Semiconductor laser device, manufacturing method and application thereof

Abstract

The present disclosure provides a semiconductor laser and a method for manufacturing the same. The laser comprises: a substrate; a semiconductor structure formed on the substrate, comprising 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 below the active layer. The confinement layer defines N adjacent sub-light-emitting regions within the active layer, and the N adjacent sub-light-emitting regions form a coherently coupled light-emitting unit, where N is an integer greater than or equal to 3. The present disclosure helps achieve one of the following effects: resolving uneven current spreading, obtaining coherently coupled output, improving beam quality, and providing highly compact alignment and precise confinement.

Description

Technical Field

[0001] The present disclosure relates to semiconductor lasers, and more particularly, to a vertical cavity surface emitting semiconductor laser, a manufacturing method and applications thereof. Background Art

[0002] Semiconductor lasers, especially vertical cavity surface emitting lasers, are an ideal surface emitting light source with the characteristics of good beam quality, single longitudinal mode, low threshold, and easy two-dimensional integration. They have been increasingly widely used in data transmission, sensing, optical interconnection, virtual reality (VR) / augmented reality (AR), laser printing, optical signal processing and other fields.

[0003] In most fields, such as target shooting, laser ranging, image processing, lidar, and sensing, high beam quality requirements are placed on vertical cavity surface emitting lasers (VCSELs). Existing VCSELs achieve coherently coupled output by forming a coherent array. Coherently coupled VCSEL arrays have the potential to produce near-diffraction-limited beams. The coherent superposition of light-emitting units in the array concentrates energy at the axial center, resulting in an axial beam with a narrow far-field divergence angle and a uniform near-field distribution. The larger the array, the better the beam quality, and this has become a hot topic of research.

[0004] To achieve coherently coupled output from VCSEL arrays, structures such as photonic crystals, built-in anti-waveguides, phase adjustment layers, and metal grid electrodes have been designed. To achieve coherently coupled output, the array requires a relatively small spacing between the light-emitting units to ensure coherent coupling of the light emitted from each unit. However, to achieve current limiting between the light-emitting units, a certain spacing must be maintained between the units, which requires a compromise. Therefore, the unit density in current VCSEL coherent arrays cannot be further increased, and the array output power cannot be further improved, nor can the array's beam quality and threshold current characteristics be further enhanced. To address these technical issues, the present invention provides a densely packed VCSEL array that, compared to existing technologies, further improves density and achieves high-power output in a coherent mode.

[0005] In response to the above-mentioned technical problems, the present disclosure utilizes the physical properties of carrier injection in semiconductor lasers and solves the problems of uneven current expansion and incoherent sub-light-emitting areas through a current limiting method with a specific structure. It can obtain coherent coupled output, greatly improve the beam quality of the semiconductor laser, solve the technical problems of uneven current expansion, incoherent light-emitting points, and unstable high-power output, obtain coherent coupled output, achieve highly compact arrangement and precise limitation, and has broad application prospects. Summary of the Invention

[0006] A brief overview of the present disclosure will be provided below to provide a basic understanding of certain aspects of the present disclosure. It should be understood that this overview is not an exhaustive overview of the present disclosure. It is not intended to identify key or important portions of the present disclosure, nor is it intended to limit the scope of the present disclosure. Its purpose is simply to present certain concepts in a simplified form as a prelude to a more detailed description that will be discussed later.

[0007] According to another aspect of the present disclosure, there is provided a semiconductor laser comprising:

[0008] A substrate; a semiconductor structure formed on the substrate, comprising 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 below 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 coherently coupled light-emitting unit, where N is an integer greater than or equal to 3.

[0009] Furthermore, the coherently coupled light-emitting unit is a pattern formed by N arc segments connected end to end when viewed from above.

[0010] Furthermore, the first and / or second current limiting layer is formed by ion implantation.

[0011] Furthermore, a mesa structure is formed on the semiconductor structure, wherein the mesa structure exposes side surfaces of the first and / or second confinement layers, and the first and / or second confinement layers are formed by lateral oxidation.

