Semiconductor laser and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor lasers, and discloses a semiconductor laser and a preparation method thereof, and the semiconductor laser comprises an epitaxial structure which comprises a substrate, a buffer layer, a lower limiting layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper limiting layer and an ohmic contact layer which are stacked from bottom to top; the back electrode is formed on the surface of one side, far away from the buffer layer, of the substrate; the side, close to the ohmic contact layer, of the epitaxial structure is etched to form a first current injection window, the etching end point of the first current injection window is the ohmic contact layer, and a plurality of suppression current injection structures are arranged in the edge area of the first current injection window at intervals in the first direction; and the front electrode is formed on the first current injection window and the plurality of suppression current injection structures. According to the invention, the thermal lens effect can be counteracted, a small far-field horizontal divergence angle can be realized, the temperature distribution of the current injection region can be uniform, and the reliability of the semiconductor laser can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor lasers, and in particular to a semiconductor laser and a preparation method thereof. Background Art

[0002] Semiconductor laser is a device that uses semiconductor materials as working materials to generate lasers. It has the advantages of compact structure, long life, high reliability, high electro-optical conversion efficiency, fast modulation rate, wide wavelength range and easy integration. It is widely used in industrial production, laser radar, military attack and defense, optical communication, optical information storage and medical beauty. With the development and progress of society, higher requirements are put forward for the efficiency and reliability of semiconductor lasers in many application fields. For example, in the industrial application of 10,000-watt fiber lasers, for 915 / 976nm semiconductor lasers used for optical pumping, the application end needs semiconductor lasers with higher power, smaller divergence angle and better reliability.

[0003] However, as the driving current and power of the semiconductor laser increase, the temperature of the waveguide area rises, the temperature in the middle of the current injection area is high, and the temperature on both sides is relatively low, which changes the lateral refractive index distribution of the semiconductor laser waveguide layer material. The refractive index of the central area is higher than that of the edge area, which eventually causes the light beam to focus toward the middle during propagation, that is, the thermal lens effect occurs. On the one hand, the thermal lens effect will cause the horizontal far-field divergence angle to increase, affecting the beam quality of the laser output; on the other hand, the strong interaction between the injected carriers and photons in the central area may also reduce the reliability of the semiconductor laser. Summary of the invention

[0004] In view of this, the present invention provides a semiconductor laser and a method for manufacturing the same, so as to reduce the horizontal far-field divergence angle of the semiconductor laser and improve the reliability of the semiconductor laser.

[0005] In a first aspect, the present invention provides a semiconductor laser, comprising: an epitaxial structure, comprising a substrate, a buffer layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and an ohmic contact layer stacked from bottom to top; a back electrode formed on a surface of the substrate away from the buffer layer; a first current injection window is formed by etching a side of the epitaxial structure close to the ohmic contact layer, the end point of etching the first current injection window is the ohmic contact layer, and a plurality of current injection suppression structures are arranged at intervals in the edge area of ​​the first current injection window along a first direction, the first direction being a direction from the front cavity surface to the rear cavity surface; a front electrode is formed on the first current injection window and on the plurality of current injection suppression structures.

[0006] The semiconductor laser provided by the present invention is provided with a plurality of current injection suppression structures at the edge region of the current injection window, so that the equivalent resistance of the edge region of the current injection window is increased, thereby generating additional heat, offsetting the thermal lens effect, achieving a smaller far-field horizontal divergence angle, and being able to make the temperature distribution of the current injection window uniform, thereby improving the reliability of the semiconductor laser.

[0007] In an optional embodiment, the current injection suppression structure is a first non-current injection window formed after an insulating layer is grown on the surface of the ohmic contact layer away from the upper confinement layer.

[0008] In this embodiment, an insulating layer is grown on multiple first non-current injection windows, and current cannot be injected, thereby forming an equivalent channel with higher resistance at the edge of the first current injection window. When a large current is injected, the high resistance means that additional heat will be generated, which will reduce the temperature difference between the edge area and the center area, offsetting the effect of the thermal lens, thereby reducing the horizontal far-field divergence angle.

[0009] In an optional embodiment, a second non-current injection window is also etched on one side of the epitaxial structure close to the ohmic contact layer, the etching end point of the second non-current injection window is the upper limiting layer, the insulating layer is also formed on the second non-current injection window, and the front electrode is also formed on the surface of the side of the insulating layer away from the second non-current injection window, and the current injection suppression structure is the second non-current injection window.

[0010] In this embodiment, after the heavily doped epitaxial part is etched through the second non-current injection window, an insulating layer is grown in the second non-current injection window, which can further prevent the current from expanding laterally through the heavily doped ohmic contact layer under the insulating layer and causing current leakage.

[0011] In an optional embodiment, the thickness of the ohmic contact layer remaining after etching is 200 nm to 500 nm.

[0012] In an optional embodiment, the ohmic contact layer includes a lower ohmic contact layer, a resistance control layer and an upper ohmic contact layer stacked from bottom to top, and the end point of etching the first current injection window is the lower ohmic contact layer; the current injection suppression structure is a second current injection window formed after etching the upper ohmic contact layer, and the end point of etching the second current injection window is the upper ohmic contact layer.

[0013] In this embodiment, compared with the first current injection window, the path through which the current flows in the second current injection window includes a resistance control layer with a higher resistance. When a large current is injected, the high resistance means that additional heat will be generated, which reduces the temperature difference between the edge area and the center area of ​​the first current injection window, offsetting the effect of the thermal lens, thereby reducing the horizontal far-field divergence angle.

[0014] In an optional embodiment, the ohmic contact layer includes a lower ohmic contact layer, a resistance control layer and an upper ohmic contact layer stacked from bottom to top, the end point of etching the first current injection window is the lower ohmic contact layer, and the end of the epitaxial structure close to the upper ohmic contact layer is also etched to form a third non-current injection window and a fourth non-current injection window; the end point of etching the third non-current injection window is the upper limiting layer, the insulating layer is also formed on the third non-current injection window, and the front electrode is also formed on the side surface of the insulating layer away from the third non-current injection window; the fourth non-current injection window is formed after growing an insulating layer on the side surface of the upper ohmic contact layer away from the resistance control layer, and the current injection suppression structure is the third non-current injection window and / or the fourth non-current injection window.

