Display device

Abstract

Display device (1) with - at least a semiconductor body having a sequence of semiconductor layers (2) having an active region (20) intended for generating radiation and forming a plurality of pixels (2a, 2b), and - a control circuit (54), wherein - the control circuit (54) has a plurality of switches (55), each of which is provided for controlling at least one pixel (2a, 2b); - a first metallization layer (31) and a second metallization layer (32) electrically isolated from the first metallization layer are arranged between the control circuit (54) and the semiconductor body; - the first metallization layer (31) and / or the second metallization layer (32) is electrically connected to at least one of the pixels (2a, 2b); and - the first metallization layer (31) and the second metallization layer (32) are arranged to overlap each other in such a way that the control circuit (54) in view of the display device is covered with at least one of the metallization layers (31, 32) at every point which overlaps with one of the pixels (2a, 2b) or is arranged between two adjacent pixels (2a, 2b).

Description

[0001] A display device is specified.

[0002] For LED-based display devices, individual LEDs can be mounted on a carrier in which a control circuit is integrated. However, radiation emitted by the LEDs and absorbed by the carrier can lead to malfunctions and degradation.

[0003] DE 10 2012 112 302 A1 describes a display device with a layer stack and a control circuit.

[0004] DE 10 2011 056 888 A1 describes a display device with a semiconductor layer sequence and a carrier with a plurality of switches.

[0005] US 2012 / 0 032 218 A1 describes a semiconductor light-emitting diode with two electrode layers.

[0006] WO 2011 / 014 490 A2 describes a pixelated light-emitting diode in which the individual pixels each have the shape of a truncated pyramid.

[0007] One task to be solved is to provide a display device that is characterized by high reliability and age stability.

[0008] This problem is solved, among other things, by the subject matter of the independent patent claim. Embodiments and advantages are the subject matter of the dependent patent claims.

[0009] According to at least one embodiment of the display device, the display device has at least one semiconductor body. The semiconductor body has a semiconductor layer sequence that has an active region provided for generating radiation and forms a plurality of pixels. A peak wavelength of the radiation generated in the active region lies, for example, in the ultraviolet, visible, or infrared spectral range. The active region is arranged, for example, between a first semiconductor layer and a second semiconductor layer, wherein the first semiconductor layer and the second semiconductor layer expediently have different conduction types. During the production of the display device, the pixels of a semiconductor body can arise from a common semiconductor layer sequence.This means that the semiconductor layers, in particular the active areas of the individual pixels of the semiconductor body, are identical in terms of their material composition and layer thicknesses, apart from manufacturing-related variations that occur in the lateral direction across a semiconductor wafer.

[0010] A lateral direction is understood to be a direction that runs parallel to a main extension plane of the semiconductor layers of the semiconductor layer sequence.

[0011] According to at least one embodiment of the display device, the display device comprises a control circuit. The control circuit comprises a plurality of switches, each of which is provided for controlling at least one pixel.

[0012] Preferably, each pixel is assigned at least one switch, in particular exactly one switch. During operation of the display device, each pixel can be controlled by the assigned switch. Thus, several pixels can be controlled simultaneously, in particular all pixels can be controlled simultaneously to emit radiation. For example, an active matrix control circuit for the pixels is formed by the switches.

[0013] According to at least one embodiment of the display device, the display device comprises a carrier. The at least one semiconductor body is arranged on the carrier. The carrier contains, for example, a semiconductor material, such as silicon or germanium, or a ceramic, such as aluminum nitride, aluminum oxide, or boron nitride.

[0014] According to at least one embodiment of the display device, the control circuit is integrated into the carrier. In this case, a semiconductor material, such as silicon, is particularly suitable for the carrier. "Integrated into the carrier" in this context means that at least a portion of the control circuit is formed by the carrier, for example, a semiconductor region of a switch.

