VCSEL (Vertical Cavity Surface Emitting Laser) with small divergence angle, preparation method and electronic equipment

Abstract

The invention belongs to the technical field of semiconductors, and particularly relates to a VCSEL laser with a small divergence angle, which comprises a substrate layer, a first Bragg reflector arranged on the substrate layer, an active region arranged on the first Bragg reflector, and a second Bragg reflector arranged above the active region, wherein a current limiting layer for blocking current to enable the current to enter the active area in a concentrated manner is arranged above the active area, a limiting hole for the current and laser to pass through is formed in the current limiting layer, a light emitting area is defined by the limiting hole, and at least one sharp corner is arranged on the limiting hole. On the premise that the equivalent limiting holes are the same, multilateral or irregular limiting holes with sharp-corner outlines are formed through mask pattern design in combination with ion implantation or etching and oxidation processes, so that the high-order film state can be inhibited, and the divergence angle can be reduced.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to a VCSEL laser with a small divergence angle, a preparation method and an electronic device. Background Art

[0002] VCSEL (Vertical-Cavity Surface-Emitting Laser) is a semiconductor laser that emits laser light in a direction perpendicular to the substrate. It is widely used as a light source because of its small divergence angle, small active area, easy to achieve single longitudinal mode, low threshold, and the ability to emit light in a two-dimensional array. For example, VCSEL is used as a light source for data transmission in data centers for short-distance data transmission; for another example, as a light source for vehicle-mounted laser radar, it is used for high-precision three-dimensional ranging at the sub-millimeter level for intelligent driving of vehicles.

[0003] Specifically, VCSEL mainly includes N-DBR (i.e., N-type doped Bragg reflector), P-DBR (i.e., P-type doped Bragg reflector), oxide confinement layer, multi-quantum well, active region and ohmic contact electrode. The pump source inputs current through the ohmic contact electrode, and the electrical energy is converted into light energy in the active region. The generated photons are emitted perpendicular to the active region and reflected by the P-DBR and N-DBR. When the reflected light passes through the active region again, it will stimulate the multi-quantum well to emit more light, resulting in light amplification. Finally, the light forms a resonance amplification between the P-DBR and the N-DBR, forming laser emission.

[0004] The light output performance of VCSEL will affect the application effect of VCSEL. For example, when it is used as a laser light source for laser radar in three-dimensional imaging, the divergence angle of the emitted light beam (i.e., the divergence angle of VCSEL) will affect the imaging resolution of the laser radar. For another example, when VCSEL is used as a laser light source for laser radar in laser detection, its divergence angle will affect the detection distance and detection accuracy. The smaller the divergence angle of VCSEL, the longer the irradiation distance, the wider the detection range, and the higher the detection accuracy.

[0005] In the prior art, a variety of solutions have been proposed to reduce the divergence angle of VCSEL, but there are many problems. For example, the far-field emission angle of VCSEL is related to the design of the epitaxial stack structure of VCSEL. Adjusting the VCSEL epitaxial stack design and suppressing the high-order transverse mode of VCSEL can reduce the divergence angle of VCSEL; however, suppressing the high-order transverse mode of VCSEL is difficult to design and has high manufacturing costs. For another example, reducing the current input to the VCSEL chip and reducing the intensity of the laser excited by the VCSEL can also reduce the divergence angle of VCSEL, but reducing the input current will cause the optical power of VCSEL to decrease, affecting the performance of the VCSEL chip.

[0006] Therefore, an optimized VCSEL structure design scheme is needed to reduce the divergence angle of the VCSEL and ensure the VCSEL chip manufacturing cost and VCSEL chip performance.

[0007] Application Contents

[0008] One advantage of the present application is that it provides a VCSEL laser with a small divergence angle, in which, under the premise of the same equivalent limiting hole, a mask pattern design is used in combination with ion implantation or etching + oxidation process to form a polygonal or irregular limiting hole with a sharp-angle profile, which can suppress high-order film states and reduce the divergence angle.

[0009] Another advantage of the present application is that it provides a VCSEL laser with a small divergence angle, wherein the VCSEL chip can still use the traditional VCSEL preparation process during the preparation process, and only needs to adjust the shape of the limiting hole. In this way, the original VCSEL production line and production equipment can be retained to use them to prepare the VCSEL laser of the present application, effectively reducing the production line modification cost of the VCSEL laser, and thereby reducing the preparation cost of the VCSEL laser.

