Surface emitting laser and method for manufacturing the same

Abstract

The embodiment of the present application relates to a surface emitting laser and its preparation method. The surface emitting laser includes a substrate and a resonant cavity structure provided on the substrate; the resonant cavity structure includes a first reflector layer, an active layer, and a second reflector layer sequentially located on the substrate; a photoelectric confinement layer is formed in the second reflector layer, the photoelectric confinement layer is a polygonal ring structure, and the inner ring of the photoelectric confinement layer includes at least three inner angles; and the second reflector layer also includes a non-ion implantation area of ​​an inclined column, the non-ion implantation area of ​​the inclined column does not overlap with at least one of the at least three inner angles of the inner ring of the photoelectric confinement layer; in the second reflector layer, the area outside the non-ion implantation area of ​​the inclined column is an ion implantation area. The present application forms a non-ion implantation area of ​​an inclined column in the second reflector layer; so that the current concentration of the corresponding photoelectric confinement layer is destroyed, thereby improving the reverse breakdown voltage capability of the device.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor laser technology, and in particular to surface emitting lasers and methods for preparing the same. Background Art

[0002] VCSEL is a new type of semiconductor laser, which is characterized by small size, low threshold current, and easy two-dimensional integration. It is widely used in optical communications, optical interconnection and other fields.

[0003] However, the reverse breakdown voltage of VCSEL devices is still a technical indicator that needs to be improved. Improving the reverse breakdown voltage can not only enhance the reliability of the device but also expand its application range.

[0004] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of the present invention is to provide a surface emitting laser and a preparation method thereof, aiming to solve the above technical problems in the prior art.

[0006] Based on this, it is necessary to provide a surface emitting laser and a preparation method thereof to address the above technical problems.

[0007] In a first aspect, the present application provides a surface emitting laser, comprising a substrate and a resonant cavity structure provided on the substrate;

[0008] The resonant cavity structure includes a first reflector layer, an active layer, and a second reflector layer sequentially located on the substrate;

[0009] A photoelectric confinement layer is formed in the second reflector layer, the photoelectric confinement layer is a polygonal ring structure, and the inner ring of the photoelectric confinement layer includes at least three inner corners; and

[0010] The second reflector layer further includes a non-ion implanted region of an inclined column, wherein the non-ion implanted region of the inclined column does not overlap with at least one of the at least three inner angles of the inner ring of the photoelectric confinement layer;

[0011] In the second reflector layer, the area outside the non-ion implantation area of ​​the inclined columns is the ion implantation area.

[0012] In one embodiment, the shape of the inner ring of the photovoltaic confinement layer includes an irregular polygon or a regular polygon;

[0013] The region where the non-ion implantation region of the inclined column intersects with the photoelectric confinement layer at least does not include an inner corner of an inner ring of the photoelectric confinement layer.

[0014] In one embodiment, the second reflector layer further includes a C-shaped contact metal pad, and the opening of the C-shaped contact metal pad faces the first inner angle, which is an inner angle of the inner ring of the photoelectric confinement layer in the area where the non-ion implantation area of ​​the inclined column intersects the photoelectric confinement layer.

[0015] In one embodiment, the shape of the non-ion implanted region of the inclined column away from the active layer on the surface of the second reflector layer does not include any inner corner of the inner ring of the photovoltaic confinement layer in the projection area of ​​the photovoltaic confinement layer.

[0016] In one embodiment, the shape of the inner ring of the photoelectric limiting layer is a regular polygon, and the shape of the non-ion implanted region of the inclined column away from the active layer on the surface of the second reflector layer is projected on the photoelectric limiting layer as an inscribed circle of the inner ring of the photoelectric limiting layer.

[0017] In one embodiment, the tilt angle of the non-ion implantation region of the inclined column relative to the vertical direction of the upper surface of the second reflector layer is 2°-7°.

[0018] In a second aspect, the present application further provides a method for preparing a surface emitting laser, comprising:

[0019] Providing an epitaxial layer; wherein the epitaxial layer includes a substrate and a first reflector layer, an active region, and a second reflector layer sequentially arranged on the substrate;

[0020] performing mesa etching on the epitaxial layer to obtain a plurality of grooves, wherein the grooves expose a portion of the surface of the first reflector layer;

[0021] Performing a wet oxidation process on the epitaxial layer through the trench to form a photoelectric confinement layer in the second reflector layer; wherein the photoelectric confinement layer is a polygonal ring structure, and the inner ring of the photoelectric confinement layer includes at least three inner corners;

[0022] Applying a mask pattern on the surface of the epitaxial layer and performing an ion implantation process on the epitaxial layer through the mask pattern to form a non-ion implantation region of the inclined column in the second reflector layer;

[0023] Wherein, the area outside the non-ion implantation area of ​​the inclined column is the ion implantation area.