[0015] In this embodiment, the third non-current injection window also etches a portion of the highly doped upper confinement layer, which is applicable to the strip isolation groove area to further prevent the current from expanding laterally through the heavily doped upper confinement layer under the insulating layer, causing current leakage and reducing laser efficiency.

[0016] In an optional embodiment, the doping concentration of the upper ohmic contact layer and the lower ohmic contact layer is 2E19cm -3 To 1E20cm -3 The doping concentration of the resistance control layer is 1E17cm -3 To 1E20cm -3 .

[0017] In an optional implementation, the distance between the current injection suppression structure closest to the rear cavity surface and the edge of the first current injection window in the first direction is 5 μm to 100 μm.

[0018] In an optional embodiment, the spacing between two adjacent current injection suppression structures in the first direction is 10 μm to 200 μm, the ratio of the first spacing to the second spacing is 0.5:1 to 2:1, the first spacing is the spacing between the first suppression current injection structure and the second suppression current injection structure among the three adjacent current injection suppression structures in the first direction, and the second spacing is the spacing between the second suppression current injection structure and the third suppression current injection structure among the three adjacent current injection suppression structures in the first direction.

[0019] In this embodiment, the light intensity distribution in the direction from the front cavity surface to the rear cavity surface may be inconsistent. By controlling the spacing between the multiple first non-current injection windows, the current injection efficiency can be adjusted while effectively reducing the horizontal far-field divergence angle, thereby improving the light output power of the semiconductor laser.

[0020] In an optional implementation, the ratio of the height of the current injection suppression structure to the height of the first current injection window is 1:2 to 1:20.

[0021] In an optional implementation, heights of the plurality of current injection suppression structures vary gradually along the first direction.

[0022] In this embodiment, the heights of the multiple current injection suppression structures vary gradually along the first direction, which can effectively reduce the horizontal far-field divergence angle while increasing the output power of the semiconductor laser.

[0023] In an optional embodiment, the ratio of the height of the current injection suppression structure closest to the front cavity surface to the height of the current injection suppression structure closest to the rear cavity surface is 1:1 to 1:10.

[0024] In an optional embodiment, multiple current injection suppression structures are arranged in a preset area close to the rear cavity surface, and the ratio of the length of the area where the current injection suppression structure is arranged in the first direction to the length of the first current injection window in the first direction is 1:1 to 1:10.

[0025] In an optional implementation, the current injection suppression structure is in the shape of an isosceles trapezoid, an isosceles triangle or a rectangle.

[0026] In an optional embodiment, the width of the current injection suppression structure is 20 μm to 60 μm, and when the shape of the current injection suppression structure is an isosceles trapezoid or an isosceles triangle, the base angle of the shape of the current injection suppression structure is 30° to 60°.

[0027] In a second aspect, the present invention provides a method for preparing a semiconductor laser, the method comprising: providing a substrate; sequentially growing a buffer layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and an ohmic contact layer on a surface of one side of the substrate to form an epitaxial structure; growing a conductive material on a surface of a side of the substrate away from the buffer layer to form a back electrode; etching a side of the epitaxial structure close to the ohmic contact layer to form a first current injection window, the etching end point of the first current injection window being the ohmic contact layer; forming a plurality of current injection suppression structures at the edge of the first current injection window, the plurality of current injection suppression structures being spaced apart along a first direction, the first direction being a direction from a front cavity surface to a rear cavity surface; growing a conductive material on the first current injection window and on the plurality of current injection suppression structures to form a front electrode, so as to prepare the semiconductor laser of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 is a cross-sectional schematic diagram of a semiconductor laser according to an embodiment of the present invention; Figure 2 is a cross-sectional schematic diagram of another semiconductor laser according to an embodiment of the present invention; Figure 3 is a schematic cross-sectional view of an epitaxial structure of a semiconductor laser according to an embodiment of the present invention; Figure 4 is a schematic cross-sectional view of an epitaxial structure of another semiconductor laser according to an embodiment of the present invention; Figure 5 is a schematic top view of a first current injection suppression structure of a semiconductor laser according to an embodiment of the present invention; Figure 6 is a schematic diagram of the shape of a current injection suppression structure according to an embodiment of the present invention; Figure 7 is a schematic top view of a second current injection suppression structure of a semiconductor laser according to an embodiment of the present invention; Figure 8 is a schematic top view of a third current injection suppression structure of a semiconductor laser according to an embodiment of the present invention; Fig. 9 is a schematic top view of a fourth current injection suppression structure of a semiconductor laser according to an embodiment of the present invention; Fig.10 is a top view schematically showing a first current injection suppression structure of another semiconductor laser according to an embodiment of the present invention; Fig.11 is a schematic top view of a second current injection suppression structure of another semiconductor laser according to an embodiment of the present invention; Fig.12 is a top view schematically showing a third current injection suppression structure of another semiconductor laser according to an embodiment of the present invention; Fig.13 4 is a top view schematically showing a fourth current injection suppression structure of another semiconductor laser according to an embodiment of the present invention.

[0030] Figure numerals: 100, semiconductor laser; 110, epitaxial structure; 111, substrate; 112, buffer layer; 113, lower confinement layer; 114, lower waveguide layer; 115, quantum well active layer; 116, upper waveguide layer; 117, upper confinement layer; 118, ohmic contact layer; 1181, lower ohmic contact layer; 1182, resistance control layer; 1183, upper ohmic contact layer; 120, back electrode; 130, insulating layer; 140, front electrode; 151, first current injection window; 152, first non-current injection window; 153, second non-current injection window; 154, second current injection window; 155, third non-current injection window; 156, fourth non-current injection window; 160, heavily doped boss; 170, strip isolation groove. DETAILED DESCRIPTION

[0031] According to the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. The present invention is further described in detail below in conjunction with the drawings and embodiments. It is understandable that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the drawings.

