Method for producing a semiconductor laser, and semiconductor laser

Abstract

The invention relates to a method for producing at least one semiconductor laser. The method comprises: providing a semiconductor layer sequence having at least one ridge waveguide and a widened region, wherein the main direction of extension of the widened region runs transversely or perpendicularly with respect to the main direction of extension of the ridge waveguide; and forming at least one main structure of the semiconductor laser from the widened region, wherein the main structure is connected to the ridge waveguide and comprises a decoupling facet of the semiconductor laser. The main structure is stepped and / or at least one auxiliary structure is formed from the widened region, which auxiliary structure is laterally spaced from the main structure. The invention also relates to a semiconductor laser.

Description

[0001] Description

[0002] METHOD FOR MANUFACTURING A SEMICONDUCTOR LASER AND SEMICONDUCTOR LASER

[0003] A method for manufacturing a semiconductor laser and a semiconductor laser are described.

[0004] The facets of semiconductor lasers can be generated, for example, by fracturing a sequence of semiconductor layers, thus singulating the semiconductor lasers within the semiconductor laser array. Alternatively, the facets of semiconductor lasers can be generated by etching prior to singulation. Depending on the semiconductor layer sequence or the atomic concentration within the semiconductor layer sequence, etchings can occur in the active region of the semiconductor layer sequence.

[0005] One task to be solved is to specify a method for manufacturing a semiconductor laser that can be produced efficiently. Another task to be solved is to specify an improved semiconductor laser.

[0006] The tasks are solved by the subject matter of the independent claims. Advantageous embodiments and further developments are specified in the dependent claims.

[0007] According to at least one embodiment, the method for manufacturing at least one semiconductor laser comprises providing a sequence of semiconductor layers. The sequence of semiconductor layers may have a first semiconductor layer of a first conduction type and a second semiconductor layer of a second conduction type. For example, the first semiconductor layer is p-doped and the second semiconductor layer is n-doped, or vice versa.

[0008] An active region can be arranged between the first and second semiconductor layers. The active region is configured, for example, to generate electromagnetic radiation, such as radiation in the ultraviolet, visible, or infrared spectral range. The active region can, for example, have a pn junction, a quantum well structure, and / or a multi-quantum well structure. For example, the semiconductor layer sequence includes a II-IV semiconductor material, such as GaN or AlInGaN, or an I-VI semiconductor material.

[0009] The semiconductor layer sequence can have a stacking direction. For example, the first semiconductor layer, the active region, and the second semiconductor layer are arranged consecutively along the stacking direction, for example, directly adjacent to each other.

[0010] The semiconductor layer sequence, for example, has a principal extent plane. The stacking direction of the semiconductor layer sequence can be perpendicular or approximately perpendicular to the principal extent plane of the semiconductor layer sequence.

[0011] The semiconductor layer sequence can be deployed on a support. For example, deploying the semiconductor layer sequence involves the successive growth of the semiconductor layers of the sequence onto a growth substrate. The support can be the growth substrate itself. Alternatively, the support can be, for example, a different substrate than the growth substrate.

[0012] According to at least one embodiment of the method for manufacturing at least one semiconductor laser, the semiconductor layer sequence has at least one bridge waveguide.

[0013] The at least one bridge waveguide can be formed, at least partially, from the semiconductor layer sequence. This bridge waveguide, hereinafter also referred to as the bridge waveguide, can be a protrusion of the semiconductor layer sequence along a vertical direction. This vertical direction runs, for example, parallel to the stacking direction of the semiconductor layer sequence. In other words, the semiconductor layer sequence can have a protrusion, for example, a locally confined protrusion, which can be the bridge waveguide. The protrusion is, for example, located on the side of the semiconductor layer sequence facing away from the substrate.

[0014] The bridge waveguide can have a principal direction of extension. For example, the principal direction of extension of the bridge waveguide runs, at least locally, parallel or approximately parallel to the principal plane of extension of the semiconductor layer sequence. For example, the bridge waveguide is elongated, particularly web-shaped. In a top view of the semiconductor layer sequence, the bridge waveguide can, for example, be at least approximately rectangular. The semiconductor layer sequence can have more than one bridge waveguide. For example, the semiconductor layer sequence has at least two bridge waveguides. The two bridge waveguides can be laterally spaced apart from each other. For example, the at least two bridge waveguides can run parallel or approximately parallel to each other.In other words, the principal orientation of the bridge waveguide can be at least partially parallel or approximately parallel to the principal orientation of another bridge waveguide. For example, the semiconductor layer sequence comprises a plurality of bridge waveguides, such as the bridge waveguide itself and a plurality of other bridge waveguides. The other bridge waveguides can have the same properties as the bridge waveguide, or as the at least one of the bridge waveguides.

[0015] A lateral direction is understood to be a direction that runs parallel to the principal plane of extension of the semiconductor layer sequence. A vertical direction is generally understood to be a direction that is perpendicular to the principal plane of extension of the semiconductor layer sequence. The vertical and lateral directions are perpendicular, approximately orthogonal, to each other.

[0016] According to at least one embodiment of the method for manufacturing at least one semiconductor laser, the semiconductor layer sequence has a broadened region. The broadened region may have a structure, for example, a layer stack, that corresponds completely or at least approximately to the structure of the bridge waveguide. For example, the broadened region is a region of the bridge waveguide in which the bridge waveguide has a greater extent along a direction transverse or perpendicular to the main direction of extent of the bridge waveguide than in regions of the bridge waveguide outside the broadened region. The extent of the bridge waveguide outside the broadened region is, for example, the width of the bridge waveguide. The bridge waveguide may be formed integrally with the broadened region.

[0017] For example, at least two waveguides can have the broadened region. The broadened regions of the waveguides can then be, for example, connected to each other or spaced apart from each other. For example, the semiconductor layer sequence includes a continuous broadened region, in particular only a continuous broadened region.

