Micro-thin-layer surface emitter

Abstract

The invention relates to a surface emitter, having: a first dielectric mirror structure, a second dielectric mirror structure, and a light-emitting structure which is arranged vertically between the first dielectric mirror structure and the second dielectric mirror structure, wherein the light-emitting structure is designed to emit light. The first dielectric mirror structure and the second dielectric mirror structure are designed to reflect the light emitted by the light-emitting structure. The light-emitting structure has at least one epitaxially grown layer or is formed thereof. At least one of the first dielectric mirror structure and the second dielectric mirror structure is free of epitaxially grown layers.

Description

[0001] MICRO-THIN-FILM SURFACE EMITTER

[0002] Description

[0003] This description generally relates to a vertical cavity surface emitting laser (VCSEL) and a method for its manufacture.

[0004] For some display sensing applications, precise control of the far-field pattern of the illuminating light source is required. Vertically emitting devices are of particular interest for display sensing because the light source should be small and very thin so that it can be distributed on the rear wall of the display (also called display backplane) together with the red, green and blue micro LEDs (also called R-, G-, B-pLEDs). Typically used micro LEDs, which can be distributed on a display backplane by processes such as stamping (also called p-transfer) or LI FT (laser-induced forward transfer), have a more or less Lambertian emission profile and therefore cannot be used for sensing applications that require only vertical emission, i.e.perpendicular to the surface of the device within a cone of ±x degrees.

[0005] A well-known component for vertical light emission is the vertical cavity surface emitting laser (VCSEL), which is a laser diode in which light is emitted perpendicular to the plane of the semiconductor chip. In a surface emitter, an active region, which is formed by epitaxial growth, is typically arranged vertically between two Bragg mirrors (distributed Bragg reflectors, DBRs). As a rule, a lower of the two DBR mirrors is grown before the epitaxial growth of the active layer, and the upper of the two DBR mirrors is also formed by epitaxial growth or as a dielectric layer stack. However, the known surface emitters consist of a growth substrate and therefore have a thickness of a few 100 μm.Conventional surface emitters are therefore not compatible with pLEDs in terms of thickness and transfer process, since transfer of III / V layers from the growth substrate to another carrier wafer would have to be performed through a wafer bonding step.

[0006] The object of the present invention is to provide a surface emitter and a method for its production which meets the above-mentioned requirements.

[0007] In one aspect, a surface emitter is provided, comprising: a first dielectric mirror structure, a second dielectric mirror structure, and a light-emitting structure arranged vertically between the first mirror structure and the second mirror structure, wherein the light-emitting structure is configured to emit light. The first dielectric mirror structure and the second dielectric mirror structure are configured to reflect the light emitted by the light-emitting structure. The light-emitting structure comprises or is formed from at least one epitaxially grown layer. At least one of the first dielectric mirror structure and the second dielectric mirror structure is free of epitaxially grown layers.

[0008] The surface emitter can thus be provided with a low overall height (very thin, printable) and with a purely vertical emission profile or an essentially purely vertical emission profile.

[0009] Illustratively, in the case of the surface emitter, the light-generating, active layer is formed between the p-contact layer and the n-contact layer, and transparent contact layers are formed on opposite sides of the active layer on the p-contact layer and the n-contact layer. The p-contact layer and / or the n-contact layer can be arranged partially insulated from the light-emitting structure, so that a current constriction (aperture) is formed. Mirror structures, for example dielectric Bragg (DBR) mirrors, can be arranged on opposite sides of the active layer on or above the p-contact layer and the n-contact layer. A metallic layer, for example a solderable metal layer, for example a solder metal structure, can be applied to one of the sides of the surface emitter.A post structure made of an adhesive, which is smaller than the "footprint" of the surface emitter, can be arranged between the surface emitter and a carrier wafer of the surface emitter. This makes it possible to remove the surface emitter from the post structure by means of a transfer stamp for a transfer process.

[0010] The above-mentioned surface emitter can exhibit a purely vertical emission profile and a perfectly circular emission profile. The surface emitter can be handled, transferred, and distributed like any pLED chip.

[0011] An angle of the emission cone (divergence) of the surface emitter can be adjusted by the length of the optical resonator (also called optical cavity), for example by means of the layer thicknesses of the epitaxially grown active layer or the p- / n contact layer or the layer thicknesses of the DBR mirrors.

[0012] Furthermore, the light emitted by the surface emitter can be coherent and monomodal, or the surface emitter can be configured in such a way by means of its structure.

[0013] The emission color of the light emitted by the surface emitter can be adjusted (during manufacturing) within a range extending from ultraviolet (UV) through visible light (RGB) to mid-infrared (MIR). For the purposes of this description, light therefore includes visible light as well as non-visible light in the UV or IR range.

