A vertical cavity surface emitting laser

Abstract

The application discloses a vertical cavity surface emitting laser, and relates to the technical field of semiconductor lasers, wherein a tunneling junction connecting two adjacent active layers comprises at least one tunneling unit, the tunneling unit comprises a second-type doped layer and a first-type doped layer which are stacked in sequence, the second-type doped layer comprises a second-type semiconductor layer, and the first-type doped layer comprises a first-type semiconductor layer; a second-type strain layer is arranged on the side of the second-type semiconductor layer close to the first-type doped layer, and / or a first-type strain layer is arranged on the side of the first-type semiconductor layer close to the second-type doped layer, so as to change the internal strain of the second-type semiconductor layer and / or the first-type semiconductor layer, and introduce an interface strain between the second-type doped layer and the first-type doped layer, thereby facilitating the improvement of the tunneling unit and the tunneling efficiency of the tunneling junction, and the performance of the vertical cavity surface emitting laser.

Description

Technical Field

[0001] This application relates to the field of semiconductor laser technology, and more particularly to a vertical cavity surface-emitting laser. Background Technology

[0002] With the development of the Internet of Things (IoT), Artificial Intelligence (AI), and 5G technologies, 3D imaging and sensing technologies have experienced rapid growth, driving the development of multiple fields such as smartphones, smart cars, and augmented reality / virtual reality (AR / VR), and accelerating the arrival of the era of the Internet of Everything. Vertical-Cavity Surface-Emitting Lasers (VCSELs), as core components of 3D imaging and sensing systems, are at the pinnacle of the intelligent interconnected industry.

[0003] High-power vertical-cavity surface-emitting lasers (VCSELs) are currently a popular type of laser on the market. For CCSELs, high power, reaching up to the kW level, can be achieved through large apertures, back-emitting, array arrangements, or multi-junction structures. Among these, the multi-junction structure is an effective means of epitaxially achieving high power in CCSELs, particularly in automotive radar applications. Multi-junction CCSELs specifically utilize tunneling junctions to stack multiple active layers in the vertical direction, connecting these active layers in series. This significantly improves the laser's power density and photoelectric conversion efficiency. Therefore, tunneling junction technology is one of the most critical technologies for multi-junction CCSELs.

[0004] In existing multi-junction vertical-cavity surface-emitting lasers, the tunneling junction is usually constructed using materials such as GaAs, AlGaAs, GaInP, and AlGaInP to form a double-layer structure. As the power requirements of vertical-cavity surface-emitting lasers become increasingly higher, the number of junctions required also increases. In order to meet the requirements of low voltage and high performance, higher requirements are placed on the low junction resistance and high tunneling efficiency of the tunneling junction in multi-junction vertical-cavity surface-emitting lasers. However, conventional epitaxial growth processes make it difficult to obtain tunneling junctions with higher doping concentrations to improve tunneling efficiency. Utility Model Content

[0005] To address the aforementioned technical problems, this application provides a vertical cavity surface-emitting laser (VCSEL) to improve the tunneling efficiency of the tunnel junction in a multi-junction VCSEL, thereby improving the performance of the multi-junction VCSEL.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A vertical cavity surface-emitting laser includes a substrate and a first type reflective layer, a resonant cavity layer, and a second type reflective layer stacked on one side of the substrate;

[0008] The resonant cavity layer includes at least two active layers, and a tunneling junction is disposed between two adjacent active layers. The tunneling junction includes at least one tunneling unit, and the tunneling unit includes a second type doped layer and a first type doped layer stacked in sequence. The second type doped layer includes a second type semiconductor layer, and the first type doped layer includes a first type semiconductor layer.

[0009] The second type doped layer further includes a second type strain layer located on the side of the second type semiconductor layer near the first type doped layer, and / or the first type doped layer further includes a first type strain layer located on the side of the first type semiconductor layer near the second type doped layer.

[0010] Optionally, the thickness of the second type of strain layer is no more than 1 / 3 of the thickness of the second type of semiconductor layer;

[0011] The thickness of the first type of strain layer is no greater than 1 / 3 of the thickness of the first type of semiconductor layer.

[0012] Optionally, the second type semiconductor layer is an arsenide layer or an indium arsenide layer, and the second type strain layer is an indium arsenide layer; or, the second type semiconductor layer is a phosphide layer, and the second type strain layer is an indium phosphide layer;

[0013] The first type of semiconductor layer is an arsenide layer or an indium arsenide layer, and the first type of strain layer is an indium arsenide layer; or, the first type of semiconductor layer is a phosphide layer or an indium phosphide layer, and the first type of strain layer is an indium phosphide layer.

[0014] Optionally, the second type of semiconductor layer is a GaAs layer, GaInAs layer, AlGaAs layer, AlGaInAs layer, GaAsP layer, GaInAsP layer, AlGaAsP layer, AlGaInAsP layer, AlGaInP layer, or GaInP layer.

[0015] The first type of semiconductor layer is a GaAs layer, GaInAs layer, AlGaAs layer, AlGaInAs layer, GaAsP layer, GaInAsP layer, AlGaAsP layer, AlGaInAsP layer, AlGaInP layer, AlGaInP layer, or GaInP layer.

[0016] Optionally, the second type of doped layer includes a first portion close to the first type of doped layer and a second portion away from the first type of doped layer, wherein the doping concentration of the first portion is greater than that of the second portion, and the thickness of the first portion is not greater than 1.5 nm.

[0017] And / or, the first type of doped layer includes a third portion close to the second type of doped layer and a fourth portion far from the second type of doped layer, wherein the doping concentration of the third portion is greater than that of the fourth portion, and the thickness of the third portion is not greater than 1.5 nm.

[0018] Optionally, the second type of semiconductor layer includes alternating layers of a first sub-semiconductor layer and a second sub-semiconductor layer, wherein the doping concentration of the first sub-semiconductor layer is greater than the doping concentration of the second sub-semiconductor layer, and the doping concentration of the first sub-semiconductor layer is not less than 5E19cm⁻¹. -3 The doping concentration of the second sub-semiconductor layer is not less than 1E19cm. -3 ;

[0019] And / or, the first type of semiconductor layer includes alternately stacked third and fourth sub-semiconductor layers, wherein the doping concentration of the third sub-semiconductor layer is greater than that of the fourth sub-semiconductor layer, and the doping concentration of the third sub-semiconductor layer is not less than 5E19cm⁻¹. -3 The doping concentration of the fourth sub-semiconductor layer is not less than 1E19cm. -3 .