[0012] Furthermore, in the pattern formed by connecting N arc segments, the distance between the center of the pattern and the edge of the pattern is 3-10 microns.

[0013] Furthermore, the N arc segments are 3-8 arc segments.

[0014] Furthermore, the center of the mesa structure has a groove with a symmetrical or asymmetrical cross-section.

[0015] Furthermore, the first and second restriction layers further include an insulating region formed around the groove.

[0016] Furthermore, the graphic is selected from: a circle, an isosceles triangle, a square, a regular hexagon, an octagon formed by arc segments, or an asymmetric polygon.

[0017] Furthermore, it also includes a first electrode formed on the coherently coupled light-emitting unit.

[0018] Furthermore, the first electrode is provided separately or integrally.

[0019] According to another aspect of the present disclosure, a method for fabricating a semiconductor laser is provided, comprising: providing a substrate; forming a stacked structure composed of multiple semiconductor materials on the substrate; the stacked structure comprising an active layer and an AlxGa1-xAs layer formed above and / or below the active layer, wherein x is in the range of 0.95-0.99; and partially converting the AlxGa1-xAs layer to an electrically insulating property to form a current confinement layer, wherein the current confinement layer defines N adjacent sub-light-emitting regions in the active layer, wherein the N adjacent sub-light-emitting regions form a coherently coupled light-emitting unit, where N is an integer greater than or equal to 3.

[0020] Furthermore, the step of partially converting the AlxGa1-xAs layer into an electrical insulating property includes: etching the stacked structure to form a mesa structure on the substrate; oxidizing the AlxGa1-xAs layer to insulate the periphery of the AlxGa1-xAs layer exposed by the mesa structure to define the coherently coupled light-emitting unit in the mesa structure.

[0021] Furthermore, the mesa structure is a mesa structure formed by connecting N arcs end to end, where N is an integer greater than or equal to 3.

[0022] Furthermore, a groove structure is formed by etching at the center of the mesa structure.

[0023] Furthermore, when the AlxGa1-xAs layer is oxidized, the portion of the AlxGa1-xAs layer exposed by the trench structure is insulated simultaneously.

[0024] Furthermore, the step of partially transforming the AlxGa1-xAs layer into an electrical insulating property includes: performing ion implantation on the substrate including the stacked structure to transform the corresponding position of the AlxGa1-xAs layer into an insulating layer.

[0025] Furthermore, the stacked structure further comprises: forming first and second distributed Bragg reflectors, and first and second cladding layers on the substrate.

[0026] Furthermore, the stacked structure further includes a buffer layer.

[0027] Furthermore, a first electrode is formed on the second distributed Bragg reflector, and a second electrode is formed on the substrate.

[0028] Furthermore, the first electrode is formed in a discrete or continuous form.

[0029] According to yet another aspect of the present disclosure, an electronic device is provided, comprising the aforementioned semiconductor laser.

[0030] Furthermore, the electronic device is a mobile phone, sensor, lidar, optical communication module, or laser printer. The solution of the present disclosure can help achieve at least one of the following effects: solving the problems of uneven current expansion and the inability of each sub-light-emitting region to coherently couple, obtaining coherently coupled output, significantly improving the beam quality of the semiconductor laser, achieving uniform current expansion, obtaining coherently coupled output, and achieving highly dense arrangement and precise definition. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The following description of the present disclosure will provide a more comprehensive understanding of the above and other objects, features, and advantages of the present disclosure with reference to the accompanying drawings. The accompanying drawings are intended only to illustrate the principles of the present disclosure. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale.

[0032] Figure 1 The schematic diagram of laser spot distribution when the current is I1 and I2 is shown, where I1 <I2;

[0033] Figure 2 The calculated near-field and far-field patterns of the laser parallel to the junction plane are shown (from a to e, the operating current gradually increases);

[0034] Figure 3-4 A schematic diagram showing the structure of a semiconductor laser according to a first embodiment;

[0035] Figure 5 A flow chart showing a method for manufacturing a semiconductor laser structure according to a second embodiment;

[0036] Figure 6-8 A schematic diagram showing the structure of a semiconductor laser according to a third embodiment;

[0037] Figure 9 A flowchart of a method for manufacturing a semiconductor laser structure according to a fourth embodiment is shown. DETAILED DESCRIPTION

[0038] Exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings. For the sake of clarity and conciseness, not all features of implementing the present disclosure are described in this specification. However, it should be understood that many decisions specific to the present disclosure may be made in developing any such implementation to achieve the developer's specific goals, and these decisions may vary from one disclosure to another.

