A semiconductor laser and a lidar

Abstract

The present application discloses a semiconductor laser and a lidar. The laser includes a semiconductor stack structure, which is divided into two regions, namely, a first region including an array of double heterojunction structures sharing a first-type doped semiconductor layer, and a second region with high insulation and high thermal conductivity properties disposed around the first region. A thermoelectric cooling device is directly disposed on the second region to directly dissipate heat from the array of double heterojunction structures efficiently. For the lidar adopting the above semiconductor laser in its emission component, since its emission component achieves more efficient and direct heat dissipation, it can maintain the best working state in a high-temperature environment.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and particularly to a semiconductor laser and a lidar. Background Art

[0002] The Vertical-Cavity Surface-Emitting Laser (VCSEL) is an advanced semiconductor laser. Its uniqueness lies in forming a resonant cavity in the vertical direction of the substrate and emitting laser light in the vertical direction. The VCSEL has significant advantages such as small temperature drift, low threshold, easy fiber coupling, low power consumption, and better dynamic single-mode performance, showing great potential in application scenarios such as automotive lidar, face recognition, and 3D sensing.

[0003] However, the working environment of the VCSEL in automotive lidar is relatively harsh. When the working environment temperature reaches a certain level, the optical power of the VCSEL will rapidly decline. This is because the performance of the VCSEL deteriorates with the increase in temperature, and its thermosensitive characteristics make it difficult to maintain the best working state in a high-temperature environment.

[0004] Therefore, how to reduce the working temperature of the VCSEL is an issue that urgently needs attention and solution currently. Summary of the Invention

[0005] The purpose of this application is to provide a semiconductor laser and a lidar, which can improve the above problems.

[0006] The embodiments of this application are implemented as follows:

[0007] In a first aspect, this application provides a semiconductor laser, which includes a semiconductor stack structure and a thermoelectric cooling device;

[0008] The semiconductor stack structure includes a first region and a second region surrounding the first region. The first region is provided with an array of double heterojunction structures sharing a first-type doped semiconductor layer. The second region is subjected to ion implantation to form an insulating and heat-conducting part, and the insulating and heat-conducting part has thermal contact with the array of double heterojunction structures;

[0009] The thermoelectric cooling device is disposed in the second region and is configured to perform energy exchange on the insulating and heat-conducting part.

[0010] It can be understood that in the present application, ion implantation is performed on the second region to enhance its thermal conductivity, forming a heat-conducting region, and then a thermoelectric cooling device is directly disposed on the heat-conducting region for heat dissipation. Compared with the prior art in which the thermoelectric cooling device is attached to the back surface of the substrate where the double heterojunction structure array is located, since the thermoelectric cooling device is closer to each heat-generating double heterojunction structure, the heat dissipation effect is more direct and significant.

[0011] In an alternative embodiment of the present application, at least one channel surrounding the first region is provided in the second region, and the thermoelectric cooling device is disposed in the channel and / or the thermoelectric cooling device is disposed outside the channel. It can be understood that after opening the channel in the second region and disposing the thermoelectric cooling device in the channel, the thermoelectric cooling device is closer to the first region that generates heat, and the region overlapping with the second region is larger, which is more conducive to the heat dissipation effect.

[0012] In an alternative embodiment of the present application, the thermoelectric cooling device includes P-type thermoelectric elements and N-type thermoelectric elements alternately arranged along the current direction of the thermoelectric cooling device, and adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically connected by a conductive heat dissipation member to form a thermocouple structure.

[0013] It can be understood that taking the N-type thermoelectric element as an example, it may include a first end and a second end arranged oppositely, and there is a temperature difference between the first end and the second end; the conductive heat dissipation member in contact with the first end is configured to perform heat exchange on the first end, and the conductive heat dissipation member in contact with the second end is configured to perform heat exchange on the second end. The situation of the P-type thermoelectric element is the same as that of the N-type thermoelectric element, which will not be elaborated here. Further, the DC current passing from the N-type thermoelectric element to the P-type thermoelectric element will cool the conductive heat dissipation member sandwiched between them, and the DC current passing from the P-type thermoelectric element to the N-type thermoelectric element will heat the conductive heat dissipation member sandwiched between them.

[0014] In an alternative embodiment of the present application, the thermocouple structures are connected end to end and arranged along the edge contour of the double heterojunction structure array; and / or the thermocouple structures are connected end to end and cover the second region in a preset path.

[0015] It can be understood that the thermocouple structures are connected end to end and arranged along the edge contour of the double heterojunction structure array, which can reduce the number of thermocouple structures as much as possible under the condition of satisfying the heat dissipation of the first region surrounded by the thermocouple structures, thereby reducing the cost of the thermoelectric cooling device. In addition, although the number of thermocouple structures increases when the thermocouple structures are connected end to end and cover the second region in a preset path, the heat transfer efficiency of the second region is improved because the thermocouple structures cover the second region.

