Method for producing a plurality of laser diodes and laser diode

Abstract

Method for producing a plurality of laser diodes (1) with the following method steps: - Providing a plurality of laser bars (2) in the composite (20), wherein the laser bars (2) each comprise a plurality of laser diode elements (3) arranged next to one another, and the laser diode elements (3) have a common substrate (4) and each have a semiconductor layer sequence (5) arranged on the substrate (4), and wherein a division of the composite (20) at a respective longitudinal separation plane (y-y') running between two adjacent laser bars (2) leads to a formation of laser facets (1C) of the laser diodes (1) to be produced, - Structuring the composite (20) on at least one longitudinal separation plane (y-y'), wherein a structured region (8) is produced in the substrate (4), and the structured region (8) has a depression (9) running continuously along the longitudinal separation plane (y-y'), wherein the continuously running depression (9) has a composite shape which is composed of a larger partial region (90) and a plurality of smaller partial regions (91) adjoining the larger partial region (90), wherein the smaller partial region (91) follows the larger partial region (90) in a vertical direction (V), and wherein the smaller partial regions (91) each have a width (B2) which is greater than a width (B) of the laser diode elements (3), and wherein the structured region (8) extends into the substrate (4) starting from a surface of the substrate (4) facing away from the semiconductor layer sequence (5).

Description

[0001] A method for producing a plurality of laser diodes is provided. In particular, the laser diodes are separated from a plurality of laser bars arranged in a composite. Furthermore, a laser diode that can be produced using the method is provided.

[0002] One possible method for separating laser bars arranged in a composite is to break the laser bars. In this process, the composite is preferably broken at crystal planes of a material used for the laser bars, thereby forming laser facets for the laser diodes to be produced. Ideally, the fracture surfaces are atomically smooth to ensure a low roughness suitable for laser operation and sufficient optical reflectivity.

[0003] However, forming the laser facets presents a technical challenge, as various factors such as the type of fracture process, the initiation of fracture at introduced notches, and global and local stress conditions of the laser bar composite influence the quality of the laser facets. For example, unfavorable stress conditions can lead to crystal steps on the laser facets, which, on the one hand, impair reflectivity and lead to lower light output, and, on the other hand, pose a quality risk because they can cause spontaneous failures. However, a fundamental structural change to the laser bar composite cannot be easily implemented, as this can impair fracture and, on the other hand, the functionality of the finished laser diodes.

[0004] The document DE 40 25 144 A1 discloses a method for the selective coating of light-emitting semiconductor components.

[0005] The document JP 2012-243 866 A discloses a light-emitting semiconductor device and a method for its production.

[0006] The document US 2009 / 0 185 594 A1 discloses a semiconductor laser component and a method for its production.

[0007] The document DE 29 41 476 A1 discloses a method for dividing semiconductor microdisks into individual pieces.

[0008] One object of the present application is to provide an improved method for producing a plurality of laser diodes. This object is achieved, inter alia, by a manufacturing method having the features of the independent method claim.

[0009] Advantageous developments of the manufacturing process are the subject of the dependent claims.

[0010] According to at least one embodiment, the method for producing a plurality of laser diodes comprises the following method steps: - Providing a plurality of laser bars in a composite, wherein the laser bars each comprise a plurality of laser diode elements arranged next to one another, and the laser diode elements have a common substrate and a semiconductor layer sequence arranged on the substrate, and wherein a division of the composite at a longitudinal separation plane running between two adjacent laser bars leads to the formation of laser facets of the laser diodes to be produced, - Structuring the composite at at least one longitudinal separation plane, whereby a structured area is created in the substrate.

[0011] The above-mentioned procedural steps are carried out in the specified order.

[0012] Advantageously, by structuring the substrate, which is less important for the optical reflectivity than the semiconductor layer sequence, a fundamental intervention in the laser design can be avoided.

[0013] Providing the plurality of laser bars in the composite preferably comprises providing a substrate and a semiconductor layer sequence comprising a plurality of semiconductor layers. The semiconductor layer sequence is preferably structured so that a semiconductor layer sequence can be assigned to each laser diode element.