[0039] It should also be noted here that in order to avoid obscuring the content of the present disclosure due to unnecessary details, only the device structure closely related to the solution according to the content of the present disclosure is shown in the drawings, while other details that are not closely related to the content of the present disclosure are omitted.

[0040] It should be understood that the present disclosure is not limited to the described embodiments due to the following description with reference to the accompanying drawings. Herein, where feasible, features between different embodiments may be replaced or borrowed, and one or more features may be omitted in one embodiment.

[0041] Usually, in the plane direction parallel to the semiconductor pn junction, since the semiconductor material is the same, there is no change in the refractive index in the plane parallel to the pn junction, so the mode of the semiconductor laser laser light cannot be well restricted.

[0042] Taking GaAs-based lasers as an example, when a semiconductor laser is operating, as current is injected, photons are generated in the active layer, resulting in the material having gain and loss. The refractive index of the material needs to be expressed as a complex number, where the change in the imaginary part is caused by gain and loss, and plays a major role in controlling the lasing light mode. Under the condition of unlimited current, gain and loss can be converted into each other. Laser gain, that is, the generation of stimulated emission photons (generated by carrier recombination in the active layer), will inevitably lead to a decrease in carrier concentration. When it drops below the threshold carrier concentration, stimulated emission photons stop generating. However, the nearby areas that did not reach the threshold carrier concentration reach the lasing threshold as the current increases. Due to mode competition, stimulated photons begin to be emitted here, thus forming spatial hole burning. Spatial hole burning causes periodic changes in the imaginary part of the refractive index, and the width of the change is the carrier diffusion length L. It conforms to the following formulas (1) and (2), which is about 3-5 microns for GaAs-based materials.

[0043]

[0044]

[0045] where D is the diffusion coefficient and τ is the carrier lifetime.

[0046] Due to the periodic change of the imaginary part of the refractive index, a periodic self-focusing effect is generated. Therefore, the light is arranged in an array on the plane parallel to the pn junction. The overall laser is the overall effect of multiple laser light spots. The schematic diagram of the light spot emission is shown in Figure 1 As the current injection increases, each lasing light spot moves. Since the position of the light spot is constantly changing, the light emitted by adjacent lasing light spots cannot form coherent coupling, and thus the adjacent lasing light spots cannot form a coherently coupled light-emitting unit.

[0047] A careful study of the laser light spot reveals that the light spot conforms to formula (3),

[0048]

[0049] Where: E(y,z) is the field intensity of the outgoing light, y is the direction parallel to the junction, and z is the outgoing direction. The expression of the field intensity is shown in formula (4):

[0050]

[0051] Substituting formula (4) into formula (3),

[0052] Since the propagation direction is the z direction, the light intensity in the z direction fluctuates and is a sinusoidal wave, so we can set: v(y,z)=A(y)e δz After a series of calculations, the electric field equation parallel to the junction direction is obtained as shown in formula (5).

[0053]

[0054] The near-field and far-field patterns are calculated according to formula (5) and then according to formulas (6) and (7).

[0055] Near-field graphics

[0056] I(y)∝|v(y)| 2 Formula (6)

[0057] Far-field graphics

[0058] I(θ)∝cos 2 θ|F(θ) 2 | Formula (7)

[0059] in,

[0060] According to the above analysis, the near-field and far-field patterns of the light spot of the GaAs-based laser parallel to the plane of the pn junction can be obtained by calculation, such as Figure 2 As shown in the figure, the left part is the luminous intensity of the near-field pattern, the right part is the divergence angle of the far-field pattern, y is the distance from the center of the pn junction, and the operating current gradually increases from (a) to (e). It can be seen that when the current is small, the near-field pattern is two separate lasing light spots. Because the light spots are far apart, no coherent coupling occurs, so the far-field pattern has a larger divergence angle and appears as two independent light spots (corresponding to Figure 2In (a), as the working current increases, the number of laser light spots increases, the distance between the light spots gradually approaches, and the change from weak coherent coupling to strong coherent coupling begins. The divergence angle of the far-field pattern gradually decreases, and gradually changes to independent light spots after coherent coupling (corresponding to Figure 2 (e)).