[0010] In order to achieve at least one of the above advantages or other advantages and purposes, according to one aspect of the present application, a VCSEL laser with a small divergence angle is provided, which includes a substrate layer, a first Bragg reflector arranged on the substrate layer, an active region arranged on the first Bragg reflector, and a second Bragg reflector arranged above the active region; wherein,

[0011] A current limiting layer is provided above the active area to block the current so that the current can be concentrated into the active area. The current limiting layer has a limiting hole for the current and laser to pass through. The limiting hole defines the light-emitting area and has at least one sharp corner.

[0012] In the VCSEL laser with a small divergence angle described in the present application, the limiting hole has N sharp corners, wherein 3≤N≤10.

[0013] In the VCSEL laser with a small divergence angle according to the present application, the limiting hole is a polygonal hole formed by a water oxidation process or an ion implantation process.

[0014] In the VCSEL laser with a small divergence angle described in the present application, the limiting hole is one of a triangle, a quadrilateral, a pentagon, and a hexagon.

[0015] In the VCSEL laser with a small divergence angle described in the present application, the current limiting layer is an oxidized limiting layer, and the limiting hole is formed on the oxidized limiting layer; and an etched hole or an etched groove is arranged outside the limiting hole for oxidizing to form a limiting hole of a specified shape, wherein at least one of the multiple inner walls of the etched hole or the etched groove close to one side of the limiting hole is a straight wall.

[0016] In the VCSEL laser with a small divergence angle described in the present application, the current limiting layer is an ion implantation layer, and the limiting hole is a region on the ion implantation layer where ions are not implanted.

[0017] In the VCSEL laser with a small divergence angle described in the present application, the current confinement layer is an ion implantation layer and an oxidation confinement layer, wherein the oxidation confinement layer is located in the middle of the ion implantation layer.

[0018] In the VCSEL laser with a small divergence angle described in the present application, the current confinement layer is an ion implantation layer and an oxidation confinement layer, wherein the oxidation confinement layer is located above or below the ion implantation layer.

[0019] In the VCSEL laser with a small divergence angle described in the present application, the ion implantation layer has an area A that is not implanted with ions, and the oxidation restriction layer has an area B that is not oxidized. In the top view direction, the overlapping portion of the area A and the area B forms the restriction hole.

[0020] Another aspect of the present application provides a process for manufacturing a VCSEL laser with a small divergence angle, which comprises the following steps:

[0021] S10, forming an epitaxial main structure by an epitaxial growth process, wherein the epitaxial main structure includes a substrate structure layer, a first Bragg reflection structure layer, an active structure layer, and a second Bragg reflection structure layer;

[0022] S20, forming a P-type metal structure layer deposited on the epitaxial main structure;

[0023] S30, etching and removing at least a portion of the epitaxial structure to form at least one light-emitting unit, wherein each of the light-emitting units includes a substrate layer, a first Bragg reflector, an active region, a second Bragg reflector, and a P-type metal;

[0024] S40, forming a current limiting layer above the active area by etching holes or etching trenches in combination with a water oxidation process or an ion implantation process, wherein the current limiting layer has a limiting hole for current to pass through and enter the active area, wherein the limiting hole has at least one sharp corner;

[0025] S50, defining the shape of the P-type metal layer to form a P-type ohmic contact layer;

[0026] S60, forming a positive electrode electrically connected to the P-type ohmic contact layer; and

[0027] S70, grinding and thinning the substrate layer, and then depositing an N-type metal on the bottom surface of the substrate layer to form a negative electrode.

[0028] According to another aspect of the present application, the present application provides an electronic device, comprising:

[0029] A laser projection device for projecting laser light, wherein the laser projection device comprises any high optical power VCSEL chip as described above;

[0030] a laser receiving device for receiving a laser signal; and

[0031] A processor is communicatively connected to the laser projection device and the laser receiving device.

[0032] Further objectives and advantages of the present application will be fully reflected through understanding of the following description and drawings.

[0033] These and other objects, features and advantages of the present application are fully reflected in the following detailed description, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of multiple light-emitting units of a VCSEL laser with a small divergence angle of the present application.

[0035] Figure 2 Schematic diagram of a single light-emitting unit of a VCSEL laser with a small divergence angle of the present application.

[0036] Figure 3-1 A schematic diagram of a light-emitting unit of the present application forming an oxidized limiting layer with a limiting hole by water oxidation, wherein the limiting hole is a corner in the top view direction

[0037] Figure 3-2 A schematic diagram of a light-emitting unit of the present application forming an oxidized limiting layer with limiting holes by water oxidation, wherein the limiting holes are triangular in the top view direction

[0038] Figure 3-3 A schematic diagram of a light-emitting unit of the present application forming an oxidized limiting layer having limiting holes by water oxidation, wherein the limiting holes are hexagonal in a plan view.

[0039] Figure 4-1 This is a schematic diagram showing that a light emitting unit of the present application forms a limiting hole by ion implantation, and the limiting hole is a corner in a top view direction.