[0015] According to at least one embodiment of the display device, the control circuit is arranged between the at least one semiconductor body and the carrier. In this case, the carrier serves in particular to mechanically stabilize the semiconductor layer sequence and can therefore be selected independently of its electrical properties. For example, the control circuit is formed by layers deposited on the semiconductor body. For example, the control circuit can comprise a polycrystalline semiconductor material, in particular polycrystalline silicon. For a mechanical connection between the at least one semiconductor body and the carrier, a connecting layer can be arranged at least regionally between the control circuit and the carrier.

[0016] According to at least one embodiment of the display device, the display device has a first metallization layer between the drive circuit and the semiconductor body. The first metallization layer can be electrically conductively connected to the pixels, in particular to the first semiconductor layer of each pixel. In other words, the first metallization layer fulfills the function of a connection layer for the first semiconductor layer. Alternatively, the first metallization layer can be electrically insulated from the pixels. In this case, the first metallization layer therefore fulfills no electrical function. The first metallization layer is arranged, in particular, between the carrier and the semiconductor body.

[0017] According to at least one embodiment of the display device, the display device has a second metallization layer between the drive circuit and the semiconductor body. The second metallization layer borders, for example, the semiconductor body, in particular the second semiconductor layer. The second metallization layer is, in particular, electrically insulated from the first metallization layer. The first metallization layer is arranged, for example, in the vertical direction, i.e., in a direction perpendicular to the main extension plane of the semiconductor layers of the semiconductor layer sequence, at least in regions between the drive circuit and the second metallization layer. The second metallization layer is, in particular, arranged between the carrier and the semiconductor body.

[0018] The first metallization layer and / or the second metallization layer can be designed to reflect the radiation generated in the active region during operation. The reflectivity is preferably at least 50%, particularly preferably at least 70%, for the radiation generated in the active region. The first metallization layer and / or the second metallization layer thus fulfill the function of a mirror layer that deflects radiation emitted in the direction of the control circuit. The first metallization layer and / or the second metallization layer can also be designed as a single-layer or multi-layer structure.

[0019] According to at least one embodiment of the display device, the first metallization layer and / or the second metallization layer are electrically conductively connected to at least one of the pixels.

[0020] According to at least one embodiment of the display device, the first metallization layer and the second metallization layer are arranged to overlap one another such that the drive circuit, when viewed from above onto the display device, is covered with at least one of the metallization layers at every location that overlaps one of the pixels or is arranged between two adjacent pixels. In particular, there is no direct optical path between the active region and the drive circuit. This means that radiation emitted by the active region cannot penetrate directly, i.e. not without prior reflection at the first metallization layer and / or at the second metallization layer, into the drive circuit and possibly into the carrier. However, in an edge region of the carrier, for example laterally outside the at least one semiconductor body, the carrier can be exposed in places.

[0021] In at least one embodiment of the display device, the display device comprises at least one semiconductor body having a semiconductor layer sequence which has an active region provided for generating radiation and forms a plurality of pixels. The display device further comprises a control circuit, wherein the control circuit has a plurality of switches, each of which is provided for controlling at least one pixel. A first metallization layer and a second metallization layer electrically insulated from the first metallization layer are arranged between the control circuit and the semiconductor body. The first metallization layer and / or the second metallization layer are electrically conductively connected to at least one of the pixels.The first metallization layer and the second metallization layer are arranged overlapping one another such that the drive circuit, in a plan view of the display device, is covered with at least one of the metallization layers at each location that overlaps with one of the pixels or is arranged between two adjacent pixels.

[0022] By means of the overlapping metallization layers, it is possible to prevent radiation generated in the active region and radiated towards the control circuit from being absorbed in the latter and causing malfunctions or degradation phenomena.

[0023] According to at least one embodiment of the display device, the first metallization layer and the second metallization layer are electrically conductively connected to at least one of the pixels.

[0024] According to at least one embodiment of the display device, the first metallization layer or the second metallization layer forms a common contact for a plurality of pixels, in particular for all pixels of the display device. For example, the first metallization layer forms a common electrical contact for a plurality of pixels, and the second semiconductor layer of the pixels is electrically conductively connected to one of the switches by means of the second metallization layer, or vice versa.