[0061] Based on these laser characteristics, the inventors proposed a coherently coupled, close-packed vertical-cavity surface-emitting semiconductor laser (VCSEL) design. By implementing current confinement above or below the active layer, the confinement layer in the device structure becomes a permanent, stable insulating layer that remains unchanged by current flow. The uninsulated portion remains unconfined, thus forming a current path.

[0062] Based on the previous analysis of spatial hole burning and carrier diffusion characteristics, the current of each sub-light-emitting area is first limited by the current limiting layer, so as to control the light spots of each sub-light-emitting area inside the VCSEL laser from moving. The current limiting pattern is not a conventional circle or diamond. By calculating the number of light spots in the sub-light-emitting area and the distance between the light spots in the sub-light-emitting area, a current limiting scheme is designed so that the light spots in the sub-light-emitting area are normally stimulated to emit photons when the current I1 is injected. When the carrier concentration decreases, no current injection can be formed near it. If the carrier concentration is always low, it cannot be excited and luminesced. The original light spot is supplemented by current injection to make the carrier concentration reach the threshold again, and continues to emit light at the original light spot position at I2, thereby ensuring that the light spots in the light-emitting area do not move, where I1 <I2。

[0063] Secondly, the distance between the light spots in the sub-luminescent areas is controlled by current limitation to achieve their strong coupling and weak coupling.

[0064] Such current confinement can be achieved by ion implantation or lateral oxidation of the current confinement layer above or below the active layer.

[0065] First embodiment

[0066] Reference Figure 3-Figure 4 A semiconductor laser and a method for manufacturing the same according to a first embodiment will be described.

[0067] like Figure 3-4 As shown, in the first embodiment, the semiconductor laser is a vertical cavity surface emitting semiconductor laser, which includes a substrate 100. The material of the substrate 100 can be selected according to actual needs, and the present disclosure does not limit the specific material of the substrate 100. Exemplarily, the material of the substrate 100 can be a Group III-V material or a Group IV material, such as a gallium arsenide (GaAs) substrate, indium phosphide (InP), a silicon (Si) substrate, or a silicon carbide (SiC) substrate. Typically, the gallium arsenide (GaAs) layer can be an n-type gallium arsenide substrate.

[0068] Optionally, a buffer layer 101 is provided on the substrate 100. The thickness and corresponding doping concentration are designed according to the requirements of the specific device to achieve a reasonable resistance value. For example, the buffer layer can be deposited on an n-type gallium arsenide substrate. The thickness of the buffer layer is 100-300 nanometers and the doping concentration is 1×10 17 cm -3 -7×10 18 cm -3 In between, the buffer layer can be doped with the same type of doping as the substrate.

[0069] A first distributed Bragg reflector 102 is provided on the buffer layer 101. Exemplarily, the first distributed Bragg reflector 102 may be formed by alternating multiple first sublayers and multiple second sublayers. Exemplarily, when the substrate 100 is n-type doped GaAs, the first distributed Bragg reflector 102 is n-type doped. Furthermore, the first sublayer of the first distributed Bragg reflector 102 is composed of n-type AlxGa1-xAs, and the second sublayer is composed of AlyGa1-yAs, where x ranges from 0 to 0.5 and y ranges from 0.5 to 1. Depending on the material type and composition, the number of first and second sublayers may be 10-40, respectively, and typically 20-30.

[0070] A first cladding layer 103 is provided on the first distributed Bragg reflector 102. For GaAs materials, the first cladding layer may be Al x Ga 1-x As / Al y Ga 1-y As material, wherein x ranges from 0 to 0.5, y ranges from 0.5 to 1, and the first cladding layer is 1×10 17 cm -3 to 5×10 18 cm -3 The doping level of the n-type material layer.

