Edge-emitting semiconductor laser and manufacturing method thereof

Abstract

The invention discloses an edge-emitting semiconductor laser and a manufacturing method thereof, and the laser comprises a substrate which is provided with a first surface and a second surface which are opposite to each other; the epitaxial structure is formed on the first surface of the substrate, the side, away from the substrate, of the epitaxial structure is constructed into a ridge-shaped structure, the ridge-shaped structure comprises a plurality of ridge-shaped units which are periodically arranged in the first direction and have a preset geometrical shape, and each side face of the ridge-shaped units is parallel to the crystal face of the semiconductor material forming the ridge-shaped structure; the plurality of ridge-shaped units are arranged in an overlapping manner or in a tangent manner or in a spaced manner; the passivation layer is formed on the surface, away from the substrate, of the epitaxial structure, and a window area is arranged on the top of the ridge structure on the passivation layer; the first electrode is at least formed in the window area and electrically connected with the epitaxial structure; the second electrode is formed on the second surface of the substrate. According to the edge-emitting semiconductor laser and the manufacturing method thereof, self-coupling and directional emission can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of lasers, and in particular relates to an edge-emitting semiconductor laser and a manufacturing method thereof. Background Art

[0002] Semiconductor lasers are widely used due to their small size, high efficiency, and low power consumption. Fabry-Perot cavity (FP cavity) and optical microcavity are two different laser structures. The resonant cavity of the FP cavity laser is composed of a pair of parallel mirrors. It has a simple structure, is easy to make, and can easily achieve high-power output; the whispering gallery mode is a stable resonant mode that is confined in the optical microcavity due to total internal reflection of light at the interface. Thanks to the characteristics of high quality factor and small mode volume, the whispering gallery mode microcavity laser has the advantages of low threshold, narrow linewidth and single-mode output.

[0003] In the prior art, due to the characteristics of multi-longitudinal mode oscillation, the output spectrum of the FP cavity laser contains multiple adjacent longitudinal modes, resulting in a wide emission spectrum line width. In order to achieve single-mode output, it is usually necessary to design an additional grating structure to achieve pure mode output, such as introducing a Bragg grating and then making a distributed feedback laser through secondary epitaxy, but this method will greatly increase the complexity of the manufacturing process.

[0004] However, due to the total internal reflection of light in the optical microcavity and the isotropic emission of light caused by rotational symmetry, the light extraction efficiency of optical microcavity lasers is low, making it difficult to achieve high-power output. In order to effectively extract and collect light in the optical microcavity, it is necessary to specially design the structure of direct coupling waveguide or indirect coupling waveguide to achieve directional emission and efficient collection, but this requires high processing precision.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide an edge-emitting semiconductor laser and a manufacturing method thereof, which can realize self-coupling and directional emission.

[0007] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0008] An edge-emitting semiconductor laser comprising:

[0009] A substrate having a first surface and a second surface disposed opposite to each other;

[0010] An epitaxial structure is formed on the first surface of the substrate, wherein the side of the epitaxial structure facing away from the substrate is configured as a ridge structure, wherein the ridge structure comprises a plurality of ridge units which are periodically arranged in a first direction and have a preset geometric shape, wherein each side of the ridge unit is parallel to a crystal plane of a semiconductor material forming the ridge structure, and the plurality of ridge units are arranged in an overlapping manner, a tangential manner, or an interval manner;

[0011] A passivation layer is formed on a surface of the epitaxial structure facing away from the substrate, and a window area is provided on the passivation layer at the top of the ridge structure;

[0012] A first electrode, formed at least in the window region and electrically connected to the epitaxial structure;

[0013] The second electrode is formed on the second surface of the substrate.

[0014] In one or more embodiments of the present invention, the ridge-type unit has a first size L in the first direction, and an arrangement period T of a plurality of the ridge-type units is less than, equal to, or greater than the first size L.

[0015] In one or more embodiments of the present invention, the preset geometric shape of the ridge-type unit includes one of a hexagon, a triangle, and a quadrilateral.

[0016] In one or more embodiments of the present invention, the preset geometric shape of the ridge-type unit is a combination of one or more of a hexagon, a triangle, and a quadrilateral.

[0017] In one or more embodiments of the present invention, the epitaxial structure includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer, and a p-type contact layer sequentially arranged in a direction away from the substrate;

[0018] The thickness of the ridge structure is less than the sum of the thicknesses of the p-type confinement layer and the p-type contact layer; or, the thickness of the ridge structure is greater than the sum of the thicknesses of the p-type confinement layer and the p-type contact layer and less than the sum of the thicknesses of the epitaxial structure and the substrate.

