Laser, laser chip and laser radar

Abstract

The invention provides a laser, a laser chip and a laser radar, and the laser comprises a substrate which is provided with impurities of a first conduction type; the first reflecting mirror and the second reflecting mirror are sequentially stacked on one side of the substrate, the first reflecting mirror comprises a first reflecting part and a second reflecting part, the first reflecting part and the second reflecting part are sequentially located on the substrate, and the second reflecting part and the second reflecting mirror have impurities; the active layer is located between the first reflecting mirror and the second reflecting mirror, and the first reflecting part is suitable for enabling the active layer to be electrically isolated from the substrate. The resonant cavity is formed on the conductive substrate, the quality of the epitaxial material can be effectively improved, the quality of the resonant cavity is improved, and the device yield is improved; the first reflection part close to the substrate is treated as an insulating layer, so that the electrical insulation performance of the substrate side can be improved without additionally increasing the thickness of an epitaxial material.

Description

Technical Field

[0001] The present disclosure relates to the field of laser detection, and particularly to a laser, a laser chip, and a lidar. Background Art

[0002] A conventional Vertical Cavity Surface Emitting Laser (VCSEL) generally includes a lower Distributed Bragg Reflector (DBR), an active region, a current confinement layer, and an upper DBR that are sequentially epitaxially grown on an N-type doped substrate. Among them, current is injected into the active region through an electrode; the material in the active region is excited to emit light, and resonates in the resonant cavity formed by the upper DBR and the lower DBR, forming a strong light beam with the same propagation direction, frequency, and phase.

[0003] In VCSEL design, multiple VCSEL units are arranged on the same chip to obtain higher integration. According to different usage scenarios and driving methods, multiple VCSEL units can adopt various connection methods such as series driving, parallel driving, and individually addressable driving. When multiple VCSEL units are integrated on the same chip and adjacent VCSEL units are not simultaneously driven to emit light, electrical isolation needs to be performed on the adjacent VCSEL units.

[0004] Generally, adjacent VCSEL units are directly connected to the substrate. While existing VCSEL units achieve electrical insulation on the substrate side, it is difficult to ensure good epitaxial crystal quality and device manufacturing yield. Summary of the Invention

[0005] The problem solved by the present disclosure is how to improve the epitaxial crystal quality and device manufacturing yield while achieving electrical insulation on the substrate side.

[0006] To solve the above problems, the present disclosure provides a laser, comprising:

[0007] A substrate having impurities of a first conductivity type; a first mirror and a second mirror, the first mirror and the second mirror are sequentially stacked on one side of the substrate, wherein the first mirror includes: a first reflection portion and a second reflection portion, the first reflection portion and the second reflection portion are sequentially located on the substrate, and the second reflection portion and the second mirror have impurities; an active layer located between the first mirror and the second mirror, and the first reflection portion is adapted to electrically isolate the active layer from the substrate.

[0008] Optionally, the thickness of the first reflective portion is determined based on the wavelength of the light generated by the laser.

[0009] Optionally, the first reflective portion includes: a first doped layer having impurities of a second conductivity type.

[0010] Optionally, the doping concentration of the first doped layer is lower than the doping concentration of the second mirror.

[0011] Optionally, the first reflective portion further includes: a second doped layer having impurities of a first conductivity type, and the second doped layer is located at least in one of the following positions: between the first doped layer and the substrate; and between the first doped layer and the second reflective portion.

[0012] Optionally, the doping concentration of the second doped layer is lower than the doping concentration of the second reflective portion.

[0013] Optionally, the first reflective portion further includes: an intrinsic layer located at least in one of the following positions: on the side of the first doped layer away from the substrate; on the side of the first doped layer facing the substrate.

[0014] Optionally, the first mirror further includes: a current diffusion layer located between the first reflective portion and the second reflective portion.

[0015] Optionally, it further includes: a current diffusion layer located between the first reflective portion and the second reflective portion.

[0016] Optionally, the current diffusion layer has impurities of a first conductivity type, and the doping concentration of the current diffusion layer is greater than the doping concentration of the second reflective portion.

[0017] Optionally, the first reflective portion includes: an intrinsic layer.

[0018] Optionally, the first mirror further includes: a third reflective portion located between the first reflective portion and the substrate.

[0019] Optionally, the third reflective portion includes an intrinsic layer; or, the third reflective portion has impurities of a first conductivity type.

[0020] Optionally, the doping concentration of the third reflective portion is not higher than the doping concentration of the second reflective portion.

[0021] Optionally, the direction in which the first mirror points to the second mirror is consistent with the laser emission direction.

[0022] Optionally, the first mirror and the second mirror are distributed Bragg reflectors.

[0023] Optionally, the first conductivity type is n-type; the second conductivity type is p-type.

[0024] Optionally, it further includes: a first electrode; a second electrode, and the second electrode is located on a side of the second mirror away from the active layer.

[0025] Optionally, it further includes: a current diffusion layer, and the current diffusion layer is located between the first reflection portion and the second reflection portion; a part of the current diffusion layer is exposed by the second reflection portion, and the first electrode is located on the part of the current diffusion layer exposed by the second reflection portion.

[0026] Correspondingly, the present invention further provides a laser array, including:

[0027] A plurality of lasers, and each laser includes: a substrate having impurities of a first conductivity type; a first mirror and a second mirror, and the first mirror and the second mirror are sequentially stacked on one side of the substrate. Among them, the first mirror includes: a first reflection portion and a second reflection portion, the first reflection portion and the second reflection portion are sequentially located on the substrate, and the second reflection portion and the second mirror have impurities; an active layer, and the active layer is located between the first mirror and the second mirror, and the first reflection portion is adapted to electrically isolate the active layer from the substrate.

[0028] Optionally, it further includes: an isolation structure, and the isolation structure is located between adjacent lasers and extends from a surface of the first reflection portion away from the substrate side towards the substrate.

[0029] Optionally, the laser further includes: a current diffusion layer, and the current diffusion layer is located between the first reflection portion and the second reflection portion; the isolation structure extends from a surface of the current diffusion layer away from the substrate side into the first reflection portion.

[0030] Optionally, the first reflection portion includes: an intrinsic layer; and the isolation structure passes through at least a part of the thickness of the first reflection portion.

[0031] Optionally, the first reflection portion includes: a first doped layer having impurities of a second conductivity type; and the isolation structure passes through the entire thickness of the first reflection portion.

[0032] Optionally, the substrates of at least some of the lasers are integrally connected.

[0033] Optionally, the laser further includes: a third reflection portion, and the third reflection portion is located between the first reflection portion and the substrate; the third reflection portions of at least some of the lasers are integrally connected.

[0034] In addition, the present invention also provides a lidar, comprising:

[0035] A light source adapted to generate detection light, the light source comprising: at least one laser, the laser comprising: a substrate having impurities of a first conductivity type; a first mirror and a second mirror, the first mirror and the second mirror being stacked in sequence on one side of the substrate, wherein the first mirror comprises: a first reflection portion and a second reflection portion, the first reflection portion and the second reflection portion are located on the substrate in sequence, the second reflection portion and the second mirror have impurities; an active layer located between the first mirror and the second mirror, the first reflection portion being adapted to electrically isolate the active layer from the substrate; a detector adapted to receive the echo light formed by the reflection of the detection light by an object.

