Semiconductor light-emitting structure and preparation method therefor

Abstract

A semiconductor light-emitting structure and a preparation method therefor, which can improve the quality of a light beam of the semiconductor light-emitting structure. The semiconductor light-emitting structure comprises: a semiconductor substrate layer (200), a first confinement layer (210), a first waveguide layer (220), an active layer (230), a second waveguide layer (240) and a second confinement layer (250) which are sequentially stacked, wherein the active layer (230) comprises a first superlattice active layer (231) and a second superlattice active layer (232) which are stacked, and the second superlattice active layer (232) is located on the side of the first superlattice active layer (231) that faces away from the first waveguide layer (220). The semiconductor light-emitting structure further comprises an insertion layer (260) which is located between the second superlattice active layer (232) and the first superlattice active layer (231), wherein a refractive index of the insertion layer (260) is less than an effective refractive index of the first superlattice active layer (231) and less than an effective refractive index of the second superlattice active layer (232).

Description

A semiconductor light-emitting structure and a method for preparing the same

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on March 8, 2024, with application number 202410263217.5 and invention name “A semiconductor light-emitting structure and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of semiconductor technology, and in particular to a semiconductor light-emitting structure and a method for preparing the same. Background Art

[0004] Semiconductor light-emitting structures use certain semiconductor materials as the working medium to produce stimulated emission. Their operating principle is to achieve population inversion of non-equilibrium carriers through specific excitation methods, generating stimulated emission. Semiconductor light-emitting structures are widely used due to their small size and high electro-optical conversion efficiency.

[0005] Quantum cascade lasers are an important light-emitting structure. The spectral range of quantum cascade lasers covers the mid-infrared to far-infrared bands. They can be used in a variety of fields such as trace gas detection and free-space optical communications, and have broad market application prospects. Mid-infrared quantum cascade lasers usually adopt a trench-buried ridge structure, etching the active area into a single ridge type, and using secondary epitaxial growth technology to fill Fe-doped InP on both sides. Fe-doped InP has good electrical insulation and thermal conductivity properties, while ensuring the device's heat dissipation capacity and optical confinement effect. After the wafer process is completed, the device will be cleaved and coated, and an anti-reflection film will be evaporated on the front cavity surface and an anti-reflection film will be evaporated on the back cavity surface to form a resonant cavity structure.

[0006] Currently, the existing semiconductor light-emitting structure has the problem of beam quality degradation. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present application is how to improve the light beam quality of a semiconductor light-emitting structure, thereby providing a semiconductor light-emitting structure and a preparation method thereof.

[0008] The present application provides a semiconductor light-emitting structure, comprising: a semiconductor substrate layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; the active layer comprising a first superlattice active layer and a second superlattice active layer stacked, the second superlattice active layer being located on a side of the first superlattice active layer facing away from the first waveguide layer; the semiconductor light-emitting structure further comprising: an insertion layer located between the second superlattice active layer and the first superlattice active layer, the refractive index of the insertion layer being less than the effective refractive index of the first superlattice active layer and less than the effective refractive index of the second superlattice active layer.

[0009] Optionally, the semiconductor light-emitting structure further includes: a first lattice matching layer located between the first superlattice active layer and the insertion layer, and a first transition layer located between the first lattice matching layer and the insertion layer, the first lattice matching layer and the first superlattice active layer are in contact with each other, and the conduction band energy level of the first transition layer is higher than the conduction band energy level of the first lattice matching layer and lower than the conduction band energy level of the insertion layer; and / or, the semiconductor light-emitting structure further includes: a second lattice matching layer located between the second superlattice active layer and the insertion layer, and a second transition layer located between the second lattice matching layer and the insertion layer, the second lattice matching layer and the second superlattice active layer are in contact with each other, and the conduction band energy level of the second transition layer is higher than the conduction band energy level of the second lattice matching layer and lower than the conduction band energy level of the insertion layer.

[0010] Optionally, the first transition layer includes multiple stacked first sub-transition layers; in the arrangement direction from the first superlattice active layer to the insertion layer, the conduction band energy levels of the multiple stacked first sub-transition layers increase layer by layer; or, the first transition layer is a single-layer structure, and the conduction band energy level of the first transition layer is constant in the thickness direction.

[0011] Optionally, the second transition layer includes a plurality of stacked second sub-transition layers; in the arrangement direction from the second superlattice active layer to the insertion layer, the conduction band energy levels of the plurality of stacked second sub-transition layers increase layer by layer; or, the second transition layer is a single-layer structure, and the conduction band energy level of the second transition layer is constant in the thickness direction.

[0012] Optionally, the semiconductor light-emitting structure further includes: a third lattice matching layer located between the first superlattice active layer and the first waveguide layer, and a third transition layer located between the third lattice matching layer and the first waveguide layer, the third lattice matching layer being in contact with the first superlattice active layer, and a conduction band energy level of the third transition layer being higher than a conduction band energy level of the third lattice matching layer and lower than a conduction band energy level of the first waveguide layer; and / or the semiconductor light-emitting structure further includes: a fourth lattice matching layer located between the second superlattice active layer and the second waveguide layer, and a fourth transition layer located between the fourth lattice matching layer and the second waveguide layer, the fourth lattice matching layer being in contact with the second superlattice active layer, and a conduction band energy level of the fourth transition layer being higher than a conduction band energy level of the fourth lattice matching layer and lower than a conduction band energy level of the second waveguide layer.

[0013] Optionally, the third transition layer includes multiple stacked third sub-transition layers; in the arrangement direction from the first waveguide layer to the first superlattice active layer, the conduction band energy levels of the multiple stacked third sub-transition layers decrease layer by layer; or, the third transition layer is a single-layer structure, and the conduction band energy level of the third transition layer is constant in the thickness direction.

[0014] Optionally, the fourth transition layer includes multiple stacked fourth sub-transition layers; in the arrangement direction from the second waveguide layer to the second superlattice active layer, the conduction band energy levels of the multiple stacked fourth sub-transition layers decrease layer by layer; or, the fourth transition layer is a single-layer structure, and the conduction band energy level of the fourth transition layer is constant in the thickness direction.

[0015] Optionally, the insertion layer is an InP insertion layer doped with conductive ions or undoped with conductive ions, or the insertion layer is an InAlAs insertion layer doped with conductive ions or undoped with conductive ions, or the insertion layer is an InGaAlAs insertion layer doped with conductive ions or undoped with conductive ions.

[0016] Optionally, the thickness of the insertion layer is 0.6 μm to 1.2 μm.

[0017] Optionally, the first superlattice active layer includes multiple layers of first barrier layers and multiple layers of first quantum well layers, the first barrier layers and the first quantum well layers are alternately stacked, the top and bottom layers of the first superlattice active layer are both first barrier layers, and the conduction band energy level of the first quantum well layer is lower than the conduction band energy level of the first barrier layer; the second superlattice active layer includes multiple layers of second barrier layers and multiple layers of second quantum well layers, the second barrier layers and the second quantum well layers are alternately stacked, the top and bottom layers of the second superlattice active layer are both second barrier layers, and the conduction band energy level of the second quantum well layer is lower than the conduction band energy level of the second barrier layer; the conduction band energy level of the inserted layer is higher than the conduction band energy level of the first quantum well layer and lower than the conduction band energy level of the first barrier layer, and the conduction band energy level of the inserted layer is higher than the conduction band energy level of the second quantum well layer and lower than the conduction band energy level of the second barrier layer.

[0018] Optionally, the thickness of the first superlattice active layer is 0.8 μm to 1.0 μm; and the thickness of the second superlattice active layer is 0.8 μm to 1.0 μm.

[0019] Optionally, the width of the active layer is 8 μm to 10 μm.

[0020] Optionally, the first superlattice active layer includes a first sub-superlattice region and a second sub-superlattice region, the second sub-superlattice region is located on a side surface of the first sub-superlattice region away from the first waveguide layer, and the doping concentration of conductive ions in the second sub-superlattice region is greater than the doping concentration of conductive ions in the first sub-superlattice region; and / or, the second superlattice active layer includes a third sub-superlattice region and a fourth sub-superlattice region, the fourth sub-superlattice region is located on a side surface of the third sub-superlattice region away from the insertion layer, and the doping concentration of conductive ions in the third sub-superlattice region is greater than the doping concentration of conductive ions in the fourth sub-superlattice region.

[0021] Optionally, the doping concentration of conductive ions in the third sub-superlattice region is 20% to 50% higher than the doping concentration of conductive ions in the fourth sub-superlattice region; and / or the doping concentration of conductive ions in the second sub-superlattice region is 20% to 50% higher than the doping concentration of conductive ions in the first sub-superlattice region.