[0020] Optionally, the tunneling junction includes at least two stacked tunneling units.

[0021] Optionally, the thickness of the tunnel junction is no greater than 200 nm, and the ratio of the thickness of the second type doped layer to the thickness of the first type doped layer is no less than 1 / 4 and no greater than 4.

[0022] Compared with existing technologies, the above technical solution has the following advantages:

[0023] The vertical-cavity surface-emitting laser provided in this application includes a substrate and a first-type reflective layer, a resonant cavity layer, and a second-type reflective layer stacked on one side of the substrate. The resonant cavity layer includes at least two active layers, and a tunneling junction is disposed between adjacent active layers, i.e., adjacent active layers are connected in series through the tunneling junction to improve the power density and photoelectric conversion efficiency of the laser. Meanwhile, the tunneling junction includes at least one tunneling unit, which includes a second-type doped layer and a first-type doped layer stacked sequentially. The second-type doped layer, in addition to including a second-type semiconductor layer, may also include a second-type strain layer located on the side of the second-type semiconductor layer closer to the first-type doped layer, to introduce strain through the second-type strain layer. This can change the internal strain of the second type semiconductor layer and introduce strain at the interface between the second type doped layer and the first type doped layer, which is beneficial to improving the tunneling efficiency of the tunneling unit, and thus improving the tunneling efficiency of the tunnel junction; and / or, in addition to the first type semiconductor layer, the first type doped layer may also include a first type strain layer located on the side of the first type semiconductor layer closer to the second type doped layer, so that strain can be introduced through the first type strain layer, which can change the internal strain of the first type semiconductor layer and introduce strain at the interface between the first type doped layer and the second type doped layer, which is beneficial to improving the tunneling efficiency of the tunneling unit, and thus improving the tunneling efficiency of the tunnel junction; thereby improving the performance of the multi-junction vertical cavity surface-emitting laser. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a cross-sectional structural diagram of a vertical cavity surface-emitting laser provided in an embodiment of this application;

[0026] Figure 2 This is a cross-sectional structural diagram of another vertical cavity surface-emitting laser provided in an embodiment of this application;

[0027] Figure 3 A cross-sectional structural schematic diagram of another vertical cavity surface-emitting laser provided in the embodiments of this application;

[0028] Figure 4 A cross-sectional structural schematic diagram of another vertical cavity surface-emitting laser provided in the embodiments of this application;

[0029] Figure 5 A cross-sectional structural schematic diagram of another vertical cavity surface-emitting laser provided in the embodiments of this application;

[0030] Figure 6 This is a cross-sectional structural diagram of another vertical cavity surface-emitting laser provided in the embodiments of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 100 Substrate; 101 Buffer layer; 200 Type I reflective layer; 210 First refractive index layer; 220 Second refractive index layer; 300 Resonant cavity layer; 310 Light-emitting unit; 311 Active layer; 3111 Barrier layer; 3112 Potential well layer; 312 Type I waveguide layer; 313 Type II waveguide layer; 314 Type II oxide layer; 3141 Oxidized portion; 3142 Unoxidized portion; 320 Tunnel junction; 10 Tunneling unit; 11 Type I doped layer; 111 Type I semiconductor layer; 112 First... Type 1 strain layer; Type 2 doped layer; Type 2 semiconductor layer; Type 2 strain layer; Type 2 strain layer; Type 1 first part; Type 2 second part; Type 3 third part; Type 4 fourth part; Type 121A first sub-semiconductor layer; Type 2 sub-semiconductor layer; Type 31A third sub-semiconductor layer; Type 41B fourth sub-semiconductor layer; Type 2 conductive layer; Type 340 first conductive layer; Type 2 reflective layer; Type 3 refractive index layer; Type 420 fourth refractive index layer; Type 2 ohmic contact layer. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate; this is merely a way of distinguishing objects with the same properties in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0035] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the accompanying drawings illustrating the device structure may be partially enlarged, not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0036] As described in the background section, in existing multi-junction vertical-cavity surface-emitting lasers, the tunneling junction is usually constructed using materials such as GaAs, AlGaAs, GaInP, and AlGaInP to form a double-layer structure. However, as the power requirements of vertical-cavity surface-emitting lasers become increasingly higher, the number of junctions required also increases. In order to meet the demand for low voltage and high performance, higher requirements are placed on the low junction resistance and high tunneling efficiency of the tunneling junction in multi-junction vertical-cavity surface-emitting lasers. However, conventional epitaxial growth processes make it difficult to obtain tunneling junctions with higher doping concentrations to improve tunneling efficiency.

[0037] In view of this, embodiments of this application provide a vertical-cavity surface-emitting laser. Figures 1-3 The following are schematic cross-sectional views of three vertical cavity surface-emitting lasers provided in the embodiments of this application: Figures 1-3 As shown, the vertical cavity surface-emitting laser includes a substrate 100 and a first type reflective layer 200, a resonant cavity layer 300, and a second type reflective layer 400 stacked on one side of the substrate 100.

[0038] In this embodiment, the substrate 100 may be a GaAs substrate. A buffer layer 101 may be present between the substrate 100 and the first type reflective layer 200.

[0039] The first type of reflective layer 200 can be a first type of doped distributed Bragg reflector (DBR) layer, specifically including an alternately stacked first refractive index layer 210 and second refractive index layer 220, one of the first refractive index layer 210 and the other of the second refractive index layer 220 being a high refractive index layer and the other being a low refractive index layer, and the optical thickness of both the first refractive index layer 210 and the second refractive index layer 220 being 1 / 4 optical wavelength.

[0040] Similarly, the second type reflective layer 400 can be a second type doped DBR layer, specifically including alternating layers of a third refractive index layer 410 and a fourth refractive index layer 420. One of the third refractive index layer 410 and the fourth refractive index layer 420 is a high refractive index layer and the other is a low refractive index layer. The optical thickness of both the third refractive index layer 410 and the fourth refractive index layer 420 is 1 / 4 optical wavelength.

[0041] The first type of reflective layer 200 and the second type of reflective layer 400 constitute a resonant cavity, which filters and reflects light of a specific wavelength to form laser oscillation.

[0042] The resonant cavity layer 300 between the first type reflective layer 200 and the second type reflective layer 400 includes at least two active layers 311, and a tunnel junction 320 is disposed between two adjacent active layers 311. Alternatively, the resonant cavity layer 300 includes at least two stacked light-emitting units 310, each light-emitting unit 310 including an active layer 311, and a tunnel junction 320 is disposed between two adjacent light-emitting units 310. Thus, two adjacent active layers 311 (or two adjacent light-emitting units 310) are connected in series through the tunnel junction 320, thereby connecting each active layer 311 (or each light-emitting unit 310) in series to improve the power density and photoelectric conversion efficiency of the laser.

