a coherent coupling light emitting unit, so that the VCSEL is densified, and meanwhile, the output power and the beam quality are greatly improved.

Optionally, if the current confinement layer is formed by ion implantation instead of lateral oxidation, the step 10 does not need to form a mesa structure by etching, and directly controls the dose and implantation energy of ion implantation, so that the electrical property of the confinement layer is converted into insulation by ion implantation at the periphery of the corresponding position of the confinement layer, and the ion implantation current confinement layer is formed to achieve current implantation confinement.

Step 11: a metal layer is formed on the second dbr 107, and a first electrode 109 is formed by high temperature annealing, which may be formed by sputtering or other processes.

Step 12: and a second electrode 110 is formed on the back surface of the substrate 100. The substrate is thinned, and then a metal layer is formed thereon, and high temperature annealing is performed to realize good ohmic contact, thereby forming the second electrode 110.

It is understood that the second oxidation current confinement layer 108 is provided corresponding to the first oxidation current confinement layer 106. It is also understood that the second oxidation current confinement layer may be formed anywhere between the first dbr and the active layer, and similarly, the first oxidation current confinement layer may be formed anywhere between the active layer and the second dbr.

Third embodiment

As shown in fig. 6, the light emitting unit is different from the first embodiment only in that the center of the light emitting unit has a groove having a symmetrical or asymmetrical pattern as viewed from a top view. Illustratively, the pattern may be a circle, an equilateral triangle, a square, or a symmetrical pattern having a curvature in the same/opposite direction as the outer curvature of the light emitting unit, and the aperture may be in the range of 1 to 20 μm.

The outer contour of the cross section of the N sub-light emitting areas is an oxidation current limiting layer formed by connecting N circular arcs end to end, and the outer contour of the groove is also an oxidation current limiting layer formed by a closed curve.

The number of N may be set to be greater than or equal to three as required. Illustratively, the light-emitting unit may be a light-emitting unit formed by connecting three to eight circular arcs, as shown in fig. 7 to 8, when viewed from a top view. Wherein the distance from the center of the trench to the light emitting unit is in the range of 3-10 micrometers.

Fourth embodiment

A semiconductor laser and a method of fabricating the same according to a fourth embodiment are described with reference to fig. 9.

Only differs from the second embodiment in that step 10 is replaced by step 10':

step 10': the stacked structure is etched to form a mesa structure of a light-emitting unit formed by connecting N arcs, and a groove structure with symmetrical patterns is formed in the center of the mesa structure, the mesa structure and the groove structure expose the side face of the Al x Ga 1-x As layer, then the Al x Ga 1-x As layer is laterally oxidized through the outer side of the mesa structure and the groove structure, and further a first oxidation current limiting layer and/or a second oxidation current limiting layer which play a role in inhibiting current are formed, the oxidation current limiting layer surrounds the active layer and the groove to limit adjacent sub-light-emitting areas, and then the sub-light-emitting areas are combined to form a coherent coupling light-emitting unit, so that the output power and the beam quality are greatly improved while the densification is realized.

Fifth embodiment

An electronic device may be one of a data transmission device, a sensor, an optical interconnection module, an optical communication module, a Virtual Reality (VR)/Augmented Reality (AR) device, a laser printer, a mobile phone. The electronic device may include any of the semiconductor lasers in the above embodiments.

The disclosure has been described with reference to specific embodiments, but it will be apparent to those skilled in the art that these descriptions are illustrative and not intended to limit the scope of the disclosure. Various modifications and alterations of this disclosure will become apparent to those skilled in the art from the spirit and principles of this disclosure, and such modifications and alterations are also within the scope of this disclosure.

Claims (23)

1. A semiconductor laser comprising:

a substrate;

a semiconductor structure formed on a substrate, including first and second distributed Bragg reflectors, first and second cladding layers, and an active layer;

and a first current confinement layer formed on the active layer and/or a second current confinement layer formed under the active layer;

the current confinement layer defines N adjacent sub-luminescent regions in the active layer, the N adjacent sub-luminescent regions forming a coherent coupling light emitting unit, wherein N is an integer greater than or equal to 3.

