Laser array and forming method therefor and laser radar

Abstract

A laser array and a forming method therefor and a laser radar (L0). The laser array comprises: a light-emitting cavity, the light-emitting cavity comprising an epitaxial layer (102); a first electrode (112), the first electrode (112) being at least partially located on a first surface of the epitaxial layer (102); a plurality of second electrodes (128), the plurality of second electrodes (128) being at least partially located on a second surface of the epitaxial layer (102); and a first isolation structure (122), the first isolation structure (122) being used for providing electrical isolation between at least some adjacent second electrodes (128) among the plurality of second electrodes (128). The laser radar (L0) comprises a laser transmitter (L01), and the laser transmitter (L01) comprises a laser array. By arranging the second electrodes (128) on the second surface of the epitaxial layer (102), the second electrodes (128) having a larger size can be designed, such that the light-emitting area of the light-emitting region of the laser array can be increased, thereby improving the detection performance of the laser radar (L0).

Description

Laser array and forming method thereof, laser radar Technical Field

[0001] The present disclosure relates to the field of laser radar technology, and in particular to a laser array and a method for forming the same, and a laser radar. Background Art

[0002] LiDAR is an active remote sensing device that uses lasers as its light source and photoelectric detection technology. It has a wide range of applications in scenarios such as autonomous driving. Lasers can be of various types, such as vertical-cavity surface-emitting lasers (VCSELs) and distributed feedback lasers.

[0003] Multiple lasers can form a laser array. To achieve light emission control of the laser array, the laser array needs to be two-dimensionally addressable, for example, selecting and activating specific lasers in the two-dimensional dimensions of the laser array (for example, the dimensions of rows and columns) to make specific lasers in the laser array emit light. Summary of the Invention

[0004] The embodiments of the present disclosure provide a laser array and a method for forming the same, and a laser radar, which can increase the light-emitting area of ​​the light-emitting region of the laser array, thereby improving the detection performance of the laser radar.

[0005] First, the present disclosure provides a laser array, comprising:

[0006] a light-emitting cavity, the light-emitting cavity comprising an epitaxial layer;

[0007] a first electrode, the first electrode being at least partially located on a first surface of the epitaxial layer;

[0008] a plurality of second electrodes, wherein the plurality of second electrodes are at least partially located on the second surface of the epitaxial layer;

[0009] A first isolation structure is provided, wherein the first isolation structure is used to provide electrical isolation between at least some adjacent second electrodes in the plurality of second electrodes.

[0010] Optionally, the first isolation structure includes:

[0011] a first trench, wherein the first trench is located between at least a portion of the adjacent second electrodes and penetrates at least one layer of the epitaxial layer;

[0012] The first passivation layer is at least partially located on the inner wall of the first trench and extends along the inner wall of the first trench to the second surface of the epitaxial layer.

[0013] Optionally, the laser array further includes:

[0014] a through hole passing through the epitaxial layer;

[0015] The first electrode extends through the through hole to the second surface of the epitaxial layer.

[0016] Optionally, the first passivation layer at least partially extends to the inner wall of the through hole;

[0017] The laser array further comprises:

[0018] The second isolation structure includes a portion of the first passivation layer extending to the inner wall of the through hole.

[0019] Optionally, the laser array further includes:

[0020] a second trench, wherein the second trench is located between the through hole and at least part of the second electrodes, and the second trench penetrates at least one layer of the epitaxial layer;

[0021] The first passivation layer is at least partially located on an inner wall of the second trench and extends along the inner wall of the second trench to the second surface of the epitaxial layer.

[0022] Optionally, the first electrode includes:

[0023] a first contact layer, the first contact layer being located on a first surface of the epitaxial layer;

[0024] The first pad is electrically connected to the first contact layer.

[0025] Optionally, the laser array further includes:

[0026] a third trench, wherein the third trench penetrates at least one layer of the epitaxial layer;

[0027] The first pad extends into the third trench.

[0028] Optionally, the laser array further includes:

[0029] A second passivation layer is at least partially located on an inner wall of the third trench and extends along the inner wall of the third trench to the first surface of the epitaxial layer and a top of the first contact layer.

[0030] Optionally, the third groove at least partially overlaps with a projection of the first groove in a direction perpendicular to the first surface.

[0031] Optionally, projections of the third groove and the first groove in a direction perpendicular to the first surface do not overlap with each other.

[0032] Optionally, the second electrode includes:

[0033] a second contact layer, the second contact layer being located on the second surface of the epitaxial layer;

[0034] A second pad is electrically connected to the second contact layer, and the second pad is at least partially located on the second surface of the epitaxial layer.

[0035] Optionally, the laser array further includes:

[0036] A transparent substrate is located on the first surface side of the epitaxial layer and covers the first electrode and the first surface of the epitaxial layer.

[0037] Optionally, the laser array further includes:

[0038] An adhesion layer is located between the first surface of the epitaxial layer and the transparent substrate.

[0039] Optionally, the light-emitting cavity further includes an oxide layer.

[0040] Secondly, the present disclosure also provides a method for forming a laser array, comprising:

[0041] providing a substrate;

[0042] forming an epitaxial layer by epitaxial growth on the substrate, wherein the epitaxial layer has a first surface and a second surface, wherein the second surface is located between the substrate and the first surface;

[0043] forming a first electrode at least partially located on the first surface of the epitaxial layer;

[0044] removing the substrate;

[0045] forming a plurality of second electrodes at least partially located on the second surface of the epitaxial layer;

[0046] A first isolation structure is formed to provide electrical isolation between at least some adjacent second electrodes in the plurality of second electrodes.

[0047] Optionally, forming a first electrode at least partially located on the first surface of the epitaxial layer includes:

[0048] A first contact layer is formed in a partial region of the first surface of the epitaxial layer.

[0049] Optionally, after forming the first electrode at least partially located on the first surface of the epitaxial layer and before removing the substrate, the method further includes:

[0050] forming a third trench penetrating at least one layer of the epitaxial layer;

[0051] performing oxidation treatment on at least one epitaxial layer on both sides of the third trench to form an oxide layer;

[0052] A second passivation layer is formed on a portion of the first surface of the epitaxial layer and on a top of the first contact layer, and the second passivation layer extends to an inner wall of the third trench.

[0053] Optionally, the forming of the first electrode at least partially located on the first surface of the epitaxial layer further includes:

[0054] A first pad electrically connected to the first contact layer is formed on the first surface of the epitaxial layer, and the first pad extends into the third trench.

[0055] Optionally, after removing the substrate and before forming a plurality of second electrodes at least partially located on the second surface of the epitaxial layer, the method further includes:

[0056] providing a transparent substrate and an adhesive layer;

[0057] bonding the bottom of the adhesion layer to the first surface side of the epitaxial layer and at least partially covering the first electrode and the first surface of the epitaxial layer;

[0058] The transparent substrate is bonded on top of the adhesion layer.

[0059] Optionally, forming a plurality of second electrodes at least partially located on the second surface of the epitaxial layer includes:

[0060] A second contact layer is formed in a partial region of the second surface of the epitaxial layer.

[0061] Optionally, forming a first isolation structure for providing electrical isolation between at least some adjacent second electrodes among the plurality of second electrodes includes:

[0062] forming a first trench between at least portions of adjacent second contact layers, wherein the first trench penetrates at least one layer of the epitaxial layer;

[0063] A first passivation layer is formed on an inner wall of the first trench, and the first passivation layer extends along the inner wall of the first trench to the second surface of the epitaxial layer.

[0064] Optionally, the method for forming the laser array further includes:

[0065] forming a through hole through the epitaxial layer;

[0066] The forming of the first electrode at least partially located on the first surface of the epitaxial layer further includes:

[0067] extending the first electrode along the through hole to the second surface;

[0068] The forming of a plurality of second electrodes at least partially located on the second surface of the epitaxial layer further comprises:

[0069] A second pad electrically connected to the second contact layer is formed.

[0070] Optionally, before extending the first electrode along the through hole to the second surface and forming a second pad electrically connected to the second contact layer, the method further includes:

[0071] The first passivation layer is formed on the inner wall of the through hole.

[0072] Optionally, before extending the first electrode along the through hole to the second surface and forming a second pad electrically connected to the second contact layer, the method further includes:

[0073] forming a second trench between the through hole and a portion of the second electrodes among the plurality of second electrodes, wherein the second trench penetrates at least one layer of the epitaxial layer;

[0074] The first passivation layer is formed in the second trench, and the first passivation layer extends along the inner wall of the second trench to the second surface of the epitaxial layer.

[0075] Optionally, the third groove at least partially overlaps with a projection of the first groove in a direction perpendicular to the first surface.

[0076] Optionally, projections of the third groove and the first groove in a direction perpendicular to the first surface do not overlap with each other.

[0077] Optionally, the substrate is removed by at least one of the following methods:

[0078] Mechanical grinding process;

[0079] Chemical mechanical planarization process;

[0080] Wet etching process;

[0081] Back grinding process.

[0082] Accordingly, the present disclosure further provides a laser radar, comprising:

[0083] A laser transmitter, configured to emit a light beam into an environment, wherein the laser transmitter comprises a laser array as described in any of the preceding examples;

[0084] a detector, configured to receive an echo of the light beam after it is reflected by one or more objects in the environment and generate a signal;

[0085] A processor is coupled to the detector and is configured to receive and process the signal to obtain at least one of the distance and reflectivity of the object.

[0086] Using the laser array disclosed in the present invention, the laser array may include a light-emitting cavity. The light-emitting cavity may include an epitaxial layer. The epitaxial layer has a first surface and a second surface, wherein the first electrode may be at least partially located on the first surface of the epitaxial layer. By arranging a plurality of second electrodes at least partially on the second surface of the epitaxial layer, and forming a first isolation structure on the second surface of the epitaxial layer for providing electrical isolation between at least partially adjacent second electrodes among the plurality of second electrodes, the non-light-emitting area of ​​the first surface of the epitaxial layer can be reduced, and the light-emitting area of ​​the laser array can be increased. By arranging the second electrode on the second surface of the epitaxial layer, a second electrode with a larger size can be designed, which can reduce the resistance of the second electrode, reduce the impact of the resistance, facilitate current injection into each light-emitting cavity, and improve the detection performance of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] FIG1 is a schematic diagram showing a structure of an example of a laser array consistent with some embodiments of the present disclosure;

[0088] FIG2 is a schematic diagram showing a structure of an example of a laser array consistent with some embodiments of the present disclosure;

[0089] FIG3 is a schematic diagram showing a structure of an example of a laser array consistent with some embodiments of the present disclosure;

[0090] 4 to 15 are schematic structural diagrams corresponding to steps in a method for forming an example of a laser array consistent with some embodiments of the present disclosure;

[0091] 16 to 24 are schematic structural diagrams corresponding to steps in another example method for forming a laser array consistent with some embodiments of the present disclosure;

[0092] FIG25 shows a schematic structural diagram of an example of a lidar consistent with some embodiments of the present disclosure. DETAILED DESCRIPTION

[0093] In the following, some embodiments are described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be considered as non-restrictive in nature.