[0036] Compared with the prior art, the technical solution of the present disclosure has the following advantages:

[0037] In the technical solution of the present disclosure, the substrate has impurities of a first conductivity type; the first mirror is divided into a first reflection portion for electrically isolating the active layer from the substrate and a second reflection portion having impurities. The conductive substrate has better quality and lower defect density than the insulating substrate. Therefore, forming a resonant cavity on the conductive substrate can effectively improve the quality of the epitaxial crystal, improve the device yield and reliability; treating the first reflection portion close to the substrate as an insulating layer can achieve electrical insulation on the substrate side without additionally increasing the thickness of the epitaxial layer, which can reduce the epitaxial time and is beneficial to improving the quality of the epitaxial crystal and the device yield.

[0038] In an alternative embodiment of the present disclosure, the first reflection portion may include an intrinsic layer, or the first reflection portion may include a first doped layer having impurities of a second conductivity type. Using an intrinsic material to improve the electrical insulation performance on the substrate side, or using a reverse-biased junction to improve the electrical insulation performance on the substrate side, can effectively reduce the doping concentration of the entire first mirror and effectively reduce the optical loss.

[0039] In an alternative embodiment of the present disclosure, the first mirror further includes a third reflection portion located between the first reflection portion and the substrate, and the third reflection portion includes an intrinsic layer or impurities of a first conductivity type. The setting of the third reflection portion can effectively improve the reflectivity of the first mirror and improve the beam quality of the laser.

[0040] In an alternative embodiment of the present disclosure, the first mirror and the second mirror are distributed Bragg reflectors. By using part of the film layer of the distributed Bragg reflector as an insulating layer treatment, it is possible to ensure the insulation performance on the substrate side without growing an additional epitaxial layer as the insulating layer, effectively reducing the thickness of the overall epitaxial growth crystal, shortening the epitaxial growth time, and facilitating cost reduction and improvement of the quality of the epitaxial crystal.

[0041] In the technical solution of the present disclosure, the laser array further includes: an isolation structure located between adjacent lasers, and the isolation structure extends from the surface of the first reflecting portion away from the substrate side towards the substrate. The setting of the isolation structure can further improve the electrical insulation performance between adjacent lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only the embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings. The drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the embodiments of the present disclosure to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:

[0043] Figure 1 is a schematic cross-sectional structure diagram of the first embodiment of the laser of the present disclosure;

[0044] Figure 2 is a schematic cross-sectional structure diagram of the second embodiment of the laser of the present disclosure;

[0045] Figure 3 is a schematic cross-sectional structure diagram of the third embodiment of the laser of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present disclosure. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0047] In the description of the present disclosure, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present disclosure. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present disclosure, "a plurality" means two or more unless otherwise specifically defined.

[0048] In the description of the present disclosure, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection: it can be a mechanical connection, an electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the connection inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0049] In the present disclosure, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0050] The following disclosure provides many different embodiments or examples for implementing different structures of the present disclosure. To simplify the disclosure of the present disclosure, components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present disclosure. In addition, the present disclosure may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present disclosure provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0051] As can be seen from the background art, there are problems in the prior art lasers that it is difficult to balance electrical insulation on the substrate side and the quality of the epitaxial crystal.

[0052] According to the different electrical conductivity of the substrate, there are mainly two methods to achieve electrical insulation on the substrate side of the laser in the prior art. One is to use an insulating substrate (Semi-Isolated Substrate, S.I.Substrate) to achieve electrical insulation between adjacent laser units, and directly form a resonant cavity on the insulating substrate. This method is simple, direct, and has good insulation effect, and can also achieve insulation effect at a higher voltage. However, the quality of the insulating substrate is generally poor and has many defects, and the quality of the epitaxial layer formed by epitaxial growth on the insulating substrate is poor, and the yield of the finally formed device is low.

[0053] Another method is to use a conductive substrate, such as an N-type substrate, to achieve electrical insulation on the substrate side by epitaxially growing an insulating structure on the conductive substrate. Since the quality of the conductive substrate is high, the quality of the formed epitaxial crystal is high, and the yield of the formed device can be well guaranteed. However, since a conductive substrate is used on the substrate side, the insulation effect is not good; in order to ensure electrical insulation on the substrate side, an additional insulating structure needs to be formed on the conductive substrate, so the epitaxial growth thickness is large, the process cost is high, and the manufacturing time is long; the large epitaxial growth thickness is also likely to increase the possibility of defects and affect the yield of the finally formed device.

[0054] It can be seen that it is difficult to ensure good epitaxial crystal quality and device manufacturing yield while achieving electrical insulation on the substrate side in the prior VCSEL units.

[0055] To solve the above technical problems, the present disclosure provides a laser, including:

[0056] A substrate having impurities of a first conductivity type; a first mirror and a second mirror, the first mirror and the second mirror being stacked in sequence on one side of the substrate, wherein the first mirror includes: a first reflection portion and a second reflection portion, the first reflection portion and the second reflection portion are located on the substrate in sequence, and the second reflection portion and the second mirror have impurities; an active layer located between the first mirror and the second mirror, and the first reflection portion is adapted to electrically isolate the active layer from the substrate.

[0057] The technical solution of the present disclosure forms a resonant cavity on a conductive substrate, which can effectively improve the quality of epitaxial crystals, improve the yield and reliability of devices; treating the first reflection portion close to the substrate as an insulating layer can achieve electrical insulation on the substrate side without additionally increasing the thickness of the epitaxial layer, which can reduce the epitaxial time and is beneficial to improving the quality of epitaxial crystals and the yield of devices.

[0058] To make the above objects, features, and advantages of the present disclosure more obvious and understandable, the following detailed description of specific embodiments of the present disclosure will be made with reference to the accompanying drawings.

[0059] Reference Figure 1 shows a schematic cross-sectional structure diagram of a first embodiment of a laser of the present disclosure.

[0060] As Figure 1 shown, the laser includes a substrate 110, a first mirror 120, a second mirror 130, and an active layer 140. Among them, the substrate 110 has impurities of a first conductivity type. The first mirror 120 and the second mirror 130 are stacked in sequence on one side of the substrate 110, wherein the first mirror 120 includes: a first reflection portion 121 and a second reflection portion 122, and the first reflection portion 121 and the second reflection portion 122 are located on the substrate 110 in sequence. The second reflection portion 122 and the second mirror 130 have impurities. The active layer 140 is located between the first mirror 120 and the second mirror 130, and the first reflection portion 121 is adapted to electrically isolate the active layer 140 from the substrate 110.

[0061] Forming a resonant cavity on a conductive substrate can effectively improve the quality of epitaxial crystals, improve the quality of the resonant cavity, and improve the yield of devices; treating the first reflection portion 121 close to the substrate 110 as an insulating layer can improve the electrical insulation performance on the substrate side without additionally increasing the thickness of the epitaxial layer.

[0062] The following will detail the specific technical solutions of the laser embodiments of the present disclosure with reference to the accompanying drawings.

[0063] The substrate 110 can provide a process platform during the formation of the laser.

[0064] The substrate 110 has impurities of a first conductivity type, the substrate 110 is a conductive substrate, and the substrate 110 is a doped semiconductor. The conductive substrate has better quality and fewer structural defects. The crystal quality formed by epitaxial growth on the conductive substrate is higher, and the yield of the formed devices is higher.

[0065] In some embodiments of the present disclosure, the first conductivity type is n-type, and the substrate 110 is an n-type substrate. The n-type substrate has better quality and lower defect density, which can further improve the epitaxial crystal quality.

[0066] In some specific embodiments, the laser is a vertical cavity surface emitting laser, and the material of the substrate 110 may include one of GaAs, InP, GaSb, or InSb.