[0025] According to at least one embodiment of the display device, the second metallization layer adjoins the semiconductor layer sequence and is severed between two adjacent pixels. The second metallization layer thus defines the region in which charge carriers are injected into the active region via the second semiconductor layer during operation. In other words, the second metallization layer is divided into several spaced-apart regions, with each pixel being assigned exactly one sub-region.

[0026] According to at least one embodiment of the display device, the second metallization layer, when viewed from above, is completely covered by the at least one semiconductor body. In other words, the individual regions of the second metallization layer do not protrude beyond the respective associated semiconductor body at any point in the lateral direction.

[0027] According to at least one embodiment of the display device, the first metallization layer has a recess for each pixel. In particular, the second metallization layer in the recess is electrically conductively connected to the associated switch of the control circuit. In a top view of the display device, the recess completely overlaps with the respectively associated pixel and in particular also with the second metallization layer. The recess therefore does not extend beyond the pixel in the lateral direction. In other words, the first metallization layer is only recessed at locations that are covered with the second metallization layer. In particular, in a top view of the display device, the first metallization layer completely covers the spaces between the pixels.

[0028] According to at least one embodiment of the display device, the recess has an annular border. For example, the border has a circular or elliptical basic shape.

[0029] According to at least one embodiment of the display device, a plurality of semiconductor bodies, each having a plurality of pixels, is arranged on the carrier. During the manufacture of the display device, the individual semiconductor bodies can be positioned sequentially or simultaneously on the carrier. A distance between adjacent semiconductor bodies can be greater than a distance between adjacent pixels of a semiconductor body.

[0030] According to at least one embodiment of the display device, the first metallization layer and the second metallization layer are arranged overlapping one another such that, when viewed from above, the carrier is covered with at least one of the metallization layers at every location that overlaps one of the semiconductor bodies or is arranged between two adjacent semiconductor bodies. Thus, in the region between adjacent semiconductor bodies, there is no direct optical path from the active regions of the semiconductor bodies to the carrier.

[0031] According to at least one embodiment of the display device, the active region is arranged between a first semiconductor layer and a second semiconductor layer, wherein the semiconductor layer sequence has at least one recess which extends from a rear side of the semiconductor layer sequence facing the control circuit through the active region into the first semiconductor layer and is provided for electrically contacting the first semiconductor layer. In particular, the first metallization layer is electrically conductively connected to the first semiconductor layer in the recess. By means of the first metallization layer, the first semiconductor layer can be electrically contacted from the side of the semiconductor layer sequence facing the control circuit.Particularly in a configuration in which the first semiconductor layer extends continuously over all pixels, a single recess may be sufficient for the entire semiconductor body. However, multiple recesses may also be provided. For example, the number of recesses in a semiconductor body is at least as large as the number of pixels in the semiconductor body. This can be applied both to a configuration in which the first semiconductor layer is connected to a switch via the first metallization layer and to a configuration in which the first metallization layer extends continuously over the pixels. Particularly with a comparatively large lateral extent of the individual pixels, two or more recesses per pixel may also be expedient. This simplifies the lateral homogeneous imprinting of charge carriers into the active region of the pixel.

[0032] According to at least one embodiment of the display device, the pixels are electrically contacted from a radiation exit surface of the semiconductor body facing away from the control circuit. In particular, the first semiconductor layer of the pixels is electrically contacted from the radiation exit surface. For example, a connection layer is arranged on the semiconductor body. The connection layer can form a common contact for several or all of the first semiconductor layers of the semiconductor body. Recesses through the active region for contacting the first semiconductor layer can be omitted in this embodiment. The connection layer is expediently transparent or at least translucent for the radiation generated in the active region. For example, the connection layer contains a TCO (transparent conductive oxide) material, such as indium tin oxide (ITO) or zinc oxide.

