Laser device and method for producing laser device

Abstract

The invention relates to a laser device comprising an edge-emitting semiconductor laser chip having an active region and a laser facet adjoining the active region, and an optical element which is arranged downstream of the laser facet in the emission direction of the edge-emitting semiconductor laser chip. The front side of the edge-emitting semiconductor laser chip and the optical element are connected to each other by means of a solder connection that does not contain a solder additive, and the laser facet is retracted relative to the front side.

Description

[0001] This application claims priority to German patent application 10 2023 121 985.5, filed August 16, 2023, the disclosure of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The invention relates to a laser device and to a method for producing a laser device. BACKGROUND

[0003] Known semiconductor lasers, in particular semiconductor lasers which emit blue light, generally require a hermetically sealed package in order to protect the laser facet from which the laser light is emitted from organic substances, since organic substances in the region of the laser facet can lead to ageing phenomena and to degradation over a longer period of time. Organic substances accumulate at the laser facet and absorb light power when the semiconductor laser is in operation. The light output power of the laser is thereby reduced. When the absorption exceeds a certain threshold, the laser facet is damaged. The semiconductor laser is then unusable. Such semiconductor lasers are therefore generally constructed in a hermetically sealed housing in order to prevent organic substances from accumulating at the laser facet. However, the production of such hermetically sealed housings is costly and expensive.

[0004] There is therefore a need to provide a laser device with which at least one of the above aspects can be overcome. Furthermore, there is also a need to provide a method for producing such a laser device. SUMMARY

[0005] The above needs are met by the subject-matter of the independent claims. Improved forms and design forms of the proposed principle are specified in the dependent claims.

[0006] The core of the invention is to provide a laser device which, in particular, does not require a hermetically sealed package and is still constructed ageing-stable. To this end, an optical element is arranged in a region in front of a laser facet of a semiconductor chip, wherein the spacing between the laser facet and the optical element is so small that organic substances cannot or hardly get into the intermediate space between the laser facet and the optical element. By means of a high-focusing laser, the joining surface between the optical element and the semiconductor chip is melted, thereby connecting the optical element to the semiconductor chip. Here, the connection is in particular made by means of a direct laser welding process, by which the optical element is welded onto the semiconductor chip. Here, the semiconductor chip is in particular constructed such that it comprises an etched laser facet which is set back with respect to the front side of the semiconductor chip. By applying a photoelectrochemical separation process of the semiconductor laser chip, a relatively small spacing can be achieved between the separation edge / front side and the etched laser facet, so that the optical element can be welded onto the front side very close to the laser facet.

[0007] Advantages that can be achieved relative to the state of the art include, but are not limited to, being able to be: - no hermetic encapsulation / housing is required.

[0008] - no organic adhesive is required to affix the optical element to the semiconductor chip.

[0009] - by means of a photoelectrochemical separation process of the semiconductor laser chip, a relatively small spacing can be achieved between the separation edge / front side and the etched laser facet, so that the optical element can be soldered very close to the laser facet onto the front side.

[0010] - when no hermetic encapsulation and / or organic adhesive is required, it is cost-advantageous.

[0011] - when the optical element can be close to the laser facet and / or no organic adhesive is required, there is a reliability advantage.

[0012] - when the optical element can be close to the laser facet and / or no organic adhesive is required, there is an improved aging stability.

[0013] A laser device is provided. The laser device generates electromagnetic radiation, in particular laser radiation, in operation. The laser device is designed to generate electromagnetic radiation having a wavelength, for example, in the wavelength range between infrared radiation and ultraviolet radiation. In particular, the electromagnetic radiation can lie in the wavelength range of the infrared radiation and / or the ultraviolet radiation.

[0014] According to at least one embodiment of the laser device, the laser device comprises a semiconductor laser chip. The semiconductor laser chip can in particular be an edge-emitting semiconductor laser chip. However, it is also conceivable that the semiconductor laser chip is formed by a surface-emitting semiconductor laser chip.

[0015] The semiconductor laser chip comprises, for example, a semiconductor body, a reflective outer face forming a resonator, and an electrical connection site for contacting the semiconductor laser chip.

[0016] The semiconductor laser chip comprises a laser facet. Laser radiation generated by the semiconductor laser chip in operation exits at the laser facet. The laser facet is formed, for example, by a recessed outer face of the semiconductor laser chip with respect to a front side, for example, by a recessed side face or top face.