[0040] Figure 4-2This is a schematic diagram of a light emitting unit of the present application that forms a limiting hole by ion implantation, and the limiting hole is a triangle in a top view direction.

[0041] Figure 4-3 This is a schematic diagram showing that the light-emitting unit of the present application forms a limiting hole through ion implantation, and the limiting hole is a hexagonal shape when viewed from above.

[0042] Figure 5-1 This is a schematic diagram in a top view showing that the area of ​​the ion implantation forming region A of the light emitting unit of the present application is smaller than the water oxidation forming region B, and the limiting hole is a corner.

[0043] Figure 5-2 This is a schematic diagram of a top view of a light-emitting unit in which the area of ​​the ion implantation forming region A is smaller than the water oxidation forming region B and the limiting hole is a triangle.

[0044] Figure 5-3 This is a schematic diagram of a top view showing that the area of ​​the ion implantation forming region A of the light emitting unit of the present application is smaller than the water oxidation forming region B, and the limiting hole is hexagonal.

[0045] Figure 6-1 This is a schematic diagram in a top view showing that the area of ​​the ion implantation forming region A of the light emitting unit of the present application is larger than the water oxidation forming region B, and the limiting hole is an angle.

[0046] Figure 6-2 This is a schematic diagram of a top view of a light-emitting unit in which the area of ​​the ion implantation forming region A is larger than the water oxidation forming region B and the limiting hole is a triangle.

[0047] Figure 6-3 This is a schematic diagram of a top view showing that the area of ​​the ion implantation forming region A of the light emitting unit of the present application is larger than the water oxidation forming region B, and the limiting hole is hexagonal.

[0048] Figure 7-1 This is a schematic diagram in the top view that the area A formed by ion implantation and the area B formed by water oxidation of the light-emitting unit of the present application are of the same size, and the limiting hole is an angle.

[0049] Figure 7-2 This is a schematic diagram in the top view of the light-emitting unit of the present invention in which the area A formed by ion implantation and the area B formed by water oxidation are of the same size and the limiting hole is a triangle.

[0050] Figure 7-3 This is a schematic diagram showing that the area A formed by ion implantation and the area B formed by water oxidation of the light-emitting unit of the present application are of the same size, and the limiting hole is hexagonal in a top view. DETAILED DESCRIPTION

[0051] The terms and words used in the following specification and claims are not limited to the literal meanings, but are merely used by the applicant to enable a clear and consistent understanding of the present application. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of the present application is provided for illustration purposes only and not for the purpose of limiting the present application as defined by the appended claims and their equivalents.

[0052] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0053] Although ordinals such as "first," "second," and the like will be used to describe various components, those components are not limited herein. The term is used only to distinguish one component from another. For example, a first component may be referred to as a second component, and likewise, a second component may be referred to as a first component without departing from the teachings of the present application. The term "and / or" as used herein includes any and all combinations of one or more associated listed items.

[0054] The terms used herein are only used for the purpose of describing various embodiments and are not intended to be limiting. As used herein, singular forms are intended to include plural forms, unless the context clearly indicates an exception. It will also be understood that the terms "comprising" and / or "having" when used in this specification specify the presence of the described features, numbers, steps, operations, components, elements, or combinations thereof, without excluding the presence or addition of one or more other features, numbers, steps, operations, components, elements, or groups thereof.

[0055] Application Overview

[0056] As mentioned above, the light emitting performance of VCSEL will affect the effect of its application. For example, as the laser light source of laser radar, it is used for high-precision three-dimensional ranging and three-dimensional imaging. The divergence angle of the emitted light beam (i.e., the divergence angle of VCSEL) will affect the detection distance and imaging resolution of the laser radar. Specifically, in the three-dimensional ranging and three-dimensional imaging of the laser radar, the size of the divergence angle is negatively correlated with the three-dimensional ranging and three-dimensional imaging of the laser radar.

[0057] In order to reduce the divergence angle of VCSEL and improve the performance of VCSEL, a variety of schemes are currently used in the design of VCSEL, among which the transverse mode of the light beam emitted by VCSEL will affect the divergence angle of VCSEL. The transverse mode can reflect the energy distribution pattern of the light spot projected by VCSEL on the cross section perpendicular to the cavity axis of the resonant cavity of VCSEL. The transverse mode is divided into the fundamental mode and the high-order mode. The energy distribution of the high-order transverse mode is more complex, and the corresponding light beam has a larger divergence angle. Accordingly, the divergence angle of VCSEL can be reduced by effectively selecting, controlling or suppressing the transverse mode technology.