[0014] The surface emitter can be arranged to be electrically contactable vertically , for example with contacts on opposite sides of the active layer , or horizontally , for example with contacts on a common side .

[0015] In a further aspect, a method for manufacturing a surface emitter is provided. The method comprises: forming a light-emitting structure on a growth carrier by means of an epitaxial process; forming a first dielectric mirror structure on the light-emitting structure and applying a carrier wafer to the first mirror structure; removing the growth carrier from the light-emitting structure so that the light-emitting structure is exposed; and forming a second dielectric mirror structure on or above the exposed light-emitting structure.

[0016] The proposed surface emitter is scalable and suitable for mass production. The invention is set forth in the appended claims.

[0017] In the drawings, like reference characters generally refer to the same parts throughout the several views. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the principles of the invention. In the following description, various aspects of the invention are described with reference to the following drawings, in which:

[0018] FIG. 1 shows a schematic cross-sectional view of a surface emitter;

[0019] FIG. 2 shows a flow diagram of a method for producing a surface emitter; and

[0020] FIG. 3 to FIG. 17 show schematic cross-sectional views in

[0021] Manufacturing process of a

[0022] Surface emitter. The following detailed description refers to the accompanying drawings which, for illustrative purposes, show specific details and aspects in which the disclosure may be practiced. One or more aspects are described in sufficient detail to enable those skilled in the art to put the disclosure into practice. Other aspects may be used, and structural, logical, and electrical changes may be made without departing from the scope of the disclosure. The various aspects described herein are not necessarily mutually exclusive, as some aspects may be combined with one or more other aspects to form new aspects. Various aspects are described in connection with methods, and various aspects in connection with devices.It should be understood, however, that aspects described in connection with methods may also apply to devices, and vice versa. In the drawings, it is noted that identical or similar elements, features, and structures are represented by identical reference numerals. In the drawings, it should be noted that proportions need not be to scale and that the size of features may be exaggerated for clarity.

[0023] FIG. 1 shows a schematic cross-sectional view of a surface emitter 100. The surface emitter 100 has a light-emitting structure 102 between a first dielectric mirror structure 104 and a second dielectric mirror structure 106. Light 110 emitted by the light-emitting structure 102 in the direction of the second dielectric mirror structure 106 is reflected by the second dielectric mirror structure 106 in the direction of the first dielectric mirror structure 104. The first dielectric mirror structure 104 can have a (slightly) lower reflectivity than the second dielectric mirror structure 106. As a result, a portion 112 of the light is coupled out or emitted from the first dielectric mirror structure 104. A metallic layer, for example a metal layer 108, may be formed on the second dielectric mirror structure 106 to increase the reflectivity.

[0024] At least one mirror structure of the first dielectric mirror structure 104 and the second dielectric mirror structure 106, for example the first dielectric mirror structure 104 and the second dielectric mirror structure 106, can be free of epitaxially formed layers. For example, at least one mirror structure of the first dielectric mirror structure 104 and the second dielectric mirror structure 106 can be a DBR mirror formed by means of a layer deposition process, which is formed from a plurality of alternating dielectric layers with different refractive indices. Such a mirror allows materials with a high refractive index contrast to be used for the layers of a DBR mirror. As a result, the epitaxially free mirror structure can be provided with a smaller layer thickness than a DBR mirror formed from epitaxially grown layers.As a result, the surface emitter has a smaller thickness and thus better vertical integration.

[0025] Furthermore, the light-emitting structure 102 can be substrate-free. In other words, the light-emitting structure 102 can essentially only have epitaxially formed layers and a growth substrate can have been removed before forming the dielectric mirror structures. A substrate typically has a thickness of several hundred μm. A substrate-free light-emitting structure 102 or a substrate-free surface emitter 100 can thus have a smaller thickness than a conventional surface emitter and can thus have improved vertical integrability. For example, the total thickness of the surface emitter can be less than 10 μm, for example less than 5 μm.

[0026] In other words, the surface emitter 100 may include a first dielectric mirror structure 104, a second dielectric mirror structure 106, and a light-emitting structure 102 arranged vertically between the first dielectric mirror structure 104 and the second dielectric mirror structure 106. The light-emitting structure 102 may be configured to emit light. The first dielectric mirror structure 104 and the second dielectric mirror structure 106 may be configured to reflect the light 110 emitted by the light-emitting structure 102. The light-emitting structure 102 may include or be formed from at least one epitaxially grown layer. At least one of the first dielectric mirror structure 104 and the second dielectric mirror structure 106 may be free of epitaxially grown layers. The surface emitter 100 may be substrate-free.

[0027] The light-emitting structure 102 can be formed as a stack of epitaxially grown layers. The at least one mirror structure of the first dielectric mirror structure 104 and the second dielectric mirror structure 106, which is free of epitaxially grown layers, directly or indirectly adjoins the light-emitting structure 102.