[0017] The semiconductor laser chip comprises an active region, which comprises a region of the laser facet at which the electromagnetic radiation generated in operation exits the semiconductor laser chip. For example, in the region of the active region, an active layer of the semiconductor laser chip adjoins a reflective layer of the semiconductor laser chip, which is part of a resonator of the semiconductor laser chip.

[0018] According to at least one embodiment of the laser device, the laser device comprises an optical element which is arranged downstream of the semiconductor laser chip at the laser facet. The optical element follows the laser facet of the semiconductor laser chip, in particular in the emission direction of the semiconductor laser chip.

[0019] It is thereby possible for all or at least a large proportion of the laser radiation which leaves the semiconductor laser chip to pass through the optical element and to be optically influenced by the optical element.

[0020] The optical element is for example an optical element for beam shaping by means of optical refraction. For example, the optical element can then be a lens for focusing the laser radiation. It is alternatively or additionally possible for the optical element to be a diffractive optical element (DOE), wherein the beam shaping is based on the optical diffraction principle.

[0021] The optical element is formed from a material which is permeable to laser radiation, i.e. for example glass, semiconductor material and / or plastic material. The optical element can for example also be formed by a ceramic or comprise a ceramic material, i.e. for example ZrO or SiN.

[0022] A gap is at least locally formed between the optical element and the laser facet, which gap is for example filled with air or another medium. Here, the gap is in particular so small that organic substances cannot or hardly enter the intermediate space between the laser facet and the optical element.

[0023] According to at least one embodiment of the laser device, the semiconductor laser chip and the optical element are connected to one another by means of a solder connection. Here and in the following, the solder connection is immediately a mechanical connection which is produced between the two joining partners of the laser device under the action of heat and / or pressure and which cannot be detached without damage.

[0024] Here, the solder connection is in particular free of solder additives. That is to say, the solder connection is formed only by the materials of the joining partners which are connected to one another by means of the solder connection. The joining partners are thus connected directly to one another without additional connection materials such as solder additives or adhesives.

[0025] According to at least one embodiment of the laser device, the laser device comprises an edge-emitting semiconductor laser chip which has an active region and a laser facet which adjoins the active region, and an optical element which is arranged downstream of the laser facet in the emission direction of the edge-emitting semiconductor laser chip. Here, the front side of the edge-emitting semiconductor laser chip and the optical element are connected to one another by means of a solder connection which is free of solder additives, and the laser facet is set back relative to the front side.

[0026] The laser device comprises, but is not limited to, the following considerations. In semiconductor laser devices, for example, which are operated at open atmosphere, a deposition of foreign matter at the laser facet is observed, which deposition leads to a degradation of the laser device, for example, due to a drop in optical power. Here, the deposition can take place due to dust or aerosols in the surrounding air.

[0027] Now, the described laser device is based on the idea that arranging the optical element particularly close to the laser facet reduces, suppresses and / or prevents a deposition of foreign matter from the surrounding atmosphere. Here, the use of a solder connection allows the omission of a connecting material, which enables a particularly economical manufacture of the laser device. Furthermore, no optimization of other materials, for example, the connecting material, with regard to their optical and / or thermal properties is necessary, which in turn allows a particularly simple and economical manufacture.

[0028] This possibility is also offered by the described laser device for semiconductor laser chips with etched laser facets, since especially known semiconductor laser chips with etched laser facets have a relatively large spacing between the front side of the semiconductor laser chip and the laser facet. This large spacing is caused, in particular, by a multi-step etching process, by means of which the laser facet is etched and the semiconductor chip is separated on the one hand, and which is a problem in known semiconductor chips, since the optical element cannot be arranged sufficiently close in front of the laser facet in order to achieve the desired effect of improved aging stability. For example, the large spacing can occur in the form of a step, which occurs by a combined dry and wet etching, i.e. an actual facet release, and by a second etching step, i.e. a dry etching, which ensures a safety spacing from the component side / front side in order to subsequently separate the semiconductor laser chip by means of dicing and cleaving or by means of a laser cutting process. In known semiconductor chips, in particular, this second step (about 20 pm) creates a particularly large spacing between the laser facet and the component side / front side of the semiconductor chip, since for the above-mentioned separation techniques a large safety spacing is necessary in order to protect the laser facet.

