Laser array, forming method thereof and laser radar

Abstract

The invention provides a laser array and a forming method thereof, and a laser radar, and the laser array comprises a plurality of light-emitting cavities which comprise a plurality of epitaxial layers; at least part of the first electrode is located on the first surface of the epitaxial layer; the plurality of second electrodes are at least partially positioned on the second surface of the epitaxial layer; and the first isolation structure is used for providing electrical isolation between at least part of adjacent second electrodes in the plurality of second electrodes. According to the technical scheme, the light-emitting area of the light-emitting area of the laser array can be increased, and the detection performance of the laser radar is further improved.

Description

Technical Field

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

[0002] A lidar is an active remote sensing device that uses a laser as a light source and adopts optoelectronic detection technology, and has wide applications in scenarios such as autonomous driving. Lasers can have various different types, such as Vertical-Cavity Surface-Emitting Lasers (VCSELs), distributed feedback lasers, etc.

[0003] Multiple lasers can form a laser array. To achieve the emission control of the laser array, the laser array needs to achieve two-dimensional addressability. For example, in the two-dimensional dimensions (row and column dimensions) of the laser array, specific lasers are selected and activated so that specific lasers in the laser array emit light. Summary of the Invention

[0004] Embodiments of the present disclosure provide a laser array, a method for forming the same, and a lidar, which can increase the light-emitting area of the light-emitting region of the laser array, and thus improve the detection performance of the lidar.

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

[0006] Multiple light-emitting cavities, where the light-emitting cavity includes multiple epitaxial layers;

[0007] A first electrode, where at least a part of the first electrode is located on a first surface of the epitaxial layer;

[0008] Multiple second electrodes, where at least a part of the multiple second electrodes is located on a second surface of the epitaxial layer;

[0009] A first isolation structure, where the first isolation structure is used to provide electrical isolation between at least some adjacent second electrodes among the multiple second electrodes.

[0010] Optionally, the first isolation structure includes:

[0011] A first trench, where the first trench is located between at least some adjacent second electrodes, and the first trench penetrates at least one layer of the multiple epitaxial layers;

[0012] A first passivation layer, at least a part of which is 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 to the second surface of the epitaxial layer through the through-hole.

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

[0017] The laser array further includes:

[0018] A second isolation structure, including the part where the first passivation layer extends to the inner wall of the through-hole.

[0019] Optionally, the laser array further includes:

[0020] A second trench, which is located between the through-hole and at least some of the second electrodes among the plurality of second electrodes, and the second trench penetrates at least one layer of the plurality of epitaxial layers;

[0021] At least a part of the first passivation layer is located on the 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, which is located on the first surface of the epitaxial layer;

[0024] A first pad, which is electrically connected to the first contact layer.

[0025] Optionally, the laser array further includes:

[0026] A third trench, which penetrates at least one layer of the plurality of epitaxial layers;

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

[0028] Optionally, the laser array further includes:

[0029] A second passivation layer, which 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 and the top of the first contact layer.

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

[0031] Optionally, the projection of the third trench in a direction perpendicular to the first surface does not overlap with the projection of the first trench.

[0032] Optionally, the second electrode includes:

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

[0034] A second pad, electrically connected to the second contact layer, at least a part of the second pad being located on the second surface of the epitaxial layer.

[0035] Optionally, the laser array further includes:

[0036] A transparent substrate, located on a first surface side of the epitaxial layer and covering the first electrode and the first surface of the epitaxial layer.

[0037] Optionally, the laser array further includes:

[0038] An adhesion layer, the adhesion layer being 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, including:

[0041] Providing a substrate;

[0042] Epitaxially growing a plurality of epitaxial layers on the substrate, the epitaxial layer having a first surface and a second surface, the second surface being 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] Forming a first isolation structure for providing electrical isolation between at least some adjacent second electrodes among the plurality of second electrodes.

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

[0048] Forming a first contact layer in a partial region of the first surface of the epitaxial layer.

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

[0050] Forming a third trench penetrating at least one layer of the plurality of epitaxial layers;

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

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

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

[0054] Forming a first pad on the first surface of the epitaxial layer and electrically connected to the first contact 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 on the second surface of the epitaxial layer, it further includes:

[0056] Providing a transparent substrate and an adhesion 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] Bonding the transparent substrate to the top of the adhesion layer.

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

[0060] Forming a second contact layer on a partial area of the second surface of the epitaxial layer.

[0061] Optionally, forming the 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 some adjacent second contact layers, and the first trench penetrates at least one layer of the plurality of epitaxial layers;

[0063] Forming 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.

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

[0065] Forming a through hole penetrating the epitaxial layer;

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

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

[0068] Forming the plurality of second electrodes at least partially on the second surface of the epitaxial layer further includes:

[0069] Form a second pad electrically connected to the second contact layer.

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

[0071] Form the first passivation layer on the inner wall of the via hole.

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

[0073] Form a second trench between the via hole and some of the second electrodes among the plurality of second electrodes, the second trench penetrating at least one layer of the plurality of epitaxial layers;

[0074] 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.

[0075] Optionally, at least a part of the projection of the third trench and the first trench in a direction perpendicular to the first surface overlaps.

[0076] Optionally, the projection of the third trench and the first trench in a direction perpendicular to the first surface does 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] Correspondingly, the present disclosure further provides a lidar, comprising:

[0083] One or more laser emitters for emitting light beams into the environment, the laser emitter comprising the laser array as described in any one of the foregoing examples;

[0084] One or more detectors for receiving the echo after the light beam is reflected by one or more objects in the environment and generating a signal;

[0085] A processor, coupled to the detector, for receiving and processing the signal to obtain at least one of the distance and reflectivity information of the object.

[0086] Using the laser array in the present disclosure, the laser array may include a plurality of light-emitting cavities, the light-emitting cavities may include a plurality of epitaxial layers, the epitaxial layers having a first surface and a second surface, wherein a first electrode may be at least partially located on the first surface of the epitaxial layer. By disposing at least a portion of a plurality of second electrodes 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 some adjacent second electrodes among the plurality of second electrodes, the area of the non-light-emitting region on the first surface of the epitaxial layer can be reduced, the light-emitting region area of the laser array can be increased, and by disposing the second electrodes on the second surface of the epitaxial layer, second electrodes with larger sizes can be designed, the resistance of the second electrodes can be reduced, the influence brought by the resistance can be reduced, which is beneficial to current injection into each light-emitting cavity, and the detection performance of the lidar can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 A schematic structural diagram showing an example of a laser array;

[0088] Figure 2 A schematic structural diagram showing an example of a laser array in an embodiment of the present disclosure;

[0089] Figure 3 A schematic structural diagram showing an example of a laser array in an embodiment of the present disclosure;

[0090] Figures 4 to 15 Schematic structural diagrams corresponding to the steps in a method for forming an example of a laser array in an embodiment of the present disclosure;

[0091] Figures 16 to 24 Schematic structural diagrams corresponding to the steps in a method for forming another example of a laser array in an embodiment of the present disclosure;

[0092] Figure 25 A schematic structural diagram showing an example of a lidar in an embodiment of the present disclosure. DETAILED DESCRIPTION

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

[0094] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to 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 specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0095] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "in accordance with", "connected" and "connected to" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection: it may be a mechanical connection, an electrical connection or a connection that allows mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0096] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0097] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0098] Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the embodiments described herein are only for the purpose of illustrating and explaining the present invention and are not intended to limit the present invention.