[0022] Optionally, an intermediate plane between a side surface of the first superlattice active layer facing away from the second superlattice active layer and a side surface of the second superlattice active layer facing away from the first superlattice active layer is located in the insertion layer; a distance from a side surface of the first superlattice active layer facing away from the second superlattice active layer to the intermediate plane is equal to a distance from a side surface of the second superlattice active layer facing away from the first superlattice active layer to the intermediate plane.

[0023] The present application also provides a method for preparing a semiconductor light-emitting structure, comprising: providing a semiconductor substrate layer; sequentially forming a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer on the semiconductor substrate layer; the step of forming the active layer comprises: sequentially stacking a first superlattice active layer and a second superlattice active layer; the method for preparing the semiconductor light-emitting structure further comprises: before forming the second superlattice active layer, forming an insertion layer on a side of the first superlattice active layer facing away from the first waveguide layer; the refractive index of the insertion layer is less than the effective refractive index of the first superlattice active layer and less than the effective refractive index of the second superlattice active layer.

[0024] Optionally, the method further includes: before forming the insertion layer, forming a first lattice matching layer on a surface of the first superlattice active layer facing away from the first waveguide layer; forming a first transition layer on a side of the first lattice matching layer facing away from the first waveguide layer; the conduction band energy level of the first transition layer is higher than the conduction band energy level of the first lattice matching layer and lower than the conduction band energy level of the insertion layer; the step of forming the insertion layer comprises: forming the insertion layer on a surface of the first transition layer facing away from the first waveguide layer; and / or further includes: before forming the second superlattice active layer, forming a second transition layer on a side of the insertion layer facing away from the first superlattice active layer; forming a second lattice matching layer on a side of the second transition layer facing away from the first superlattice active layer; the conduction band energy level of the second transition layer is higher than the conduction band energy level of the second lattice matching layer and lower than the conduction band energy level of the insertion layer; the step of forming the second superlattice active layer comprises: forming the second superlattice active layer on a surface of the second lattice matching layer facing away from the first superlattice active layer.

[0025] Optionally, the step of forming a first transition layer on a side of the first lattice matching layer facing away from the first waveguide layer includes forming a plurality of stacked first sub-transition layers; and in an arrangement direction from the first superlattice active layer to the insertion layer, the conduction band energy levels of the plurality of stacked first sub-transition layers increase layer by layer.

[0026] Optionally, the step of forming a second transition layer on the side of the insertion layer away from the first superlattice active layer includes: forming a plurality of stacked second sub-transition layers; and in the arrangement direction from the second superlattice active layer to the insertion layer, the conduction band energy levels of the plurality of stacked second sub-transition layers increase layer by layer.

[0027] Optionally, the method further includes: before forming the first superlattice active layer, forming a third transition layer on a side of the first waveguide layer facing away from the first confinement layer; forming a third lattice matching layer on a side of the third transition layer facing away from the first confinement layer; the conduction band energy level of the third transition layer being higher than the conduction band energy level of the third lattice matching layer and lower than the conduction band energy level of the first waveguide layer; the step of forming the first superlattice active layer comprises: forming the first superlattice active layer on a surface of the third lattice matching layer facing away from the first confinement layer; and / or further includes: before forming the second waveguide layer, forming a fourth lattice matching layer on a surface of the second superlattice active layer facing away from the first superlattice active layer; forming a fourth transition layer on a side of the fourth lattice matching layer facing away from the first superlattice active layer, the conduction band energy level of the fourth transition layer being higher than the conduction band energy level of the fourth lattice matching layer and lower than the conduction band energy level of the second waveguide layer; and the step of forming the second waveguide layer comprises: forming a second waveguide layer on a side of the fourth transition layer facing away from the first superlattice active layer.

[0028] Optionally, the step of forming a third transition layer on the side of the first waveguide layer facing away from the first confinement layer includes: forming a plurality of stacked third sub-transition layers, wherein the conduction band energy levels of the plurality of stacked third sub-transition layers decrease layer by layer in an arrangement direction from the first waveguide layer to the first superlattice active layer.

[0029] Optionally, the step of forming a fourth transition layer on the side of the fourth lattice matching layer facing away from the first superlattice active layer includes: forming a plurality of stacked fourth sub-transition layers, wherein the conduction band energy levels of the plurality of stacked fourth sub-transition layers decrease layer by layer in an arrangement direction from the second waveguide layer to the second superlattice active layer.

[0030] Optionally, the step of forming the first superlattice active layer includes: sequentially forming a first sub-superlattice region and a second sub-superlattice region stacked together, the second sub-superlattice region being located on a side surface of the first sub-superlattice region away from the first waveguide layer, and the doping concentration of conductive ions in the second sub-superlattice region being greater than the doping concentration of conductive ions in the first sub-superlattice region; and / or, the step of forming the second superlattice active layer includes: sequentially forming a third sub-superlattice region and a fourth sub-superlattice region stacked together, the fourth sub-superlattice region being located on a side surface of the third sub-superlattice region away from the insertion layer, and the doping concentration of conductive ions in the third sub-superlattice region being greater than the doping concentration of conductive ions in the fourth sub-superlattice region.

[0031] The technical solution of this application has the following beneficial effects:

[0032] The semiconductor light-emitting structure provided by the technical solution of the present application has an insertion layer arranged so that a single active layer is divided into a first superlattice active layer and a second superlattice active layer separated by a gap. The insertion layer does not contribute to the gain value. Since the refractive index of the insertion layer is less than the effective refractive index of the first superlattice active layer and less than the effective refractive index of the second superlattice active layer, the insertion layer is used to reduce the optical confinement factor of the transverse mode. Specifically, the insertion layer reduces the optical confinement factor of the high-order mode to a greater extent than the optical confinement factor of the fundamental mode. The insertion layer increases the difference between the optical confinement factor of the fundamental mode and the optical confinement factor of the high-order mode, thereby increasing the difference in threshold gain between the high-order mode and the fundamental mode. Therefore, the high-order mode is effectively suppressed, so that the semiconductor light-emitting structure operates stably and the beam quality of the semiconductor light-emitting structure is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] FIG1 is a schematic diagram of a semiconductor light-emitting structure in the related art;

[0035] FIG2 is a schematic diagram of a semiconductor light emitting structure in an embodiment of the present application;

[0036] FIG3 is a schematic diagram of a semiconductor light emitting structure in another embodiment of the present application. DETAILED DESCRIPTION

[0037] A semiconductor light-emitting structure, referring to FIG1 , includes: a substrate layer 100; a lower confinement layer 110, a lower waveguide layer 120, an active layer 130, an upper waveguide layer 140, and an upper confinement layer 150 located on the substrate layer 100; and an insulating epitaxial layer 180 located on the sidewalls of the lower waveguide layer 120, the active layer 130, the upper waveguide layer 140, and the upper confinement layer 150.

[0038] The aforementioned semiconductor light-emitting structure suffers from beam quality degradation. Research has discovered that the reason for this is that, in addition to the fundamental mode, the light field modes present in the active layer 130 also include higher-order modes such as the first-order mode and the second-order mode. On the light-emitting surface of the semiconductor light-emitting structure, the fundamental mode light field has a single spot; on the light-emitting surface of the semiconductor light-emitting structure, the first-order mode light field has two small spots distributed across the width of the semiconductor light-emitting structure; and on the light-emitting surface of the second-order mode light field has three small spots distributed across the width of the semiconductor light-emitting structure. The lower waveguide layer 120, active layer 130, upper waveguide layer 140, and upper confinement layer 150 form a ridge structure. This ridge structure reduces optical absorption and scattering on the sidewalls of the active layer 130. As a result, the fundamental mode, first-order mode, and second-order mode have similar optical loss values, allowing the fundamental mode, first-order mode, and second-order mode to coexist in the active layer 130. When the semiconductor light-emitting structure is working, three lateral light field modes can appear at the same time, accompanied by a certain phenomenon of light field mode switching, causing the light wave field of the semiconductor light-emitting structure to exhibit a mode instability. Parameters such as the far-field divergence angle and the lasing wavelength will gradually drift with the increase of current, eventually leading to the degradation of the beam quality of the semiconductor light-emitting structure.

[0039] The simplest way to suppress higher-order modes is to reduce the ridge width of the active layer 130. Taking the active layer 130 of a medium-wavelength 4.6-micron device as an example, when the ridge width of the active layer 130 is reduced to below 7 μm, theoretically, the optical confinement factor of the higher-order modes is significantly reduced compared to the fundamental transverse mode, effectively suppressing the emergence of higher-order modes.