[0029] However, it is now proposed that the second etching for the separation and / or in a combined manner for the facet release is realized by means of a further process, thus, for example, by means of a photoelectrochemical process. This photoelectrochemical process allows a clean and smooth cutting of the substrate of the semiconductor chip. By means of this photoelectrochemical process, it is possible to reduce the spacing between the laser facet and the component side / front side of the semiconductor chip to very small values, up to 2 pm, so that the optical element applied to the front side has a correspondingly small spacing from the laser facet. Experience shows that with such a small gap between the laser facet and the optical element, a significant reduction in the degradation of the laser facet by organic substances is possible.

[0030] According to at least one embodiment of the laser device, the spacing between the optical element and the laser facet is at most 10 pm, in particular at most 7 pm or at most 1 pm. Spacings of 500 nm and less are also possible. In particular, the minimum spacing between the optical element and the laser facet is in the region of the active region. It has been shown here that such small spacings ensure that the accumulation of foreign bodies from the atmosphere at the laser facet is greatly reduced or prevented.

[0031] According to at least one embodiment of the laser device, the solder connection comprises a solder seam and / or a solder point, which extends in the connection region between the optical element and the front side of the semiconductor chip and comprises the material of the optical element and of the semiconductor chip. The solder seam or solder point can be configured in any shape and size. According to at least one embodiment of the laser device, the solder connection comprises a plurality of solder seams and / or a solder point.

[0032] According to at least one embodiment of the laser device, the solder connection is arranged between the optical element and the semiconductor laser chip. It is in particular possible that the solder connection between the optical element and the semiconductor laser chip is the only connection between these two components of the laser device. The solder connection establishes a direct physical contact between the optical element and the semiconductor laser chip. In particular, the connection between the optical element and the semiconductor chip is free of additional connection material.

[0033] According to at least one embodiment of the laser device, the solder connection comprises a solder seam or a solder point. The solder seam or solder point connects the components to one another in material fit at the solder joint. The solder joint is understood to be the region in which the components merge into one another. In particular, the solder seam is a solder connection along a connection line or connection curve, and the solder point is a solder connection in a planar or point-like region. Here, the components are connected to one another in material fit only along the connection line or connection curve or in the planar or point-like region. In other words, the solder seam or solder point is spatially limited to the region of the components in which the components are connected to one another. The solder seam does not connect the components over the entire face directed towards one another, in particular does not connect planarly.

[0034] According to at least one embodiment of the laser device, the solder connection is configured planarly and connects the components over the entire face directed towards one another, in particular connects planarly.

[0035] According to at least one embodiment, the solder seam does not connect the optical element and the semiconductor laser chip planarly. In other words, the solder seam is arranged in a spatially limited region between the optical element and the semiconductor laser chip, for example along a line or curve or in a point. The solder seam can for example comprise a plurality of concentrically extending curves and / or meandering curves, which are for example arranged between the optical element and the semiconductor laser chip in a zigzag pattern. In this way it is possible to produce a connection between the two components that is as planar as possible.

[0036] According to at least one embodiment, the soldered connection comprises material of the optical element and / or of the semiconductor laser chip. In particular, the soldered connection can be produced in that material of the optical element and of the semiconductor laser chip is melted in a predefined contact area, mixed and then solidified again, so that a firm connection of the optical element to the semiconductor laser chip is formed in this predefined area.

[0037] According to at least one embodiment, the semiconductor laser chip comprises at least one step, wherein a first face of the at least one step forms the front side and a second face of the step, which extends essentially parallel to the first face, comprises the laser facet. Here, the perpendicular distance between the first face and the second face can be at most 10 pm, in particular. It is also possible for two or more steps to be formed between the first face and the second face, wherein the distance between the two most distantly spaced apart essentially parallel faces of the steps is at most 10 pm, in particular.

[0038] According to at least one embodiment, the semiconductor laser chip comprises exactly one step, wherein a first face of the one step forms the front side and a second face of the one step, which extends essentially parallel to the first face, comprises the laser facet. Here, the perpendicular distance between the first face and the second face can be at most 10 pm, in particular.