[0094] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. 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 indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0095] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "according to," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections, electrical connections, or connections capable of mutual communication; they may refer to direct connections or indirect connections through an intermediate medium; they may refer to internal communication between two components or interactions between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0096] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0097] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0098] The following describes embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0099] In the light-emitting scheme of vertical cavity surface emitting laser arrays, one design scheme is to interconnect the anodes of some lasers in a two-dimensional VCSEL array, while isolating the cathodes. Alternatively, the cathodes of some lasers are interconnected, while the anodes are isolated. For example, the anodes of lasers in the same row of the array are interconnected, while the cathodes are isolated, while the anodes of lasers in the same column are isolated, while the cathodes are connected. By selectively connecting specific anode electrodes and specific cathode electrodes, the VCSEL array can be two-dimensionally addressable.

[0100] In some embodiments, two-dimensional addressability of a VCSEL array can include enabling independent control of at least some of the lasers in the two-dimensional VCSEL array.

[0101] Another design scheme is that the lasers in the VCSEL array share a common anode and the cathodes are isolated from each other. The cathode of each laser is connected to the corresponding switch on the driving module. By selectively turning on the corresponding switch, independent control and two-dimensional addressability of at least some of the lasers in the VCSEL two-dimensional array can be achieved.

[0102] The manufacturing difficulty of a two-dimensional addressable VCSEL array lies in the need to maintain isolation between different channels to reduce or avoid crosstalk between lasers. In current manufacturing processes, both the anode and cathode electrodes are located on the light-emitting surface of the light-emitting area, which occupies part of the surface area. Furthermore, to achieve isolation between the different lasers, a trench structure must be etched into the surface, which also occupies part of the surface area.

[0103] In order to enable those skilled in the art to better understand the prior art, the structure of a laser array is described below as an example.

[0104] Referring to the structural schematic diagram of an example of a laser array shown in FIG1 , as shown in FIG1 , the laser array includes a plurality of semiconductor lasers, the plurality of semiconductor lasers share a common substrate 10 , and each semiconductor laser further includes an epitaxial layer located above the substrate 10 .

[0105] A semiconductor laser includes an n-type contact layer 11 located above the substrate 10, a cathode electrode 12 and an epitaxial layer 13 located on the n-type contact layer 11, an anode electrode 14 located on the epitaxial layer 13, and a p-type contact layer 15 electrically connected to the anode electrode 14.

[0106] In some examples, a trench is formed in the epitaxial layer 13 , and the p-type contact layer 15 extends into the trench. After the trench is formed, the active area can be oxidized along the lateral portion of the inner wall of the trench to form an oxide layer.

[0107] The laser array shown in FIG1 can adopt the method of emitting light from the front side (for example, the upper side in FIG1 ). Since the cathode electrode 12 and the anode electrode 14 are also located on the front side of the semiconductor laser, they already occupy part of the area of ​​the light-emitting surface. In order to prevent the current of the semiconductor laser from propagating in the lateral direction as shown in FIG1 , for example, it is necessary to electrically isolate adjacent semiconductor lasers.

[0108] For example, still referring to FIG. 1 , the laser array further includes an isolation structure 16 for achieving electrical isolation between semiconductor lasers.

[0109] When etching the deep trench structure to form the isolation structure 16, it is also necessary to reserve space for the cathode electrode (as shown by the circle in FIG1 ). Therefore, the isolation structure 16 occupies a larger area, which reduces the duty cycle of the light-emitting surface on the light-emitting channel.

[0110] An embodiment of the present disclosure provides a laser array, in which a first electrode can be at least partially located on the first surface of the epitaxial layer. By arranging a plurality of second electrodes at least partially on the second surface of the epitaxial layer, and forming a first isolation structure on the second surface of the epitaxial layer for providing electrical isolation between at least partially adjacent second electrodes in the plurality of second electrodes, the non-luminous area of ​​the first surface of the epitaxial layer can be reduced, and the luminous area of ​​the laser array can be increased. In addition, by arranging the second electrode on the second surface of the epitaxial layer, a second electrode with a larger size can be designed, which can reduce the resistance of the second electrode, reduce the impact of the resistance, facilitate current injection into each light-emitting cavity, and improve the detection performance of the laser radar.

[0111] In order to enable those skilled in the art to more clearly understand and implement the laser array in the present disclosure, the laser array in the embodiment of the present disclosure is described below with reference to the accompanying drawings.

[0112] In some embodiments, different isolation structures may be used to achieve electrical isolation between at least some adjacent second electrodes among the plurality of second electrodes.

[0113] As an example, the first surface and the second surface of the epitaxial layer may be etched separately to form an isolation structure to achieve cathode isolation of each light-emitting cavity, thereby increasing the duty cycle of the light-emitting surface.

[0114] For example, referring to the structural diagram of a laser array example in an embodiment of the present disclosure shown in FIG2 , the laser array may include a vertical cavity surface emitting laser (VCSEL) array.

[0115] In some examples, as shown in FIG2 , the laser array may include: a light-emitting cavity, which may include an epitaxial layer 102; a first electrode 112, which may be at least partially located on the first surface of the epitaxial layer 102; a plurality of second electrodes 128, which may be at least partially located on the second surface of the epitaxial layer 102; and a first isolation structure 122, which may be used to provide electrical isolation between at least partially adjacent second electrodes in the plurality of second electrodes 128.

[0116] In some examples, epitaxial layer 102 may include one or more n-doped epitaxial layers, wherein the n-doped epitaxial layers may include n-doped distributed Bragg reflector (nDBR) layers and / or n+ doped buffer layers.

[0117] In some examples, the nDBR layer can include alternating layers of n-doped gallium arsenide (GaAs) and n-doped aluminum gallium arsenide (AlGaAs).

[0118] In some examples, the n+ doped buffer layer may include only GaAs and may be thicker than each of the alternating nDBR layers, thereby reducing the difficulty of etching the n+ doped buffer layer.

[0119] It should be noted that in some embodiments of the present disclosure, the epitaxial layer 102 includes an nDBR layer for illustration. In other embodiments of the present disclosure, the epitaxial layer 102 may further include an n+ doped buffer layer.

[0120] In some examples, the epitaxial layer 102 may include one or more p-doped epitaxial layers formed on an n-doped epitaxial layer, wherein the p-doped epitaxial layer may be a p-doped distributed Bragg reflector (pDBR) layer.

[0121] In some embodiments, the p-doped epitaxial layer and the n-doped epitaxial layer may form a semiconductor mirror.

[0122] In some examples, the epitaxial layer 102 may include one or more active layers including one or more quantum well (QW) layers.

[0123] In some examples, the epitaxial layer 102 may have a first surface and a second surface, wherein the second surface is a surface close to the second electrode 128, and the first surface is a surface close to the first electrode 112. In other examples, the first surface may be a surface close to the second electrode 128, and the second surface may be a surface close to the first electrode 112.

[0124] In some embodiments, the first surface of the epitaxial layer 102 may be used as a light emitting surface, that is, the laser may be emitted from the first surface side.

[0125] In some other embodiments, the second surface of the epitaxial layer 102 can be used as a light emitting surface, that is, the laser light can be emitted from the second surface side.

[0126] In some embodiments, the first electrode 112 may include a first contact layer 104 and a first pad 110 , wherein the first contact layer 104 may be located on the first surface of the epitaxial layer 102 , and the first pad 110 may be electrically connected to the first contact layer 104 .

[0127] In some embodiments, the first contact layer 104 may serve as a portion of the semiconductor device connected to an external circuit, has conductive properties, and can form an ohmic contact with the semiconductor material.

[0128] In some examples, the first contact layer 104 may be made of metal (eg, metals with good electrical conductivity, such as gold, silver, and copper) or highly doped semiconductor materials.

[0129] In some examples, the first contact layer 104 may be a p-type contact layer.

[0130] In some other examples, the first contact layer 104 may be an n-type contact layer.

[0131] In some examples, the first pad 110 may be composed of metal or a highly doped semiconductor material.

[0132] In some examples of the present disclosure, the first pad 110 and the first contact layer 104 may serve as a first electrode 112 of the laser array. Through the first electrode 112 , the laser array can be connected to an external circuit.

[0133] In some examples, the first electrode 112 may serve as an anode of the laser array, and the subsequently formed second electrode 128 may serve as a cathode of the laser array.

[0134] In other examples, the first electrode 112 may serve as a cathode of the laser array, and the subsequently formed second electrode 128 may serve as an anode of the laser array.

[0135] It should be noted that, in some examples of the present disclosure, the first pad 110 and the first contact layer 104 may be made of the same material.

[0136] In other examples, the materials of the first pad 110 and the first contact layer 104 may be different. The examples disclosed herein do not limit the materials of the first pad 110 and the first contact layer 104, as long as they can function as an electrical connection.

[0137] In some examples, to achieve isolation between adjacent first electrodes, the laser array may further include a second passivation layer for electrical isolation.

[0138] As an example, with continued reference to FIG. 2 , the laser array may further include a third trench, and the third trench may penetrate at least one layer of the epitaxial layer 102 .

[0139] In some examples, as shown in FIG. 2 , the third trench may sequentially penetrate the pDBR layer, the QW layer, and at least a portion of the nDBR layer.

[0140] In some other examples, the third trench may penetrate the pDBR layer and at least a portion of the QW layer in the epitaxial layer 102 .

[0141] In this case, with continued reference to FIG2 , the first pad 110 may further extend into the third trench. In some examples, with continued reference to FIG2 , the laser array may further include a second passivation layer 108. The second passivation layer 108 is at least partially located on the inner wall of the third trench and extends along the inner wall of the third trench to the first surface of the epitaxial layer 102 and the top of the first contact layer 104.