[0040] However, there are many limitations to suppressing higher-order modes by reducing the ridge width of the active layer 130: (1) When the ridge width of the active layer 130 is reduced, the gain volume of the active layer 130 decreases, resulting in a decrease in optical output power; (2) when the device is operating, a large amount of carriers are injected into the active layer 130, causing a change in the refractive index; at the same time, the temperature of the active layer 130 rises sharply during operation, also causing a change in the refractive index of the active layer 130. These two effects ultimately lead to a change in the optical confinement of the active layer 130, weakening the suppression of higher-order modes, causing higher-order modes to reappear and resulting in a decrease in beam quality.

[0041] On this basis, the present application provides a semiconductor light-emitting structure and a preparation method thereof to avoid degradation of beam quality.

[0042] The following will clearly and completely describe the technical solution of this application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0043] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0045] Example 1

[0046] An embodiment of the present application provides a semiconductor light-emitting structure. Referring to FIG2 , the structure includes: a semiconductor substrate layer 200, a first confinement layer 210, a first waveguide layer 220, an active layer 230, a second waveguide layer 240, and a second confinement layer 250, stacked in sequence. The active layer 230 includes a first superlattice active layer 231 and a second superlattice active layer 232, wherein the second superlattice active layer 232 is located on a side of the first superlattice active layer 231 facing away from the first waveguide layer 220. The semiconductor light-emitting structure further includes an insertion layer 260 located between the second superlattice active layer 232 and the first superlattice active layer 231. The refractive index of the insertion layer 260 is lower than the effective refractive index of the first superlattice active layer 231 and lower than the effective refractive index of the second superlattice active layer 232.

[0047] In this embodiment, the provision of the insertion layer 260 separates the single active layer 230 into a first superlattice active layer 231 and a second superlattice active layer 232. The insertion layer 260 does not contribute to the gain value. Because the refractive index of the insertion layer 260 is less than the effective refractive index of the first superlattice active layer 231 and less than the effective refractive index of the second superlattice active layer 232, the insertion layer 260 is used to reduce the optical confinement factor of the transverse mode. Specifically, the insertion layer 260 reduces the optical confinement factor of the high-order mode to a greater extent than that of the fundamental mode. The insertion layer 260 increases the difference between the optical confinement factor of the fundamental mode and the optical confinement factor of the high-order mode, thereby increasing the difference in threshold gain between the high-order mode and the fundamental mode. Therefore, the high-order mode is effectively suppressed, enabling stable operation of the semiconductor light-emitting structure and improving the beam quality of the semiconductor light-emitting structure.

[0048] The order of the higher-order mode is greater than that of the fundamental mode. The higher-order mode includes the first-order mode, the second-order mode, and modes with higher orders than the second-order mode.

[0049] The effective refractive index of the first superlattice active layer 231 refers to the average refractive index of the first superlattice active layer 231 as a whole. The effective refractive index of the second superlattice active layer 232 refers to the average refractive index of the second superlattice active layer 232 as a whole.

[0050] In this embodiment, the semiconductor light emitting structure is described by taking an edge emitting semiconductor laser as an example, such as a quantum cascade edge emitting semiconductor laser, which includes a mid-infrared quantum cascade edge emitting semiconductor laser.

[0051] In this embodiment, the semiconductor substrate layer 200 is an InP substrate layer. It should be noted that in other embodiments, the semiconductor substrate layer 200 may also be made of other materials.

[0052] In one embodiment, the material of the first confinement layer 210 is InP doped with conductive ions. Based on the characteristics of mid-infrared quantum cascade edge-emitting semiconductor lasers, the first confinement layer 210 can only be made of InP doped with conductive ions.

[0053] In one embodiment, the thickness of the first confinement layer 210 is 2 micrometers to 4 micrometers, for example, 2 micrometers.

[0054] In one embodiment, the doping concentration of the conductive ions in the first confinement layer 210 is 0.5×10 17 atom / cm 3 ~5×10 17 atom / cm 3 , for example 2×10 17 atom / cm 3 .

[0055] In one embodiment, the material of the first waveguide layer 220 is InP doped with conductive ions, and the doping concentration of the conductive ions in the first waveguide layer 220 is lower than the doping concentration of the conductive ions in the first confinement layer 210 .

[0056] In one embodiment, the doping concentration of the conductive ions in the first waveguide layer 220 is 1.0×10 16 atom / cm 3 ~5.0×10 16 atom / cm 3 , for example 2×10 16 atom / cm 3 .

[0057] In one embodiment, the thickness of the first waveguide layer 220 is 1 micrometer to 3 micrometers, for example, 2 micrometers.

[0058] In one embodiment, the material of the second confinement layer 250 is InP doped with conductive ions.

[0059] In one embodiment, the thickness of the second confinement layer 250 is 1 micrometer to 3 micrometers, for example, 2 micrometers.

[0060] In one embodiment, the material of the second waveguide layer 240 is InP doped with conductive ions, and the doping concentration of the conductive ions in the second waveguide layer 240 is lower than the doping concentration of the conductive ions in the second confinement layer 250 .

[0061] In one embodiment, the doping concentration of the conductive ions in the second waveguide layer 240 is 1.0×10 16 atom / cm 3 ~5.0×10 16 atom / cm 3 , for example 2×10 16 atom / cm 3 .

[0062] In one embodiment, the thickness of the second waveguide layer 240 is 1 micrometer to 3 micrometers, for example, 2 micrometers.

[0063] The conductive ions in the first waveguide layer 220, the conductive ions in the first confinement layer 210, the conductive ions in the second waveguide layer 240, and the conductive ions in the second confinement layer 250 are of the same conductivity type. For example, the conductive ions in the first waveguide layer 220, the conductive ions in the first confinement layer 210, the conductive ions in the second waveguide layer 240, and the conductive ions in the second confinement layer 250 are of n-type conductivity, and the n-type conductive ions include Si ions.

[0064] The first superlattice active layer 231 has a superlattice structure. The first superlattice active layer 231 includes multiple first barrier layers and multiple first quantum well layers. The first barrier layers and first quantum well layers are alternately stacked, with the top and bottom layers of the first superlattice active layer 231 both being first barrier layers. The band gap width of the first quantum well layer is smaller than the band gap width of the first barrier layer. The conduction band energy level of the first quantum well layer is lower than the conduction band energy level of the first barrier layer.

[0065] The second superlattice active layer 232 has a superlattice structure. It includes multiple second barrier layers and multiple second quantum well layers. The second barrier layers and second quantum well layers are alternately stacked, with the top and bottom layers of the second superlattice active layer 232 both being second barrier layers. The band gap width of the second quantum well layer is smaller than the band gap width of the second barrier layer. The conduction band energy level of the second quantum well layer is lower than that of the second barrier layer.

[0066] In one embodiment, the materials of the first quantum well layer and the second quantum well layer include InxGa (1-x) As, the materials of the first barrier layer and the second barrier layer include InyAl (1-y) As.

[0067] The first superlattice active layer 231 may be doped with conductive ions or undoped with conductive ions. The second superlattice active layer 232 may be doped with conductive ions or undoped with conductive ions. When the first superlattice active layer 231 is doped with conductive ions, the conductive ions in the first superlattice active layer 231 have the same conductivity type as the conductive ions in the first confinement layer 210, the first waveguide layer 220, the second waveguide layer 240, and the second confinement layer 250. When the second superlattice active layer 232 is doped with conductive ions, the conductive ions in the second superlattice active layer 232 have the same conductivity type as the conductive ions in the first confinement layer 210, the first waveguide layer 220, the second waveguide layer 240, and the second confinement layer 250. For example, the conductive ions in the first superlattice active layer 231 have an n-type conductivity, and the conductive ions in the second superlattice active layer 232 have an n-type conductivity. Specifically, in one embodiment, the conductive ions in the first superlattice active layer 231 and the second superlattice active layer 232 are, for example, Si ions.

[0068] In one embodiment, the doping concentration of the conductive ions in the first superlattice active layer 231 is constant in the thickness direction. The doping concentration of the conductive ions in the second superlattice active layer 232 is constant in the thickness direction.

[0069] In one embodiment, the thickness of the first superlattice active layer 231 is 0.8 μm to 1.0 μm, and the thickness of the second superlattice active layer 232 is 0.8 μm to 1.0 μm.

[0070] The first barrier layer has a relatively small thickness, which enables the first barrier layer to have a tunneling effect. The second barrier layer has a relatively small thickness, which enables the second barrier layer to have a tunneling effect. In one embodiment, the first barrier layer has a thickness of 1 nm to 3 nm. In one embodiment, the second barrier layer has a thickness of 1 nm to 3 nm.

[0071] In one embodiment, the width of the active layer 230 is 8 μm to 10 μm. The wider width of the active layer 230 increases the light output power.

[0072] In one embodiment, the insertion layer 260 is an InP insertion layer doped with conductive ions or undoped with conductive ions, or the insertion layer 260 is an InAlAs insertion layer doped with conductive ions or undoped with conductive ions, or the insertion layer 260 is an InGaAlAs insertion layer doped with conductive ions or undoped with conductive ions.