[0099] In the light-emitting scheme of a vertical-cavity surface-emitting laser (VCSEL) array, one design is that the anodes of some lasers in the two-dimensional VCSEL array are interconnected, and the cathodes are isolated from each other; alternatively, the cathodes of some lasers are interconnected, and the anodes are isolated from each other. For example, the anodes of the lasers in the same row of the array are interconnected, the cathodes are isolated from each other, the anodes of the lasers in the same column are isolated from each other, and the cathodes are interconnected. By selectively turning on specific anode electrodes and specific cathode electrodes, two-dimensional addressability of the VCSEL array can be achieved.

[0100] In some embodiments, two-dimensional addressability of the VCSEL array may include: achieving independent control of at least some of the lasers in the two-dimensional VCSEL array.

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

[0102] The difficulty in the manufacturing process of the two-dimensional addressability scheme of the VCSEL array lies in the need to maintain the isolation between different channels to reduce or avoid crosstalk between lasers. In the current manufacturing process, both the anode electrode and the cathode electrode are disposed on the light-emitting surface of the light-emitting region, which will occupy a part of the area of the light-emitting surface. And in order to achieve isolation between different lasers, a trench structure also needs to be etched on the light-emitting surface, and the trench structure will also occupy a part of the area of the light-emitting surface.

[0103] To enable those skilled in the art to better understand the prior art, the following takes the structure of a laser array as an example for illustration.

[0104] See Figure 1 The schematic structural diagram of an example of a laser array shown, asFigure 1 As shown, the laser array includes a plurality of semiconductor lasers, and the plurality of semiconductor lasers share a substrate 10. Each semiconductor laser further includes an epitaxial layer located above the substrate 10.

[0105] For any semiconductor laser, it includes an n-type contact layer 11 located above the substrate 10, a plurality of cathode electrodes 12 and a plurality of epitaxial layers 13 located on the n-type contact layer 11, a plurality of anode electrodes 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, trenches are also formed in the epitaxial layer 13, and the p-type contact layer 15 also extends into the trenches. And after forming the trenches, the active region can be oxidized along the lateral part of the inner wall of the trenches to form an oxide layer.

[0107] Figure 1 The schematic laser array can adopt a way of emitting light from the front (for example, Figure 1 the upper side surface in...). Since both the cathode electrode 12 and the anode electrode 14 are also located on the front of the semiconductor laser, this already occupies a part of the area of the light-emitting surface. And to prevent the current of the semiconductor laser from propagating in the lateral direction as shown in, for example, Figure 1 electrical isolation needs to be performed between adjacent semiconductor lasers.

[0108] For example, continuing to refer to Figure 1 , the laser array further includes an isolation structure 16 for realizing electrical isolation between semiconductor lasers.

[0109] And when etching the deep trench structure to form the isolation structure 16, the position of the cathode electrode (as shown by the circle in Figure 1 ) also needs to be reserved. Therefore, the area occupied by the isolation structure 16 is relatively large, reducing the duty cycle of the light-emitting surface on the light-emitting channel.

[0110] Embodiments of the present disclosure provide a laser array. At least part of the first electrode can be located on the first surface of the epitaxial layer. By disposing at least part of a plurality of second electrodes 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 some adjacent second electrodes among the plurality of second electrodes, the area of the non-light-emitting region on the first surface of the epitaxial layer can be reduced, the light-emitting region area of the laser array can be increased, and by disposing 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 influence brought by the resistance, is beneficial to the current injection into each light-emitting cavity, and can improve the detection performance of the lidar.

[0111] 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 embodiments of the present disclosure will be described below with reference to the accompanying drawings.

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

[0113] As an example, the isolation structure may be formed by etching from the first surface and the second surface of the epitaxial layer respectively to achieve cathode isolation of each light-emitting cavity, so as to increase the duty cycle of the light-emitting surface.

[0114] For example, referring to Figure 2 the schematic structural diagram of an example of a laser array in the embodiments of the present disclosure shown, the laser array may include a vertical cavity surface emitting laser (VCSEL) array.

[0115] In some examples, as Figure 2 shown, the laser array may include: a plurality of light-emitting cavities, the light-emitting cavities may include a plurality of epitaxial layers 102; a first electrode 112, at least a part of the first electrode 112 may be located on the first surface of the epitaxial layer 102; a plurality of second electrodes 128, at least a part of the plurality of second electrodes 128 may be located on the second surface of the epitaxial layer 102; a first isolation structure 122, the first isolation structure 122 may be used to provide electrical isolation between at least some adjacent second electrodes among the plurality of second electrodes.

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

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

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

[0119] It should be noted that in some embodiments of the present disclosure, the epitaxial layer 102 including the nDBR layer is used as an example for illustration. In some 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. Among them, 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, and the active layers include one or more quantum well (QW) layers.

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

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

[0125] In some other embodiments, the second surface of the epitaxial layer 102 may be used as the light-emitting surface, that is, the laser 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. Among them, 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 be a part of the semiconductor device connected to the external circuit. It has good electrical conductivity and can form a good ohmic contact with the semiconductor material.

[0128] In some examples, the first contact layer 104 may be composed of a metal (such as a metal with good electrical conductivity such as gold, silver, copper, etc.) or a highly doped semiconductor material.

[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 a 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 can serve as the first electrode 112 of the laser array. Through the first electrode 112, the connection between the laser array and the external circuit can be achieved.

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

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

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

[0136] In other examples, the materials of the first pad 110 and the first contact layer 104 can be different. The present disclosure does not limit the materials of the first pad 110 and the first contact layer 104, as long as the two can play the role of electrical connection.

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

[0138] As an example, continue to refer to Figure 2 , the laser array can also include a third trench, and the third trench can penetrate at least one layer of the plurality of epitaxial layers 102.

[0139] In some examples, as Figure 2 shown, the third trench can sequentially penetrate the pDBR layer, the QW layer, and at least part of the nDBR layer.

[0140] In some other examples, the third trench can penetrate the pDBR layer and at least part of the QW layer in the plurality of epitaxial layers 102.

[0141] In this case, continue to refer to Figure 2 , the first pad 110 can also extend into the third trench. In some examples, continue to refer to Figure 2 , the laser array can also include: a second passivation layer 108, and 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 is in direct contact with the epitaxial layer 102. Since both the first pad 110 and the epitaxial layer 102 are conductive, by forming the second passivation layer 108 on the inner wall of the third trench, electrical isolation between the first pad 110 in the third trench and the epitaxial layer 102 can be achieved, reducing or preventing the current generated by the laser from transmitting in a direction parallel to the first surface, and improving the light-emitting performance of the laser array.

[0143] In some examples, when forming the third trench, with continued reference to Figure 1 , an oxide layer 106 can also be formed by at least partially laterally oxidizing the quantum well layer on the inner wall of the third trench.

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

[0145] In some embodiments, to reduce the occupied area of the non-light-emitting region on the first surface of the epitaxial layer, the second electrode can be located on the second surface of the epitaxial layer, so that the occupied area of the light-emitting surface on the first surface can be increased, and the duty cycle of the light-emitting surface can be increased.