[0032] In the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention. Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified for the purpose of clear expression, and some details may be omitted. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships between them are only exemplary, and may be deviated due to manufacturing tolerances or technical limitations in practice, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs. In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be a middle layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element.

[0033] The semiconductor laser (semiconductor laser chip) provided by the present invention is provided with a plurality of current injection suppression structures at the edge region of the current injection window, so that the equivalent resistance of the edge region of the current injection window is increased, thereby generating additional heat, offsetting the thermal lens effect, achieving a smaller far-field horizontal divergence angle, and being able to make the temperature distribution of the current injection window uniform, thereby improving the reliability of the semiconductor laser.

[0034] like Figure 1 and Figure 2 As shown, the semiconductor laser 100 provided by the present invention includes an epitaxial structure 110 , a back electrode 120 , an insulating layer 130 and a front electrode 140 .

[0035] The epitaxial structure 110 includes a substrate 111, a buffer layer 112, a lower confinement layer 113, a lower waveguide layer 114, a quantum well active layer 115, an upper waveguide layer 116, an upper confinement layer 117 and an ohmic contact layer 118 stacked from bottom to top. The back electrode 120 is located on the surface of the substrate 111 away from the buffer layer 112, the insulating layer 130 is located on a partial area of ​​the surface of the ohmic contact layer 118 away from the upper confinement layer 117, and the front electrode 140 is located on the upper surface of the insulating layer 130 and the upper surface of the ohmic contact layer 118.

[0036] Specifically, the epitaxial structure 110 is used to generate laser light of a specific wavelength (eg, 915 nm or 976 nm). By controlling parameters such as the thickness, doping concentration, and material composition of the epitaxial structure, performance indicators such as the wavelength, threshold current, and output power of the semiconductor laser can be adjusted.

[0037] The front electrode 140 can be a P-type electrode. The front electrode 140 is one of the main channels for current injection. When the semiconductor laser is working, the external power supply injects current into the semiconductor laser through the front electrode. The current flows into the quantum well active layer 115 through the ohmic contact layer 118 and other structures, providing the necessary carriers for the recombination of electrons and holes in the quantum well active layer 115, thereby realizing stimulated radiation to generate lasers.

[0038] The back electrode 120 can be an N-type electrode. The back electrode 120 and the front electrode 140 together form a complete current loop. When the front electrode 140 injects current into the semiconductor laser, the current returns to the external power supply through the back electrode 120, forming a closed circuit to ensure the continuous flow of current.

[0039] The insulating layer 130 is used to prevent current injection. The insulating layer 130 can be silicon dioxide (SiO2) or silicon nitride (SiN x ) or its composite film layer, the thickness of the insulating layer 130 can be 100nm to 300nm, that is, the thickness of the insulating layer 130 can be any value between 100nm and 300nm, for example, the thickness of the insulating layer 130 can be 100nm, 120nm, 180nm, 200nm, 240nm or 300nm, etc.

[0040] like Figure 1 and Figure 2As shown, a first current injection window 151 is etched on one side of the epitaxial structure 110 close to the ohmic contact layer 118, and the etching end point of the first current injection window 151 is the ohmic contact layer 118. A plurality of current injection suppression structures are arranged at an edge area of ​​the first current injection window 151, and the plurality of current injection suppression structures are arranged at intervals along a first direction, and the first direction is a direction from the front cavity surface to the rear cavity surface.

[0041] Specifically, the epitaxial structure 110 provided by the present invention has two configuration modes. The first epitaxial structure can be as follows: Figure 3 As shown, the ohmic contact layer 118 is directly composed of a layer of highly doped semiconductor material (such as gallium arsenide (GaAs)); the second epitaxial structure can be as follows Figure 4 As shown, the ohmic contact layer 118 may be composed of a lower ohmic contact layer 1181 , a resistance control layer 1182 , and an upper ohmic contact layer 1183 stacked from bottom to top.

[0042] Different epitaxial structures have different configurations of the current injection suppression structure. The current injection suppression structure corresponding to the first epitaxial structure will be described in detail below with reference to the accompanying drawings.

[0043] like Figure 1 , Figure 3 and Figure 5 As shown, the current injection suppression structure can be a first non-current injection window 152 formed after the insulating layer 130 is grown on the surface of the side of the ohmic contact layer 118 away from the upper limiting layer 117, and the current injection suppression structure can also be a second non-current injection window 153 formed by etching the side of the epitaxial structure 110 close to the ohmic contact layer 118.

[0044] In this implementation, if Figure 1 As shown, the end point of etching of the first current injection window 151 stops at the heavily doped ohmic contact layer 118 to form a good ohmic contact with the P-side electrode (i.e., the front electrode 140), and the thickness of the remaining ohmic contact layer after etching can be 200nm to 500nm, for example, the thickness of the remaining ohmic contact layer after etching can be 200nm, 240nm, 300nm, 360nm, 400nm, 480nm or 500nm, etc. The first non-current injection window 152 includes a complete epitaxial structure 110, and the insulating layer 130 grown on the first non-current injection window 152 can prevent current injection.

[0045] Furthermore, if Figure 1 As shown, the end point of etching the second non-current injection window 153 is the upper limiting layer 117 , the insulating layer 130 is also formed on the second non-current injection window 153 , and the front electrode 140 is also formed on the side surface of the insulating layer 130 away from the second non-current injection window 153 .

[0046] After the heavily doped epitaxial part is etched by the second non-current injection window 153, an insulating layer 130 is grown in the second non-current injection window 153, which can further prevent the current from extending laterally through the heavily doped ohmic contact layer 118 under the insulating layer 130 and causing current leakage.