[0043] In fact, in addition to the active layer 311, the light-emitting unit 310 also includes a first type waveguide layer 312 located on the side of the active layer 311 close to the substrate 100, a second type waveguide layer 313 located on the side of the active layer 311 away from the substrate 100, and a second type oxide layer 314 located on the side of the second type waveguide layer 313 away from the active layer 311. The active layer 311 includes alternating layers of barrier layer 3111 and potential well layer 3112. Under the action of injected current, electrons and holes recombine in the active layer 311, generating laser light through stimulated emission. The first type waveguide layer 312 and the second type waveguide layer 313 work together to confine the current and the optical field, precisely controlling the current flow to the active layer and effectively confining photons near the active layer, reducing optical loss and forming an optical waveguide. The second type oxide layer 314 includes an oxidized portion 3141 and an unoxidized portion 3142. The oxidized portion 3141 has high insulation and low refractive index, while the unoxidized portion 3142 forms an oxide confinement window (also known as an oxide aperture), forcing the current to concentrate in the central channel and forming an optical waveguide to confine the optical field.

[0044] In this embodiment, the tunnel junction 320 includes at least one tunneling unit 10, and the tunneling unit 10 includes a second type doped layer 12 and a first type doped layer 11 stacked sequentially.

[0045] In addition to the second type semiconductor layer 121, the second type doped layer 12 may also include a second type strain layer 122 located on the side of the second type semiconductor layer 121 close to the first type doped layer 11. By introducing strain through the second type strain layer 122, the internal strain of the second type semiconductor layer 121 can be changed, and strain can be introduced at the interface between the second type doped layer 12 and the first type doped layer 11, which is beneficial to improving the tunneling efficiency of the tunneling unit 10, thereby improving the tunneling efficiency of the tunnel junction 320.

[0046] Optionally, the thickness of the second type strain layer 122 may not be greater than 1 / 3 of the thickness of the second type semiconductor layer 121, that is, the thickness of the second type strain layer 122 is relatively thin, so as to be able to introduce strain as a strain layer.

[0047] Optionally, the second type strain layer 122 is a material layer containing In elements, and the In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121. Specifically, if the second type semiconductor layer 121 is a material layer that does not contain In elements, then the second type strain layer 122 is a material layer containing In elements; if the second type semiconductor layer 121 is a material layer that contains In elements, then the second type strain layer 122 is a material layer that contains In elements, and the In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121. In short, the In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121 (which can be 0). With this configuration, the second type strain layer 122 can introduce strain through In elements, and the magnitude of the introduced strain can be adjusted by adjusting the In composition.

[0048] Similarly, in addition to the first type semiconductor layer 111, the first type doped layer 11 may also include a first type strain layer 112 located on the side of the first type semiconductor layer 111 close to the second type doped layer 12, so that strain can be introduced through the first type strain layer 112, which can change the internal strain of the first type strain layer 112 and introduce strain at the interface between the first type doped layer 11 and the second type doped layer 12, which is beneficial to improve the tunneling efficiency of the tunneling unit 10, and thus improve the tunneling efficiency of the tunnel junction 320.

[0049] Optionally, the thickness of the first type of strain layer 112 may not be greater than 1 / 3 of the thickness of the first type of semiconductor layer 111, that is, the thickness of the first type of strain layer 112 is relatively thin, so as to be able to introduce strain as a strain layer.

[0050] Optionally, the first type strain layer 112 is a material layer containing In elements, and the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111. Specifically, if the first type semiconductor layer 111 is a material layer that does not contain In elements, then the first type strain layer 112 is a material layer containing In elements; if the first type semiconductor layer 111 is a material layer that contains In elements, then the first type strain layer 112 is a material layer that contains In elements, and the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111. In short, the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111 (which can be 0). With this configuration, the first type strain layer 112 can introduce strain through In elements, and the magnitude of the introduced strain can be adjusted by adjusting the In composition.

[0051] Therefore, the vertical-cavity surface-emitting laser provided in this application improves the tunneling efficiency of the tunneling unit 10 by adding a second type strain layer 122 to the side of the second type semiconductor layer 121 near the first type semiconductor layer 111, and / or adding a first type strain layer 112 to the side of the first type semiconductor layer 111 near the second type semiconductor layer 121 in the tunneling unit 10 of the tunnel junction 320. This introduces strain, changes the internal strain of the second type semiconductor layer 121 and / or the first type semiconductor layer 111, and introduces interface strain between the second type semiconductor layer 121 and the first type semiconductor layer 111. This improves the tunneling efficiency of the tunneling unit 10, thereby improving the tunneling efficiency of the tunnel junction 320 and thus improving the performance of the multi-junction vertical-cavity surface-emitting laser.

[0052] It is understood that, in the embodiments of this application, optional features, such as... Figure 1 As shown, the second type doped layer 12 can be provided only, including a second type semiconductor layer 121 and a second type strain layer 122 located on the side of the second type semiconductor layer 121 near the first type doped layer 11, while the first type doped layer 11 only includes a first type semiconductor layer 111; another option is, as... Figure 2 As shown, the first type doped layer 11 can be provided only, including a first type semiconductor layer 111 and a first type strain layer 112 located on the side of the first type semiconductor layer 111 near the second type doped layer 12, while the second type doped layer 12 only includes a second type semiconductor layer 121; alternatively, such as Figure 3 As shown, the second type doped layer 12 can be provided, including a second type semiconductor layer 121 and a second type strain layer 122 located on the side of the second type semiconductor layer 121 near the first type doped layer 11, and the first type doped layer 11 can also be provided, including a first type semiconductor layer 111 and a first type strain layer 112 located on the side of the first type semiconductor layer 111 near the second type doped layer 12.

[0053] It is also understood that by providing both the second type doped layer 12, including the second type semiconductor layer 121 and the second type strain layer 122 located on the side of the second type semiconductor layer 121 near the first type doped layer 11, and also providing the first type doped layer 11, including the first type semiconductor layer 111 and the first type strain layer 112 located on the side of the first type semiconductor layer 111 near the second doped layer 12, compared to providing only the second type doped layer 12, including the second type semiconductor layer 121 and the second type strain layer 122 located on the side of the second type semiconductor layer 121 near the first doped layer 11, or only the first type doped layer 11, including the first type semiconductor layer 111 and the first type strain layer 112 located on the side of the first type semiconductor layer 111 near the second doped layer 12, it is possible to change the internal strain of the second type semiconductor layer 121 and the internal strain of the first type semiconductor layer 111, and introduce strain at the interface between the first type doped layer 11 and the second type doped layer 12, which can further improve the tunneling efficiency of the tunneling unit 10, and thus improve the tunneling efficiency of the tunnel junction 320.