[0142] In some examples, the first pad 110 located in the third trench directly contacts the epitaxial layer 102. Both the first pad 110 and the epitaxial layer 102 are conductive. By forming a second passivation layer 108 on the inner wall of the third trench, electrical isolation can be achieved between the first pad 110 located in the third trench and the epitaxial layer 102, reducing or preventing the current generated by the laser from being transmitted in a direction parallel to the first surface, thereby improving the light-emitting performance of the laser array.

[0143] In some examples, when forming the third trench, with continued reference to FIG. 2 , an oxide layer 106 may be formed by laterally oxidizing at least a portion of the quantum well layer on the inner wall of the third trench.

[0144] By forming the oxide layer 106 , current can be guided through the oxide apertures, through the active region of the quantum well layer, and toward the n-doped epitaxial layer of the epitaxial layer 102 .

[0145] In some embodiments, in order to reduce the area occupied by the non-luminous region of the first surface of the epitaxial layer, the second electrode can be located on the second surface of the epitaxial layer, thereby increasing the area occupied by the light-emitting surface of the first surface and improving the duty ratio of the light-emitting surface.

[0146] 2 , the second electrode 128 may include a second contact layer 118 and a second pad 126. The second contact layer 118 may be located on the second surface of the epitaxial layer 102. The second pad 126 may be electrically connected to the second contact layer 118, and the second pad 126 may be at least partially located on the second surface of the epitaxial layer 102.

[0147] In some embodiments of the present disclosure, the second contact layer 118 may serve as a portion of the semiconductor device connected to an external circuit. The second contact layer 118 has good conductive properties and can form a good ohmic contact with the semiconductor material.

[0148] In some examples, the second contact layer 118 may be composed of metal or a highly doped semiconductor material.

[0149] In some examples, the second contact layer 118 may be an n-type contact layer or a p-type contact layer.

[0150] In some examples, the second pad 126 may be composed of metal or a highly doped semiconductor material.

[0151] In some examples of the present disclosure, the second pad 126 and the second contact layer 118 as a whole can serve as a second electrode 128 of the laser array. Through the second electrode 128, the laser array can be connected to an external circuit.

[0152] And since the second electrode is arranged on the second surface of the epitaxial layer, the second electrode with a larger size can be designed, which can reduce the resistance of the second electrode and the impact of the resistance, which is beneficial to the current injection into each light-emitting cavity and can improve the detection performance of the lidar.

[0153] It should be noted that, in some examples of the present disclosure, the second pad 126 and the second contact layer 118 may be made of the same material.

[0154] In some other examples, the materials of the second pad 126 and the second contact layer 118 may be different. The present disclosure does not limit the materials of the second pad 126 and the second contact layer 118, as long as they can function as an electrical connection.

[0155] 2 , the laser array may further include a transparent substrate 116 . The transparent substrate 116 is located on the first surface side of the epitaxial layer 102 and covers the first electrode 112 and the first surface of the epitaxial layer 102 .

[0156] In some examples, the transparent substrate 116 may be a sapphire substrate, and the laser light emitted through the first surface side of the epitaxial layer 102 may be projected to the outside through the transparent substrate 116 .

[0157] By arranging a transparent substrate on the first surface side and making the transparent substrate cover the first electrode and the first surface of the epitaxial layer, the mechanical strength of the laser array can be enhanced while reducing the impact on the laser light emission.

[0158] In some examples, to enhance adhesion between the transparent substrate 116 and the first surface of the epitaxial layer 102 , the laser array may further include an adhesion layer 114 . The adhesion layer 114 may be located between the first surface of the epitaxial layer 102 and the transparent substrate 116 .

[0159] The bottom of the adhesion layer 114 is bonded to the first surface side of the epitaxial layer 102 and at least partially covers the first electrode 112 and the first surface of the epitaxial layer 102. The top of the adhesion layer 114 is bonded to the bottom of the transparent substrate 116.

[0160] 2 , in some embodiments, the first isolation structure 122 may include a first trench G12 and a first passivation layer 120. The first trench G12 may be located between at least a portion of adjacent second electrodes 128, and the first trench G12 may penetrate at least one layer of the epitaxial layer 102. The first passivation layer 120 may be at least partially located on an inner wall of the first trench G12 and extend along the inner wall of the first trench G12 to the second surface of the epitaxial layer 102.

[0161] In some examples, the material of the first passivation layer 120 may include a dielectric material. For example, the dielectric material may be a silicon-containing dielectric material, such as silicon nitride, silicon oxynitride, silicon oxycarbonitride, silicon boron carbonitride, or the like.

[0162] In some examples, to enable a subsequently formed second pad to be electrically connected to the second contact layer, as shown in FIG. 2 , the first passivation layer 120 may further expose at least a portion of the top of the second contact layer 118 .

[0163] By forming a first passivation layer in the first trench, in a partial area of ​​the second surface of the epitaxial layer, and on top of the second contact layer, electrical isolation between adjacent second electrodes can be achieved, preventing current from flowing between adjacent light-emitting cavities, thereby enabling individual control of some of the second electrodes and, in turn, independently controlling the formed semiconductor laser.

[0164] In some embodiments, projections of the first trench G12 and the third trench in a direction perpendicular to the first surface of the epitaxial layer 102 may at least partially overlap.

[0165] In FIG2 , the projections of the first trench G12 and the third trench in a direction perpendicular to the first surface of the epitaxial layer 102 overlap, and by overlapping the projections of the two, the depth of etching the first trench from the second surface to the first surface can be reduced, thereby reducing the difficulty of the process.

[0166] In some examples, to reduce packaging difficulty and cost, with continued reference to FIG. 2 , the laser array may further include: a through hole T11 passing through the epitaxial layer 102 .

[0167] In some examples, when forming the through hole T11 , the top of the inner wall of the through hole may also expose the bottom of the first electrode 112 .

[0168] 2 , the first electrode 112 may further extend to the second surface of the epitaxial layer 102 through the through hole T11 .

[0169] Through the through hole T11, a first electrode 112 can be formed on the first surface and the second surface of the epitaxial layer 102, so that the bottom of the first electrode 112 is electrically connected to the top of the first electrode 112 in the through hole T11, and the first electrode 112 and the second electrode 128 both include a portion located on the second surface of the epitaxial layer 102. The laser array can be directly attached to an external circuit (for example, a laser driver chip or a laser driver circuit) to achieve electrical connection between the laser array and the external circuit, thereby reducing packaging difficulty and cost.

[0170] When the first electrode 112 is extended to the second surface of the epitaxial layer 102 through the through hole T11 , it is considered that the first electrode 112 and the second electrode 128 may be directly connected, resulting in a short circuit problem in the laser array.

[0171] In some examples, the laser array may further include a second trench G13 , which may be located between the through hole T11 and at least some of the second electrodes 128 , and may penetrate at least one layer of the epitaxial layer 102 .

[0172] In some examples, the projections of the second trench and the third trench in a direction perpendicular to the first surface of the epitaxial layer overlap, and by overlapping the projections of the two, the depth of etching the second trench from the second surface to the first surface can be reduced, thereby reducing the process difficulty.

[0173] At least a portion of the first passivation layer 120 may be located on an inner wall of the second trench G13 and extend along the inner wall of the second trench G13 to the second surface of the epitaxial layer 102 , wherein the first passivation layer 120 and the second trench G13 serve as a second isolation structure 124 .

[0174] When the first electrode 112 and the second electrode 128 are both located on the second surface of the epitaxial layer 102, by setting the second isolation structure 124, lateral (for example, the horizontal direction in FIG. 2 ) electrical insulation can be provided between the first electrode 112 and the second electrode 128, thereby reducing or avoiding the occurrence of short circuit problems, thereby promoting the flow of current through the epitaxial layer 102 and improving the luminous efficiency of the laser array.

[0175] In some examples, the first passivation layer 120 can at least partially extend to the inner wall of the through hole T11 to achieve electrical isolation between the first electrode 112 and the epitaxial layer 102 in the through hole T11, reduce or prevent current from being transmitted in a direction parallel to the first surface, and further improve the luminous efficiency of the laser array.

[0176] As described above, FIG2 is merely an example of the structure of the laser array in the present disclosure. Furthermore, although FIG2 is described with respect to a VCSEL, the exemplary embodiment described in conjunction with FIG2 may also include vertically emitting laser diodes and / or other types of vertically emitting devices.

[0177] As another example, etching may be performed from the second surface of the epitaxial layer to form an isolation structure to achieve independent light emission of each light emitting cavity.

[0178] For example, see FIG3 , which is a schematic structural diagram of another example of a laser array in an embodiment of the present disclosure.

[0179] 3 , compared to the embodiment shown in FIG. 2 , the projections of the first trench G12 and the third trench shown in FIG. 3 in the direction perpendicular to the first surface of the epitaxial layer 102 do not overlap with each other.

[0180] In some embodiments, as shown in FIG. 3 , the first trench G12 may be located between two adjacent third trenches.

[0181] In some examples, in a direction perpendicular to the first surface of the epitaxial layer, the projections of the first trench G42 and the oxide layer 406 do not overlap with each other, thereby reducing or avoiding the impact on the oxide layer 406 when etching the epitaxial layer 302 to form the first trench G42, thereby improving the quality of the formed oxide layer 406.

[0182] As described above, FIG3 is merely an example of the structure of the laser array in the present disclosure. Furthermore, although FIG3 is described with respect to a VCSEL, the laser array may also include vertically emitting laser diodes and / or other types of vertically emitting devices in conjunction with the exemplary embodiment described in FIG3 .

[0183] In order to enable those skilled in the art to better understand and implement the formation process of the laser array in the present disclosure, the embodiments of the present disclosure are described below with reference to the accompanying drawings.

[0184] Refer to FIG. 4 to FIG. 15 for structural schematic diagrams corresponding to each step in a method for forming an example of a laser array in an embodiment of the present disclosure.

[0185] 4 , a substrate 300 is provided, which can provide a process platform for subsequently forming other epitaxial structures.

[0186] In some examples, substrate 300 may be formed of various semiconductor materials, such as tri- to penta-semiconductors (e.g., gallium arsenide (GaAs), indium gallium arsenide (InGaAs), indium phosphide (InP), etc.); or quad-semiconductors (e.g., silicon (Si), silicide, etc.).