[0019] In one or more embodiments of the present invention, the edge-emitting semiconductor laser has a first end face for emitting light and a second end face arranged opposite to the first end face, an anti-reflection film is formed on the first end face, and a high-reflection film is formed on the second end face.

[0020] A method for manufacturing an edge-emitting semiconductor laser, comprising:

[0021] Providing a substrate, the substrate having a first surface and a second surface arranged opposite to each other, and forming an epitaxial layer on the first surface;

[0022] Etching the epitaxial layer to form a ridge structure, wherein the ridge structure includes a plurality of ridge units that are periodically arranged in a first direction and have a preset geometric shape, each side of the ridge unit is parallel to a crystal plane of a semiconductor material forming the ridge structure, and the plurality of ridge units are arranged in an overlapping, tangential, or spaced arrangement;

[0023] forming a passivation layer at least on the peripheral surface of the ridge structure;

[0024] forming a first electrode electrically connected to the ridge structure at least on top of the ridge structure;

[0025] A second electrode is formed on the second surface.

[0026] In one or more embodiments of the present invention, before the step of forming a passivation layer on the peripheral surface of the ridge structure, the method further includes:

[0027] The step of using chemical reagents to remove etching damage on the peripheral surface of the ridge structure.

[0028] In one or more embodiments of the present invention, after the step of forming the second electrode on the second surface, the method further includes:

[0029] The step of heat treating the sample after forming the first electrode and the second electrode to improve the ohmic contact quality.

[0030] In one or more embodiments of the present invention, after the step of forming the second electrode on the second surface, the method further includes:

[0031] Cleavage to form strips;

[0032] forming an anti-reflection film on a first end surface of the bar used for emitting light;

[0033] A high reflection film is formed on a second end surface of the bar that is opposite to the first end surface.

[0034] In one or more embodiments of the present invention, the epitaxial layer includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer, and a p-type contact layer, which are sequentially arranged in a direction away from the substrate;

[0035] Etching the epitaxial layer to form a ridge structure includes: etching from the upper surface of the p-type contact layer to the p-type confinement layer to form the ridge structure; or etching from the upper surface of the p-type contact layer to the n-type confinement layer to form the ridge structure.

[0036] In one or more embodiments of the present invention, the epitaxial layer is etched along a direction parallel to a crystal plane of a semiconductor material forming the epitaxial layer to form the ridge unit.

[0037] In one or more embodiments of the present invention, the preset geometric shape of the ridge unit is determined according to the crystal system type of the semiconductor material forming the epitaxial layer.

[0038] In one or more embodiments of the present invention, the coupling modes of the plurality of ridge-type units are regulated by changing the preset geometric shapes and arrangement period T of the ridge-type units.

[0039] In one or more embodiments of the present invention, the ridge-type unit has a first size L in the first direction, and an arrangement period T of a plurality of the ridge-type units is less than, equal to, or greater than the first size L.

[0040] In one or more embodiments of the present invention, the preset geometric shape of the ridge-type unit includes one of a hexagon, a triangle, and a quadrilateral.

[0041] In one or more embodiments of the present invention, the preset geometric shape of the ridge-type unit is a combination of one or more of a hexagon, a triangle, and a quadrilateral.

[0042] Compared with the prior art, the edge-emitting semiconductor laser of the present invention combines the characteristics of an optical microcavity laser and an FP cavity laser, is composed of multiple optical microcavities (one ridge-type unit constitutes one optical microcavity), and can achieve self-coupling and directional emission.

[0043] The edge-emitting semiconductor laser of the present invention adjusts the preset geometric shape and arrangement period of the ridge-type unit to control the coupling mode, thereby realizing the manufacture of high-quality edge-emitting semiconductor lasers with a simple manufacturing process.

[0044] The manufacturing method of the edge-emitting semiconductor laser of the present invention is compatible with conventional edge-emitting semiconductor lasers, has a simple structure and is easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 is a top view of the edge-emitting semiconductor laser in Example 1 of the present invention;

[0047] Figure 2 is a structural cross-sectional view of an edge-emitting semiconductor laser in Embodiment 1 of the present invention;

[0048] Figure 3 is a side view schematic diagram of an edge-emitting semiconductor laser in Example 1 of the present invention;

[0049] Figure 4 is a process flow chart of a method for manufacturing an edge-emitting semiconductor laser in Embodiment 1 of the present invention;

[0050] Figure 5 is a structural cross-sectional view of an edge-emitting semiconductor laser in Embodiment 2 of the present invention;

[0051] Figure 6 is a top view of an edge-emitting semiconductor laser in Example 3 of the present invention;

[0052] Figure 7 is a top view of an edge-emitting semiconductor laser in Example 4 of the present invention;