[0146] As an example, as Figure 2 shown, the second electrode 128 can include: a second contact layer 118 and a second pad 126. Among them, the second contact layer 118 can be located on the second surface of the epitaxial layer 102; the second pad 126 can be electrically connected to the second contact layer 118, and at least part of the second pad 126 is located on the second surface of the epitaxial layer 102.

[0147] In some disclosed embodiments, the second contact layer 118 can be the part of the semiconductor device connected to the external circuit. It has good electrical conductivity and can form a good ohmic contact with the semiconductor material.

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

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

[0150] In some examples, the second pad 126 can be composed of a 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 the second electrode 128 of the laser array. Through the second electrode 128, the connection between the laser array and the external circuit can be achieved.

[0152] And since the second electrode is disposed 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 influence caused by the resistance, facilitate the current injection into each light-emitting cavity, and improve the detection performance of the lidar.

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

[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 play an electrical connection role.

[0155] In some embodiments, with continued reference to Figure 2 , the laser array may further include: a transparent substrate 116, located on the first surface side of the epitaxial layer 102 and covering the first surface of the first electrode 112 and the epitaxial layer 102.

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

[0157] By providing a transparent substrate on the first surface side and covering the first electrode and the first surface of the epitaxial layer with the transparent substrate, the mechanical strength of the laser array can be enhanced without affecting the light emission of the laser.

[0158] In some examples, to enhance the adhesion between the transparent substrate 116 and the first surface side of the epitaxial layer 102, the laser array may further include an adhesion layer 114, and 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, and the top of the adhesion layer 114 is bonded to the bottom of the transparent substrate 116.

[0160] In some embodiments, with continued reference to Figure 2 , the first isolation structure 122 may include: a first trench G12 and a first passivation layer 120, wherein the first trench G12 may be located between at least some adjacent second electrodes 128, and the first trench G12 penetrates at least one layer of the plurality of epitaxial layers 102; the first passivation layer 120 is at least partially located on the inner wall of the first trench G12 and extends 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 carbon oxynitride, silicon boron carbonitride, etc.

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

[0163] By forming the first passivation layer in the first trench, a partial region of the second surface of the epitaxial layer, and the 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 further enabling independent control of the formed semiconductor laser.

[0164] In some embodiments, the projection 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 Figure 2 , the projection of the first trench G12 and the third trench in a direction perpendicular to the first surface of the epitaxial layer 102 overlaps, and by making the projections of the two overlap, the depth of etching the first trench from the second surface to the first surface can be reduced, reducing the process difficulty.

[0166] In some examples, to reduce the packaging difficulty and cost, continuing to refer to Figure 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 further expose the bottom of the first electrode 112.

[0168] Referring to Figure 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, the first electrode 112 can be formed on the first surface and the second surface of the epitaxial layer 102, such 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 both the first electrode 112 and the second electrode 128 include portions located on the second surface of the epitaxial layer 102, and the laser array can be directly attached to an external circuit (for example, a laser driving chip or a laser driving circuit), realizing the electrical connection between the laser array and the external circuit, and reducing the packaging difficulty and cost.

[0170] When extending the first electrode 112 to the second surface of the epitaxial layer 102 through the via hole T11, considering 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, the second trench G13 may be located between the via hole T11 and at least some of the second electrodes among the plurality of second electrodes 128, and the second trench G13 may penetrate at least one layer of the plurality of epitaxial layers 102.

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

[0173] At least a part of the first passivation layer 120 may be located on the 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. Among them, the first passivation layer 120 and the second trench G13 serve as the second isolation structure 124.

[0174] In this way, when both the first electrode 112 and the second electrode 128 are located on the second surface of the epitaxial layer 102, by providing the second isolation structure 124, lateral (e.g., the horizontal direction in the attachment) electrical insulation between the first electrode 112 and the second electrode 128 can be provided, reducing or avoiding the occurrence of short - circuit problems, thereby promoting the flow of current through the epitaxial layer 102 and improving the light - emitting efficiency of the laser array. Figure 2 In the horizontal direction) electrical insulation, reducing or avoiding the occurrence of short - circuit problems, thereby promoting the flow of current through the epitaxial layer 102 and improving the light - emitting efficiency of the laser array.

[0175] In some examples, at least a part of the first passivation layer 120 may extend to the inner wall of the via hole T11 to achieve electrical isolation between the first electrode 112 in the via hole T11 and the epitaxial layer 102, reducing or preventing the transmission of current in a direction parallel to the first surface, and further improving the light - emitting efficiency of the laser array.

[0176] As described above, Figure 2 Only as an example to illustrate the structure of the laser array in the present disclosure. And, although Figure 2 is described for VCSEL, but in combination with Figure 2 the described exemplary embodiments, the laser array may further include vertical - emission laser diodes and / or other types of vertical - emission devices.

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

[0178] For example, see Figure 3Schematic structural diagram of another example of a laser array in the disclosed embodiments shown.

[0179] Referring to Figure 3 , compared with Figure 2 the embodiment shown, Figure 3 the projections of the first trench G12 and the third trench shown in

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

[0181] In some examples, in the 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 each other, so that when etching the epitaxial layer 302 to form the first trench G42, the influence on the oxide layer 406 can be reduced or avoided, and the quality of the formed oxide layer 406 can be improved.

[0182] As described above, Figure 3 only as an example to illustrate the structure of the laser array in the present disclosure. And although Figure 3 it is described for VCSEL, but in combination with Figure 3 the exemplary embodiments described, the laser array may further include vertical-emitting laser diodes and / or other types of vertical-emitting devices.

[0183] 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 will be described below with reference to the accompanying drawings.

[0184] See Figures 4 to 15 the schematic structural diagrams corresponding to the steps in a method for forming an example of a laser array in the disclosed embodiments shown.

[0185] Referring to Figure 4 , provide a substrate 300, and the substrate 300 can provide a process platform for forming other epitaxial structures subsequently.

[0186] In some examples, the substrate 300 can be formed of various semiconductor materials. For example, III-V semiconductors (such as gallium arsenide (GaAs), indium gallium arsenide (InGaAs), indium phosphide (InP), etc.); or, IV semiconductors (such as silicon (Si), silicides, etc.).

[0187] In some examples, various materials can be used to dope the substrate 300 to form an n-type substrate or a p-type substrate.

[0188] For example, through doping treatment, 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.

[0189] Referring to Figure 5 , a plurality of epitaxial layers 302 are epitaxially grown on the substrate 300.

[0190] In some examples, the epitaxial layer 302 may include one or more n-doped epitaxial layers, where 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 may 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 (GaAs) and may be thicker than each of the alternating nDBR layers, so as to reduce the etching difficulty of the n+-doped buffer layer.

[0193] It should be noted that in the embodiments of the present disclosure, Figure 5 and the subsequent drawings are exemplified by the epitaxial layer 302 including the nDBR layer. In some 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 the n-doped epitaxial layer. Among them, 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, the epitaxial layer 302 may include one or more active layers, and the active layer includes 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 above 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, where 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 the side 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 the light-emitting surface, that is, the laser can be emitted from the side of the first surface SF1.