[0071] Next, the active layer 104 formed on the first cladding layer 103 depends on the desired output wavelength and material type of the laser structure. For GaAs-based materials, the active layer can be exemplarily composed of 1-9 pairs of AlGaAs / GaAs quantum well or quantum dot structures, wherein the Al component can be 0.1-0.9; for InP-based materials, the active layer can be exemplarily composed of 1-9 pairs of InGaAsP / InP quantum well or quantum dot structures.

[0072] A second cladding layer 105 is further formed on the active layer 104. The second cladding layer 105 is similar to the first cladding layer 103 and can be made of a material composed of AlxGa1-xAs / AlyGa1-yAs, wherein x ranges from 0 to 0.5, y ranges from 0.5 to 1, and the second cladding layer is 1×10 17 cm -3 to 5×10 18 cm -3 The doping level of the p-type material layer.

[0073] 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.

[0074] Furthermore, the first current limiting layer 106 is formed on the second cladding layer. Typically, the first current limiting layer 106 is formed by converting a portion of the material into an insulating layer through ion implantation to achieve current limiting.

[0075] More preferably, the VCSEL injection current can be limited by etching to form mesas to expose the side surfaces of the high-aluminum AlxGa1-xAs. Lateral oxidation of the high-aluminum AlxGa1-xAs can then be performed to form an oxide confinement layer, where x ranges from 0.95 to 0.99. The lateral oxidation oxidizes the outer periphery of the high-aluminum AlxGa1-xAs into insulating aluminum oxide, allowing the unoxidized interior to serve as a current path for carriers. The oxidized interior also serves as an optical waveguide due to a change in refractive index, and the unoxidized interior serves as a light exit hole for the VCSEL. The diameter of the sub-light-emitting region formed by each light exit hole can be 2-8 microns. Specifically, the first current confinement layer 106 provides current and optical confinement through changes in conductivity and refractive index, thereby forming a smaller first conductive region above the active layer 104. In which, the current limiting layer is on the periphery of the first conductive area, thereby defining N sub-light-emitting areas in the first conductive area, and the N adjacent sub-light-emitting areas define a coherently coupled light-emitting unit. Exemplarily, the outer contour of the coherently coupled light-emitting unit formed by the sub-light-emitting areas is a figure composed of N adjacent arc segments when viewed from a top view, and the average aperture is 2-8um.

[0076] The number of N can be set to an integer greater than or equal to 3 as needed. For example, the coherently coupled light-emitting unit is configured such that the sub-light-emitting region is three arc-shaped sub-light-emitting regions connected end to end when viewed from above. The current limiting layer is used to limit current injection so that the region where the current flows into conforms to the carrier diffusion shape, and can clamp and fix the position of the light-emitting point so that each light-emitting point in the vertical cavity surface emitting laser structure is simultaneously injected with current to ensure the same phase, thereby achieving the purpose of coherent output, and realizing strong coherent coupling between multiple adjacent sub-light-emitting regions to form a coherently coupled light-emitting unit, thereby stabilizing the output mode and achieving stable single transverse mode output, which greatly improves the quality and power of the output beam.

[0077] Then, a second distributed Bragg reflector 107 is further formed on the first current confining layer 106. Correspondingly, the second distributed Bragg reflector 107 is similarly formed by alternating multiple third sublayers and multiple fourth sublayers. Exemplarily, when the substrate 100 is n-type doped GaAs, the second distributed Bragg reflector 107 is p-type doped. Furthermore, the third sublayer of the second distributed Bragg reflector 107 is composed of p-type AlxGa1-xAs, and the fourth sublayer is composed of AlyGa1-yAs, where x ranges from 0 to 0.5 and y ranges from 0.5 to 1. The number of the third and fourth sublayers can be 10-40, respectively, and the number of the first and second sublayers can typically be 20-30.

[0078] It is further understood that a second current confining layer 108 may be formed below the first cladding layer 103. The second current confining layer 108 is disposed corresponding to the first current confining layer 106. It is also understood that the second current confining layer may be formed at any position between the first distributed Bragg reflector and the active layer. Similarly, the first current confining layer may be formed at any position between the active layer and the second distributed Bragg reflector.