[0028] The at least one mirror structure of the first dielectric

[0029] Mirror structure 104 and the second dielectric

[0030] Mirror structure 106 , which is free of epitaxially grown layers, can have a Bragg mirror .

[0031] The first dielectric mirror structure 104 and the second dielectric mirror structure 106 may each be free of epitaxially grown layers. The first dielectric mirror structure and the second dielectric mirror structure may, for example, each comprise a Bragg mirror.

[0032] The light may be electromagnetic radiation in the non-visible spectral range, for example, in the ultraviolet spectrum, the near-infrared range, or the mid-infrared range. The light-emitting structure 102 may comprise or be formed from essentially exclusively epitaxially grown layers.

[0033] The first dielectric mirror structure 104, the light-emitting structure 102, and the second dielectric mirror structure 106 may form an optical cavity. The optical cavity may be configured such that the surface emitter 100 emits light of a predetermined frequency.

[0034] At least a portion of the light emitted by the surface emitter 100 may be coherent.

[0035] The light emitting structure 102 can be arranged vertically between the first dielectric mirror structure and the second dielectric mirror structure.

[0036] The light-emitting structure 102 may be configured to emit light, and the first dielectric mirror structure 104 and the second dielectric mirror structure 106 may be configured to reflect the light emitted by the light-emitting structure.

[0037] FIG. 2 shows a flow diagram of a method 200 for producing a surface emitter. The method comprises forming 202 a light-emitting structure by means of an epitaxial method on a growth carrier. The method 200 further comprises forming 204 a first dielectric mirror structure on the light-emitting structure and applying a carrier wafer to the first dielectric mirror structure. The method further comprises removing 206 the growth carrier from the light-emitting structure so that the light-emitting structure is exposed, and forming a second dielectric mirror structure on or above the exposed light-emitting structure. The surface emitter can therefore be substrate-free, for example free of the growth carrier. Furthermore, at least one, for example both, mirror structure(s) can therefore be free of epitaxially grown layers.This enables a light-emitting component for sensor applications with an improved beam profile and improved vertical integration into an existing system.

[0038] At least one of the first dielectric mirror structure 104 and the second dielectric mirror structure 106 may be formed free of epitaxially grown layers.

[0039] The growth support may be a substrate, and the surface emitter 100 may become substrate-free by removing the growth support.

[0040] The light-emitting structure can be formed as a stack of epitaxially grown layers. The at least one mirror structure of the first dielectric mirror structure and the second dielectric mirror structure, which is free of epitaxially grown layers, can directly adjoin the light-emitting structure.

[0041] The at least one mirror structure of the first dielectric mirror structure and the second dielectric mirror structure, which is free of epitaxially grown layers, can be formed with a Bragg mirror or as a Bragg mirror.

[0042] The first dielectric mirror structure and the second dielectric mirror structure can each be formed free of epitaxially grown layers.

[0043] The first dielectric mirror structure and the second dielectric mirror structure can each be formed with a Bragg mirror.

[0044] The light can be electromagnetic radiation in the non-visible spectral range, for example in the ultraviolet spectrum, in the near infrared range or in the mid-infrared range.

[0045] The light-emitting structure 102 can be formed essentially exclusively from epitaxially grown layers.

[0046] The first dielectric mirror structure, the light-emitting structure 102, and the second dielectric mirror structure may form an optical cavity. The optical cavity may be configured such that the surface emitter 100 emits light of a predetermined frequency. At least a portion of the light emitted by the surface emitter 100 may be coherent.

[0047] FIG. 3 to FIG. 16 show schematic cross-sectional views in the manufacturing process of a surface emitter 100, as is schematically illustrated in FIG. 1. FIG. 17 illustrates a schematic cross-sectional view of an alternative surface emitter. FIG. 3 to FIG. 17 illustrate the production of two or more surface emitters simultaneously on common (shared) growth carriers. However, it is pointed out that the described manufacturing process can also be applied to a single surface emitter. Furthermore, it is pointed out that the process illustrated below is merely an illustrative example and the layers can also be formed in a different order, for example first the dielectric layer 502 and then the first contact layer 402 and the second contact layer 602 as in a common manufacturing process.It is further pointed out that the individual layers or structures can be formed from one or more sub-layers depending on the application, unless otherwise stated.