[0016] In an alternative embodiment of the present application, the thermocouple structure includes: a first thermocouple structure formed by electrically connecting the adjacent P-type thermoelectric element and the N-type thermoelectric element through a conductive heat dissipation member covering the same-side surfaces of both, wherein two adjacent conductive heat dissipation members are disposed on opposite surfaces of the same thermoelectric element. It can be understood that the above first thermocouple structure is a traditional thermocouple structure. The working principle of the traditional thermocouple structure is based on the Seebeck effect, that is, a closed loop is composed of two different thermoelectric elements. When the temperatures of the two joints are different, an electromotive force is generated in the loop. The magnitude of the electromotive force is related to the temperature difference. The temperature difference can be determined by measuring the electromotive force. Its technical advantages are remarkable. The structure is simple, composed of two thermoelectric elements and connecting components, and is easy to manufacture and install; the measurement range is wide, and it can adapt to different temperature environments; the response speed is fast, and it can quickly sense temperature changes; and the stability is good, and the performance can be maintained stable during long-term use, providing a reliable guarantee for temperature measurement.

[0017] In an alternative embodiment of the present application, the thermocouple structure includes: a second thermocouple structure formed by electrically connecting the adjacent P-type thermoelectric element and the N-type thermoelectric element through a conductive heat dissipation member clamped therebetween. It can be understood that compared with the traditional thermocouple structure, the second thermocouple structure uses smaller-sized thermoelectric elements but can achieve the same heat dissipation effect. This improvement enables more thermoelectric elements to be arranged in the same space, thereby significantly increasing the heat dissipation density.

[0018] In an alternative embodiment of the present application, in the second thermocouple structure, at least one conductive heat dissipation member extends toward the light-emitting body to form a first heat dissipation disc; at least one conductive heat dissipation member extends in a direction away from the light-emitting body to form a second heat dissipation disc; two adjacent conductive heat dissipation members extend in different directions. It can be understood that in addition to the area in contact with the thermoelectric element, the conductive heat dissipation member can also extend outward. Whether it extends toward the light-emitting body or in a direction away from the light-emitting body, the heat dissipation area of the conductive heat dissipation member can be increased, thereby achieving a better heat dissipation effect. In addition, two adjacent conductive heat dissipation members extending in different directions can prevent the extended parts of the two adjacent conductive heat dissipation members from restricting each other on the same side and blocking each other's extension dimensions. By adopting a scheme of extending in upper and lower layers respectively, the space can be utilized more fully to achieve the effect of maximizing the extension area.

[0019] In an alternative embodiment of the present application, in the second thermocouple structure, the P-type thermoelectric element and / or the N-type thermoelectric element are deposited on the first-type doped semiconductor layer by a vapor deposition process. It can be understood that by depositing the P-type thermoelectric element and / or the N-type thermoelectric element on the first-type doped semiconductor layer through the vapor deposition process, the bonding stability between the thermoelectric refrigeration device and the double heterojunction structure is enhanced.

[0020] In an alternative embodiment of the present application, the thermoelectric refrigeration device further includes at least one protective plate that covers the second thermocouple structure and / or the first thermocouple structure, and the protective plate is bonded to the second region by a gold-gold bonding method. It can be understood that on the one hand, the protective plate can play a certain packaging and protection role for each thermocouple structure, and on the other hand, it can also be fixed to the first-type doped semiconductor layer by a gold-gold bonding method, enhancing the bonding stability between the thermoelectric refrigeration device and the double heterojunction structure.

[0021] In an alternative embodiment of the present application, the double heterojunction structure array is grown on a substrate layer; each double heterojunction structure includes the first-type doped semiconductor layer, the active layer, and the second-type doped semiconductor layer stacked thereon, and a second chip electrode is provided on the second-type doped semiconductor layer; a first chip electrode is provided on the side of the substrate layer facing away from the double heterojunction structure array, and the first chip electrode is connected to the first-type doped semiconductor layer through the substrate layer.

[0022] In an alternative embodiment of the present application, in the double heterojunction structure, a confinement ring is provided on one side of the active layer close to the first-type doped semiconductor layer and / or on one side close to the second-type doped semiconductor layer, and the confinement ring is arranged around the light-emitting region of the active layer and is configured to confine the current conduction of the double heterojunction structure.

[0023] In an alternative embodiment of the present application, the first-type doped semiconductor layer is a semiconductor layer doped with group V / III elements, and the second-type doped semiconductor layer is a semiconductor layer doped with group III / V elements;

[0024] The ion implantation material in the second region includes at least one of the following substances:

[0025] H + 、O ⁺ 、N⁺、Ar⁺.

[0026] In an alternative embodiment of the present application, the channel in the second region sequentially penetrates the second-type doped semiconductor layer, the active layer, and exposes a part of the surface of the first-type doped semiconductor layer.

[0027] In an alternative embodiment of the present application, the thermoelectric refrigeration device is disposed on the side of the second-type doped semiconductor layer in the second region facing away from the substrate layer; and / or, the thermoelectric refrigeration device is located on the light-emitting direction side of the double heterojunction structure array.

[0028] In an alternative embodiment of the present application, the double heterojunction structure array includes at least one of the following:

[0029] At least two double heterojunction structures arranged in an axisymmetric or centrosymmetric manner;

[0030] Seven double heterojunction structures arranged in axial symmetry or central symmetry.

[0031] In an alternative embodiment of the present application, the edge profile of the double heterojunction structure array includes at least one of the following:

[0032] The edge profile of the double heterojunction structure array is an axially symmetric polygon;

[0033] The edge profile of the double heterojunction structure array is a centrally symmetric polygon.

[0034] It can be understood that arranging the double heterojunction structure array in axial symmetry or central symmetry is beneficial to uniformly dissipate heat from each of the double heterojunction structures therein.

