Semiconductor light-emitting element

Abstract

The invention relates to a semiconductor light-emitting element which comprises a substrate, a first optical reflection part, an active light-emitting layer, a second optical reflection part, a first contact layer, a second contact layer, a first metal layer and a second metal layer. A light-emitting side of the semiconductor light-emitting element is positioned on one side, far away from the first optical reflection part, of the substrate; the active light-emitting layer, the first optical reflection part, the second optical reflection part, the first contact layer and the second contact layer are mutually overlapped along a thickness direction to form a columnar structure, and the semiconductor light-emitting element further comprises an insulating layer which at least partially covers the outer surface of the columnar structure. The insulating layer encloses a caulking groove which is opened along the thickness direction, and a connecting part of the second metal layer is embedded in the caulking groove and is connected with the second contact layer.

Description

Technical Field

[0001] The present invention relates to semiconductors, and in particular to a semiconductor light emitting element. Background Art

[0002] The vertical cavity surface emitting laser (VCSEL) in the prior art includes a light-emitting region, two distributed Bragg reflection regions located on two opposite sides of the light-emitting region, and an oxide layer adjacent to the light-emitting region. Photons resonate back and forth between the two distributed Bragg reflection regions to form a laser beam and emit it perpendicular to the top surface of the device. It has the advantages of easy manufacturing, cost saving, low divergence angle and high coupling efficiency.

[0003] In order to adjust the mode and polarization direction of the light emitted by the vertical resonant cavity surface emitting laser, the existing technology mostly suppresses the side mode by reducing the oxidized hole of the oxide layer, changing the aperture size of the light-emitting hole, or setting a grating, surface relief structure, etc., so that the light changes from multi-mode to single-mode and stabilizes the polarization direction of the light. However, the method of reducing the oxidized hole is not reliable, and will lead to problems such as reduced light output power, increased resistance of the light-emitting area, and increased thermal effect; changing the aperture size of the light-emitting hole or setting a grating, surface relief structure, etc. requires complex processing on the light-emitting surface of the vertical resonant cavity surface emitting laser, which is easy to lead to risks such as low yield and poor light output power, and there are shortcomings that need to be improved urgently.

[0004] Therefore, it is necessary to provide a novel and advanced semiconductor light emitting element to solve the above problems. Summary of the invention

[0005] The main purpose of the present invention is to provide a semiconductor light emitting element, the mode of which is consistent and the polarization direction is stable.

[0006] To achieve the above-mentioned object, the present invention provides a semiconductor light-emitting element, comprising: a substrate, a first optical reflective portion, an active light-emitting layer, a second optical reflective portion, a first contact layer, a second contact layer, a first metal layer and a second metal layer. The substrate defines a thickness direction; the first optical reflective portion is stacked on one side of the substrate along the thickness direction and includes a plurality of pairs of distributed Bragg reflectors; the active light-emitting layer is stacked on one side of the first optical reflective portion relative to the substrate; the second optical reflective portion is stacked on one side of the active light-emitting layer relative to the first optical reflective portion along the thickness direction, the second optical reflective portion includes a plurality of pairs of distributed Bragg reflectors, and a reflectivity of the second optical reflective portion is greater than a reflectivity of the first optical reflective portion; the first contact layer is disposed between the substrate and the first optical reflective portion; the second contact layer is stacked on one side of the second optical reflective portion relative to the active light-emitting layer along the thickness direction; the first metal layer is electrically connected to the first contact layer; and the second metal layer is electrically connected to the second contact layer. Wherein, a light emitting side of the semiconductor light emitting element is located on a side of the substrate away from the first optical reflective portion; the active light emitting layer, the first optical reflective portion, the second optical reflective portion, the first contact layer and the second contact layer are stacked one on another along the thickness direction to form a columnar structure, the columnar structure defines a central axis, the semiconductor light emitting element further includes an insulating layer at least partially covering the outer surface of the columnar structure, the insulating layer surrounds an embedding groove open along the thickness direction, a connecting portion of the second metal layer is embedded in the embedding groove and connected to the second contact layer; wherein the second optical reflective portion further includes a large diameter section adjacent to the active light emitting layer and a small diameter section adjacent to the second contact layer, a radial dimension of the large diameter section is greater than a radial dimension of the small diameter section.