[0187] In some examples, substrate 300 may be doped with various materials to form an n-type substrate or a p-type substrate.

[0188] For example, a p-doped GaAs substrate or an n-doped GaAs substrate, a p-doped InGaAs substrate or an n-doped InGaAs substrate, a p-doped InP substrate or an n-doped InP substrate, etc. can be formed through doping treatment.

[0189] 5 , an epitaxial layer 302 is formed on the substrate 300 by epitaxial growth.

[0190] In some examples, the epitaxial layer 302 may include one or more n-doped epitaxial layers, wherein the n-doped epitaxial layer may include an n-doped distributed Bragg reflector layer and / or an n+ doped buffer layer.

[0191] In some examples, the nDBR layer can include alternating layers of n-doped gallium arsenide (GaAs) and n-doped aluminum gallium arsenide (AlGaAs).

[0192] In some examples, the n+ doped buffer layer may include only gallium arsenide (GaAs) and may be thicker than each of the alternating nDBR layers, thereby reducing the difficulty of etching the n+ doped buffer layer.

[0193] It should be noted that, in the embodiment of the present disclosure, FIG5 and subsequent figures illustrate an example in which the epitaxial layer 302 includes an nDBR layer. In other embodiments of the present disclosure, the epitaxial layer 102 may further include an n+ doped buffer layer.

[0194] In some examples, the epitaxial layer 302 may include one or more p-doped epitaxial layers formed on an n-doped epitaxial layer, wherein the p-doped epitaxial layer may be a p-doped distributed Bragg reflector (pDBR) layer.

[0195] In some embodiments, the p-doped epitaxial layer and the n-doped epitaxial layer may form a semiconductor mirror.

[0196] In some examples, epitaxial layer 302 can include one or more active layers including one or more quantum well layers.

[0197] In some examples of the present disclosure, an epitaxial process may be used to sequentially form an nDBR layer, one or more QW layers, and a pDBR layer on the substrate 300 to form the epitaxial layer 302 .

[0198] In some examples, the epitaxial layer 302 may have a first surface SF1 and a second surface SF2 , wherein the second surface SF2 may be located between the substrate 300 and the first surface SF1 .

[0199] For example, in some examples, the second surface is a surface close to the substrate 300 .

[0200] In some other examples, the first surface SF1 may be located between the substrate 300 and the second surface SF2 .

[0201] In some embodiments, the first surface SF1 of the epitaxial layer 302 may be used as a light emitting surface, that is, laser light may be emitted from the first surface SF1 side.

[0202] In some other embodiments, the second surface SF2 of the epitaxial layer 302 may be used as a light emitting surface, that is, the laser light may be emitted from the second surface SF2 side.

[0203] 6 to 9 , a first electrode 312 is formed at least partially on the first surface SF1 of the epitaxial layer 302 (see FIG. 9 ).

[0204] In some embodiments, the first electrode 312 may be formed as follows:

[0205] As shown in FIG. 6 , a first contact layer 304 is formed on a portion of the first surface of the epitaxial layer 302 .

[0206] In some examples, the first contact layer 304 may be formed using a physical vapor deposition process, such as an electron beam (E-beam) evaporation deposition process.

[0207] In some other examples, the process of forming the first contact layer 304 may include: depositing a first contact material layer on top of the first surface of the epitaxial layer 302 (for example, it may be a pDBR layer), and then etching the first contact material layer to form the first contact layer 304, and the first contact layer 304 may expose a portion of the top of the first surface of the epitaxial layer 302.

[0208] In some embodiments of the present disclosure, the first contact layer 304 may serve as a portion of the semiconductor device connected to an external circuit. The first contact layer 304 has good electrical conductivity and can form a good ohmic contact with the semiconductor material.

[0209] In some examples, the first contact layer 304 may be made of metal (eg, metals with good electrical conductivity, such as gold, silver, copper, and aluminum) or highly doped semiconductor materials.

[0210] In some examples, the first contact layer 304 may be a p-type contact layer.

[0211] In some other examples, the first contact layer 304 may be an n-type contact layer.

[0212] It should be noted that the number and distribution positions of the first contact layers shown in FIG6 are merely examples, and are used to illustrate that a film layer for connecting to an external circuit can be formed on top of the epitaxial layer.

[0213] In some embodiments, in order to achieve isolation between multiple first electrodes subsequently formed by the first pad and the first contact layer, as well as electrical isolation between the first electrode located in the epitaxial layer and the epitaxial layer, a second passivation layer for electrical isolation can also be formed after forming a first contact layer at least partially located on the first surface of the epitaxial layer.

[0214] As an example, as shown in FIG. 7 , a third trench G31 is formed penetrating at least one layer of the epitaxial layer 302 .

[0215] In some examples, as shown in FIG. 7 , the third trench G31 may be formed by sequentially penetrating the pDBR layer, the QW layer, and at least a portion of the nDBR layer in the epitaxial layer 302 .

[0216] In some other examples, the third trench G31 may be formed through the pDBR layer and at least a portion of the QW layer in the epitaxial layer 302 .

[0217] In some embodiments, the third trench G31 may be formed by using a plasma etching process (eg, inductively coupled plasma reactive ion etching).

[0218] For example, an anti-reflective coating and a photoresist layer are sequentially formed on the epitaxial layer, wherein the photoresist layer has a graphic opening exposing a portion of the anti-reflective coating. The photoresist layer is used as a mask and a plasma etching process is adopted to sequentially etch the first anti-reflective coating and the epitaxial layer along the graphic opening, and the epitaxial layer exposed by the graphic opening is removed, thereby forming a third groove G31.

[0219] 7 , after the third trench G31 is formed, at least one epitaxial layer 302 on both sides of the third trench G31 may be oxidized to form an oxide layer 306 .

[0220] In some examples, as shown in FIG. 7 , the quantum well layer on both sides of the third trench G31 may be oxidized to form the oxide layer 306 on the quantum well layer.

[0221] As an example, the oxide layer 306 may be formed by a wet oxidation process.

[0222] By forming the oxide layer 306 , current can be guided through the oxide aperture and then through the active region of the quantum well layer, and the current can flow toward the n-doped epitaxial layer of the epitaxial layer 302 .

[0223] 8 , a second passivation layer 308 is formed on a portion of the first surface of the epitaxial layer 302 and on top of the first contact layer 304 . The second passivation layer 308 may extend to an inner wall of the third trench G31 .

[0224] In some examples, a plasma-enhanced chemical vapor deposition (PECVD) process can be used to form the second passivation layer. Using the PECVD process allows the second passivation layer to be evenly coated on the surface to be deposited, covering the third trench, thereby improving device performance and reliability. Furthermore, the formed second passivation layer can be firmly attached to the substrate and is not easily peeled off or detached, thereby improving device stability and reliability.

[0225] In some examples, the second passivation layer may be formed by an atomic layer deposition (ALD) process. The embodiments of the present disclosure do not impose any limitation on the method of forming the second passivation layer.

[0226] In some examples, the material forming the second passivation layer may include a dielectric material, such as a silicon-containing dielectric material, such as silicon nitride, silicon oxynitride, silicon oxycarbonitride, silicon boron carbonitride, etc.

[0227] In some examples, to enable a subsequently formed first pad to be electrically connected to the first contact layer, as shown in FIG. 8 , when forming the second passivation layer 308 , the second passivation layer 308 may also expose at least a portion of the top of the first contact layer 304 .

[0228] By forming the second passivation layer in the third trench, a portion of the first surface of the epitaxial layer and the top of the first contact layer, electrical isolation between adjacent first contact layers can be achieved, thereby improving the luminescence performance of the laser array.

[0229] 9 , a first pad 310 electrically connected to the first contact layer 304 is formed on the first surface of the epitaxial layer 302 . The first pad 310 may extend into the third trench G31 .

[0230] In some examples, the first pad 310 may be formed using an electron beam deposition process, for example:

[0231] A high-energy electron beam is generated by an electron gun, and the electron beam is guided and accelerated to the surface of the first pad material layer through electric and magnetic fields. When the electron beam hits the surface of the first pad material layer, its energy can be converted into thermal energy to heat the first pad material layer to an evaporation temperature. The first pad material layer can contact the surface of the substrate and condense to form a first pad.

[0232] By controlling the energy and focus, the deposition process can be controlled to form a first pad 310 as shown in FIG. 9 , which is electrically connected to the first contact layer 304 and extends into the third trench G31 .

[0233] In some examples, the first pad 310 may be composed of metal or a highly doped semiconductor material.

[0234] In some examples of the present disclosure, the first pad 310 and the first contact layer 306 may serve as a first electrode 312 of the laser array. Through the first electrode 312 , the laser array can be connected to an external circuit.

[0235] In some examples, the first electrode 312 can serve as an anode of the laser array, and the subsequently formed second electrode 328 (as shown in FIG. 15 ) can serve as a cathode of the laser array.

[0236] In some other examples, the first electrode 312 can serve as the cathode of the laser array, and the subsequently formed second electrode 328 can serve as the anode of the laser array. In this case, the first contact layer 304 is an n-type contact layer, and the second contact layer 318 can be a p-type contact layer.

[0237] It should be noted that, in some examples of the present disclosure, the materials forming the first pad 310 and the first contact layer 306 may be the same.

[0238] In some other examples, the materials forming the first pad 310 and the first contact layer 306 may be different. The present disclosure does not limit the materials forming the first pad 310 and the first contact layer 306, as long as the two can function as an electrical connection.

[0239] In some embodiments, in order to reduce the area occupied by the non-luminous region of the first surface of the epitaxial layer, the second electrode can be located on the second surface of the epitaxial layer, thereby increasing the area occupied by the light-emitting surface of the first surface and improving the duty ratio of the light-emitting surface.

[0240] In some examples, after removing the substrate, a second electrode may be formed on the second surface of the epitaxial layer.

[0241] As an example, referring to FIG. 10 , the substrate 300 may be at least partially removed to form a second electrode 328 on the second surface of the epitaxial layer 302 (as shown in FIG. 15 ).

[0242] In some examples, the substrate 300 may be at least partially removed by at least one of a mechanical grinding process, a chemical mechanical planarization process, a wet etching process, and a back grinding process.

[0243] In some embodiments, the entire substrate may be removed. In other embodiments, a portion of the substrate may be removed. In some examples of the present disclosure, the entire substrate is removed as an example for illustration.