[0053] Figure 8 is a top view of an edge-emitting semiconductor laser in Example 5 of the present invention;

[0054] Fig. 9 is a top view of an edge-emitting semiconductor laser in Example 6 of the present invention;

[0055] Fig.10 is a top view of an edge-emitting semiconductor laser in Example 7 of the present invention;

[0056] Fig.11 It is a top view of the edge-emitting semiconductor laser in Example 8 of the present invention. DETAILED DESCRIPTION

[0057] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0058] As mentioned in the background technology, the output spectrum of the FP cavity laser prepared by the prior art contains multiple adjacent longitudinal modes, resulting in a wide emission spectrum line width. However, the light extraction efficiency of the optical microcavity laser is low, and a special design of direct coupling waveguide or indirect coupling waveguide structure is required to achieve directional emission and efficient collection, and the processing precision is high.

[0059] Based on this, the present invention provides an edge-emitting semiconductor laser and a method for manufacturing the same, which combines the characteristics of an optical microcavity laser and an FP cavity laser, and is formed by a periodic arrangement of multiple optical microcavities (one ridge-type unit constitutes one optical microcavity), and can achieve self-coupling and directional emission. And by adjusting the preset geometric shape and arrangement period of the ridge-type unit, the coupling mode can be regulated to achieve the production of high-quality edge-emitting semiconductor lasers, and the production process is simple.

[0060] like Figures 1 to 3 As shown, the edge-emitting semiconductor laser in Embodiment 1 of the present invention includes a substrate 10 , an epitaxial structure, a passivation layer 30 , a first electrode 40 and a second electrode 50 .

[0061] The material of the substrate 10 can be silicon, sapphire, gallium nitride, gallium arsenide, indium phosphide, etc. The substrate 10 has a first surface and a second surface which are arranged opposite to each other.

[0062] The epitaxial structure is formed on the first surface of the substrate 10 and includes an n-type confinement layer 21 , a lower waveguide layer 22 , an active region 23 , an upper waveguide layer 24 , a p-type confinement layer 25 and a p-type contact layer 26 arranged in sequence away from the substrate 10 .

[0063] The side of the epitaxial structure facing away from the substrate 10 is constructed as a ridge structure. The thickness of the ridge structure can be a relatively small value, that is, from the upper surface of the p-type contact layer 26 to close to but not exceeding the lower surface of the p-type confinement layer 25, such as Figure 2 Therefore, the thickness of the ridge structure is less than the sum of the thicknesses of the p-type confinement layer 25 and the p-type contact layer 26 .

[0064] The thickness of the ridge structure can be a relatively large value, that is, from the upper surface of the p-type contact layer 26 to the lower surface of the n-type confinement layer 21, such as Figure 5 Therefore, the thickness of the ridge structure is greater than the sum of the thicknesses of the p-type confinement layer 25 and the p-type contact layer 26 and is less than the sum of the thicknesses of the epitaxial structure and the substrate 10 .

[0065] The ridge structure includes a plurality of ridge units A arranged periodically in a first direction and having a preset geometric shape, and each side surface of the ridge unit A is parallel to the crystal plane of the semiconductor material forming the ridge structure. The first direction is the arrangement direction of the ridge unit A.

[0066] The preset geometric shape of the ridge unit A includes one of a hexagon, a triangle, and a quadrilateral, or the preset geometric shape of the ridge unit is a combination of one or more of a hexagon, a triangle, and a quadrilateral. Preferably, the preset geometric shape can be selected according to the crystal system type of the semiconductor material forming the epitaxial structure. For example, the gallium nitride material selects a hexagonal or triangular geometric shape, and the gallium arsenide material selects a square geometric shape.

[0067] Each ridge unit A has a first size L in a first direction. The arrangement period T of the plurality of ridge units A is less than, equal to, or greater than the first size L. That is, the plurality of ridge units A are arranged overlappingly, tangentially, or at intervals. By changing the preset geometric shape and arrangement period T of the ridge units A, the coupling mode of the plurality of ridge units A can be regulated.

[0068] It is understandable that, since the laser output of the whispering gallery mode still has a light field distribution within the evanescent length of the evanescent wave, for two adjacent ridge units, when the distance between the two ridge units is less than the evanescent length of the evanescent wave, the modes inside the corresponding optical microcavity will affect each other, that is, coupling will occur. Similarly, when two ridge units overlap in geometric structure, the optical mode in the cavity can also be changed due to the destruction of the symmetry of the optical microcavity with the whispering gallery structure.