[0018] According to at least one embodiment of the method for manufacturing at least one semiconductor laser, a principal orientation of the broadened region runs transversely or perpendicularly to a principal orientation of the bridge waveguide. The principal orientation of the bridge waveguide can, for example, be the direction along which the bridge waveguide has its greatest extent. For example, the principal orientation of the bridge waveguide runs parallel or nearly parallel to a resonator of the semiconductor laser. The resonator of the semiconductor laser is, for example, arranged between two resonator faces. For example, one of the resonator faces has an output facet of the semiconductor laser. The principal orientation of the broadened region can run transversely or perpendicularly to the principal orientation of the bridge waveguide.For example, the widened area can cut through at least one of the waveguides.

[0019] According to at least one embodiment, the method for manufacturing at least one semiconductor laser comprises forming at least one main structure of the semiconductor laser from the broadened region. The at least one main structure can thus be formed from the material of the broadened region. The at least one main structure can, for example, be formed by structuring the broadened region. For example, when structuring the broadened region, a recess is created in the broadened region. For example, when creating the recess, a side face(s) of the main structure is / are formed and / or the main structure is defined. The side faces of the main structure can also be referred to as the side surface of the main structure in the following.The side surface of the main structure can then encompass all surfaces of the main structure that extend perpendicularly or at least approximately perpendicularly to the principal extension plane of the semiconductor layer sequence. The side surface of the main structure can, for example, directly adjoin the recess and at least partially define the lateral boundaries of the recess.

[0020] Alternatively, more than one recess can be formed. The recesses are then, for example, spaced apart from each other. In particular, each recess can be arranged between a first section and a second section of a waveguide.

[0021] The recess can be designed, for example, to extend through the semiconductor layer sequence in certain areas. For instance, the recess may also extend into the substrate. The recess can, for example, divide the waveguide into a first and a second section. In other words, the recess can be located between the first and second sections of the waveguide. The recess in the widened area can be created, for example, by dry chemical etching. The side surface of the main structure may therefore exhibit etch marks.

[0022] The recess can be flush with the widened region in a direction parallel to the main extension direction of the web waveguide. Alternatively, the recess can project beyond the widened region at least partially along this direction, for example, by at least 1 pm, or at least 5 pm. The recess can project beyond the widened region by, for example, a maximum of 50 pm, or at most 30 pm, or at most 10 pm. It is also possible for the recess to be located entirely within the widened region in a lateral direction. The width of any edge of the widened region surrounding the recess can then be between 0.1 pm and 5 pm inclusive, for example, between 0.2 pm and 3 pm inclusive. For example, a side of the main structure facing away from the recess may abut the web waveguide at least partially.It is possible that the side of the main structure facing away from the recess is directly adjacent to the waveguide. For example, the main structure extends the waveguide. The main structure is, for example, located in an optically active region of the semiconductor laser. In contrast to an optically passive region, the optically active region of the semiconductor laser can be a region from which electromagnetic radiation is coupled out during operation.

[0023] The main structure can thus be, for example, a structured region of the widened area that directly adjoins the bridge waveguide. The main structure can be designed as part of the widened area and / or as part of the bridge waveguide. The side surface of the main structure is curved or kinked in the lateral direction, at least in some places. The main structure can project beyond the recess along the principal direction of extension of the bridge waveguide. In other words, the main structure is, for example, designed as a projection from the widened area. The projection extends, for example, a length between 1 pm and 60 pm (inclusive), or between 5 pm and 30 pm (inclusive), into the recess. For example, the side surface of the main structure then runs, at least in some places, transversely or perpendicular to the principal direction of extension of the widened area.According to at least one embodiment of the method for manufacturing at least one semiconductor laser, the main structure is connected to the waveguide. For example, the main structure can be adjacent to the waveguide, in particular directly adjacent to it. Alternatively or additionally, the main structure can be formed integrally with the waveguide.

[0024] The bridge waveguide can transition into the main structure. This can mean that the main structure is arranged, at least partially, along the principal orientation of the bridge waveguide. For example, the main structure follows the bridge waveguide directly along its principal orientation. The edge of the broadened region can be located between the bridge waveguide and the main structure. The main structure can, for example, form the resonator. In particular, the main structure can define a resonator length for the semiconductor laser. For example, the resonator length is determined by a length of the bridge waveguide along its principal orientation and a length of the main structure along the principal orientation of the bridge waveguide.For example, the length of the bridge waveguide along its main direction of extension can range from 100 pm to 1500 pm. The main structure can extend the length of the bridge waveguide along its main direction of extension by, for example, a maximum of 60 pm to define the resonator length of the semiconductor laser.

[0025] According to at least one implementation form of the procedure for

[0026] To fabricate at least one semiconductor laser, the main structure comprises an output facet of the semiconductor laser. A region of the main structure's side surface, which, for example, is perpendicular or nearly perpendicular to the principal orientation of the waveguide, has, for instance, the resonator surface or the output facet. The output facet of the semiconductor laser can have a crystal plane that is perpendicular or approximately perpendicular to the principal orientation of the waveguide. The output facet is, for example, the side of the main structure facing away from the waveguide. The side surface of the main structure can be formed, at least partially, by the resonator surface and / or the output facet.The coupling facet, for example, is the surface of the semiconductor laser at which electromagnetic radiation is coupled out of the semiconductor laser during operation.

[0027] According to at least one embodiment of the method for manufacturing at least one semiconductor laser, the main structure is step-like. For example, the main structure comprises two steps, or at least two steps. The main structure can also comprise at least three steps or a plurality of steps.