[0054] As previously known, when the second type doped layer 12 includes a second type semiconductor layer 121 and a second type strain layer 122 located on the side of the second type semiconductor layer 121 close to the first type doped layer 11, the second type strain layer 122 can be a material layer containing In elements. The In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121 (which can be 0). Thus, the second type semiconductor layer 121 and the second type strain layer 122 can be the same material layer, but the In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121 (which can be 0), so as to increase the In composition in the second type strain layer 122 to introduce strain, thereby improving the tunneling efficiency.

[0055] Optionally, the second type semiconductor layer 121 can be an arsenide layer. If the second type semiconductor layer 121 is an arsenide layer without In, then In is added to the second type strain layer 122, making the second type strain layer 122 an arsenide layer containing In, i.e., an indium arsenide layer. If the second type semiconductor layer 121 is an arsenide layer containing In, i.e., an indium arsenide layer, then the second type strain layer 122 is an arsenide layer containing In with a larger In content, i.e., an indium arsenide layer with a larger In content. However, when the second type strain layer 122 is an indium arsenide layer, the In content of the second type strain layer 122 should not exceed 10%. This is because the larger the In content, the larger the strain introduced by the second type strain layer 122, and introducing too much strain can lead to mismatch problems.

[0056] Alternatively, the second type semiconductor layer 121 can be a phosphide layer. If the second type semiconductor layer 121 is a phosphide layer without In, then In is added to the second type strain layer 122, making the second type strain layer 122 an In-containing phosphide layer, i.e., an indium phosphide layer. If the second type semiconductor layer 121 is an In-containing phosphide layer, i.e., an indium phosphide layer, then the second type strain layer 122 is an In-containing phosphide layer with a larger In content, i.e., an indium phosphide layer with a larger In content. However, when the second type strain layer 122 is an indium phosphide layer, the In content of the second type strain layer 122 should not exceed 60%. This is because a larger In content results in a larger strain introduced into the second type strain layer 122, and excessive strain can lead to mismatch problems.

[0057] Specifically, the material of the second type semiconductor layer 121 includes at least one of GaAs, GaInAs, AlGaAs, AlGaInAs, GaAsP, GaInAsP, AlGaAsP, AlGaInAsP, AlGaInP, AlGaInP, and GaInP. For example, the second type semiconductor layer 121 can be a GaAs layer, GaInAs layer, AlGaAs layer, AlGaInAs layer, GaAsP layer, GaInAsP layer, AlGaAsP layer, AlGaInAsP layer, AlGaInP layer, or GaInP layer; the second type strain layer 122 can increase or increase the In content based on the material of the second type semiconductor layer 121. Among them, GaAs, GaInAs, AlGaAs, AlGaInAs, GaAsP, GaInAsP, AlGaAsP, and AlGaInAsP materials can be considered as arsenide materials or arsenide materials with a small amount of phosphorus doping. When these materials are used in the second type strain layer 122, the In content should not exceed 10%. AlGaInP and GaInP materials can be considered as phosphide materials. When these materials are used in the second type strain layer 122, the In content should not exceed 60%.

[0058] As previously known, when the first type doped layer 11 includes a first type semiconductor layer 111 and a first type strain layer 112 located on the side of the first type semiconductor layer 111 near the second type doped layer 12, the first type strain layer 112 can be a material layer containing In elements, and the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111 (which can be 0). Thus, optionally, the first type semiconductor layer 111 and the first type strain layer 112 can be the same material layer, but the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111 (which can be 0), so as to increase the In composition in the first type strain layer 112 to introduce strain, thereby improving the tunneling efficiency.

[0059] Optionally, the first type semiconductor layer 111 can be an arsenide layer. If the first type semiconductor layer 111 is an arsenide layer without In, then In is added to the first type strain layer 112, making the first type strain layer 112 an arsenide layer containing In, i.e., an indium arsenide layer. If the first type semiconductor layer 111 is an arsenide layer containing In, i.e., an indium arsenide layer, then the first type strain layer 112 is an arsenide layer containing In with a larger In content, i.e., an indium arsenide layer with a larger In content. However, when the first type strain layer 112 is an indium arsenide layer, the In content of the first type strain layer 112 should not exceed 10%. This is because the larger the In content, the larger the strain introduced by the first type strain layer 112, and introducing too much strain can lead to mismatch problems.

[0060] Alternatively, the first type semiconductor layer 111 can be a phosphide layer. If the first type semiconductor layer 111 is a phosphide layer without In, then In is added to the first type strain layer 112, making the first type strain layer 112 a phosphide layer containing In, i.e., an indium phosphide layer. If the first type semiconductor layer 111 is a phosphide layer containing In, i.e., an indium phosphide layer, then the first type strain layer 112 is a phosphide layer containing In with a larger In content, i.e., an indium phosphide layer with a larger In content. However, when the first type strain layer 112 is an indium phosphide layer, the In content of the first type strain layer 112 should not exceed 60%. This is because the larger the In content, the larger the strain introduced by the first type strain layer 112, and introducing too much strain can lead to mismatch problems.

[0061] Specifically, the material of the first type semiconductor layer 111 includes at least one of GaAs, GaInAs, AlGaAs, AlGaInAs, GaAsP, GaInAsP, AlGaAsP, AlGaInAsP, AlGaInP, AlGaInP, and GaInP. For example, the first type semiconductor layer 111 can be a GaAs layer, GaInAs layer, AlGaAs layer, AlGaInAs layer, GaAsP layer, GaInAsP layer, AlGaAsP layer, AlGaInAsP layer, AlGaInP layer, or GaInP layer; the first type strain layer 112 can increase or increase the In content based on the material of the first type semiconductor layer 111. Among them, GaAs, GaInAs, AlGaAs, AlGaInAs, GaAsP, GaInAsP, AlGaAsP, and AlGaInAsP materials can be considered as arsenide materials or arsenide materials with a small amount of phosphorus doping. When these materials are used in the first type strain layer 112, the In content should not exceed 10%. AlGaInP and GaInP materials can be considered as phosphide materials. When these materials are used in the first type strain layer 112, the In content should not exceed 60%.