[0007] To achieve the above-mentioned object, the present invention provides a semiconductor light-emitting element, comprising: a substrate, a first optical reflective portion, an active light-emitting layer, a second optical reflective portion, a first contact layer, a second contact layer, a first metal layer and a second metal layer. The substrate defines a thickness direction; the first optical reflective portion is stacked on one side of the substrate along the thickness direction and includes a plurality of pairs of distributed Bragg reflectors; the active light-emitting layer is stacked on one side of the first optical reflective portion relative to the substrate; the second optical reflective portion is stacked on one side of the active light-emitting layer relative to the first optical reflective portion along the thickness direction, the second optical reflective portion includes a plurality of pairs of distributed Bragg reflectors, and a reflectivity of the second optical reflective portion is greater than a reflectivity of the first optical reflective portion; the first contact layer is disposed between the substrate and the first optical reflective portion; the second contact layer is stacked on one side of the second optical reflective portion relative to the active light-emitting layer along the thickness direction; the first metal layer is electrically connected to the first contact layer; and the second metal layer is electrically connected to the second contact layer. A light-emitting side of the semiconductor light-emitting element is located on a side of the substrate away from the first optical reflective portion; the active light-emitting layer, the first optical reflective portion, the second optical reflective portion, the first contact layer and the second contact layer are stacked one on another along the thickness direction to form a columnar structure, the columnar structure defines a central axis, the semiconductor light-emitting element further includes an insulating layer at least partially covering the outer surface of the columnar structure, the insulating layer surrounds an embedding groove open along the thickness direction, a connecting portion of the second metal layer is embedded in the embedding groove and connected to the second contact layer; the second optical reflective portion further includes a metal diffusion layer, the metal diffusion layer is located on a side of the second contact layer and at least one of the plurality of pairs of distributed Bragg reflectors adjacent to the second metal layer, and the metal diffusion layer extends and diffuses toward a side away from the second metal layer.

[0008] As a preferred embodiment of the above technical solution, preferably, the connecting portion has a hollow annular cross-section, and the shape of the embedding groove corresponds to the shape of the connecting portion.

[0009] As a preferred embodiment of the above technical solution, preferably, viewed along the thickness direction, an inner contour of the connecting portion is the same shape as an outer contour of the connecting portion; the columnar structure is a cylinder, and the connecting portion is ring-shaped; viewed along the thickness direction, a radial dimension of an end face of the insulating layer facing the second metal layer is between 20 microns and 60 microns, and a radial dimension of the inner contour is between 2 microns and 15 microns.

[0010] As a preferred embodiment of the above technical solution, preferably, the insulating layer at least partially extends between the second metal layer and the second contact layer.

[0011] As a preferred embodiment of the above technical solution, preferably, viewed along the thickness direction, the extending areas of the embedding groove and the insulating layer at an end surface of the columnar structure provided with the second metal layer are not less than 10% of the area of ​​the end surface.

[0012] As a preferred embodiment of the above technical solution, preferably, a bonding layer is further provided between the insulating layer and one of the second contact layer and the second metal layer, and the bonding layer is made of a material containing at least one of titanium and zinc.

[0013] As a preferred embodiment of the above technical solution, preferably, the number of the plurality of pairs of distributed Bragg reflectors located in the large-diameter section is greater than the number of the plurality of pairs of distributed Bragg reflectors located in the small-diameter section.

[0014] As a preferred embodiment of the above technical solution, preferably, the outer contour shape of the metal diffusion layer corresponds to the shape of the connecting portion at least in part; a metal element of the metal diffusion layer includes at least one of zinc, beryllium, germanium and tin

[0015] As a preferred embodiment of the above technical solution, preferably, the metal diffusion layer extends hollow around the central axis, and a diffusion depth of the metal diffusion layer in the thickness direction is between 0.3 microns and 3 microns. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a side view schematic diagram of a first preferred embodiment of the present invention.

[0018] Figure 2 It is a schematic top view of the first preferred embodiment of the present invention.

[0019] Figure 3 It is a simulated diagram of reflectivity on each reflection path when the DBR logarithm is different in the first preferred embodiment of the present invention.

[0020] Figure 4 FIG. 1 is a schematic top view of a second preferred embodiment of the present invention.

[0021] Figure 5 It is a schematic top view of a third preferred embodiment of the present invention.

[0022] Figure 6 It is a side view schematic diagram of a fourth preferred embodiment of the present invention.

[0023] Figure 7 It is a schematic top view of the fourth preferred embodiment of the present invention.