[0079] It can be further understood that the first current limiting layer and the second current limiting layer can be formed separately, or the first current limiting layer and the second current limiting layer can be respectively formed by the outermost layers of the second distributed Bragg reflector and the first distributed Bragg reflector closest to the active layer.

[0080] Furthermore, a first electrode 109 is formed on the second distributed Bragg reflector. The first electrode may partially contact each of the light-emitting regions, or the first electrode may surround the light-emitting units. A second electrode 110 is formed on the back surface of the substrate 100. Similarly, the second electrode may be integrally provided on the back surface or provided corresponding to each light-emitting unit. The electrode material is selected from one or more of Ti, Au, Ge, Ni, Pt, Pd, and alloys thereof.

[0081] Second embodiment

[0082] Now refer to Figure 5 A method for manufacturing the semiconductor laser of the first embodiment will be described in detail.

[0083] Step 1: Provide a substrate 100.

[0084] Step 2: Form a buffer layer on the substrate 100. The buffer layer can be formed by an epitaxial deposition process of metal organic chemical vapor deposition (MOCVD) or 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 In between, the buffer layer can be doped with the same type of doping as the substrate.

[0085] Step 3: Multiple first sub-layers and multiple second sub-layers are alternately epitaxially formed on the buffer layer 101 to form the first distributed Bragg reflector 102. The number of the first sub-layers and the second sub-layers can be 10-40 respectively, and typically the number of the first sub-layers and the second sub-layers can be 20-30.

[0086] Step 4: forming a first cladding layer 103 on the first distributed Bragg reflector 102. The doping concentration of the first cladding layer 103 may be 1×10 17 cm -3 to 5×10 18 cm -3 The doping level of the n-type material layer.

[0087] Step 5: Optionally, an AlxGa1-xAs layer is formed between the first distributed Bragg reflector 102 and the first cladding layer 103, where X is in the range of 0.95-0.99.

[0088] Step 6: An active layer 104 is formed on the AlxGa1-xAs layer. The active layer 104 can be selectively formed into a quantum well or quantum dot structure consisting of 1-9 pairs of AlGaAs / GaAs, wherein the Al component can be 0.1-0.9. For InP-based materials, the active layer can illustratively be formed into a quantum well or quantum dot structure consisting of 1-9 pairs of InGaAsP / InP.

[0089] Step 7: forming a second cladding layer 105 on the active layer 104 . The growth process of the second cladding layer 105 is similar to that of the first cladding layer 103 , but the doping type of the second cladding layer 105 is opposite to that of the first cladding layer 103 .

[0090] Step 8: Form an AlxGa1-xAs layer on the second cladding layer 105, wherein the range of X is 0.95-0.99.

[0091] Step 9: Multiple third sub-layers and multiple fourth sub-layers are alternately epitaxially formed on the AlxGa1-xAs layer to form the second distributed Bragg reflector 107. The number of the third sub-layers and the fourth sub-layers can be 10-40, respectively. Typically, the number of the first sub-layers and the second sub-layers can be 20-30, and their doping types are opposite to those of the first distributed Bragg reflector.

[0092] Step 10: Etching the stacked structure to form a mesa structure formed by connecting N circular arcs. Exemplarily, N is 3. The mesa structure exposes the side of the AlxGa1-xAs layer, and then the AlxGa1-xAs layer is laterally oxidized to form a first and / or second oxidized current limiting layer that suppresses current. The oxidized current limiting layer surrounds the active layer to define adjacent sub-light-emitting regions. The sub-light-emitting regions are then combined to form a coherently coupled light-emitting unit, achieving VCSEL density while significantly improving output power and beam quality.

[0093] Optionally, if the oxidation current limiting layer is formed by ion implantation instead of lateral oxidation, step 10 does not need to form a mesa structure by etching. Instead, the ion implantation dose and implantation energy are controlled directly so that the electrical properties of the area corresponding to the limiting layer are transformed into insulation through ion implantation to form an ion implanted current limiting layer to achieve current injection limitation. By controlling the position of the ion implantation, the final ion implanted limiting layer and the oxidation current limiting layer have the same shape as the area surrounding the active layer, and thus the sub-light-emitting area defined is also the same shape.