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

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

[0204] In some embodiments, the first electrode 312 may be formed in the following manner:

[0205] As Figure 6 shown, a first contact layer 304 is formed in a partial region of the first surface of the epitaxial layer 302.

[0206] In some examples, the first contact layer 304 may be formed by a physical vapor deposition process. For example, the first contact layer 304 is formed by 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 the 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 the top of the first surface of a part of the epitaxial layer 302.

[0208] In some embodiments of the present disclosure, the first contact layer 304 may be a part of the semiconductor device connected to the external circuit, which 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 composed of a metal (such as metals with good electrical conductivity like gold, silver, copper, aluminum, etc.) or a highly doped semiconductor material.

[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 thatFigure 6 The number and distribution positions of the first contact layers shown in the figure are only for illustrative purposes, and are used to illustrate that a film layer for connecting to an external circuit can be formed on the top of the epitaxial layer.

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

[0214] As an example, as Figure 7 shown, a third trench G31 is formed that penetrates at least one layer of the multiple epitaxial layers 302.

[0215] In some examples, as Figure 7 shown, the third trench G31 can be formed by sequentially penetrating the pDBR layer, QW layer, and at least part of the nDBR layer in the multiple epitaxial layers 302.

[0216] In some other examples, the third trench G31 can be formed by penetrating the pDBR layer and at least part of the QW layer in the multiple epitaxial layers 302.

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

[0218] For example, an anti-reflection coating and a photoresist layer are sequentially formed on the epitaxial layer, wherein the photoresist layer has a pattern opening that exposes part of the anti-reflection coating. Using the photoresist layer as a mask, a plasma etching process is used to sequentially etch the first anti-reflection coating and the epitaxial layer along the pattern opening, removing the epitaxial layer exposed by the pattern opening, thereby forming the third trench G31.

[0219] Continuing to refer to Figure 7 , after forming the third trench G31, at least one layer of the epitaxial layer 302 on both sides of the third trench G31 can be oxidized to form an oxide layer 306.

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

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

[0222] By forming the oxide layer 306, current can be guided through the oxidation 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] Referring to Figure 8 , a second passivation layer 308 is formed on a partial area of the first surface of the epitaxial layer 302 and on top of the first contact layer 304, and the second passivation layer 308 can extend to the inner wall of the third trench G31.

[0224] In some examples, the second passivation layer can be formed by a Plasma Enhanced Chemical Vapor Deposition (PECVD) process. By selecting the plasma enhanced chemical vapor deposition process, the second passivation layer can be uniformly covered on the surface to be deposited, can cover the third trench, thereby improving the performance and reliability of the device, and the formed second passivation layer can be firmly attached to the substrate and is not easily peeled off or fallen off, thereby improving the stability and reliability of the device.

[0225] In some examples, the second passivation layer can also be formed by an Atomic layer deposition (ALD) process, and the embodiments of the present disclosure do not impose any restrictions on the manner of forming the second passivation layer.

[0226] In some examples, the material for forming the second passivation layer can include a dielectric material. For example, the dielectric material can be a silicon-containing dielectric material, such as: silicon nitride, silicon oxynitride, silicon carbon oxynitride, silicon carbonitride boron, etc.

[0227] In some examples, to enable the first pad formed subsequently to be electrically connected to the first contact layer, as Figure 8 shown, when forming the second passivation layer 308, at least a part of the top of the first contact layer 304 can also be exposed by the second passivation layer 308.

[0228] By forming the second passivation layer in the third trench, a partial area of the first surface of the epitaxial layer, and on top of the first contact layer, electrical isolation between adjacent first contact layers can be achieved, and the light-emitting performance of the laser array can be improved.

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

[0230] In some examples, the first pad 310 can be formed by 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 an electric field and a magnetic field. When the electron beam hits the surface of the first pad material layer, its energy can be converted into heat energy to heat the first pad material layer to the evaporation temperature. The first pad material layer can contact the substrate surface and condense to form the first pad.

[0232] Through controlled energy and focus, the deposition process can be controlled to form a first pad 310 as shown in Figure 9 electrically connected to the first contact layer 304 and extending into the third trench G31.

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

[0234] In some examples of the present disclosure, the first pad 310 and the first contact layer 306 can serve as the first electrode 312 of the laser array. Through the first electrode 312, the connection between the laser array and the external circuit can be achieved.

[0235] In some examples, the first electrode 312 can serve as the anode of the laser array, and the subsequently formed second electrode 328 (as shown in Figure 15 ) can serve as the 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. At this time, 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 for forming the first pad 310 and the first contact layer 306 can be the same.

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

[0239] In some embodiments, to reduce the occupied area of the non-light-emitting region on the first surface of the epitaxial layer, the second electrode can be located on the second surface of the epitaxial layer, so as to increase the occupied area of the light-emitting surface on the first surface and increase the duty cycle of the light-emitting surface.

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

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

[0242] In some examples, at least one of a mechanical grinding process, a chemical mechanical planarization process, a wet etching process, and a back grinding process can be used to at least partially remove the substrate 300.

[0243] In some embodiments, the entire substrate can be removed. In other embodiments, a part of the substrate can be removed. In some examples of the present disclosure, the example of removing the entire substrate is used for illustration.

[0244] By removing the substrate, the thickness of the laser array can be reduced, which facilitates the formation of 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] Referring to Figure 11 , providing a transparent substrate 316 and an adhesion layer 314.

[0247] Bond the bottom of the adhesion layer 314 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] Bond the transparent substrate 316 to the top of the adhesion layer 314.

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

[0250] In some examples, the adhesion layer 314 can be a viscous substance. For example, the adhesion layer 314 can be a viscous glue.

[0251] In some examples, the transparent substrate 316 and the adhesion layer 314 are transparent to light in the working band of the semiconductor laser.

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

[0253] With the solution of the above example, 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 with the transparent substrate, the mechanical strength of the laser array can be enhanced without affecting the light emission of the laser, which is beneficial to subsequent processes on the second surface of the epitaxial layer. On the other hand, by providing an adhesion 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 successively forming an adhesion layer and a transparent substrate 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, refer to Figure 12 , a second contact layer 318 is formed in a partial region on the second surface of the epitaxial layer 302.

[0256] In some examples, the second contact layer 318 can be formed by a physical vapor deposition process. For example, the second contact layer 318 is formed by an electron beam (E-beam) evaporation deposition process.

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

[0258] In some disclosed embodiments, the second contact layer 318 can be a part of the semiconductor device connected to the external circuit, which has good electrical conductivity and can form a good ohmic contact with the semiconductor material.

[0259] In some examples, the second contact layer 318 can be composed of a 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 can 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 between at least some adjacent second electrodes can be provided.

[0263] As an example, as Figure 13 and Figure 14 shown, the method of forming the first isolation structure 322 can include:

[0264] See Figure 13 , a first trench G32 is formed between at least some of the adjacent second contact layers 318, and the first trench G32 can penetrate at least one of the plurality of epitaxial layers 302.

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

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

[0267] In Figure 13 , the projection 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 projection of the first trench G32 and the third trench G31 overlap in the direction perpendicular to the first surface of the epitaxial layer 302, the depth of the third trench etched from the first surface to the second surface can be reduced, and the process difficulty can be reduced.