[0035] In a second aspect, the present application provides a lidar, including a transmitting component and a receiving component; the transmitting component employs the semiconductor laser as described in any one of the above first aspects. It can be understood that the transmitting component of the lidar employs the above semiconductor laser. By directly arranging a thermoelectric refrigeration device in the region of the semiconductor layer with high thermal conductivity, the transmitting component of the lidar achieves more efficient and direct heat dissipation, thereby being able to maintain the best working state under high temperature or harsh environments. This design not only improves the performance stability of the lidar but also helps to extend its service life. Therefore, the lidar of the present application exhibits higher reliability and better performance in application scenarios such as vehicle-mounted, face recognition, and 3D sensing. Beneficial effects

[0036] The present application proposes a semiconductor laser, which includes a semiconductor stack structure. The semiconductor stack structure is subdivided into two regions, namely, a first region of a double heterojunction structure array that constitutes a common first-type doped semiconductor layer and a second region surrounding it with a higher ion implantation concentration and different doping substances. The high ion implantation concentration enables the second region to have better thermal conductivity. The thermoelectric refrigeration device is directly arranged on this second region with high thermal conductivity to directly dissipate heat from the double heterojunction structure array efficiently. Compared with the prior art in which the thermoelectric refrigeration device is attached to the back of the substrate where the double heterojunction structure array is located, the present application realizes more direct and effective heat dissipation by directly arranging the thermoelectric refrigeration device in the second region with high doping concentration. This design not only improves the heat dissipation efficiency but also helps to maintain the best working state of the semiconductor laser, especially performing well under high temperature or harsh environments.

[0037] The present application also provides a lidar, including a transmitting component and a receiving component; the transmitting component uses the semiconductor laser as described above. It can be understood that since the transmitting component of the lidar uses the above semiconductor laser, by directly arranging a thermoelectric cooling device in the region of the semiconductor layer with high thermal conductivity, the transmitting component of the lidar achieves more efficient and direct heat dissipation, and thus can maintain the best working state under high temperature or harsh environments. This design not only improves the performance stability of the lidar, but also helps to extend its service life. Therefore, the lidar of the present application exhibits higher reliability and better performance in application scenarios such as vehicle-mounted, face recognition, and 3D sensing.

[0038] To make the above objects, features, and advantages of the present application more obvious and understandable, the following specifically gives optional embodiments and, in conjunction with the attached drawings, the detailed description is as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can be obtained based on these drawings.

[0040] Figure 1 is a top view of a semiconductor laser provided by the present application;

[0041] Figure 2 is Figure 1 an AA' sectional view of the semiconductor laser shown;

[0042] Figure 3 is Figure 1 another AA' sectional view of the semiconductor laser shown;

[0043] Figure 4 is a top view of another semiconductor laser provided by the present application;

[0044] Figure 5 is a schematic sectional view of the first thermocouple structure provided by the present application;

[0045] Figure 6 is a schematic sectional view of the second thermocouple structure provided by the present application;

[0046] Figure 7 is a schematic sectional view of another thermocouple structure provided by the present application;

[0047] Figure 8 is a schematic view of the first thermocouple structure;

[0048] Figure 9It is a schematic diagram of the second thermocouple structure. Detailed implementation manners

[0049] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0050] In the first aspect, as Figure 1 and Figure 2 shown, the present application provides a semiconductor laser, which includes a semiconductor stack structure and a thermoelectric cooling device 20.

[0051] As Figure 1 shown, the semiconductor stack structure includes a first region 311 and a second region 312 surrounding the first region 311. The first region 311 constitutes an array of double heterojunction structures sharing a first-type doped semiconductor layer 31. The second region 312 is subjected to ion implantation to form an insulating and heat-conducting part (which can be referred to as 312), and there is a thermal contact between the insulating and heat-conducting part and the array of double heterojunction structures. The thermal contact can be interpreted as that the two are directly in physical contact or connection relationship, or can be interpreted as that the two are not directly in physical contact or connection relationship.

[0052] The thermoelectric cooling device 20 is disposed in the second region 312 and is configured to perform energy exchange on the insulating and heat-conducting part. The energy exchange mainly means that the heat in the insulating and heat-conducting part is exchanged out through the thermoelectric cooling device 20, or the heat is transmitted to the insulating and heat-conducting part through the thermoelectric cooling device. In this way, the dynamic control of heating and cooling can be realized according to the specific working conditions of the device.

[0053] In an optional embodiment of the present application, the array of double heterojunction structures includes at least one of the following: at least two double heterojunction structures arranged in an axisymmetric or centrosymmetric manner; seven double heterojunction structures arranged in an axisymmetric or centrosymmetric manner.

[0054] As Figure 1 shown, Figure 1 the array of double heterojunction structures 10 in

[0055] It can be understood that in the present application, ion implantation is performed on the second region 312 to form an insulating heat-conducting portion, so that the thermal conductivity of the region becomes stronger, forming a heat-conducting region, and then a thermoelectric cooling device 20 is directly arranged on the heat-conducting region for heat dissipation. Compared with the prior art in which the thermoelectric cooling device 20 is attached to the back side of the substrate where the double heterojunction structure array 10 is located, since the thermoelectric cooling device 20 is closer to each double heterojunction structure that generates heat, the heat dissipation effect is more direct and more significant.