[0024] In one embodiment, the groove is an irregular polygon or a regular polygon connected end to end.

[0025] In one embodiment, before mesa etching the epitaxial layer, the method further comprises: forming a C-shaped contact metal pad on the second reflector layer.

[0026] In one embodiment, in the step of performing an ion implantation process on the epitaxial layer through the mask pattern, the ion implantation angle is inclined by 2°-7° relative to a vertical direction of an upper surface of the second reflector layer.

[0027] The present invention has at least the following beneficial effects:

[0028] The surface emitting laser provided by the present invention forms a non-ion implantation region of an inclined column in the second reflector layer, thereby destroying the current concentration of the corresponding photoelectric confinement layer and improving the reverse breakdown voltage capability of the device.

[0029] In a third aspect, the present application provides a VCSEL chip comprising at least one laser array; the laser array comprises a plurality of surface-emitting lasers as described above; the laser array is a regularly arranged array, or a randomly arranged array, or an array having multiple addressable sub-arrays.

[0030] In a fourth aspect, the present application provides a light source for a lidar system, comprising at least one surface emitting laser as described above or at least one VCSEL chip as described above.

[0031] In a fifth aspect, the present application provides a laser radar system, comprising a transmitting component and a receiving component, wherein the transmitting component adopts the above-mentioned light source for the laser radar system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of a surface emitting laser in one embodiment of the present application;

[0033] Figure 2 is a schematic top view of a surface emitting laser according to an embodiment of the present application;

[0034] Figure 3 Schematic diagram of the distribution of the non-ion implantation region A1 and the ion implantation region A2 of the surface emitting laser according to one embodiment of the present application on the side of the second reflector layer away from the active layer;

[0035] Figure 4 Schematic diagram of the distribution of the non-ion implantation area A1 and the ion implantation area A2 of the surface emitting laser of one embodiment of the present application on the side of the second reflector layer close to the active layer;

[0036] Figure 5 A schematic diagram of a surface emitting laser according to an embodiment of the present application performing an ion implantation process on the epitaxial layer through the mask pattern;

[0037] Figure 6This is a flow chart of a method for preparing a surface emitting laser in one embodiment of the present application.

[0038] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0040] It should be understood that the terms "first," "second," and the like used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are used solely to distinguish a first element from another element. For example, a first client may be referred to as a second client, and similarly, a second client may be referred to as a first client, without departing from the scope of this application.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, features specified as "first" or "second" may explicitly or implicitly include at least one of such features. "Multiple" means at least two, such as two, three, etc., unless otherwise specifically defined. "Several" means at least one, such as one, two, etc., unless otherwise specifically defined.

[0042] As described in the background technology of this application, a vertical-cavity surface-emitting laser (VCSEL) is a semiconductor laser whose laser beam is emitted perpendicular to the chip surface. It has the advantages of low threshold current, high modulation bandwidth, circular spot, and easy arraying. It is widely used in optical communications, optical interconnection, 3D sensing, consumer electronics and other fields.

[0043] However, existing VCSEL structures still have some issues. In particular, when using oxide confinement (OA) technology, regular or irregular polygons are formed, and current concentrations are likely to occur at the corners of the polygons. These current-concentrated corners are more likely to cause breakdown under forward and reverse bias, especially during reverse bias testing, thus affecting device reliability. This reduces the reliability and service life of VCSEL devices under high-power or long-term operating conditions.