[0014] The semiconductor layer sequence comprises, in particular, at least one active zone suitable for generating electromagnetic radiation. The layers of the semiconductor layer sequence preferably contain at least one III / V semiconductor material, for example a material from the material systems InxGayAl1-x-yP, InxGayAl1-x-yN, or InxGayAl1-x-yAs, each with 0 ≤ x, y ≤ 1, and x + y ≤ 1. III / V semiconductor materials are particularly suitable for generating radiation in the ultraviolet (InxGayAl1-x-yN), through the visible (InxGayAl1-x-yN, in particular for blue to green radiation, or InxGayAl1-x-yP, in particular for yellow to red radiation) and into the infrared (InxGayAl1-x-yAs) spectral range. Suitable materials for the substrate include, for example, sapphire, SiC, InP, GaAs, and / or GaN. The substrate is, for example, the growth substrate on which the semiconductor layer sequence is grown layer by layer.

[0015] The active zone of the semiconductor layer sequence preferably has a pn junction, a double heterostructure, a single quantum well (SQW) structure, or a multiple quantum well (MQW) structure for radiation generation. For the purposes of this application, the term "quantum well structure" encompasses, in particular, any structure in which charge carriers can experience quantization of multiple energy states through confinement. In particular, the term "quantum well structure" does not specify the dimensionality of the quantization. It thus encompasses, among other things, quantum wells, quantum wires, and quantum dots, and any combination of these structures.

[0016] Furthermore, the semiconductor layer sequence comprises, in particular, an n-type semiconductor region and a p-type semiconductor region, with the active zone arranged therebetween. The n-type semiconductor region, the active zone, and the p-type semiconductor region can each comprise one or more layers. It is possible for the n-type semiconductor region, the active zone, and the p-type semiconductor region to contain one or more undoped layers.

[0017] The longitudinal separation planes are preferably aligned along the individual laser bars, in particular parallel to the alignment of the individual laser bars. The separation of the composite into a plurality of laser diodes preferably takes place at the longitudinal separation planes and at transverse separation planes running transversely to the longitudinal separation planes. In a preferred embodiment of the method, the separation of the composite takes place by breaking at the longitudinal and transverse separation planes. Separation points are advantageously created in the composite on a side opposite the substrate at the longitudinal separation plane, which are provided for targeted division of the composite. Furthermore, the composite can be formed with further separation points on a side opposite the substrate along the transverse separation plane. The separation points are in particular depressions in the composite that enable targeted division.

[0018] In this context, "laser facet" refers to an interface, in particular a side surface, of the laser diode elements, which forms part of an optical resonator in the finished laser diode. The laser facet is characterized by its smooth design. "Smooth" here means, in particular, that the surface roughness of the laser facet is significantly smaller than the wavelength of the light generated by the laser diode during operation, preferably smaller than half the wavelength, particularly preferably smaller than a quarter of the wavelength.

[0019] In a preferred embodiment of the method, the laser diode elements are each formed with a contact region, in particular a p-conducting contact region, on a first main surface. In the finished laser diode, the contact region serves as an electrical connection region. Furthermore, the laser diode elements can each be formed with a further contact region, in particular an n-conducting contact region, on a second main surface opposite the first main surface. In the finished laser diode, the further contact region serves as a further electrical connection region. Suitable materials for the contact regions are electrically conductive materials, preferably pure metals or metal compounds.

[0020] The composite can be structured by mechanical sawing or by an etching process. Possible etching processes include laser etching, wet-chemical etching, or dry etching. Structuring involves material removal from the substrate, i.e., a local reduction in the substrate thickness.

[0021] By means of the structuring, a structured region arranged at the longitudinal separation plane can be created in the substrate. The structured region preferably has a main direction of extension running parallel to the alignment of the laser bars. Particularly preferably, the structured region is formed axially symmetrically with respect to the longitudinal separation plane.

[0022] The stress distribution can be advantageously influenced by the specifically introduced structured region. The inventors have discovered that the structured region can be used to increase the maximum tensile stress prevailing on a first main surface of the laser bar composite. Furthermore, the structured region makes it possible to increase the maximum compressive stress prevailing on a second main surface opposite the first main surface. For example, with a local reduction in the thickness of the laser bar composite by 20%, the maximum tensile stress can be increased by up to two times. The achievable values vary depending on the shape of the structured region. Increasing the maximum tensile stress on the first main surface has a particularly favorable effect on the dicing process and leads to improved quality of the laser facets.