[0056] refer to Figure 2 , the double heterojunction structure array 10 is grown on the substrate layer 32; each double heterojunction structure includes a first type doped semiconductor layer 31, an active layer 33 and a second type doped semiconductor layer 34 which are stacked to form a PN junction. When the carriers in the P region and the N region are injected into the active layer 33 under the action of the external circuit, the electrons and holes recombine in the active layer 33, release energy and generate photons. Since the cavity of the VCSEL is vertical, the photons are reflected multiple times between the reflectors formed by the two layers of doped semiconductor layers and are stimulated to be amplified to form coherent light. A second chip electrode 35 is arranged on the second type doped semiconductor layer 34; a first chip electrode 36 is arranged on the side of the substrate layer 32 away from the double heterojunction structure array 10, and the first chip electrode 36 is connected to the first type doped semiconductor layer 31 through the substrate layer 32. The first chip electrode 36 and the second chip electrode 35 are configured to apply a voltage to drive the injection of carriers and stimulate photon emission.

[0057] In an alternative embodiment of the present application, the first-type doped semiconductor layer 31 may be a semiconductor layer doped with group-V / III elements, and the second-type doped semiconductor layer 34 may be a semiconductor layer doped with group-III / V elements. The doping types of the first-type doped semiconductor layer 31 and the second-type doped semiconductor layer 34 are opposite. Exemplarily, the first-type doped semiconductor layer 31 may be doped with group-V elements to form an N-type semiconductor layer, and the second-type doped semiconductor layer 34 may be doped with group-III elements to form a P-type doped semiconductor layer. The substrate of the N-type doped semiconductor layer is usually made of semiconductor materials such as silicon (Si), germanium (Ge), or gallium arsenide (GaAs), and pentavalent elements such as phosphorus (P), arsenic (As), or antimony (Sb) are doped as dopants. These dopants can provide extra electrons, making the electron concentration in the N-type semiconductor much higher than the hole concentration. The substrate of the P-type doped semiconductor layer is made of the same semiconductor substrate, such as silicon, germanium, or gallium arsenide, but trivalent elements such as boron (B), aluminum (Al), or gallium (Ga) are doped. These dopants create holes in the semiconductor lattice, making the hole concentration in the P-type semiconductor higher than the electron concentration. The combination of N-type and P-type semiconductors forms a PN junction, which is the core structure of optoelectronic devices such as VCSELs. The second region 312 may have the same basic composition as the first region 311. For example, both include the first-type doped semiconductor layer 31, the active layer 33, and the second-type doped semiconductor layer 34. This method is the easiest to manufacture, that is, it is fabricated on the same epitaxial wafer. The difference is that the second region 312 additionally undergoes one or more ion implantation processes to form an insulating and thermally conductive portion including a high concentration of implanted ion concentration. The specific implanted substance and dose will be described later.

[0058] In an alternative embodiment of the present application, the optional ion implantation substance may be H + , O ⁺ , N⁺, Ar⁺, or at least one of them. Exemplarily, taking H + ion implantation as an example, the ion implantation process can be carried out under the main conditions of a dose ≥ 1×10¹ 7 ions / cm² and an energy of 150 keV. The implantation methods of other substances are similar. It can be understood that the method of achieving insulation and heat conduction through ion implantation can be understood with reference to the prior art. There is no special improvement in this part of the process in the present application, so it will not be further elaborated here.

[0059] In an alternative embodiment of the present application, reference may be made to Figure 3 . The channel 40 located in the second region 312 sequentially penetrates the second-type doped semiconductor layer 34 and the active layer 33, and exposes a part of the surface of the first-type doped semiconductor layer 31. When fabricating the channel 40, the ion implantation process can be carried out first, then the channel etching, and then the thermoelectric cooling device 20 is fabricated; or the ion implantation process is carried out first, the thermoelectric cooling device 20 is fabricated, and finally the channel etching is done.

[0060] As Figure 2 shown, the thermoelectric refrigeration device 20 is disposed on the side of the second-type doped semiconductor layer 34 in the second region 312 facing away from the substrate layer 32, and / or the thermoelectric refrigeration device 20 is located on the light-emitting direction side of the double heterojunction structure array.

[0061] Continuing to refer to Figure 2 , in the double heterojunction structure, a confinement ring 37 is disposed on the side of the active layer 33 close to the second-type doped semiconductor layer 34. The confinement ring 37 is disposed around the light-emitting region of the active layer 33 and is configured to confine the current conduction of the double heterojunction structure. After the double heterojunction structure is turned on, the current is confined by the confinement ring 37 and finally introduced into the light-emitting region of the double heterojunction structure to generate laser light in the light-emitting region of the double heterojunction structure. More specifically, in the embodiment of the present application, the confinement ring 37 has a confinement region surrounding the light-emitting region. The confinement region has a relatively high resistivity to limit the inflow of carriers into the middle region of the double heterojunction structure, and the refractive index of the confinement region is relatively low to perform lateral confinement on photons. The carrier and optical lateral confinement increase the density of carriers and photons in the active layer 33 and improve the efficiency of generating light in the active layer 33. Optionally, the above-mentioned confinement ring 37 may also be disposed on the side of the active layer 33 close to the first-type doped semiconductor layer 31, which will not be elaborated here.