[0067] The active layer 140 is located on the substrate 110. The active layer 140 has a gain medium capable of achieving population inversion, generating stimulated emission amplification.

[0068] In some embodiments of the present disclosure, the active layer 140 includes a plurality of multi quantum wells (MQWs) structures, that is, the active layer 140 is a quantum well structure formed by alternately growing thin films of two materials with narrow bandgap and wide bandgap. For example, the active layer 140 includes 2 to 3 groups of quantum well structures. For example, when the resonant cavity is the resonant cavity of a 940 nm laser, the quantum well structure is an InGaAs / GaAs quantum well structure or an InGaAs / GaAsP quantum well structure.

[0069] In other embodiments, the active layer 140 includes a multi-junction structure, where each junction includes a plurality of quantum wells. A tunneling structure may be provided between adjacent junctions to reduce the resistivity. The active layer 140 including the multi-junction structure can obtain higher luminous intensity and luminous efficiency to improve the optical power and energy conversion efficiency of the laser.

[0070] The first mirror 120 and the second mirror 130 respectively form the reflecting surfaces of the resonant cavity; wherein the first mirror 120 is located on the side of the active layer 140 close to the substrate 110, and the second mirror 130 is located on the side of the active layer 140 far from the substrate 110; the light generated by the active layer 140 propagates back and forth between the first mirror 120 and the second mirror 130.

[0071] The conductivity type of the impurities in the first mirror 120 close to the substrate 110 is the same as the conductivity type of the impurities in the substrate 110, and the first mirror 120 has impurities of the first conductivity type.

[0072] In some embodiments, the first conduction type is n-type, the first mirror 120 is an n-type mirror, and the first mirror 120 has n-type impurities.

[0073] In some specific embodiments, the first mirror 120 and the second mirror 130 are distributed Bragg reflectors. The first mirror 120 and the second mirror 130 are Bragg reflectors (distributed brag reflector, abbreviated as DBR). Specifically, the Bragg reflector includes a high refractive index thin film and a low refractive index thin film, and the high refractive index thin film and the low refractive index thin film are alternately arranged. An adjacent high refractive index thin film and low refractive index thin film form a pair. The reflectivity of the distributed Bragg reflector is related to the number of pairs of high and low refractive index thin films therein.

[0074] It should be noted that in some embodiments of the present disclosure, in the first mirror and the second mirror, the high refractive index thin film and the low refractive index thin film can be made of the same material. For example, the first mirror and the second mirror can be alternately arranged Al x Ga 1-x As / Al 1-y Ga y As thin films, where the values of x and y can be different. In some other embodiments of the present disclosure, in the first mirror and the second mirror, the high refractive index thin film and the low refractive index thin film can be composed of multiple heterogeneous materials and different layer combinations. By designing the thickness of the material film layer and the refraction or reflection at the interface, the reflectivity of the first mirror and the second mirror is ensured.

[0075] In order to ensure the gain of the resonant cavity, the first mirror 120 and the second mirror 130 must have a considerable number of periods to meet the requirement of high reflectivity. Moreover, in order to ensure that the output laser has a narrow linewidth, the light generated by the active region 120 forms a standing wave in the resonant cavity after being reflected multiple times by the first mirror 120 and the second mirror 130. Therefore, the first mirror 120 and the second mirror 130 need to have a relatively high reflectivity.

[0076] In some specific embodiments, the reflectivity of the first mirror 120 is greater than or equal to 99.9%, the reflectivity of the second mirror 130 is greater than or equal to 98%, and the laser exits in the direction from the first mirror 120 to the first mirror 130. In some other embodiments, the reflectivity of the first mirror 120 is greater than or equal to 98%, the reflectivity of the second mirror 130 is greater than or equal to 99.9%, and the laser exits in the direction from the second mirror 130 to the first mirror 120.

[0077] Ensure the overall number of cycles of the first mirror 120 and the second mirror 130, which can ensure that the first mirror 120 and the second mirror 130 meet the high reflectivity requirements to form a resonant cavity, can ensure the gain of the resonant cavity, and ensure the luminous intensity.

[0078] As Figure 1 In some embodiments as shown, the direction in which the first mirror 120 points to the second mirror 130 is consistent with the laser output direction A, and the reflectivity of the first mirror 120 is greater than that of the second mirror 130.

[0079] In some embodiments of the present disclosure, the second mirror 130 has impurities of the second conductivity type. Specifically, the second conductivity type is p-type, and the second mirror 130 has p-type impurities.

[0080] In other embodiments of the present disclosure, the second mirror 130 includes impurities of the first conductivity type. Specifically, the first conductivity type is n-type, and the first mirror 120 has n-type impurities. At the same doping concentration, the epitaxial layer doped with n-type has a lower resistivity. The second mirror 130 also includes n-type impurities, which can effectively reduce the resistivity of the mirror and improve the power of the laser.

[0081] In other embodiments, the second mirror 130 includes impurities of the first conductivity type and impurities of the second conductivity type. Specifically, a part of the epitaxial layer on the side of the second mirror 130 away from the first mirror 120 includes impurities of the first conductivity type; a part of the epitaxial layer on the side of the second mirror 130 facing the first mirror 120 includes impurities of the second conductivity type.

[0082] The first mirror 120 includes a first reflection portion 121 and a second reflection portion 122; specifically, the first reflection portion 121, the second reflection portion 122, the active layer 140, and the second mirror 130 of the first mirror 120 are sequentially stacked on the substrate 110.

[0083] In some embodiments of the present disclosure, the thickness of the first reflection portion 121 is determined based on the wavelength of the light generated by the laser. The thickness of the first reflection portion 121 is determined based on the wavelength of the light generated by the laser to ensure stronger reflection coherence, which is conducive to forming a standing wave in the resonant cavity. Herein, the thickness refers to the size of the first reflection portion 121 in the direction perpendicular to the surface of the substrate 110. In some embodiments, the first mirror 120 is a distributed Bragg reflector, and the first reflection portion 121 includes paired high-refractive-index thin films and low-refractive-index thin films; in the first reflection portion 121, the thickness of any high-refractive-index thin film and any low-refractive-index thin film is determined based on the wavelength generated by the laser, and the overall thickness of the first reflection portion 121 is related to both the wavelength generated by the laser and the number of pairs of high-refractive-index thin films and low-refractive-index thin films therein.

[0084] It should be noted that the thickness of the second reflection portion 122 is also determined based on the wavelength of the light generated by the laser. The thickness of the second reflection portion 122 is determined based on the wavelength of the light generated by the laser to ensure stronger reflection coherence, which is conducive to forming a standing wave in the resonant cavity. The second reflection portion 122 also includes paired high-refractive-index thin films and low-refractive-index thin films; in the second reflection portion 122, the thickness of any high-refractive-index thin film and any low-refractive-index thin film is determined based on the wavelength generated by the laser, and the overall thickness of the second reflection portion 122 is also related to both the wavelength generated by the laser and the number of pairs of high-refractive-index thin films and low-refractive-index thin films therein.

[0085] By determining the thickness of the first reflection portion 121 or the second reflection portion 122 based on the wavelength of the light generated by the laser, the first reflection portion 121 or the second reflection portion 122 can function to reflect light, and the light generated by the laser can be superimposed and enhanced after being reflected by the first reflection portion 121 or the second reflection portion 122.