[0023] According to at least one embodiment, the structured region has a depression that runs continuously, i.e., coherently, along the longitudinal separation plane or along its main extension direction. In particular, the structured region has only a single depression. The single depression extends largely through the laser bar composite along the longitudinal separation plane. Alternatively, the structured region can have a plurality of depressions that are separated from one another along the longitudinal separation plane, with each two adjacent depressions being separated from one another by a substrate region. Preferably, the at least one depression is at least partially delimited laterally, i.e., in directions parallel to a main extension plane of the substrate, by the substrate. The depth of the at least one depression is preferably between 10 and 90% of the thickness of the composite, including the boundaries.In particular, the depth is between 1 µm and 100 µm, including the boundaries. In a preferred embodiment, the continuously extending depression has a prismatic, for example, cuboid, or (semi-)cylindrical shape. In a longitudinal section arranged parallel to the longitudinal separation plane, the depression then has, in particular, a polygonal shape. For example, the continuously extending depression can have a rectangular shape in a longitudinal section arranged parallel to the longitudinal separation plane. In particular, the depth of the depression does not change along the longitudinal separation plane.

[0024] Furthermore, the continuously extending recess along the longitudinal separation plane can have alternating regions of different depths. In particular, the deeper regions are arranged in the region of the laser diode elements, so that the stress conditions can be influenced specifically in the region of the laser diode elements. Preferably, the deeper regions each have a width that is greater than the width of the laser diode elements.

[0025] The continuously running depression can have a composite shape. For example, the composite shape can be composed of a larger sub-region and a plurality of smaller sub-regions adjacent to the larger sub-region. Preferably, the smaller sub-region follows the larger sub-region in a vertical direction. The vertical direction refers in particular to the direction in which the semiconductor layer sequence follows the substrate. For example, the larger sub-region can have the shape of a prism, in particular a cuboid. Furthermore, the smaller sub-regions can have the shape of a prism, in particular a cuboid, a pyramid or hemisphere. In particular, the deeper regions are each composed of a section of the larger sub-region and a smaller sub-region, while the other regions consist of a section of the larger sub-region.Preferably, the smaller subregions each have a width that is greater than the width of the laser diode elements. The width of the laser diode elements or laser diodes is preferably between 50 µm and 1000 µm, particularly preferably between 100 µm and 400 µm, including the boundaries. In particular, the deeper regions or smaller subregions are twice as wide as the laser diode elements or laser diodes.

[0026] According to at least one embodiment, the structured region has a plurality of recesses. These recesses can each have a polygonal or semicircular shape in a longitudinal section arranged parallel to the longitudinal separation plane. The recesses can have the shape of a prism, in particular a cuboid, a pyramid, a cylinder, or a hemisphere. Preferably, the recesses each have a width that is greater than the width of the laser diode elements.

[0027] In a preferred embodiment, the structured region has a polygonal or semicircular shape in a cross-section arranged perpendicular to the longitudinal separation plane. In particular, the at least one recess can have a polygonal shape, for example a rectangular shape, or a semicircular shape, resembling, for example, a semioval or a semicircle. A maximum lateral extent of the structured region, determined perpendicular to the longitudinal separation plane, is preferably between 0.5 and 50 µm, including the boundaries.

[0028] According to at least one embodiment, the structured region extends from a surface of the substrate facing away from the semiconductor layer sequence into the substrate. Preferably, the surface of the substrate facing away from the semiconductor layer sequence is arranged on a rear side of the laser bar assembly defined by the second main surface of the laser bar assembly. The structured region at least partially penetrates the substrate. In other words, the structured region can end in the substrate or extend through it, thereby completely penetrating the substrate.

[0029] According to at least one embodiment of the method, the semiconductor layer sequence of the laser diode elements is each formed with a ridge structure. The ridge structure is formed, in particular, by a raised region of the semiconductor layer sequence with a main direction of extension that runs, in particular, parallel to the transverse separation plane. The finished laser diodes are preferably so-called ridge waveguide laser diodes, with the ridge structure acting as a lateral waveguide for the emitted light. Alternatively, the laser diodes can be formed as broad-area lasers. In this case, the formation of a ridge structure is omitted.