[0069] Therefore, the optical mode that can eventually stably exist in the optical microcavity array is closely related to the distance between or overlaps between the optical microcavity units, that is, the distance between or overlaps between the ridge units. By changing the geometric structure and periodic distance of the ridge unit arrangement, the mode coupling of the optical microcavity can be regulated.

[0070] The passivation layer 30 is formed on the surface of the epitaxial structure facing away from the substrate 10. The material of the passivation layer 30 can be silicon oxide, aluminum oxide, silicon nitride, etc. A window area is provided on the top of the ridge structure on the passivation layer 30. The window area is formed by ion beam etching, inductively coupled plasma etching, wet etching, etc.

[0071] The first electrode 40 is at least formed in the window region and is electrically connected to the epitaxial structure. The first electrode 40 is preferably a metal electrode, and the first electrode 40 can be manufactured by electron beam evaporation, magnetron sputtering, etc.

[0072] The second electrode 50 is formed on the second surface of the substrate 10. The second electrode 50 is also preferably a metal electrode, and the second electrode 50 can be manufactured by electron beam evaporation, magnetron sputtering, etc.

[0073] like Figure 3 As shown, the edge-emitting semiconductor laser also has a first end face 61 for emitting light and a second end face 62 arranged opposite to the first end face 61. An anti-reflection film 71 is formed on the first end face 61, and a high-reflection film 72 is formed on the second end face 62. The anti-reflection film 71 and the high-reflection film 72 can be a single-layer dielectric material, or a pair of dielectric materials with a refractive index difference. The dielectric material can be silicon oxide, aluminum oxide, titanium oxide, tantalum oxide, hafnium oxide, zirconium oxide, etc.

[0074] like Figure 4As shown, the present invention also provides a method for manufacturing the edge-emitting semiconductor laser in the above-mentioned embodiment 1, which specifically comprises the following steps:

[0075] S1, providing a substrate, wherein the substrate has a first surface and a second surface arranged opposite to each other, and forming an epitaxial layer on the first surface.

[0076] The material of the substrate can be silicon, sapphire, gallium nitride, gallium arsenide, indium phosphide, etc. The grown epitaxial layer material mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer which are sequentially arranged in a direction away from the substrate 10 .

[0077] S2, etching the epitaxial layer to form a ridge structure.

[0078] The etching depth can be a smaller value, that is, the distance from the upper surface of the p-type contact layer to a distance close to but not exceeding the lower surface of the p-type confinement layer; or, the etching depth can be a larger value, that is, the distance from the upper surface of the p-type contact layer to a distance exceeding the lower surface of the n-type confinement layer.

[0079] The ridge structure includes a plurality of ridge units that are periodically arranged in a first direction and have a preset geometric shape, and each side of the ridge unit is parallel to the crystal plane of the semiconductor material forming the ridge structure. The preset geometric shape of the ridge unit A includes one of a hexagon, a triangle, and a quadrilateral, or the preset geometric shape of the ridge unit is a combination of one or more of a hexagon, a triangle, and a quadrilateral. Preferably, the preset geometric shape can be selected according to the crystal system type of the semiconductor material forming the epitaxial structure. For example, a hexagonal or triangular geometric shape is selected for gallium nitride material, and a square geometric shape is selected for gallium arsenide material, etc.

[0080] Each ridge unit A has a first size L in a first direction. The arrangement period T of the plurality of ridge units A is less than, equal to, or greater than the first size L. That is, the plurality of ridge units A are arranged overlappingly, tangentially, or at intervals. By changing the preset geometric shape and arrangement period T of the ridge units A, the coupling mode of the plurality of ridge units A can be regulated.

[0081] S3, using chemical reagents to remove etching damage on the peripheral surface of the ridge structure.

[0082] Exemplarily, the chemical reagent may be potassium hydroxide, tetramethylammonium hydroxide, ammonia water, hydrochloric acid, phosphoric acid, or the like.

[0083] S4, forming a passivation layer at least on the peripheral surface of the ridge structure.

[0084] Preferably, a passivation layer is deposited on the side away from the substrate, and a window area is exposed on the top of the ridge structure by etching. The etching method adopts ion beam etching, inductively coupled plasma etching, wet etching, etc. The passivation layer material can be silicon oxide, aluminum oxide, silicon nitride, etc.

[0085] If the etching depth only reaches the p-type confinement layer, the passivation layer covers the surface of the p-type confinement layer, the peripheral surface of the ridge structure, and extends to part of the top surface of the ridge structure. If the etching depth reaches the substrate, the passivation layer covers the upper surface of the substrate, the peripheral surface of the ridge structure, and extends to part of the top surface of the ridge structure.

[0086] S5, manufacturing a first electrode, and manufacturing a second electrode after thinning the substrate.