[0048] FIG. 3 shows epitaxial layers of the surface emitter, for example epitaxially grown layers, which are arranged on a growth substrate 300. The epitaxial layers have: a buffer layer 302 directly on the growth substrate 300; a stop layer 304 directly on the buffer layer 302; at least one n-contact layer (for example an n-doped semiconductor layer) 306 on the stop layer 304; at least one active layer 308 with a multi-quantum well (MQW) on the n-contact layer 306; at least one p-contact layer 310 (for example a p-doped semiconductor layer) on the active layer 308. The growth substrate 300 can be, for example, a gallium arsenide (GaAs) wafer or another III / V semiconductor substrate. The epitaxial layers, for example n- / p-contact layers, can be application-specific, known epitaxial layers, for example InGaAs or AlGaAs layers.

[0049] The light-emitting structure can, for example, be formed with a stop layer. The growth carrier can be removed down to the stop layer 304. The stop layer can, for example, comprise or be formed from indium gallium aluminum phosphide (InGaAlP). At least one layer to be removed with the growth carrier, which borders the stop layer, for example, the buffer layer 302 and / or a part of the n-contact layer 306, can comprise or be formed from gallium arsenide (GaAs). This enables, for example, a sufficient etch contrast between the stop layer 304 and the buffer layer 302 or the n-contact layer 306 to remove the growth carrier.

[0050] FIG. 4 shows a structured first contact layer 402 directly on the p-contact layer 310 of the layer structure illustrated in FIG. 3. The structured first contact layer 402 can be deposited as a continuous layer, which is subsequently structured. Alternatively, the first contact layer 402 can be deposited in a structured manner. The structured first contact layer 402 can, for example, be formed from a transparent or light-permeable conductive material, for example a transparent conductive oxide (TCO), for example from indium tin oxide (ITO). Alternatively or additionally, the structured first contact layer 402 can be formed as a tunnel electrode or have such a tunnel electrode.

[0051] FIG. 5 shows a dielectric layer 502 as passivation directly on the p-contact layer 310 between regions of the structured first contact layer 402 of the layer structure illustrated in FIG. 4.

[0052] FIG. 6 shows a structured second contact layer 602 directly on the structured first contact layer 402 and a part of the dielectric layer 502 of the layer structure illustrated in FIG. 5. The second contact layer 602 partially overlaps the dielectric layer 502. This brings about better current coupling into the epitaxial layers 306, 308, 310 of the light-emitting structure. In other words, in an overlap region adjacent to the first contact layer 402, the second contact layer 602 overlaps, for example covers, the dielectric layer 502. The second contact layer 602 can increase or thicken a thickness of the first contact layer 402. It should be noted that the structure of the first contact layer 402 and the dielectric layer 502 can form or bring about an electrical and / or optical aperture for beam shaping of the surface emitter.

[0053] FIG. 7 shows a structured layer stack in which the layer stack of FIG. 6 was structured by means of mesa etching. In this case, the layer stack was removed laterally next to the overlap region up to the stop layer 304. This essentially allows the "footprint" of the surface emitter to be defined. The overlap region comprises the region in which the second contact layer is exposed and overlaps the dielectric layer 502, and in which the dielectric layer 502 is exposed.

[0054] FIG. 8 shows a layer stack in which a dielectric first mirror structure 802 was formed on the layer stack of FIG. 7. The first dielectric mirror structure 802 can, for example, be or have a DBR mirror which was formed epitaxially or epitaxially without epitaxy by depositing a layer sequence. The deposition can be carried out by sputtering, evaporation or chemical vapor deposition (CVD). The first dielectric mirror structure 802 can be structured such that one or more contact regions are formed. The second contact layer 602 can be exposed in the contact region. The stop layer 304 can be exposed next to the layer stack or be free of the first mirror structure 802.

[0055] FIG. 9 shows a layer stack in which a metallic layer 902, for example a solderable metal layer (also referred to as a solder metal layer), has been formed on the layer stack of FIG. 8. The metallic layer 902 is formed directly on the first dielectric mirror structure 802 and is formed in the at least one contact region in which the first contact layer 602 is exposed. The stop layer 304 can be exposed next to the layer stack or can be free of solder metal layer 902. It is pointed out that this structure is designed for vertical contacting of the surface emitter. An alternative structure for horizontal contacting of the surface emitter is illustrated in FIG. 17. The metallic layer 902 can be formed from one or more identical or different layers, for example as a layer stack.The metallic layer 902 can be configured for temperature management of the surface emitter, for example, for heat dissipation as a heat sink. Alternatively or additionally, the metallic layer 902 can be configured as an encapsulation structure for the optically and / or electrically active layers, for example, the epitaxial layers, for example, with regard to the diffusion of water or moisture. Alternatively or additionally, the metallic layer 902 can serve as a reflector for the first mirror structure 802 to increase the reflectivity of the first mirror structure 802.