[0024] Figure 8 It is a simulated diagram of reflectivity on each reflection path when the DBR logarithm is different in the fourth preferred embodiment of the present invention.

[0025] Fig. 9 It is a side view schematic diagram of a fifth preferred embodiment of the present invention.

[0026] Fig.10 It is a simulated diagram of reflectivity on each reflection path when the DBR logarithm is different in the fifth preferred embodiment of the present invention.

[0027] Fig.11 It is a side view schematic diagram of a sixth preferred embodiment of the present invention.

[0028] Fig.12 It is a schematic top view of the sixth preferred embodiment of the present invention.

[0029] Fig.13 It is a simulated diagram of reflectivity on each reflection path when the DBR logarithm is different in the sixth preferred embodiment of the present invention.

[0030] Fig.14 It is a side view schematic diagram of a seventh preferred embodiment of the present invention.

[0031] Wherein, 1: semiconductor light emitting element; 10: substrate; 11: anti-reflection optical film; 20: first optical reflector; 21, 44: distributed Bragg reflector; 30: active light emitting layer; 40, 40a, 40b: second optical reflector; 41, 41a, 41b, 41c: metal diffusion layer; 411a: rectangular hollow part; 411b: elliptical hollow part; 42, 42a: large diameter section; 43, 43a: small diameter section; 50: first contact layer; 60, 60a, 60b: second contact layer; 70: first metal diffusion layer; Metal layer; 80,80a,80b,80c: second metal layer; 81,81a,81b,81c: connecting part; 811: inner contour; 812: outer contour; 90,90a,90b,90c: insulating layer; 91,91a: embedded groove; 100: current limiting structure; 110: current channel; 200: bonding layer; C: central axis; E: light output side; P: columnar structure; R1,R1a,R1b,R1c: first reflection path; R2,R2a,R2b,R2c: second reflection path; V: thickness direction. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The following are only examples to illustrate possible implementations of the present invention, but are not intended to limit the scope of the present invention. The "one" or "at least one" preceding the nouns mentioned in the text does not limit the quantity, and it can also be "plural" according to needs. This change in quantity is also within the scope of the protection, which is stated in advance.

[0034] Please refer to Figures 1 to 3 , which shows the first preferred embodiment of the present invention, the semiconductor light emitting element 1 of the present invention includes a substrate 10, a first optical reflective portion 20, an active light emitting layer 30, a second optical reflective portion 40, a first contact layer 50, a second contact layer 60, a first metal layer 70 and a second metal layer 80.

[0035] The substrate 10 defines a thickness direction V; the first optical reflective portion 20 is stacked on one side of the substrate 10 along the thickness direction V and includes a plurality of pairs of distributed Bragg reflectors 21; the active light-emitting layer 30 is stacked on one side of the first optical reflective portion 20 opposite to the substrate 10; the second optical reflective portion 40 is stacked on one side of the active light-emitting layer 30 opposite to the first optical reflective portion 20 along the thickness direction V, the second optical reflective portion 40 includes a plurality of pairs of distributed Bragg reflectors 44, and a reflectivity of the second optical reflective portion 40 is greater than a reflectivity of the first optical reflective portion 20; the first contact layer 50 is disposed between the substrate 10 and the first optical reflective portion 20; the second contact layer 60 is stacked on the second optical reflective portion 40 opposite to the active light-emitting layer along the thickness direction V 30; the first metal layer 70 is electrically connected to the first contact layer 50; the second metal layer 80 is electrically connected to the second contact layer 60; a light emitting side E of the semiconductor light emitting element 1 is located on a side of the substrate 10 away from the first optical reflective portion 20; the active light emitting layer 30, the first optical reflective portion 20, the second optical reflective portion 40, the first contact layer 50 and the second contact layer 60 are mutually stacked along the thickness direction V to form a columnar structure P, the columnar structure P defines a central axis C, the semiconductor light emitting element 1 further includes an insulating layer 90 at least partially covering the outer surface of the columnar structure P, the insulating layer 90 surrounds an embedding groove 91 open along the thickness direction V, a connecting portion 81 of the second metal layer 80 is embedded in the embedding groove 91 and connected to the second contact layer 60. Thus, the semiconductor light emitting element 1 is a back-emitting light emitting element, and the columnar structure P can provide different reflectivities to achieve the effect of reducing the mode or stabilizing the polarization direction.