2. The semiconductor laser of claim 1, wherein the coherently coupled light emitting cells are patterned from N segments of arc segments end to end when viewed from above.

3. The semiconductor laser of claim 1, wherein said first and/or second current confinement layers are formed by ion implantation.

4. The semiconductor laser of claim 1, wherein a mesa structure is formed on the semiconductor structure, the mesa structure exposing sides of the first and/or second confinement layers, the first and/or second confinement layers being formed by lateral oxidation.

5. The semiconductor laser of claim 2, wherein in the pattern formed by the connection of N arcuate segments, the center of the pattern is located 3-10 microns from the edge of the pattern.

6. The semiconductor laser of claim 2, wherein said N arc segments are 3-8 arc segments.

7. The semiconductor laser as claimed in claim 4 wherein the mesa has a groove in the center of the mesa having a cross-section in a symmetrical or asymmetrical pattern.

8. The semiconductor laser as claimed in claim 7 wherein said first and second confinement layers further comprise an insulating region formed around the periphery of said recess.

9. The semiconductor laser as claimed in claim 7 wherein the pattern is selected from the group consisting of: circular, isosceles triangle, square, regular hexagon, octagon or asymmetric polygon formed by arc segments.

10. A semiconductor laser as claimed in any of claims 1-9 further comprising a first electrode formed on the coherently coupled light emitting cells.

11. The semiconductor laser as claimed in claim 10 wherein the first electrode is separately or integrally disposed.

12. A method of fabricating a semiconductor laser, comprising:

providing a substrate;

forming a stacked structure of a plurality of semiconductor materials on the substrate;

the laminated structure comprises an active layer and an Al X Ga 1-X As layer formed on and/or under the active layer, wherein X is in the range of 0.95-0.99;

locally converting the Al x Ga 1-x As layer into an electrical insulation property to form a current confinement layer, wherein the current confinement layer defines N adjacent sub-light-emitting regions in the active layer, the N adjacent sub-light-emitting regions form a coherent coupling light-emitting unit, and N is an integer greater than or equal to 3.

13. A method of fabricating a semiconductor laser As claimed in claim 12 wherein the step of locally transforming the layer of Al x Ga 1-x As to electrically insulating properties comprises:

etching the laminated structure to form a mesa structure on the substrate;

oxidizing the Al x Ga 1-x As layer, and insulating the periphery of the Al x Ga 1-x As layer exposed by the mesa structure to define the coherent coupling light-emitting unit in the mesa structure.

14. The method of claim 13 wherein the mesa is formed by joining N arcs end to end, N being an integer greater than or equal to 3.

15. A method of fabricating a semiconductor laser as claimed in claim 13 wherein a trench structure is etched into the center of the mesa structure.

16. The method of fabricating a semiconductor laser As claimed in claim 15, oxidizing the Alx Ga 1-xas layer while insulating exposed portions of the Al x Ga 1-xas layer of the trench structure.

17. A method of fabricating a semiconductor laser As claimed in claim 12 wherein the step of locally transforming the layer of Al x Ga 1-x As to electrically insulating properties comprises:

and carrying out ion implantation on the substrate comprising the laminated structure, so that the position corresponding to the Al x Ga 1-x As layer is converted into an insulating layer.

18. A method of fabricating a semiconductor laser as claimed in claim 12 wherein the layered structure further comprises: first and second distributed Bragg reflectors, first and second cladding layers are formed on the substrate.

19. A method of fabricating a semiconductor laser as claimed in claim 12 wherein the layered structure further comprises a buffer layer.

20. A method of fabricating a semiconductor laser as claimed in claims 12-19 forming a first electrode on the second distributed bragg reflector and a second electrode on the substrate.

21. A method of fabricating a semiconductor laser as claimed in claim 20 wherein the first electrode is formed in a discrete or continuous form.

22. An electronic device comprising the semiconductor laser of any one of claims 1-21.

23. The electronic device of claim 22, being a cell phone, a sensor, a lidar, an optical communication module, or a laser printer.

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