[0047] Specifically, Figure 5 As shown, the direction indicated by the arrow is the light-emitting surface of the semiconductor laser 100, which is called the front cavity surface. The other surface opposite to the front cavity surface is the back cavity surface. A plurality of current injection suppression structures (in this embodiment, the first non-current injection window 152 and / or the second non-current injection window 153) are arranged at intervals in the edge area of ​​the first current injection window 151 along the direction from the front cavity surface to the back cavity surface (i.e., the first direction). That is, an array of the first non-current injection windows 152 or an array of the second non-current injection windows 153 are formed at the edge of the horizontal direction of the area where the first current injection window 151 is located, or a part of the plurality of current injection suppression structures may be the first non-current injection window 152, and the other part may be the second non-current injection window 153. Among them, when injecting a large current, the current path of the first current injection window 151 can be as follows: Figure 1 As shown by the arrow under the first current injection window 151.

[0048] An insulating layer 130 is grown on the array graphic area (i.e., multiple first non-current injection windows 152 and / or multiple second non-current injection windows 153), and current cannot be injected, thereby forming an equivalent channel with higher resistance at the edge of the first current injection window 151. When a large current is injected, the high resistance means that additional heat will be generated, which reduces the temperature difference between the edge area and the central area, offsetting the effect of the thermal lens, thereby reducing the horizontal far-field divergence angle.

[0049] In this embodiment, the doping concentration of the ohmic contact layer 118 is 2E19 cm -3 To 1E20cm -3 For example, the doping concentration of the ohmic contact layer 118 may be 2E19 cm -3 、3E19cm -3 、6E19cm -3 、8E19cm -3 or 1E20cm -3 wait.

[0050] It should be understood that the higher the doping concentration of the ohmic contact layer 118 under the first current injection window 151, the lower the resistance; the higher the doping concentration of the ohmic contact layer 118 under the first non-current injection window 152, a portion of the current can be laterally extended through the highly doped ohmic contact layer 118, and the first non-current injection window 152 retains the complete ohmic contact layer 118, and has a higher resistance than the first current injection window 151 that retains part of the ohmic contact layer 118. In addition, the resistance of the first non-current injection window 152 is greater than the resistance of the second non-current injection window 153, because there is no ohmic contact layer 118 under the second non-current injection window 153, and there is no highly doped part in the upper limiting layer, so the effect of limiting current is the best.

[0051] The doping concentration of the ohmic contact layer 118 is controlled at 2E19 cm -3 To 1E20cm -3 This can ensure that a good ohmic contact is formed when the P-side electrode (ie, the front electrode 140) is subsequently manufactured.

[0052] Exemplarily, the thickness of the ohmic contact layer 118 may be 200 nm to 800 nm. That is, the thickness of the ohmic contact layer 118 may be any value between 200 nm and 800 nm, for example, the thickness of the ohmic contact layer 118 may be 200 nm, 300 nm, 400 nm, 480 nm, 600 nm, 720 nm or 800 nm.

[0053] Specifically, Figure 5 As shown, the semiconductor laser 100 further includes a heavily doped boss 160 and a strip isolation groove 170. The heavily doped boss 160 can limit the current expansion and ensure that the current is concentrated in the required area. The structure of the heavily doped boss 160 can be consistent with the structure of the first non-current injection window 152. The strip isolation groove 170 can define the current injection and limit the light field in the central area. The structure of the strip isolation groove 170 can be the same as the structure of the second non-current injection window 153.

[0054] The present invention does not specifically limit the shape, size and distribution position of the first non-current injection window 152 and the second non-current injection window 153. Figure 6 As shown, the shapes of the first non-current injection window 152 and the second non-current injection window 153 can be an isosceles trapezoid, an isosceles triangle, a rectangle or other shapes. Figure 5 For example, the current injection suppression structure is the first non-current injection window 152 , and the shape of the first non-current injection window 152 is an isosceles trapezoid, but the present invention is not limited thereto.

[0055] Alternatively, if Figure 6As shown, the width L1 of the first non-current injection window 152 and / or the second non-current injection window 153 (i.e., the current injection suppression structure) can be 20μm to 60μm, i.e., L1=20μm~60μm. For example, L1 can be 20μm, 30μm, 36μm, 40μm, 50μm or 60μm, etc.

[0056] Specifically, when the shape of the first non-current injection window 152 (and / or the second non-current injection window 153) is an isosceles trapezoid, the width L1 of the first non-current injection window 152 (and / or the second non-current injection window 153) may refer to the upper base of the isosceles trapezoid, and the width L2 of the lower base of the isosceles trapezoid may be 5μm to 20μm, that is, L2=5μm~20μm, for example, L2 may be 5μm, 8μm, 10μm, 12μm, 15μm or 20μm, etc. When the shape of the first non-current injection window 152 (and / or the second non-current injection window 153) is an isosceles triangle, the width L1 of the first non-current injection window 152 (and / or the second non-current injection window 153) may refer to the base of the isosceles triangle; when the shape of the first non-current injection window 152 (and / or the second non-current injection window 153) is a rectangle, the width L1 of the first non-current injection window 152 (and / or the second non-current injection window 153) may refer to the length of the rectangle in the first direction.

[0057] like Figure 6 As shown, when the shape of the current injection suppression structure is an isosceles trapezoid or an isosceles triangle, the base angle θ of the shape of the first non-current injection window 152 (and / or the second non-current injection window 153) can be 30° to 60°, that is, θ=30°~60°, for example, θ can be 30°, 45° or 60°, etc.

[0058] Exemplarily, the spacing between two adjacent first non-current injection windows 152 (and / or second non-current injection windows 153) in the first direction may be 10 μm to 200 μm, for example, the spacing between two adjacent first non-current injection windows 152 (and / or second non-current injection windows 153) in the first direction may be 10 μm, 40 μm, 80 μm, 100 μm, 120 μm or 200 μm, etc. Moreover, the ratio of the first spacing Sn to the second spacing Sn+1 may be 0.5:1 to 2:1, that is, Sn:Sn+1=0.5:1~2:1, for example, Sn:Sn+1 may be 0.5:1, 1:1 or 2:1, etc.