[0062] Furthermore, the inventors discovered that, based on... Figure 4 As shown, Figure 4 This paper illustrates a cross-sectional view of another vertical-cavity surface-emitting laser provided in an embodiment of this application. It can be seen that in the tunneling unit 10, when forming the second type-doped layer 12, the second type-doped layer 12 can be epitaxially grown first; then, growth is paused, the reaction chamber temperature is lowered, and second type delta doping is performed on the surface of the second type-doped layer 12 away from the substrate 100 (i.e., the surface of the second type-doped layer 12 facing the first type-doped layer 11). Specifically, second type delta doping is performed on the portion of the second type-doped layer 12 close to the first type-doped layer 11. It is understood that delta doping is a semiconductor doping technique that concentrates impurity atoms within a very narrow range (typically a thin layer of a few atomic layers). In this application, by performing second type delta doping on the surface of the second type-doped layer 12 away from the substrate 100, the impurity atoms diffuse and can be concentrated within a few atomic layers of the surface of the second type-doped layer 12 close to the first type-doped layer 11, such as a range greater than 1E21 cm. -3The high-concentration doping is structurally manifested as follows: the second-type doped layer 12 includes a first portion B1 close to the first-type doped layer 11 and a second portion B2 far from the first-type doped layer 11. The doping concentration of the first portion B1 is greater than that of the second portion B2, and the thickness of the first portion B1 is no greater than 1.5 nm. With this configuration, since the doping concentration is greater than 1E21 cm in a few atomic layers near the surface of the second-type doped layer 12 close to the first-type doped layer 11, the doping concentration is significantly higher. -3 The high concentration of doping allows for the formation of a localized high electric field within a few atomic layers of the second type doped layer 12 near the surface of the first type doped layer 11, thereby enhancing tunneling efficiency.

[0063] Similarly, refer to Figure 4 As shown, the portion of the first type doped layer 11 near the second type doped layer 12 can also be subjected to first type delta doping. Specifically, in the tunneling unit 10, when forming the first type doped layer 11, a portion of the first type doped layer can be epitaxially grown first; then, growth is paused, the reaction chamber temperature is lowered, and the surface of the grown portion of the first type doped layer away from the substrate 100 is subjected to first type delta doping; next, the remaining first type doped layer is epitaxially grown. It can be understood that by performing first type delta doping on the surface of the first type doped layer away from the substrate 100, after impurity atom diffusion and epitaxial growth of the remaining first type doped layer, impurity atoms can be concentrated in a few atomic layers, such as greater than 1E21 cm, within the surface layer of the first type doped layer 11 near the second type doped layer 12. -3 The high-concentration doping is structurally manifested as follows: the first-type doped layer 11 includes a third part B3 close to the second-type doped layer 12 and a fourth part B4 far from the second-type doped layer 12. The doping concentration of the third part B3 is greater than that of the fourth part B4, and the thickness of the third part B3 is no greater than 1.5 nm. With this configuration, due to the concentration of more than 1E21 cm in a few atomic layers near the surface of the first-type doped layer 11 close to the second-type doped layer 12, the doping concentration is significantly higher. -3 The high concentration of doping allows for the formation of a localized high electric field within a few atomic layers of the surface of the first type doped layer 11 near the surface of the second type doped layer 12, thereby enhancing tunneling efficiency.

[0064] Of course, for reference Figure 4As shown, it is also possible to perform type II delta doping on the portion of the type II doped layer 12 near the type I doped layer 11, and type I delta doping on the portion of the type I doped layer 11 near the type II doped layer 12. Structurally, the type II doped layer 12 includes a first portion B1 near the type I doped layer 11 and a second portion B2 away from the type I doped layer 11. The doping concentration of the first portion B1 is greater than that of the second portion B2, and the thickness of the first portion B1 is no greater than 1.5 nm. Furthermore, the type I doped layer 11 includes a third portion B3 near the type II doped layer 12 and a fourth portion B4 away from the type II doped layer 12. The doping concentration of the third portion B3 is greater than that of the fourth portion B4, and the thickness of the third portion B3 is no greater than 1.5 nm. With this configuration, since the concentration of the second type doped layer 12 within a few atomic layers near the surface of the type I doped layer 11 is greater than 1E21 cm... -3 High concentration doping, and concentrated in a few atomic layers near the surface of the first type doped layer 11 close to the second type doped layer 12, such as greater than 1E21cm. -3 The high concentration of doping allows for the formation of a localized high electric field within a few atomic layers of the second type doped layer 12 near the surface of the first type doped layer 11, and within a few atomic layers of the first type doped layer 11 near the surface of the second type doped layer 12, thereby further enhancing the tunneling efficiency.

[0065] It should be noted that, in the second type doped layer 12, the thickness of the first portion B1 can be less than, equal to, or greater than the thickness of the second type strained layer 122; similarly, in the first type doped layer 11, the thickness of the third portion B3 can be less than, equal to, or greater than the thickness of the first type strained layer 112. This application does not impose any limitations on this. Figure 4 The first type strain layer 112 and the second type strain layer 122 are not shown.

[0066] Furthermore, the inventors discovered that, based on... Figure 5 As shown, Figure 5 This paper presents a cross-sectional structural schematic diagram of another vertical-cavity surface-emitting laser provided in an embodiment of this application. It can be seen that during the growth of the second-type semiconductor layer 121 in the second-type doped layer 12, a high-low pulse method can be used, such that the second-type semiconductor layer 121 includes alternately stacked first sub-semiconductor layers 121A and 121B. The doping concentration of the first sub-semiconductor layer 121A is greater than that of the second sub-semiconductor layer 121B, and the doping concentration of the first sub-semiconductor layer 121A is not less than 5E19cm⁻¹. -3 The doping concentration of the second sub-semiconductor layer 121B is not less than 1E19 cm⁻¹. -3With this configuration, the doping concentrations of the second type semiconductor layer 121 are arranged in alternating high and low concentrations. First, this can increase the overall doping concentration of the second type semiconductor layer 121. Second, it can also prevent excessively high doping concentrations of the second type semiconductor layer 121 from causing epitaxial crystal defects or dopant precipitation, thus balancing the crystal quality of the second type semiconductor layer 121 and preventing or reducing the trapping of charge carriers in the second type semiconductor layer 121. This improves the tunneling efficiency of the tunneling unit 10, and further improves the tunneling efficiency of the tunnel junction 320.