[0044] Based on this, see Figure 1The present application provides a surface-emitting laser (SEL) comprising a substrate St and a resonant cavity structure (not shown) disposed on the substrate St. The resonant cavity structure comprises a first reflector layer 10, an active layer 20, and a second reflector layer 30. A photoelectric confinement layer is formed in the second reflector layer. The photoelectric confinement layer is a polygonal ring structure, and the inner ring of the photoelectric confinement layer includes at least three internal angles. The photoelectric confinement layer is provided with a photoelectric confinement pattern OA for defining the light-emitting area of ​​the SEL. The second reflector layer also comprises a non-ion-implanted region A1 of an inclined column, which does not overlap with at least one of the at least three internal angles of the inner ring of the photoelectric confinement layer. In the second reflector layer, the area outside the non-ion-implanted region of the inclined column is an ion-implanted region A2, i.e., the non-ion-implanted region A1 of the inclined column is surrounded by the ion-implanted region A2. The ion-implanted region A2 is formed by implanting hydrogen or helium ions into the resonant cavity structure through a mask from the second reflector layer 30 toward the substrate at a predetermined tilt angle. The implanted energy can be, for example, 50-100 keV. The ion implantation region A2 is configured as a non-conductive region or a passivation current concentration region. Ion bombardment causes damage to the lattice structure of the region, thereby increasing the resistivity and reducing the current passing through the region, thereby forming the region of the second reflector layer other than the ion implantation region into a non-ion implantation region of an inclined column; thereby destroying the current concentration of the corresponding photoelectric confinement layer and improving the reverse breakdown voltage capability of the device.

[0045] In this specific embodiment, the first reflector layer 10 and the second reflector layer 30 define the resonant cavity structure of the surface-emitting laser of the present application. Specifically, the region between the first reflector layer 10 and the second reflector layer 30 constitutes the resonant cavity. The resonant cavity is used to generate standing waves, which are waves formed by two coherent waves propagating in opposite directions on the same straight line and superimposed on each other. Specifically, when the two waves are in phase, their amplitudes add together, forming antinodes (i.e., crests). When the two waves are in opposite phases, their amplitudes subtract from each other, forming nodes (i.e., troughs). Therefore, the crests and troughs of the standing wave are fixed in position.

[0046] In one embodiment, the first reflector layer 10 may include a periodically stacked DBR structure, that is, a plurality of reflectors with an optical thickness of one-quarter the laser wavelength, and the plurality of reflectors are arranged alternately according to high and low refractive indices. The second reflector layer 30 also includes a periodically stacked DBR structure, that is, a plurality of reflectors with an optical thickness of one-quarter the laser wavelength, and the plurality of reflectors are arranged alternately according to high and low refractive indices. It is understandable that the components, number of stacking periods, etc. of the DBR structure of the first reflector layer 10 and the DBR structure of the second reflector layer 30 may be the same or different, and this is not limited in this embodiment. Among them, the material of the second reflector layer 30 and the first reflector layer 10 may be a dielectric material with electrical insulation, for example, silicon nitride, silicon oxide, aluminum oxide or titanium oxide. The material of the second reflector layer 30 and the first reflector layer 10 may also be a semiconductor material, for example, GaAs and AlGaAs.

[0047] The materials of the substrate St include, but are not limited to, GaAs, InP, Si, etc. The first reflector layer 10 and the second reflector layer 30 may include films with periodically varying refractive indices to achieve efficient reflection or transmission of light within a specific wavelength range. The films with periodically varying refractive indices may be composed of semiconductor materials, dielectric materials, metal-dielectric hybrid materials, etc. For example, the first reflector layer 10 may be an N-type semiconductor layer, and the second reflector layer 30 may be a P-type semiconductor layer. In another example, the first reflector layer 10 may be a P-type semiconductor layer, and the second reflector layer 30 may be an N-type semiconductor layer. Alternatively, the materials of the N-type and P-type semiconductor layers may be, but are not limited to, GaAs, AlGaAs, etc., and are not limited here. As long as the resonant cavity can be defined, they fall within the scope of protection of this embodiment. In this specific embodiment, the substrate St may be made of GaAs material with a thickness between 400 and 600 microns, for example, 500 microns. The first reflector layer 10 may, for example, be composed of 30 to 40 stacked pairs of AlGaAs / GaAs. The second reflective mirror layer 30 may be formed by stacking 20 to 30 pairs of AlGaAs / GaAs.

[0048] The active layer 20 comprises a multi-quantum well structure composed of GaAs / AlGaAs materials, with 3-5 quantum wells. The multi-quantum well structure is used to generate stimulated emission of photons. The emitted photons are continuously reflected in the resonant cavity defined by the first and second reflector layers 10 and 30, where they are continuously enhanced during the reflection process, ultimately emitting laser light at a specific wavelength and with sufficient energy.