[0244] By removing the substrate, the thickness of the laser array can be reduced, making it easier to form other structures on the second surface of the epitaxial layer, such as a second electrode, a first passivation layer, etc.

[0245] In some examples, after removing the substrate and before forming a plurality of second electrodes at least partially located on the second surface of the epitaxial layer, the method for forming a laser array may further include:

[0246] 11 , a transparent substrate 316 and an adhesive layer 314 are provided.

[0247] The bottom of the adhesion layer 314 is bonded to the first surface side of the epitaxial layer 302 , and the adhesion layer 314 at least partially covers the first electrode 312 and the first surface of the epitaxial layer 302 .

[0248] The transparent substrate 316 is bonded to the top of the adhesion layer 314 .

[0249] In some examples, the transparent substrate 316 may be a sapphire substrate, and the laser light emitted through the first surface side of the epitaxial layer 302 may be projected to the outside through the transparent substrate 316 .

[0250] In some examples, the adhesive layer 314 may be a substance having adhesive properties, for example, the adhesive layer 314 may be adhesive glue.

[0251] In some examples, light in the operating wavelength band of the semiconductor laser can pass through the pair of transparent substrate 316 and adhesion layer 314 .

[0252] In some other embodiments, other methods may be used to form the structure shown in Figure 11. For example, the transparent substrate may be bonded to the top of the adhesion layer first, and then the bottom of the adhesion layer may be bonded to the first surface side of the epitaxial layer.

[0253] The above-described exemplary solution, on the one hand, by providing a transparent substrate on the first surface side of the epitaxial layer and covering the first electrode and the first surface of the epitaxial layer, can enhance the mechanical strength of the laser array without affecting laser light output, facilitating subsequent processing on the second surface of the epitaxial layer. On the other hand, by providing an adhesive layer between the first surface of the epitaxial layer and the transparent substrate, the adhesion between the transparent substrate and the first surface side of the epitaxial layer can be enhanced.

[0254] After forming an adhesion layer and a transparent substrate in sequence on the first surface side of the epitaxial layer, the adhesion layer and the transparent substrate can be used as a processing platform for the epitaxial structure, and then a plurality of second electrodes can be formed on the second surface of the epitaxial layer.

[0255] As an example, referring to FIG. 12 , a second contact layer 318 is formed on a portion of the second surface of the epitaxial layer 302 .

[0256] In some examples, the second contact layer 318 may be formed using a physical vapor deposition process, such as an electron beam (E-beam) evaporation deposition process.

[0257] In some other examples, the process of forming the second contact layer 318 may also include: depositing a second contact material layer on the top of the second surface of the epitaxial layer 302 (for example, it can be an nDBR layer), and then etching the second contact material layer to form a second contact layer 318, and the second contact layer 318 can expose a portion of the top of the second surface of the epitaxial layer 302.

[0258] In some embodiments of the present disclosure, the second contact layer 318 may serve as a portion of the semiconductor device connected to an external circuit. The second contact layer 318 has good conductive properties and can form a good ohmic contact with the semiconductor material.

[0259] In some examples, the second contact layer 318 can be composed of metal or a highly doped semiconductor material.

[0260] In some examples, the second contact layer 318 can be an n-type contact layer.

[0261] In some other examples, the second contact layer 318 may be a p-type contact layer.

[0262] In some embodiments, to achieve electrical isolation between at least some adjacent second electrodes, a first isolation structure for electrical isolation may be provided between at least some adjacent second electrodes.

[0263] As an example, as shown in FIG. 13 and FIG. 14 , a method of forming the first isolation structure 322 may include:

[0264] 13 , a first trench G32 is formed between at least portions of adjacent second contact layers 318 . The first trench G32 may penetrate at least one layer of the epitaxial layer 302 .

[0265] In some examples, as shown in FIG. 13 , a first trench G32 may be formed by penetrating the nDBR layer in the epitaxial layer 302 .

[0266] In some examples, the first trench G32 at least partially overlaps with the projection of the third trench G31 (see FIG. 8 ) in a direction perpendicular to the first surface of the epitaxial layer 302 .

[0267] In FIG. 13 , the projections of the first trench G32 and the third trench G31 in the direction perpendicular to the first surface of the epitaxial layer 302 overlap.

[0268] By making the projections of the first trench G32 and the third trench G31 in a direction perpendicular to the first surface of the epitaxial layer 302 overlap, the depth of the third trench etched from the first surface to the second surface can be reduced, thereby reducing the process difficulty.

[0269] In some other examples, projections of the first trench G32 and the third trench G31 in a direction perpendicular to the first surface of the epitaxial layer 302 may partially overlap.

[0270] In some embodiments, the first trench G32 may be formed by using a plasma etching process (eg, inductively coupled plasma reactive ion etching).

[0271] For example, an anti-reflective coating and a photoresist layer are sequentially formed on the second surface of the epitaxial layer, wherein the photoresist layer has a graphic opening exposing a portion of the anti-reflective coating. The photoresist layer is used as a mask and a plasma etching process is adopted to sequentially etch the first anti-reflective coating and the epitaxial layer along the graphic opening, and the epitaxial layer exposed by the graphic opening is removed, thereby forming a first groove G32.

[0272] In some examples, with continued reference to FIG. 13 , after forming the first trench G32 , a portion of the second passivation layer 308 may be removed to expose the bottom of the first electrode 312 .

[0273] In some examples, the projections of the first trench and the third trench in a direction perpendicular to the first surface of the epitaxial layer overlap. By overlapping the projections of the first trench and the third trench, the depth of etching the first trench from the second surface to the first surface can be reduced, thereby reducing process difficulty. Referring to FIG. 14 , a first passivation layer 320 is formed on the inner wall of the first trench G32. The first passivation layer 320 can extend along the inner wall of the first trench G32 to the second surface of the epitaxial layer 302.

[0274] In some examples, the first passivation layer may be formed by a plasma enhanced chemical vapor deposition process or an atomic layer deposition process, wherein the formation process may refer to the description of the second passivation layer.

[0275] In some examples, the material forming the first passivation layer may include a dielectric material, such as a silicon-containing dielectric material, such as silicon nitride, silicon oxynitride, silicon oxycarbonitride, silicon boron carbonitride, or the like.

[0276] In some examples, to enable a subsequently formed second pad to be electrically connected to the second contact layer, as shown in FIG. 14 , when forming the first passivation layer 320 , the first passivation layer 320 may also expose at least a portion of the top of the second contact layer 318 .

[0277] By forming a first passivation layer in the first trench, in a partial area of ​​the second surface of the epitaxial layer, and on top of the second contact layer, electrical isolation between adjacent second contact layers can be achieved, current flow between adjacent light-emitting cavities can be reduced or prevented, and individual control of part of the second electrode can be achieved, thereby independently controlling the formed semiconductor laser.

[0278] In some examples, to reduce packaging difficulty and cost, with continued reference to FIG. 13 , the method for forming the laser array may further include forming a through hole T31 passing through the epitaxial layer 302 .

[0279] In some examples, the way of forming the through hole T31 can refer to the description of the first trench G32 and the third trench G31 in the above examples.

[0280] In some examples, when forming the through hole T31 , a portion of the second passivation layer 308 may be removed to expose the bottom of the first electrode 312 .

[0281] 15 , forming the first electrode 312 on the first surface of the epitaxial layer 302 may further include extending the first electrode 312 to the second surface of the epitaxial layer 302 along the through hole T31 .

[0282] Through the through hole T31, a first electrode 312 can be formed on the first and second surfaces of the epitaxial layer 302, such that the bottom of the first electrode 312 is electrically connected to the top of the first electrode 312 in the through hole T31. The first electrode 312 and the second electrode 328 both include portions located on the second surface of the epitaxial layer 302. This allows the laser array to be directly attached to an external circuit (e.g., a laser driver chip or laser driver circuit), achieving electrical connection between the laser array and the external circuit, reducing packaging difficulty and cost.

[0283] In some examples, with continued reference to FIG. 15 , forming the second electrode 328 on the second surface of the epitaxial layer 302 may further include:

[0284] A second pad 326 electrically connected to the second contact layer 318 is formed.

[0285] In some examples, the second pad 326 may be formed by an electron beam deposition process. The formation process may refer to the description of the first pad.

[0286] In some examples, the second pad 326 may be composed of metal or a highly doped semiconductor material.

[0287] In some examples of the present disclosure, the second pad 326 and the second contact layer 318 may serve as a second electrode 328 of the laser array. The laser array can be connected to an external circuit through the second electrode 328 .

[0288] By setting the second electrode on the second surface of the epitaxial layer, the size of the second electrode can be enlarged, which can reduce the resistance of the second electrode and the impact of the resistance, which is beneficial to the current injection into each light-emitting cavity and can improve the detection performance of the lidar.

[0289] It should be noted that, in some examples of the present disclosure, the second pad 326 and the second contact layer 318 may be formed of the same material.

[0290] In other examples, the materials forming the second pad 326 and the second contact layer 318 may be different. The present disclosure does not limit the materials forming the second pad 326 and the second contact layer 318, as long as the two can function as an electrical connection.

[0291] When the first electrode 312 is extended to the second surface of the epitaxial layer 302 through the through hole T31 , it is considered that the first electrode 312 and the second electrode 328 may be directly connected, resulting in a short circuit problem in the laser array.

[0292] Based on this, when the first electrode 312 and the second electrode 328 are both located on the second surface of the epitaxial layer 302 , a second isolation structure 324 for achieving electrical isolation between the first electrode 312 and the second electrode 328 may also be formed.

[0293] As an example, referring to FIG. 14 , before extending the first electrode 312 along the through hole T31 to the second surface of the epitaxial layer 302 and forming the second pad 326 electrically connected to the second contact layer 318 , the following steps may also be included:

[0294] A second trench G33 is formed between the through hole T31 and some of the second electrodes 328 . The second trench G33 may penetrate at least one layer of the epitaxial layer 302 .

[0295] The first passivation layer 320 is formed in the second trench G33 , and the first passivation layer 320 extends along the inner wall of the second trench G33 to the second surface of the epitaxial layer 302 .

[0296] The method of forming the second groove G33 may refer to the above example.

[0297] When the second trench G33 is formed, the first passivation layer 320 may also be formed in the second trench G33 . The first passivation layer 320 and the second trench G33 may together serve as a second isolation structure 324 .