[0067] Similarly, refer to Figure 5 As shown, during the growth of the first type semiconductor layer 111 in the first type doped layer 11, a high-low phase pulse method can also be used, so that the first type semiconductor layer 111 includes alternating layers of a third sub-semiconductor layer 111A and a fourth sub-semiconductor layer 111B, wherein the doping concentration of the third sub-semiconductor layer 111A is greater than the doping concentration of the fourth sub-semiconductor layer 111B, and the doping concentration of the third sub-semiconductor layer 111A is not less than 5E19cm⁻¹. -3 The doping concentration of the fourth sub-semiconductor layer 111B is not less than 1E19cm. -3 With this configuration, the doping concentrations of the first type semiconductor layer 111 are arranged in alternating high and low concentrations. First, this can increase the overall doping concentration of the first type semiconductor layer 111. Second, it can also prevent excessively high doping concentrations of the first type semiconductor layer 111 from causing epitaxial crystal defects or doping impurities to precipitate, thus balancing the crystal quality of the first type semiconductor layer 111 and preventing or reducing the trapping of carriers in the first type semiconductor layer 111. This improves the tunneling efficiency of the tunneling unit 10, and further improves the tunneling efficiency of the tunnel junction 320.

[0068] Of course, during the growth of the second type semiconductor layer 121 in the second type doped layer 12, a high-low phase pulse method can also be used, so that the second type semiconductor layer 121 includes alternating layers of a first sub-semiconductor layer 121A and a second sub-semiconductor layer 121B, wherein the doping concentration of the first sub-semiconductor layer 121A is greater than the doping concentration of the second sub-semiconductor layer 121B, and the doping concentration of the first sub-semiconductor layer 121A is not less than 5E19cm⁻¹. -3 The doping concentration of the second sub-semiconductor layer 121B is not less than 1E19cm. -3 Furthermore, during the growth of the first type semiconductor layer 111 in the first type doped layer 11, a high-low phase pulse method is employed, such that the first type semiconductor layer 111 includes alternating layers of a third sub-semiconductor layer 111A and a fourth sub-semiconductor layer 111B. The doping concentration of the third sub-semiconductor layer 111A is greater than that of the fourth sub-semiconductor layer 111B, and the doping concentration of the third sub-semiconductor layer 111A is not less than 5E19cm⁻¹. -3 The doping concentration of the fourth sub-semiconductor layer 111B is not less than 1E19cm.-3 This configuration allows for two advantages: first, it simultaneously increases the overall doping concentration of the second type semiconductor layer 121 and the overall doping concentration of the first type semiconductor layer 111; second, it simultaneously balances the crystal quality of the second type semiconductor layer 121 and the crystal quality of the first type semiconductor layer 111, preventing or reducing the trapping of carriers in the second type semiconductor layer 121 and the first type semiconductor layer 111; thereby further improving the tunneling efficiency of the tunneling unit 10, and further improving the tunneling efficiency of the tunnel junction 320.

[0069] It should be noted that since the high-low phase doping in the second type semiconductor layer 121 is achieved during the growth of the second type semiconductor layer 121, similarly, the high-low phase doping in the first type semiconductor layer 111 is also achieved during the growth of the first type semiconductor layer 111. This can be combined with setting a second type strain layer 122 on the side of the second type semiconductor layer 121 near the first type doped layer 11, and setting a first type strain layer 112 on the side of the first type semiconductor layer 111 near the second type doped layer 12. It can also be combined with performing second type delta doping on the portion of the second type doped layer 12 near the first type doped layer 11, and performing first type delta doping on the portion of the first type doped layer 11 near the second type doped layer 12.

[0070] In this embodiment of the application, optionally, the tunnel junction 320 may include a tunneling unit 10, such as... Figures 1-5 As shown; another option, such as Figure 6 As shown, Figure 6 A cross-sectional schematic diagram of another vertical-cavity surface-emitting laser provided in this application embodiment is shown. It can be seen that the tunnel junction 320 may also include at least two stacked tunneling units 10, which can further improve tunneling efficiency. When the tunnel junction 320 includes at least two stacked tunneling units 10, the thickness and doping condition of the second-type doped layer 12 in each tunneling unit 10 can be the same or different. Similarly, the thickness and doping condition of the first-type doped layer 11 in each tunneling unit 10 can be the same or different, only the material of each tunneling unit 10 is recycled.

[0071] In this embodiment, the thickness of the tunnel junction 320 is no greater than 200 nm, and the ratio of the thickness of the second type doped layer 12 to the thickness of the first type doped layer is no less than 1 / 4 and no greater than 4, which can be determined according to the specific situation of the first type doping and the second type doping.

[0072] In this embodiment of the application, if the second type semiconductor layer 121 in the second type doped layer 12 is a material layer containing Al, then the Al content of the second type semiconductor layer 121 should not be greater than 42% as much as possible; similarly, if the first type semiconductor layer 111 in the first type doped layer 11 is a material layer containing Al, then the Al content of the first type semiconductor layer 111 should not be greater than 42% as much as possible.

[0073] In this embodiment, the vertical cavity surface-emitting laser may further include a second type conductive layer 330 located on the side of the light-emitting unit 310 away from the substrate and the side of the tunnel junction 320 near the substrate, and a first type conductive layer 340 located on the side of the tunnel junction 320 away from the substrate and the side of the light-emitting unit 310 near the substrate; wherein, the second type conductive layer 330 may also include a DBR reflective structure.

[0074] Accordingly, embodiments of this application also provide a method for fabricating a vertical-cavity surface-emitting laser, referencing... Figures 1-6 As shown, the method includes:

[0075] S100: Provides substrate 100;

[0076] S200: A first type reflective layer 200, a resonant cavity layer 300, and a second type reflective layer 400 are formed on one side of the substrate 100; the resonant cavity layer 300 includes at least two active layers 311, and a tunnel junction 320 is disposed between two adjacent active layers 311. The tunnel junction 320 includes at least one tunneling unit 10. The tunneling unit 10 includes a second type doped layer 12 and a first type doped layer 11 stacked sequentially. The second type doped layer 12 includes a second type semiconductor layer 121, and the first type doped layer 11 includes a first type semiconductor layer 111.

[0077] The second type doped layer 12 further includes a second type strain layer 122 located on the side of the second type semiconductor layer 121 close to the first type doped layer 11, and / or the first type doped layer 11 further includes a first type strain layer 112 located on the side of the first type semiconductor layer 111 close to the second type doped layer 12.