[0086] It should also be noted that the second reflection portion 122 is also suitable for realizing the electrical connection or electrical conduction between the active layer 140 and the external circuit. The second reflection portion 122 has impurities of a first conductivity type. In some specific embodiments, the second reflection portion 122 has n-type impurities.

[0087] In a specific implementation, the current flow direction of the laser is from the second mirror 130 to the second reflection portion 122, and the second mirror 130 and the second reflection portion 122 include impurities of a first conductivity type. A tunneling junction is provided on the side of the second mirror 130 facing the second reflection portion 122 to reduce the resistivity and improve the power of the laser.

[0088] In some other specific implementations, the second reflector 130 includes impurities of the first conductivity type and impurities of the second conductivity type, and the second reflector 122 includes impurities of the first conductivity type. The current of the laser flows in the direction in which the second reflector 130 points to the second reflector 122. A tunnel junction is provided in the second reflector 130 to reduce the resistivity. Among them, the second reflector on the side of the tunnel junction facing the second reflector 122 has impurities of the second conductivity type, and the second reflector on the side of the tunnel junction away from the second reflector 122 has impurities of the first conductivity type.

[0089] In some other specific implementations, the second reflector 130 includes impurities of the first conductivity type, and the second reflector 122 includes impurities of the first conductivity type. The current of the laser flows in the direction in which the second reflector 122 points to the second reflector 130. A tunnel junction is provided on the side of the second reflector 122 facing the second reflector 130 to reduce resistivity and increase the power of the laser.

[0090] The first reflective portion 121 is located between the second reflective portion 122 and the substrate 110 , and the first reflective portion 121 is used to achieve electrical insulation of the laser on the substrate side. In some embodiments, the first reflective portion 121 is used to achieve electrical insulation between the active layer 140 and the substrate 110 .

[0091] In some embodiments of the present disclosure, the first reflecting part 121 includes: an intrinsic layer. Specifically, the material of the first reflecting part 121 is an intrinsic material, the first reflecting part 121 is not doped, and the first reflecting part 121 does not include impurities. In the first reflecting part 121, both the high refractive index film and the low refractive index film are undoped. Undoped intrinsic materials have a high resistivity and a low conductivity, and can well achieve electrical insulation between the active layer 140 and the substrate 110 with impurities. The lower the impurity concentration of the reflecting part, the lower the corresponding optical absorption and the lower the absorption loss. The reflecting part 121 includes an intrinsic material, which can reduce light energy loss and increase the optical power of the laser.

[0092] It should be noted that the thickness of the intrinsic material is related to its electrical insulation performance. The larger the size of the intrinsic material in the current transmission direction, the greater its resistance. In some embodiments of the present disclosure, the thickness of the first reflective portion 121 is not less than 0.5 μm to ensure the electrical insulation performance of the laser substrate side. In some preferred embodiments, the thickness of the first reflective portion 121 is not less than 1 μm to further improve the electrical insulation performance of the laser substrate side.

[0093] The first reflection portion 121 not only serves as a part of the first reflector 120 to form a part of a reflecting surface of the resonant cavity, but also realizes electrical insulation on the substrate side of the laser through an insulating layer treatment. Without adding an additional insulating layer, the insulation performance between the conductive substrate can be ensured, and on the premise of ensuring the reflectivity of the first reflector 120, the overall logarithm of the first reflector 120 can be controlled or even reduced, which is beneficial to improving the epitaxial crystal quality, the quality of the resonant cavity, and the device yield.

[0094] Figure 1 In some specific embodiments shown, the first reflector 120 further includes: a current diffusion layer 124, and the current diffusion layer 124 is located between the first reflection portion 121 and the second reflection portion 122.

[0095] The current diffusion layer 124 is connected to the second reflection portion 122. The current diffusion layer 124 is located between the first reflection portion 121 and the second reflection portion 122, and can realize the electrical connection or electrical conduction between the second reflection portion 122 and the external circuit, forming a current path of the resonant cavity.

[0096] Specifically, the current diffusion layer 124 is in direct contact with the second reflection portion 122. The second reflection portion 122 is located on the surface of the current diffusion layer 124 facing away from the substrate 110 and is in direct contact with the surface of the current diffusion layer 124 facing away from the substrate 110.

[0097] In addition, Figure 1 In some embodiments shown, the current diffusion layer 124 is also in direct contact with the first reflection portion 121. The current diffusion layer 124 is located on the surface of the first reflection portion 121 facing away from the substrate 110 and is in direct contact with the surface of the first reflection portion 121 facing away from the substrate 110.

[0098] Exemplarily, the refractive index difference between the current diffusion layer 124 and the adjacent epitaxial layer is relatively large, and the reflection effect at the interface is strong. The current diffusion layer 124 can be used as a part of the first reflector 120. The thickness of the current diffusion layer 124 is determined based on the wavelength of the light generated by the laser to facilitate the reflection coherence of light and the formation of standing waves.

[0099] In some embodiments of the present disclosure, the current diffusion layer 124 has impurities of a first conductivity type, and the doping concentration of the current diffusion layer 124 is greater than the doping concentration of the second reflection portion 122. The current diffusion layer 124 adopts a higher doping concentration, which can effectively reduce the resistance and improve the conductivity. In some specific embodiments, the current diffusion layer 124 includes n-type impurities, and the doping concentration of the current diffusion layer 124 is 2E18 atom / cm 3to 5E18 atom / cm 3 within this range to ensure its good electrical conductivity.

[0100] In some specific embodiments, the thickness of the current diffusion layer 124 is in the range of 0.5 μm to 5 μm. In some specific embodiments, the material of the current diffusion layer 124 is at least one of GaAs and AlGaAs.

[0101] In some other embodiments of the present disclosure, the laser includes a current diffusion layer 124, and the current diffusion layer 124 is located between the first reflection portion 121 and the second reflection portion 122.

[0102] Exemplarily, the refractive index difference between the current diffusion layer 124 and the adjacent epitaxial layer is small, and the reflection effect at the interface is small. The current diffusion layer 124 has impurities of the first conductivity type, and the doping concentration of the current diffusion layer 124 is greater than the doping concentration of the second reflection portion 122 to effectively reduce the resistance and improve the electrical conductivity.

[0103] Continuing to refer to Figure 1 , in some specific embodiments, the first mirror 120 further includes: a third reflection portion 123, and the third reflection portion 123 is located between the first reflection portion 121 and the substrate 110. The third reflection portion 123 serves as part of the first mirror 120 to enable the reflectivity of the first mirror 120 to meet the preset requirements. Specifically, the third reflection portion 123 is in direct contact with the substrate 110. The third reflection portion 123 is located on the surface of the substrate 110 and is in direct contact with the surface of the substrate 110.

[0104] In addition, Figure 1 in some embodiments shown, the third reflection portion 123 is also in direct contact with the first reflection portion 121. The third reflection portion 123 is located on the surface of the first reflection portion 121 facing the substrate 110 and is in direct contact with the surface of the first reflection portion 121 facing the substrate 110.

[0105] Specifically, in order to ensure that the third reflection portion 123 can improve the reflectivity of the first mirror 120, the thickness of the third reflection portion 123 is determined based on the wavelength of the light generated by the laser. In some embodiments, the third reflection portion 123 includes paired high refractive index thin films and low refractive index thin films; in the third reflection portion 123, the thickness of any high refractive index thin film and any low refractive index thin film is determined based on the wavelength of the light generated by the laser, and the overall thickness of the third reflection portion 123 is related to the wavelength of the light generated by the laser and the number of pairs of high refractive index thin films and low refractive index thin films therein.