[0036] Specifically, the second optical reflective portion 40 further includes a metal diffusion layer 41, and the metal diffusion layer 41 is located on a side of the second contact layer 60 and at least one of the plurality of pairs of distributed Bragg reflectors 44 that is adjacent to the second metal layer 80, and the metal diffusion layer 41 extends and diffuses toward a side away from the second metal layer 80. It should be particularly noted that the metal diffusion layer 41 is a plurality of metal particles diffused between the second contact layer 60 and at least one of the plurality of pairs of distributed Bragg reflectors 44 and the second metal layer 80 by a metal diffusion mechanism, thereby causing the light from the active light-emitting layer 30 to generate light scattering and absorption losses by the plurality of metal particles. The outer contour shape of the metal diffusion layer 41 corresponds at least partially to the shape of the connecting portion 81. In the present embodiment, the metal diffusion layer 41 extends in a hollow shape around the central axis C, such as Figure 2As shown, the metal diffusion layer 41 extends in a circular ring shape around the central axis C and has a diffusion depth in the thickness direction V between 0.3 microns and 3 microns. The inner diameter of the metal diffusion layer 41 is between 2 microns and 15 microns, whereby the resistance of the region of the second optical reflective portion 40 where the metal diffusion layer 41 is provided is reduced, and the current can be guided to flow close to the central axis C. Further, a metal element of the metal diffusion layer 41 includes at least one of zinc, beryllium, germanium and tin, and the distribution density of the metal element preferably decreases toward the side away from the second metal layer 80, so that the reflectivity of the region of the columnar structure P adjacent to the central axis C is higher than the reflectivity of the region relatively away from the central axis C. In other embodiments, the metal diffusion layer can also be designed as a rectangular hollow extension or an elliptical hollow extension as required; for example, when the metal diffusion layer 41a is a hollow rectangular extension, as shown in FIG. Figure 4 As shown, the long side of a rectangular hollow portion 411a surrounded by the metal diffusion layer 41a is between 2 microns and 15 microns, and the short side is between 2 microns and 10 microns; when the metal diffusion layer 41b is a hollow elliptical extension, as shown in FIG. Figure 5 As shown, the long side of an elliptical hollow portion 411b surrounded by the metal diffusion layer 41b is between 2 micrometers and 15 micrometers, and the short side is between 2 micrometers and 10 micrometers.

[0037] The semiconductor light emitting element 1 further includes a current limiting structure 100, and the current limiting structure 100 includes a current channel 110, and a channel center of the current channel 110 passes through the central axis C, thereby limiting at least part of the transmission path of the light, and also increasing the resonance effect, which is conducive to forming a single-mode light beam. In this embodiment, the columnar structure P is a cylinder, the current limiting structure 100 is a high-aluminum oxide layer, and the current channel 110 is an oxide hole with a diameter between 5 microns and 15 microns, whereby the high-aluminum oxide layer has a low refractive index, which can effectively limit the light and current to the current channel 110, which is conducive to forming a single-mode light beam and reducing thermal effects. In other embodiments, the current limiting structure can also be an ion distribution structure, which can also achieve the effect of limiting current.

[0038] In this embodiment, the embedding groove 91 is a circular groove whose center passes through the central axis C and corresponds to the current channel 110; viewed along the thickness direction V, the radial dimension of the end face of the insulating layer 90 facing the second metal layer 80 is between 20 microns and 60 microns, and the maximum radial dimension of the connecting portion 81 is not less than 1 / 2 of the radial dimension of the end face, providing a sufficient reflection area and a good photon resonance effect. Viewed along the thickness direction V, the extension area of ​​the embedding groove 91 and the insulating layer 90 at the end face of the columnar structure P where the second metal layer 80 is provided is not less than 10% of the area of ​​the end face, providing a sufficient reflection area and a good modulation effect.

[0039] A light is defined as a first reflection path R1 and a second reflection path R2 emitted from the active light emitting layer 30 along the thickness direction V to the side provided with the second metal layer 80 and reflected toward the light emitting side E. The first reflection path R1 is closer to the central axis C than the second reflection path R2. The reflectivity of the light on the first reflection path R1 is greater than the reflectivity on the second reflection path R2. By means of the material change and structural design of the second optical reflection part 40, the metal diffusion layer 41 and the insulating layer 90, the first and second reflection paths R1 and R2 can provide different light reflectivities, so that the resonance effect of the part of the semiconductor light emitting element 1 adjacent to the central axis C is better than that of the part relatively far from the central axis C, and the transmission direction of the light is close to the central axis C. The light emitted from the light emitting side E can have a more consistent mode, which can be used to improve the bandwidth or transmission distance of the laser used for optical communication, and can also be used to reduce the light divergence angle of the sensing laser.