[0028] The stages of the main structure are arranged, for example, along the main direction of extension of the bridge waveguide. A first stage can be located closest to the bridge waveguide. Thus, the first stage can be located, for example, between the bridge waveguide and another stage along the main direction of extension of the bridge waveguide. For example, the second stage is located between the output facet of the main structure and the first stage. Alternatively or additionally, the second stage can have the output facet.

[0029] The steps can be characterized, for example, by having different extensions along a direction perpendicular or approximately perpendicular to the main extension direction of the waveguide. Alternatively or additionally, the step can project beyond the next step in a lateral direction parallel to the main extension direction of the widened area, or vice versa. In other words, the stepped main structure can exhibit steps and / or a variety of angles and changes in direction when viewed from above.

[0030] According to at least one embodiment of the method for manufacturing at least one semiconductor laser, at least one minor structure is formed from the broadened region. For example, the minor structure is laterally spaced from the main structure.

[0031] The fact that at least one minor structure is formed from the broadened region can mean that the minor structure consists of the same material as the broadened region. The minor structure can thus be implemented as part of the broadened region. For example, the minor structure is not implemented as part of the bridge waveguide and is spaced apart from it. In particular, the minor structure is located laterally to the bridge waveguide. In other words, the bridge waveguide does not transition into the minor structure. For example, the minor structure does not have a side surface from which electromagnetic radiation generated during the operation of the semiconductor laser is coupled out. The minor structure can be formed, for example, using the same method as the main structure and / or in a joint process with the main structure.In other words, all features that can be used to form the main structure can be used to form the substructure, and vice versa.

[0032] For example, when creating the recess, the side surface of the minor structure is formed. The recess can be created by dry chemical etching. The side surface of the minor structure can at least partially define the lateral boundaries of the recess. The side surface of the minor structure can then encompass all surfaces of the minor structure that extend perpendicularly or at least approximately perpendicularly to the principal extension plane of the semiconductor layer sequence. For example, two sub-regions of the side surface of the minor structure can form an angle other than 180°. In other words, the side surface of the minor structure can, for example, in a top view of the semiconductor layer sequence, extend at least partially transversely or perpendicularly to the principal extension direction of the widened region and / or be curved and / or kinked in places. In a top view, the minor structure can exhibit convex and / or concave features.In particular, the side surface of the secondary structure can be convex or concave, at least in some areas. In other words, the secondary structure can, for example, be formed as a projection from the widened region. The secondary structure may, for example, project a length between 0.5 pm and 60 pm (inclusive), or between 5 pm and 30 pm (inclusive), into the recess. The secondary structure can be spaced apart from the main structure. For example, the secondary structure may be located in the optically passive region of the semiconductor laser. The optically passive region may be a region of the semiconductor laser in which no electromagnetic radiation is generated or coupled out during operation. It is possible that the secondary structure does not have a resonator surface and / or coupling facet of the semiconductor laser.In particular, no electromagnetic radiation generated in the active region of the semiconductor laser can be coupled out at the secondary structure. For example, the secondary structure does not directly border the main waveguide. Specifically, the secondary structure can be arranged such that it does not follow the main waveguide along its principal direction of extension. For example, the semiconductor layer sequence comprises two main waveguides with main structures arranged on them. At least one secondary structure, or at least two secondary structures, can be arranged between the two main structures. Thus, the broadened region between two main structures can have at least two projections.

[0033] In at least one embodiment of the method for fabricating at least one semiconductor laser, a semiconductor layer sequence comprising at least one bridge waveguide and a broadened region is provided, wherein a principal orientation of the broadened region is transverse or perpendicular to a principal orientation of the bridge waveguide. At least one principal structure of the semiconductor laser is formed from the broadened region, the principal structure being connected to the bridge waveguide and comprising an output facet of the semiconductor laser. The principal structure is step-shaped and / or at least one minor structure is formed from the broadened region, which is laterally spaced from the principal structure.

[0034] The method described here for manufacturing at least one semiconductor laser allows for the efficient production of a semiconductor laser. Among other things, the at least one semiconductor laser can be manufactured cost-effectively. In particular, the resonator surfaces and / or the output facet of the semiconductor laser can be produced by etching. By forming a step-shaped main structure or a minor structure laterally spaced from the main structure, under-etching of the output facet, especially during wet chemical etching to expose the crystal plane of the output facet or to smooth the side surfaces of the main structure and / or the minor structure, can be minimized, reduced, or prevented. This allows for the efficient production of a high-quality resonator surface or output facet. The wet chemical etching can therefore be specifically controlled by a recessed shape, or...The shape of the main structure and / or substructure can be influenced to achieve particularly smooth resonator surfaces through etching. Furthermore, a large number of resonator surfaces can be produced simultaneously with minimal loss.

[0035] According to at least one embodiment of the process for manufacturing a semiconductor laser, the output facet of the semiconductor laser is produced by means of wet chemical etching.

[0036] Wet chemical etching allows material to be removed not only vertically but also laterally. This material can consist of the layers of the semiconductor layer sequence. For example, wet chemical etching can etch the semiconductor layer sequence material along the lateral direction. This can smooth the surface of the main structure. The mean surface roughness of the main structure after wet chemical etching might be a maximum of 50 nm, 30 nm, or 10 nm. Specifically, the RMS roughness is...

[0037] (English: root mean square roughness) for example, a maximum of 10 nm, for example, a maximum of 2 nm, or for example, a maximum of 1 inm. The resonator surface and / or the output coupling facet of the semiconductor laser can be formed, for example, by wet chemical etching of the side surface of the main structure. The side surface of the main structure can exhibit a crystal plane in certain areas, particularly only in certain areas, which runs perpendicular or nearly perpendicular to the main orientation of the waveguide. The crystal plane running perpendicular to the main orientation of the waveguide is exposed on the side surfaces of the main structure, for example, by means of wet chemical etching. The output coupling facet can, for example, exhibit etch marks.