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

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

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

[0272] In some examples, continuing to refer to Figure 13 , when forming the first trench G32, part of the second passivation layer 308 can also be removed to expose the bottom of the first electrode 312.

[0273] In some examples, the projection of the first trench and the third trench in the direction perpendicular to the first surface of the epitaxial layer overlap, and by making the projections of the two overlap, the depth of the first trench etched from the second surface to the first surface can be reduced, and the process difficulty can be reduced. Refer to Figure 14, a first passivation layer 320 is formed on the inner wall of the first trench G32, and 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 can be formed by a plasma enhanced chemical vapor deposition process or an atomic layer deposition process. For the formation process, reference can be made to the description of the second passivation layer.

[0275] In some examples, the material for forming the first passivation layer can include a dielectric material. For example, the dielectric material can be a silicon-containing dielectric material, such as silicon nitride, silicon oxynitride, silicon carbon oxynitride, silicon carbonitride boron, etc.

[0276] In some examples, to enable the subsequently formed second pad to be electrically connected to the second contact layer, as Figure 14 shown, when forming the first passivation layer 320, at least part of the top of the second contact layer 318 can also be exposed by the first passivation layer 320.

[0277] By forming the first passivation layer on the first trench, a partial region of the second surface of the epitaxial layer, and the top of the second contact layer, electrical isolation between adjacent second contact layers can be achieved, reducing or preventing current from flowing between adjacent light-emitting cavities, enabling separate control of some second electrodes, and thus enabling independent control of the formed semiconductor laser.

[0278] In some examples, to reduce the packaging difficulty and cost, continuing to refer to Figure 13 , the method for forming the laser array can further include: forming a through hole T31 passing through the epitaxial layer 302.

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

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

[0281] Correspondingly, referring to Figure 15 , when forming the first electrode 312 on the first surface of the epitaxial layer 302, it can further include: extending the first electrode 312 along the through hole T31 to the second surface of the epitaxial layer 302.

[0282] Through the through hole T31, the first electrode 312 can be formed on the first surface and the second surface 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.

[0283] Moreover, both the first electrode 312 and the second electrode 328 include portions located on the second surface of the epitaxial layer 302, and the laser array can be directly attached to an external circuit (e.g., a laser driver chip or a laser driver circuit), achieving electrical connection between the laser array and the external circuit, and reducing the packaging difficulty and cost.

[0284] In some examples, with continued reference to Figure 15 , when forming the second electrode 328 on the second surface of the epitaxial layer 302, it may further include:

[0285] Forming a second pad 326 electrically connected to the second contact layer 318.

[0286] In some examples, the second pad 326 may be formed by an electron beam deposition process, and the formation process may refer to the description of the first pad.

[0287] In some examples, the second pad 326 may be composed of a metal or a highly doped semiconductor material.

[0288] In some examples of the present disclosure, the second pad 326 and the second contact layer 318 may serve as the second electrode 328 of the laser array, and through the second electrode 328, the connection between the laser array and the external circuit can be achieved.

[0289] By disposing the second electrode on the second surface of the epitaxial layer, the size of the second electrode can be enlarged, the resistance of the second electrode can be reduced, the influence brought by the resistance can be reduced, which is beneficial to the current injection into each light-emitting cavity, and the detection performance of the lidar can be improved.

[0290] It should be noted that, in some examples of the present disclosure, the materials for forming the second pad 326 and the second contact layer 318 may be the same.

[0291] In other examples, the materials for forming the second pad 326 and the second contact layer 318 may be different. The present disclosure does not limit the materials for forming the second pad 326 and the second contact layer 318, as long as the two can play an electrical connection role.

[0292] When extending the first electrode 312 to the second surface of the epitaxial layer 302 through the via T31, considering that the first electrode 312 and the second electrode 328 may be directly connected, resulting in a short-circuit problem of the laser array.

[0293] Based on this, when both the first electrode 312 and the second electrode 328 are located on the second surface of the epitaxial layer 302, a second isolation structure 324 for realizing electrical isolation between the first electrode 312 and the second electrode 328 may further be formed.

[0294] As an example, with continued reference toFigure 14 Before extending the first electrode 312 to the second surface of the epitaxial layer 302 along the through hole T31 and forming the second pad 326 electrically connected to the second contact layer 318, it may further include:

[0295] Form a second trench G33 between the through hole T31 and some of the second electrodes 328 among the plurality of second electrodes, and the second trench G33 may penetrate at least one layer of the plurality of epitaxial layers 302.

[0296] Form the first passivation layer 320 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.

[0297] Among them, the method of forming the second trench G33 can refer to the foregoing examples.

[0298] When forming the second trench G33, the first passivation layer 320 may also be formed in the second trench G33, and the first passivation layer 320 and the second trench G33 may jointly serve as the second isolation structure 324.

[0299] In this way, when both the first electrode 312 and the second electrode 328 are located on the second surface of the epitaxial layer 302, by providing the second isolation structure 324, lateral (e.g., the horizontal direction in the attachment Figure 14 among them) electrical insulation between the first electrode 312 and the second electrode 328 can be provided, reducing or avoiding the occurrence of short - circuit problems, thereby promoting the current to flow through the epitaxial layer 302 and improving the light - emitting efficiency of the laser array.

[0300] In some examples, continue to refer to Figure 14 Before extending the first electrode 312 to the second surface of the epitaxial layer 302 along the through hole T31 and forming the second pad 326 electrically connected to the second contact layer 318, it may further include:

[0301] Form the first passivation layer 320 on the inner wall of the through hole T31, and the first passivation layer 320 can be used to achieve electrical isolation between the first electrode 312 located in the through hole T31 and the epitaxial layer 302.

[0302] In the foregoing disclosed example solutions, the example illustration is carried out in the way of forming the first trench, then forming the through hole, finally forming the second trench, and extending the first passivation layer to the through hole and the second trench.

[0303] In some other examples, the first trench, the through hole, and the second trench can also be formed in the same step, and the first passivation layer is 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, the second contact layer is formed, and the first electrode is extended to the second surface along the through hole.

[0304] In some other examples, the first trench and the second trench can also be formed in the same step, the through hole is 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 extends to the second surface of the epitaxial layer. In a further step, the second contact layer is formed, and the first electrode is extended to the second surface along the through hole.

[0305] See Figures 16 to 24 the schematic structural diagrams corresponding to the steps in the formation method of another example of the laser array in the embodiments of the present disclosure shown.

[0306] In this embodiment, the manner of forming the substrate and the epitaxial layer on the substrate can refer to the description of the foregoing examples.

[0307] Refer to Figures 16 to 19 , form the first electrode 412 at least partially located on the first surface of the epitaxial layer 402 (see Figure 19 ).

[0308] In some embodiments, the first electrode 412 can be formed in the following manner, including:

[0309] As Figure 16 shown, form the first contact layer 404 in a partial region on the first surface of the epitaxial layer 402.

[0310] In some examples, the first contact layer 404 can be formed by a physical vapor deposition process. For example, the first contact layer 404 is formed by an electron beam evaporation deposition process.

[0311] In some other examples, the process of forming the first contact layer 404 can include: depositing and forming a first contact material layer on the top of the first surface of the epitaxial layer 402 (for example, it can 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 can expose a part of the top of the first surface of the epitaxial layer 402.