[0056] FIG. 10 shows a layer stack in which a sacrificial layer

[0057] 1002 was formed on the layer stack of FIG. 9, for example by deposition, planarization and subsequent structuring of the sacrificial layer 1002. Alternatively, the sacrificial layer 1002 is deposited without planarization, so that the sacrificial layer 1002 conformally covers the surface of the layer stack. The sacrificial layer 1002 is formed directly on the solder metal layer 902 and on the stop layer 304, in regions in which it is exposed. The sacrificial layer 1002 can have a contact region in the region of the solder metal layer 902 in which it is exposed or is free of sacrificial layer 1002. The sacrificial layer 1002 is designed such that it has a sufficiently high etch contrast to the material of the metallic layer 902 with regard to a predetermined etching process. The sacrificial layer 1002 can, for example, comprise or be formed from SiO2, ZnO or a polymer.

[0058] FIG. 11 shows a layer stack in which a carrier wafer 1102 has been formed on the sacrificial layer 1002 of the layer stack of FIG. 10, for example, by means of a wafer-to-wafer bonding process. The carrier wafer 1102 can be applied by means of an adhesive layer 1106, which is arranged between the carrier wafer 1102 and the sacrificial layer 1002. The adhesive layer 1106 can be formed with a post structure 1104 in the contact region of the sacrificial layer 1002, i.e., in the opening of the sacrificial layer 1002 in which the solder metal layer 902 is exposed. In other words, in the contact area of ​​the sacrificial layer 1002, the adhesive layer 1106 may extend from the solder layer 902 to the carrier wafer 1102. The contact area may have one or more openings. The contact area here is a physical contact area.If the adhesive layer consists of an electrically conductive material, an initial test of the electro-optical emission properties of the components can be carried out. The adhesive layer 1106 can be arranged in the post structure 1104, for example, with a lower adhesion than region 1106 with the carrier wafer 1102. This enables easier detachment of the surface emitter from the carrier wafer 1102 by means of a transfer stamp, as illustrated in FIG. 16 or FIG. 17. The post structure 1104 can serve as a support structure for the surface emitter in the later course of the method and has a smaller cross-sectional area than a surface of the third contact layer, as will be described in more detail below.

[0059] FIG. 12 shows a layer stack of FIG. 11 in which the growth substrate 300 and the buffer layer 302 down to the stop layer 304 have been removed, for example by means of grinding, etching, laser lift off (LLO) or another conventional method. The growth substrate 300 has been clearly removed and the stop layer 304 exposed. A part of the stop layer 304 can be removed by the method for removing the growth substrate 300. The remaining part of the stop layer 304 can be removed by means of an etching process, for example a wet chemical etching process, as illustrated in FIG. 13. As a result, the n-contact layer can be exposed or provided with an atomically smooth surface and thus the length of the optical cavity can be precisely defined.

[0060] FIG. 14 shows a layer stack of FIG. 13, in which a structured third contact layer 1402 is formed directly on the n-contact layer 306. The third contact layer 1402 laterally overlaps the first dielectric mirror structure 802. The third contact layer 1402 may laterally overlap the dielectric layer 502. The structured third contact layer 1402 may be deposited as a continuous layer, which is subsequently structured. Alternatively, the third contact layer 1402 may be deposited in a structured manner. The structured third contact layer 1402 may, for example, be formed from a transparent or light-permeable conductive material, for example a transparent conductive oxide (TCO), for example from indium tin oxide (ITO).Alternatively or additionally, the structured third contact layer 1402 can be formed as a tunnel electrode or have such a tunnel electrode. A dielectric second dielectric mirror structure 1404 can be formed on the structured third contact layer 1402. The second dielectric mirror structure 1404 can, for example, have a DBR mirror or be formed therefrom, for example analogously to the first mirror structure. The second dielectric mirror structure 1404 can be structured such that one or more contact regions are formed. The third contact layer 1402 can be exposed in the contact region. The third contact layer 1402 can be exposed next to the second dielectric mirror structure 1404 or be free of the second mirror structure 1404.Alternatively or additionally, the second mirror structure 1404 can directly adjoin the n-type contact layer 306 at least in places, for example, in the region of the first contact layer 402. The sacrificial layer 1002 can be free of the third contact layer 1402 and the second mirror structure 1404.

[0061] FIG. 15 shows a layer stack of FIG. 14 in which the sacrificial layer 1002 has been removed. The layer stack of the surface emitter shown in FIG. 15 is held on the carrier wafer 1102 by the post structure 1104. The surface emitters can be removed from the carrier wafer 1102 by means of a transfer stamp 1602 in a transfer printing process, as illustrated in FIG. 16.

[0062] FIG. 17 illustrates a surface emitter with lateral contacts instead of the vertical contacts in the surface emitter illustrated in FIG. 16. In the surface emitter of FIG. 17, the contact areas for external contacting are arranged laterally next to one another, for example on the same side of the light-emitting layer, wherein the solder metal layer has a first region 1702 connected to the p-contact layer and a second region 1704 connected to the n-contact layer. The first region is electrically insulated or electrically separated from the second region.