[0038] The output facet can therefore be etched into individual semiconductor lasers before the separation of a semiconductor laser array. In particular, the output facet is not created only during the separation process, for example by breaking.

[0039] According to at least one embodiment, the at least one minor structure is trapezoidal or semicircular in plan view of the semiconductor layer sequence. The minor structure can then have at least two crystal planes. For example, the side face of the minor structure facing the recess has at least one change of direction. At this change of direction, the side face of the minor structure can be curved and / or kinked. The minor structure can, for example, be semicircular in plan view. The minor structure then exhibits, for example, a multitude of changes of direction. Alternatively, the minor structure can be step-shaped and, for example, have a trapezoidal or semicircular outline in plan view. It is possible that all side faces of the minor structure exhibit etch marks.For example, in the finished semiconductor laser, all exposed side surfaces of the secondary structure may show etch marks.

[0040] Due to the large number of changes in direction, the occurrence of undercutting or incutting during the creation of the resonator surfaces, for example the output coupling facet, can be reduced or prevented by wet chemical etching.

[0041] Alternatively or additionally, the main structure can be trapezoidal or semicircular in plan view.

[0042] According to at least one embodiment of the method for fabricating a semiconductor laser, the semiconductor layer sequence comprises at least two bridge waveguides, wherein at least two main structures are formed in the broadened region, and at least two minor structures are formed in the broadened region, the at least two minor structures being arranged between the main structure and an adjacent further main structure. The at least two main structures are formed, for example, on the at least two bridge waveguides. In particular, a main structure can be formed on each bridge waveguide. Alternatively or additionally, at least one main structure can be formed on each region of the bridge waveguide that later forms a semiconductor laser. The fact that two main structures are adjacent can, in particular, mean that no further main structure is arranged between them.However, at least one subsidiary structure or a plurality of subsidiary structures can be arranged between two adjacent main structures.

[0043] By forming at least two subsidiary structures, the recess in the widened area can have a structure that allows a high-quality resonator surface, for example the output facet of the semiconductor laser, to be produced by means of wet chemical etching.

[0044] According to at least one embodiment of the process for manufacturing a semiconductor laser, the main structure and at least one minor structure are formed in a common etching process.

[0045] The main structure and minor structure of the semiconductor laser can be formed by a dry chemical etching process, for example, plasma etching. In this process, regions of the broadened area that do not form a main or minor structure of the semiconductor laser are removed by dry chemical etching. In other words, the broadened area can be structured by dry chemical etching while preserving the regions of the broadened area that form at least one main structure and at least one minor structure of the semiconductor laser. Specifically, the regions of the broadened area that form at least one main structure and at least one minor structure of the semiconductor laser are not removed when the recess is created.

[0046] For example, the main structure and the minor structure are formed before the wet chemical etching of the resonator plate. However, it is also possible for the main structure and the minor structure to be generated sequentially using dry chemical etching.

[0047] For example, the surface areas of the main structure and the secondary structure are smoothed in a common wet chemical etching process. During wet chemical etching, it is possible that etch marks may spontaneously form, depending on the structure or arrangement of the semiconductor layer sequence and / or due to the atomic concentration within the semiconductor layer sequence. These etch marks can, for example, occur in the active region.

[0048] By forming the main and minor structures before wet chemical etching, the occurrence of etching can be prevented or at least reduced. This is achieved, for example, by the presence of a variety of different crystal planes on the minor and / or main structure. Lateral propagation of etching is slowed down, for instance, on convex and / or concave structures. The minor structures can influence, for example, the etching behavior at the output facet during wet chemical etching. The facet quality, for example, of the output facet, can be improved by avoiding etching.

[0049] According to at least one embodiment, the main structure has, at least in some places, a crystal plane perpendicular to the main direction of extension of the waveguide, which forms the output coupling facet. The electromagnetic radiation generated by the active region can be efficiently coupled out of the semiconductor laser at a crystal plane perpendicular to the main direction of extension of the waveguide.

[0050] According to at least one embodiment, the main structure has at least two stages along the main direction of extension of the waveguide. The side surface of the main structure can be convex and / or concave, in particular curved or kinked, in the region of the two stages and / or in a transition from the first stage to the next stage.

[0051] This prevents the occurrence of etching during wet chemical etching.

[0052] According to at least one embodiment of the method for manufacturing a semiconductor laser, a first stage located closest to the waveguide has a lateral extent that is smaller than the extent of a further stage located between the first stage and the output facet. For example, the first stage has a lateral

[0053] Extension onto , which is smaller than the width of the

[0054] The bridge waveguide is . The main structure can then have an undercut when viewed from above on the resonator surface.

[0055] The formation of an undercut, for example, creates different crystal planes and / or a large number of changes in direction. These can have a positive influence on the quality of the resonator surface of the semiconductor laser during wet chemical etching, as the etching process is slowed down by the numerous changes in direction or by the convex and / or concave structures of the main structure.

[0056] According to at least one embodiment of the method for manufacturing a semiconductor laser, the broadened region is structured in the lateral direction before the formation of at least one major structure and / or at least one minor structure. The structuring includes, for example, at least one transition where a side surface of the broadened region is curved and / or kinked.

[0057] The widened region has, for example, at least one notch extending away from the output facet of the semiconductor laser. The widened region can have multiple notches. For example, one side of the widened region is at least approximately wave-shaped. The notches can be trapezoidal or semicircular in plan view. The notches extend, for example, at least 2 pm, or at least 5 pm, away from the output facet of the semiconductor laser. For example, the notches protrude at most 50 pm, or at most 30 pm, beyond the output facet.