[0087] A first electrode electrically connected to the ridge structure is formed at least on the top of the ridge structure, a second electrode is formed on the second surface of the substrate, and a heat treatment is performed on the sample after the first electrode and the second electrode are formed to improve the ohmic contact quality.

[0088] The substrate thinning methods include mechanical grinding, chemical mechanical grinding, chemical mechanical polishing, etc. The electrode production methods can be electron beam evaporation, magnetron sputtering, etc. Among them, the ohmic contact quality can be improved by rapid heat treatment after electrode evaporation.

[0089] S6, based on the above sample, a number of bars are obtained by cleavage, and an anti-reflection film and a high-reflection film are evaporated on the front and rear cleavage surfaces of the bars to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0090] The direction of cleavage is perpendicular to the arrangement direction of the ridge-shaped units. The sample can be cleaved into bars with a pair of parallel crystal planes by equipment such as a laser scribing machine and a Loomis cleaving machine. The cleaved bars have a first end face for emitting light and a second end face arranged opposite to the first end face, an anti-reflection film is formed on the first end face, and a high-reflection film is formed on the second end face. The anti-reflection film and the high-reflection film can be a single layer of dielectric material, or a pair of dielectric materials with a refractive index difference. The dielectric material may include silicon oxide, aluminum oxide, titanium oxide, tantalum oxide, hafnium oxide, zirconium oxide, etc.

[0091] Compared with the prior art, the edge-emitting semiconductor laser of the present invention combines the characteristics of an optical microcavity laser and an FP cavity laser, is composed of multiple optical microcavities (one ridge-type unit constitutes one optical microcavity), and can achieve self-coupling and directional emission.

[0092] The edge-emitting semiconductor laser of the present invention adjusts the preset geometric shape and arrangement period of the ridge-type unit to control the coupling mode, thereby realizing the manufacture of high-quality edge-emitting semiconductor lasers with a simple manufacturing process.

[0093] The manufacturing method of the edge-emitting semiconductor laser of the present invention is compatible with conventional edge-emitting semiconductor lasers, has a simple structure and is easy to manufacture.

[0094] The following describes several specific embodiments to facilitate understanding of the technical solutions of the present invention.

[0095] like Figure 1 As shown, in Example 1, the method for manufacturing an edge-emitting semiconductor laser comprises the following steps:

[0096] The epitaxial layer of the gallium nitride semiconductor laser is grown on a cleaned gallium nitride substrate. The epitaxial layer mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer.

[0097] By photolithography on the GaN semiconductor laser epitaxial wafer, the graphic unit is defined as a hexagonal ridge unit A, and each side of the hexagon is parallel to the GaN crystal. Crystal plane. The arrangement period T1 of the hexagonal ridge unit A is greater than its own size in the arrangement direction. Subsequently, the gallium nitride material on both sides is removed by inductively coupled plasma etching, and the etching depth from the upper surface of the p-type contact layer does not exceed the lower surface of the p-type confinement layer, thereby obtaining the ridge structure of the edge-emitting semiconductor laser.

[0098] The etched gallium nitride sidewalls are treated with a hot tetramethylammonium hydroxide solution to remove etching damage on the material surface caused by dry etching and improve the roughness of the side surface of the ridge structure.

[0099] A layer of silicon oxide is deposited by plasma enhanced chemical vapor deposition, and then the p-type contact layer on the top of the ridge structure is exposed through photolithography and etching processes.

[0100] A metal electrode is deposited on the p-side, and after the wafer is thinned, ground, and polished, a metal electrode is deposited on the n-side.

[0101] The wafer is cleaved into bars along the cleavage plane, and a layer of silicon oxide and a pair of tantalum oxide / silicon oxide dielectric films are deposited on the front and rear surfaces of the bars respectively to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0102] like Figure 6 As shown, in Example 3, the method for manufacturing an edge-emitting semiconductor laser comprises the following steps:

[0103] The epitaxial layer of the gallium nitride semiconductor laser is grown on a cleaned gallium nitride substrate. The epitaxial layer mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer.

[0104] By photolithography on the GaN semiconductor laser epitaxial wafer, the graphic unit is defined as a hexagonal ridge unit A, and each side of the hexagon is parallel to the GaN crystal. Crystal plane. The arrangement period T2 of the hexagonal ridge unit A is equal to its own size in the arrangement direction. Subsequently, the gallium nitride material on both sides is removed by inductively coupled plasma etching, and the etching depth from the upper surface of the p-type contact layer exceeds the lower surface of the n-type confinement layer, thereby obtaining the ridge structure of the edge-emitting semiconductor laser.