[0058] The present application proposes to form a polygonal oxidation aperture or an irregular oxidation aperture with sharp corners by designing a VCSEL mask under the premise of an equivalent oxidation aperture, in combination with an ion implantation process or an etching oxidation process. The sharp corners on the oxidation aperture can suppress high-order modes, reduce the VCSEL divergence angle, and improve the performance of the VCSEL.

[0059] Based on this, according to one aspect of the present application, the present application proposes a VCSEL laser with a small divergence angle, which includes a substrate layer, a first Bragg reflector, a second Bragg reflector, an active area, an oxidation restriction layer and / or an ion implantation layer, wherein the active area, the oxidation restriction layer and / or the ion implantation layer are sandwiched between the first Bragg reflector and the second Bragg reflector, and the oxidation restriction layer and / or the ion implantation layer form a restriction hole for current to pass through, and the edge of the restriction hole has at least one angle.

[0060] After introducing the basic principles of the present application, various non-limiting embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0061] like Figure 1 and Figure 2 As shown, the VCSEL laser 1 of this embodiment is composed of a plurality of light-emitting units 10; or in other modified embodiments, the VCSEL laser may be a single light-emitting unit 10. The light-emitting unit 1 includes, from bottom to top, a substrate layer 11, a first Bragg reflector 12, an active region 13, a current limiting layer 14, a second Bragg reflector 15, a first electrode 16, and a second electrode 17; wherein the active region 13 is sandwiched between the first Bragg reflector 12 and the second Bragg reflector 15 to form a resonant cavity, and after being excited, photons are reflected back and forth in the resonant cavity and repeatedly amplified to form laser oscillation, thereby forming laser emission.

[0062] Specifically, the substrate layer 11 is an N-type gallium arsenide substrate. In other embodiments, the substrate layer can also be a P-type gallium arsenide substrate. The first Bragg reflector 12 is grown on the substrate layer 11 by MOCVD technology. The first electrode 16 is deposited on the bottom surface of the substrate layer 11. The first electrode is an N-type metal. The active region 13 is grown on the first Bragg reflector 12 by MOCVD, and the second Bragg reflector 15 is grown on the active region. The second electrode 17 is deposited on the top surface of the second Bragg reflector 15. The second electrode is a P-type metal.

[0063] Specifically, the first Bragg reflector 12 and the second Bragg reflector 15 are a system composed of alternating layers of materials with different refractive indices, and the system forms a distributed Bragg reflector (Distributed Bragg Reflector). The material selection of the alternating layers depends on the required working wavelength of the laser. Among them, in this embodiment, the first Bragg reflector 12 is an N-DBR, and the second Bragg reflector 15 is a P-DBR; or in other implementations, the first Bragg reflector can be a P-DBR, and the second Bragg reflector is an N-DBR. In a specific example of the present application, the P-DBR is formed by alternating stacks of multiple P-type doped high aluminum content AlxGa1-xAs (x=1~0) and P-type doped low aluminum content AlxGa1-xAs (x=1~0); the N-DBR is formed by alternating stacks of N-type doped high aluminum content AlxGa1-xAs (x=1~0) and N-type doped low aluminum content AlxGa1-xAs (x=1~0). It is worth mentioning that the material selection of the alternating layer depends on the working wavelength of the laser emitted by the VCSEL light-emitting point, and the optical thickness of the alternating layer is equal to or approximately equal to 1 / 4 of the working wavelength of the laser.

[0064] In addition, the active region 13 is sandwiched between the second Bragg reflector 15 and the first Bragg reflector 12 to form a resonant cavity, wherein photons are reflected back and forth in the resonant cavity after being excited and are repeatedly amplified to form laser oscillation to form laser. A person skilled in the art should know that the emission direction of the laser can be selectively controlled by configuring and designing the second Bragg reflector 15 and the first Bragg reflector 12, for example, emitting from the second Bragg reflector (i.e., emitting from the top surface of the VCSEL laser) or, emitting from the first Bragg reflector (i.e., emitting from the bottom surface of the VCSEL laser).

[0065] In the embodiment of the present application, the second Bragg reflector 15 and the first Bragg reflector 12 are designed so that the laser is emitted from the second Bragg reflector after oscillating in the resonant cavity, that is, the VCSEL laser is a semiconductor laser that emits light from the front. In the embodiment of the present application, the second Bragg reflector 15, the current limiting layer 14, the active region 13 and the first Bragg reflector 12 constitute the epitaxial structure of the VCSEL.