[0058] According to at least one embodiment of the process for manufacturing a semiconductor laser, a recess in the widened region is formed such that the structure of the recess follows the structure of the widened region. For example, the main structure is convex. Alternatively, it is possible to form the main structure simply by means of a laterally flat region within the widened area. The secondary structure is, for example, convex or concave.

[0059] One idea behind this design is to increase the edge length of the face of the main structure and / or the subsidiary structure. Furthermore, different crystal axes can be formed.

[0060] According to at least one embodiment of the process for manufacturing a semiconductor laser, a large number of semiconductor lasers are produced in a common process. The large number of semiconductor lasers can be separated into multiple emitters and / or single emitters.

[0061] For example, the semiconductor laser array is singulated into semiconductor lasers. A semiconductor laser can then, for example, comprise only one waveguide or a section of a waveguide. Alternatively, the semiconductor laser array can be singulated into at least one multiple emitter. The finished semiconductor laser can then comprise more than one waveguide. A main structure with an output facet can be arranged on each waveguide. At least one minor structure or a plurality of minor structures can be arranged between the main structures. For example, the semiconductor laser array is separated, or singulated, along the cutout in a direction parallel to the main orientation of the widened area. It is also possible for the semiconductor laser array to be singulated parallel to the main orientation of a waveguide.The semiconductor laser array can be cut or separated, for example, approximately in the middle between two adjacent waveguides.

[0062] According to at least one embodiment of the process for manufacturing a semiconductor laser, at least one minor structure is generated laterally in the broadened region between the main structure and another main structure. This minor structure prevents lateral etching from the facet. A semiconductor laser with an etched output facet can thus be manufactured efficiently.

[0063] According to at least one embodiment of the process for manufacturing a semiconductor laser, at least one minor structure remains completely within the isolated semiconductor laser. If only one minor structure is arranged between the main structure and the subsequent main structure, then, alternatively, only approximately half of the minor structure may remain in the isolated semiconductor laser during the isolation process between the main structures.

[0064] Furthermore, a semiconductor laser is specified.

[0065] A semiconductor laser, for example, can be manufactured using a method described here. In other words, all features known for the method of manufacturing a semiconductor laser can be used for the semiconductor laser and vice versa.

[0066] According to at least one embodiment of the semiconductor laser, the semiconductor laser comprises a semiconductor layer sequence, wherein the semiconductor layer sequence includes a bridge waveguide and a broadened region. A principal orientation of the broadened region is transverse or perpendicular to a principal orientation of the bridge waveguide. The semiconductor layer sequence includes a principal structure connected to the bridge waveguide, wherein the principal structure includes an output facet of the semiconductor laser and is formed from the broadened region. The principal structure is configured as a step. Alternatively or additionally, the semiconductor layer sequence includes a minor structure formed from the broadened region and spaced laterally from the principal structure.

[0067] The semiconductor laser described here can have an output coupling facet produced by etching. This facet can be manufactured efficiently, cost-effectively, and with good quality. The efficiency and functionality of the semiconductor laser can be improved as a result.

[0068] According to at least one embodiment of the semiconductor laser, the main structure and / or the secondary structure has at least one side surface. This side surface extends, for example, at least partially transversely and / or perpendicularly to the main direction of extension of the broadened region. According to at least one embodiment of the semiconductor laser, the secondary structure, viewed from above the semiconductor layer sequence, is at least approximately trapezoidal, quarter-circle, or semicircular.

[0069] According to at least one embodiment of the semiconductor laser, the main structure has at least two stages along the main extension direction of the bridge waveguide.

[0070] According to at least one embodiment of the semiconductor laser, the semiconductor laser is designed as a multiple emitter with at least two main structures and at least one minor structure, wherein the minor structure is arranged at a distance from the main structures along the main extension direction of the broadened region.

[0071] The following section explains in more detail the method for manufacturing a semiconductor laser and the semiconductor laser described here in conjunction with exemplary applications and the associated figures.

[0072] Figures 1A and 1B show comparative examples of a semiconductor laser.

[0073] Figures 2 to 7 show steps in processes for the production of semiconductor lasers in schematic top view according to exemplary cases.

[0074] Figures 8 and 9 show step-like main or secondary structures in schematic top view according to exemplary embodiments. Figures 10 to 12 show intermediate steps in processes for the fabrication of semiconductor lasers according to exemplary embodiments in schematic top view.

[0075] Figures 13 to 15 show intermediate steps in processes for the production of semiconductor lasers according to further exemplary embodiments in schematic top view.

[0076] Figure 16 shows an intermediate step in the process for manufacturing a semiconductor laser according to a further embodiment in a schematic top view.

[0077] Identical, similar, or similarly effective elements are marked with the same reference symbols in the figures. The figures and the relative sizes of the elements depicted within them are not to be considered to scale. Rather, individual elements may be exaggerated for clarity and / or to improve representation.

[0078] Figure 1A shows a schematic representation of a resonator surface 46 of a semiconductor laser 1. An etching 7 has formed in an active region 21 of a semiconductor layer sequence 2. The etching 7 may have resulted from wet chemical etching. The resonator surface 46 may therefore be partially under-etched. The resonator surface 46 of the semiconductor laser 1 may, for example, be a facet of the semiconductor laser 1, in particular an output coupling facet 41 of the semiconductor laser 1.

[0079] Figure 1B shows a comparative example of a semiconductor laser 1 with a resonator surface 46 and an etch 7 in the active region 21 of the semiconductor layer sequence 2. The semiconductor layer sequence 2 has a bridge waveguide 3 and a widened region 32. A side surface 42 of a main structure 4 may be partially undercut by the etch 7. One idea of ​​the method described here for fabricating a semiconductor laser 1 is to minimize, reduce, or prevent the etch 7 shown in Figure 1A or 1B.