[0030] According to at least one embodiment of a laser diode, the latter comprises a semiconductor body with a substrate and a semiconductor layer sequence arranged on the substrate, which comprises an active zone suitable for generating electromagnetic radiation. The semiconductor body has a first main surface and a second main surface opposite the first main surface, and at least one first and second laser facet, each arranged transversely to the first and second main surfaces.

[0031] "Transverse" means that a normal vector of the laser facets does not run parallel to a normal vector of the first and / or second main surface. The laser facets preferably each delimit the semiconductor body in a lateral direction. The lateral directions are arranged in a plane that is arranged in particular parallel to a main extension plane of the substrate. The first main surface is preferably a surface of the semiconductor layer sequence that delimits the semiconductor body on a side of the active zone facing away from the substrate. In addition to the laser facets, the semiconductor body can have further side surfaces, each of which is arranged transversely to the first and second main surfaces.

[0032] The laser diode advantageously has at least one structured facet region located at the transition between the second main surface and at least one of the two laser facets. The structured facet region has an indentation. In the region of the indentation, the semiconductor body has a reduced thickness. The indentation is open, in particular, on one side, i.e., the indentation is laterally delimited at most partially by the semiconductor body. Due to the structured facet region, the laser facets are at least approximately smooth and thus exhibit high optical reflectivity.

[0033] The structured facet region may extend parallel to an edge of the semiconductor body located at the transition between the second main surface and the laser facet.

[0034] In an advantageous embodiment, the indentation extends from the substrate through the semiconductor layer sequence at most to the active zone. In particular, the laser diode remains largely unstructured in the region of the active zone. The indentation can have a uniform depth. Depending on the depression, the indentation can be between 1 µm and 100 µm deep, including the boundaries. The indentation has a first lateral dimension that corresponds at most to the width of the laser diode, i.e. the indentation extends at most over the entire width of the laser diode. Preferably, the indentation has a first lateral dimension between 50 µm and 1000 µm, particularly preferably between 100 µm and 400 µm, including the boundaries.Furthermore, the indentation has a second lateral dimension which preferably corresponds to half the lateral dimension of the structured region or of the at least one depression, i.e. the indentation preferably has a second lateral dimension of 0.25 to 25 µm, the boundaries being included.

[0035] Furthermore, the indentation can have a polygonal, in particular rectangular, shape in a cross-section arranged parallel to the laser facets. Furthermore, the indentation can have a polygonal shape or the shape of a quarter-oval or quarter-circle in a longitudinal section arranged perpendicular to the laser facets. The laser diode is preferably an edge emitter. During operation, laser radiation is emitted at one of the laser facets parallel to a normal vector of the laser facet.

[0036] Further advantages, preferred embodiments and further developments of the method and the laser diode can be found in the explanations of the Fig. 1 to 16B.

[0037] They show: Fig. 1 a schematic perspective view of a laser bar assembly according to a first embodiment, Fig. 2A is a schematic longitudinal sectional view of the laser bar assembly according to the first embodiment and Fig. 2B shows a section of a schematic cross-sectional view of the laser bar assembly according to the first embodiment, Fig. 3A is a schematic longitudinal sectional view of a laser bar assembly according to a comparative example and Fig. 3B shows a section of a schematic cross-sectional view of the laser bar assembly according to the comparative example, Fig. 4 to 10 are schematic longitudinal sectional views and Fig. 11 to 15 each show schematic cross-sectional views of laser bar composites according to various embodiments, Fig. 16A is a schematic cross-sectional view and Fig. 16B is a schematic longitudinal sectional view of a laser diode according to an embodiment.

[0038] In connection with the Fig. 1 to 15, various embodiments of a method and a laser bar assembly are described.

[0039] Fig. Figure 1 shows a schematic perspective view of a composite 20 comprising a plurality of laser bars 2. The composite 20 may well comprise more than the laser bars 2 shown. The laser bars 2 each comprise a plurality of laser diode elements 3 arranged next to one another, the number of which may differ from the number shown. Fig. 2A and 4 to 10 show schematic longitudinal sectional views along a longitudinal separation plane yy' and the Fig. 11 to 15 schematic cross-sectional views of various embodiments of laser bar composites along a transverse separation plane x-x'.