[0049] The multi-quantum well structure is where laser gain amplification is generated, and the center position of the multi-quantum well structure can be aligned with the position where the light field is strongest to achieve a greater amplification effect. Furthermore, in the case of multiple multi-quantum well structures, the confinement factors of the multi-quantum well structures in the same section of the light field are within the same preset range, that is, the confinement factors of each multi-quantum well structure are maintained at the same level, so that the contribution of each multi-quantum well structure to luminescence is similar. It can be understood that similar luminescence contributions mean that the injection of current into each multi-quantum well structure is more uniform, which helps to reduce the threshold current of the device, thereby reducing the power consumption of the device and extending its service life. Moreover, when the contribution of each multi-quantum well structure to luminescence is similar, the distribution of carriers in each multi-quantum well structure will be more uniform, which helps to reduce the recombination loss of carriers, thereby improving the overall luminescence efficiency of the device.

[0050] The photoelectric confinement layer is formed in the second reflector layer 30. Specifically, the photoelectric confinement layer is located on the side of the corresponding active layer 20 away from the substrate St to limit the flow of current, so that the current flows only within the luminescent region defined by the photoelectric confinement layer 132, thereby reducing unnecessary energy consumption, thereby reducing the threshold current, and increasing the current density. Moreover, the photoelectric confinement layer can also confine the light field to the luminescent region defined by the photoelectric confinement layer, reducing light scattering and diffraction, thereby optimizing the divergence angle of the device and improving the beam quality. Typically, the photoelectric confinement layer is located at the location with the lowest light field intensity, that is, at the trough of the standing wave, so that it has a smaller confinement factor, which helps to reduce the divergence angle of the device.

[0051] Photoelectric confinement layers can include any of air column-type, oxide-type, ion-implanted, and tunnel junction-type confinement layers. Air column-type confinement layers confine current and light through air columns, hollow structures formed through dry etching techniques. The air columns have a lower refractive index than the surrounding semiconductor material, effectively confining light to the central region. Ion-implanted confinement layers modify the electrical properties of semiconductor materials by injecting ions into them, creating high-resistance regions that restrict current flow and thus indirectly limit the light generation region.

[0052] In one embodiment, the oxidation-restricted photoelectric confinement layer includes an unoxidized region of AlGaAs material with a high Al content and an oxidized region of aluminum oxide material. The oxidized region is arranged outside the unoxidized region, and the unoxidized region forms a light-emitting region for effective current injection. Among them, the semiconductor layer in the unoxidized region of the photoelectric confinement layer can be understood as a photoelectric confinement pattern OA, which is used to define the light-emitting region of the surface emitting laser. When current enters, the current can only flow to the active layer 20 through the photoelectric confinement pattern OA in the photoelectric confinement layer, thereby achieving the limitation of the current injection path and the optical mode field. Furthermore, the AlGaAs layer with a high aluminum content can be converted into aluminum oxide through a selective oxidation process to form a peripheral unoxidized region.

[0053] In one embodiment, the tunnel junction type photoelectric confinement layer includes at least one highly doped N-type structure layer and at least one highly doped P-type structure layer. Specifically, a potential barrier is formed between the highly doped N-type structure layer and the highly doped P-type structure layer, and electrons are allowed to pass through the potential barrier by tunneling, thereby achieving lateral confinement of the current. In one embodiment, the material of the N-type structure layer and the P-type structure layer is Al x Ga 1-x As, the doping concentration of the N-type structure layer and the P-type structure layer is greater than 1e 18 cm -3 , where 0≤x≤1.

[0054] In one embodiment, the shape of the inner ring of the photoelectric confinement layer includes an irregular polygon or a regular polygon; the area where the non-ion implanted region of the inclined column intersects with the photoelectric confinement layer does not include at least one inner corner of the inner ring of the photoelectric confinement layer.

[0055] For example, when the projection shape of the photoelectric confinement pattern OA on the substrate St is an irregular geometric shape, the irregular geometric shape can be a hexagon, a pentagon, a spindle, a teardrop, a concave quadrilateral, a diamond, etc.; when the projection shape of the photoelectric confinement pattern OA on the substrate St is a regular polygon, the regular polygon can be a regular triangle, a square, a rectangle, a regular pentagon, a regular hexagon, a regular heptagon, a regular octagon, etc. It can be understood that whether it is an irregular geometric shape or a regular polygon, there will basically be corner points in the pattern, that is, the intersection of two adjacent sides. The corner points are places where current is easily concentrated, that is, the current concentration area described in this application. When a forward bias or reverse bias is applied to the device, it is more likely to cause voltage breakdown in the current concentration area, which is not conducive to the overall life and reliability of the device. Furthermore, the current concentration area at least covers the corner points of the irregular geometric shape; or the current concentration area at least covers the corner points of the regular polygon. That is, the current concentration area at least includes the focal position of the current limiting pattern OA.