[0059] Among them, the first spacing is the spacing between the first suppression current injection structure and the second suppression current injection structure among three adjacent suppression current injection structures (in this embodiment, the first non-current injection window 152 and / or the second non-current injection window 153) in the first direction, and the second spacing is the spacing between the second suppression current injection structure and the third suppression current injection structure among the three adjacent suppression current injection structures in the first direction.

[0060] For example, Figure 5 As shown, the spacing S1 between the first first non-current injection window 152 (and / or the second non-current injection window 153) and the second first non-current injection window 152 (and / or the second non-current injection window 153) is 10μm, Sn:Sn+1=0.5:1, at this time, the spacing S2 between the second first non-current injection window 152 (and / or the second non-current injection window 153) and the third first non-current injection window 152 (and / or the second non-current injection window 153) can be 20μm, and the spacing S3 between the third first non-current injection window 152 (and / or the second non-current injection window 153) and the fourth first non-current injection window 152 (and / or the second non-current injection window 153) can be 40μm.

[0061] That is to say, in the direction from the front cavity surface to the rear cavity surface, the spacing between the multiple first non-current injection windows 152 (and / or the second non-current injection windows 153) can be equidistant, or can gradually increase (or gradually decrease), the array pattern density can change from dense to sparse (or from sparse to dense), and the spacing between the multiple first non-current injection windows 152 (and / or the second non-current injection windows 153) can be adjusted based on the light intensity distribution in the first direction.

[0062] In this embodiment, the light intensity distribution in the direction from the front cavity surface to the rear cavity surface may be inconsistent. By controlling the spacing between the multiple first non-current injection windows 152 (and / or the second non-current injection windows 153), the current injection efficiency can be adjusted while effectively reducing the horizontal far-field divergence angle, thereby improving the light output power of the semiconductor laser.

[0063] For example, Figure 5 As shown, the spacing d between the current injection suppression structure closest to the rear cavity surface and the edge of the first current injection window 151 in the first direction can be 5μm to 100μm, that is, d=5μm~100μm, for example, d can be 5μm, 10μm, 20μm, 30μm, 48μm, 60μm, 80μm, 96μm or 100μm, etc. The spacing between the current injection suppression structure closest to the front cavity surface and the first current injection window 151 in the first direction can also be 5μm to 100μm.

[0064] like Figure 5 and Figure 6 As shown, the ratio of the height H1 of the current injection suppression structure to the height H2 of the first current injection window can be 1:2 to 1:20, that is, H1:H2=1:2~1:20, for example, H1:H2 can be 1:2, 1:4, 1:10, 1:12, 1:16 or 1:20, etc.

[0065] In some optional embodiments, such as Figure 7 As shown, the heights of the multiple current injection suppression structures vary gradually along the first direction. Figure 5 , the heights of the plurality of first non-current injection windows 152 in this embodiment gradually increase (or decrease).

[0066] Alternatively, if Figure 7 As shown, the ratio of the height H3 of the current injection suppression structure closest to the front cavity surface to the height H4 of the current injection suppression structure closest to the rear cavity surface is 1:1 to 1:10, that is, H3:H4=1:1~1:10, for example, H3:H4 can be 1:1, 1:2, 1:6, 1:9 or 1:10, etc.

[0067] In this embodiment, the heights of the multiple current injection suppression structures vary gradually along the first direction, which can effectively reduce the horizontal far-field divergence angle while increasing the output power of the semiconductor laser.

[0068] In some other optional embodiments, Figure 8 As shown, multiple current injection suppression structures are arranged in a preset area near the rear cavity surface. The preset area can be determined by the designer based on the requirements. For example, the area where the first current injection window 151 is located can be divided into two. Figure 5 In this embodiment, the plurality of first non-current injection windows 152 (and / or second non-current injection windows 153) are arranged in the right half region close to the rear cavity surface.

[0069] Alternatively, if Figure 8 As shown, the ratio of the length L4 of the area where the current injection suppression structure is set in the first direction to the length L0 of the first current injection window 151 in the first direction can be 1:1 to 1:10, that is, L4:L0=1:1~1:10, for example, L4:L0 can be 1:1, 1:3, 1:6, 1:8 or 1:10, etc.

[0070] Furthermore, if Fig. 9 As shown, the heights of multiple current injection suppression structures arranged in a preset area near the rear cavity surface also vary gradiently along the first direction, and the ratio of the height H3 of the current injection suppression structure closest to the front cavity surface to the height H4 of the current injection suppression structure closest to the rear cavity surface can also be 1:1 to 1:10.

[0071] Next, in conjunction with the accompanying drawings, the current injection suppression structure corresponding to the second epitaxial structure is described in detail.

[0072] like Figure 2 , Figure 4 and Fig.10 As shown, the ohmic contact layer 118 includes a lower ohmic contact layer 1181, a resistance control layer 1182 and an upper ohmic contact layer 1183 stacked from bottom to top, the etching end point of the first current injection window 151 is the lower ohmic contact layer 1181, the current injection suppression structure can be a second current injection window 154 formed by etching the upper ohmic contact layer 1183, and the etching end point of the second current injection window 154 is the upper ohmic contact layer 1183.

[0073] In this embodiment, if Figure 2 As shown, the end point of etching of the first current injection window 151 stops at the heavily doped lower ohmic contact layer 1181 to form a good ohmic contact with the P-side electrode (i.e., the front electrode 140), and the thickness of the remaining lower ohmic contact layer after etching can be 200nm to 500nm, for example, the thickness of the remaining lower ohmic contact layer after etching can be 200nm, 240nm, 300nm, 360nm, 400nm, 480nm or 500nm, etc. The end point of etching of the second current injection window 154 stops at the heavily doped upper ohmic contact layer 1183, and the thickness of the remaining upper ohmic contact layer after etching can also be 200nm to 500nm.