[0040] In one embodiment of a method for producing a plurality of laser diodes 1 (cf. Fig. 16A and Fig. 16B), the composite 20 of laser bars 2 is first provided. The laser bars 2 each comprise a plurality of laser diode elements 3 arranged side by side, each having a common substrate 4 and a semiconductor layer sequence 5 arranged on the substrate 4.

[0041] After the composite 20 has been provided, the composite 20 is structured, i.e., its structure is changed, at a longitudinal separation plane y-y', creating a structured region 8 in the substrate 4. The structuring process involves, in particular, removing material from the substrate 4, i.e., locally reducing the thickness of the substrate 4. The structuring can be performed by mechanical sawing or by an etching process. Possible etching processes include, for example, laser etching, wet-chemical etching, or dry etching.

[0042] Preferably, the structured region 8 has a main extension direction H running parallel to the alignment of the laser bars 2. The structured region 8 can be formed axially symmetrically with respect to the longitudinal separation plane yy' or the main extension direction H.

[0043] The laser diode elements 3 can each be formed with a contact region 10, in particular a p-type contact region, on a first main surface. In the finished laser diode 1, the contact region 10 serves as an electrical connection region. Suitable materials for the contact regions 10 are electrically conductive materials, preferably pure metals or metal compounds.

[0044] In the composite 20, on a side opposite the substrate 4, at the longitudinal separation plane yy', separation points 11A are created, which are provided for a targeted division of the composite 20. Furthermore, the composite 20 can be formed with further separation points 11B on a side opposite the substrate 4 along the transverse separation plane xx'. The separation points 11A, 11B are depressions in the composite 20, which enable a targeted division. The separation points 11A, 11B extend in the embodiments of the Fig. 1 to 5 and 7 to 15 extend at most into the substrate 4 and end above the structured area 8, 9.

[0045] The composite 20 is divided into a plurality of laser bars 2 at a longitudinal separation plane y-y' running between two adjacent laser bars 2. Furthermore, the separated laser bars 2 are separated into a plurality of laser diodes 1 at a transverse separation plane x-x' running between two adjacent laser diode elements 3, which extends transversely, in particular perpendicularly, to the longitudinal separation plane yy'. In particular, the composite 20 is separated by breaking at the longitudinal and transverse separation planes y-y', x-x', with the separation points 11A, 11B serving as predetermined breaking points. The separation process preferably takes place starting from the rear side of the composite 20, i.e., starting from the side of the substrate 4. The breaking process takes place, for example, as in a 3-point bending test.

[0046] By dividing the composite 20 at a longitudinal separation plane yy' running between two adjacent laser bars 2, laser facets 1C of the laser diodes 1 are formed on the laser diode elements 3. In the case of the Fig. 1 and Fig. In the embodiment shown in Figure 2A, the structured region 8 has a recess 9 that runs continuously along the longitudinal separation plane yy'. The recess 9 has a prismatic or cuboid shape (cf. Fig. 2B). Furthermore, the recess 9, as shown in Fig. 2A, in a longitudinal section arranged parallel to the longitudinal separation plane yy', the recess 9 has a rectangular shape. In particular, a depth T of the recess 9 along the longitudinal separation plane yy' does not change. The depth T can be between 1 µm and 100 µm, including the boundaries. A maximum lateral extent A of the recess 9, which is determined perpendicular to the longitudinal separation plane yy', is preferably between 0.5 µm and 50 µm, including the boundaries.

[0047] The stress distribution in the composite 20 can be advantageously influenced by the specifically introduced recess 9 or the structured area 8. This is achieved by the Fig. 2B and Fig. 3B illustrates this.

[0048] As in both Fig. 2B and Fig. 3B, the tensile stress P tstarting from a first main surface 20A of the composite 20 to a stress-free neutral area N. The compressive stress P k decreases linearly from a second main surface 20B of the composite 20 to the stress-free neutral region N. By means of the structured region 8, the neutral region N can be shifted towards the first main surface 20A. This can increase the maximum tensile stress Pt occurring at the first main surface 20A. Furthermore, this also increases the maximum compressive stress P prevailing at the second main surface 20B. kFor example, with a local reduction of the thickness D of the laser bar composite 20 by 20%, the maximum tensile stress Pt can be increased by a factor of two to ten. Increasing the maximum tensile stress Pt at the first main surface 20A has a particularly favorable effect on the dicing process and leads to improved quality of the laser facets 1C.