[0033] According to at least one embodiment of the display device, a growth substrate for the semiconductor layer sequence is removed. In particular, the growth substrate for the semiconductor layer sequence is completely or at least partially removed, or completely or at least partially thinned. The carrier mechanically stabilizes the semiconductor layer sequence, so that the growth substrate is no longer required for this purpose. Preferably, the display device is completely free of the growth substrate. The risk of optical crosstalk between adjacent pixels during operation of the display device can thus be reduced. However, it may also be sufficient to thin the growth substrate only to a predetermined residual thickness.

[0034] According to at least one embodiment of the display device, the active region extends continuously across multiple pixels, in particular across all pixels of the semiconductor body. The active region is thus formed as a continuous whole and is, if necessary, only interrupted by the at least one recess. An additional manufacturing step for severing the active region for the individual pixels is therefore not required.

[0035] According to at least one embodiment of the display device, the active region is divided into a plurality of segments, each forming a pixel, wherein the segments emerge from the common semiconductor layer sequence. The division between adjacent pixels can be formed, for example, by means of a trench that separates at least the active region. In particular, the trench can separate the entire semiconductor layer sequence. By dividing the segments, a separation of charge carrier injection between adjacent pixels can be achieved in a simplified manner. Furthermore, optical crosstalk can be further reduced.

[0036] Alternatively, the trench can be formed only in the first semiconductor layer. This means that the trench does not cut through the active region. Such a trench can improve the optical separation between the pixels without cutting through the active region.

[0037] According to at least one embodiment of the display device, a radiation conversion element is arranged on a side of the semiconductor layer sequence facing away from the control circuit.

[0038] The radiation conversion element is in particular intended to convert at least part of the radiation generated in the active region with a first peak wavelength into secondary radiation with a second peak wavelength different from the first peak wavelength.

[0039] According to at least one embodiment of the display device, the radiation conversion element extends continuously over several pixels.

[0040] According to at least one embodiment of the display device, the radiation conversion element has a plurality of segments, each of which is assigned at least one pixel. For example, three or more pixels can be combined to form a color triplet, which is intended for generating radiation in the red, green, and blue spectral ranges. Such a display device is suitable for the full-color display of still or moving images.

[0041] The display device can be manufactured in a wafer assembly, with multiple display devices resulting from the wafer assembly being singulated, for example, by sawing or using a laser separation process. The singulation into the display devices takes place, in particular, only after the semiconductor bodies have been attached to the carrier.

[0042] Further features, embodiments and expediencies emerge from the following description of the embodiments in conjunction with the figures.

[0043] They show: the Fig. 1A and Fig. 1B shows a first embodiment of a display device in a schematic sectional view ( Fig. 1A) and associated supervision ( Fig. 1B); the Fig. 2 and Fig. 3 a second or third embodiment of a display device in a schematic sectional view; and the Fig. 4 a fourth embodiment of a display device in schematic plan view.

[0044] Identical, similar or similarly acting elements are provided with the same reference symbols in the figures.

[0045] The figures and the proportions of the elements depicted in the figures are not to be considered to scale. Rather, individual elements, and in particular layer thicknesses, may be exaggerated for clarity and / or clarity.

[0046] In Fig. Figure 1A shows a first exemplary embodiment of a display device 1 schematically in a sectional view. The display device has a plurality of pixels arranged next to one another, in particular in a matrix-like manner. For simplified illustration, the figure shows a section of the display device with a first pixel 2a and a second pixel 2b.

[0047] The display device 1 has a semiconductor body with a semiconductor layer sequence 2. The semiconductor body extends in a vertical direction between a radiation exit surface 29 and a rear side 27 opposite the radiation exit surface. The semiconductor layer sequence has an active region 20 provided for generating radiation. The active region is arranged between a first semiconductor layer 21 of a first conductivity type and a second semiconductor layer 22 of a second conductivity type different from the first conductivity type. For example, the first semiconductor layer can be n-conductive and the second semiconductor layer p-conductive, or vice versa. A plurality of recesses 25 are formed in the semiconductor layer sequence 2, which extend from the rear side 27 through the second semiconductor layer 22 and the active region 20 into the first semiconductor layer 21.In particular, the recesses end in the first semiconductor layer.