[0039] According to at least one embodiment, the height of the at least one step is chosen such that the light cone emitted by the edge-emitting semiconductor laser chip from the laser facet does not intersect the edge-emitting semiconductor laser chip. In particular, the total height of all steps present is chosen such that the light cone emitted by the edge-emitting semiconductor laser chip from the laser facet does not intersect the edge-emitting semiconductor laser chip. By dimensioning of the step(s), in particular, it is to be prevented that the light cone emitted by the edge-emitting semiconductor laser chip from the laser facet intersects the edge-emitting semiconductor laser chip, so that a so-called “cut-off” of the light cone is obtained, while keeping the distance between the front side and the laser facet small.

[0040] According to at least one embodiment, the height of the at least one step corresponds at least to half of the half-axis of the light cone emitted by the edge-emitting semiconductor laser chip from the laser facet in the area of the front side. In particular, the total height of all steps present corresponds at least to half of the half-axis of the light cone emitted by the edge-emitting semiconductor laser chip from the laser facet in the area of the front side. By dimensioning of the step(s), in particular, it is to be prevented that the light cone emitted by the edge-emitting semiconductor laser chip from the laser facet intersects the edge-emitting semiconductor laser chip, so that a so-called “cut-off” of the light cone is obtained, while keeping the distance between the front side and the laser facet small.

[0041] According to at least one embodiment, a substantially light-impermeable or reflective layer is arranged between the front side and the optical element. The light-impermeable or reflective layer can in particular be a regional coating of the optical element and / or of the front side. In particular, the solder connection can also comprise a material of the light-impermeable or reflective layer. For example, the light-impermeable or reflective layer can be designed in such a way that it particularly well absorbs the light used in the soldering process and leads to an improved soldering result. A further effect of the light-impermeable or reflective layer can be to interrupt the light path between the semiconductor laser chip and the optical element in the region of the front side.

[0042] According to at least one embodiment, a potting compound, in particular a silicone or polysiloxane potting compound, is arranged in the gap between the optical element and the laser facet. In particular, the gap between the optical element and the laser facet can be completely filled with the potting compound. The aging stability of the laser device can thereby also be further improved, since the risk of the presence of organic substances in the region of the laser facet is further reduced.

[0043] According to at least one embodiment of the laser device, the laser device has no hermetically sealed housing. That is to say, the laser device can for example comprise a non-hermetically sealed housing, or the laser device has no housing at all, and the components of the laser device are arranged together on for example a carrier of the laser device.

[0044] The omission of a hermetically sealed housing is in particular possible due to the arrangement of the optical element at a small distance from the laser facet and allows a particularly compact and economical laser device to be produced.

[0045] The semiconductor laser chip can for example comprise a reflective layer at least at the laser facet, which comprises a metal oxide and / or a semiconductor oxide. The reflective layer then forms part of the semiconductor laser chip resonator. The reflective layer can extend over the entire outer / upper side of the semiconductor laser chip, wherein in particular at least the front side of the semiconductor laser chip is free of the reflective layer. It is however also possible for the solder connection to be formed at least in sections with the material of the optical element and the material of the reflective layer. The reflective layer can for example comprise silicon dioxide.

[0046] According to at least one embodiment of the laser device, the semiconductor laser chip comprises a gallium nitride (GaN) substrate and / or is largely composed of GaN. It is however also possible for the semiconductor chip to comprise or to be composed of other semiconductor materials, for example silicon. Other possible materials for at least one substrate of the semiconductor chip can be sapphire, aluminum nitride or gallium arsenide.

[0047] According to at least one embodiment of the laser device, the laser device comprises a carrier or carrier substrate. The remaining components of the laser device, in particular the semiconductor laser chip, are fixed on the carrier. Here, the carrier substrate can serve for electrical actuation, mechanical fixation and / or as a heat sink for the laser device. Furthermore, a pedestal can be arranged between the semiconductor laser chip and the carrier substrate, which forms a riser for the semiconductor laser chip in order to prevent a so-called "cut-off" of the light cone emitted from the laser facet by the carrier substrate from the edge-emitting semiconductor laser chip.

[0048] According to at least one embodiment, the optical element is arranged spaced apart from the carrier substrate, and wherein in particular the optical element is arranged spaced apart from the pedestal. In particular, the optical element is only in contact with the semiconductor laser chip. Thereby, it can be prevented that stresses occurring between the components in the laser device can lead to a detachment of the optical element.