[0040] In this embodiment, the first reflection path R1 is the path of the light emitted from the active light emitting layer 30 to the second metal layer 80 and reflected toward the light emitting side E; the second reflection path R2 is the path of the light emitted from the active light emitting layer 30 to the second metal layer 80 via the metal diffusion layer 41 and reflected toward the light emitting side E. Figure 3 It can be seen from the reflectivity simulation diagram that under the condition that the number of pairs of distributed Bragg reflectors 44 (DBR) is the same (taking 20 pairs as an example), due to the high reflectivity provided by the material characteristics of the second metal layer 80, the reflectivity of the light transmitted on the first reflection path R1 is 99.98%; due to the light scattering effect produced by the metal diffusion layer 41, the reflectivity of the light transmitted on the second reflection path R2 is 99.35%, which is lower than the first reflection path R1, so that the portion adjacent to the central axis C has a better resonance effect than the radial outer side of the columnar structure P, thereby effectively reducing the optical mode, being easy to configure and having good reliability.

[0041] Furthermore, the active light-emitting layer 30 may be made of at least one of the materials selected from the group consisting of gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), gallium indium arsenide (GaInAs), aluminum gallium indium arsenide (AlGaInAs), gallium indium phosphide (GaInP), or aluminum gallium indium phosphide (AlGaInP). The lattice constant mismatch between the material of the active light-emitting layer 30 and gallium arsenide is less than 3%. The active light-emitting layer 30 may be doped with p / n type or without active doping, and the doping concentration may be between 1.0×10 15 Up to 4.0×10 18The first optical reflector 20 and the second optical reflector 40 are respectively composed of high and low refractive index materials arranged in a periodic staggered manner. The first optical reflector 20 provides a reflectivity of more than 95% at the emission wavelength of the semiconductor light emitting element 1, and the second optical reflector 40 provides a reflectivity of more than 99% at the emission wavelength of the semiconductor light emitting element 1. The first optical reflector 20 and the second optical reflector 40 can be made of at least one of the materials including gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), gallium indium arsenide (GaInAs), aluminum gallium indium arsenide (AlGaInAs), gallium indium phosphide (GaInP), and aluminum gallium indium phosphide (AlGaInP). The lattice constant mismatch between the materials of the first optical reflector 20 and the second optical reflector 40 and gallium arsenide is less than 0.5%, and the doping can be p-type doping or n-type doping, and the doping concentration is between 2.0×10 17 Up to 2.0×10 19 The first contact layer 50 and the second contact layer 60 are used as contact metals to form an ohmic contact. The first contact layer 50 and the second contact layer 60 can be made of at least one of the materials selected from the group consisting of gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), gallium indium arsenide (GaInAs), aluminum gallium indium arsenide (AlGaInAs), gallium indium phosphide (GaInP), and aluminum gallium indium phosphide (AlGaInP). The lattice constant mismatch between the materials of the first contact layer 50 and the second contact layer 60 and gallium arsenide is less than 0.5%. The first contact layer 50 can be heavily doped with n-type doping, and the second contact layer 60 can be heavily doped with p-type / n-type doping. The doping concentrations of the first contact layer 50 and the second contact layer 60 are respectively between 3.0×10 18 Up to 2.0×10 20 between.

[0042] Furthermore, the columnar structure P is entirely disposed on the substrate 10, and an anti-reflection optical film 11 is disposed on a side of the substrate 10 relatively far from the columnar structure P, which is conducive to the emission of the light. In this embodiment, the wavelength of the light emitted from the light-emitting side E is between 900 nanometers and 1200 nanometers; the substrate 10 is a semi-insulating, n-type doped or p-type doped plate made of gallium arsenide, and the thickness of the substrate 10 is between 50 micrometers and 800 micrometers, which can be adjusted and selected according to needs.