[0106] In some embodiments of the present disclosure, the third reflective portion 123 has impurities of a first conductivity type. The third reflective portion 123 is made of a material having impurities of a first conductivity type, which can make the lattice matching degree between the third reflective portion 123 and the substrate 110 having impurities of the same first conductivity type higher, effectively ensuring the quality of epitaxial growth and being beneficial to the improvement of device performance and device yield.

[0107] In some specific embodiments, the doping concentration of the third reflective portion 123 is not higher than that of the second reflective portion 122. Preferably, the doping concentration of the third reflective portion 123 is lower than that of the second reflective portion 122. The third reflective portion 123 has no conductivity requirement. Reducing the doping concentration of the third reflective portion 123 can reduce the absorption of light while obtaining epitaxial crystals of higher quality. In some embodiments, the doping concentration of the third reflective portion 123 is in the range of 1E16 atom / cm 3 to 1E18 atom / cm 3 .

[0108] In some embodiments, the third reflective portion 123 includes an intrinsic layer. The third reflective portion 123 may not be doped with impurities, further reducing the absorption of light, reducing light loss, and increasing the power of the laser.

[0109] As Figure 1 shown, in some embodiments of the present disclosure, the laser further includes: a first electrode 151; a second electrode 152, and the second electrode 152 is located on the side of the second mirror 130 away from the active layer 140.

[0110] The first electrode 151 and the second electrode 152 are used to connect the laser to an external circuit to supply power to the laser.

[0111] In some embodiments of the present disclosure, the first electrode 151 and the second electrode 152 are respectively connected to the nearby mirrors to achieve electrical connection. As Figure 1 shown, the first electrode 151 is connected to the first mirror 120, and the second electrode 152 is connected to the second mirror 130.

[0112] Specifically, the second electrode 152 is located on the side of the second mirror 130 facing away from the active layer 140. As Figure 1 shown in some embodiments, the laser further includes a contact layer 131, the contact layer 131 is located between the second electrode 152 and the second mirror 130, and the second electrode 150 is electrically connected to the second mirror 130 through the contact layer 131. In order to reduce the resistance, the contact layer 131 has impurities of the same conductivity type as the second mirror 130.

[0113] In some specific embodiments, the contact layer 131 is located on the surface of the second mirror 130 facing away from the substrate 110 and is in direct contact with the surface of the second mirror 130 facing away from the substrate 110; the second electrode 150 is located on the surface of the contact layer 131 facing away from the substrate 110 and is in direct contact with the surface of the contact layer 131 facing away from the substrate 110.

[0114] Figure 1 In some of the illustrated embodiments, the direction in which the first mirror 120 points to the second mirror 130 is consistent with the laser emission direction A, and the light generated by the laser is emitted from the second mirror 130; the second electrode 152 is located on a part of the second mirror 130. Specifically, the second electrode 152 is annular, and a part of the second mirror 130 is exposed at the center of the annulus.

[0115] In some other embodiments, the second electrode 152 is located on the surface of a part of the contact layer 131. The second electrode 152 is annular, and a part of the surface of the contact layer 131 is exposed at the center of the annulus, forming a laser emission hole.

[0116] The epitaxial layer on the side of the first reflection portion 121 or the current diffusion layer 124 facing away from the substrate 110 includes the second reflection portion 122, the active layer 140, and the second mirror 130. Its area on the surface parallel to the substrate is smaller than that of the first reflection portion 121, constituting a light-emitting mesa protruding from the second reflection portion 121 or the current diffusion layer 124.

[0117] As Figure 1 shown, in the lidar, the current diffusion layer 124 is located between the first reflection portion 121 and the second reflection portion 122; a part of the current diffusion layer 124 is exposed between the light-emitting mesas of adjacent lasers, and the first electrode 151 is located on the exposed part of the current diffusion layer 124.

[0118] In some other embodiments, a part of the first reflection portion 121 is exposed between the light-emitting mesas of adjacent lasers, and the first electrode 151 is located on the exposed part of the first reflection portion 121.

[0119] Specifically, the current diffusion layer 124 includes: a core region (not marked in the figure) and an extension region (not marked in the figure), where the light-emitting mesa of the laser is located on the current diffusion layer 124 in the core region, and the light-emitting mesa of the laser exposes the current diffusion layer in the extension region.

[0120] In some specific embodiments, the first electrode 151 is located on the surface of the current diffusion layer 124 in the extended region and is in direct contact with the surface of the current diffusion layer 124 in the extended region. The current diffusion layer 124 extends in a plane parallel to the surface of the substrate 110, enabling lateral conduction of current and improving the convenience of connection to external current. Both the first electrode 151 and the second electrode 152 are located on the same side of the substrate, thereby reducing the process difficulty of subsequent electrical connection.

[0121] It should be noted that Figure 1 In some of the illustrated embodiments, the first reflective portion 121 includes: an intrinsic layer, which uses the high insulation and low conductivity of the intrinsic material to achieve electrical insulation from the conductive substrate. In other embodiments of the present disclosure, the first reflective portion 121 employs a doped layer with impurities.

[0122] Referring to Figure 2 , a cross-sectional structural schematic diagram of a second embodiment of the laser of the present disclosure is shown.

[0123] As Figure 2 shown, the laser includes a substrate 210, a first mirror 220, a second mirror 230, and an active layer 240.

[0124] Among them, the substrate 210 has impurities of the first conductivity type. The first mirror 220 and the second mirror 230 are sequentially stacked on one side of the substrate 210. Among them, the first mirror 220 includes: a first reflective portion 221 and a second reflective portion 222. The first reflective portion 221 and the second reflective portion 222 are sequentially located on the substrate 210. The second reflective portion 222 and the second mirror 230 have impurities. The active layer 240 is located between the first mirror 220 and the second mirror 230. The first reflective portion 221 is adapted to electrically isolate the active layer 240 from the substrate 210.

[0125] In some embodiments, the substrate 210 is the same as or similar to the substrate 110 in the Figure 1 illustrated embodiment.

[0126] In some embodiments, the second reflective portion 222 is the same as or similar to the second reflective portion 122 in the Figure 1 illustrated embodiment.

[0127] In some embodiments, the second mirror 230 is the same as or similar to the second mirror 130 in the Figure 1 illustrated embodiment.

[0128] In some embodiments, the active layer 240 is the same as or similar to the active layer 140 in the Figure 1 illustrated embodiment.

[0129] In some specific embodiments, the first reflection portion 221 includes: a first doping layer 221a having impurities of a second conductivity type.

[0130] The first doping layer 221a is adapted to form a reverse-biased junction (such as a reverse-biased PN junction) with an adjacent epitaxial layer to achieve an electrical insulation effect. Specifically, the first doping layer 221a is a p-type doping layer, and the first doping layer 221a and an adjacent n-type doping layer form an n-p junction.

[0131] In some specific examples, such as Figure 2 shown, the first doping layer 221a includes p-type impurities, and the first doping layer 221a and an adjacent n-type doping layer form an n-p junction, constituting a reverse-biased junction, thereby achieving electrical insulation between the first reflection portion 221 and the substrate 210, that is, electrical insulation between the resonant cavity and the substrate 210.

[0132] The thickness of the first reflection portion 221 is determined based on the wavelength of the light generated by the laser. The thickness of the first reflection portion 221 is determined based on the wavelength of the light generated by the laser to ensure stronger reflection coherence and facilitate the formation of a standing wave in the resonant cavity.