[0078] In this embodiment, the resonant cavity layer 300 includes at least two stacked light-emitting units 310. Each light-emitting unit 310 includes an active layer 311, and a tunnel junction 320 is disposed between two adjacent light-emitting units 310. Thus, two adjacent active layers 311 (or two adjacent light-emitting units 310) are connected in series through the tunnel junction 320, so that each active layer 311 (or each light-emitting unit 310) is connected in series to improve the power density and photoelectric conversion efficiency of the laser.

[0079] In fact, in addition to the active layer 311, the light-emitting unit 310 also includes a first type waveguide layer 312 located on the side of the active layer 311 close to the substrate 100, a second type waveguide layer 313 located on the side of the active layer 311 away from the substrate 100, and a second type oxide layer 314 located on the side of the second type waveguide layer 313 away from the active layer 311.

[0080] The method for fabricating a vertical-cavity surface-emitting laser provided in this application embodiment involves adding a second-type strain layer 122 to the tunneling unit 10 of the tunnel junction 320 on the side of the second-type semiconductor layer 121 close to the first-type semiconductor layer 111. This introduces strain through the second-type strain layer 122, changing the internal strain of the second-type semiconductor layer 121 and introducing strain at the interface between the second-type doped layer 12 and the first-type doped layer 11. Alternatively, a first-type strain layer 112 can be added to the side of the first-type semiconductor layer 111 close to the second-type semiconductor layer 121 to introduce strain. This changes the internal strain of the first-type strain layer 112 and introduces strain at the interface between the first-type doped layer 11 and the second-type doped layer 12, thereby improving the tunneling efficiency of the tunneling unit 10 and the tunnel junction 320, thus improving the performance of the multi-junction vertical-cavity surface-emitting laser.

[0081] Optionally, the thickness of the second type strain layer 122 may not be greater than 1 / 3 of the thickness of the second type semiconductor layer 121, that is, the thickness of the second type strain layer 122 is relatively thin, so as to be able to introduce strain as a strain layer.

[0082] Optionally, the second type strain layer 122 is a material layer containing In elements, and the In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121. Specifically, if the second type semiconductor layer 121 is a material layer that does not contain In elements, then the second type strain layer 122 is a material layer containing In elements; if the second type semiconductor layer 121 is a material layer that contains In elements, then the second type strain layer 122 is a material layer that contains In elements, and the In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121. In short, the In composition of the second type strain layer 122 is greater than the In composition of the second type semiconductor layer 121 (which can be 0). With this configuration, the second type strain layer 122 can introduce strain through In elements, and the magnitude of the introduced strain can be adjusted by adjusting the In composition.

[0083] Optionally, the thickness of the first type of strain layer 112 may not be greater than 1 / 3 of the thickness of the first type of semiconductor layer 111, that is, the thickness of the first type of strain layer 112 is relatively thin, so as to be able to introduce strain as a strain layer.

[0084] Optionally, the first type strain layer 112 is a material layer containing In elements, and the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111. Specifically, if the first type semiconductor layer 111 is a material layer that does not contain In elements, then the first type strain layer 112 is a material layer containing In elements; if the first type semiconductor layer 111 is a material layer that contains In elements, then the first type strain layer 112 is a material layer that contains In elements, and the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111. In short, the In composition of the first type strain layer 112 is greater than the In composition of the first type semiconductor layer 111 (which can be 0). With this configuration, the first type strain layer 112 can introduce strain through In elements, and the magnitude of the introduced strain can be adjusted by adjusting the In composition.

[0085] Optional, such as Figure 4 As shown, the formation process of the second-type doped layer 12 in the tunneling unit 10 includes:

[0086] S10: First, grow the type II doped layer 12 epitaxially;

[0087] S11: Then, stop the growth, lower the reaction chamber temperature, and perform second-type δ doping on the surface of the second-type doped layer 12 away from the substrate 100 (i.e., the surface of the second-type doped layer 12 facing the first-type doped layer 11), that is, perform second-type δ doping on the part of the second-type doped layer 12 close to the first-type doped layer 11.

[0088] By performing second-type delta doping on the surface of the second-type doped layer 12 away from the substrate 100, after the impurity atoms diffuse, they can be concentrated in a range of several atomic layers, such as greater than 1E21 cm, near the surface of the first-type doped layer 11 of the second-type doped layer 12. -3 The high-concentration doping is structurally manifested as follows: the second-type doped layer 12 includes a first portion B1 close to the first-type doped layer 11 and a second portion B2 far from the first-type doped layer 11. The doping concentration of the first portion B1 is greater than that of the second portion B2, and the thickness of the first portion B1 is no greater than 1.5 nm. With this configuration, due to the concentration of doped material within a few atomic layers of the second-type doped layer 12 near the surface of the first-type doped layer 11, the doping concentration is greater than 1E21 cm⁻¹. -3 The high concentration of doping allows for the formation of a localized high electric field within a few atomic layers of the second type doped layer 12 near the surface of the first type doped layer 11, thereby enhancing tunneling efficiency.

[0089] And / or, the formation process of the first type doped layer 11 includes:

[0090] S20: First, grow a partial type-1 doped layer epitaxially;

[0091] S21: Then, stop the growth, lower the reaction chamber temperature, and perform type δ doping on the surface of the grown type 1 doped layer away from the substrate 100.

[0092] S22: Next, the remaining type I doped layer is epitaxially grown.

[0093] By performing first-type delta doping on the surface of the first-type doped layer away from the substrate 100, followed by impurity atom diffusion and epitaxial growth of the remaining first-type doped layer, it is possible to concentrate impurity atoms within a few atomic layers of the first-type doped layer 11 near the surface of the second-type doped layer 12, such as a concentration greater than 1E21 cm. -3 The high-concentration doping is structurally manifested as follows: the first-type doped layer 11 includes a third portion B3 close to the second-type doped layer 12 and a fourth portion B4 far from the second-type doped layer 12. The doping concentration of the third portion B3 is greater than that of the fourth portion B4, and the thickness of the third portion B3 is no greater than 1.5 nm. With this configuration, due to the concentration of particles larger than 1E21 cm in a few atomic layers near the surface of the first-type doped layer 11 close to the second-type doped layer 12... -3 The high concentration of doping allows for the formation of a localized high electric field within a few atomic layers of the surface of the first type doped layer 11 near the surface of the second type doped layer 12, thereby enhancing tunneling efficiency.