[0056] In one embodiment, the shape of the non-ion implanted region of the inclined column away from the active layer on the surface of the second reflector layer does not include any inner corner of the inner ring of the photovoltaic confinement layer in the projection area of ​​the photovoltaic confinement layer.

[0057] In one embodiment, the shape of the inner ring of the photoelectric limiting layer is a regular polygon, and the shape of the non-ion implanted region of the inclined column away from the active layer on the surface of the second reflector layer is projected on the photoelectric limiting layer as an inscribed circle of the inner ring of the photoelectric limiting layer.

[0058] As an example, refer to Figure 3 and Figure 4 When the projection shape of the photoelectric restriction pattern OA on the substrate is a regular hexagon, the distribution of the non-ion implantation area A1 and the ion implantation area A2 on the side of the second reflector layer away from the active layer is as follows: Figure 3 As shown, the ion implantation area A2 at least includes the area remaining after the regular polygon is inscribed in a circle. That is, the ion implantation area A2 is Figure 3 In the case of the light blue filled area, the non-ion implanted area is the area within the circle; the distribution of the non-ion implanted area A1 and the ion implanted area A2 on the side of the second reflector layer close to the active layer is as shown in FIG. Figure 4 As shown, the ion implantation area is Figure 3 After the circle in the figure deviates, the area outside the circle and the non-ion implantation area are the areas within the circle. Thus, the non-ion implantation area in the entire second reflector layer is an inclined cylindrical area. Figure 4In this example, the non-ion-implanted region A1 of the tilted cylinder does not coincide with the three inner corners of the inner ring of the photoelectric confinement layer, thus destroying the current concentration region at the inner corner tips of a conventional laser. Therefore, in this tilted cylindrical non-ion-implanted region, the shortest current path is no longer through the inner corner tips of the photoelectric confinement layer.

[0059] As an example, the ion implantation area A2 is obtained by implanting ions into the resonant cavity structure under the shielding of a mask pattern IMP, and the projection shape of the mask pattern IMP on the substrate St is the circumscribed circle of the photoelectric restriction pattern OA.

[0060] In one embodiment, reference Figure 2 The second reflector layer further includes a C-shaped contact metal pad, with the opening of the C-shaped contact metal pad facing the first inner angle, which is an inner angle of the inner ring of the photoelectric confinement layer in the region where the non-ion-implanted region of the inclined column intersects the photoelectric confinement layer. Furthermore, the non-ion-implanted region A1 of the inclined column is tilted in a direction opposite to the opening of the C-shaped contact metal pad.

[0061] In one embodiment, the tilt angle of the non-ion implanted region of the inclined column relative to the vertical direction of the upper surface of the second reflector layer is 2°-7°. For example, the tilt angle of the non-ion implanted region of the inclined column relative to the vertical direction of the upper surface of the second reflector layer can be 3°, 5°, 6°, or 7°.

[0062] Second, please refer to Figure 6 , the present application also provides a method for preparing a surface emitting laser, comprising steps S10-S40:

[0063] Step S10, providing an epitaxial layer; wherein the epitaxial layer includes a substrate and a first reflector layer, an active region, and a second reflector layer provided on the substrate;

[0064] Step S20, performing mesa etching on the epitaxial layer to obtain a plurality of grooves, wherein the grooves expose a portion of the surface of the first reflector layer;

[0065] Step S30, performing a wet oxidation process on the epitaxial layer through the trench to form a photoelectric confinement layer in the second reflector layer; wherein the photoelectric confinement layer is a polygonal ring structure, and the inner ring of the photoelectric confinement layer includes at least three inner corners;

[0066] Step S40, applying a mask pattern on the surface of the epitaxial layer, and performing an ion implantation process on the epitaxial layer through the mask pattern to form a non-ion implantation area of ​​the inclined column in the second reflector layer, wherein the non-ion implantation area A1 of the inclined column does not overlap with at least one of the at least three inner angles of the inner ring of the photoelectric confinement layer; wherein the area outside the non-ion implantation area of ​​the inclined column is the ion implantation area.