[0049] A method for producing a laser device is also proposed. By means of the method, inter alia, the laser device described herein can be produced. That is, all features disclosed for the laser device also apply to the method and vice versa.

[0050] According to at least one embodiment of the method, an edge-emitting semiconductor laser chip is first provided, which has an active region and a laser facet adjoining the active region.

[0051] According to at least one embodiment of the method, an optical element is provided. The optical element is arranged at the laser facet at the front side of the edge-emitting semiconductor laser chip downstream of the laser facet in the emission direction of the edge-emitting semiconductor laser chip.

[0052] According to at least one embodiment of the method, in a further method step, the front side of the semiconductor laser chip is connected with the optical element in a connection region by means of a soldering process, wherein the soldering process is carried out without the use of a soldering additive.

[0053] According to at least one embodiment of the method, the laser facet is set back with respect to the front side of the semiconductor laser chip.

[0054] According to at least one embodiment of the method, the method comprises the following steps: providing an edge-emitting semiconductor laser chip, which has an active region and a laser facet adjoining the active region; providing an optical element; arranging the optical element at the front side of the edge-emitting semiconductor laser chip downstream of the laser facet in the emission direction of the edge-emitting semiconductor laser chip; and connecting the front side and the optical element by means of a soldering process, wherein the soldering process is carried out without the use of a soldering additive; wherein the laser facet is retracted with respect to the front side.

[0055] Here, the semiconductor laser chip and the optical element can be connected to each other directly at the interface between the front side of the semiconductor laser chip and the optical element by means of a soldering process.

[0056] According to at least one embodiment of the method, connecting the semiconductor laser chip and the optical element in the connection region by means of a soldering process comprises producing a solder joint or a solder spot. In particular, the solder joint or solder spot between the optical element and the semiconductor laser chip is the only connection between these two components of the laser device. In particular, the connection between the optical element and the semiconductor chip is free of additional connection material.

[0057] According to at least one embodiment of the method, the solder joint or solder spot is not produced between the optical element and the semiconductor laser chip in an area- wise manner. In particular, the solder joint or solder spot is produced in a spatially limited region between the optical element and the front side of the semiconductor laser chip, for example along a line or a curve or only in one point.

[0058] According to at least one embodiment of the method, the soldering process is carried out by means of a laser beam which is focused in the region between the front side and the optical element. To this end, for example, the laser beam is guided through the optical element and focused at the interface between the components to be connected. As a result, a region of high power density is formed at the interface, in which the joining partners are locally melted. The laser beam is then moved, for example, along a curve, so that a solder joint is formed by means of the joining partner material.

[0059] To this end, for example, soldering peaks as are offered by the company Primoceler for connecting glass can be used. Of course, it is also possible to use alternative laser soldering peaks. For example, it is also conceivable to use friction soldering peaks for producing the soldered connection or to use an anodic bonding, which according to the present description is also to be understood as falling within the scope of soldering peaks. BRIEF DESCRIPTION OF DRAWINGS

[0060] Various embodiments and examples, which are described in detail in connection with the accompanying drawings, disclose further aspects and embodiments in accordance with the proposed principles.

[0061] Figure 1 A cross-sectional view of a laser device is shown according to some aspects of the proposed principles; Figure 2 A cross-sectional view of another embodiment of a laser device is shown according to some aspects of the proposed principles; Figure 3 A cross-sectional view of another embodiment of a laser device is shown according to some aspects of the proposed principles; Figure 4a sectional view of a further embodiment of a laser device according to aspects of the proposed principles is shown; Figure 5 a sectional view of a further embodiment of a laser device according to aspects of the proposed principles is shown; Figure 6 a sectional view of a further embodiment of a laser device according to aspects of the proposed principles is shown; and Figure 7 a sectional view of a further embodiment of a laser device according to aspects of the proposed principles is shown; and DETAILED DESCRIPTION

[0062] The following embodiments and examples demonstrate different aspects according to the proposed principles and combinations thereof. The embodiments and examples are not necessarily drawn to scale. Likewise, different elements can be exaggerated or minimized in order to emphasize certain aspects. It will be apparent that various aspects and features of the illustrated embodiments and examples can be combined with each other and the principles of the present invention. Some aspects have regular or repeating structures or forms. It is to be noted that slight variations of the ideal forms can occur in actual applications and these variations are not to be regarded as being outside the scope of the present invention.