[0105] The etched gallium nitride sidewalls are treated with a hot tetramethylammonium hydroxide solution to remove etching damage on the material surface caused by dry etching and improve the roughness of the side surface of the ridge structure.

[0106] A layer of silicon oxide is deposited by plasma enhanced chemical vapor deposition, and then the p-type contact layer on the top of the ridge structure is exposed through photolithography and etching processes.

[0107] A metal electrode is deposited on the p-side, and after the wafer is thinned, ground, and polished, a metal electrode is deposited on the n-side.

[0108] The wafer is cleaved into bars along the cleavage plane, and a layer of silicon oxide and a pair of tantalum oxide / silicon oxide dielectric films are deposited on the front and rear surfaces of the bars respectively to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0109] like Figure 7 As shown, in Example 4, the method for manufacturing an edge-emitting semiconductor laser comprises the following steps:

[0110] The epitaxial layer of the gallium nitride semiconductor laser is grown on a cleaned gallium nitride substrate. The epitaxial layer mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer.

[0111] By photolithography on the GaN semiconductor laser epitaxial wafer, the graphic unit is defined as a hexagonal ridge unit A, and each side of the hexagon is parallel to the GaN crystal. Crystal plane. The arrangement period T3 of the hexagonal ridge unit A is smaller than its own size in the arrangement direction. Subsequently, the gallium nitride material on both sides is removed by inductively coupled plasma etching, and the etching depth from the upper surface of the p-type contact layer exceeds the lower surface of the n-type confinement layer, thereby obtaining the ridge structure of the edge-emitting semiconductor laser.

[0112] The etched gallium nitride sidewalls are treated with a hot tetramethylammonium hydroxide solution to remove etching damage on the material surface caused by dry etching and improve the roughness of the side surface of the ridge structure.

[0113] A layer of silicon oxide is deposited by plasma enhanced chemical vapor deposition, and then the p-type contact layer on the top of the ridge structure is exposed through photolithography and etching processes.

[0114] A metal electrode is deposited on the p-side, and after the wafer is thinned, ground, and polished, a metal electrode is deposited on the n-side.

[0115] The wafer is cleaved into bars along the cleavage plane, and a layer of silicon oxide and a pair of tantalum oxide / silicon oxide dielectric films are deposited on the front and rear surfaces of the bars respectively to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0116] like Figure 8 As shown, in Example 5, the method for manufacturing an edge-emitting semiconductor laser comprises the following steps:

[0117] The epitaxial layer of the gallium nitride semiconductor laser is grown on a cleaned gallium nitride substrate. The epitaxial layer mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer.

[0118] By photolithography on the GaN semiconductor laser epitaxial wafer, the graphic unit is defined as a triangular ridge unit A, and each side of the triangle is parallel to the GaN crystal. Crystal plane. The arrangement period T4 of the triangular ridge unit A is smaller than its own size in the arrangement direction. Subsequently, the gallium nitride material on both sides is removed by inductively coupled plasma etching, and the etching depth from the upper surface of the p-type contact layer does not exceed the lower surface of the p-type confinement layer, thereby obtaining the ridge structure of the edge-emitting semiconductor laser.

[0119] The etched gallium nitride sidewalls are treated with a hot tetramethylammonium hydroxide solution to remove etching damage on the material surface caused by dry etching and improve the roughness of the side surface of the ridge structure.

[0120] A layer of silicon oxide is deposited by plasma enhanced chemical vapor deposition, and then the p-type contact layer on the top of the ridge structure is exposed through photolithography and etching processes.

[0121] A metal electrode is deposited on the p-side, and after the wafer is thinned, ground, and polished, a metal electrode is deposited on the n-side.

[0122] The wafer is cleaved into bars along the cleavage plane, and a layer of silicon oxide and a pair of tantalum oxide / silicon oxide dielectric films are deposited on the front and rear surfaces of the bars respectively to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0123] like Fig. 9 As shown, in Example 6, the method for manufacturing an edge-emitting semiconductor laser comprises the following steps:

[0124] The epitaxial layer of the gallium nitride semiconductor laser is grown on a cleaned gallium nitride substrate. The epitaxial layer mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer.

[0125] By photolithography on the GaN semiconductor laser epitaxial wafer, the graphic unit is defined as a triangular ridge unit A, and each side of the triangle is parallel to the GaN crystal. Crystal plane. The arrangement period T5 of the triangular ridge unit A is smaller than its own size in the arrangement direction, and is symmetrically distributed in two opposite directions. Subsequently, the gallium nitride material on both sides is removed by inductively coupled plasma etching, and the etching depth from the upper surface of the p-type contact layer does not exceed the lower surface of the p-type confinement layer, thereby obtaining the ridge structure of the edge-emitting semiconductor laser.