[0048] The active region 20 can be designed to generate radiation in the visible spectral range, the ultraviolet spectral range, or the infrared spectral range. In particular, the active region can have a quantum well structure, for example, a multiple quantum well structure.

[0049] The semiconductor layer sequence 2, in particular the active region 20, preferably comprises a III-V compound semiconductor material. The semiconductor material can in particular contain at least one group III element from the group consisting of Ga, Al, and In and at least one group V element from the group consisting of N, P, and As.

[0050] III-V compound semiconductor materials are used to generate radiation in the ultraviolet (Al x In y Ga 1-x-y N) over the visible (Al x In y Ga 1-x-yN, especially for blue to green radiation, or Al x In y Ga 1-x-y P, especially for yellow to red radiation) to the infrared (Al x In y Ga 1-x-y As) spectral range is particularly suitable. Here, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, and x + y ≤ 1 apply, in particular with x ≠ 1, y ≠ 1, x ≠ 0, and / or y ≠ 0. With III-V compound semiconductor materials, especially from the aforementioned material systems, high internal quantum efficiencies can still be achieved in radiation generation.

[0051] The display device 1 further comprises a carrier 5 on which the semiconductor layer sequence 2 is arranged and fastened. Integrated into the carrier 5 is a control circuit 54 having a plurality of switches 55, which may be formed, for example, as a single transistor or as a circuit with multiple transistors and one or more capacitors. A first connection surface 51 is formed on a main surface 50 of the carrier 5 facing the semiconductor layer sequence 2. The first connection surface is provided for an electrically conductive connection to the first semiconductor layer 21 of the pixels 2a, 2b. The first connection surface is formed as a continuous surface. Furthermore, a plurality of second connection surfaces 52 are formed on the main surface of the carrier.The second connecting surfaces are each provided for an electrically conductive connection between the switches 55 and the associated pixels of the semiconductor bodies 2.

[0052] In a top view of the display device 1, an insulating region 53 is formed between adjacent second connecting surfaces 52. The insulating region insulates the carrier 5 from the first metallization layer 51. Furthermore, supply lines 57 are formed in the carrier 5, via which the pixels of the display device can be controlled via an electrical control circuit.

[0053] The carrier 5 can be formed, for example, as a silicon carrier, in which the switches 55 can be implemented using CMOS (Complementary Metal Oxide Semiconductor) technology. In addition to the switches 55, the carrier can also include other electronic components for controlling the display device 1, for example, a shift register or a programmable logic module.

[0054] In addition to the electrical control of the pixels 2a, 2b, the carrier 5 serves to mechanically stabilize the semiconductor layer sequence 2. A growth substrate for the preferably epitaxial deposition of the semiconductor layer sequence is no longer required for this purpose and can therefore be removed during the manufacture of the display device.

[0055] The semiconductor body with the semiconductor layer sequence 2 is mechanically and in particular also thermally conductively connected to the carrier 5 via a connecting layer 7, so that the waste heat generated during operation can be efficiently dissipated via the carrier. Suitable methods for producing the connecting layer include, for example, soldering, such as solder paste, silver sintering, a direct bonding process, or contacting via contact bumps, wherein an underfill material can be formed between the individual contact bumps to increase mechanical stability. A metal, such as gold, silver, copper, nickel, tin, or a metallic alloy comprising at least one of the aforementioned materials, such as gold-tin, copper-silver-tin, indium-tin, or nickel-tin, is particularly suitable for the connecting layer 7.

[0056] For the electrical connection of the pixels 2a, 2b of the semiconductor layer sequence 2 to the carrier 5, a first metallization layer 31 and a second metallization layer 32 are arranged between the semiconductor layer sequence 2 and the carrier 5. The first metallization layer 31 extends through the recesses 25 and electrically contacts the first semiconductor layer 21. Accordingly, the second metallization layer 32 electrically contacts the second semiconductor layer 22 and directly borders the second semiconductor layer. The metallization layers are preferably designed to be reflective for the radiation generated in the active region 20. For example, silver is characterized by particularly high reflectivity in the visible and ultraviolet spectral ranges.Alternatively, another metal, for example, aluminum, nickel, gold, rhodium, or palladium, or a metallic alloy containing at least one of the aforementioned materials, for example, a silver-palladium alloy or Au:Ge, can also be used. The metallization layers 31, 32 can also be formed in multiple layers.