[0066] In order to limit the limiting aperture of the VCSEL, a current limiting layer 14 having a limiting hole 141 is formed on the VCSEL through a water oxidation process, and the current limiting layer 14 is an oxidation limiting layer. The oxidation limiting layer of the present application has insulating properties to block the current from passing through; the current input by the pump source enters the VCSEL and is blocked by the oxidation limiting layer, and enters the active area 13 from the limiting hole 141 through the oxidation limiting layer. In a specific embodiment of the present application, the oxidation limiting layer can be formed as a separate layer above the active area 13, or it can be formed above the active area 13 by oxidizing at least a portion of the lower area of ​​the P-DBR layer, which is not limited to the present application.

[0067] It is worth mentioning that in the application of VCSEL lasers, the divergence angle of VCSEL will affect its application effect. For example, the divergence angle of VCSEL is related to the imaging resolution. Specifically, the smaller the divergence angle of VCSEL, the higher the imaging resolution, which is beneficial to the long-range data detection of laser radar. For another example, the smaller the divergence angle of VCSEL, the longer the irradiation distance, the wider the detection range, and the higher the detection accuracy. In the study of the influencing factors of the divergence angle of VCSEL, it was found that the transverse mode of the light beam emitted by VCSEL will affect the divergence angle of VCSEL, that is, the energy distribution of high-order transverse modes is more complex, which will cause the divergence angle of the light beam to become larger. Therefore, the divergence angle of VCSEL can be effectively reduced by effectively selecting, controlling or suppressing high-order transverse modes.

[0068] In order to reduce the divergence angle, the present application proposes to suppress high-order transverse modes by changing the shape of the limiting hole 141 to reduce the divergence angle of the VCSEL; in the embodiment of the present application, the shape of the limiting hole 141 is defined as a limiting hole with at least one sharp corner. After the current enters the VCSEL, it will enter the active area along the shortest path. The current gathers at the sharp corner position of the limiting hole 141. The current density at the edge of the limiting hole 141 is greater than that in other non-sharp-cornered areas. The increase in the number of electrons will block the light emitted by the VCSEL, thereby concentrating the light beam and reducing the divergence angle.

[0069] In one embodiment of the present application, the manufacturing process of the VCSEL chip includes mask design, etching holes or trenches, water oxidation to form limiting holes, deposition of protective layer, P-type metal deposition, grinding and thinning, N-type metal deposition, testing, and cutting. Among them, the oxidation limiting layer 14a is formed by water oxidation of the inner wall of the hole or trench into the interior of the epitaxial wafer, and then forming an oxidation limiting layer 14a with limiting holes, and the limiting holes formed on the oxidation limiting layer 14a are non-circular limiting holes with sharp corners, and the limiting holes have n sharp corners, where n is a positive integer, and n is preferably 3 to 10, and its specific number is not specifically limited.

[0070] like Figure 3-1 As shown, in a preferred embodiment of the present application forming a limiting hole by water oxidation, the number of the limiting hole is 1, corresponding to forming a water drop-shaped limiting hole 141a; the hole or trench formed to form the limiting hole 141a is in a water drop shape or a water drop-like shape. Figure 3-2 As shown, in another preferred embodiment of the present application, the limiting hole 141b is formed by water oxidation, and the limiting hole 141b has three sharp corners, and the corresponding limiting hole 141b is triangular or approximately triangular in shape; three holes arranged along the triangle are formed by etching, and then water oxidation is performed to form a triangular limiting hole; or a triangular trench is etched on the epitaxial wafer, and then water oxidation is performed to form a triangular limiting hole. Figure 3-3 As shown, in the optimal embodiment of the present application for forming a limiting hole by water oxidation, the limiting hole 141c is in the shape of a hexagon, which has six sharp corners corresponding to the limiting hole 141c; six holes arranged along the hexagon are formed by etching, and then water oxidation is performed to form a hexagonal limiting hole; or a hexagonal trench is etched on the epitaxial wafer, and then water oxidation is performed to form a hexagonal limiting hole.

[0071] In other embodiments of the present application, the manufacturing process of the VCSEL chip includes mask design, ion implantation to form a limiting hole with an ion implantation layer, deposition of a protective layer, P-type metal deposition, grinding and thinning, N-type metal deposition, testing, and cutting. In the present application, hydrogen ions are accelerated by a high-energy electric field and injected into the epitaxial wafer to form an ion implantation layer 14b in the epitaxial wafer. The ion implantation layer 14b forms an insulating region on the epitaxial wafer to block the current pumped into the VCSEL from passing through. In the present application, a portion of the ion implantation layer 14b is not implanted with hydrogen ions, and the region not implanted with hydrogen ions is formed as a limiting hole, so the shape of the limiting hole is defined by the shape of the region not implanted with hydrogen ions. In the present application, the limiting hole is a non-circular limiting hole with sharp corners, wherein the sharp corners on the limiting hole are acute angles, right angles or obtuse angles, and the number of sharp corners is n, n is a positive integer, and n is preferably 3 to 10, and the specific number is not specifically limited here.