[0126] The etched gallium nitride sidewalls are treated with a hot tetramethylammonium hydroxide solution to remove etching damage on the material surface caused by dry etching and improve the roughness of the side surface of the ridge structure.

[0127] A layer of silicon oxide is deposited by plasma enhanced chemical vapor deposition, and then the p-type contact layer on the top of the ridge structure is exposed through photolithography and etching processes.

[0128] A metal electrode is deposited on the p-side, and after the wafer is thinned, ground, and polished, a metal electrode is deposited on the n-side.

[0129] The wafer is cleaved into bars along the cleavage plane, and a layer of silicon oxide and a pair of tantalum oxide / silicon oxide dielectric films are deposited on the front and rear surfaces of the bars respectively to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0130] like Fig.10 As shown, in Example 7, the method for manufacturing an edge-emitting semiconductor laser comprises the following steps:

[0131] The epitaxial layer of the gallium nitride semiconductor laser is grown on a cleaned gallium nitride substrate. The epitaxial layer mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer.

[0132] By photolithography on the GaN semiconductor laser epitaxial wafer, the graphic unit is defined as a diamond-shaped ridge unit A, and each side of the diamond is parallel to the GaN crystal. Crystal plane. The arrangement period T6 of the rhombus ridge unit A is smaller than its own size in the arrangement direction. Subsequently, the gallium nitride material on both sides is removed by inductively coupled plasma etching, and the etching depth from the upper surface of the p-type contact layer does not exceed the lower surface of the p-type confinement layer, thereby obtaining the ridge structure of the edge-emitting semiconductor laser.

[0133] The etched gallium nitride sidewalls are treated with a hot tetramethylammonium hydroxide solution to remove etching damage on the material surface caused by dry etching and improve the roughness of the side surface of the ridge structure.

[0134] A layer of silicon oxide is deposited by plasma enhanced chemical vapor deposition, and then the p-type contact layer on the top of the ridge structure is exposed through photolithography and etching processes.

[0135] A metal electrode is deposited on the p-side, and after the wafer is thinned, ground, and polished, a metal electrode is deposited on the n-side.

[0136] The wafer is cleaved into bars along the cleavage plane, and a layer of silicon oxide and a pair of tantalum oxide / silicon oxide dielectric films are deposited on the front and rear surfaces of the bars respectively to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0137] like Fig.11 As shown, in Example 8, the method for manufacturing an edge-emitting semiconductor laser comprises the following steps:

[0138] The epitaxial layer of the gallium arsenide semiconductor laser is grown on a cleaned gallium arsenide substrate. The epitaxial layer mainly includes an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer and a p-type contact layer.

[0139] By photolithography on the GaAs semiconductor laser epitaxial wafer, the graphic unit is defined as a ridge unit A consisting of two squares of different sizes, each side of the square is parallel to the GaAs crystal. { 110 } Crystal plane. The arrangement period T7 of the square ridge unit A is equal to its own size in the arrangement direction. Then, the gallium arsenide material on both sides is removed by inductively coupled plasma etching, and the etching depth from the upper surface of the p-type contact layer exceeds the lower surface of the n-type confinement layer, thereby obtaining the ridge structure of the edge-emitting semiconductor laser.

[0140] The etched gallium arsenide sidewalls are treated with a mixed solution of phosphoric acid and hydrogen peroxide to remove etching damage on the material surface caused by dry etching and improve the roughness of the side surface of the ridge structure.

[0141] A layer of silicon oxide is deposited by plasma enhanced chemical vapor deposition, and then the p-type contact layer on the top of the ridge structure is exposed through photolithography and etching processes.

[0142] A metal electrode is deposited on the p-side, and after the wafer is thinned, ground, and polished, a metal electrode is deposited on the n-side.

[0143] The wafer is cleaved into bars along the cleavage plane, and a layer of silicon oxide and a pair of tantalum oxide / silicon oxide dielectric films are deposited on the front and rear surfaces of the bars respectively to obtain a multi-cavity coupled edge-emitting semiconductor laser.

[0144] Different from the design of conventional sidewall gratings or single optical microcavity, the present invention uses an optical microcavity as a basic unit and regulates the coupling mode by changing the geometric structure and arrangement period of the optical microcavity unit.