[0043] Please also refer to Figures 6 to 8The fourth preferred embodiment shown in the figure mainly differs from the first embodiment in that: the connecting portion 81a has a hollow annular cross section, the shape of the embedding groove 91a corresponds to the shape of the connecting portion 81a; the metal diffusion layer 41 corresponds to the embedding groove 91a in the thickness direction V. The first reflection path R1a is the path of the light emitted from the active light-emitting layer 30 to the insulating layer 90a and reflected toward the light-emitting side E, and the second reflection path R2a is the path of the light emitted from the active light-emitting layer 30 through the metal diffusion layer 41 to the connecting portion 81a and reflected toward the light-emitting side E. The metal diffusion layer 41 can cause light scattering loss, thereby making the reflectivity of the light in the second reflection path R2a lower than the reflectivity of the first reflection path R1a. Further, the insulating layer 90a at least partially extends between the second metal layer 80a and the second contact layer 60, and a refractive index of the insulating layer 90a is between 1.5 and 2.0 (e.g., 1.8). In the thickness direction V, a thickness of the insulating layer 90a is between 250 nm and 300 nm (e.g., 272 nm), thereby forming a high reflection layer, thereby improving the reflectivity of the light on the first reflection path R1a. In the present embodiment, the insulating layer 90a is made of a material including at least one of silicon oxide, silicon nitride, aluminum oxide, titanium oxide, magnesium fluoride, tantalum oxide, and indium tin oxide, and the thickness of the insulating layer 90a extending between the second metal layer 80a and the second contact layer 60 is between 10 nm and 1000 nm. In other embodiments, the desired reflection effect can also be achieved by changing the material of the insulating layer and adjusting its thickness accordingly.

[0044] Mate Reference Figure 7 , viewed along the thickness direction V, the connecting portion 81a is annular, an inner contour 811 of the connecting portion 81a and an outer contour 812 of the connecting portion 81a are of the same shape and are concentric circles, and a radial dimension of the inner contour 811 is between 2 microns and 15 microns. However, the shapes of the inner contour and the outer contour may also be different, for example but not limited to, the outer contour may be circular, and the inner contour may be elliptical, rectangular, multi-deformed, or other shapes, so that the polarization direction of the light can be adjusted.

[0045] Mate Reference Figure 8 , under the condition of the same number of DBR pairs (taking 20 pairs as an example), due to the high reflectivity provided by the insulating layer 90a, the reflectivity (99.99%) of the light transmitted on the first reflection path R1a is the highest; due to the light loss caused by the aforementioned non-smooth surface, the reflectivity (99.35%) of the light transmitted on the second reflection path R2a is lower than that of the first reflection path R1a, thereby enabling the portion adjacent to the central axis C to have a better resonance effect than the radial outer side of the columnar structure P, which is helpful to form a single-mode light beam.

[0046] Please also refer to Figures 9 and 10 The fifth preferred embodiment shown in the figure is mainly different from the fourth embodiment described above in that the second optical reflective portion 40a includes a large diameter section 42 adjacent to the active light emitting layer 30 and a small diameter section 43 adjacent to the second contact layer 60a, and a radial dimension of the large diameter section 42 is larger than a radial dimension of the small diameter section 43. The metal diffusion layer 41c is formed on the outer peripheral side of the small diameter section 43 and the second contact layer 60a and on the side of the large diameter section 42 facing the second metal layer 80b. Preferably, the number of pairs of the plurality of distributed Bragg reflectors 44 located in the large diameter section 42 is greater than the number of pairs of the plurality of distributed Bragg reflectors 44 located in the small diameter section 43; for example, the large diameter section 42 includes 18 pairs of DBRs, and the small diameter section 43 includes 7 pairs of DBRs, thereby providing a reflection path with low reflectivity and a reflection path with high reflectivity at the radial outer side of the columnar structure P and the area adjacent to the central axis C, respectively, so that the light is concentrated and emitted from the area adjacent to the central axis C, which is also conducive to the formation of a single-mode light beam. In other embodiments, the number of DBR pairs in the large diameter section may also be less than the number of DBR pairs in the small diameter section, so as to increase the reflectivity difference when the light is transmitted radially inside and outside, thereby obtaining different use effects.

[0047] In this embodiment, viewed along the thickness direction V, the outer contour of the large diameter section 42 is the same as the outer contour of the small diameter section 43 and is a concentric circle; a radial dimension of the large diameter section 42 is between 20 microns and 60 microns, and a radial dimension of the small diameter section 43 is between 2 microns and 15 microns, and the configuration ratio can be adjusted according to demand. In other embodiments, the outer contour of the large diameter section and the outer contour of the small diameter section may also be different, for example but not limited to, the outer contour of the large diameter section may be circular, and the outer contour of the small diameter section may be elliptical, rectangular, multi-deformed, and other shapes, so that the polarization direction of the light can be adjusted.