[0063] Furthermore, the various graphs, features and aspects are not necessarily shown to scale and the scale between various elements can not be entirely correct. Certain aspects and features are emphasized by exaggeration. However, terms like "upper", "above", "lower", "below", "larger", "smaller" and the like are correctly indicated between elements in the graphs. Thus, such relationships between elements can be derived from the graphs.

[0064] Figure 1 A schematic diagram shows a sectional view of a laser device 100. The laser device 100 comprises an edge-emitting semiconductor laser chip 1 and an optical element 2 which is fixed at a front side 4 of the semiconductor laser chip 1 by means of a solder connection 3.

[0065] The semiconductor laser chip 1 comprises an active region 11 and a laser facet 1a adjoining the active region, from which the semiconductor laser chip 1 emits laser light L in operation of the laser device 100. Here, the semiconductor chip 1 is designed such that the laser facet 1a is set back with respect to the front side 4 and is thus spaced apart from the front side 4 by a distance d. This can in particular result from the use of an etching process for producing the laser facet 1a in the manufacture of the semiconductor laser chip 1, by means of which an etching step 9 having a height h and a depth d is etched in the semiconductor laser chip 1. A first face 10a is formed by the etching step 9, which forms the front side 4 and a second face 10b extending substantially parallel to the first face 10a, which second face comprises the laser facet 1a.

[0066] Arranging or fixing the optical element 2 at the first face 10a or front side 4 leads to the fact that the optical element 2 is arranged downstream of the laser facet la and spaced apart from the laser facet la by a distance d in the emission direction of the edge-emitting semiconductor laser chip 1 which, in the case shown, corresponds to the depth of the step 9.

[0067] Here, the dimensions d and h of the step 9 are chosen such that the accumulation of foreign matter from the atmosphere at the laser facet is substantially reduced or prevented and such that the light cone emitted by the edge-emitting semiconductor laser chip from the laser facet does not intersect the edge-emitting semiconductor laser chip, i.e. a so-called "cut-off" of the light cone is not produced.

[0068] The optical element 2 and the semiconductor laser chip are connected to each other at the front side 4 of the edge-emitting semiconductor laser chip 1 by means of a solder connection 3 which does not contain solder additives. Here, the solder connection 3 can be formed in particular by a solder joint or solder point and only comprises the materials of the optical element 2 and of the semiconductor laser chip 1.

[0069] Figure 2 A sectional view of a further embodiment of a laser device according to some aspects of the proposed principles is shown. In addition to the embodiment shown Figure 1 The semiconductor laser chip 1 comprises a reflective layer 12 which comprises a metal oxide and / or a semiconductor oxide, in addition to the embodiment shown. The reflective layer 12 constitutes part of the resonator of the semiconductor laser chip 1. The reflective layer can extend over the entire upper side of the semiconductor laser chip, wherein the front side 4 of the semiconductor laser chip 1 is free of the reflective layer 12. In the case shown, the reflective layer 12 extends over the upper side of the semiconductor laser chip and via the step 9 up to the optical element 2. The front side 4 of the semiconductor laser chip 1 can in particular be free of the reflective layer 12, since a separation process can be carried out along the front side 4 when manufacturing the semiconductor chip 1, for example after coating with the reflective layer 12.

[0070] Figure 3 A sectional view of a further embodiment of a laser device according to some aspects of the proposed principles is shown. In addition to the embodiment shown Figure 1 The laser device 100 comprises a carrier substrate 8 on which the semiconductor laser chip 1 is fixed, in addition to the embodiment shown. Here, the carrier substrate 8 can be used for electrical actuation, mechanical fixing and / or as a heat sink for the laser device 100. Furthermore, a pedestal 16 is arranged between the semiconductor laser chip 1 and the carrier substrate 8, which forms a step-up of the semiconductor laser chip 1 in order to prevent a so-called "cut-off" of the light cone L emitted by the edge-emitting semiconductor laser chip from the laser facet through the carrier substrate 8.