[0062] As Figure 3 shown, at least one channel 40 surrounding the first region 311 is disposed in the second region 312.

[0063] As Figure 3 shown, the thermoelectric refrigeration device 20 is disposed in the channel 40. It can be understood that after the channel 40 is opened in the second region 312, the thermoelectric refrigeration device 20 is disposed in the channel 40, so that the thermoelectric refrigeration device 20 is closer to the first region 311 generating heat and has a larger overlapping area with the second region 312, which is more conducive to the heat dissipation effect. Optionally, the thermoelectric refrigeration device 20 may also be disposed outside the channel 40, which will not be elaborated here.

[0064] The thermoelectric refrigeration device includes P-type thermoelectric elements and N-type thermoelectric elements alternately arranged along the current direction of the thermoelectric refrigeration device. The adjacent P-type thermoelectric element and N-type thermoelectric element are electrically connected by a conductive heat sink to form a thermocouple structure. It can be understood that taking the N-type thermoelectric element as an example, it may include a first end and a second end arranged oppositely, and there is a temperature difference between the first end and the second end; the conductive heat sink in contact with the first end is configured to exchange heat with the first end, and the conductive heat sink in contact with the second end is configured to exchange heat with the second end. The situation of the P-type thermoelectric element is the same as that of the N-type thermoelectric element, which will not be elaborated here. Further, the DC current passing through from the N-type thermoelectric element to the P-type thermoelectric element will cool the conductive heat sink sandwiched between them, and the DC current passing through from the P-type thermoelectric element to the N-type thermoelectric element will heat the conductive heat sink sandwiched between them.

[0065] The above-mentioned alternate arrangement means that in the current direction of the thermoelectric refrigeration device, thermoelectric element combinations with the same structure are arranged in sequence. In these thermoelectric element combinations, the arrangement forms of the P-type thermoelectric elements and the N-type thermoelectric elements are the same. That is, along the current direction of the thermoelectric refrigeration device, the P-type thermoelectric elements are arranged first, and then the N-type thermoelectric elements; or, along the current direction of the thermoelectric refrigeration device, the N-type thermoelectric elements are arranged first, and then the P-type thermoelectric elements.

[0066] Optionally, the above-mentioned conductive heat sink can be made of copper or aluminum with good thermal conductivity and good electrical conductivity, which is conducive to the attachment of thermoelectric materials and the flow of current at low resistance. The above-mentioned thermoelectric materials can be selected from manganese silicide-based compounds (Mn-Si), magnesium silicide-based compounds (Mg-Si-Sn), skutterudite-based compounds (Co-Sb), half-Heusler-based compounds (Zr-Ni-Sn), and bismuth telluride-based compounds (Bi-Te).

[0067] In an alternative embodiment of the present application, as Figure 1 shown, the thermocouple structures are connected end to end and arranged along the edge contour of the double heterojunction structure array 10. It can be understood that the thermocouple structures are connected end to end and arranged along the edge contour of the double heterojunction structure array 10, which can reduce the number of thermocouple structures as much as possible under the condition of satisfying the heat dissipation of the thermocouple structures surrounding the first region 311, thereby reducing the cost of the thermoelectric refrigeration device 20.

[0068] In an alternative embodiment of the present application, as Figure 4As shown, the thermocouple structures are connected end to end and are arranged in a Z-shaped preset path to cover the second region 312. Optionally, in addition to the Z-shaped path, the preset path may also include other path schemes such as a meandering path that can cover the second region, which will not be elaborated here. It can be understood that although the number of thermocouple structures is increased when the thermocouple structures are connected end to end and arranged in a preset path to cover the second region 312, the heat transfer efficiency of the second region 312 is improved when the thermocouple structures cover the second region 312.

[0069] In an alternative embodiment of the present application, the edge profile of the double heterojunction structure array includes at least one of the following:

[0070] The edge profile of the double heterojunction structure array is an axisymmetric polygon;

[0071] The edge profile of the double heterojunction structure array is a centrosymmetric polygon.

[0072] It can be understood that arranging the double heterojunction structure array in an axisymmetric or centrosymmetric manner is beneficial to the uniform heat dissipation of each double heterojunction structure therein.

[0073] In an alternative embodiment of the present application, the thermocouple structure includes: a first thermocouple structure formed by electrically connecting an adjacent P-type thermoelectric element and an N-type thermoelectric element through a conductive heat dissipation member covering the same-side surfaces of both, wherein two adjacent conductive heat dissipation members are disposed on opposite surfaces of the same thermoelectric element. As Figure 5 shown, the first N-type thermoelectric element 51 is electrically connected to the first P-type thermoelectric element 71 on the left through the first conductive heat dissipation member 61 covering the top surface; the first N-type thermoelectric element 51 is electrically connected to other P-type thermoelectric elements on the right through the second conductive heat dissipation member 62 covering the bottom surface; the first P-type thermoelectric element 71 is electrically connected to other N-type thermoelectric elements on the left through the third conductive heat dissipation member 63 covering the bottom surface. It can be understood that the above first thermocouple structure is a traditional thermocouple structure. The working principle of the traditional thermocouple structure is based on the Seebeck effect, that is, two different thermoelectric elements form a closed loop. When the temperatures of the two junctions are different, an electromotive force is generated in the loop. The magnitude of the electromotive force is related to the temperature difference. The temperature difference can be determined by measuring the electromotive force. Its technical advantages are significant. The structure is simple, composed of two thermoelectric elements and connecting components, and is easy to manufacture and install; the measurement range is wide and can adapt to different temperature environments; the response speed is fast and can quickly sense temperature changes; and the stability is good, and the performance can be maintained stable during long-term use, providing a reliable guarantee for temperature measurement.