[0312] In some embodiments, the first contact layer 404 can be a part of the semiconductor device connected to the external circuit, which has good electrical conductivity and can form a good ohmic contact with the semiconductor material.

[0313] In some examples, the first contact layer 404 may be composed of a metal or a highly doped semiconductor material.

[0314] In some examples, the first contact layer 404 may be a p-type contact layer.

[0315] In some other examples, the first contact layer 404 may also be an n-type contact layer.

[0316] It should be noted that Figure 16 The number and distribution position of the first contact layers shown in are only for illustrative purposes, and are used to illustrate that a film layer for connecting to an external circuit can be formed on the top of the epitaxial layer.

[0317] In some embodiments, to achieve isolation between multiple first electrodes formed by the first pad and the first contact layer subsequently, and electrical isolation between the first electrodes located in the epitaxial layer and the epitaxial layer, after forming the first contact layer at least partially on the first surface of the epitaxial layer, a second passivation layer for electrical isolation may also be formed.

[0318] As an example, as Figure 17 shown, a third trench G41 is formed through at least one layer of the multiple epitaxial layers 402.

[0319] In some examples, as Figure 17 shown, the third trench G41 may be formed by sequentially penetrating the pDBR layer, QW layer, and at least part of the nDBR layer in the multiple epitaxial layers 402.

[0320] In some other examples, the third trench G41 is formed by penetrating the pDBR layer and at least part of the QW layer in the multiple epitaxial layers 402; or the third trench G41 may be formed by penetrating at least part of the pDBR layer in the multiple epitaxial layers 402.

[0321] In some embodiments, the third trench G41 may be formed by using a plasma etching process (for example, inductively coupled plasma reactive ion etching).

[0322] For example, an anti-reflection coating and a photoresist layer are sequentially formed on the epitaxial layer, wherein the photoresist layer has a graphic opening exposing part of the anti-reflection coating. Using the photoresist layer as a mask, a plasma etching process is used to sequentially etch the first anti-reflection coating and the epitaxial layer along the graphic opening, and the epitaxial layer exposed by the graphic opening is removed, thereby forming the third trench G41.

[0323] In some examples, as Figure 17 shown, there is a case where multiple third trenches G41 are formed between two adjacent first contact layers 104.

[0324] Continue to refer to Figure 17 After forming the third trench G41, the quantum well layers on both sides of the third trench G41 can be oxidized to form an oxide layer 406.

[0325] As an example, the oxide layer 406 can be formed by a wet oxidation process.

[0326] By forming the oxide layer 406, the current can be guided through the oxidation 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.

[0327] Next, refer to Figure 18 A second passivation layer 408 is formed on a partial region of the first surface of the epitaxial layer 402 and the top of the first contact layer 404. The second passivation layer 408 can extend to the inner wall of the third trench G41.

[0328] In some examples, the second passivation layer can be formed by a plasma enhanced chemical vapor deposition (PECVD) process. By selecting the plasma enhanced chemical vapor deposition process, the second passivation layer can be uniformly covered on the surface to be deposited, can cover the third trench, thereby improving the performance and reliability of the device, and the formed second passivation layer can be firmly attached to the substrate, thereby improving the stability and reliability of the device.

[0329] In some examples, the second passivation layer can also be formed by an atomic layer deposition process. The embodiments of the present disclosure do not impose any restrictions on the manner of forming the second passivation layer.

[0330] In some examples, the material for forming the second passivation layer can include a dielectric material. For example, the dielectric material can be a silicon-containing dielectric material, such as: silicon nitride, silicon oxynitride, carbon oxynitride, silicon boron carbonitride, etc.

[0331] In some examples, to enable the first pad formed subsequently to be electrically connected to the first contact layer, as Figure 18 shown, when forming the second passivation layer 408, the second passivation layer 408 can also expose at least a part of the top of the first contact layer 404.

[0332] By forming the second passivation layer in the third trench, a partial region 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, and thus the light emitting performance of the laser array can be improved.

[0333] Refer to Figure 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 can extend into the third trench G41.

[0334] In some examples, the first pad 410 can be formed by an electron beam deposition process, for example:

[0335] Generate a high-energy electron beam through an electron gun, and guide and accelerate the electron beam to the surface of the first pad material layer through an electric field and a magnetic field. When the electron beam hits the surface of the first pad material layer, its energy can be converted into heat energy to heat the first pad material layer to the evaporation temperature. The first pad material layer can contact the substrate surface and condense to form the first pad.

[0336] By controlling the energy and focus, the deposition process can be controlled to form a first pad 410 as shown in Figure 19 electrically connected to the first contact layer 404 and extending into the third trench G41.

[0337] In some examples, the first pad 410 can be composed of a metal or a highly doped semiconductor material.

[0338] In some examples of the present disclosure, the first pad 410 and the first contact layer 406 can serve as the first electrode 412 of the laser array. Through the first electrode 412, the connection between the laser array and the external circuit can be realized.

[0339] In some examples, the first electrode 412 can serve as the anode of the laser array, and the subsequently formed second electrode 428 can serve as the cathode of the laser array.

[0340] In some examples, the first electrode 412 can serve as the cathode of the laser array, and the subsequently formed second electrode 428 can serve as the anode of the laser array. At this time, the first contact layer 404 is an n-type contact layer, and the second contact layer 418 can be a p-type contact layer.

[0341] 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 can be the same.

[0342] In some other examples, the materials forming the first pad 410 and the first contact layer 406 can 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 play an electrical connection role.

[0343] In some embodiments, to reduce the occupied area of the non-light-emitting region on the first surface of the epitaxial layer, the second electrode can be located on the second surface of the epitaxial layer, so that the occupied area of the light-emitting surface on the first surface can be increased, and the duty ratio of the light-emitting surface can be increased.

[0344] In some examples, after removing the substrate, the second electrode can be formed on the second surface of the epitaxial layer.

[0345] As an example, refer to Figure 20 , the substrate 400 can be removed so as to form a second electrode 426 on the second surface of the epitaxial layer 402 (refer to Figure 24 ).

[0346] In some examples, at least one of a mechanical grinding process, a chemical mechanical planarization process, a wet etching process, and a back grinding process can be adopted to remove the substrate 400.

[0347] Among them, all of the substrate can be removed, or only a part of the substrate can be removed. In some examples of the present disclosure, an example of removing all of the substrate is used for illustrative purposes.

[0348] By removing the substrate, the thickness of the laser array can be reduced, which is convenient for forming other structures on the second surface of the epitaxial layer, such as a second electrode, a first passivation layer, etc.

[0349] In some examples, after removing the substrate, 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:

[0350] Refer to Figure 21 , provide a transparent substrate 416 and an adhesion layer 414, bond the bottom of the adhesion layer 414 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 bond the transparent substrate 416 to the top of the adhesion layer 414.

[0351] In some examples, the transparent substrate 416 can be a sapphire substrate, and the laser emitted from the first surface side of the epitaxial layer 402 can be projected to the outside through the transparent substrate 416.

[0352] In some examples, the adhesion layer 414 can be a substance with adhesiveness. For example, the adhesion layer 314 can be an adhesive glue.