[0071] The optical element 2 is arranged spaced apart from the carrier substrate 8 and spaced apart from the base 16. In particular, the optical element 2 is in contact only with the semiconductor laser chip 2. Thereby, it is possible to prevent that stresses occurring between the components in the laser device 100 can lead to a detachment of the optical element 2.

[0072] Figure 4 A sectional view of a further embodiment of a laser device according to some aspects of the proposed principles is shown. In particular, Figure 4 It is shown how to eliminate substrate modes that can be emitted from the front side 4 of the semiconductor laser chip 1 and that can cause disturbances in visualization applications. For this purpose, a light-impermeable or reflective layer 13 is applied to the optical element 2 before it is soldered to the front side. Here, the layer 13 is either absorptive or reflective to the laser radiation L to block the optical path from the front side 4 into the optical element 2.

[0073] Figure 5 A sectional view of a further embodiment of a laser device according to some aspects of the proposed principles is shown. Figure 5 An embodiment with a potting 15 is shown that fills the gap 14 between the optical element 2 and the laser facet la. Thereby, by filling the air gap between the laser facet la and the optical element 2, an additional protection of the laser facet la is achieved. The potting 15 can in particular be a high-temperature-resistant and in particular UV-resistant material, such as a silicone.

[0074] Figure 6 A sectional view of a further embodiment of a laser device according to some aspects of the proposed principles is shown. In contrast to Figure 1 In contrast to the embodiment shown, the semiconductor laser chip 1 has not only one step 9, but a first and a second step 9a, 9b. The first and the second step have a height hi, h2 and a depth di, d2, respectively, wherein the total depth d and the total height h are configured such that the accumulation of foreign matter from the atmosphere at the laser facet is substantially reduced or prevented and such that the light cone L emitted from the laser facet by the edge-emitting semiconductor laser chip does not intersect with the edge-emitting semiconductor laser chip, i.e. a so-called "cut-off" of the light cone is not produced.

[0075] While one or two steps are exemplarily shown in the figures, by which the laser facet la is set back with respect to the front side 4, it is also possible that the laser facet la is set back with respect to the front side 4 by more than two steps or that the laser facet la is set back with respect to the front side 4 in a corresponding manner by differently shaped notches.

[0076] In conjunction with the schematic diagram of Figure 1 a further embodiment of the method described here is set forth. Figure 7

[0077] ​In the method, first a semiconductor laser chip 1 is provided. The semiconductor laser chip 1 is for example an edge-emitting or surface-emitting semiconductor laser chip. The semiconductor laser chip comprises a laser facet 1a through which laser radiation L generated in the semiconductor laser chip 1 exits the semiconductor laser chip in operation.

[0078] As shown in Figure 2 At the laser facet 1a, for example, a reflective layer 12 is formed. The reflective layer 12 forms part of a resonator of the semiconductor laser chip 1. The reflective layer 12 for example comprises metal oxides and / or semiconductor oxides, which are in particular layers of different refractive indices arranged alternately.

[0079] For example, the outermost layer of the reflective layer can be formed by means of a material such as silicon dioxide.

[0080] Furthermore, an optical element 2 is provided. The optical element 2 can be provided for beam shaping of the laser radiation, which can for example take place by refraction and / or diffraction. The optical element 2 is for example formed by means of glass.

[0081] The optical element 2 is arranged at the front side 4 of the semiconductor laser chip 1 as close as possible to the laser facet 1a receding relative to the front side 4, so that the spacing d between the laser facet and the optical element 2 is at most 10 pm, in particular at most 7 pm.

[0082] Furthermore, a laser 5 is provided, which generates a laser beam 7. Via optical means 6, for example, the laser beam 7 is focused onto the interface between the optical element 2 and the front side 4 of the semiconductor laser chip 1, so that a soldered connection 3 is formed in the connecting region of the optical element 2 and the front side 4 after solidification of the molten material.