[0074] In an alternative embodiment of the present application, the thermocouple structure includes: an adjacent P-type thermoelectric element and an N-type thermoelectric element are electrically connected through a conductive heat dissipation member clamped therebetween, forming a second thermocouple structure. The above-mentioned clamping means that the conductive heat dissipation member is disposed between the P-type thermoelectric element and the N-type thermoelectric element. Specifically, the first surface of the conductive heat dissipation member facing the adjacent P-type thermoelectric element is physically connected to the P-type thermoelectric element and realizes electrical connection; the second surface of the conductive heat dissipation member facing the adjacent N-type thermoelectric element is physically connected to the N-type thermoelectric element and realizes electrical connection. As Figure 6 shown, the second N-type thermoelectric element 52 and the second P-type thermoelectric element 72 are electrically connected through a fourth conductive heat dissipation member 64 clamped therebetween; the second N-type thermoelectric element 52 and other P-type thermoelectric elements on the right are electrically connected through a fifth conductive heat dissipation member 65 clamped therebetween; the second P-type thermoelectric element 72 and other N-type thermoelectric elements on the left are electrically connected through a sixth conductive heat dissipation member 66 clamped therebetween. It can be understood that compared with the traditional thermocouple structure, the second thermocouple structure uses thermoelectric elements of smaller size but can achieve the same heat dissipation effect. This improvement enables more thermoelectric elements to be arranged in the same space, thereby significantly increasing the heat dissipation density.

[0075] In an alternative embodiment of the present application, in the second thermocouple structure, at least one conductive heat dissipation member extends towards the light-emitting body to form a first heat dissipation disc; at least one conductive heat dissipation member extends in a direction away from the light-emitting body to form a second heat dissipation disc; adjacent two conductive heat dissipation members extend in different directions. As Figure 7 shown, the fourth conductive heat dissipation member 64 between the second N-type thermoelectric element 52 and the second P-type thermoelectric element 72 extends in a first direction to form a first heat dissipation disc 81; the adjacent fifth conductive heat dissipation member 65 and sixth conductive heat dissipation member 66 extend in the opposite direction of the first direction to form a second heat dissipation disc 82. It can be understood that in addition to the area in contact with the thermoelectric element, the conductive heat dissipation member can also extend outward. Whether it extends towards the light-emitting body or in a direction away from the light-emitting body, it can increase the heat dissipation area of the conductive heat dissipation member, thereby achieving a better heat dissipation effect. In addition, adjacent two conductive heat dissipation members extending in different directions can prevent the extended parts of the adjacent two conductive heat dissipation members from restricting each other on the same side and blocking each other's extension dimensions. By adopting the scheme of extending in two upper and lower layers respectively, the space can be utilized more fully to achieve the effect of maximizing the extension area.

[0076] Optionally, as Figure 7 shown, insulating materials 90 are filled between adjacent conductive heat dissipation members, between the conductive heat dissipation member and the P-type thermoelectric element, and between the conductive heat dissipation member and the N-type thermoelectric element. It can be understood that the filling of the insulating material avoids the improper conduction of each element in the thermoelectric refrigeration device, ensures that the thermoelectric refrigeration device does not have a short-circuit fault, and maintains normal operation.

[0077] Optionally, the thermoelectric refrigeration device further includes a first protection plate and a second protection plate; the insulating material is an adhesive insulating glue, the first protection plate covers the first side of each thermocouple structure through the insulating glue, and the second protection plate covers the second side of each thermocouple structure through the insulating glue, with the first side and the second side being opposite to each other.

[0078] In an optional embodiment of the present application, in the second thermocouple structure, the P-type thermoelectric element and / or the N-type thermoelectric element are deposited on the first-type doped semiconductor layer 31 through a vapor deposition process. It can be understood that preparing the P-type thermoelectric element and / or the N-type thermoelectric element on the first-type doped semiconductor layer 31 through the vapor deposition process enhances the bonding stability between the thermoelectric refrigeration device 20 and the double heterojunction structure.

[0079] In the related preparation process of the present application, manganese silicide (MnSi) is prepared on a carrier through a vapor deposition process, specifically, by metal-organic chemical vapor deposition (MOCVD). Specifically, Mn(CO)5(SiCl3) is used as a single-source precursor, and a deposition reaction is carried out on the surface of a silica carrier at 400 °C and atmospheric pressure. This process is similar to the way of depositing the P-type thermoelectric element and / or the N-type thermoelectric element on a semiconductor layer through a vapor deposition process, enhancing the bonding stability between the deposit (i.e., silica-supported MnSi nanoparticles) and the carrier (silica). The finally obtained MnSi nanoparticles have a size of about 5 - 6 nm and are uniformly dispersed on the silica carrier, forming a manganese silicide layer with a thickness possibly in the nanoscale range (although not directly specified, it can be inferred from the nanoparticle size that the thickness of the layer formed by them may be in the range of 0.5 - 10 μm of the conventional vapor deposition layer thickness, and the specific value needs to be determined according to the actual deposition conditions).