[0048] The first reflection path R1b is a path for the light to be emitted from the active light emitting layer 30 to the insulating layer 90b and reflected toward the light emitting side E. The second reflection path R2b is a path for the light to be emitted from the active light emitting layer 30 to the side of the connecting portion 81b facing the large diameter section 42 and reflected toward the light emitting side E. Fig.10The reflectivity simulation diagram shows that due to the high reflectivity provided by the material properties of the insulating layer 90b and the fact that the light passes through 25 pairs of DBRs on the first reflection path R1b, the reflectivity of the light transmitted on the first reflection path R1b is 99.99%; when the light is transmitted on the second reflection path R2b, it only passes through 18 pairs of DBRs and passes through the metal diffusion layer 41c, so the reflectivity of the light on the second reflection path R2b is 99.24%, which is lower than that of the first reflection path R1b, thereby further weakening the light reflectivity of the radial outer side of the columnar structure P, and the structure is simple, easy to process and can be more accurately controlled.

[0049] Please also refer to Figures 11 to 13 The sixth preferred embodiment shown in the figure is mainly different from the fifth embodiment described above in that: the second optical reflective portion 40b is not provided with the metal diffusion layer, and the connecting portion 81c has a circular solid cross section, and the insulating layer 90c integrally covers the large diameter section 42a, the small diameter section 43a and the second contact layer 60b. In this embodiment, the large diameter section 42a includes 15 pairs of DBRs, and the small diameter section 43a includes 10 pairs of DBRs; the first reflection path R1c is the path of the light emitted from the active light-emitting layer 30 to the side of the connecting portion 81c facing the second contact layer 60b and reflected toward the light-emitting side E, and the second reflection path R2c is the path of the light emitted from the active light-emitting layer 30 to the side of the insulating layer 90c facing the large diameter section 42a and reflected toward the light-emitting side E. Thus, due to the high reflectivity of the material properties of the second metal layer 80c and the fact that the light passes through 25 pairs of DBRs on the first reflection path R1c, the reflectivity of the light transmitted on the first reflection path R1c is 99.98%; when the light is transmitted on the second reflection path R2c, it only passes through 15 pairs of DBRs and can only reach a reflectivity of 99.29%, which is lower than the first reflection path R1c, and can also achieve a similar effect.

[0050] Please also refer to Fig.14 The seventh preferred embodiment shown is mainly different from the aforementioned fourth embodiment in that a bonding layer 200 is further provided between the second metal layer 80a and one of the insulating layer 90a and the second contact layer 60. The bonding layer 200 is made of, for example but not limited to, a material comprising at least one of titanium and zinc, so that the second metal layer 80a can be stably bonded to the insulating layer 90a and the second contact layer 60.

[0051] In summary, the semiconductor light-emitting element of the present invention can form reflection paths with different reflectivities by changing the material or thickness of the insulating layer, the number of DBRs, the structure of the connecting portion and the embedding groove, the distribution of the metal diffusion layer, etc., and provide a reflection path with low reflectivity and a reflection path with high reflectivity on the radial outer side of the columnar structure and the area adjacent to the central axis, respectively, so that the light has different resonance effects in different areas and the transmission direction of the light is close to the central axis, which is helpful to form a single-mode light beam and stabilize the polarization direction.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A semiconductor light emitting element, characterized in that: include: a substrate defining a thickness direction; a first optical reflective portion, stacked on one side of the substrate along the thickness direction, comprising a plurality of pairs of distributed Bragg reflectors; An active light-emitting layer, stacked on a side of the first optical reflective portion opposite to the substrate; a second optical reflective portion, stacked along the thickness direction on a side of the active light-emitting layer opposite to the first optical reflective portion, comprising a plurality of pairs of distributed Bragg reflectors, wherein a reflectivity of the second optical reflective portion is greater than a reflectivity of the first optical reflective portion; a first contact layer disposed between the substrate and the first optical reflective portion; A second contact layer is stacked on a side of the second optical reflective portion opposite to the active light-emitting layer along the thickness direction; a first metal layer electrically connected to the first contact layer; a second metal layer electrically connected to the second contact layer; wherein a light-emitting side of the semiconductor light-emitting element is located on a side of the substrate away from the first optical reflective portion; the active light-emitting layer, the first optical reflective portion, the second optical reflective portion, the first contact layer and the second contact layer are stacked one on another along the thickness direction to form a columnar structure, the columnar structure defines a central axis, the semiconductor light-emitting element further comprises an insulating layer at least partially covering the outer surface of the columnar structure, the insulating layer surrounds an embedding groove open along the thickness direction, a connecting portion of the second metal layer is embedded in the embedding groove and connected to the second contact layer; The second optical reflective portion further includes a large diameter segment adjacent to the active light-emitting layer and a small diameter segment adjacent to the second contact layer, and a radial dimension of the large diameter segment is greater than a radial dimension of the small diameter segment.