[0049] The Fig. 4 to 9 show further embodiments of laser bar composites 20, in which the structured regions 8, as in the first embodiment, each have only one continuously extending depression 9 through the laser bar composite 20. In contrast to the first embodiment, however, the depth of the depressions 9 varies along the longitudinal separation plane y-y'. The depressions 9 each have alternately arranged regions 9A, 9B of different depths T1, T2. In particular, the deeper regions 9B are arranged in the region of the laser diode elements 3, so that the stress conditions can be influenced specifically in the region of the laser diode elements 3.

[0050] The continuously extending depression 9 can have a composite shape. For example, the composite shape can be composed of a larger partial region 90 and a plurality of smaller partial regions 91 adjacent to the larger partial region 90. Preferably, the smaller partial region 91 follows the larger partial region 90 in a vertical direction V. In particular, the deeper regions 9B are each composed of a section of the larger partial region 90 and a smaller partial region 91, while the other regions 9A consist of a section of the larger partial region 90. For example, the larger partial region 90 can have the shape of a prism, in particular a cuboid. Furthermore, the smaller partial regions 91 can have the shape of a prism, in particular a cuboid, a pyramid, a cylinder, or a hemisphere.Preferably, the smaller subregions 91 or the deeper regions 9B each have a width B2 that is greater than a width B of the laser diode elements 3. The width B of the laser diode elements 3 or laser diodes 1 is preferably between 50 µm and 1000 µm, particularly preferably between 100 µm and 400 µm, including the boundaries. In particular, the smaller subregions 91 or deeper regions 9B are twice as wide as the laser diode elements 3 or laser diodes 1.

[0051] In the Fig. 4, Fig. 5 and Fig. 6, the shape of the recesses 9 is composed of a larger prism-shaped, in particular cuboid-shaped, partial area 90 and several smaller prism-shaped, in particular cuboid-shaped, partial areas 91. In the embodiment shown in Fig. 5, the deeper regions 9B extend in the vertical direction V up to between the separation points 11A and are therefore smaller in width B2 than in Fig. 4. This also applies to the embodiment shown in Fig. 6. Furthermore, in this embodiment, the separation points 11A extend to the structured region 8. The continuous formation of the structured region 8 with the separation points 11A can facilitate the separation of the composite 20.

[0052] In the Fig. 7 and Fig. 8, the shape of the recesses 9 is composed of a larger prism-shaped, in particular cuboid-shaped, partial area 90 and several smaller spherical partial areas 91. In the embodiment shown in Fig. 8, the deeper regions 9B have a greater depth T2 than in the embodiment shown in Fig. 7 illustrated embodiment.

[0053] In the Fig. In the embodiment shown in Figure 9, the shape of the recess 9 is composed of a larger prism-shaped, in particular cuboid-shaped, partial area 90 and several smaller pyramid-shaped or prism-shaped partial areas 91.

[0054] Fig. 10 shows a further exemplary embodiment of a laser bar composite 20, which differs from the preceding exemplary embodiments in that the structured region 8 does not have a single, but rather a plurality of separate depressions 9, wherein two adjacent depressions 9 are separated from one another by a substrate region, i.e., a region of the substrate 4. The depressions 9 have a rectangular shape in a longitudinal section arranged parallel to the longitudinal separation plane yy. The depressions 9 can have the three-dimensional shape of a prism, in particular a cuboid, or a cylinder. The depressions 9 each have a width B2 that is greater than the width B of the laser diode elements 3. The depressions 9 are arranged in the region of the laser diode elements 3, so that the stress conditions can be influenced specifically in the region of the laser diode elements 3.

[0055] In the Fig. 11 to 15 show various embodiments of laser bar composites 20 in a cross-section arranged parallel to the transverse separation plane xx'. Fig. In the embodiments illustrated in Figures 11 to 14, the structured region 8 has a polygonal shape. The polygonal shape can be rectangular (cf. Fig. 11), pentagonal (cf. Fig. 12), square (cf. Fig. 13) or triangular (cf. Fig. 14). In the Fig. In the embodiment shown in Figure 15, the structured region 8 has a semicircular shape, which, for example, resembles a semioval or a semicircle.