[0094] Step 11: forming a metal layer on the second distributed Bragg reflector 107 and performing high-temperature annealing to form a first electrode 109 . The first electrode can be formed by sputtering or other processes.

[0095] Step 12: forming a second electrode 110 on the back side of the substrate 100. The substrate is thinned, and then a metal layer is formed thereon, and annealed at a high temperature to achieve good ohmic contact, thereby forming the second electrode 110.

[0096] It is understood that the second oxidation current limiting layer 108 is provided corresponding to the first oxidation current limiting layer 106. It is also understood that the second oxidation current limiting layer can be formed at any position between the first distributed Bragg reflector and the active layer, and similarly, the first oxidation current limiting layer can be formed at any position between the active layer and the second distributed Bragg reflector.

[0097] Third embodiment

[0098] like Figure 6 As shown, the only difference from the first embodiment is that the center of the light-emitting unit has a groove, which is symmetrical or asymmetrical when viewed from above. For example, the groove can be a circle, an equilateral triangle, a square, or a symmetrical shape with the same or opposite arc direction as the outer arc direction of the light-emitting unit. The aperture can range from 1 to 20 microns.

[0099] The outer contours of the cross sections of the N sub-light emitting regions are an oxidation current limiting layer formed by N circular arcs connected end to end, and the outer contour of the groove is also an oxidation current limiting layer formed by a closed curve.

[0100] The number of N can be set to be greater than or equal to three as needed. For example, the light-emitting unit can be a light-emitting unit composed of three to eight arcs when viewed from above, such as Figure 7-8 The distance from the center of the groove to the light-emitting unit is in the range of 3-10 microns.

[0101] Fourth Implementation Plan

[0102] Reference Figure 9 A semiconductor laser and a method of manufacturing the same according to a fourth embodiment will be described.

[0103] The only difference from the second embodiment is that step 10 is replaced by step 10':

[0104] Step 10': Etching the stacked structure to form a mesa structure of a light-emitting unit formed by connecting N circular arcs, and forming a symmetrically patterned trench structure at the center of the mesa structure. The mesa structure and the trench structure expose the side surfaces of the AlxGa1-xAs layer. The AlxGa1-xAs layer is then laterally oxidized through the outer side of the mesa structure and the trench structure to form a first and / or second oxidized current limiting layer that suppresses current. The oxidized current limiting layer surrounds the active layer and the trench to define adjacent sub-light-emitting regions. The sub-light-emitting regions are then combined to form a coherently coupled light-emitting unit, thereby achieving density while greatly improving output power and beam quality.

[0105] Fifth Implementation Plan

[0106] An electronic device, which may be a data transmission device, a sensor, an optical interconnect module, an optical communication module, a virtual reality (VR) / augmented reality (AR) device, a laser printer, or a mobile phone. The electronic device may include any of the semiconductor lasers in the above embodiments.

[0107] The present disclosure is described above in conjunction with specific embodiments. However, it should be clear to those skilled in the art that these descriptions are illustrative only and are not intended to limit the scope of protection of the present disclosure. Those skilled in the art may make various variations and modifications to the present disclosure based on the spirit and principles of the present disclosure, and such variations and modifications are also within the scope of the present disclosure.

Claims

1. A semiconductor laser comprising: a substrate; A semiconductor structure formed on a substrate includes first and second distributed Bragg reflectors, first and second cladding layers, and an active layer; and a first current limiting layer formed on the active layer and / or a second current limiting layer formed under the active layer; The current limiting layer defines N adjacent sub-light-emitting regions in the active layer, and the N adjacent sub-light-emitting regions form a coherently coupled light-emitting unit, where N is an integer greater than or equal to 3; The current limiting layer is electrically insulating and forms a first conductive region of a smaller range above and / or below the active layer. The current limiting layer is on the periphery of the first conductive region, thereby defining the N adjacent sub-light-emitting regions in the first conductive region. 2 . The semiconductor laser according to claim 1 , wherein the coherently coupled light-emitting unit is a pattern formed by connecting N arc segments end to end when viewed from above. 3 . The semiconductor laser according to claim 1 , wherein the first and / or second current confinement layers are formed by ion implantation. 4 . The semiconductor laser according to claim 1 , wherein a mesa structure is formed on the semiconductor structure, the mesa structure exposing side surfaces of the first and / or second current confinement layer, and the first and / or second current confinement layer is formed by lateral oxidation.