[0063] In other words, the surface emitter may have an electrical contact structure configured to electrically contact the light-emitting structure. The electrical contact structure may have a contact layer with contact surfaces having a first region 1702 and a second region 1704, which are electrically insulated from one another and arranged on a common side of the surface emitter, for example, on the underside or optically inactive side of the surface emitter (also referred to as a flip-chip contact).

[0064] The following are some examples related to what is described here and shown in the figures.

[0065] Example 1 is a surface emitter comprising: a first dielectric mirror structure, a second dielectric mirror structure, and a light-emitting structure arranged vertically between the first dielectric mirror structure and the second dielectric mirror structure, wherein the light-emitting structure is configured to emit light. The first dielectric mirror structure and the second dielectric mirror structure are configured to reflect the light emitted by the light-emitting structure. The light-emitting structure comprises or is formed from at least one epitaxially grown layer. At least one mirror structure of the first dielectric mirror structure and the second dielectric mirror structure is free of epitaxially grown layers.

[0066] In Example 2, the subject matter of Example 1 can optionally comprise that the surface emitter is substrate-free.

[0067] In Example 3, the subject matter of Example 1 or 2 can optionally comprise that the light-emitting structure is formed as a stack of epitaxially grown layers, and wherein the at least one mirror structure of the first dielectric mirror structure and the second dielectric mirror structure that is free of epitaxially grown layers supports the stack. In Example 4, the subject matter of any of Examples 1 to 3 can optionally comprise that the at least one mirror structure of the first dielectric mirror structure and the second dielectric mirror structure that is free of epitaxially grown layers comprises a Bragg mirror.

[0068] In Example 5, the subject matter of Example 4 can optionally comprise that the first dielectric mirror structure and the second dielectric mirror structure are each free of epitaxially grown layers.

[0069] In Example 6, the subject matter of any one of Examples 1 to

[0070] 5 optionally have that the first dielectric mirror structure and the second dielectric mirror structure each have a Bragg mirror.

[0071] In Example 7, the subject matter of any one of Examples 1 to

[0072] 6 optionally have that the light is an electromagnetic radiation in the non-visible spectral range, in particular in the ultraviolet spectrum, in the near infrared range or in the mid-infrared range.

[0073] In Example 8, the subject matter of any one of Examples 1 to

[0074] 7 optionally have that the light-emitting structure essentially exclusively comprises epitaxially grown layers or is formed therefrom.

[0075] In Example 9, the subject matter of any one of Examples 1 to 8 can optionally comprise the first dielectric mirror structure, the light-emitting structure, and the second dielectric mirror structure forming an optical cavity, wherein the optical cavity is configured such that the surface emitter emits light of a predetermined frequency.

[0076] In Example 10, the subject matter of Example 9 can optionally include at least a portion of the light emitted by the surface emitter being coherent. Example 11 is a method of fabricating a surface emitter. The method comprises: forming a light-emitting structure by an epitaxial process on a growth carrier; forming a first dielectric mirror structure on the light-emitting structure and depositing a carrier wafer on the first dielectric mirror structure; removing the growth carrier from the light-emitting structure such that the light-emitting structure is exposed; and forming a second dielectric mirror structure on or above the exposed second dielectric mirror structure.

[0077] In Example 12, the subject matter of Example 11 can optionally include the light emitting structure being arranged vertically between the first dielectric mirror structure and the second dielectric mirror structure.

[0078] In Example 13, the subject matter of Example 11 or 12 can optionally include the light-emitting structure being configured to emit light, and the first dielectric mirror structure and the second dielectric mirror structure being configured to reflect the light emitted by the light-emitting structure.

[0079] In Example 14, the subject matter of any of Examples 11 to 13 can optionally include that at least one of the first dielectric mirror structure and the second dielectric mirror structure is formed free of epitaxially grown layers.

[0080] In Example 15, the subject matter of any of Examples 11 to 14 can optionally comprise that the growth support is a substrate, and the surface emitter becomes substrate-free by removing the growth support.

[0081] In Example 16, the subject matter of any one of Examples 11 to 15 can optionally include that the light-emitting structure is formed as a stack of epitaxially grown layers, and wherein the at least one mirror structure of the first dielectric mirror structure and the second dielectric

[0082] Mirror structure that is free of epitaxially grown layers that supports the stack.

[0083] In Example 17, the subject matter of any one of Examples 11 to 16 can optionally include that the at least one mirror structure of the first dielectric mirror structure and the second dielectric mirror structure that is free of epitaxially grown layers is formed with a Bragg mirror.