[0080] In an optional embodiment of the present application, the thermoelectric refrigeration device 20 further includes at least one protection plate, the protection plate covers the second thermocouple structure and / or the first thermocouple structure, and the protection plate is bonded to the second region through a gold-gold bonding method. It can be understood that on the one hand, the protection plate can play a certain role in encapsulating and protecting each thermocouple structure, and on the other hand, it can be fixed to the first-type doped semiconductor layer 31 through the gold-gold bonding method, enhancing the bonding stability between the thermoelectric refrigeration device 20 and the double heterojunction structure.

[0081] In the traditional first thermocouple structure, adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically connected through a conductive heat dissipation member covering the top surface. Figure 8 It is a schematic structural diagram of a traditional thermocouple structure. When it is at the optimal cooling and heating power, the resistance of the conductive heat dissipation member satisfies the following formula: , where represents the resistance of the conductive heat dissipation member, that is, the parasitic resistance, represents the distance between the P-type thermoelectric element and the N-type thermoelectric element, represents the length value of the overlapping area between the P-type thermoelectric element or the N-type thermoelectric element and the conductive heat sink, represents the width values of the P-type thermoelectric element, the N-type thermoelectric element, and the conductive heat sink, represents the thickness of the conductive heat sink, represents the thicknesses of the P-type thermoelectric element and the N-type thermoelectric element, represents the resistivity of the conductive heat sink. When it is at the optimal cooling heat power, the resistance of the P-type / N-type thermoelectric element satisfies the following formula: , where, represents the resistance of the P-type / N-type thermoelectric element, represents the resistivity of the P-type / N-type thermoelectric element. Therefore, Figure 8 in the thermocouple structure shown, the ratio of the parasitic resistance to the resistance loss of the thermoelectric element satisfies the following formula: .

[0082] As Figure 9 shown in the second thermocouple structure, when it is at the optimal cooling heat power, the resistance of the conductive heat sink satisfies the following formula: , where, represents the resistance of the conductive heat sink, that is, the parasitic resistance, represents the thickness of the conductive heat sink, represents the length values of the P-type thermoelectric element and the N-type thermoelectric element, represents the width values of the P-type thermoelectric element, the N-type thermoelectric element, and the conductive heat sink, represents the thicknesses of the P-type thermoelectric element and the N-type thermoelectric element, represents the resistivity of the conductive heat sink. When it is at the optimal cooling heat power, the resistance of the P-type / N-type thermoelectric element satisfies the following formula: , where, represents the resistance of the P-type / N-type thermoelectric element, represents the resistivity of the P-type / N-type thermoelectric element. Therefore, Figure 9 in the thermocouple structure shown, the ratio of the parasitic resistance to the resistance loss of the thermoelectric element satisfies the following formula: .

[0083] In Figure 8 and Figure 9 when the material parameters of the P-type thermoelectric element, the N-type thermoelectric element, and the conductive heat sink are the same, to maintain the same ratio of resistance loss, that is, to satisfy , the thickness of the thermoelectric element needs to meet the following conditions: . Generally speaking, Figure 8 in , The values will all be designed to be larger than the Figure 9 value in , and at the same time, it is limited that the value is less than a preset threshold, that is, less than the value. Under the condition of satisfying . In order to Figure 8 and Figure 9 the thermocouple structures shown can all achieve the same optimal cooling thermal power, the following formula needs to be satisfied: , because , so , then it can be understood that Figure 9 the volume of the thermoelectric element in the second thermocouple structure shown in will be less than Figure 3 the volume of the thermoelectric element in the traditional thermocouple structure shown in , that is . It can be seen that by adopting Figure 9 the second thermocouple structure, a smaller-sized thermoelectric element can achieve the heat dissipation effect achieved by a larger-sized thermoelectric element in the traditional thermocouple structure. Therefore, by adopting Figure 9 the second thermocouple structure, more thermoelectric elements can be arranged in the same space, thereby increasing the heat dissipation density.

[0084] In the second thermocouple structure, the dimension of the conductive heat dissipation member along the current direction is the thickness of the conductive heat dissipation member, and the thickness of the conductive heat dissipation member is less than the preset threshold. It can be understood that in the conventional thermocouple structure, the P-type thermoelectric element and the N-type thermoelectric element have the same size, and the thickness of the conductive heat dissipation member is generally set to be relatively small, that is, less than the side length of the cross-section of the thermoelectric element perpendicular to the current direction. This can further ensure that the thermocouple structure provided by the present application can achieve the heat dissipation effect achieved by a larger-sized thermoelectric element in the traditional thermocouple structure with a smaller-sized thermoelectric element. That is, the above preset threshold can be set to the minimum value of the above cross-section side length. For example Figure 9 as shown in , the above preset threshold can be set to be less than the

[0085] value.

[0086] When an element (e.g., a first element) is referred to as being “(operatively or communicatively) coupled” or “(operatively or communicatively) coupled to” or “connected to” another element (e.g., a second element), it should be understood that the one element is directly connected to the other element or the one element is indirectly connected to the other element via yet another element (e.g., a third element). Conversely, it will be understood that when an element (e.g., a first element) is referred to as being “directly connected” or “directly coupled” to another element (a second element), no element (e.g., a third element) is inserted therebetween.