[0353] In some examples, the transparent substrate 416 and the adhesion layer 414 are transparent to light in the working wavelength band of the semiconductor laser.

[0354] In some other embodiments, other methods can also be adopted to form Figure 21 the structure shown. For example, the transparent substrate can be bonded to the top of the adhesion layer first, and then the bottom of the adhesion layer can be bonded to the first surface side of the epitaxial layer.

[0355] With the solution of the above example, 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 with the transparent substrate, the mechanical strength of the laser array can be enhanced without affecting the light emission of the laser, which is beneficial for subsequent processes on the second surface of the epitaxial layer. On the other hand, by providing an adhesion 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.

[0356] After successively forming the adhesion layer and the transparent substrate on the first surface side of the epitaxial layer, the adhesion layer and the transparent substrate can be used as a processing platform for subsequent epitaxial structures, and then a plurality of second electrodes can be formed on the second surface of the epitaxial layer.

[0357] As an example, refer to Figure 22 , a second contact layer 418 is formed in a partial region on the second surface of the epitaxial layer 402.

[0358] In some examples, the second contact layer 418 can be formed by a physical vapor deposition process. For example, the second contact layer 418 is formed by an electron beam evaporation deposition process.

[0359] In some disclosed embodiments, the second contact layer 418 can be a part of the semiconductor device connected to the external circuit, which has good conductivity and can form a good ohmic contact with the semiconductor material.

[0360] In some examples, the second contact layer 418 can be composed of a metal or a highly doped semiconductor material.

[0361] In some examples, the second contact layer 418 can be an n-type contact layer.

[0362] In some other examples, the second contact layer 418 can be a p-type contact layer.

[0363] In some embodiments, to achieve electrical isolation between at least some adjacent second electrodes, a first isolation structure for electrical isolation can be provided between at least some adjacent second electrodes.

[0364] As an example, as shown in Figure 23 and Figure 24 , the method of forming the first isolation structure 422 can include:

[0365] Refer to Figure 23 , a first trench G42 is formed between at least some adjacent second contact layers 418, and the first trench G42 penetrates at least one layer of the plurality of epitaxial layers 302.

[0366] In some examples, as shown in Figure 23As shown, the first trench G42 can be formed by penetrating the nDBR layer in the epitaxial layer 402.

[0367] In some examples, the 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 each other.

[0368] As an example, the first trench G42 can be formed between two adjacent third trenches G41 (see Figure 18 ).

[0369] 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 each other. In this way, the influence on the oxide layer 406 can be reduced or avoided, and the quality of the formed oxide layer 406 can be improved.

[0370] In some embodiments, the first trench G42 can be formed by using a plasma etching process (for example, inductively coupled plasma reactive ion etching).

[0371] For example, an anti-reflection coating and a photoresist layer are sequentially formed on the second surface of the epitaxial layer. Among them, the photoresist layer has a pattern opening exposing part of the anti-reflection coating. Using the photoresist layer as a mask, a plasma etching process is used to sequentially etch the first anti-reflection coating and the epitaxial layer along the pattern opening, and the epitaxial layer exposed by the pattern opening is removed, thereby forming the first trench G42.

[0372] In some examples, continuing to refer to Figure 23 , when forming the first trench G42, part of the second passivation layer 408 can also be removed to expose the bottom of the first electrode 412.

[0373] 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 making their projections overlap, the depth of etching the first trench from the second surface to the first surface can be reduced, and the process difficulty can be reduced.

[0374] Referring to Figure 24 , a first passivation layer 420 is formed on the inner wall of the first trench G42, and the first passivation layer 420 can extend along the inner wall of the first trench G42 to the second surface of the epitaxial layer 402.

[0375] In some examples, the first passivation layer can be formed by using a plasma enhanced chemical vapor deposition process or an atomic layer deposition process. The formation process can refer to the description of the formation process of the second passivation layer.

[0376] In some examples, the material forming the first passivation layer may include a dielectric material. For example, the dielectric material may be a silicon-containing dielectric material, such as silicon nitride, silicon oxynitride, silicon carbon oxynitride, silicon carbonitride boron, etc.

[0377] In some examples, to enable the subsequently formed second pad to be electrically linked to the second contact layer, as Figure 23 shown, when forming the first passivation layer 420, the first passivation layer 420 may also expose at least a part of the top of the second contact layer 418.

[0378] By forming the first passivation layer in the first trench, a partial region of the second surface of the epitaxial layer, and the top of the second contact layer, electrical isolation between adjacent second contact layers can be achieved, thereby enabling separate control of some of the second electrodes, and further enabling independent control of the formed semiconductor lasers.

[0379] In some examples, to reduce the packaging difficulty and cost, continuing to refer to Figure 23 , the method for forming the laser array may further include: forming a through hole T42 passing through the epitaxial layer 402.

[0380] In some examples, the manner of forming the through hole T42 may refer to the description of the first trench G42 in the foregoing examples.

[0381] In some examples, when forming the through hole T42, a part of the second passivation layer 408 may also be removed to expose the bottom of the first electrode 412.

[0382] Correspondingly, referring to Figure 24 , when forming the first electrode 412 on the first surface of the epitaxial layer 402, it may further include: extending the first electrode 412 along the through hole T42 to the second surface of the epitaxial layer 402.

[0383] By extending the first electrode 412 to the second surface of the epitaxial layer 402, such that both the first electrode 412 and the second electrode 426 are 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 driving chip or a laser driving circuit), realizing electrical connection between the laser array and the external circuit, and reducing the packaging difficulty and cost.

[0384] In some examples, continuing to refer to Figure 24 , when forming the second electrode 426 on the second surface of the epitaxial layer 402, it may further include:

[0385] forming a second pad 424 electrically connected to the second contact layer 418.

[0386] In some examples, the second pad 424 may be formed by an electron beam deposition process. For the specific formation process, reference may be made to the description of the first pad.

[0387] In some examples, the second pad 424 may be composed of a metal or a highly doped semiconductor material.

[0388] In some examples of the present disclosure, the second pad 424 and the second contact layer 418 as a whole may serve as the second electrode 426 of the laser array. Through the second electrode 426, the connection between the laser array and the external circuit can be achieved.

[0389] Since the second electrode is disposed 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 influence brought by the resistance, facilitate the current injection into each light-emitting cavity, and improve the detection performance of the lidar.

[0390] It should be noted that in some examples of the present disclosure, the materials for forming the second pad 424 and the second contact layer 418 may be the same.

[0391] In other examples, the materials for forming the second pad 424 and the second contact layer 418 may be different. The present disclosure does not limit the materials for forming the second pad 424 and the second contact layer 418, as long as the two can play an electrical connection role.

[0392] When extending the first electrode 412 to the second surface of the epitaxial layer 402 through the via 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 of the laser array.

[0393] Based on this, when both the first electrode 412 and the second electrode 426 are located on the second surface of the epitaxial layer 402, a second isolation structure for realizing electrical isolation between the second electrode 426 and the first electrode 412 may further be formed.