[0073] In one embodiment, the conductive ions in the insertion layer 260 have the same conductivity type as the conductive ions in the first confinement layer 210, the first waveguide layer 220, the second waveguide layer 240, and the second confinement layer 250. In one embodiment, the conductive ions in the insertion layer 260 are n-type, for example, the conductive ions are Si ions.

[0074] In one embodiment, the doping concentration of the conductive ions in the insertion layer 260 is 1.0×10 16 atom / cm 3 ~5.0×10 16 atom / cm 3 , for example 2×10 16 atom / cm 3 .

[0075] In one embodiment, the band gap width of the insertion layer 260 is greater than the band gap width of the second quantum well layer and less than the band gap width of the second barrier layer, and the band gap width of the insertion layer 260 is greater than the band gap width of the first quantum well layer and less than the band gap width of the first barrier layer. The conduction band energy level of the insertion layer 260 is higher than the conduction band energy level of the first quantum well layer and lower than the conduction band energy level of the first barrier layer. The conduction band energy level of the insertion layer 260 is higher than the conduction band energy level of the second quantum well layer and lower than the conduction band energy level of the second barrier layer.

[0076] In one embodiment, the thickness of the insertion layer 260 is 0.6 μm to 1.2 μm.

[0077] In one embodiment, the relationship between the thickness of the insertion layer 260 and the emission wavelength of the semiconductor light emitting structure is: the thickness of the insertion layer 260 is between 15% and 50% of the emission wavelength.

[0078] The thickness of the insertion layer 260 is in a relationship with the thickness of the first superlattice active layer 231: the thickness of the insertion layer 260 is between 50% and 150% of the thickness of the first superlattice active layer 231. The thickness of the insertion layer 260 is in a relationship with the thickness of the second superlattice active layer 232: the thickness of the insertion layer 260 is between 50% and 150% of the thickness of the second superlattice active layer 232. The thickness of the insertion layer 260 is set so that the insertion layer 260 contributes to the loss of the high-order modes.

[0079] An intermediate plane between a surface of the first superlattice active layer 231 facing away from the second superlattice active layer 232 and a surface of the second superlattice active layer 232 facing away from the first superlattice active layer 231 is located in the insertion layer 260. The distance between the surface of the first superlattice active layer 231 facing away from the second superlattice active layer 232 and the intermediate plane is equal to the distance between the surface of the second superlattice active layer 232 facing away from the first superlattice active layer 231 and the intermediate plane.

[0080] In one embodiment, the semiconductor light-emitting structure further includes: a first lattice matching layer 281 located between the first superlattice active layer 231 and the insertion layer 260, and a first transition layer 271 located between the first lattice matching layer 281 and the insertion layer 260, wherein the first lattice matching layer 281 is in contact with the first superlattice active layer 231, and a conduction band energy level of the first transition layer 271 is higher than the conduction band energy level of the first lattice matching layer 281 and lower than the conduction band energy level of the insertion layer 260; and the semiconductor light-emitting structure further includes: a second lattice matching layer 282 located between the second superlattice active layer 232 and the insertion layer 260, and a second transition layer 272 located between the second lattice matching layer 282 and the insertion layer 260, wherein the second lattice matching layer 282 is in contact with the second superlattice active layer 232, and a conduction band energy level of the second transition layer 272 is higher than the conduction band energy level of the second lattice matching layer 282 and lower than the conduction band energy level of the insertion layer 260.

[0081] The bandgap width of the first transition layer 271 is larger than the bandgap width of the first lattice matching layer 281 and smaller than the bandgap width of the insertion layer 260. The bandgap width of the second transition layer 272 is larger than the bandgap width of the second lattice matching layer 282 and smaller than the bandgap width of the insertion layer 260.

[0082] In other embodiments, the semiconductor light emitting structure further includes: a first lattice matching layer and a first transition layer; or the semiconductor light emitting structure further includes: a second lattice matching layer and a second transition layer.

[0083] In other embodiments, the first lattice matching layer, the first transition layer, the second lattice matching layer, and the second transition layer may not be provided.

[0084] In other embodiments, the first and second lattice matching layers are provided, but the first and second transition layers are not provided. In other embodiments, either the first or second lattice matching layer is provided. In other embodiments, neither the first or second lattice matching layer is provided. In other embodiments, either the first or second transition layer is provided. In other embodiments, neither the first or second transition layer is provided.

[0085] The bandgap width of the first lattice matching layer 281 is greater than the bandgap width of the first quantum well layer and smaller than the bandgap width of the first barrier layer. The conduction band energy level of the first lattice matching layer 281 is higher than the conduction band energy level of the first quantum well layer and smaller than the conduction band energy level of the first barrier layer. The lattice of the first lattice matching layer 281 is lattice-matched to that of the semiconductor substrate layer 200. The bandgap width of the second lattice matching layer 282 is greater than the bandgap width of the second quantum well layer and smaller than the bandgap width of the second barrier layer. The conduction band energy level of the second lattice matching layer 282 is higher than the conduction band energy level of the second quantum well layer and smaller than the conduction band energy level of the second barrier layer. The lattice of the second lattice matching layer 282 is lattice-matched to that of the semiconductor substrate layer 200.

[0086] The provision of the first lattice matching layer 281 can prevent epitaxial defects introduced by changes in the material system of the first barrier layer and the insertion layer 260, thereby reducing the defect density in the insertion layer 260. The provision of the second lattice matching layer 282 can prevent epitaxial defects introduced by changes in the material system of the second barrier layer and the insertion layer 260, thereby reducing the defect density in the second barrier layer.

[0087] In one embodiment, the material of the first lattice matching layer 281 includes In x1 Ga 1-x1 As, the material of the second lattice matching layer 282 includes In x1 Ga 1-x1 As; and / or, the material of the first transition layer 271 includes In 1-y1 Ga y1 As 1-z1 P z1 or In 1-y2-z2 Ga y2 Al z2 As, the material of the second transition layer 272 includes In 1-y1 Ga y1 As 1-z1 P z1 or In 1-y2-z2 Ga y2 Al z2 As.

[0088] In one embodiment, the first transition layer 271 is doped with conductive ions or is not doped with conductive ions. The second transition layer 272 is doped with conductive ions or is not doped with conductive ions.

[0089] In one embodiment, the doping concentration of the conductive ions in the first transition layer 271 is 1.0×10 16 atom / cm 3 ~5.0×10 16 atom / cm 3 , for example 2×10 16 atom / cm 3 The doping concentration of the conductive ions in the second transition layer 272 is 1.0×10 16 atom / cm 3 ~5.0×10 16 atom / cm 3 , for example 2×10 16 atom / cm 3 .

[0090] In one embodiment, the first lattice matching layer 281 is doped with conductive ions, and the second lattice matching layer 282 is doped with conductive ions. The conductive ions in the first lattice matching layer 281 and the second lattice matching layer 282 are as described above for the conductive ions.

[0091] In one embodiment, the thickness of the first lattice matching layer 281 is 10 nm to 40 nm, for example, 20 nm; the thickness of the second lattice matching layer 282 is 10 nm to 40 nm, for example, 20 nm; and / or the thickness of the first transition layer 271 is 0.05 μm to 0.2 μm, and the thickness of the second transition layer 272 is 0.05 μm to 0.2 μm.

[0092] In one embodiment, the first transition layer 271 includes multiple stacked first sub-transition layers. The conduction band energy levels of the multiple stacked first sub-transition layers gradually increase from the first superlattice active layer 231 to the insertion layer 260. This provides advantages such as achieving a gradual energy band transition, reducing interface resistance, lowering the operating voltage of the semiconductor light-emitting structure, and suppressing thermal inversion and mode hopping.

[0093] In one specific embodiment, the first transition layer 271 includes three stacked first sub-transition layers, and the conduction band energy levels of the three first sub-transition layers increase gradually from the first superlattice active layer 231 to the insertion layer 260. In other examples, the number of first sub-transition layers is not limited.

[0094] In other embodiments, the first transition layer 271 is a single-layer structure, and the conduction band energy level of the first transition layer 271 is constant in the thickness direction.

[0095] In one embodiment, the second transition layer 272 includes multiple stacked second sub-transition layers. The conduction band energy levels of the multiple stacked second sub-transition layers gradually increase from the second superlattice active layer 232 to the insertion layer 260. This provides advantages such as achieving a gradual energy band transition, reducing interface resistance, lowering the operating voltage of the semiconductor light-emitting structure, and suppressing thermal inversion and mode hopping.