[0087] It should be noted that, in this document, the terms “comprising,” “including,” or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but also other elements not expressly listed or elements that are inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising a...” does not exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or may have different meanings, and their specific meanings need to be determined based on their explanations in the specific embodiments or further in combination with the context of the specific embodiments.

[0088] The above description is only an alternative embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, technical solutions formed by mutually replacing the above features with (but not limited to) technical features having similar functions disclosed in the present application.

[0089] Depending on the context, the words “if,” “when” as used herein can be interpreted as “when” or “upon” or “in response to determining” or “in response to detecting.” Similarly, depending on the context, the phrase “if determined” or “if detected (stated condition or event)” can be interpreted as “when determined” or “in response to determining” or “when detected (stated condition or event)” or “in response to detecting (stated condition or event).”

[0090] The above description is only an optional embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the technical solution formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present application.

[0091] The above is only an optional embodiment of the present application and is not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A semiconductor laser, characterized in that, It includes a semiconductor stack structure and a thermoelectric cooling device; The semiconductor stack structure includes a first region and a second region surrounding the first region. The first region constitutes an array of double heterojunction structures sharing a first-type doped semiconductor layer. The dopant in the second region is different from that in the first region, and the doping concentration in the second region is higher than that in the first region; The thermoelectric cooling device is disposed in the second region and is configured to dissipate heat from the double heterojunction structure array; The thermoelectric cooling device includes P-type thermoelectric elements and N-type thermoelectric elements arranged alternately along the current direction of the thermoelectric cooling device. Adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically connected by a conductive heat dissipation member to form a thermocouple structure; The thermocouple structure includes at least one of the following: Adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically connected by a conductive heat dissipation member covering the same-side surfaces of both, forming a first thermocouple structure. Among them, two adjacent conductive heat dissipation members are disposed on opposite surfaces of the same thermoelectric element; Adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically connected by a conductive heat dissipation member sandwiched between them, forming a second thermocouple structure.

2. The semiconductor laser according to claim 1, wherein At least one channel surrounding the first region is provided in the second region, and the thermoelectric cooling device is disposed in the channel, and / or the thermoelectric cooling device is disposed outside the channel.

3. The semiconductor laser according to claim 1, wherein The thermocouple structures are arranged end to end along the edge contour of the double heterojunction structure array; and / or the thermocouple structures are arranged end to end to cover the second region in a preset path.

4. The semiconductor laser according to claim 1, wherein In the second thermocouple structure, at least one of the conductive heat dissipation members extends toward the semiconductor stack structure to form a first heat dissipation disk; at least one of the conductive heat dissipation members extends in a direction away from the semiconductor stack structure to form a second heat dissipation disk; adjacent two of the conductive heat dissipation members extend in different directions.

5. The semiconductor laser according to claim 1, wherein In the second thermocouple structure, the P-type thermoelectric element and / or the N-type thermoelectric element are deposited on the first-type doped semiconductor layer by a vapor deposition process.

6. The semiconductor laser according to claim 1, wherein The thermoelectric cooling device further includes at least one protection plate covering the second thermocouple structure and / or the first thermocouple structure, and the protection plate is bonded to the second region by a gold-gold bonding method.

7. The semiconductor laser according to claim 2, wherein The double heterojunction structure array is grown on a substrate layer. Each double heterojunction structure includes the first-type doped semiconductor layer, an active layer, and a second-type doped semiconductor layer stacked, and a second chip electrode is provided on the second-type doped semiconductor layer; A first chip electrode is disposed on a side of the substrate layer facing away from the double heterojunction structure array, and the first chip electrode is communicated with the first-type doped semiconductor layer through the substrate layer.

8. The semiconductor laser according to claim 7, wherein the semiconductor stack structure includes a first semiconductor layer, a second semiconductor layer, and a third semiconductor layer stacked in sequence; the first semiconductor layer is doped with a pentavalent element substance in the first region to form an N-type doped semiconductor layer; the third semiconductor layer is doped with a trivalent element substance in the first region to form a P-type doped semiconductor layer; the second semiconductor layer adopts a multi-quantum well structure in the first region to form an active layer; the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer are doped with H+ substance in the second region.

9. The semiconductor laser according to claim 8, wherein the channel located in the second region sequentially penetrates through the third semiconductor layer and the second semiconductor layer, and exposes a partial surface of the first semiconductor layer.

10. The semiconductor laser according to claim 8, wherein the thermoelectric cooling device is disposed on a side of the third semiconductor layer in the second region facing away from the substrate layer; and / or the thermoelectric cooling device is located on a light-emitting direction side of the double heterojunction structure array.

11. The semiconductor laser according to any one of claims 1 to 10, wherein the double heterojunction structure array includes at least one of the following: at least two double heterojunction structures arranged in an axisymmetric or centrosymmetric manner; seven double heterojunction structures arranged in an axisymmetric or centrosymmetric manner.

12. The semiconductor laser according to claim 11, wherein, The edge contour of the double heterojunction structure array includes at least one of the following: the edge contour of the double heterojunction structure array is an axisymmetric polygon; the edge contour of the double heterojunction structure array is a centrosymmetric polygon.

13. A lidar, characterized in that, It includes a transmitting component and a receiving component; the transmitting component uses the semiconductor laser according to any one of claims 1-12.

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