[0084] In Example 18, the subject matter of any one of Examples 11 to 17 can optionally include that the first dielectric mirror structure and the second dielectric mirror structure are each formed free of epitaxially grown layers.

[0085] In Example 19, the subject matter of any one of Examples 11 to 18 can optionally include that the first dielectric mirror structure and the second dielectric mirror structure are each formed with a Bragg mirror.

[0086] In Example 20, the subject matter of any one of Examples 11 to 19 can optionally comprise that the light is electromagnetic radiation in the non-visible spectral range, in particular in the ultraviolet spectrum, in the near infrared range, or in the mid-infrared range.

[0087] In Example 21, the subject matter of any one of Examples 11 to 20 can optionally include that the light-emitting structure is formed substantially exclusively from epitaxially grown layers.

[0088] In Example 22, the subject matter of any of Examples 11 to 21 can optionally include the first dielectric mirror structure, the light-emitting structure, and the second dielectric mirror structure forming an optical cavity, wherein the optical cavity is configured such that the surface emitter emits light of a predetermined frequency. In Example 23, the subject matter of Example 22 can optionally include at least a portion of the light emitted by the surface emitter being coherent.

[0089] In Example 23, the subject matter of any one of Examples 11 to 23 can optionally comprise that the light-emitting structure is formed having a stop layer and the growth carrier is removed up to the stop layer.

[0090] The stop layer can be removed in a subsequent process step.

[0091] Example 24 is a method for producing a plurality of surface emitters, the method comprising producing a plurality of surface emitters according to any one of Examples 11 to 23 on a common carrier wafer, wherein the surface emitters are arranged on the carrier wafer such that they can be transferred individually or in groups to a target substrate by means of a transfer process.

[0092] In Example 25, the subject matter of Example 24 can optionally comprise that the transfer process is selected from the group: stamping, bonding or laser-induced forward transfer.

[0093] Example 26 is a method of manufacturing a display device, the method comprising: manufacturing a plurality of surface emitters according to any one of examples 24 or 25, forming a plurality of light-emitting pixels on a common substrate, and disposing at least one of the surface emitters adjacent to the pixels on the substrate by means of a transfer process.

[0094] In Example 27, the subject matter of Example 26 can optionally comprise that the transfer process is selected from the group: stamping, bonding or laser-induced forward transfer.

[0095] The method may further include any feature applicable to the device described above. The word "exemplary" is used herein to mean "as an example, instance, or illustration." Any example or design described herein as "exemplary" is not necessarily to be understood as preferred or advantageous over other examples or designs.

[0096] The words "plurality" and "multiple" in the description or claims expressly refer to a quantity greater than one. The terms "group of," "set of," "collection of," "series of," "sequence of," "grouping of," etc., and the like in the description or claims, refer to a quantity equal to or greater than one, i.e., one or more. Any term expressed in the plural that is not expressly stated as "plurality" or "multiple" also refers to a quantity equal to or greater than one.

[0097] The term "connected" can be understood in the sense of a (e.g., mechanical, optical, and / or electrical) connection and / or interaction, e.g., direct or indirect. For example, several elements can be connected mechanically, so that they are physically held (e.g., a plug connected to a socket), and electrically, so that they have an electrically conductive path (e.g., signal paths exist along a communicative

[0098] Chain) .

[0099] While the above descriptions and the associated figures depict the components of the optical device as separate elements, those skilled in the art will appreciate the various ways to combine or integrate discrete optical functions into a single element. This may include combining two or more components from a single part. Conversely, those skilled in the art will recognize the possibility of separating a single element into two or more separate elements, such as splitting a single component into two or more separate components. It is believed that the methods described herein are exemplary and, therefore, may be implemented in a corresponding device. Likewise, it is believed that implementations of the devices described herein may be implemented as a corresponding method.It is therefore to be understood that a device according to a method described herein may include one or more components configured to perform any aspect of the respective method.

[0100] All acronyms defined in the above description also apply to all claims contained herein.

[0101] Although the disclosure has been particularly shown and described with reference to certain embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the disclosure as defined by the appended claims. The scope of the disclosure is therefore indicated by the appended claims, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced.