[0094] Optional, such as Figure 5 As shown, during the growth of the second type semiconductor layer 121 in the second type doped layer 12, a high-low phase pulse method can be used, such that the second type semiconductor layer 121 includes alternating layers of a first sub-semiconductor layer 121A and a second sub-semiconductor layer 121B. The doping concentration of the first sub-semiconductor layer 121A is greater than that of the second sub-semiconductor layer 121B, and the doping concentration of the first sub-semiconductor layer 121A is not less than 5E19cm⁻¹. -3 The doping concentration of the second sub-semiconductor layer 121B is not less than 1E19 cm⁻¹. -3 With this configuration, the doping concentrations of the second type semiconductor layer 121 are arranged in alternating high and low concentrations. First, this can increase the overall doping concentration of the second type semiconductor layer 121. Second, it can also prevent excessively high doping concentrations of the second type semiconductor layer 121 from causing epitaxial crystal defects or dopant precipitation, thus balancing the crystal quality of the second type semiconductor layer 121 and preventing or reducing the trapping of charge carriers in the second type semiconductor layer 121. This improves the tunneling efficiency of the tunneling unit 10, and further improves the tunneling efficiency of the tunnel junction 320.

[0095] And / or, during the growth of the first type semiconductor layer 111 in the first type doped layer 11, a high-low phase pulse method may be used, such that the first type semiconductor layer 111 includes alternating layers of a third sub-semiconductor layer 111A and a fourth sub-semiconductor layer 111B, wherein the doping concentration of the third sub-semiconductor layer 111A is greater than the doping concentration of the fourth sub-semiconductor layer 111B, and the doping concentration of the third sub-semiconductor layer 111A is not less than 5E19cm⁻¹. -3 The doping concentration of the fourth sub-semiconductor layer 111B is not less than 1E19cm. -3 With this configuration, the doping concentrations of the first type semiconductor layer 111 are arranged in alternating high and low concentrations. First, this can increase the overall doping concentration of the first type semiconductor layer 111. Second, it can also prevent excessively high doping concentrations of the first type semiconductor layer 111 from causing epitaxial crystal defects or doping impurities to precipitate, thus balancing the crystal quality of the first type semiconductor layer 111 and preventing or reducing the trapping of carriers in the first type semiconductor layer 111. This improves the tunneling efficiency of the tunneling unit 10, and further improves the tunneling efficiency of the tunnel junction 320.

[0096] Since the specific structure of the vertical cavity surface-emitting laser fabricated by the method provided in this application has been described in detail in the foregoing embodiments, it can be referred to the foregoing embodiments and will not be repeated here.

[0097] The various parts of this manual are described in a combination of parallel and progressive methods. Each part focuses on the differences between the other parts, and the same or similar parts can be referred to each other.

[0098] The features described above regarding the disclosed embodiments can be substituted or combined with each other to enable those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vertical cavity surface emitting laser, characterized by, Includes a substrate and a first type reflective layer, a resonant cavity layer, and a second type reflective layer stacked on one side of the substrate; The resonant cavity layer includes at least two active layers, and a tunneling junction is disposed between two adjacent active layers. The tunneling junction includes at least one tunneling unit, and the tunneling unit includes a second type doped layer and a first type doped layer stacked in sequence. The second type doped layer includes a second type semiconductor layer, and the first type doped layer includes a first type semiconductor layer. The second type doped layer further includes a second type strain layer located on the side of the second type semiconductor layer near the first type doped layer, and / or the first type doped layer further includes a first type strain layer located on the side of the first type semiconductor layer near the second type doped layer.

2. The vertical cavity surface emitting laser according to claim 1, characterized in that The thickness of the second type of strain layer is no greater than 1 / 3 of the thickness of the second type of semiconductor layer; The thickness of the first type of strain layer is no greater than 1 / 3 of the thickness of the first type of semiconductor layer.

3. The vertical cavity surface emitting laser of claim 1, wherein, The second type semiconductor layer is an arsenide layer or an indium arsenide layer, and the second type strain layer is an indium arsenide layer; or, the second type semiconductor layer is a phosphide layer, and the second type strain layer is an indium phosphide layer; The first type of semiconductor layer is an arsenide layer or an indium arsenide layer, and the first type of strain layer is an indium arsenide layer; or, the first type of semiconductor layer is a phosphide layer or an indium phosphide layer, and the first type of strain layer is an indium phosphide layer.

4. The vertical cavity surface emitting laser according to claim 3, characterized in that The second type of semiconductor layer is a GaAs layer, GaInAs layer, AlGaAs layer, AlGaInAs layer, GaAsP layer, GaInAsP layer, AlGaAsP layer, AlGaInAsP layer, AlGaInP layer, AlGaInP layer, or GaInP layer; The first type of semiconductor layer is a GaAs layer, GaInAs layer, AlGaAs layer, AlGaInAs layer, GaAsP layer, GaInAsP layer, AlGaAsP layer, AlGaInAsP layer, AlGaInP layer, AlGaInP layer, or GaInP layer.

5. The vertical cavity surface emitting laser of claim 1, wherein, The second type of doped layer includes a first portion close to the first type of doped layer and a second portion away from the first type of doped layer, wherein the doping concentration of the first portion is greater than that of the second portion, and the thickness of the first portion is no greater than 1.5 nm; And / or, the first type of doped layer includes a third portion close to the second type of doped layer and a fourth portion far from the second type of doped layer, wherein the doping concentration of the third portion is greater than that of the fourth portion, and the thickness of the third portion is not greater than 1.5 nm.

6. The vertical cavity surface emitting laser of claim 1, wherein, The second type of semiconductor layer includes alternating layers of a first sub-semiconductor layer and a second sub-semiconductor layer, wherein the doping concentration of the first sub-semiconductor layer is greater than that of the second sub-semiconductor layer, and the doping concentration of the first sub-semiconductor layer is not less than 5E19cm⁻¹. -3 The doping concentration of the second sub-semiconductor layer is not less than 1E19cm. -3 ; And / or, the first type of semiconductor layer includes alternately stacked third and fourth sub-semiconductor layers, wherein the doping concentration of the third sub-semiconductor layer is greater than that of the fourth sub-semiconductor layer, and the doping concentration of the third sub-semiconductor layer is not less than 5E19cm⁻¹. -3 The doping concentration of the fourth sub-semiconductor layer is not less than 1E19cm. -3 .

7. The vertical cavity surface emitting laser of claim 1, wherein, The tunneling junction comprises at least two stacked tunneling units.

8. The vertical cavity surface emitting laser of claim 1, wherein, The thickness of the tunnel junction is no greater than 200 nm, and the ratio of the thickness of the second type doped layer to the thickness of the first type doped layer is no less than 1 / 4 and no greater than 4.

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