[0072] like Figure 4-1 As shown, in a preferred embodiment of the present application, the number of the limiting holes formed by ion implantation is 1, corresponding to the formation of a water drop-shaped limiting hole 141d. Figure 4-2 As shown, in another preferred embodiment of the present application, the limiting hole 141e is formed by ion implantation, and the shape of the limiting hole 141e is triangular or approximately triangular, and the limiting hole 141e has three sharp corners. Figure 4-3 As shown, in the optimal embodiment of the present application in which the limiting hole is formed by ion implantation, the limiting hole 141f is hexagonal, and has six sharp corners corresponding to the limiting hole 141f.

[0073] In other embodiments of the present application, the process technology of the VCSEL chip includes mask design, ion implantation to form an ion implantation layer, etching the epitaxial wafer to form holes or trenches, oxidation to form an oxidation restriction layer, deposition of a protective layer, P-type metal deposition, grinding and thinning, N-type metal deposition, testing, and cutting. In this embodiment, hydrogen ions are accelerated into a designated area of ​​the epitaxial wafer by a high-energy electric field to form an ion implantation layer. The ion implantation layer has insulating properties, which blocks the dispersed flow of current entering the epitaxial wafer, so that the current is concentrated in the epitaxial wafer and enters the active area. The oxidation restriction layer has the same function as the ion implantation layer, which is used to concentrate the current entering the active area. In an embodiment of the present application, the oxidation restriction layer is located in the middle of the ion implantation layer, that is, water oxidizes part of the ion implantation layer to form the oxidation restriction layer. In other embodiments, the epitaxial wafer located below the ion implantation layer is oxidized by a water oxidation process to form an oxidation restriction layer, that is, the oxidation restriction layer is located above the ion implantation layer. Alternatively, in another embodiment, the epitaxial wafer located above the ion implantation layer is oxidized by a water oxidation process to form an oxidation restriction layer; the oxidation restriction layer is located above the ion implantation layer.

[0074] In the present application, on the epitaxial wafer with an ion implantation layer and an oxidation restriction layer, in order to realize the current concentration entering the active area, the ion implantation layer is partially not implanted with hydrogen ions, and this part forms a region A in the active area for the current to pass through; the oxidation restriction layer is partially not oxidized, forming a region B for the current to pass through and enter the active area. In the top view direction, the region A and the region B overlap each other, and the overlapping part of the region A and the region B forms a restriction hole, and the current entering the epitaxial wafer is concentrated through the restriction hole to enter the active area. The shape of the restriction hole is defined by the shape of the overlapping part of the region A and the region B.

[0075] In one embodiment of the present application, the shape of the region A is circular, and the shape of the region B is non-circular with sharp corners. In the top view direction, the region B is completely located inside the region A. Therefore, the shape of the limiting hole in this embodiment is defined by the shape of the region B. In the embodiment of the present application, the limiting hole 141g (i.e., the region B) is non-circular with sharp corners, wherein the sharp corners on the limiting hole are acute angles, right angles, or obtuse angles, and the number of sharp corners is n, where n is a positive integer, and n is preferably 3 to 10, and the specific number is not specifically limited here. Specifically, Figure 5-1 As shown, the number of sharp corners on the limiting hole (ie, region B) is 1, corresponding to the formation of a water drop-shaped limiting hole 141g. Figure 5-2 As shown, in the embodiment of the present application where the limiting hole is defined by the shape of region B, the limiting hole (ie, region B) is in a triangular or approximately triangular shape, and the limiting hole has three sharp corners. Figure 5-3 As shown, in another embodiment of the present application, the limiting hole is defined by the shape of region B, and the limiting hole 141i is a hexagon, which corresponds to six sharp corners on the limiting hole. Of course, in other embodiments of the present application, the limiting hole is defined by the shape of region B, and the shape of the limiting hole can be a quadrilateral, a pentagon, a heptagon, an octagon, etc., and its shape is a shape with sharp corners, and it can be a regular or irregular shape, which will not be specifically listed here.