[0133] The first reflection portion 221 not only serves as part of the first mirror 220 to form a part of a reflective surface of the resonant cavity, but also serves as an insulating layer to achieve electrical insulation on the substrate side of the laser. Without the need to grow an additional epitaxial layer as an insulating layer, the overall thickness of the epitaxial growth can be reduced, which is beneficial to improving the epitaxial crystal quality, the resonant cavity quality, and the device yield.

[0134] In some embodiments of the present disclosure, the doping concentration of the first doping layer 221a is lower than the doping concentration of the second mirror 230. A low-doped first doping layer 221a (low-dop-p) is provided to form a reverse-biased junction, further enhancing the insulation effect. Among them, the doping concentration of the first doping layer 221a can be in the range of 1E16 atom / cm 3 to 1E17 atom / cm 3 range.

[0135] In some embodiments, the first reflection portion 221 further includes: a second doping layer 221b having impurities of a first conductivity type. Specifically, the second doping layer 221b is an n-type doping layer.

[0136] In some embodiments, such as Figure 2 shown, the second doping layer 221b is located between the first doping layer 221a and the substrate 210.

[0137] In some other embodiments, the second doping layer 221b is located between the first doping layer 221a and the second reflecting portion 222.

[0138] In other embodiments, the second doping layer 221b may be located between the first doping layer 221a and the substrate 210, and between the first doping layer 221a and the second reflecting portion 222. As long as the first doping layer 221a can form a reverse-biased junction with the adjacent epitaxial layer.

[0139] In some embodiments, such as Figure 2 shown, the laser further includes: a current spreading layer 224, the current spreading layer 224 is located between the first reflecting portion 221 and the second reflecting portion 222; the current spreading layer 224 has impurities of a first conductivity type.

[0140] In addition, in some embodiments, the first reflecting portion 221 has a plurality of the first doping layers 221a; the second doping layer 221b is also provided between the first doping layer 221a and the substrate 110.

[0141] In some other embodiments, the first reflecting portion 221 includes a plurality of first doping layers 221a and a plurality of second doping layers 221b, and the plurality of first doping layers 221a and the plurality of second doping layers 221b are arranged alternately to form a plurality of reverse-biased junctions, which is beneficial to further enhancing the electrical insulation effect.

[0142] In some embodiments of the present disclosure, the doping concentration of the second doping layer 221b is lower than the doping concentration of the second reflecting portion 222; the doping concentration of at least some of the second doping layers 221b is lower than the doping concentration of the second mirror 230.

[0143] The first doping layer 221a may form a reverse-biased junction with an adjacent epitaxial layer of the first conductivity type in the laser; the first doping layer 221a may also form a reverse-biased junction with other epitaxial layers in the first reflecting portion 221.

[0144] Such as Figure 2 shown in some embodiments, the first mirror 220 further includes a third reflecting portion 223. The third reflecting portion 223 is located between the first reflecting portion 221 and the substrate 210. Exemplarily, the third reflecting portion 223 includes an intrinsic layer. Specifically, all materials of the third reflecting portion 223 are intrinsic materials, the third reflecting portion 223 is not doped, the third reflecting portion 223 does not include impurities, and in the third reflecting portion 223, both the high refractive index film and the low refractive index film are intrinsic layers. The undoped intrinsic material has low light absorption, thereby reducing light loss and improving the optical power of the laser.

[0145] In some other embodiments, the third reflecting portion 223 includes impurities of a first conductivity type. Specifically, the doping concentration of the third reflecting portion 223 is not higher than that of the second reflecting portion 222. Preferably, the doping concentration of the third reflecting portion 223 is lower than that of the second reflecting portion 222. The lower doping concentration of the third reflecting portion 223 can reduce the absorption of light and improve the optical power of the laser.

[0146] It should be noted that the n-type doped layer forming a reverse-biased junction with the first doped layer 221a may include any one or more of the following: the n-type doped layer between the first doped layer 221a and the substrate 210, the n-type doped layer between the first doped layer 221a and the second reflecting portion 222, the n-type doped substrate 210, the n-type doped second reflecting portion 222, the n-type doped third reflecting portion 223, or the n-type doped current diffusion layer 224.

[0147] It should also be noted that in the foregoing embodiments, in the first reflecting portion 221, doped layers of different conductivity types are in direct contact to form a reverse-biased PN junction. However, in other embodiments of the present disclosure, electrical insulation can also be achieved through a reverse-biased PIN junction.

[0148] Reference Figure 3 , showing a schematic cross-sectional structure diagram of a third embodiment of the laser of the present disclosure.

[0149] As Figure 3 shown, the laser includes a substrate 310, a first mirror 320, a second mirror 330, and an active layer 340.

[0150] Among them, the substrate 310 has impurities of a first conductivity type. The first mirror 320 and the second mirror 330 are sequentially stacked on one side of the substrate 310. Among them, the first mirror 320 includes: a first reflecting portion 321 and a second reflecting portion 322. The first reflecting portion 321 and the second reflecting portion 322 are sequentially located on the substrate 310. The second reflecting portion 322 and the second mirror 330 have impurities. The active layer 340 is located between the first mirror 320 and the second mirror 330. The first reflecting portion 321 is adapted to electrically isolate the active layer 340 from the substrate 310.

[0151] In some embodiments, the substrate 310 is the same as or similar to the substrate 110 in the Figure 1 embodiment shown.

[0152] In some embodiments, the second reflecting portion 322 is the same as or similar to the second reflecting portion 122 in the Figure 1 embodiment shown.

[0153] In some embodiments, the second reflector 330 is the same as or similar to Figure 1 the second reflector 130 in the illustrated embodiment.

[0154] In some embodiments, the active layer 340 is the same as or similar to Figure 1 the active layer 140 in the illustrated embodiment.

[0155] In some specific embodiments, the first reflective portion 321 includes: a first doped layer 321a, and the first doped layer 321a has impurities of a second conductivity type.

[0156] The first reflective portion 321 further includes: an intrinsic layer 321c. Specifically, all materials of the intrinsic layer 321c are intrinsic materials, the intrinsic layer 321c is not doped, and the intrinsic layer 321c does not include impurities.

[0157] The first doped layer 321a, the intrinsic layer 321c, and the epitaxial layer adjacent to the intrinsic layer 321c and having impurities of a first conductivity type form a p-i-n junction. By forming a reverse-biased junction, electrical insulation between the first reflective portion 321 and the substrate 310 is achieved, that is, electrical insulation between the resonant cavity and the substrate 310.

[0158] It should be noted that the p-i-n junction can be in the direction where the first doped layer 321a points to the substrate 310, or in the direction where the first doped layer 321a points to the second reflective portion 322.

[0159] In some embodiments, the intrinsic layer 321c is located on a side of the first doped layer 321a away from the substrate 310. The first doped layer 321a, the intrinsic layer 321c, and the epitaxial layer adjacent to the side of the intrinsic layer 321c facing away from the substrate and having impurities of a first conductivity type form a p-i-n junction.

[0160] In some other embodiments, the intrinsic layer 321c is located on a side of the first doped layer 321a facing the substrate 310. The first doped layer 321a, the intrinsic layer 321c, and the epitaxial layer adjacent to the side of the intrinsic layer 321c facing the substrate and having impurities of a first conductivity type form a p-i-n junction.

[0161] In some other embodiments, the intrinsic layer 321c is located on a side of the first doped layer 321a away from the substrate 310 and on a side of the first doped layer 321a facing the substrate 310. The intrinsic layer 321c and the first doped layer 321a form an i-p-i junction and form an n-i-p-i-n junction with the adjacent epitaxial layer having impurities of a first conductivity type.