[0298] In this way, when the first electrode 312 and the second electrode 328 are both located on the second surface of the epitaxial layer 302, by setting the second isolation structure 324, lateral (for example, the horizontal direction in FIG. 14 ) electrical insulation can be provided between the first electrode 312 and the second electrode 328, thereby reducing or avoiding the occurrence of short circuit problems, thereby promoting the flow of current through the epitaxial layer 302 and improving the luminous efficiency of the laser array.

[0299] In some examples, with continued reference to FIG. 14 , before extending the first electrode 312 along the through hole T31 to the second surface of the epitaxial layer 302 and forming the second pad 326 electrically connected to the second contact layer 318 , the following steps may also be included:

[0300] The first passivation layer 320 is formed on the inner wall of the through hole T31 . The first passivation layer 320 can be used to achieve electrical isolation between the first electrode 312 and the epitaxial layer 302 located in the through hole T31 .

[0301] In the aforementioned disclosed example, the method of forming a first trench, then forming a through hole, and finally forming a second trench, and extending the first passivation layer to the through hole and the second trench is used for illustration.

[0302] In some other examples, the first trench, the through-hole, and the second trench can be formed in the same step, and a first passivation layer can be formed in another step. The first passivation layer is located on the inner wall of the first trench, the second trench, and the inner wall of the through-hole, and extends to the second surface of the epitaxial layer. In yet another step, a second contact layer is formed, and the first electrode is extended along the through-hole to the second surface.

[0303] In some other examples, the first trench and the second trench can be formed in the same step, the through-hole can be formed in another step, and the first passivation layer can be formed in yet another step. The formed first passivation layer can be located on the inner wall of the first trench, the second trench, and the inner wall of the through-hole, and extend to the second surface of the epitaxial layer. In yet another step, the second contact layer can be formed, and the first electrode can be extended along the through-hole to the second surface.

[0304] Refer to the structural schematic diagrams corresponding to the steps in the method for forming another example of a laser array in an embodiment of the present disclosure shown in Figures 16 to 24.

[0305] The method of forming the substrate and the epitaxial layer on the substrate in this embodiment can refer to the description of the above examples.

[0306] 16 to 19 , a first electrode 412 is formed at least partially on the first surface of the epitaxial layer 402 (see FIG. 19 ).

[0307] In some embodiments, the first electrode 412 may be formed as follows, including:

[0308] As shown in FIG. 16 , a first contact layer 404 is formed on a portion of the first surface of the epitaxial layer 402 .

[0309] In some examples, the first contact layer 404 may be formed by a physical vapor deposition process, for example, an electron beam evaporation deposition process.

[0310] In some other examples, the process of forming the first contact layer 404 may include: depositing a first contact material layer on top of the first surface of the epitaxial layer 402 (for example, it may be a pDBR layer), and then etching the first contact material layer to form the first contact layer 404, and the first contact layer 404 may expose a portion of the top of the first surface of the epitaxial layer 402.

[0311] In some embodiments, the first contact layer 404 may serve as a portion of the semiconductor device connected to an external circuit. The first contact layer 404 has good electrical conductivity and can form a good ohmic contact with the semiconductor material.

[0312] In some examples, the first contact layer 404 may be composed of metal or a highly doped semiconductor material.

[0313] In some examples, the first contact layer 404 may be a p-type contact layer.

[0314] In some other examples, the first contact layer 404 may also be an n-type contact layer.

[0315] It should be noted that the number and distribution positions of the first contact layers shown in FIG16 are merely examples, and are used to illustrate that a film layer for connection with an external circuit can be formed on top of the epitaxial layer.

[0316] In some embodiments, in order to achieve isolation between multiple first electrodes subsequently formed by the first pad and the first contact layer, as well as electrical isolation between the first electrode located in the epitaxial layer and the epitaxial layer, a second passivation layer for electrical isolation can also be formed after forming a first contact layer at least partially located on the first surface of the epitaxial layer.

[0317] As an example, as shown in FIG17 , a third trench G41 is formed penetrating at least one layer of the epitaxial layer 402 .

[0318] In some examples, as shown in FIG. 17 , the third trench G41 may be formed by sequentially penetrating the pDBR layer, the QW layer, and at least a portion of the nDBR layer in the epitaxial layer 402 .

[0319] In some other examples, the third trench G41 is formed through the pDBR layer and at least a portion of the QW layer in the epitaxial layer 402 . Alternatively, the third trench G41 may be formed through at least a portion of the pDBR layer in the epitaxial layer 402 .

[0320] In some embodiments, the third trench G41 may be formed by using a plasma etching process (eg, inductively coupled plasma reactive ion etching).

[0321] For example, an anti-reflective coating and a photoresist layer are sequentially formed on the epitaxial layer, wherein the photoresist layer has a graphic opening exposing a portion of the anti-reflective coating layer. The photoresist layer is used as a mask and a plasma etching process is adopted to sequentially etch the first anti-reflective coating and the epitaxial layer along the graphic opening, and the epitaxial layer exposed by the graphic opening is removed, thereby forming a third groove G41.

[0322] In some examples, as shown in FIG. 17 , a plurality of third trenches G41 may be formed between two adjacent first contact layers 404 .

[0323] Continuing to refer to FIG. 17 , after the third trench G41 is formed, the quantum well layer on both sides of the third trench G41 may be oxidized to form an oxide layer 406 .

[0324] As an example, the oxide layer 406 may be formed by a wet oxidation process.

[0325] By forming the oxide layer 406 , current can be guided through the oxide aperture, and then through the active region of the quantum well layer, and can flow toward the n-doped epitaxial layer of the epitaxial layer 402 .

[0326] 18 , a second passivation layer 408 is formed on a portion of the first surface of the epitaxial layer 402 and on top of the first contact layer 404 . The second passivation layer 408 may extend to the inner wall of the third trench G41 .

[0327] In some examples, a plasma-enhanced chemical vapor deposition (PECVD) process can be used to form the second passivation layer. By using the PECVD process, the second passivation layer can be uniformly covered on the surface to be deposited and can cover the third trench, thereby improving the performance and reliability of the device. The formed second passivation layer can also be firmly attached to the substrate, thereby improving the stability and reliability of the device.

[0328] In some examples, the second passivation layer may be formed by an atomic layer deposition process. The embodiments of the present disclosure do not impose any limitation on the method of forming the second passivation layer.

[0329] In some examples, the material forming the second passivation layer may include a dielectric material, such as a silicon-containing dielectric material, such as silicon nitride, silicon oxynitride, silicon oxycarbonitride, silicon boron carbonitride, or the like.

[0330] In some examples, to enable the subsequently formed first pad to be electrically connected to the first contact layer, as shown in FIG. 18 , when forming the second passivation layer 408 , the second passivation layer 408 may also expose at least a portion of the top of the first contact layer 404 .

[0331] By forming the second passivation layer in the third trench, a portion of the first surface of the epitaxial layer and the top of the first contact layer, electrical isolation between adjacent first contact layers can be achieved, thereby improving the luminescence performance of the laser array.

[0332] 19 , a first pad 410 electrically connected to the first contact layer 404 is formed on the first surface of the epitaxial layer 402 . The first pad 410 may extend into the third trench G41 .

[0333] In some examples, the first pad 410 may be formed using an electron beam deposition process, for example:

[0334] A high-energy electron beam is generated by an electron gun, and the electron beam is guided and accelerated to the surface of the first pad material layer through electric and magnetic fields. When the electron beam hits the surface of the first pad material layer, its energy can be converted into thermal energy to heat the first pad material layer to an evaporation temperature. The first pad material layer can contact the surface of the substrate and condense to form a first pad.

[0335] By controlling the energy and focus, the deposition process can be controlled to form a first pad 410 as shown in FIG. 19 , which is electrically connected to the first contact layer 404 and extends into the third trench G41 .

[0336] In some examples, the first pad 410 may be composed of metal or a highly doped semiconductor material.

[0337] In some examples of the present disclosure, the first pad 410 and the first contact layer 406 may serve as a first electrode 412 of the laser array. Through the first electrode 412 , the laser array can be connected to an external circuit.

[0338] In some examples, the first electrode 412 may serve as an anode of the laser array, and the subsequently formed second electrode 428 may serve as a cathode of the laser array.

[0339] In some examples, the first electrode 412 can serve as a cathode of the laser array, and the subsequently formed second electrode 428 can serve as an anode of the laser array. In this case, the first contact layer 404 is an n-type contact layer, and the second contact layer 418 can be a p-type contact layer.

[0340] It should be noted that, in some examples of the present disclosure, the materials forming the first pad 410 and the first contact layer 406 may be the same.

[0341] In some other examples, the materials forming the first pad 410 and the first contact layer 406 may be different. The present disclosure does not limit the materials forming the first pad 410 and the first contact layer 406, as long as the two can function as an electrical connection.

[0342] In some embodiments, in order to reduce the area occupied by the non-luminous region of the first surface of the epitaxial layer, the second electrode can be located on the second surface of the epitaxial layer, thereby increasing the area occupied by the light-emitting surface of the first surface and improving the duty ratio of the light-emitting surface.

[0343] In some examples, after removing the substrate, a second electrode may be formed on the second surface of the epitaxial layer.

[0344] As an example, referring to FIG. 20 , the substrate 400 may be removed to form a second electrode 426 (see FIG. 24 ) on the second surface of the epitaxial layer 402 .

[0345] In some examples, the substrate 400 may be removed by using at least one of a mechanical grinding process, a chemical mechanical planarization process, a wet etching process, and a back grinding process.

[0346] The entire substrate may be removed, or only a portion of the substrate may be removed. In some examples of the present disclosure, the entire substrate is removed as an example for illustration.

[0347] By removing the substrate, the thickness of the laser array can be reduced, making it easier to form other structures on the second surface of the epitaxial layer, such as a second electrode, a first passivation layer, etc.

[0348] In some examples, after removing the substrate and before forming a plurality of second electrodes at least partially located on the second surface of the epitaxial layer, the method for forming a laser array may further include:

[0349] Referring to Figure 21, a transparent substrate 416 and an adhesion layer 414 are provided, the bottom of the adhesion layer 414 is bonded to the first surface side of the epitaxial layer 402, the adhesion layer 414 at least partially covers the first electrode 412 and the first surface of the epitaxial layer 402, and the transparent substrate 416 is bonded to the top of the adhesion layer 414.