[0080] Figure 2 shows a schematic top view of a semiconductor layer sequence 2 in the process for manufacturing a semiconductor laser 1 according to an exemplary embodiment. Here and in the following, "top view" means, for example, that the viewing direction is perpendicular to a principal extension plane of the semiconductor layer sequence 2. In the process step shown here, a semiconductor layer sequence 2 is provided.

[0081] The semiconductor layer sequence 2 has at least one bridge waveguide 3. The semiconductor layer sequence 2 can have at least one further bridge waveguide 31. For example, the semiconductor layer sequence 2 has a plurality of bridge waveguides 3 and 31. The bridge waveguide 3 and the further bridge waveguide 31 run parallel or approximately parallel to each other.

[0082] The semiconductor layer sequence 2 has a widened region 32. A principal direction of extension of the widened region 32 extends transversely or perpendicularly to a principal direction of extension of the bridge waveguide 3. For example, the widened region 32 also extends transversely or perpendicularly to a principal direction of extension of the further bridge waveguide 31. The widened region 32 can be continuous, in particular formed as a single piece. For example, the widened regions 32 of the bridge waveguides 3 and 31 form a continuous widened region 32.

[0083] Figure 3 shows a schematic representation of a further process step in the process for manufacturing a semiconductor laser 1. Figure 3 shows a semiconductor laser array 10. The process step shown in Figure 3 follows, for example, the process step shown in Figure 2. In this step, at least one main structure 4 of the semiconductor laser 1 is formed from the widened region 32. The main structure 4 is connected to the waveguide 3. The main structure 4 comprises a resonator surface 46 of the semiconductor laser 1. The resonator surface 46 is, for example, an output facet 41 of the semiconductor laser 1.

[0084] At least one minor structure 5 can be formed from the widened region 32. This minor structure 5 can be formed during the formation of the main structure 4. The minor structure 5 is then laterally spaced from the main structure 4. For example, the minor structure 5 is laterally spaced from all main structures 4 and 45 generated from the widened region 32. The minor structure 5 is located between two adjacent main structures 4 and 45.

[0085] Figure 4 shows a step in a process for manufacturing a semiconductor laser 1 according to an exemplary embodiment in a schematic top view. The process step shown in Figure 4 is the completed semiconductor laser array 10, which can be separated in a subsequent process step into semiconductor lasers 1, single emitters 12 and / or multiple emitters 11 (see Figure 6).

[0086] In the embodiment shown here, the at least one main structure 4 and the at least one secondary structure 5 of the semiconductor laser 1 are trapezoidal. Alternatively or additionally, the main structures 4, 45 can be convex and / or concave in plan view, for example, stepped and / or circular. For example, at least one main structure 4, 45 is trapezoidal, at least one main structure 4, 45 is circular, and / or at least one main structure 4, 45 is stepped. All main structures 4, 45 of the semiconductor laser array 10 can have the same or approximately the same shape, or at least partially different shapes. The main structure

[0087] 4 has a side surface of 42.

[0088] The substructure 5 is arranged between two adjacent main structures 4 and 45. The substructure has a side surface 51. Another substructure 52 is arranged between the two adjacent main structures 4 and 45. This further substructure 52 is arranged between the substructure 5 and the further main structure 45.

[0089] For example, a lateral size d2 of the substructure

[0090] 5 less than or equal to a lateral size of the main structure 4, 45. For example, the lateral size of both the main structure 4, 45 and the minor structure 5 can be greater than 100 pm. Furthermore, the lateral size of both the main structure 4, 45 and the minor structure 5 can be less than 100 pm. For example, the main structures 4, 45 and / or the minor structures 5, 52 in the widened region were created or defined by forming a recess 6 by dry chemical etching. The recess 6 can extend vertically through the semiconductor layer sequence 2. For example, the recess 6 extends vertically completely through the semiconductor layer sequence 2, for example into a substrate (not shown).

[0091] The recess 6, for example, is formed as a continuous trench in the lateral direction. In other words, the recess 6 in the widened area 32 is continuous and extends completely, or at least approximately completely, across the extent of the widened area 32 in the lateral direction. For example, an extent of the recess 6 along the principal extension direction of the widened area 32 corresponds at least approximately to the extent of the widened area 32 along the principal extension direction of the widened area 32. "At least approximately" here can mean that the extents of the recess 6 and the widened area 32 along the principal extension direction of the widened area 32 are equal. Alternatively, the recess 6 may have a smaller extent along the principal extension direction of the widened area 32.

[0092] The recess 6 extends completely across the width of the bridge waveguide 3. The width of the bridge waveguide 3 is its extent perpendicular to its main direction of extension. The recess 6 is located between a first sub-section 35 of the bridge waveguide 3 and a further sub-section 36 of the bridge waveguide 3. After the semiconductor laser array 10 has been separated, the sub-sections 35 and 36 of the bridge waveguide 3 can be assigned to different semiconductor lasers 1.

[0093] In the widened area 32, a main structure 4 is arranged on the first sub-area 35 of the bridge waveguide 3 and on the further sub-area 36 of the bridge waveguide 3.

[0094] The main structure 4 and the minor structure 5 are formed, for example, in a common etching process. The output facet of the semiconductor laser 1 is produced, for example, by wet chemical etching.

[0095] Figure 5 shows a semiconductor laser array 10 according to a further exemplary embodiment.

[0096] The semiconductor laser array 10 of Figure 5 differs from the semiconductor laser array 10 shown in Figure 4 in that only one minor structure 5 is arranged between two adjacent main structures 4, 45.

[0097] Figure 6 shows a semiconductor laser array 10 according to a further exemplary embodiment.