[0096] In one specific embodiment, the number of stacked second sub-transition layers in the second transition layer 272 is three, and the conduction band energy levels of the three second sub-transition layers increase gradually from the second superlattice active layer 232 to the insertion layer 260. In other embodiments, the number of second sub-transition layers is not limited.

[0097] In other embodiments, the second transition layer 272 is a single-layer structure, and the conduction band energy level of the second transition layer 272 is constant in the thickness direction.

[0098] The first transition layer 271 has the function of reducing interface scattering of majority carriers, thereby enabling the majority carriers to be transmitted between the first superlattice active layer 231 and the second superlattice active layer 232. The second transition layer 272 has the function of reducing interface scattering of majority carriers, thereby enabling the majority carriers to be transmitted between the first superlattice active layer 231 and the second superlattice active layer 232.

[0099] In one embodiment, the semiconductor light emitting structure further includes: a third lattice matching layer 283 located between the first superlattice active layer 231 and the first waveguide layer 220, and a third transition layer 273 located between the third lattice matching layer 283 and the first waveguide layer 220, wherein the third lattice matching layer 283 is in contact with the first superlattice active layer 231, and the conduction band energy level of the third transition layer 273 is higher than the conduction band energy level of the third lattice matching layer 283 and lower than the conduction band energy level of the first waveguide layer 220. energy level; and, the semiconductor light emitting structure further includes: a fourth lattice matching layer 284 located between the second superlattice active layer 232 and the second waveguide layer 240, and a fourth transition layer 274 located between the fourth lattice matching layer 284 and the second waveguide layer 240, wherein the fourth lattice matching layer 284 contacts the second superlattice active layer 232, and a conduction band energy level of the fourth transition layer 274 is higher than the conduction band energy level of the fourth lattice matching layer 284 and lower than the conduction band energy level of the second waveguide layer 240.

[0100] The bandgap width of the third transition layer 273 is greater than the bandgap width of the third lattice matching layer 283 and smaller than the bandgap width of the first waveguide layer 220. The bandgap width of the fourth transition layer 274 is greater than the bandgap width of the fourth lattice matching layer 284 and smaller than the bandgap width of the second waveguide layer 240.

[0101] In other embodiments, the semiconductor light emitting structure further includes: a third lattice matching layer and a third transition layer; or, the semiconductor light emitting structure further includes: a fourth lattice matching layer and a fourth transition layer.

[0102] In other embodiments, the third lattice matching layer, the third transition layer, the fourth lattice matching layer, and the fourth transition layer may not be provided.

[0103] In other embodiments, the third and fourth lattice matching layers are provided, but the third and fourth transition layers are not provided. In other embodiments, one of the third and fourth lattice matching layers is provided. In other embodiments, the third and fourth lattice matching layers are not provided. In other embodiments, one of the third and fourth transition layers is provided. In other embodiments, the third and fourth transition layers are not provided.

[0104] The bandgap width of the third lattice-matching layer 283 is greater than the bandgap width of the first quantum well layer and smaller than the bandgap width of the first barrier layer. The conduction band energy level of the third lattice-matching layer 283 is higher than the conduction band energy level of the first quantum well layer and smaller than the conduction band energy level of the first barrier layer. The lattice of the third lattice-matching layer 283 is lattice-matched to that of the semiconductor substrate layer 200. The bandgap width of the fourth lattice-matching layer 284 is greater than the bandgap width of the second quantum well layer and smaller than the bandgap width of the second barrier layer. The conduction band energy level of the fourth lattice-matching layer 284 is higher than the conduction band energy level of the second quantum well layer and smaller than the conduction band energy level of the second barrier layer. The lattice of the fourth lattice-matching layer 284 is lattice-matched to that of the semiconductor substrate layer 200.

[0105] The third lattice matching layer 283 prevents epitaxial defects from being introduced by material changes in the first barrier layer and the first waveguide layer 220, thereby reducing the defect density in the first barrier layer. The fourth lattice matching layer 284 prevents epitaxial defects from being introduced by material changes in the second barrier layer and the second waveguide layer 240, thereby reducing the defect density in the second waveguide layer 240.

[0106] In one embodiment, the material of the third lattice matching layer 283 includes In x1 Ga 1-x1 As, the material of the fourth lattice matching layer 284 includes In x1 Ga 1-x1 As; and / or, the material of the third transition layer 273 includes In 1-y3Ga y3 As 1-z3 P z3 or In 1-y4-z4 Ga y4 Al z4 As; the material of the fourth transition layer 274 includes In 1-y3 Ga y3 As 1-z3 P z3 or In 1-y4-z4 Ga y4 Al z4 As.

[0107] In one embodiment, the third transition layer 273 is doped with conductive ions or is not doped with conductive ions. The fourth transition layer 274 is doped with conductive ions or is not doped with conductive ions.

[0108] In one embodiment, the doping concentration of the conductive ions in the third transition layer 273 is 1.0×10 16 atom / cm 3 ~5.0×10 16 atom / cm 3 , for example 2×10 16 atom / cm 3 The doping concentration of the conductive ions in the fourth transition layer 274 is 1.0×10 16 atom / cm 3 ~5.0×10 16 atom / cm 3 , for example 2×10 16 atom / cm 3 .

[0109] In one embodiment, conductive ions are doped into the third lattice matching layer 283. Conductive ions are doped into the fourth lattice matching layer 284. The conductive ions in the third lattice matching layer 283 and the fourth lattice matching layer 284 are as described above for the conductive ions.

[0110] In one embodiment, the thickness of the third lattice matching layer 283 is 10 nm to 40 nm, for example, 20 nm; the thickness of the fourth lattice matching layer 284 is 10 nm to 40 nm, for example, 20 nm; and / or the thickness of the third transition layer 273 is 0.05 μm to 0.2 μm, and the thickness of the fourth transition layer 274 is 0.05 μm to 0.2 μm.

[0111] In one embodiment, the third transition layer 273 includes multiple stacked third sub-transition layers. The conduction band energy levels of the multiple stacked third sub-transition layers decrease layer by layer from the first waveguide layer 220 to the first superlattice active layer 231. This provides advantages such as achieving a gradual energy band transition, reducing interface resistance, lowering the operating voltage of the semiconductor light-emitting structure, and suppressing thermal inversion and mode hopping.

[0112] In one specific embodiment, the third transition layer 273 includes three stacked third sub-transition layers. The conduction band energy levels of the three third sub-transition layers decrease gradually from the first waveguide layer 220 to the first superlattice active layer 231. In other embodiments, the number of third sub-transition layers is not limited.

[0113] In other embodiments, the third transition layer 273 is a single-layer structure, and the conduction band energy level of the third transition layer 273 is constant in the thickness direction.

[0114] In one embodiment, the fourth transition layer 274 includes multiple stacked fourth sub-transition layers. The conduction band energy levels of the multiple stacked fourth sub-transition layers decrease layer by layer from the second waveguide layer 240 to the second superlattice active layer 232. This provides advantages such as achieving a gradual energy band transition, reducing interface resistance, lowering the operating voltage of the semiconductor light-emitting structure, and suppressing thermal inversion and mode hopping.

[0115] In one specific embodiment, the fourth transition layer 274 includes three stacked fourth sub-transition layers. The conduction band energy levels of the three fourth sub-transition layers decrease gradually from the second waveguide layer 240 to the second superlattice active layer 232. In other embodiments, the number of fourth sub-transition layers is not limited.

[0116] In other embodiments, the fourth transition layer 274 is a single-layer structure, and the conduction band energy level of the fourth transition layer 274 is constant in the thickness direction.

[0117] The third transition layer 273 reduces interface scattering of majority carriers, enabling them to propagate between the first superlattice active layer 231 and the first waveguide layer 220. The fourth transition layer 274 reduces interface scattering of majority carriers, enabling them to propagate between the second superlattice active layer 232 and the second waveguide layer 240.

[0118] In this embodiment, the active layer, insertion layer, second waveguide layer, and second confinement layer are located on a side of a portion of the first waveguide layer facing away from the first confinement layer. The semiconductor light-emitting structure further includes an insulating epitaxial layer located on the first waveguide layer on both sides of the active layer, insertion layer, second waveguide layer, and second confinement layer in the width direction. The thermal conductivity of the insulating epitaxial layer is greater than that of the active layer.

[0119] In one embodiment, the insulating epitaxial layer is made of a material including InP doped with Fe. The insulating epitaxial layer is non-conductive, and carriers in the active layer 230 do not pass through the insulating epitaxial layer.

[0120] In one embodiment, the semiconductor light-emitting structure further includes a contact layer located on a surface of the second confinement layer facing away from the second waveguide layer. In one embodiment, the contact layer is an InP contact layer, and the contact layer is doped with conductive ions, wherein the doping concentration of the conductive ions in the contact layer is greater than the doping concentration of the conductive ions in the second confinement layer.