[0162] In some embodiments, the first mirror 320 further includes a third reflecting portion 323. The third reflecting portion 323 is located between the first reflecting portion 321 and the substrate 310. The third reflecting portion 323 may be the same as or similar to Figure 1 the third reflecting portion 123 in the illustrated embodiment.

[0163] In some embodiments, the laser or the first mirror 320 further includes a current spreading layer (not labeled in the figure). The current spreading layer is located between the first reflecting portion 221 and the second reflecting portion 222. In a specific implementation, the current spreading layer is the same as or similar to Figure 1 the current spreading layer 124 in the illustrated embodiment.

[0164] It should be noted that the n-type doped layer that forms a reverse-biased PIN junction with the first doped layer 321a and the intrinsic layer 321c may include any one or more of the following: the n-type doped layer between the intrinsic layer 321c and the substrate 310, the n-type doped layer between the intrinsic layer 321c and the second reflecting portion 322, the n-type doped substrate 310, the n-type doped second reflecting portion 322, the n-type doped third reflecting portion 323, or the n-type doped current spreading layer.

[0165] Correspondingly, the present disclosure also provides a laser array.

[0166] Referring to Figure 1 , a schematic cross-sectional structure diagram of a first embodiment of the laser array of the present disclosure is shown.

[0167] As Figure 1 shown, the laser array includes a plurality of lasers, and each laser includes: a substrate 110 having impurities of a first conductivity type; a first mirror 120 and a second mirror 130, the first mirror 120 and the second mirror 130 are sequentially stacked on one side of the substrate 110, wherein the first mirror 120 includes: a first reflecting portion 321 and a second reflecting portion 122, the first reflecting portion 321 and the second reflecting portion 122 are sequentially located on the substrate 110, and the second reflecting portion 122 and the second mirror 130 have impurities; an active layer 140, the active layer 140 is located between the first mirror 120 and the second mirror 130, and the first reflecting portion 321 is adapted to electrically isolate the active layer 140 from the substrate 110.

[0168] In some specific embodiments of the present disclosure, the laser is the laser of the present disclosure. For the specific technical solutions of the laser, reference may be made to the specific embodiments of the foregoing laser, and the present disclosure will not elaborate herein.

[0169] In some embodiments of the present disclosure, the substrates 110 of at least some of the lasers are integrally connected. Among the multiple lasers of the laser array, at least some of the lasers are integrated on the same substrate 110. In some specific embodiments, the substrates 110 of the multiple lasers of the laser array are all integrally connected, and the multiple lasers of the laser array are all integrated on the same substrate 110.

[0170] As Figure 1 shown, in some embodiments, the laser further includes: a third reflecting portion 123, and the third reflecting portion 123 is located between the first reflecting portion 321 and the substrate 110; the third reflecting portions 123 of at least some of the lasers are integrally connected.

[0171] Specifically, among the multiple lasers of the laser array, at least some of the lasers all have a third reflecting portion 123, and the third reflecting portions 123 of different lasers are continuously connected. In some specific embodiments, the multiple lasers of the laser array all have a third reflecting portion 123, and the third reflecting portions 123 of the multiple lasers are all integrally connected.

[0172] As Figure 1 shown, in some embodiments, the laser array further includes: an isolation structure 160, the isolation structure 160 is located between adjacent lasers, and the isolation structure 160 extends from the surface of the first reflecting portion 121 on the side away from the substrate 110 towards the substrate 110.

[0173] The isolation structure 160 is used to achieve electrical insulation between adjacent lasers.

[0174] In specific implementation, part of the second mirror 130, the active layer 140, and the second reflecting portion 122 are etched to form the light-emitting mesa of multiple laser resonators. Part of the first reflecting portion 121 is exposed between the light-emitting mesas of adjacent lasers, and part of the first reflecting portion 121 is etched to form the isolation structure 160. As Figure 1 shown, the isolation structure 160 is located in the first reflecting portion 121 at least partially away from the substrate 110.

[0175] In some specific embodiments, the surface of the isolation structure 160 can be coated with a dielectric material, such as silicon oxide, silicon nitride, or silicon oxynitride, etc.

[0176] In some other embodiments, after the light-emitting mesas of multiple laser resonators are formed, part of the first reflecting portion 121 is exposed between the light-emitting mesas of adjacent lasers, and a dielectric material is ion-implanted into part of the first reflecting portion 121 to form an isolation structure 160 with an insulating effect.

[0177] In some embodiments of the present disclosure, the laser further includes a current diffusion layer 124, and the current diffusion layer 124 is located between the first reflection portion 121 and the second reflection portion 122. A part of the current diffusion layer 124 is exposed between the light-emitting surfaces of adjacent lasers, and the isolation structure 160 extends from the surface of the current diffusion layer 124 away from the substrate 110 into the first reflection portion 321. In the thickness direction, the isolation structure 160 penetrates through the current diffusion layer 124 to insulate the current diffusion layers 124 of adjacent lasers from each other.

[0178] In some embodiments, the isolation structure 160 penetrates through at least a part of the thickness of the first reflection portion 121.

[0179] The distance between the surface of the first reflection portion 121 facing away from the substrate 110 and the substrate 110 is not greater than the distance between the end of the isolation structure 160 facing away from the substrate 110 and the substrate 110; the end of the isolation structure 160 facing the substrate 110 is at least located within the first reflection portion 121. As Figure 1 In some specific embodiments shown, the isolation structure 160 extends in the thickness direction, and the end of the isolation structure 160 facing the substrate 110 is located within the first reflection portion 121.

[0180] It should be noted that in other embodiments of the present disclosure, the isolation structure 160 may also penetrate through the first reflection portion 121, and the distance between the surface of the first reflection portion 121 facing the substrate 110 and the substrate 110 is not less than the distance between the end of the isolation structure 160 facing the substrate 110 and the substrate 110.

[0181] In some specific implementations, the first reflection portion 121 includes an intrinsic layer; the isolation structure 160 penetrates through a part of the thickness of the first reflection portion 121. The electrical insulation on the substrate side is achieved by using the insulation property of the intrinsic material, and the insulation performance of the intrinsic layer is stable. Therefore, the isolation structure penetrating through a part of the thickness of the first reflection portion 121 can achieve electrical isolation between adjacent lasers.

[0182] It should also be noted that as Figure 2 shown, in other embodiments of the present disclosure, the first reflection portion 221 includes a first doped layer 221a, and the first doped layer 221a has impurities of a second conductivity type; the isolation structure 260 penetrates through the entire thickness of the first reflection portion 221. The electrical insulation on the substrate side is achieved by using a reverse-biased junction, which can further improve the quality of the epitaxial material. With the isolation structure 260 penetrating through the entire thickness, better electrical isolation between adjacent lasers can be ensured.

[0183] In addition, the present disclosure also provides a lidar.

[0184] The lidar includes: a light source adapted to generate detection light, and the light source includes: at least one laser. Referring to the combination Figure 1 , the laser includes: a substrate 110 having impurities of a first conductivity type; a first mirror 120 and a second mirror 130, the first mirror 120 and the second mirror 130 are sequentially stacked on one side of the substrate 110. Wherein, the first mirror 120 includes: a first reflection portion 321 and a second reflection portion 122, the first reflection portion 321 and the second reflection portion 122 are sequentially located on the substrate 110, and the second reflection portion 122 and the second mirror 130 have impurities; an active layer 140, the active layer 140 is located between the first mirror 120 and the second mirror 130, and the first reflection portion 321 is adapted to electrically isolate the active layer 140 from the substrate 110; a detector adapted to receive the echo light formed by the detection light reflected by an object.