[0350] In some examples, the transparent substrate 416 may be a sapphire substrate, and the laser light emitted through the first surface side of the epitaxial layer 402 may be projected to the outside through the transparent substrate 416 .

[0351] In some examples, the adhesive layer 414 may be a substance having adhesive properties. For example, the adhesive layer 314 may be adhesive glue.

[0352] In some examples, transparent substrate 416 and adhesion layer 414 are transparent to light in the operating wavelength band of the semiconductor laser.

[0353] In some other embodiments, other methods may be used to form the structure shown in Figure 21. For example, the transparent substrate may be bonded to the top of the adhesion layer first, and then the bottom of the adhesion layer may be bonded to the first surface side of the epitaxial layer.

[0354] The above-described exemplary solution, on the one hand, by providing a transparent substrate on the first surface side of the epitaxial layer and covering the first electrode and the first surface of the epitaxial layer, can enhance the mechanical strength of the laser array without affecting laser light output, facilitating subsequent processing on the second surface of the epitaxial layer. On the other hand, by providing an adhesive layer between the first surface of the epitaxial layer and the transparent substrate, the adhesion between the transparent substrate and the first surface side of the epitaxial layer can be enhanced.

[0355] After forming an adhesion layer and a transparent substrate in sequence on the first surface side of the epitaxial layer, the adhesion layer and the transparent substrate can be used as processing platforms for subsequent epitaxial structures, and then a plurality of second electrodes can be formed on the second surface of the epitaxial layer.

[0356] As an example, referring to FIG. 22 , a second contact layer 418 is formed on a portion of the second surface of the epitaxial layer 402 .

[0357] In some examples, the second contact layer 418 may be formed using a physical vapor deposition process, such as an electron beam evaporation deposition process.

[0358] In some disclosed embodiments, the second contact layer 418 may serve as a portion of the semiconductor device connected to an external circuit. The second contact layer 418 has good electrical conductivity and can form a good ohmic contact with the semiconductor material.

[0359] In some examples, the second contact layer 418 can be composed of metal or a highly doped semiconductor material.

[0360] In some examples, the second contact layer 418 can be an n-type contact layer.

[0361] In some other examples, the second contact layer 418 may be a p-type contact layer.

[0362] In some embodiments, to achieve electrical isolation between at least some adjacent second electrodes, a first isolation structure for electrical isolation may be provided between at least some adjacent second electrodes.

[0363] As an example, as shown in FIG. 23 and FIG. 24 , a method of forming the first isolation structure 422 may include:

[0364] 23 , a first trench G42 is formed between at least a portion of adjacent second contact layers 418 , and the first trench G42 penetrates at least one layer of the epitaxial layer 302 .

[0365] In some examples, as shown in FIG. 23 , a first trench G42 may be formed by penetrating the nDBR layer in the epitaxial layer 402 .

[0366] In some examples, projections of the first trench G42 and the third trench G41 in a direction perpendicular to the first surface of the epitaxial layer 302 may not overlap with each other.

[0367] As an example, the first trench G42 may be formed between two adjacent third trenches G41 (see FIG. 18 ).

[0368] In some examples, when etching the epitaxial layer 302 to form the first trench G42, the etching path can avoid the oxide layer 406. That is, in a direction perpendicular to the first surface, the projections of the first trench G42 and the oxide layer 406 do not overlap with each other. This can reduce or avoid the impact on the oxide layer 406 and improve the quality of the formed oxide layer 406.

[0369] In some embodiments, the first trench G42 may be formed by using a plasma etching process (eg, inductively coupled plasma reactive ion etching).

[0370] For example, an anti-reflective coating and a photoresist layer are sequentially formed on the second surface of the epitaxial layer, wherein the photoresist layer has a graphic opening exposing a portion of the anti-reflective coating. The photoresist layer is used as a mask and a plasma etching process is adopted to sequentially etch the first anti-reflective coating and the epitaxial layer along the graphic opening, and the epitaxial layer exposed by the graphic opening is removed, thereby forming a first groove G42.

[0371] In some examples, with continued reference to FIG. 23 , after forming the first trench G42 , a portion of the second passivation layer 408 may be removed to expose the bottom of the first electrode 412 .

[0372] In some examples, the projections of the first trench and the third trench in a direction perpendicular to the first surface of the epitaxial layer overlap, and by overlapping the projections of the two, the depth of etching the first trench from the second surface to the first surface can be reduced, thereby reducing the difficulty of the process.

[0373] 24 , a first passivation layer 420 is formed on the inner wall of the first trench G42 . The first passivation layer 420 may extend along the inner wall of the first trench G42 to the second surface of the epitaxial layer 402 .

[0374] In some examples, the first passivation layer may be formed by a plasma enhanced chemical vapor deposition process or an atomic layer deposition process, wherein the formation process may refer to the description of the second passivation layer formation process.

[0375] In some examples, the material forming the first passivation layer may include a dielectric material, such as a silicon-containing dielectric material, such as silicon nitride, silicon oxynitride, silicon oxycarbonitride, silicon boron carbonitride, or the like.

[0376] In some examples, to enable a subsequently formed second pad to be electrically connected to the second contact layer, as shown in FIG. 23 , when forming the first passivation layer 420 , the first passivation layer 420 may also expose at least a portion of the top of the second contact layer 418 .

[0377] By forming a first passivation layer in the first trench, a partial area of ​​the second surface of the epitaxial layer and on top of the second contact layer, electrical isolation between adjacent second contact layers can be achieved, thereby enabling separate control of part of the second electrode and further independently controlling the formed semiconductor laser.

[0378] In some examples, to reduce packaging difficulty and cost, with continued reference to FIG. 23 , the method for forming a laser array may further include: forming a through hole T42 passing through the epitaxial layer 402 .

[0379] In some examples, the way of forming the through hole T42 can refer to the description of the first trench G42 in the above examples.

[0380] In some examples, when forming the through hole T42 , a portion of the second passivation layer 408 may be removed to expose the bottom of the first electrode 412 .

[0381] 24 , forming the first electrode 412 on the first surface of the epitaxial layer 402 may further include extending the first electrode 412 along the through hole T42 to the second surface of the epitaxial layer 402 .

[0382] By extending the first electrode 412 to the second surface of the epitaxial layer 402, so that the first electrode 412 and the second electrode 426 are both located on the second surface of the epitaxial layer 402, the laser array can be directly attached to an external circuit (for example, a laser driver chip or a laser driver circuit), thereby achieving electrical connection between the laser array and the external circuit and reducing packaging difficulty and cost.

[0383] In some examples, with continued reference to FIG. 24 , forming the second electrode 426 located on the second surface of the epitaxial layer 402 may further include:

[0384] A second pad 424 electrically connected to the second contact layer 418 is formed.

[0385] In some examples, the second pad 424 may be formed by an electron beam deposition process. For a specific formation process, refer to the description of the first pad.

[0386] In some examples, the second pad 424 may be composed of metal or a highly doped semiconductor material.

[0387] In some examples of the present disclosure, the second pad 424 and the second contact layer 418 as a whole can serve as the second electrode 426 of the laser array. Through the second electrode 426, the laser array can be connected to an external circuit.

[0388] Since the second electrode is arranged on the second surface of the epitaxial layer, the second electrode with a larger size can be designed, which can reduce the resistance of the second electrode and the impact of the resistance, which is beneficial to the current injection into each light-emitting cavity and can improve the detection performance of the lidar.

[0389] It should be noted that, in some examples of the present disclosure, the second pad 424 and the second contact layer 418 may be formed of the same material.

[0390] In other examples, the materials forming the second pad 424 and the second contact layer 418 may be different. The present disclosure does not limit the materials forming the second pad 424 and the second contact layer 418, as long as the two can function as an electrical connection.

[0391] When the first electrode 412 is extended to the second surface of the epitaxial layer 402 through the through hole T42 , it is considered that the first electrode 412 and the second electrode 426 may be directly connected, resulting in a short circuit problem in the laser array.

[0392] Based on this, when the first electrode 412 and the second electrode 426 are both located on the second surface of the epitaxial layer 402 , a second isolation structure for achieving electrical isolation between the second electrode 426 and the first electrode 412 may also be formed.

[0393] As an example, referring to FIG. 24 , before extending the first electrode 412 along the through hole T42 to the second surface of the epitaxial layer 402 and forming the second pad 424 electrically connected to the second contact layer 418 , the following steps may also be included:

[0394] A first passivation layer 420 is formed between the through hole T42 and some of the second electrodes 426 . The first passivation layer 420 may serve as a second isolation structure to achieve electrical isolation between the second electrode 426 and the first electrode 412 .

[0395] In this way, when the first electrode 412 and the second electrode 426 are both located on the second surface of the epitaxial layer 402, by setting a second isolation structure, lateral (for example, the horizontal direction in FIG. 24 ) electrical insulation can be provided between the first electrode 412 and the second electrode 426, thereby reducing or avoiding the occurrence of short circuit problems, thereby promoting the flow of current through the epitaxial layer 402 and improving the luminous efficiency of the laser array.

[0396] In some examples, the first electrode 412 located on the inner wall of the through hole T42 directly contacts the epitaxial layer 402 . Since both the first electrode 412 and the epitaxial layer 402 are conductive, the laser may be transmitted in a direction parallel to the first surface.

[0397] In some examples, with continued reference to FIG. 24 , before extending the first electrode 412 along the through hole T42 to the second surface of the epitaxial layer 402 and forming the second pad 424 electrically connected to the second contact layer 418 , the following steps may also be included:

[0398] The first passivation layer 420 is formed on the inner wall of the through hole T42 . The first passivation layer 420 can be used to electrically isolate the first electrode 412 located in the through hole T42 from the epitaxial layer 402 .

[0399] In the aforementioned disclosed example, the method of forming a first trench, then forming a through hole, and finally forming a second trench, and extending the first passivation layer to the through hole is used for illustration.

[0400] In some other examples, a first trench and a through-hole can be formed in the same step, and then a first passivation layer can be formed in the same step. The first passivation layer can be located on the inner wall of the first trench and the inner wall of the through-hole and extend to the second surface of the epitaxial layer. Finally, a second contact layer is formed, and at the same time, the first electrode is extended along the through-hole to the second surface.

[0401] The above disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementation to the precise form disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the implementation.