[0067] In one embodiment, in the step of performing an ion implantation process on the epitaxial layer through the mask pattern, the ion implantation angle is inclined by 2°-7° relative to a vertical direction of an upper surface of the second reflector layer.

[0068] Specifically, such as Figure 5 As shown, the mask is a circular mask, and the projection of the mask on the substrate is the circumscribed circle of the projection of the inner ring of the photoelectric confinement layer on the substrate. Furthermore, when performing an ion implantation process on the epitaxial layer through the mask pattern, the direction of the ion implantation deviates from a direction perpendicular to the plane of the substrate. Furthermore, the angle α between the ion implantation direction and the perpendicular to the plane of the substrate is in the range of 2° to 7°.

[0069] Specifically, the complete preparation method in this embodiment can generally include the steps of epitaxial growth, oxidative trench etching, wet oxidation, deep trench etching, deep trench ion implantation, and conductive portion fabrication. The epitaxial growth, MESA trench etching, wet oxidation, deep trench etching, and deep trench ion implantation processes can be understood with reference to existing surface-emitting laser processes, and this embodiment does not specifically improve these steps. The key improvement of this application lies in the ion implantation step after wet oxidation.

[0070] For example, when performing the oxide trench etching, an inductively coupled plasma etching technique can be used, with the etching gas being a Cl2 / BCl3 mixed gas. The etching depth is controlled to be 5-8 microns, so that the first portion of the oxide trench just exposes the second portion of the first reflector layer 10. A wet oxidation process is performed on the epitaxial layer through the trench 10 to obtain a photoelectric confinement pattern OA. The wet oxidation process can be performed at a temperature of 420°C, in an oxidizing atmosphere of a mixture of water vapor and nitrogen, for 30-60 minutes. The oxidation process extends inward from the sidewalls of the oxide trench, ultimately forming a photoelectric confinement pattern OA with an irregular geometric shape or a regular polygon.

[0071] Furthermore, hydrogen ions can be used for ion implantation, with an implantation energy of 80 keV and an implantation dose of 3×10 14 cm -2The mask pattern may be made of a photoresist material (PR) with a thickness of 2-3 microns.

[0072] In one embodiment, the groove is an irregular polygon or a regular polygon connected end to end.

[0073] When the projection of the photoelectric confinement pattern OA onto the substrate St is an irregular geometric shape, the irregular geometric shape can be a hexagon, pentagon, spindle, teardrop, concave quadrilateral, diamond, etc.; when the projection of the photoelectric confinement pattern OA onto the substrate St is a regular polygon, the regular polygon can be an equilateral triangle, square, rectangle, regular pentagon, regular hexagon, regular heptagon, regular octagon, etc. It is understandable that, regardless of whether it is an irregular geometric shape or a regular polygon, there will basically be corners in the pattern, that is, the intersection of two adjacent sides. The corners are places where current is easily concentrated, that is, the current concentration area described in this application. When a forward bias or reverse bias is applied to the device, voltage breakdown is more likely to occur in the current concentration area, which is not conducive to the overall life and reliability of the device. Furthermore, the current concentration area at least covers the corners of the irregular geometric shape; or the current concentration area at least covers the corners of the regular polygon. In other words, the current concentration area at least includes the focal position of the current confinement pattern OA.

[0074] In one embodiment, before mesa etching the epitaxial layer, the method further comprises: forming a C-shaped contact metal pad on the second reflector layer.

[0075] The present invention has at least the following beneficial effects:

[0076] In the surface emitting laser provided by the present invention, the ion implantation region A2 is configured as a non-conductive region or a passivation current concentration region. Ion bombardment damages the lattice structure of the region, thereby increasing the resistivity and reducing the current passing through the region. As a result, the region of the second reflector layer other than the ion implantation region is formed into a non-ion implantation region in the form of an inclined column. This destroys the current concentration in the corresponding photoelectric confinement layer, thereby improving the reverse breakdown voltage capability of the device.

[0077] It should be understood that although Figure 6 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 6At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0078] In a third aspect, the present application provides a VCSEL chip comprising at least one laser array; the laser array comprises a plurality of surface-emitting lasers as described above; the laser array is a regularly arranged array, a randomly arranged array, or an array having multiple addressable sub-arrays. Based on the aforementioned surface-emitting lasers, the VCSEL chip of this embodiment exhibits good reliability.