[0185] In some embodiments of the present disclosure, the light source of the lidar includes the laser of the present disclosure. For the specific technical solution of the laser, refer to the specific embodiments of the foregoing laser, and the present disclosure will not elaborate herein.

[0186] In summary, the substrate has impurities of a first conductivity type; the first mirror includes a first reflection portion that electrically isolates the active layer from the substrate. Compared with an insulating substrate, a conductive substrate has better quality and a lower defect density. Therefore, forming a resonant cavity on the conductive substrate can effectively improve the quality of the epitaxial crystal, improve the device yield and reliability; treating the first reflection portion close to the substrate as an insulating layer can achieve electrical insulation on the substrate side without additionally increasing the thickness of the epitaxial layer, which can reduce the epitaxial time and is beneficial to improving the quality of the epitaxial crystal and the device yield.

[0187] Moreover, the first reflection portion may include an intrinsic layer, or the first reflection portion may include a first doped layer having impurities of a second conductivity type. Using an intrinsic material to improve the electrical insulation performance on the substrate side, or using a reverse-biased junction to improve the electrical insulation performance on the substrate side can effectively reduce the overall doping concentration of the first mirror and effectively reduce the optical loss.

[0188] In addition, the first mirror further includes a third reflection portion located between the first reflection portion and the substrate, and the third reflection portion includes an intrinsic layer or impurities of a first conductivity type. The setting of the third reflection portion can effectively improve the reflectivity of the first mirror and improve the beam quality of the laser.

[0189] In addition, the first reflector and the second reflector are distributed Bragg reflectors. By using part of the film layer of the distributed Bragg reflector as an insulating layer treatment, electrical insulation on the substrate side can be achieved without additionally increasing the thickness of the epitaxial layer, which can effectively reduce the thickness of the epitaxial growth material, shorten the epitaxial growth time, and is beneficial to cost reduction and improvement of the epitaxial crystal quality.

[0190] Moreover, the laser array further includes: an isolation structure located between adjacent lasers, and the isolation structure extends from the surface of the first reflection portion away from the substrate side towards the substrate. The setting of the isolation structure can further improve the electrical insulation performance of adjacent lasers.

Claims

1. A laser, characterized in that, Comprising: A substrate having impurities of a first conductivity type; A first mirror and a second mirror, the first mirror and the second mirror being stacked in sequence on one side of the substrate, wherein the first mirror includes: a first reflection portion and a second reflection portion, the first reflection portion and the second reflection portion are located on the substrate in sequence, and the second reflection portion and the second mirror have impurities; An active layer located between the first mirror and the second mirror, and the first reflection portion is adapted to electrically isolate the active layer from the substrate.

2. The laser according to claim 1, wherein, The thickness of the first reflection portion is determined based on the wavelength of the light generated by the laser.

3. The laser according to claim 1, characterized in that, The first reflection portion includes: a first doped layer having impurities of a second conductivity type.

4. The laser according to claim 3, characterized in that, The first reflection portion further includes: a second doped layer having impurities of a first conductivity type, and the second doped layer is located at at least one of the following positions: Between the first doped layer and the substrate; and Between the first doped layer and the second reflection portion.

5. The laser according to claim 3, characterized in that, The first reflection portion further includes: an intrinsic layer located at at least one of the following positions: On the side of the first doped layer away from the substrate; On the side of the first doped layer facing the substrate.

6. The laser according to claim 1, characterized in that, The first mirror further includes: a current diffusion layer located between the first reflection portion and the second reflection portion.

7. The laser according to claim 1, characterized in that, Further comprising: A current diffusion layer located between the first reflection portion and the second reflection portion.

8. The laser according to claim 6 or 7, characterized in that, The current diffusion layer has impurities of a first conductivity type, and the doping concentration of the current diffusion layer is greater than the doping concentration of the second reflection portion.

9. The laser according to claim 1, wherein, The first reflection portion includes: an intrinsic layer.

10. The laser according to claim 1, characterized in that, The first mirror further includes: a third reflection portion located between the first reflection portion and the substrate.

11. The laser according to claim 10, characterized in that, The third reflection portion includes an intrinsic layer; or The third reflection portion has impurities of a first conductivity type.

12. The laser according to claim 10, characterized in that, The doping concentration of the third reflection portion is not higher than the doping concentration of the second reflection portion.

13. The laser according to claim 1, characterized in that, The direction of the first mirror pointing to the second mirror is consistent with the laser emission direction.

14. The laser according to claim 1 or 13, characterized in that, The first mirror and the second mirror are distributed Bragg reflectors.

15. The laser according to claim 1, characterized in that, The first conductivity type is n-type.

16. The laser according to claim 1, characterized in that, Further comprising: A first electrode; A second electrode located on the side of the second mirror away from the active layer.

17. The laser according to claim 16, wherein, Further comprising: A current diffusion layer located between the first reflection portion and the second reflection portion; The second reflection portion exposes a part of the current diffusion layer, and the first electrode is located on the part of the current diffusion layer exposed by the second reflection portion.

18. A laser array, characterized in that, Comprising: Multiple lasers, the lasers comprising: a substrate having impurities of a first conductivity type; a first mirror and a second mirror, the first mirror and the second mirror being sequentially stacked on one side of the substrate, wherein the first mirror includes: a first reflective portion and a second reflective portion, the first reflective portion and the second reflective portion are sequentially located on the substrate, and the second reflective portion and the second mirror have impurities; an active layer located between the first mirror and the second mirror, and the first reflective portion is adapted to electrically isolate the active layer from the substrate.

19. The laser array according to claim 18, wherein Further comprising: An isolation structure located between adjacent lasers, the isolation structure extending from the surface of the first reflective portion away from the substrate side towards the substrate.

20. The laser array according to claim 19, wherein The laser further comprises: a current diffusion layer located between the first reflective portion and the second reflective portion; The isolation structure extends from the surface of the current diffusion layer away from the substrate side into the first reflective portion.

21. The laser array according to claim 19, characterized in that, The first reflective portion includes: an intrinsic layer; The isolation structure passes through at least a partial thickness of the first reflective portion.

22. The laser array according to claim 19, wherein The first reflective portion includes: a first doped layer having impurities of a second conductivity type; The isolation structure passes through the entire thickness of the first reflective portion.

23. The laser array according to claim 18, wherein The substrates of at least a portion of the lasers are integrally connected.

24. The laser array according to claim 18, wherein The laser further comprises: a third reflective portion located between the first reflective portion and the substrate; The third reflective portions of at least a portion of the lasers are integrally connected.

25. A lidar, characterized in that, Comprising: A light source adapted to generate detection light, the light source including: at least one laser, the laser including: a substrate having impurities of a first conductivity type; a first mirror and a second mirror, the first mirror and the second mirror being sequentially stacked on one side of the substrate, wherein the first mirror includes: a first reflective portion and a second reflective portion, the first reflective portion and the second reflective portion are sequentially located on the substrate, and the second reflective portion and the second mirror have impurities; an active layer located between the first mirror and the second mirror, and the first reflective portion is adapted to electrically isolate the active layer from the substrate; A detector adapted to receive the echo light formed by the reflection of the detection light by an object.

Images