5. The semiconductor laser as claimed in claim 2, wherein in the pattern formed by connecting N arc segments end to end, the distance between the center of the pattern and the edge of the pattern is 3-10 microns. The semiconductor laser as claimed in claim 2 , wherein the N arc segments are 3-8 arc segments.

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

8. The semiconductor laser as claimed in claim 7, wherein the first and second current confinement layers further comprise an insulating region formed around the groove.

9. The semiconductor laser as claimed in claim 7, wherein the shape is selected from the group consisting of a circle, an isosceles triangle, a square, a regular hexagon, an octagon formed by arc segments, and an asymmetric polygon. 10 . The semiconductor laser according to claim 1 , further comprising a first electrode formed on the coherently coupled light emitting unit.

11. The semiconductor laser according to claim 10, wherein the first electrode is provided separately or integrally.

12. A method for preparing a semiconductor laser, comprising: providing a substrate; forming a stacked structure of multiple semiconductor materials on the substrate; The stacked structure comprises an active layer and an AlxGa1-xAs layer formed on and / or under the active layer, wherein the range of x is 0.95-0.99; Part of the AlxGa1-xAs layer is converted into an electrical insulating property to form a current limiting layer, wherein the current limiting layer defines N adjacent sub-light-emitting regions in the active layer, and the N adjacent sub-light-emitting regions form a coherently coupled light-emitting unit, where N is an integer greater than or equal to 3; The current limiting layer forms a first conductive region of a smaller range above and / or below the active layer, and the current limiting layer is at the periphery of the first conductive region, thereby defining the N adjacent sub-light-emitting regions in the first conductive region.

13. The method for manufacturing a semiconductor laser according to claim 12, wherein the step of partially converting the AlxGa1-xAs layer into an electrical insulating property comprises: etching the stacked structure to form a mesa structure on the substrate; The AlxGa1-xAs layer is oxidized, and the periphery of the AlxGa1-xAs layer exposed by the mesa structure is insulated to define the coherently coupled light emitting unit in the mesa structure. 14 . The method for manufacturing a semiconductor laser according to claim 13 , wherein the mesa structure is a mesa structure formed by connecting N circular arcs end to end, where N is an integer greater than or equal to 3. 15 . The method for manufacturing a semiconductor laser according to claim 13 , wherein a groove structure is formed by etching at the center of the mesa structure. 16 . The method for fabricating a semiconductor laser according to claim 15 , wherein when oxidizing the Al x Ga 1-x As layer, the portion of the Al x Ga 1-x As layer exposed by the trench structure is simultaneously insulated.

17. The method for fabricating a semiconductor laser according to claim 12, wherein the step of partially converting the AlxGa1-xAs layer into an electrically insulating property comprises: Ion implantation is performed on the substrate including the stacked structure, so that the position corresponding to the AlxGa1-xAs layer is converted into an insulating layer.

18. The method for manufacturing a semiconductor laser according to claim 12, wherein the stacked structure further comprises: First and second distributed Bragg reflectors, and first and second cladding layers are formed on the substrate.

19. The method for manufacturing a semiconductor laser according to claim 12, wherein the stacked structure further comprises a buffer layer. 20 . The method for manufacturing a semiconductor laser according to claim 18 , wherein a first electrode is formed on the second distributed Bragg reflector, and a second electrode is formed on the substrate. 21 . The method for manufacturing a semiconductor laser according to claim 20 , wherein the first electrode is formed in a discrete or continuous form.

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

23. The electronic device as claimed in claim 22 is a mobile phone, a sensor, a laser radar, an optical communication module or a laser printer.

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