[0098] The semiconductor laser array 10 of Figure 6 differs from the semiconductor laser array 10 shown in Figure 4 in that a secondary structure 5 and two further secondary structures 52 are arranged between the main structure 4 and the further main structure 45. The distance between the main structure 4 and the further main structure 45 can be at least approximately the same in the embodiments shown in Figures 4 to 6. Thus, the extent of the recess 6 between the main structure 4 and the secondary structure 5, or the extent of the secondary structure 5 along the main direction of extension of the widened region 32, can differ. Furthermore, here and in the further embodiments, the main structures 4, 45 and the secondary structures 5, 52 can have different dimensions, shapes, and distances from one another.

[0099] The multiple semiconductor lasers 1 in the semiconductor laser array 10 can be fabricated using a common process. Subsequently, the semiconductor laser array 10 can be singulated into multiple emitters 11 and / or single emitters 12. The semiconductor laser array is singulated, for example, along the singulation line LI and the singulation line L2. At least one substructure 5 can remain completely within the singulated semiconductor laser 1.

[0100] Figure 7 shows a semiconductor laser array 10 according to a further embodiment. The semiconductor laser array 10 comprises the bridge waveguide 3 with a first sub-section 35 and a further sub-section 36, and the further bridge waveguide 31. The further bridge waveguide also has a first and a second section. The first section 35 and the further section 36 are spaced apart from each other by a recess 6. A main structure 4 is arranged on the first sub-section 35 of the bridge waveguide 3. The main structure 4 is stepped. The main structure 4 has two steps 43, 44. In particular, the main structure 4 can have at least two steps 43, 44. A first step 43 is the step of the main structure 4 that is arranged closest to the bridge waveguide. Another stage 44 is arranged between the output facet 41 of the main structure 4 and the first stage 43.Alternatively or additionally, the further stage 44 can have the output facet 41.

[0101] Figure 8 shows a schematic top view of a stepped main structure 4 according to an exemplary embodiment. The main structure 4 has a first step 43 and a further step 44. Thus, the exemplary embodiment of the main structure 4 shown here has two steps.

[0102] Figure 9 shows a schematic top view of a step-shaped main structure 4 according to a further embodiment. In comparison to the embodiment shown in Figure 8, the main structure 4 shown here comprises a first stage 43 and two further stages 44. The further stage 44 has the output facet 41 of the semiconductor laser 1 on the side facing away from the first stage 43.

[0103] Alternatively, Figures 8 and 9 can also show examples of a step-shaped subsidiary structure 5.

[0104] Figures 10 to 12 show a schematic top view of a semiconductor laser array 10 according to an exemplary embodiment. In the exemplary embodiments shown in Figures 10 to 12, for example, the recess 6 is minimized. This minimizes the contact area of ​​the semiconductor layer sequence 2 that is in contact with an etching medium during wet chemical etching. This can reduce or prevent the formation of etching. In the exemplary embodiments shown in Figures 10 to 12, secondary structures 5 can also be generated.

[0105] Figure 10 shows an embodiment of a semiconductor laser array 10 with a continuous widened region 32. Alternatively, the widened region 32 can be formed from widened regions arranged at a distance from each other, as shown, for example, in Figure 11.

[0106] In the exemplary embodiment of Figure 12, the right recess 6 projects beyond the widened area 32.

[0107] Figure 13 shows a schematic top view of the semiconductor layer sequence 2 in a method for manufacturing at least one semiconductor laser 1 according to a further embodiment. The widened region 32 is structured laterally during the provision of the semiconductor layer sequence 2, i.e., before the formation of the at least one main structure 4 and / or the at least one minor structure 5, and the structuring has at least one transition 33 at which a side surface 34 of the widened region 32 is curved and / or folded. For example, the widened region has notches 37.

[0108] Figures 14 and 15 show a schematic top view of a semiconductor laser array 10 according to a further embodiment. The semiconductor laser array 10 of Figures 14 and 15 was formed by creating at least one main structure 4 and at least one minor structure 5 from the widened region of the semiconductor layer sequence 2 shown in Figure 13. The recess 6 is formed in the widened region 32 such that the structure of the recess 6 follows the structure of the widened region 32. In the embodiment shown in Figure 14, the main structure 4 is formed as a projection in the widened region 32. The main structure 4 is stepped. Alternatively, as shown in Figure 15, the main structure 4 is not stepped. In particular, the side surface of the main structure 4 is defined by the notch 37 of the widened region 32.

[0109] Figure 16 shows a semiconductor laser array 10 according to a further embodiment. The semiconductor laser array 10 comprises a plurality of semiconductor lasers 1. The semiconductor laser 1 includes at least the waveguide 3, wherein a main structure 4 from the widened region 32 is arranged on the waveguide 3. The main structure 4 is formed in a step-like manner. The main structure 4 has a first stage 43 located closest to the waveguide and a further stage 44. The further stage 44 is located between the first stage 43 and the output facet 41 of the semiconductor laser 1. The first stage 43 has a lateral extent that is smaller than the extent of the further stage 44. The semiconductor laser array 10 of Figure 16 has two subsidiary structures 5, 52 between each pair of adjacent main structures 4, 45.Alternatively, the semiconductor laser array 10 may have no, only one, or a plurality of secondary structures 5, 52 between adjacent main structures 4, 45. The features and embodiments described in connection with the figures can be combined with one another according to further embodiments, even if not all combinations are explicitly described. Furthermore, the embodiments described in connection with the figures may alternatively or additionally have further features as described in the general part. The invention is not limited to the embodiments described by reference to them. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes every combination of features in the claims, even if this feature or combination itself is not explicitly specified in the claims or embodiments.