[0074] Furthermore, if Figure 2 As shown, the epitaxial structure 110 is further etched to form a third non-current injection window 155 and a fourth non-current injection window 156 at one end close to the upper ohmic contact layer 1183. The end point of etching the third non-current injection window 155 is the upper limiting layer 117, the insulating layer 130 is also formed on the third non-current injection window 155, and the front electrode 140 is also formed on the side surface of the insulating layer 130 away from the third non-current injection window 155; the fourth non-current injection window 156 is formed after the insulating layer 130 is grown on the side surface of the upper ohmic contact layer 1183 away from the resistance control layer 1182. At this time, the current injection suppression structure can also be the third non-current injection window 155 and / or the fourth non-current injection window 156.

[0075] That is, the current injection suppression structure may be the second current injection window 154, the third non-current injection window 155 or the fourth non-current injection window 156, and the multiple current injection suppression structures may include at least one of the second current injection window 154, the third non-current injection window 155 and the fourth non-current injection window 156. For example, the multiple current injection suppression structures may all be the second current injection window 154, the third non-current injection window 155 or the fourth non-current injection window 156, and the multiple current injection suppression structures may also have the second current injection window 154 as the first part, the third non-current injection window 155 as the second part and the fourth non-current injection window 156 as the third part.

[0076] The third non-current injection window 155 also etches a portion of the highly doped upper confinement layer, which is suitable for the strip isolation groove area to further prevent the current from extending laterally through the heavily doped upper confinement layer 117 under the insulating layer 130, causing current leakage and reducing laser efficiency.

[0077] Specifically, Fig.10 As shown, the direction indicated by the arrow is the light-emitting surface of the semiconductor laser 100, which is called the front cavity surface. The other surface opposite to the front cavity surface is the back cavity surface. A plurality of current injection suppression structures (in this embodiment, the second current injection window 154, the third non-current injection window 155 and / or the fourth non-current injection window 156) are arranged at intervals in the edge area of ​​the first current injection window 151 along the direction from the front cavity surface to the back cavity surface (i.e., the first direction). That is, an array of the second current injection window 154, the third non-current injection window 155 and / or the fourth non-current injection window 156 is formed at the edge of the horizontal direction of the area where the first current injection window 151 is located. Among them, when injecting a large current, the current path of the first current injection window 151 can be as follows Figure 2 As shown by the arrow under the first current injection window 151, the current path of the second current injection window 154 can be as follows Figure 2 As shown by the arrow under the second current injection window 154.

[0078] In this embodiment, compared with the first current injection window 151, the path through which the current flows in the current injection suppression structure (the second current injection window 154, the third non-current injection window 155 and / or the fourth non-current injection window 156) includes a resistance control layer 1182 with a higher resistance value. When a large current is injected, the high resistance value means that additional heat will be generated, which reduces the temperature difference between the edge area and the central area, offsets the effect of the thermal lens, and thus reduces the horizontal far-field divergence angle.

[0079] In this embodiment, the doping concentration of the upper ohmic contact layer 1183 and the lower ohmic contact layer 1181 can be 2E19cm -3 To 1E20cm-3 The doping concentration of the resistance control layer 1182 may be 1E17 cm -3 To 1E20cm -3 For example, the doping concentrations of the upper ohmic contact layer 1183 and the lower ohmic contact layer 1181 can both be 2E19 cm -3 、3E19cm -3 、6E19cm -3 、8E19cm -3 or 1E20cm -3 The doping concentration of the resistance control layer 1182 may be 1E17cm -3 、1E18cm -3 、1E19cm -3 or 1E20cm -3 wait.

[0080] The doping concentration of the upper ohmic contact layer 1183 and the lower ohmic contact layer 1181 is controlled at 2E19 cm -3 To 1E20cm -3 This can ensure that a good ohmic contact is formed when the P-side electrode (ie, the front electrode 140) is subsequently manufactured.

[0081] Exemplarily, the thickness of the upper ohmic contact layer 1183 and the lower ohmic contact layer 1181 can be 200nm to 800nm. That is, the thickness of the upper ohmic contact layer 1183 and the lower ohmic contact layer 1181 can be any value between 200nm and 800nm, for example, the thickness of the upper ohmic contact layer 1183 and the lower ohmic contact layer 1181 can be 200nm, 300nm, 400nm, 480nm, 600nm, 720nm or 800nm, etc.

[0082] The present invention does not specifically limit the shape, size and specific distribution position of the second current injection window 154, the third non-current injection window 155 and / or the fourth non-current injection window 156. For example, the shape of the second current injection window 154, the third non-current injection window 155 and / or the fourth non-current injection window 156 may also be as follows: Figure 6 The isosceles trapezoid, isosceles triangle, rectangle or other shapes shown. Fig.10 For example, the current injection suppression structure is the second current injection window 154 , and the shape of the second current injection window 154 is an isosceles trapezoid, but the present invention is not limited thereto.

[0083] The following takes the current injection suppression structure as the second current injection window 154 as an example to illustrate the size and distribution position of the current injection suppression structure in this embodiment. It should be understood that when the current injection suppression structure is the third non-current injection window 155 and / or the fourth non-current injection window 156, the size and distribution position of the current injection suppression structure may remain unchanged.

[0084] The size of the second current injection window 154 can be the same as that of the first non-current injection window 152, and the distribution of the second current injection window 154 can also be the same as that of the first non-current injection window 152, for example, Fig.10 As shown, the interval between two adjacent second current injection windows 154 in the first direction may also be 10 μm to 200 μm, Sn:Sn+1 may also be 0.5:1-2:1, d may also be 5 μm to 100 μm, and H1:H2 may also be 1:2-1:20.

[0085] In some optional embodiments, such as Fig.11 As shown, the heights of the plurality of current injection suppression structures (in this embodiment, the second current injection windows 154) vary gradually along the first direction. Specifically, compared to Fig.10 In this embodiment, the heights of the plurality of second current injection windows 154 gradually increase (or decrease). For example, the heights of two adjacent second current injection windows 154 may also be the same.

[0086] In this embodiment, the heights of the plurality of second current injection windows 154 vary gradually along the first direction, which can effectively reduce the horizontal far-field divergence angle while increasing the output power of the semiconductor laser.