[0076] In another embodiment of the present application, the region A is a non-circular shape with sharp corners, the region B is the same shape as the region A or the shape of the region B is a circle, the area of ​​the region B is larger than the area of ​​the region A, and in the top view direction, the region A is completely located inside the region B, so the shape of the limiting hole in this embodiment is defined by the shape of the region A. In an embodiment of the present application, the limiting hole (i.e., the region A) is a non-circular shape with sharp corners, wherein the sharp corners on the limiting hole are acute angles, right angles, or obtuse angles, and the number of sharp corners is n, where n is a positive integer, and n is preferably 3 to 10, and the specific number is not specifically limited here. Specifically, if Figure 6-1 As shown, the number of sharp corners on the limiting hole (i.e., area A) is 1, corresponding to a water drop-shaped limiting hole. Figure 6-2 As shown, in the embodiment of the present application where the limiting hole is defined by the shape of region A, the limiting hole (ie, the region A) is in a triangular or approximately triangular shape, and the limiting hole has three sharp corners. Figure 6-3As shown, in another embodiment of the present application, the limiting hole is defined by the shape of region A, and the limiting hole is a hexagon, which corresponds to six sharp corners on the limiting hole. Of course, in other embodiments of the present application, the limiting hole is defined by the shape of region A, and the shape of the limiting hole can be a quadrilateral, a pentagon, a heptagon, an octagon, etc., and the shape is a shape with sharp corners, and it can be a regular or irregular shape, which will not be specifically listed here.

[0077] In another embodiment of the present application, the shape of region A is the same as that of region B, and the area of ​​region A is the same as that of region B, that is, in the top view direction, the edge of region A overlaps with the edge of region B. Therefore, in the present application, both region A and region B are non-circular with sharp corners, and the shape of the limiting hole is defined by the shape of region A and / or region B. In an embodiment of the present application, the limiting hole (that is, region A and region B) is a non-circular with sharp corners, wherein the sharp corners on the limiting hole are acute angles, right angles or obtuse angles, and the number of sharp corners is n, n is a positive integer, and n is preferably 3 to 10, and the specific number is not specifically limited here. Specifically, if Figure 7-1 As shown, the number of sharp corners on the limiting hole 141m (i.e., region A and region B) is 1, corresponding to a water drop-shaped limiting hole. In the embodiment of the present application, the limiting hole is defined by the shape of region A and region B. Figure 7-2 As shown, the shape of the limiting hole (ie, area A and area B) is a triangle or approximately a triangle, and the corresponding limiting hole 141n has three sharp corners. Figure 7-3 As shown, in another embodiment of the present application, the limiting hole is defined by the shape of region A and region B, and the limiting hole 141o is a hexagon, which corresponds to six sharp corners on the limiting hole. Of course, in other embodiments of the present application, the limiting hole is defined by the shape of region A and region B, and the shape of the limiting hole can be a quadrilateral, a pentagon, a heptagon, an octagon, etc., and the shape is a shape with sharp corners, and it can be a regular or irregular shape, which will not be listed here in detail.

[0078] In summary, the VCSEL laser based on the embodiment of the present application is explained, and the VCSEL laser provides a design scheme for improving the divergence angle of the VCSEL laser by limiting the shape of the hole, and by adding a sharp corner to the limiting hole, the current is concentrated at the sharp corner, thereby improving the photoelectric characteristics of the VCSEL and reducing the divergence angle.

[0079] Schematic VCSEL laser preparation method

[0080] According to another aspect of the present application, a method for preparing a VCSEL laser is also provided, which is used to prepare the VCSEL laser as described above. In an embodiment of the present application, the VCSEL laser can still use the traditional VCSEL preparation process during the preparation process, and only needs to adjust the shape of the limiting hole. In this way, the original VCSEL production line and production equipment can be retained to be used to prepare the VCSEL laser of the present application, effectively reducing the production line modification cost of the VCSEL laser, thereby reducing the preparation cost of the VCSEL laser.

[0081] Specifically, in an embodiment of the present application, the method for preparing the VCSEL laser comprises:

[0082] Follow these steps:

[0083] S10, forming an epitaxial main structure by an epitaxial growth process, wherein the epitaxial main structure includes a substrate structure layer, a first Bragg reflection structure layer, an active structure layer, and a second Bragg reflection structure layer;

[0084] S20, forming a P-type metal structure layer deposited on the epitaxial main structure;

[0085] S30, etching and removing at least a portion of the epitaxial structure to form at least one light-emitting unit, wherein each of the light-emitting units includes a substrate layer, a first Bragg reflector, an active region, a second Bragg reflector, and a P-type metal;

[0086] S40, forming a current limiting layer above the active area by etching holes or etching trenches in combination with a water oxidation process or an ion implantation process, wherein the current limiting layer has a limiting hole for current to pass through and enter the active area, wherein the limiting hole has at least one sharp corner;

[0087] S50, defining the shape of the P-type metal layer to form a P-type ohmic contact layer;

[0088] S60, forming a positive electrode electrically connected to the P-type ohmic contact layer; and

[0089] S70, grinding and thinning the substrate layer, and then depositing an N-type metal on the bottom surface of the substrate layer to form a negative electrode.