[0083] List of reference signs

[0084] 1 semiconductor laser chip

[0085] 1a laser facet

[0086] 11 active region

[0087] 12 reflective layer

[0088] 2 optical element

[0089] 3 soldered connection

[0090] 5 laser

[0091] 6 optical means

[0092] 7 laser beam

[0093] 8 carrier

[0094] 9, 9a, 9b step

[0095] 10a, 10b face

[0096] 14 gap

[0097] 15 potting compound

[0098] 16 base

[0099] d distance

[0100] h height

[0101] L light cone

Claims

1. A laser device (100) comprising: An edge-emitting semiconductor laser chip (1), the semiconductor laser chip having an active region (11) and a laser prism (1a) adjacent to the active region; and Optical element (2), which is arranged downstream of the laser prism (1a) in the emission direction of the edge-emitting semiconductor laser chip (1); in, The front side (4) of the edge-emitting semiconductor laser chip (1) and the optical element (2) are connected to each other by means of a welding connection (3) without welding additives; and The laser prism (1a) is recessed relative to the front side (4).

2. The laser device according to the preceding claim, wherein, The distance (d) between the optical element (2) and the laser prism (1a) is at most 10µm, and more particularly at most 7µm.

3. The laser device according to any one of the preceding claims, wherein, The welded connection (3) includes a weld or a weld point.

4. The laser device according to any one of the preceding claims, wherein, The welded connection (3) includes the materials of the optical element (2) and the semiconductor laser chip (1).

5. The laser device according to any one of the preceding claims, wherein, The semiconductor laser chip (1) has at least one step (9, 9a, 9b), wherein a first face (10a) of at least one step (9) forms the front side (4), and a second face (10b) of at least one step (9) extending substantially parallel to the first face (10a) includes the laser facet (1a).

6. The laser device according to any one of the preceding claims, wherein, The semiconductor laser chip (1) has exactly one step (9), wherein the first face (10a) of the step (9) forms the front side (4), and the second face (10b) of the step (9) extending substantially parallel to the first face (10a) includes the laser facet (1a).

7. The laser device according to any one of claims 5 or 6, wherein, The height (h) of at least one of the steps (9) is selected such that the light cone (L) emitted from the edge-emitted semiconductor laser chip (1) from the laser facet (1a) does not intersect with the edge-emitted semiconductor laser chip (1).

8. The laser device according to any one of claims 5 or 6, wherein, The height (h) of at least one of the steps (9) corresponds at least to half of the half-axis of the light cone (L) emitted from the laser facet (1a) of the semiconductor laser chip (1) emitted from the edge in the region of the front side (4).

9. The laser device according to any one of the preceding claims, wherein, A substantially opaque or reflective layer (13) is arranged between the front side (4) and the optical element (2).

10. The laser device according to the preceding claim, wherein, A potting compound (15), particularly a silicone potting compound or a polysiloxane potting compound, is arranged in the gap (14) between the optical element (2) and the laser prism (1a).

11. The laser device according to any one of the preceding claims, wherein the laser device does not have a hermetically sealed housing.

12. The laser device according to any one of the preceding claims, wherein, The semiconductor laser chip (1) has a reflective layer (12) at the laser facet (1a), the reflective layer particularly comprising metal oxide and / or semiconductor oxide.

13. The laser device according to any one of the preceding claims, wherein, The semiconductor laser chip (1) includes a GaN substrate.

14. The laser device according to any one of the preceding claims, wherein, The semiconductor laser chip (1) is disposed on a carrier substrate (8), and a base (16) is disposed particularly between the semiconductor laser chip (1) and the carrier substrate (8).

15. The laser device according to the preceding claim, wherein, The optical element (2) is arranged spaced apart from the carrier substrate (8), and wherein the optical element (2) is arranged in particular spaced apart from the base (16).

16. A method for manufacturing a laser device, the method comprising the following steps: A semiconductor laser chip (1) with edge emission is provided, the semiconductor laser chip having an active region (11) and a laser prism (1a) adjacent to the active region. Provide optical components (2); The optical element (2) is arranged in the emission direction of the edge-emitting semiconductor laser chip (1) downstream of the laser facet (1a) at the front side (4) of the edge-emitting semiconductor laser chip (1); as well as The front side (4) and the optical element (2) are connected by a welding process, wherein the welding process is performed without welding additives. The laser prism (1a) is recessed relative to the front side (4).

17. The method according to the preceding claim, wherein, The welding process is carried out by means of a laser beam (7), which is focused in the area between the front side (4) and the optical element (2).

18. The method according to the preceding claim, wherein, The material in the region between the front side (4) and the optical element (2) is melted, and the material forms a welded joint (3) after solidification.

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