[0087] Alternatively, if Fig.11 As shown, the ratio of the height H3 of the current injection suppression structure closest to the front cavity surface to the height H4 of the current injection suppression structure closest to the rear cavity surface can also be 1:1 to 1:10, that is, H3:H4=1:1~1:10, for example, H3:H4 can be 1:1, 1:2, 1:6, 1:9 or 1:10, etc.

[0088] In some other optional embodiments, Fig.12 As shown, multiple current injection suppression structures (in this embodiment, the second current injection window 154) are arranged in a preset area close to the rear cavity surface. The preset area can be determined by the designer based on the requirements. For example, the area where the first current injection window 151 is located can be divided into two. Fig.10 In this embodiment, the plurality of second current injection windows 154 are disposed in the right half region close to the rear cavity surface.

[0089] Optionally, the ratio of the length L4 of the area where the current injection suppression structure is set in the first direction to the length L0 of the first current injection window 151 in the first direction can be 1:1 to 1:10, that is, L4:L0=1:1~1:10, for example, L4:L0 can be 1:1, 1:3, 1:6, 1:8 or 1:10, etc.

[0090] Furthermore, if Fig.13 As shown, the heights of multiple current injection suppression structures arranged in a preset area near the rear cavity surface also vary gradiently along the first direction, and the ratio of the height H3 of the current injection suppression structure closest to the front cavity surface to the height H4 of the current injection suppression structure closest to the rear cavity surface can also be 1:1 to 1:10.

[0091] Because when the semiconductor laser works under a large driving current, the interaction between the carriers injected in the center area and the light field is stronger than that in the edge area, so the carrier consumption in the center area is faster than that in the edge area. The extra carriers in the edge area will leak to the non-current injection area at the edge of the chip, or reduce the electro-optical conversion efficiency of the semiconductor laser by non-radiative recombination methods such as spontaneous radiation and injection into deep energy level defect recombination centers. Therefore, the above-mentioned current injection suppression structure (resistance control layer or insulation layer for suppressing current injection) in the edge area is conducive to improving the efficiency of high-power semiconductor lasers and improving reliability to a certain extent.

[0092] In addition, when the front electrode is flipped down on the heat sink, since the quantum well active layer 115 of the second current injection window 154 is farther away from the solder and the heat sink and the heat dissipation path is longer, the heat generated in the edge area of ​​the second current injection window 154 is more difficult to be conducted away through the heat sink, thereby making the heat distribution in the edge area and the central area more balanced, and can effectively suppress the thermal lens effect, thereby reducing the far-field horizontal divergence angle to a certain extent, and improving the device performance and reliability.

[0093] The embodiment of the present invention further provides a method for preparing a semiconductor laser, which includes but is not limited to steps S101 to S106: Step S101, providing a substrate.

[0094] Specifically, the substrate provides physical support for the epitaxial structure of the semiconductor laser and is the basis for the subsequent growth of each layer. A suitable substrate can better maintain the integrity and consistency of the crystal during the growth of the epitaxial layer and reduce the generation of defects. For example, the material of the substrate can be gallium arsenide (GaAs) or indium phosphide (InP).

[0095] Step S102, a buffer layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and an ohmic contact layer are sequentially grown on one surface of the substrate to form an epitaxial structure.

[0096] For example, a buffer layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and an ohmic contact layer can be sequentially grown on one side of the substrate by a molecular beam epitaxy process or a chemical vapor deposition process to form Figure 3 or Figure 4 The epitaxial structure shown.

[0097] Specifically, the buffer layer is used to relieve the lattice mismatch stress between the substrate and the subsequent growth layer, and the confinement layer (upper confinement layer and lower confinement layer) is used to confine the light field to the waveguide layer to prevent the light field from extending to the highly doped confinement layer, causing free carrier absorption loss and reducing the efficiency of the semiconductor laser. At the same time, the highly doped confinement layer can reduce the series resistance of the semiconductor laser and improve the electro-optical conversion efficiency.

[0098] The quantum well active layer is the core area of ​​semiconductor lasers that generates lasers. In the quantum well structure, carriers (electrons and holes) are confined in a very thin space, forming a discrete energy level structure. When current is injected, electrons and holes recombine in the quantum well, releasing photons, realizing the stimulated radiation process and generating lasers.

[0099] The refractive index of the waveguide layer (upper waveguide layer and lower waveguide layer) is between that of the confinement layer and the quantum well active layer. The difference in refractive index forms an optical waveguide structure, which limits the light field generated by the quantum well active layer to propagate within a certain area, reduces light scattering and loss, improves light propagation efficiency, ensures that the laser can be transmitted in a specific direction, and maintains good beam quality during propagation.

[0100] The ohmic contact layer is used to provide a low-resistance ohmic contact between the semiconductor laser and the external circuit, ensuring that current can be smoothly injected into the device while enabling the device to be effectively electrically connected to the external circuit.

[0101] Step S103 , growing a conductive material on a surface of the substrate away from the buffer layer to form a back electrode.

[0102] Exemplarily, the conductive material may be gold (Au), germanium (Ge), nickel (Ni), and alloys thereof.

[0103] Step S104: etching the side of the epitaxial structure close to the ohmic contact layer to form a first current injection window.

[0104] Wherein, the etching end point of the first current injection window is the ohmic contact layer.

[0105] Step S105 , forming a plurality of current injection suppression structures at the edge of the first current injection window.

[0106] Specifically, a plurality of current injection suppression structures are arranged at intervals along a first direction, and the first direction is a direction from the front cavity surface to the rear cavity surface.

[0107] Step S106, growing a conductive material on the first current injection window and on the plurality of current injection suppression structures to form a front electrode to prepare a semiconductor laser.

[0108] The semiconductor laser is the semiconductor laser provided by any of the above embodiments, and the material of the front electrode can be titanium (Ti), platinum (Pt), gold (Au) and alloys thereof.