[0121] In one embodiment, the thickness of the contact layer is 0.5 μm to 2 μm, for example, 1 μm.

[0122] In one embodiment, the doping concentration of the conductive ions in the contact layer is 4×10 18 atom / cm 3 ~2×10 19 atom / cm 3 , for example 8×10 18 atom / cm 3 .

[0123] In this embodiment, the semiconductor light-emitting structure also includes: a front electrode located on the side of the second restriction layer 250 away from the semiconductor substrate layer 200. Optionally, the front electrode is located on the surface of the contact layer away from the second restriction layer 250; and a back electrode located on the side of the semiconductor substrate layer 200 away from the first restriction layer 210.

[0124] Example 2

[0125] The difference between this embodiment and Embodiment 1 is that: referring to Figure 3, the first superlattice active layer 231 includes a first sub-superlattice region 231a and a second sub-superlattice region 231b, the second sub-superlattice region 231b is located on the side surface of the first sub-superlattice region 231a away from the first waveguide layer 220, and the doping concentration of conductive ions in the second sub-superlattice region 231b is greater than the doping concentration of conductive ions in the first sub-superlattice region 231a; and, the second superlattice active layer 232 includes a third sub-superlattice region 232b and a fourth sub-superlattice region 232a, the fourth sub-superlattice region 232a is located on the side surface of the third sub-superlattice region 232b away from the insertion layer 260, and the doping concentration of conductive ions in the third sub-superlattice region 232b is greater than the doping concentration of conductive ions in the fourth sub-superlattice region 232a.

[0126] In other embodiments, the first superlattice active layer includes a first sub-superlattice region and a second sub-superlattice region, the second sub-superlattice region is located on a side surface of the first sub-superlattice region away from the first waveguide layer, and the doping concentration of conductive ions in the second sub-superlattice region is greater than the doping concentration of conductive ions in the first sub-superlattice region; or, the second superlattice active layer includes a third sub-superlattice region and a fourth sub-superlattice region, the fourth sub-superlattice region is located on a side surface of the third sub-superlattice region away from the insertion layer, and the doping concentration of conductive ions in the third sub-superlattice region is greater than the doping concentration of conductive ions in the fourth sub-superlattice region.

[0127] The doping concentration of conductive ions in the second sub-superlattice region 231b is greater than the doping concentration of conductive ions in the first sub-superlattice region 231a. The waveguide absorption loss of the second sub-superlattice region 231b to the light field is greater than the waveguide absorption loss of the first sub-superlattice region 231a to the light field. The difference between the optical loss of the second sub-superlattice region 231b to the higher-order modes and the optical loss of the first sub-superlattice region 231a to the higher-order modes is greater than the difference between the optical loss of the second sub-superlattice region 231b to the fundamental mode and the optical loss of the first sub-superlattice region 231a to the fundamental mode. This effectively suppresses the higher-order modes and improves the beam quality of the semiconductor light-emitting structure.

[0128] The doping concentration of conductive ions in the third sub-superlattice region 232b is greater than the doping concentration of conductive ions in the fourth sub-superlattice region 232a. The waveguide absorption loss of the third sub-superlattice region 232b to the light field is greater than the waveguide absorption loss of the fourth sub-superlattice region 232a to the light field. The difference between the optical loss of the third sub-superlattice region 232b to the higher-order modes and the optical loss of the fourth sub-superlattice region 232a to the higher-order modes is greater than the difference between the optical loss of the third sub-superlattice region 232b to the fundamental mode and the optical loss of the fourth sub-superlattice region 232a to the fundamental mode. This effectively suppresses the higher-order modes and improves the beam quality of the semiconductor light-emitting structure.

[0129] The third sub-superlattice region 232b of the second sub-superlattice region 231b can generate a certain gain, thereby reducing the threshold current density and improving the slope efficiency.

[0130] In one embodiment, the doping concentration of conductive ions in the third sub-superlattice region 232b is 20% to 50% higher than the doping concentration of conductive ions in the fourth sub-superlattice region 232a; and / or the doping concentration of conductive ions in the second sub-superlattice region 231b is 20% to 50% higher than the doping concentration of conductive ions in the first sub-superlattice region 231a. The significance of this numerical range is that if the doping concentration of conductive ions in the third sub-superlattice region 232b is too low, the degree of suppression of high-order modes by the third sub-superlattice region 232b is weakened; if the doping concentration of conductive ions in the third sub-superlattice region 232b is too high, the overlap between the current operating range of the third sub-superlattice region 232b and the current operating range of the fourth sub-superlattice region 232a is small. If the doping concentration of conductive ions in the second sub-superlattice region 231b is too low, the degree of suppression of high-order modes by the second sub-superlattice region 231b will be weakened. If the doping concentration of conductive ions in the second sub-superlattice region 231b is too high, the overlapping range of the current operating range of the second sub-superlattice region 231b and the current operating range of the first sub-superlattice region 231a will be smaller.

[0131] The contents of this embodiment that are the same as those of embodiment 1 will not be described in detail.

[0132] Example 3

[0133] This embodiment provides a method for a semiconductor light-emitting structure, comprising: providing a semiconductor substrate layer; sequentially forming a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer on the semiconductor substrate layer; the step of forming the active layer comprising: sequentially stacking a first superlattice active layer and a second superlattice active layer; the method for preparing the semiconductor light-emitting structure further comprising: before forming the second superlattice active layer, forming an insertion layer on a side of the first superlattice active layer facing away from the first waveguide layer; the refractive index of the insertion layer being less than the effective refractive index of the first superlattice active layer and less than the effective refractive index of the second superlattice active layer.

[0134] In one embodiment, the method for preparing the semiconductor light-emitting structure further includes: before forming the insertion layer, forming a first lattice matching layer on a surface of the first superlattice active layer facing away from the first waveguide layer; forming a first transition layer on a side of the first lattice matching layer facing away from the first waveguide layer; the conduction band energy level of the first transition layer is higher than the conduction band energy level of the first lattice matching layer and lower than the conduction band energy level of the insertion layer; and the step of forming the insertion layer is: forming the insertion layer on a surface of the first transition layer facing away from the first waveguide layer.

[0135] In one embodiment, the step of forming a first transition layer on a side of the first lattice matching layer facing away from the first waveguide layer includes forming a plurality of stacked first sub-transition layers; and in an arrangement direction from the first superlattice active layer to the insertion layer, the conduction band energy levels of the plurality of stacked first sub-transition layers increase layer by layer.

[0136] In other embodiments, the first transition layer is a single-layer structure, and the conduction band energy level of the first transition layer is constant in the thickness direction.

[0137] In other embodiments, the first transition layer is not provided.

[0138] In one embodiment, the method for preparing the semiconductor light-emitting structure further includes: before forming the second superlattice active layer, forming a second transition layer on the side of the insertion layer facing away from the first superlattice active layer; forming a second lattice matching layer on the side of the second transition layer facing away from the first superlattice active layer; the conduction band energy level of the second transition layer is higher than the conduction band energy level of the second lattice matching layer and lower than the conduction band energy level of the insertion layer; the step of forming the second superlattice active layer is: forming the second superlattice active layer on the surface of the second lattice matching layer on the side facing away from the first superlattice active layer.

[0139] In one embodiment, the step of forming a second transition layer on the side of the insertion layer away from the first superlattice active layer includes: forming a plurality of stacked second sub-transition layers; in the arrangement direction from the second superlattice active layer to the insertion layer, the conduction band energy levels of the plurality of stacked second sub-transition layers increase layer by layer.

[0140] In other embodiments, the second transition layer is a single-layer structure, and the conduction band energy level of the second transition layer is constant in the thickness direction.

[0141] In other embodiments, the second transition layer is not provided.

[0142] In other embodiments, the first and second lattice matching layers are provided, but the first and second transition layers are not provided. In other embodiments, either the first or second lattice matching layer is provided. In other embodiments, neither the first or second lattice matching layer is provided. In other embodiments, either the first or second transition layer is provided. In other embodiments, neither the first or second transition layer is provided.

[0143] In one embodiment, the method for preparing the semiconductor light-emitting structure further includes: before forming the first superlattice active layer, forming a third transition layer on a side of the first waveguide layer facing away from the first confinement layer; forming a third lattice matching layer on a side of the third transition layer facing away from the first confinement layer; the conduction band energy level of the third transition layer is higher than the conduction band energy level of the third lattice matching layer and lower than the conduction band energy level of the first waveguide layer; and the step of forming the first superlattice active layer includes forming the first superlattice active layer on a surface of the third lattice matching layer facing away from the first confinement layer.