[0056] For each of the Fig. 2A, Fig. 4, Fig. 5, Fig. 6 and Fig. 10, a cross-sectional shape of the structured area 8 according to the embodiments of the Fig. 11 to 15. For the Fig. 7 and Fig. 8, a cross-sectional shape of the structured area 8 according to the embodiment of the Fig. 15 is also possible. Fig. 9 illustrated embodiment in particular a cross-sectional shape of the structured area 8 according to the embodiment of Fig. 12 in question.

[0057] The Fig. 16A and Fig. 16B show an embodiment of a laser diode 1, which is produced in particular by a method or from a composite according to the embodiments of the Fig. 1, Fig. 2A, Fig. 4, Fig. 5, Fig. 6, Fig. 9 and Fig. 10 can be produced.

[0058] The laser diode 1 comprises a semiconductor body 7 with a substrate 4 and a semiconductor layer sequence 5 arranged on the substrate 4, which comprises an active zone 6 suitable for generating electromagnetic radiation. Furthermore, the semiconductor layer sequence 5 has, in particular, an n-type semiconductor region 5A and a p-type semiconductor region 5B, with the active zone 6 arranged therebetween. Furthermore, the semiconductor body 7 has a first main surface 1A and a second main surface 1B opposite the first main surface 1A, and at least one first and second laser facet 1C, which are each arranged transversely to the first and second main surfaces 1A, 1B. "Transverse" means that a normal vector of the laser facets 1C does not run parallel to a normal vector of the first and / or second main surfaces 1A, 1B. The laser facets 1C each delimit the semiconductor body 7 in a lateral direction L2, -L2 (cf. Fig. 16B). The lateral directions L2, -L2 are arranged in a plane that is parallel to a main extension plane L1-L2 of the substrate 4. The first main surface 1A is preferably a surface of the semiconductor layer sequence 5 that delimits the semiconductor body 7 on a side of the active zone 6 facing away from the substrate 4. In addition to the laser facets 1C, the semiconductor body 7 has further side surfaces 1D, each of which is arranged transversely to the first and second main surfaces 1A, 1B.

[0059] The laser diode 1 has a ridge structure 15. This is arranged on the first main surface 1A, so that the first main surface 1A of the semiconductor layer sequence 5 is a surface composed of several partial surfaces. The laser diode 1 is therefore a so-called ridge waveguide laser diode, with the ridge structure 15 acting as a lateral waveguide for the emitted light. Furthermore, the laser diode 1 has a passivation layer 14 arranged between the semiconductor body 7 and the contact region 10. The passivation layer 14 is, in particular, part of the lateral waveguide. Suitable materials for the passivation layer 14 are electrically weakly or non-conductive materials, in particular silicon oxides or silicon nitrides.

[0060] The laser diode 1 has two structured facet regions 13, each located at the transition between the second main surface 1B and one of the two laser facets 1C. The structured facet region 13 has a recess 12 in each case. In the region of the recess 12, the semiconductor body 7 has a reduced thickness. The recesses 12 are formed during the division of various depressions in the laser bar composite.

[0061] The structured facet regions 13 each extend parallel to an edge of the semiconductor body 7, which edge is located at the transition between the second main surface 1B and the laser facet 1C. In the illustrated embodiment, the indentations 12 each extend over the entire width B of the laser diode 1. The indentations 12 preferably have a first lateral dimension A1 between 50 µm and 1000 µm, particularly preferably between 100 µm and 400 µm, the boundaries being included. The first lateral dimension A1 is determined parallel to the first lateral direction L1. Furthermore, the indentations 12 have a second lateral dimension A2, which is determined parallel to the second lateral direction L2. The second lateral dimension A2 preferably corresponds to half the lateral dimension A of the structured region 8 (cf. Fig.2B). The indentations 12 preferably have a second lateral dimension A2 of 0.25 to 25 µm, including the boundaries. The laser diode 1 has a second lateral dimension A2' of 600 to 1200 µm, with possible deviations of 10%.

[0062] The indentations 12 are limited to the substrate area and do not extend to the active zone 4. The laser diode 1 thus remains unstructured in the area of the active zone 4. The indentations 12 have a uniform depth T. The depth T can be between 1 µm and 100 µm, including the boundaries.

[0063] The indentations 12 have a polygonal or rectangular shape both in a cross-section arranged parallel to the laser facets 1C and in a longitudinal section running perpendicular to the laser facets 1C.