[0102] LIST OF REFERENCE SYMBOLS

[0103] 100 surface emitters

[0104] 102 light-emitting structure

[0105] 104, 106 dielectric mirror structures

[0106] 108 metallic layer

[0107] 110, 112 Light

[0108] 200, 202, 204, 206 Procedures and procedural steps

[0109] 300 growth drivers

[0110] 302 Buffer layer

[0111] 304 Stop layer

[0112] 306 n-contact layer

[0113] 308 active area

[0114] 310 p-contact layer

[0115] 402, 602, 1402 contact layer

[0116] 502 dielectric layer

[0117] 802, 1404 dielectric mirror structure

[0118] 902 metallic layer

[0119] 1002 sacrificial layer

[0120] 1102 carrier wafers

[0121] 1104, 1106 adhesive layer

[0122] 1602 transfer stamp

[0123] 1702, 1704 Areas of the contact layer

Claims

PATENT CLAIMS 1 . A surface emitter, comprising: a first dielectric mirror structure, a second dielectric mirror structure, and a light-emitting structure which is arranged in the vertical direction between the first dielectric mirror structure and the second dielectric mirror structure, wherein the light-emitting structure is configured to emit light, and wherein the first dielectric mirror structure and the second dielectric mirror structure are configured to reflect the light emitted by the light-emitting structure; wherein the light-emitting structure has or is formed from at least one epitaxially grown layer; and wherein at least one of the first dielectric mirror structure and the second dielectric mirror structure is free of epitaxially grown layers, and wherein at least the dielectric mirror structure which is free of epitaxially grown layers is substrate-free.

2. Surface emitter according to claim 1, wherein the surface emitter is substrate-free.

3. Surface emitter according to claim 1 or 2, further comprising an electrical contact structure which is configured to electrically contact the light-emitting structure, wherein the electrical contact structure has a contact layer with a first region and a second region which are electrically insulated from one another and are arranged on a common side of the surface emitter. 4 . Surface emitter according to one of claims 1 to 3 , wherein the at least one mirror structure of the first dielectric mirror structure and the second dielectric mirror structure, which is free of epitaxially grown layers, comprises a Bragg mirror.

5. Surface emitter according to one of claims 1 to 4, wherein the first dielectric mirror structure and the second dielectric mirror structure are each free of epitaxially grown layers.

6. Surface emitter according to one of claims 1 to 5, wherein the first dielectric mirror structure and the second dielectric mirror structure each comprise a Bragg mirror.

7. Surface emitter according to one of claims 1 to 6, wherein the light is an electromagnetic radiation in the non-visible spectral range, in particular in the ultraviolet spectrum, in the near infrared range or in the mid-infrared range.

8. Surface emitter according to one of claims 1 to 7, wherein the light-emitting structure comprises or is formed from essentially exclusively epitaxially grown layers.

9. Surface emitter according to one of claims 1 to 8, wherein the first dielectric mirror structure, the light-emitting structure and the second dielectric mirror structure form an optical cavity, wherein the optical cavity is arranged such that the Surface emitter emits light of a given frequency.

10. Surface emitter according to one of claims 1 to 9, wherein at least a portion of the light emitted by the surface emitter is coherent.

11. A method for producing a surface emitter, the method comprising: forming a light-emitting structure by means of an epitaxial process on a growth carrier; forming a first dielectric mirror structure on the light-emitting structure and applying a carrier wafer on the first dielectric mirror structure; removing the growth carrier from the light-emitting structure so that the light-emitting structure is exposed, and forming a second dielectric mirror structure on or above the exposed light-emitting structure; wherein at least one of the first dielectric mirror structure and the second dielectric mirror structure is formed free of epitaxially grown layers.

12. Method according to claim 11, wherein the light-emitting structure is formed having a stop layer and wherein the growth carrier is removed up to the stop layer, wherein the stop layer comprises or is formed from an indium gallium aluminum phosphide, InGaAlP, and at least one layer to be removed with the growth carrier, which layer adjoins the stop layer, comprises or is formed from a gallium arsenide, GaAs.

13. The method according to claim 11 or 12, wherein the light-emitting structure is arranged in the vertical direction between the first dielectric mirror structure and the second dielectric mirror structure.

14. Method according to one of claims 11 to 13, wherein the light-emitting structure is arranged to emit light, and the first dielectric mirror structure and the second dielectric mirror structure are arranged to reflect the light emitted by the light-emitting structure.

15. The method according to any one of claims 11 to 14, wherein the growth carrier is a substrate, and the surface emitter becomes substrate-free by removing the growth carrier.

16. A method for producing a plurality of surface emitters, the method comprising producing a plurality of surface emitters according to one of claims 11 to 15 on a common carrier wafer, wherein the surface emitters are arranged on the carrier wafer in such a way that they can be transferred individually or in groups to a target substrate by means of a transfer process.

17. The method according to claim 16, wherein the transfer process is selected from the group: stamping, bonding or laser-induced forward transfer.

18. A method for manufacturing a display device, the method comprising Producing a plurality of surface emitters according to one of claims 16 or 17, forming a plurality of light-emitting pixels on a common substrate, and arranging at least one of the surface emitters adjacent to the pixels on the substrate by means of a transfer process.

19. The method according to claim 18, wherein the transfer process is selected from the group: stamping, bonding or Laser-Induced Forward Transfer".

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