[0144] In one embodiment, the step of forming a third transition layer on a side of the first waveguide layer facing away from the first confinement layer includes: forming a plurality of stacked third sub-transition layers, wherein the conduction band energy levels of the plurality of stacked third sub-transition layers decrease layer by layer in an arrangement direction from the first waveguide layer to the first superlattice active layer.

[0145] In other embodiments, the third transition layer is a single-layer structure, and the conduction band energy level of the third transition layer is constant in the thickness direction.

[0146] In other embodiments, the third transition layer is not provided.

[0147] In one embodiment, the method for preparing the semiconductor light-emitting structure further includes: before forming the second waveguide layer, forming a fourth lattice matching layer on a surface of the second superlattice active layer facing away from the first superlattice active layer; forming a fourth transition layer on a side of the fourth lattice matching layer facing away from the first superlattice active layer, wherein a conduction band energy level of the fourth transition layer is higher than the conduction band energy level of the fourth lattice matching layer and lower than the conduction band energy level of the second waveguide layer; and the step of forming the second waveguide layer comprises: forming the second waveguide layer on a side of the fourth transition layer facing away from the first superlattice active layer.

[0148] In one embodiment, the step of forming a fourth transition layer on a side of the fourth lattice matching layer facing away from the first superlattice active layer includes: forming a plurality of stacked fourth sub-transition layers, wherein the conduction band energy levels of the plurality of stacked fourth sub-transition layers decrease layer by layer in an arrangement direction from the second waveguide layer to the second superlattice active layer.

[0149] In other embodiments, the fourth transition layer is a single-layer structure, and the conduction band energy level of the fourth transition layer is constant in the thickness direction.

[0150] In other embodiments, the fourth transition layer is not provided.

[0151] In other embodiments, the third and fourth lattice matching layers are provided, but the third and fourth transition layers are not provided. In other embodiments, one of the third and fourth lattice matching layers is provided. In other embodiments, the third and fourth lattice matching layers are not provided. In other embodiments, one of the third and fourth transition layers is provided. In other embodiments, the third and fourth transition layers are not provided.

[0152] In one embodiment, the step of forming the first superlattice active layer includes: sequentially forming a stacked first sub-superlattice region and a second sub-superlattice region, the second sub-superlattice region being located on a side surface of the first sub-superlattice region away from the first waveguide layer, and the doping concentration of conductive ions in the second sub-superlattice region being greater than the doping concentration of conductive ions in the first sub-superlattice region; and / or, the step of forming the second superlattice active layer includes: sequentially forming a stacked third sub-superlattice region and a fourth sub-superlattice region, the fourth sub-superlattice region being located on a side surface of the third sub-superlattice region away from the insertion layer, and the doping concentration of conductive ions in the third sub-superlattice region being greater than the doping concentration of conductive ions in the fourth sub-superlattice region.

[0153] In another embodiment, the doping concentration of the conductive ions in the first superlattice active layer is constant in the thickness direction. The doping concentration of the conductive ions in the second superlattice active layer is constant in the thickness direction.

[0154] In one embodiment, the process further includes: forming a mask layer on a side of a portion of the second confinement layer facing away from the second waveguide layer; etching the second confinement layer, the second waveguide layer, the active layer, and the insertion layer using the mask layer as a mask until the first waveguide layer is exposed; and then removing the mask layer. In a specific embodiment, the second confinement layer, the second waveguide layer, the active layer, the insertion layer, and a portion of the thickness of the first waveguide layer are etched using the mask layer as a mask.

[0155] In one embodiment, when forming the first lattice matching layer and the first transition layer, the first lattice matching layer and the first transition layer are also etched during the etching of the second confinement layer, the second waveguide layer, the active layer and the insertion layer using the mask layer as a mask.

[0156] In one embodiment, when forming the second lattice matching layer and the second transition layer, the second confinement layer, the second waveguide layer, the active layer and the insertion layer are etched using the mask layer as a mask, and the second lattice matching layer and the second transition layer are also etched.

[0157] In one embodiment, when forming the third lattice matching layer and the third transition layer, the third lattice matching layer and the third transition layer are also etched during the process of etching the second confinement layer, the second waveguide layer, the active layer and the insertion layer using the mask layer as a mask.

[0158] In one embodiment, when forming the fourth lattice matching layer and the fourth transition layer, the fourth lattice matching layer and the fourth transition layer are also etched during the process of etching the second confinement layer, the second waveguide layer, the active layer and the insertion layer using the mask layer as a mask.

[0159] In one embodiment, the method for preparing the semiconductor light-emitting structure further includes: after etching the second confinement layer, the second waveguide layer, the active layer, and the insertion layer using the mask layer as a mask, forming an insulating epitaxial layer on the first waveguide layer on both sides of the active layer, the insertion layer, the second waveguide layer, and the second confinement layer in the width direction, wherein the thermal conductivity of the insulating epitaxial layer is greater than the thermal conductivity of the active layer; forming an anti-reflection film on the front cavity surface of the semiconductor light-emitting structure; and forming a reflective film on the back cavity surface of the semiconductor light-emitting structure.

[0160] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of this application.

Claims

1. A semiconductor light-emitting structure, characterized in that: include: A semiconductor substrate layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; the active layer comprises a first superlattice active layer and a second superlattice active layer stacked, the second superlattice active layer being located on a side of the first superlattice active layer facing away from the first waveguide layer; The semiconductor light emitting structure further comprises: an insertion layer located between the second superlattice active layer and the first superlattice active layer, wherein the refractive index of the insertion layer is smaller than the effective refractive index of the first superlattice active layer and smaller than the effective refractive index of the second superlattice active layer; The thickness of the insertion layer is 50% to 150% of the thickness of the first superlattice active layer, the thickness of the insertion layer is 50% to 150% of the thickness of the second superlattice active layer, and the thickness of the insertion layer is 15% to 50% of the emission wavelength of the semiconductor light-emitting structure.

2. The semiconductor light emitting structure according to claim 1, characterized in that: The semiconductor light emitting structure further includes: a first lattice matching layer located between the first superlattice active layer and the insertion layer, and a first transition layer located between the first lattice matching layer and the insertion layer, wherein the first lattice matching layer is in contact with the first superlattice active layer, and a conduction band energy level of the first transition layer is higher than a conduction band energy level of the first lattice matching layer and lower than a conduction band energy level of the insertion layer; And / or, the semiconductor light-emitting structure further includes: a second lattice matching layer located between the second superlattice active layer and the insertion layer, and a second transition layer located between the second lattice matching layer and the insertion layer, the second lattice matching layer and the second superlattice active layer are in contact, and the conduction band energy level of the second transition layer is higher than the conduction band energy level of the second lattice matching layer and lower than the conduction band energy level of the insertion layer.

3. The semiconductor light emitting structure according to claim 2, characterized in that: The first transition layer includes multiple stacked first sub-transition layers; in the arrangement direction from the first superlattice active layer to the insertion layer, the conduction band energy levels of the multiple stacked first sub-transition layers increase layer by layer; or, the first transition layer is a single-layer structure, and the conduction band energy level of the first transition layer is constant in the thickness direction.

4. The semiconductor light emitting structure according to claim 2, wherein: The second transition layer includes multiple stacked second sub-transition layers; in the arrangement direction from the second superlattice active layer to the insertion layer, the conduction band energy levels of the multiple stacked second sub-transition layers increase layer by layer; or, the second transition layer is a single-layer structure, and the conduction band energy level of the second transition layer is constant in the thickness direction.

5. The semiconductor light emitting structure according to claim 1, wherein: The semiconductor light-emitting structure further includes: a third lattice matching layer located between the first superlattice active layer and the first waveguide layer; and a third transition layer located between the third lattice matching layer and the first waveguide layer, wherein the third lattice matching layer is in contact with the first superlattice active layer, and a conduction band energy level of the third transition layer is higher than a conduction band energy level of the third lattice matching layer and lower than a conduction band energy level of the first waveguide layer. And / or, the semiconductor light-emitting structure further includes: a fourth lattice matching layer located between the second superlattice active layer and the second waveguide layer, and a fourth transition layer located between the fourth lattice matching layer and the second waveguide layer, the fourth lattice matching layer and the second superlattice active layer being in contact with each other, and a conduction band energy level of the fourth transition layer being higher than a conduction band energy level of the fourth lattice matching layer and lower than a conduction band energy level of the second waveguide layer.

6. The semiconductor light emitting structure according to claim 5, characterized in that: The third transition layer includes multiple stacked third sub-transition layers; in the arrangement direction from the first waveguide layer to the first superlattice active layer, the conduction band energy levels of the multiple stacked third sub-transition layers decrease layer by layer; or, the third transition layer is a single-layer structure, and the conduction band energy level of the third transition layer is constant in the thickness direction.