[0079] In a fourth aspect, the present application provides a light source for a lidar system, comprising at least one surface emitting laser as described above or at least one VCSEL chip as described above.

[0080] In a fifth aspect, the present application provides a laser radar system, comprising a transmitting component and a receiving component, wherein the transmitting component adopts the above-mentioned light source for the laser radar system.

[0081] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The above-described embodiments merely represent several implementation methods of the embodiments of the present application. The descriptions thereof are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the concept of the embodiments of the present application, and these all fall within the scope of protection of the embodiments of the present application. Therefore, the scope of protection of the patent of the embodiments of the present application shall be based on the appended claims.

Claims

1. A surface emitting laser, characterized in that comprising a substrate and a resonant cavity structure provided on the substrate; The resonant cavity structure comprises a first reflector layer, an active layer, and a second reflector layer sequentially located on the substrate; A photoelectric confinement layer is formed in the second reflector layer, wherein the photoelectric confinement layer is a polygonal ring structure, and an inner ring of the photoelectric confinement layer includes at least three inner corners; as well as The second reflector layer further includes a non-ion implanted region of an inclined column, wherein the non-ion implanted region of the inclined column does not overlap with at least one of the at least three inner angles of the inner ring of the photoelectric confinement layer; In the second reflector layer, the area outside the non-ion implantation area of ​​the inclined columns is the ion implantation area.

2. The surface emitting laser according to claim 1, wherein The shape of the inner ring of the photoelectric confinement layer includes an irregular polygon or a regular polygon; The region where the non-ion implantation region of the inclined column intersects with the photoelectric confinement layer at least does not include an inner corner of an inner ring of the photoelectric confinement layer.

3. The surface emitting laser according to claim 2, wherein The second reflector layer also includes a C-shaped contact metal pad, and the opening of the C-shaped contact metal pad faces the first inner angle, which is an inner angle of the inner ring of the photoelectric limiting layer in the area where the non-ion implantation area of ​​the inclined column intersects the photoelectric limiting layer.

4. The surface emitting laser according to claim 2, wherein The shape of the non-ion implanted region of the inclined column away from the active layer on the surface of the second reflector layer does not include any inner corner of the inner ring of the photovoltaic confinement layer in the projection area of ​​the photovoltaic confinement layer.

5. The surface emitting laser according to claim 4, wherein The inner ring of the photoelectric limiting layer is a regular polygon, and the projection of the non-ion implanted region of the inclined column away from the active layer on the surface of the second reflector layer on the photoelectric limiting layer is an inscribed circle of the inner ring of the photoelectric limiting layer.

6. The surface emitting laser according to any one of claims 1 to 5, characterized in that The tilt angle of the non-ion implantation region of the inclined column relative to the vertical direction of the upper surface of the second reflector layer is 2°-7°.

7. A method for preparing a surface emitting laser, characterized in that: include: Providing an epitaxial layer; wherein the epitaxial layer includes a substrate and a first reflector layer, an active region, and a second reflector layer sequentially arranged on the substrate; performing mesa etching on the epitaxial layer to obtain a plurality of grooves, wherein the grooves expose a portion of the surface of the first reflector layer; Performing a wet oxidation process on the epitaxial layer through the trench to form a photoelectric confinement layer in the second reflector layer; wherein the photoelectric confinement layer is a polygonal ring structure, and the inner ring of the photoelectric confinement layer includes at least three inner corners; Applying a mask pattern on the surface of the epitaxial layer and performing an ion implantation process on the epitaxial layer through the mask pattern to form a non-ion implantation region of an inclined column in the second reflector layer, wherein the non-ion implantation region of the inclined column does not overlap with at least one of the at least three inner corners of the inner ring of the photoelectric confinement layer; Wherein, the area outside the non-ion implantation area of ​​the inclined column is the ion implantation area.

8. The method for preparing a surface emitting laser according to claim 7, wherein: The groove is an irregular polygon or a regular polygon connected end to end.

9. The method for preparing a surface emitting laser according to claim 8, wherein: Before mesa etching the epitaxial layer, the method further includes: forming a C-shaped contact metal pad on the second reflector layer.

10. The method for preparing a surface emitting laser according to claim 9, wherein: In the step of performing an ion implantation process on the epitaxial layer through the mask pattern, the ion implantation angle is inclined by 2°-7° relative to a vertical direction of an upper surface of the second reflector layer.

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