[0064] The laser diode 1 is preferably an edge emitter. During operation, laser radiation is emitted from one of the laser facets 1C parallel to a normal vector of the laser facet 1C.

[0065] The invention is not limited by the description based on the exemplary embodiments. Rather, the invention encompasses any novel feature and any combination of features, including, in particular, any combination of features in the patent claims, even if this feature or combination itself is not explicitly stated in the patent claims or exemplary embodiments.

[0066] This patent application is a divisional application of the German patent application 102017117136.3, the disclosure content of which is hereby incorporated by reference. List of reference symbols 1 laser diode 1A first main area 1B second main area 1C laser facet 1D side surface 2 laser bars 3 laser diode element 4 Substrat 5 Semiconductor layer sequence 6 active zones 7 semiconductor bodies 8 structured area 9 Deepening 9A, 9B Area of the depression 90, 91 Part of the deepening 10 Contact area 11A, 11B Separation point 12 indentation 13 structured facet area 14 Passivation layer 15 Bridge structure 20 laser bar composite 20A first main area 20B second main area A, A1, A2, A2' lateral dimension B, B2 width D Thickness H Main direction of extension L1, L2 lateral direction N neutral area P t tensile stress P k compressive stress T, T1, T2 depth V vertical direction X - X' cross-section plane Y - Y' longitudinal separation plane

Claims

[1] Method for producing a plurality of laser diodes (1) with the following method steps: - Providing a plurality of laser bars (2) in the composite (20), wherein the laser bars (2) each comprise a plurality of laser diode elements (3) arranged next to one another, and the laser diode elements (3) have a common substrate (4) and each have a semiconductor layer sequence (5) arranged on the substrate (4), and wherein a division of the composite (20) at a respective longitudinal separation plane (y-y') running between two adjacent laser bars (2) leads to a formation of laser facets (1C) of the laser diodes (1) to be produced, - Structuring the composite (20) on at least one longitudinal separation plane (y-y'), wherein a structured region (8) is produced in the substrate (4), and the structured region (8) has a depression (9) running continuously along the longitudinal separation plane (y-y'), wherein the continuously running depression (9) has a composite shape which is composed of a larger partial region (90) and a plurality of smaller partial regions (91) adjoining the larger partial region (90), wherein the smaller partial region (91) follows the larger partial region (90) in a vertical direction (V), and wherein the smaller partial regions (91) each have a width (B2) which is greater than a width (B) of the laser diode elements (3), and wherein the structured region (8) extends into the substrate (4) starting from a surface of the substrate (4) facing away from the semiconductor layer sequence (5). [2] Method according to the preceding claim, wherein the structured region (8) ends in the substrate (4). [3] Method according to claim 1, wherein the structured region (8) extends through the substrate (4) and completely penetrates the substrate (4). [4] Method according to one of the preceding claims, wherein the continuously extending recess (9) has alternately arranged regions (9A, 9B) of different depths (T1, T2) along the longitudinal separation plane (y-y'). [5] Method according to the preceding claim, wherein the deeper regions (9B) each have a width (B2) which is greater than a width (B) of the laser diode elements (3). [6] Method according to one of the two preceding claims, wherein the deeper regions (9B) are each composed of a section of the larger partial region (90) and a smaller partial region (91). [7] Method according to the preceding claim, wherein the other regions (9A) consist of a section of the larger partial region (90). [8] Method according to one of the preceding claims, wherein the larger partial region (90) has the shape of a prism or cuboid. [9] Method according to any preceding claim, wherein the smaller subregions (91) have the shape of a prism, a cuboid, a pyramid, a cylinder or a hemisphere. [10] Method according to one of the preceding claims, wherein the structuring is carried out by means of laser etching. [11] Method according to one of the preceding claims, wherein the separation of the composite (20) into a plurality of laser diodes (1) is carried out by breaking the composite (20) at the longitudinal separation planes (y-y') and transverse separation planes (x-x') extending transversely to the longitudinal separation planes (y-y'). [12] Method according to one of the preceding claims, wherein in the composite (20) on a side opposite the substrate (4) at the longitudinal separation plane (y-y') separation points (11A) are produced, which are provided for a targeted division of the composite (20).

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