7. The semiconductor light emitting structure according to claim 5, characterized in that: The fourth transition layer includes multiple stacked fourth sub-transition layers; in the arrangement direction from the second waveguide layer to the second superlattice active layer, the conduction band energy levels of the multiple stacked fourth sub-transition layers decrease layer by layer; or, the fourth transition layer is a single-layer structure, and the conduction band energy level of the fourth transition layer is constant in the thickness direction.

8. The semiconductor light emitting structure according to claim 1, wherein: The insertion layer is an InP insertion layer doped with conductive ions or not doped with conductive ions, or the insertion layer is an InAlAs insertion layer doped with conductive ions or not doped with conductive ions, or the insertion layer is an InGaAlAs insertion layer doped with conductive ions or not doped with conductive ions.

9. The semiconductor light emitting structure according to claim 1, wherein: The thickness of the insertion layer is 0.6 μm to 1.2 μm.

10. The semiconductor light emitting structure according to claim 1, wherein: The first superlattice active layer includes multiple first barrier layers and multiple first quantum well layers, the first barrier layers and the first quantum well layers are alternately stacked, the top layer and the bottom layer of the first superlattice active layer are both first barrier layers, and the conduction band energy level of the first quantum well layer is lower than the conduction band energy level of the first barrier layer; The second superlattice active layer includes multiple second barrier layers and multiple second quantum well layers, the second barrier layers and the second quantum well layers are alternately stacked, the top and bottom layers of the second superlattice active layer are both second barrier layers, and the conduction band energy level of the second quantum well layer is lower than the conduction band energy level of the second barrier layer; The conduction band energy level of the insertion layer is higher than the conduction band energy level of the first quantum well layer and lower than the conduction band energy level of the first barrier layer, and the conduction band energy level of the insertion layer is higher than the conduction band energy level of the second quantum well layer and lower than the conduction band energy level of the second barrier layer.

11. The semiconductor light emitting structure according to claim 1, wherein: The thickness of the first superlattice active layer is 0.8 μm to 1.0 μm; and the thickness of the second superlattice active layer is 0.8 μm to 1.0 μm.

12. The semiconductor light emitting structure according to claim 1, wherein: The width of the active layer is 8 μm to 10 μm.

13. The semiconductor light emitting structure according to claim 1, wherein: The first superlattice active layer includes a first sub-superlattice region and a second sub-superlattice region, the second sub-superlattice region is located on a side surface of the first sub-superlattice region away from the first waveguide layer, and the doping concentration of conductive ions in the second sub-superlattice region is greater than the doping concentration of conductive ions in the first sub-superlattice region; and / or, the second superlattice active layer includes a third sub-superlattice region and a fourth sub-superlattice region, the fourth sub-superlattice region is located on a side surface of the third sub-superlattice region away from the insertion layer, and the doping concentration of conductive ions in the third sub-superlattice region is greater than the doping concentration of conductive ions in the fourth sub-superlattice region.

14. The semiconductor light emitting structure according to claim 13, wherein: The doping concentration of conductive ions in the third sub-superlattice region is 20% to 50% higher than the doping concentration of conductive ions in the fourth sub-superlattice region; and / or the doping concentration of conductive ions in the second sub-superlattice region is 20% to 50% higher than the doping concentration of conductive ions in the first sub-superlattice region.

15. The semiconductor light emitting structure according to claim 1, wherein: An intermediate surface between a surface of the first superlattice active layer facing away from the second superlattice active layer and a surface of the second superlattice active layer facing away from the first superlattice active layer is located in the insertion layer; The distance from the surface of the first superlattice active layer facing away from the second superlattice active layer to the intermediate plane is equal to the distance from the surface of the second superlattice active layer facing away from the first superlattice active layer to the intermediate plane.

16. A method for preparing the semiconductor light emitting structure according to any one of claims 1 to 15, characterized in that: include: providing a semiconductor substrate layer; forming a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer and a second confinement layer in sequence on the semiconductor substrate layer; The step of forming the active layer includes: sequentially stacking a first superlattice active layer and a second superlattice active layer; The method for preparing the semiconductor light-emitting structure further includes: before forming the second superlattice active layer, forming an insertion layer on a side of the first superlattice active layer facing away from the first waveguide layer; the refractive index of the insertion layer is smaller than the effective refractive index of the first superlattice active layer and smaller than the effective refractive index of the second superlattice active layer.

17. The method for preparing a semiconductor light emitting structure according to claim 16, characterized in that: Also includes: Before forming the insertion layer, forming a first lattice matching layer on a surface of the first superlattice active layer facing away from the first waveguide layer; forming a first transition layer on a side of the first lattice matching layer facing away from the first waveguide layer; wherein a conduction band energy level of the first transition layer is higher than a conduction band energy level of the first lattice matching layer and lower than a conduction band energy level of the insertion layer; The step of forming the insertion layer is: forming the insertion layer on a surface of the first transition layer facing away from the first waveguide layer; And / or, further comprising: before forming the second superlattice active layer, forming a second transition layer on a side of the insertion layer away from the first superlattice active layer; A second lattice matching layer is formed on a side of the second transition layer facing away from the first superlattice active layer; the conduction band energy level of the second transition layer is higher than the conduction band energy level of the second lattice matching layer and lower than the conduction band energy level of the insertion layer; the step of forming the second superlattice active layer is: forming the second superlattice active layer on a surface of the second lattice matching layer facing away from the first superlattice active layer.

18. The method for preparing a semiconductor light emitting structure according to claim 17, wherein: The step of forming a first transition layer on a side of the first lattice matching layer facing away from the first waveguide layer includes forming a plurality of stacked first sub-transition layers; in an arrangement direction from the first superlattice active layer to the insertion layer, the conduction band energy levels of the plurality of stacked first sub-transition layers increase layer by layer.

19. The method for preparing a semiconductor light emitting structure according to claim 17, wherein: The step of forming a second transition layer on the side of the insertion layer away from the first superlattice active layer includes: forming a plurality of stacked second sub-transition layers; in the arrangement direction from the second superlattice active layer to the insertion layer, the conduction band energy levels of the plurality of stacked second sub-transition layers increase layer by layer.

20. The method for preparing a semiconductor light emitting structure according to claim 16, wherein: Also includes: Before forming the first superlattice active layer, forming a third transition layer on a side of the first waveguide layer away from the first confinement layer; forming a third lattice matching layer on a side of the third transition layer away from the first confinement layer; the conduction band energy level of the third transition layer is higher than the conduction band energy level of the third lattice matching layer and lower than the conduction band energy level of the first waveguide layer; and forming a first superlattice active layer comprises: forming the first superlattice active layer on a surface of the third lattice matching layer away from the first confinement layer; And / or, further comprising: before forming the second waveguide layer, forming a fourth lattice matching layer on a surface of the second superlattice active layer facing away from the first superlattice active layer; In a fourth transition layer on a side of the fourth lattice matching layer facing away from the first superlattice active layer, a conduction band energy level of the fourth transition layer is higher than the conduction band energy level of the fourth lattice matching layer and lower than the conduction band energy level of the second waveguide layer; and the step of forming the second waveguide layer comprises: forming the second waveguide layer on a side of the fourth transition layer facing away from the first superlattice active layer.

21. The method for preparing a semiconductor light emitting structure according to claim 20, characterized in that: The step of forming a third transition layer on a side of the first waveguide layer away from the first confinement layer includes: forming a plurality of stacked third sub-transition layers, wherein the conduction band energy levels of the plurality of stacked third sub-transition layers decrease layer by layer in an arrangement direction from the first waveguide layer to the first superlattice active layer.

22. The method for preparing a semiconductor light emitting structure according to claim 20, characterized in that: The step of forming a fourth transition layer on a side of the fourth lattice matching layer facing away from the first superlattice active layer includes: forming a plurality of stacked fourth sub-transition layers, wherein the conduction band energy levels of the plurality of stacked fourth sub-transition layers decrease layer by layer in an arrangement direction from the second waveguide layer to the second superlattice active layer.

23. The method for preparing a semiconductor light emitting structure according to claim 16, wherein: The step of forming the first superlattice active layer includes: sequentially forming a stacked first sub-superlattice region and a second sub-superlattice region, wherein the second sub-superlattice region is located on a surface of the first sub-superlattice region facing away from the first waveguide layer, and the doping concentration of conductive ions in the second sub-superlattice region is greater than the doping concentration of conductive ions in the first sub-superlattice region; And / or, the step of forming the second superlattice active layer includes: sequentially forming a stacked third sub-superlattice region and a fourth sub-superlattice region, the fourth sub-superlattice region being located on a side surface of the third sub-superlattice region away from the insertion layer, the doping concentration of conductive ions in the third sub-superlattice region being greater than the doping concentration of conductive ions in the fourth sub-superlattice region.

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