[0110] Reference character list

[0111] 1 semiconductor laser

[0112] 10 semiconductor laser array

[0113] 11 multiple emitters

[0114] 12 individual emitters

[0115] 2 Semiconductor layer sequence

[0116] 21 active area

[0117] 3 waveguides

[0118] 31. Another bridge waveguide

[0119] 32 Widened area

[0120] 33 Transition

[0121] 34 Side surface of the widened area

[0122] 35 first section of the bridge waveguide

[0123] 36 further subsection of the bridge waveguide

[0124] 37 Notching of the widened area

[0125] 4 Main structure

[0126] 41 Exit facet

[0127] 42 Side surface of the main structure

[0128] 43 First stage

[0129] 44 Further level

[0130] 45 more main structures

[0131] 46 Resonator surface

[0132] 5 Substructure

[0133] 51 Side surface of the secondary structure

[0134] 52 additional substructures

[0135] 6 Exclusion

[0136] 7 Deployment

[0137] LI singulation line

[0138] L2 further singulation line

Claims

Patent claims 1. Method for producing at least one semiconductor laser (1) , comprising the following steps: - Providing a semiconductor layer sequence (2) with at least one bridge waveguide (3) and a widened region (32), wherein a principal extension direction of the widened region (32) is transverse or perpendicular to a principal extension direction of the bridge waveguide (3), and - Forming at least one main structure (4) of the semiconductor laser (1) from the broadened region (32) , wherein the main structure (4) is connected to the bridge waveguide and comprises an output coupling facet (41) of the semiconductor laser (1), and wherein - the main structure (4) is designed in a stepped manner and has at least two steps (43, 44) along the main extension direction of the bridge waveguide (3) and / or - at least one subsidiary structure (5) is formed from the widened area (32), which is laterally spaced from the main structure (4) and has a lateral size along the main extension direction of the widened area (32) that is less than or equal to the lateral size of the main structure (4).

2. Method for producing a semiconductor laser (1) according to the preceding claim, wherein the output coupling facet (41) of the semiconductor laser (1) is produced by wet chemical etching.

3. Method for manufacturing a semiconductor laser (1) according to one of the preceding claims, wherein the at least one Secondary structure (5) in top view of the The semiconductor layer sequence (2) is formed in a trapezoidal or semicircular shape.

4. Method for manufacturing a semiconductor laser (1) according to any one of the preceding claims, wherein - the semiconductor layer sequence (2) comprises at least two bridge waveguides (3, 31), - at least two main structures (4, 45) are formed in the broadened area (23), and - at least two subsidiary structures (5, 52) are formed in the widened area (23), wherein the at least two subsidiary structures are arranged between the main structure (4) and an adjacent further main structure (45).

5. Method for producing a semiconductor laser (1) according to one of claims 1 to 4, wherein the main structure (4) and the at least one subsidiary structure (5) are formed in a common etching process.

6. Method for manufacturing a semiconductor laser (1) according to one of the preceding claims, wherein the main structure (4) has at least partially a crystal plane perpendicular to the main extension direction of the bridge waveguide (3), which forms the output coupling facet (41).

7. Method for manufacturing a semiconductor laser (1) according to one of the preceding claims, wherein a first stage (43) arranged closest to the waveguide (3) has a lateral extent which is smaller than an extent of a further stage (44) located between the first stage (43) and the output coupling facet (41).

8. Method for producing a semiconductor laser (1) according to one of the preceding claims, wherein the widened region (32) is structured in a lateral direction prior to the formation of the at least one main structure (4) and / or the at least one minor structure (5), and the structuring has at least one transition (33) at which a side surface (34) of the widened region (32) is curved and / or kinked.

9. Method for manufacturing a semiconductor laser (1) according to claim 8, wherein a recess (6) in the widened area (32) is formed such that the structure of the recess (6) follows the structuring of the widened area (32).

10. Method for manufacturing a semiconductor laser (1) according to one of the preceding claims, wherein - a large number of semiconductor lasers (1) are manufactured in a common process, and - the multitude of semiconductor lasers (1) in multiple emitters (11) and / or individual emitter (12) is isolated.

11. Method for producing a semiconductor laser (1) according to the preceding claim, wherein the at least one subsidiary structure (5) is produced laterally in the widened region (32) between the main structure (4) and a further main structure (45).

12. Method for manufacturing a semiconductor laser (1) according to one of claims 9 to 10, wherein the at least one subsidiary structure (5) remains completely in the isolated semiconductor laser (1).

13. Semiconductor laser (1) with a semiconductor layer sequence ( 2 ) , wherein - the semiconductor layer sequence (2) has a bridge waveguide (3) and a widened region (32), - a principal extension direction of the widened area (32) runs transversely or perpendicularly to a principal extension direction of the bridge waveguide (3), - the semiconductor layer sequence (2) has a main structure (4), and - the main structure (4) is connected to the bridge waveguide (3), comprises an output coupling facet (41) of the semiconductor laser (1) and is formed from the widened region (32), and wherein - the main structure (4) is designed in a stepped manner and has at least two steps (43, 44) along the main extension direction of the bridge waveguide (3) and / or - the semiconductor layer sequence has at least one minor structure (5) formed from the broadened region (32) and separated from the main structure (4) is laterally spaced and has a lateral size along the main extension direction of the widened area (32) that is less than or equal to the lateral size of the main structure (4).

14. Semiconductor laser (1) according to claim 13, wherein the main structure (4) and / or the secondary structure (5) have at least one side surface (42, 51), and the at least one side surface (42, 51) extends at least partially transversely and / or perpendicularly to the main extension direction of the widened region (32).

15. Semiconductor laser (1) according to one of claims 13 to 14, wherein the secondary structure (5) is at least approximately trapezoidal, quarter-circle or semicircular in plan view of the semiconductor layer sequence (2).

16. Semiconductor laser (1) according to one of claims 13 to 15, which is designed as a multiple emitter (11) with at least two main structures (4, 45) and at least one secondary structure (5), wherein the secondary structure (5) is arranged spaced apart from the main structures (4, 45) along the main extension direction of the widened region (32).

Images