[0057] In a top view of the display device 1, the first metallization layer 31 and the second metallization layer 32 are arranged overlapping one another such that the main surface 50 of the carrier 5 with the drive circuit 54 is covered with at least one of the metallization layers in the lateral direction at every location that overlaps one of the pixels 2a, 2b or is arranged between two adjacent pixels. Interruptions in the first metallization layer and the second metallization layer, for example, for electrical contact routing or pixel definition, are thus arranged offset from one another.With such an arrangement, it can be achieved that the carrier with the control circuit is protected from radiation emitted from the active region 20 in the direction of the carrier 5 during operation of the display device 1, even when the individual pixels can be individually controlled, in particular by means of an active matrix control circuit. This radiation is prevented from entering the carrier 5 in the lateral direction by at least one of the metallization layers, i.e. at every point, and can also be at least partially redirected towards the radiation exit surface. This prevents the carrier 5 from being exposed to the generated radiation, in particular below the active regions and in the lateral direction between the active regions. The risk of radiation-induced malfunction or degradation of the control circuit 54 is thereby minimized.

[0058] The first metallization layer 31 has a plurality of cutouts 310. Vias 320 are formed in the cutouts, via which the second metallization layer 32 of the respective pixels is electrically conductively connected to the associated second connecting surfaces 52. In a plan view of the display device, the vias 310 are completely covered by the second metallization layer 32. The cutouts 310 are preferably annular. It has been shown that this minimizes the area on which the semiconductor body 2 is not mechanically supported by the connecting layer 7. The risk of crack formation is thus reduced, for example, compared to linear cutouts. Of course, another basic geometric shape is also conceivable for the cutout, for example a polygonal, for example a rectangular, in particular square, or hexagonal basic shape.

[0059] In the embodiment shown, the second metallization layer 32 forms an electrically conductive connection for each pixel 2a, 2b with the second connection surface 52 of the associated switch 55. The first semiconductor layer 21 is continuously electrically contacted by means of the first metallization layer 31, so that the first metallization layer forms a common contact for all pixels 2a, 2b of the display device and is directly connected to a supply line 57.

[0060] The common contact can be connected to a supply line 57 at one or more points or can be led directly out of the display device 1.

[0061] A first insulation layer 41, for example a silicon oxide layer, is arranged between the first metallization layer 31 and the second metallization layer 32. The insulation layer serves for the electrical insulation between the first metallization layer 31 and the second metallization layer 32 as well as for the electrical insulation of the first metallization layer from the second semiconductor layer 22 and the active region 20 in the region of the recesses 25. The side surfaces of the semiconductor layer sequence 2, in particular the active region 20, are covered with a second insulation layer 42. The side surfaces can be as in Fig. 1A. In this case, the lateral extension of the semiconductor layer sequence increases toward the carrier. Alternatively, negative flank angles can also be provided.

[0062] During operation of the display device 1, the pixels 2a, 2b can be operated independently of one another and, in particular, simultaneously via the switches 55. In contrast to an embodiment in which the pixels are connected row by row and column by contact lines, the number of pixels can thus be increased without having to reduce the switching times per pixel at a predetermined repetition frequency. Therefore, to achieve the same brightness of the pixels, the current through the pixels does not have to be increased. Despite the individual controllability of the pixels, the overlapping metallization layers as described ensure that the radiation generated during operation cannot penetrate into the carrier 5 and cause damage to or malfunction of the control circuit 54.