[0145] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0146] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An edge-emitting semiconductor laser, characterized in that: include: A substrate having a first surface and a second surface disposed opposite to each other; An epitaxial structure is formed on the first surface of the substrate, wherein the side of the epitaxial structure facing away from the substrate is configured as a ridge structure, wherein the ridge structure comprises a plurality of ridge units which are periodically arranged in a first direction and have a preset geometric shape, wherein each side of the ridge unit is parallel to a crystal plane of a semiconductor material forming the ridge structure, and the plurality of ridge units are arranged in an overlapping manner, a tangential manner, or an interval manner; A passivation layer is formed on a surface of the epitaxial structure facing away from the substrate, and a window area is provided on the passivation layer at the top of the ridge structure; A first electrode, formed at least in the window region and electrically connected to the epitaxial structure; The second electrode is formed on the second surface of the substrate.

2. The edge emitting semiconductor laser according to claim 1, characterized in that: The ridge-type unit has a first size L in the first direction, and an arrangement period T of a plurality of the ridge-type units is less than, equal to, or greater than the first size L.

3. The edge emitting semiconductor laser according to claim 1, characterized in that: The preset geometric shape of the ridge-type unit includes one of a hexagon, a triangle, and a quadrilateral; and / or, The preset geometric shape of the ridge-type unit is composed of one or more combinations of hexagons, triangles, and quadrilaterals.

4. The edge-emitting semiconductor laser according to claim 1, characterized in that: The epitaxial structure comprises an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer, and a p-type contact layer which are sequentially arranged in a direction away from the substrate; The thickness of the ridge structure is less than the sum of the thicknesses of the p-type confinement layer and the p-type contact layer; or, the thickness of the ridge structure is greater than the sum of the thicknesses of the p-type confinement layer and the p-type contact layer and less than the sum of the thicknesses of the epitaxial structure and the substrate.

5. The edge emitting semiconductor laser according to claim 1, characterized in that: The edge-emitting semiconductor laser has a first end face for emitting light and a second end face arranged opposite to the first end face, an anti-reflection film is formed on the first end face, and a high-reflection film is formed on the second end face.

6. A method for manufacturing an edge-emitting semiconductor laser, characterized in that: include: Providing a substrate, the substrate having a first surface and a second surface arranged opposite to each other, and forming an epitaxial layer on the first surface; Etching the epitaxial layer to form a ridge structure, wherein the ridge structure includes a plurality of ridge units that are periodically arranged in a first direction and have a preset geometric shape, each side of the ridge unit is parallel to a crystal plane of a semiconductor material forming the ridge structure, and the plurality of ridge units are arranged in an overlapping, tangential, or spaced arrangement; forming a passivation layer at least on the peripheral surface of the ridge structure; forming a first electrode electrically connected to the ridge structure at least on top of the ridge structure; A second electrode is formed on the second surface.

7. The method for manufacturing an edge-emitting semiconductor laser according to claim 6, characterized in that: Before the step of forming a passivation layer on the peripheral surface of the ridge structure, the method further comprises: A step of using chemical reagents to remove etching damage on the peripheral surface of the ridge structure; and / or, After the step of forming a second electrode on the second surface, the method further comprises: A step of heat treating the sample after forming the first electrode and the second electrode to improve the ohmic contact quality; and / or, After the step of forming a second electrode on the second surface, the method further comprises: Cleavage to form strips; forming an anti-reflection film on a first end surface of the bar used for emitting light; A high reflection film is formed on a second end surface of the bar that is opposite to the first end surface.

8. The method for manufacturing an edge-emitting semiconductor laser according to claim 6, characterized in that: The epitaxial layer comprises an n-type confinement layer, a lower waveguide layer, an active region, an upper waveguide layer, a p-type confinement layer, and a p-type contact layer which are sequentially arranged in a direction away from the substrate; Etching the epitaxial layer to form a ridge structure, comprising: etching from the upper surface of the p-type contact layer to the inside of the p-type confinement layer to form the ridge structure; Alternatively, the ridge structure is formed by etching from the upper surface of the p-type contact layer to the inside of the n-type confinement layer.

9. The method for manufacturing an edge-emitting semiconductor laser according to claim 6, characterized in that: Etching the epitaxial layer in a direction parallel to a crystal plane of a semiconductor material forming the epitaxial layer to form the ridge unit; and / or, Determining a preset geometric shape of the ridge unit according to a crystal system type of a semiconductor material forming the epitaxial layer; and / or, The coupling modes of the plurality of ridge-type units are regulated by changing the preset geometric shape and arrangement period T of the ridge-type units.

10. The method for manufacturing an edge-emitting semiconductor laser according to claim 6, characterized in that: The ridge-type unit has a first size L in the first direction, and an arrangement period T of a plurality of the ridge-type units is less than, equal to, or greater than the first size L; and / or, The preset geometric shape of the ridge-type unit includes one of a hexagon, a triangle, and a quadrilateral; and / or, The preset geometric shape of the ridge-type unit is composed of one or more combinations of hexagons, triangles, and quadrilaterals.

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