[0090] Schematic electronic equipment

[0091] According to another aspect of the present application, an electronic device is also provided. The working principle of the electronic device is: using laser as a medium, emitting laser to a target to be measured, and receiving laser reflected by the target to be measured, and based on the time difference between the emitted laser pulse and the received laser pulse (or the phase difference between the emitted laser pulse and the received reflected laser pulse), the relative position and distance between the target to be measured and the laser radar are obtained, thereby realizing detection, tracking and identification of the target to be measured in the target area.

[0092] Accordingly, the electronic device includes: a laser projection device for projecting laser, a laser receiving device for receiving laser signals, and a processor communicatively connected to the laser projection device and the laser receiving device, wherein the laser projection device includes a VCSEL chip of optical power as described above.

[0093] It should be noted that in the apparatus and method of the present application, the components or steps in different embodiments can be decomposed and / or recombined without departing from the principles of the present application. Such decomposition and / or recombination should be considered to be included in the application concept of the present application.

[0094] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

Claims

1. A VCSEL laser with a small divergence angle, wherein: The invention comprises a substrate layer, a first Bragg reflector arranged on the substrate layer, an active region arranged on the first Bragg reflector, and a second Bragg reflector arranged above the active region; wherein, A current limiting layer is provided above the active area to block the current so that the current can be concentrated into the active area. The current limiting layer has a limiting hole for the current and laser to pass through. The limiting hole defines the light-emitting area and has at least one sharp corner.

2. A VCSEL laser with a small divergence angle according to claim 1, wherein: The limiting hole has N sharp corners, wherein 3≤N≤10.

3. A VCSEL laser with a small divergence angle according to claim 1, wherein: The limiting hole is a polygonal hole formed by a water oxidation process or an ion implantation process.

4. A VCSEL laser with a small divergence angle according to claim 3, wherein: The limiting hole is one of a triangle, a quadrilateral, a pentagon and a hexagon.

5. A VCSEL laser with a small divergence angle according to claim 1, wherein: The current limiting layer is an oxidized limiting layer, and the limiting hole is formed on the oxidized limiting layer; and an etched hole or an etched groove is arranged outside the limiting hole for oxidizing to form a limiting hole of a specified shape, wherein at least one of the multiple inner walls of the etched hole or the etched groove close to one side of the limiting hole is a straight wall.

6. A VCSEL laser with a small divergence angle according to claim 1, wherein: The current limiting layer is an ion implantation layer, and the limiting hole is a region on the ion implantation layer where ions are not implanted.

7. A VCSEL laser with a small divergence angle according to claim 1, wherein: The current limiting layer is a combination of an ion implantation layer and an oxidation limiting layer, wherein the oxidation limiting layer is located in the middle of the ion implantation layer.

8. A VCSEL laser with a small divergence angle according to claim 1, wherein: The current confinement layer is a combination of an ion implantation layer and an oxidation confinement layer, wherein the oxidation confinement layer is located above or below the ion implantation layer.

9. A VCSEL laser with a small divergence angle according to claim 7 or 8, wherein: The ion implantation layer has a region A which is not implanted with ions, and the oxidation restriction layer has a region B which is not oxidized. In the plan view, the overlapping portion of the region A and the region B forms the restriction hole.

10. A process for manufacturing a VCSEL laser with a small divergence angle as claimed in claims 1 to 9, wherein: The following steps are involved: S10, forming an epitaxial main structure by an epitaxial growth process, wherein the epitaxial main structure includes a substrate structure layer, a first Bragg reflection structure layer, an active structure layer, and a second Bragg reflection structure layer; S20, forming a P-type metal structure layer deposited on the epitaxial main structure; S30, etching and removing at least a portion of the epitaxial structure to form at least one light-emitting unit, wherein each of the light-emitting units includes a substrate layer, a first Bragg reflector, an active region, a second Bragg reflector, and a P-type metal; S40, forming a current limiting layer above the active area by etching holes or etching trenches in combination with a water oxidation process or an ion implantation process, wherein the current limiting layer has a limiting hole for current to pass through and enter the active area, wherein the limiting hole has at least one sharp corner; S50, defining the shape of the P-type metal layer to form a P-type ohmic contact layer; S60, forming a positive electrode electrically connected to the P-type ohmic contact layer; and S70, grinding and thinning the substrate layer, and then depositing an N-type metal on the bottom surface of the substrate layer to form a negative electrode.

11. An electronic device, characterized in that: include: A laser projection device for projecting laser light, wherein the laser projection device comprises any one of the VCSEL lasers with a small divergence angle as claimed in claims 1 to 9; a laser receiving device for receiving a laser signal; and A processor is communicatively connected to the laser projection device and the laser receiving device.

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