[0394] As an example, continue to refer to Figure 24 , before extending the first electrode 412 to the second surface of the epitaxial layer 402 along the via hole T42 and forming the second pad 424 electrically connected to the second contact layer 418, it may further include:

[0395] Forming a first passivation layer 420 between the via hole T42 and some of the second electrodes 426 among the plurality of second electrodes 426. The first passivation layer 420 may serve as the second isolation structure to realize electrical isolation between the second electrode 426 and the first electrode 412.

[0396] Thus, when both the first electrode 412 and the second electrode 426 are located on the second surface of the epitaxial layer 402, by providing the second isolation structure, lateral (e.g., horizontal direction as in Figure 24 ) electrical insulation between the first electrode 412 and the second electrode 426 can be provided, reducing or avoiding the occurrence of short - circuit problems, thereby promoting current flow through the epitaxial layer 402 and improving the light - emitting efficiency of the laser array.

[0397] In some examples, the first electrode 412 located on the inner wall of the through - hole T42 is in direct contact with the epitaxial layer 402. Since both the first electrode 412 and the epitaxial layer 402 are conductive, laser light may be transmitted in a direction parallel to the first surface.

[0398] In some examples, continuing to refer to Figure 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, it may further include:

[0399] Forming the first passivation layer 420 on the inner wall of the through - hole T42, and the first passivation layer 420 can be used for electrical isolation between the first electrode 412 located in the through - hole T42 and the epitaxial layer 402.

[0400] In the scheme of the foregoing disclosed examples, an example is described in the way of forming the first trench, then forming the through - hole, finally forming the second trench, and extending the first passivation layer to the through - hole.

[0401] In some other examples, the first trench and the through - hole can also be formed in the same step, and then the first passivation layer is formed in the same step. The first passivation layer can be located on the inner walls of the first trench and the through - hole and extend to the second surface of the epitaxial layer. Finally, the second contact layer is formed, and at the same time, the first electrode is extended along the through - hole to the second surface.

[0402] The above - mentioned disclosure provides explanations and descriptions, but is not intended to be exhaustive or limit the implementation to the exact form disclosed. Modifications and variations can be made according to the above - mentioned disclosure, or can be obtained from the practice of the implementation.

[0403] The number, arrangement, thickness, order, symmetry and / or the like of the layers shown in the above figure and / or described herein are provided as examples. In fact, the emitter array and / or the vertical emission device shown in the figure and / or described herein can be arranged in a different way from those shown in the figure and / or described herein.

[0404] Even if specific 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 embodiments. In fact, many of these features can be combined in ways not specifically recited in the claims and / or not disclosed in the disclosure. Although each dependent claim listed below may directly depend only on one claim, the disclosure of the various implementations includes the combination of each dependent claim with every other claim in the claim set.

[0405] Unless explicitly stated, any element, action, or instruction used herein should not be construed as critical or essential. Additionally, as used herein, the article "a" is intended to include one or more items and may be used interchangeably with "one or more".

[0406] In a specific implementation, the laser array in the above examples can be applied to various devices or apparatuses with detection functions.

[0407] As an example, as Figure 25 shown, the present disclosure also provides a lidar, and the lidar L0 may include:

[0408] A transmitting module TX0, including one or more laser emitters L01, configured to emit light beams into the environment, and the laser emitter L01 may include the laser array as described in any of the foregoing embodiments;

[0409] A receiving module RX0, including one or more detectors L02, configured to receive the echo after the light beam is reflected by one or more objects in the environment and generate a signal;

[0410] A processor ( Figure 25 not shown), coupled to the detector L02, configured to receive and process the signal to obtain at least one of the distance or reflectivity information of the object.

[0411] Next, referring to Figure 25 , as an example, the laser emitters L01 in the transmitting module TX0 may be arranged in a two-dimensional array, and the laser emitter L01 may include vertical-cavity surface-emitting lasers (VCSELs). As Figure 25 shown, the light emitted by the laser emitter L01 is shaped by an emission lens group (not shown) and then emitted from the lidar L0 in different directions to cover the field of view (FOV) of the lidar.

[0412] As an example, one or more detectors L02 in the receiving module RX0 may include at least one of an Avalanche Photon Diode (APD), a Single Photon Avalanche Diode (SPAD), and a Silicon Photo Multiplier (SiPM). They are arranged in a two-dimensional array and correspond to the arrangement of the laser emitter L01, so as to form a plurality of detection channels with the laser emitter L01 in the transmitting module TX0.

[0413] In some embodiments, each detection channel may include one laser emitter and one or more detectors, or may be composed of one or more lasers and one detector, or include multiple laser emitters and multiple detectors. The optical signals emitted by the lasers in the same detection channel can be received by the detectors in the same detection channel after being reflected by an object. The sub-fields of view of all the detection channels together constitute the FOV of the entire lidar.

[0414] The processor may be any chip, device, or equipment with data processing capabilities, such as a microcontroller, a Field Programmable Gate Array (FPGA), a single-core or multi-core processor, etc. The specific hardware structure is not limited in the embodiments of the present disclosure.

[0415] Although the present disclosure is disclosed as above, the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A laser array, characterized in that, Comprising: Multiple light-emitting cavities, where each light-emitting cavity includes multiple epitaxial layers; A first electrode, where the first electrode is at least partially located on a first surface of the epitaxial layer; Multiple second electrodes, where the multiple second electrodes are at least partially located on a second surface of the epitaxial layer; A first isolation structure, where the first isolation structure is used to provide electrical isolation between at least some adjacent second electrodes among the multiple second electrodes.

2. The laser array according to claim 1, wherein The first isolation structure includes: A first trench, where the first trench is located between at least some adjacent second electrodes, and the first trench penetrates at least one layer of the multiple epitaxial layers; A first passivation layer, at least partially located on the 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, It further includes: A through hole passing through 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 includes: 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 It further includes: A second trench, where the second trench is located between the through hole and at least some second electrodes among the multiple second electrodes, and the second trench penetrates at least one layer of the multiple epitaxial layers; The first passivation layer is at least partially located on the 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 includes: A first contact layer, where the first contact layer is 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 It further includes: A third trench, where the third trench penetrates at least one layer of the multiple epitaxial layers; The first pad extends into the third trench.

8. The laser array according to claim 7, characterized in that, It further includes: A second passivation layer, where the second passivation layer 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 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, characterized in that, The second electrode includes: A second contact layer, where the second contact layer is located on the second surface of the epitaxial layer; A second pad, electrically connected to the second contact layer, and the second pad is at least partially located on the second surface of the epitaxial layer.

12. The laser array according to claim 1, wherein It further includes: 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, characterized in that, It further includes: An adhesion layer, where the adhesion layer is located between the first surface of the epitaxial layer and the transparent substrate.

14. The laser array according to claim 1, wherein, The light-emitting cavity further includes an oxide layer.

15. A method for forming a laser array, characterized in that, Including: Providing a substrate; Epitaxially growing multiple epitaxial layers on the substrate, where the epitaxial layer has a first surface and a second surface, and the second surface is 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 multiple 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 multiple 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 plurality of epitaxial layers; Perform an oxidation treatment on 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 the 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 the 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 plurality of epitaxial layers; 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 the 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 plurality of epitaxial layers; 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 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: One or more laser emitters for emitting a light beam into the environment, the laser emitter comprising the laser array according to any one of claims 1 to 14; One or more detectors 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 information of the object.

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