[0109] The semiconductor laser prepared by the semiconductor laser preparation method provided in this embodiment forms multiple current injection suppression structures at the edge of the first current injection window, which can not only offset the thermal lens effect and reduce the far-field horizontal divergence angle, but also make the temperature distribution uniform and improve the reliability of the semiconductor laser. At the same time, by regulating the carrier injection, the light field distribution and the carrier distribution in the center and edge areas can be adapted to achieve higher electro-optical conversion efficiency.

[0110] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0111] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0112] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0113] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0114] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the present invention.

Claims

1. A semiconductor laser, characterized in that: The semiconductor laser comprises: The epitaxial structure includes a substrate, a buffer layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and an ohmic contact layer stacked from bottom to top; A back electrode is formed on a surface of the substrate away from the buffer layer; A first current injection window is formed by etching a side of the epitaxial structure close to the ohmic contact layer, the end point of etching the first current injection window is the ohmic contact layer, and a plurality of current injection suppression structures are arranged at intervals along a first direction in the edge area of ​​the first current injection window, and the first direction is the direction from the front cavity surface to the rear cavity surface; A front electrode is formed on the first current injection window and the plurality of current injection suppression structures.

2. The semiconductor laser according to claim 1, characterized in that The current injection suppression structure is a first non-current injection window formed after an insulating layer is grown on a surface of the ohmic contact layer at a side away from the upper confinement layer.

3. The semiconductor laser according to claim 1, characterized in that A second non-current injection window is also etched to form a side of the epitaxial structure close to the ohmic contact layer, and the etching end point of the second non-current injection window is the upper limiting layer. An insulating layer is also formed on the second non-current injection window, and the front electrode is also formed on the surface of the side of the insulating layer away from the second non-current injection window. The current injection suppression structure is the second non-current injection window.

4. The semiconductor laser according to claim 3, characterized in that The thickness of the remaining ohmic contact layer after etching is 200 nm to 500 nm.

5. The semiconductor laser according to claim 1, characterized in that The ohmic contact layer comprises a lower ohmic contact layer, a resistance control layer and an upper ohmic contact layer stacked from bottom to top, and the end point of etching the first current injection window is the lower ohmic contact layer; The current injection suppression structure is a second current injection window formed after etching the upper ohmic contact layer, and the end point of etching the second current injection window is the upper ohmic contact layer.

6. The semiconductor laser according to claim 1, characterized in that The ohmic contact layer comprises a lower ohmic contact layer, a resistance control layer and an upper ohmic contact layer stacked from bottom to top, the end point of etching the first current injection window is the lower ohmic contact layer, and the end of the epitaxial structure close to the upper ohmic contact layer is further etched to form a third non-current injection window and a fourth non-current injection window; The end point of etching the third non-current injection window is the upper limiting layer, an insulating layer is formed on the third non-current injection window, and the front electrode is also formed on a surface of the insulating layer away from the third non-current injection window; The fourth non-current injection window is formed after an insulating layer is grown on the surface of the upper ohmic contact layer away from the resistance control layer, and the current injection suppression structure is the third non-current injection window and / or the fourth non-current injection window.

7. The semiconductor laser according to claim 6, characterized in that The doping concentrations of the upper ohmic contact layer and the lower ohmic contact layer are both 2E19cm -3 To 1E20cm -3 The doping concentration of the resistance control layer is 1E17cm -3 To 1E20cm -3 .

8. The semiconductor laser according to claim 1, characterized in that The distance between the current injection suppression structure closest to the rear cavity surface and the edge of the first current injection window in the first direction is 5 μm to 100 μm.

9. The semiconductor laser according to any one of claims 1 to 8, characterized in that The spacing between two adjacent current injection suppression structures in the first direction is 10μm to 200μm, and the ratio of the first spacing to the second spacing is 0.5:1 to 2:

1. The first spacing is the spacing between the first suppression current injection structure and the second suppression current injection structure among the three adjacent current injection suppression structures in the first direction, and the second spacing is the spacing between the second suppression current injection structure and the third suppression current injection structure among the three adjacent current injection suppression structures in the first direction.

10. The semiconductor laser according to any one of claims 1 to 8, characterized in that: A ratio of a height of the current injection suppression structure to a height of the first current injection window is 1:2 to 1:

20.

11. The semiconductor laser according to any one of claims 1 to 8, characterized in that: The heights of the plurality of current injection suppression structures vary gradually along the first direction.

12. The semiconductor laser according to any one of claims 1 to 8, characterized in that: The ratio of the height of the current injection suppression structure closest to the front cavity surface to the height of the current injection suppression structure closest to the rear cavity surface is 1:1 to 1:

10.

13. The semiconductor laser according to claim 12, characterized in that The multiple current injection suppression structures are arranged in a preset area close to the rear cavity surface, and the ratio of the length of the area of ​​the current injection suppression structure in the first direction to the length of the first current injection window in the first direction is set to be 1:1 to 1:

10.

14. The semiconductor laser according to claim 13, characterized in that The shape of the current injection suppression structure is an isosceles trapezoid, an isosceles triangle or a rectangle.

15. The semiconductor laser according to claim 14, characterized in that The width of the current injection suppression structure is 20 μm to 60 μm. When the shape of the current injection suppression structure is an isosceles trapezoid or an isosceles triangle, the base angle of the shape of the current injection suppression structure is 30° to 60°.

16. A method for preparing a semiconductor laser, characterized in that: The method comprises: providing a substrate; A buffer layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and an ohmic contact layer are sequentially grown on a surface of one side of the substrate to form an epitaxial structure; Growing a conductive material on a surface of the substrate away from the buffer layer to form a back electrode; Etching a side of the epitaxial structure close to the ohmic contact layer to form a first current injection window, wherein an end point of etching the first current injection window is the ohmic contact layer; A plurality of current injection suppression structures are formed at the edge of the first current injection window, wherein the plurality of current injection suppression structures are arranged at intervals along a first direction, wherein the first direction is a direction from the front cavity surface to the rear cavity surface; A conductive material is grown on the first current injection window and the plurality of current injection suppression structures to form a front electrode, so as to prepare the semiconductor laser according to any one of claims 1 to 15.

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