2. A semiconductor light emitting element, characterized in that: include: a substrate defining a thickness direction; a first optical reflective portion, stacked on one side of the substrate along the thickness direction, comprising a plurality of pairs of distributed Bragg reflectors; An active light-emitting layer, stacked on a side of the first optical reflective portion opposite to the substrate; a second optical reflective portion, stacked along the thickness direction on a side of the active light-emitting layer opposite to the first optical reflective portion, comprising a plurality of pairs of distributed Bragg reflectors, wherein a reflectivity of the second optical reflective portion is greater than a reflectivity of the first optical reflective portion; a first contact layer disposed between the substrate and the first optical reflective portion; A second contact layer is stacked on a side of the second optical reflective portion opposite to the active light-emitting layer along the thickness direction; a first metal layer electrically connected to the first contact layer; a second metal layer electrically connected to the second contact layer; wherein a light-emitting side of the semiconductor light-emitting element is located on a side of the substrate away from the first optical reflective portion; the active light-emitting layer, the first optical reflective portion, the second optical reflective portion, the first contact layer and the second contact layer are stacked one on another along the thickness direction to form a columnar structure, the columnar structure defines a central axis, the semiconductor light-emitting element further comprises an insulating layer at least partially covering the outer surface of the columnar structure, the insulating layer surrounds an embedding groove open along the thickness direction, a connecting portion of the second metal layer is embedded in the embedding groove and connected to the second contact layer; The second optical reflective portion further comprises a metal diffusion layer, which is located on a side of at least one of the second contact layer and the plurality of pairs of DBRs adjacent to the second metal layer, and extends and diffuses toward a side away from the second metal layer.

3. The semiconductor light emitting element according to claim 1 or 2, characterized in that: The connecting portion has a hollow annular cross section, and the shape of the embedding groove corresponds to the shape of the connecting portion.

4. The semiconductor light emitting element according to claim 3, characterized in that: Viewed along the thickness direction, an inner contour of the connecting portion has the same shape as an outer contour of the connecting portion; the columnar structure is a cylinder, and the connecting portion is in the shape of a circular ring; viewed along the thickness direction, a radial dimension of an end face of the insulating layer facing the second metal layer is between 20 microns and 60 microns, and a radial dimension of the inner contour is between 2 microns and 15 microns.

5. The semiconductor light emitting element according to claim 1 or 2, characterized in that: The insulating layer at least partially extends between the second metal layer and the second contact layer.

6. The semiconductor light emitting element according to claim 1 or 2, characterized in that: Viewed along the thickness direction, the extending areas of the embedding groove and the insulating layer at an end surface of the columnar structure provided with the second metal layer are not less than 10% of the area of ​​the end surface.

7. The semiconductor light emitting element according to claim 1 or 2, characterized in that: A bonding layer is further arranged between one of the insulating layer and the second contact layer and the second metal layer. The bonding layer is made of a material containing at least one of titanium and zinc.

8. The semiconductor light emitting element according to claim 1, wherein: The number of the plurality of pairs of distributed Bragg reflectors located in the large-diameter section is greater than the number of the plurality of pairs of distributed Bragg reflectors located in the small-diameter section.

9. The semiconductor light emitting element according to claim 2, characterized in that: The outer contour shape of the metal diffusion layer corresponds at least partially to the shape of the connecting portion; a metal element of the metal diffusion layer includes at least one of zinc, beryllium, germanium and tin.

10. The semiconductor light emitting element according to claim 2, characterized in that: The metal diffusion layer extends in a hollow shape around the central axis. A diffusion depth of the metal diffusion layer in the thickness direction is between 0.3 micrometers and 3 micrometers.

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