[0402] The number, arrangement, thickness, order, symmetry, and / or the like of the layers shown in the above figures and / or described herein are provided as examples. In practice, the launcher arrays and / or vertical launch devices shown in the figures and / or described herein may include configurations different from those shown in the figures and / or described herein.

[0403] Even though particular combinations of features are recited in the claims and / or disclosed in the disclosure, these combinations are not intended to limit the disclosure of the various implementations. In fact, many of these features can be combined in ways not specifically recited in the claims and / or disclosed in the disclosure. Although each dependent claim listed below may directly depend on only one claim, the disclosure of the various implementations includes each dependent claim in combination with every other claim in the claim set.

[0404] Unless explicitly stated otherwise, any element, act, or instruction used herein should not be construed as critical or essential. Furthermore, as used herein, the articles "a" and "an" are intended to include one or more items and can be used interchangeably with "one or more."

[0405] In a specific implementation, the laser array in the above example can be applied to various devices or equipment with detection functions.

[0406] As an example, as shown in FIG25 , the present disclosure further provides a laser radar, and the laser radar L0 may include:

[0407] Transmitter TX0, comprising a laser transmitter L01, configured to emit a light beam into an environment, wherein the laser transmitter L01 may comprise a laser array as described in any of the foregoing embodiments;

[0408] The receiver RX0 includes a detector L02 for receiving an echo of the light beam after it is reflected by one or more objects in the environment and generating a signal;

[0409] A processor (not shown in FIG25 ) is coupled to the detector L02 and is used to receive and process the signal to obtain at least one of the distance or reflectivity of the object.

[0410] Referring now to Figure 25 , as an example, the laser emitters L01 in transmitter TX0 can be arranged in a two-dimensional array. Laser emitters L01 can include vertical cavity surface emitting lasers (VCSELs). As shown in Figure 25 , the light emitted by laser emitters L01 is shaped by a transmitting lens group (not shown) and then emitted from the laser radar L0 in different directions to cover the laser radar's field of view (FOV).

[0411] As an example, the detector L02 in the receiver RX0 may include at least one of an avalanche photodiode (APD), a single photon avalanche diode (SPAD), and a silicon photomultiplier (SiPM), arranged in a two-dimensional array and corresponding to the arrangement of the laser emitter L01, so as to form multiple detection channels with the laser emitter L01 in the transmitter TX0.

[0412] In some embodiments, each detection channel may include a laser emitter and one or more detectors, or may be composed of one or more lasers and one detector, or may include multiple laser emitters and multiple detectors. Light signals emitted by lasers in the same detection channel, after being reflected by an object, can be received by the detectors in that same detection channel. The sub-fields of view of all detection channels together constitute the entire lidar's FOV.

[0413] The processor can be any chip, device or equipment with data processing capabilities, such as a single-chip microcomputer, a field programmable gate array (FPGA), a single-core or multi-core processor, and the specific hardware structure is not limited in the embodiments of the present disclosure.

[0414] Although the present disclosure is as described above, the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined by the claims.

Claims

1. A laser array, characterized in that, Comprising: A light-emitting cavity, the light-emitting cavity comprising an epitaxial layer; A first electrode, the first electrode being at least partially located on a first surface of the epitaxial layer; A plurality of second electrodes, the plurality of second electrodes being at least partially located on a second surface of the epitaxial layer; A first isolation structure, the first isolation structure being configured to provide electrical isolation between at least some adjacent second electrodes among the plurality of second electrodes.

2. The laser array according to claim 1, wherein The first isolation structure comprises: A first trench, the first trench being located between at least some adjacent second electrodes, and the first trench penetrating at least one layer of the epitaxial layer; A first passivation layer, at least partially located on an inner wall of the first trench and extending along the inner wall of the first trench to the second surface of the epitaxial layer.

3. The laser array according to claim 1 or 2, characterized in that, Further comprising: A through hole penetrating the epitaxial layer; The first electrode extends to the second surface of the epitaxial layer through the through hole.

4. The laser array according to claim 3, wherein The first passivation layer at least partially extends to the inner wall of the through hole; The laser array further comprises: A second isolation structure, including a part where the first passivation layer extends to the inner wall of the through hole.

5. The laser array according to claim 4, wherein Further comprising: A second trench, the second trench being located between the through hole and at least some second electrodes among the plurality of second electrodes, and the second trench penetrating at least one layer of the epitaxial layer; The first passivation layer is at least partially located on an inner wall of the second trench and extends along the inner wall of the second trench to the second surface of the epitaxial layer.

6. The laser array according to claim 2, wherein The first electrode comprises: A first contact layer, the first contact layer being located on the first surface of the epitaxial layer; A first pad, electrically connected to the first contact layer.

7. The laser array according to claim 6, wherein, Further comprising: A third trench, the third trench penetrating at least one layer of the epitaxial layer; The first pad extends into the third trench.

8. The laser array according to claim 7, characterized in that, Further comprising: A second passivation layer, the second passivation layer being at least partially located on an inner wall of the third trench and extending along the inner wall of the third trench to the first surface of the epitaxial layer and the top of the first contact layer.

9. The laser array according to claim 7, wherein The projection of the third trench and the first trench in a direction perpendicular to the first surface at least partially overlaps.

10. The laser array according to claim 7, wherein The projection of the third trench and the first trench in a direction perpendicular to the first surface does not overlap with each other.

11. The laser array according to claim 1, wherein, The plurality of second electrodes includes a second electrode, and the second electrode comprises: A second contact layer, the second contact layer being located on the second surface of the epitaxial layer; A second pad, electrically connected to the second contact layer, and the second pad being at least partially located on the second surface of the epitaxial layer.

12. The laser array according to claim 1, characterized in that, Further comprising: A transparent substrate, located on the first surface side of the epitaxial layer and covering the first electrode and the first surface of the epitaxial layer.

13. The laser array according to claim 12, wherein Further comprising: An adhesion layer, the adhesion layer being located between the first surface of the epitaxial layer and the transparent substrate.

14. The laser array according to claim 1, characterized in that, The light-emitting cavity further comprises an oxide layer.

15. A method for forming a laser array, characterized in that Comprising: Providing a substrate; Epitaxially growing an epitaxial layer on the substrate, the epitaxial layer having a first surface and a second surface, and the second surface being located between the substrate and the first surface; Forming a first electrode at least partially located on the first surface of the epitaxial layer; Removing the substrate; Forming a plurality of second electrodes at least partially located on the second surface of the epitaxial layer; Forming a first isolation structure for providing electrical isolation between at least some adjacent second electrodes among the plurality of second electrodes.

16. The method for forming a laser array according to claim 15, wherein The first electrode formed at least partially on the first surface of the epitaxial layer includes: Form a first contact layer in a partial region of the first surface of the epitaxial layer.

17. The method for forming a laser array according to claim 16, wherein After forming the first electrode formed at least partially on the first surface of the epitaxial layer and before removing the substrate, it further includes: Form a third trench penetrating at least one layer of the epitaxial layer; Oxidize at least one layer of the epitaxial layer on both sides of the third trench to form an oxide layer; Form a second passivation layer on a partial region of the first surface of the epitaxial layer and on the top of the first contact layer, and the second passivation layer extends to the inner wall of the third trench.

18. The method for forming a laser array according to claim 17, wherein The formation of the first electrode formed at least partially on the first surface of the epitaxial layer further includes: Form a first pad electrically connected to the first contact layer on the first surface of the epitaxial layer, and the first pad extends into the third trench.

19. The method for forming a laser array according to claim 15, wherein After removing the substrate and before forming a plurality of second electrodes formed at least partially on the second surface of the epitaxial layer, it further includes: Provide a transparent substrate and an adhesion layer; Bond the bottom of the adhesion layer to the first surface side of the epitaxial layer and at least partially cover the first electrode and the first surface of the epitaxial layer; Bond the transparent substrate to the top of the adhesion layer.

20. The method for forming a laser array according to claim 17, wherein, The formation of a plurality of second electrodes formed at least partially on the second surface of the epitaxial layer includes: Form a second contact layer in a partial region of the second surface of the epitaxial layer.

21. The method for forming a laser array according to claim 20, wherein The formation of a first isolation structure for providing electrical isolation between at least some adjacent second electrodes among the plurality of second electrodes includes: Form a first trench between at least some adjacent second contact layers, and the first trench penetrates at least one layer of the epitaxial layer; Form a first passivation layer on the inner wall of the first trench, and the first passivation layer extends along the inner wall of the first trench to the second surface of the epitaxial layer.

22. The method for forming a laser array according to claim 21, wherein It further includes: Form a through hole penetrating the epitaxial layer; The formation of the first electrode formed at least partially on the first surface of the epitaxial layer further includes: Extend the first electrode to the second surface along the through hole; The formation of a plurality of second electrodes formed at least partially on the second surface of the epitaxial layer further includes: Form a second pad electrically connected to the second contact layer.

23. The method for forming a laser array according to claim 22, wherein, Before extending the first electrode to the second surface along the through hole and forming a second pad electrically connected to the second contact layer, it further includes: Form the first passivation layer on the inner wall of the through hole.

24. The method for forming a laser array according to claim 22, wherein Before extending the first electrode to the second surface along the through hole and forming a second pad electrically connected to the second contact layer, it further includes: Form a second trench between the through hole and some of the second electrodes among the plurality of second electrodes, and the second trench penetrates at least one layer of the epitaxial layer; Form the first passivation layer in the second trench, and the first passivation layer extends along the inner wall of the second trench to the second surface of the epitaxial layer.

25. The method for forming a laser array according to claim 24, wherein The projection of the third trench and the first trench in the direction perpendicular to the first surface at least partially overlaps.

26. The method for forming a laser array according to claim 24, wherein The projection of the third trench and the first trench in the direction perpendicular to the first surface does not overlap.

27. The method for forming a laser array according to claim 15, wherein Remove the substrate by adopting at least one of the following methods: Mechanical grinding process; Chemical mechanical planarization process; Wet etching process; Back grinding process.

28. A lidar, characterized in that, Comprising: A laser emitter for emitting a light beam into the environment, the laser emitter comprising a laser array as described in any one of claims 1 to 14; A detector for receiving the echo after the light beam is reflected by one or more objects in the environment and generating a signal; A processor coupled to the detector for receiving and processing the signal to obtain at least one of the distance and reflectivity of the object.

Images