[0063] In the exemplary embodiment shown, the semiconductor layer sequence 2 extends continuously over the pixels 2a, 2b. The active region 20 is thus formed as a continuous region. The lateral extent of a pixel in this exemplary embodiment results essentially from the lateral extent of the second metallization layer 32. The regions of the second metallization layer separated from one another by the interruptions between the pixels thus determine the shape of the pixels. The pixels can be Fig. 1B, they have a square basic shape. However, a different basic shape, in particular one that is at least partially curved or polygonal, such as a triangular, rectangular, or hexagonal basic shape, may also be used.

[0064] In the area of ​​the interruptions between the regions of the second metallization layer 32 of the pixels 2a, 2b, the first metallization layer 31 runs continuously when viewed from above the display device 1, so that the main surface 50 of the carrier 5 is not visible at any point between the pixels. The radiation generated during operation is thus efficiently prevented from entering the carrier 5 with the drive circuit 54.

[0065] The design of the first connecting surface 51 and the second connecting surfaces 52 is mirror-imaged to the design of the first metallization layer 31 and the vias 320, so that the first connecting surface 51 with the first metallization layer and the second connecting surfaces with the vias can be easily connected to one another via the connecting layer 7 during manufacture.

[0066] The number of recesses 25 can be varied within wide limits depending on the size of the pixels and the transverse conductivity of the first semiconductor layer. Thus, in contrast to the illustrated embodiment, not every pixel needs to have its own recess 25 or even several separate recesses 25. Rather, several adjacent pixels can also have a common recess 25. In extreme cases, a single recess may be sufficient for the entire display device.

[0067] The edge length of the individual pixels 2a, 2b can be varied within a wide range. For example, the edge length can be between 1 µm and 1 mm inclusive. For the formation of a pixelated headlight, for example, for an adaptive front lighting system (AFS) in a motor vehicle, the edge length is preferably between 20 µm and 150 µm inclusive. For a projection display, the edge length is preferably between 1 µm and 5 µm inclusive.

[0068] The non-emissive distances between adjacent pixels can be between 0.5 µm and 20 µm inclusive.

[0069] A radiation conversion element 6 is formed on the radiation exit surface 29 of the semiconductor layer sequence. In the exemplary embodiment shown, the radiation conversion element is formed as a continuous element having a plurality of segments 6a, 6b. Each pixel is assigned exactly one segment. A separating web 61 is formed between adjacent segments. The separating webs can be used to optically isolate the segments 6a, 6b from one another. The optical separation between the pixels 2a, 2b is thus increased. Depending in particular on the thickness of the conversion element and / or the concentration of scattering centers in the conversion element, the separating webs can also be omitted.

[0070] For a display device 1 intended for displaying full-color still or moving images, the segments 6a, 6b can be provided for generating radiation with a secondary wavelength and different peak wavelengths. For example, a color triplet for generating radiation in the red, green, and blue spectral ranges can be formed using three segments 6a, 6b. Of course, it is also conceivable to design the radiation conversion element 6 as a discontinuous unit and to apply the radiation conversion element to the respective pixels 2a, 2b in the form of mechanically separated individual segments.

[0071] The radiation conversion element 6 can be attached in prefabricated form to the radiation exit surface 29 or formed directly on the radiation exit surface. Furthermore, the radiation conversion element can be formed, for example, using ceramic particles, quantum dots, or organic molecules. These can be embedded in a matrix material, for example, a polymer matrix material, such as a silicone or an epoxy, or a hybrid material comprising a silicone and an epoxy. Alternatively, the radiation conversion element can also be formed as a ceramic radiation conversion element, in which the particles intended for radiation conversion form a ceramic by themselves, for example, by sintering, or are combined with other materials to form a ceramic.

[0072] For a pixelated headlight, the segments 6a, 6b of the radiation conversion element 6 can also be designed similarly. For example, the segments can be provided for the radiation conversion of blue radiation generated in the active region 20 into secondary radiation in the yellow spectral range, so that light that appears white to the human eye is emitted.

[0073] Alternatively, the radiation conversion element 6 can be designed as a continuous element that extends across the pixels 2a, 2b. The radiation conversion element can, in particular, be formed in one piece.

[0074] Deviating from the described embodiment, the second metallization layer 32 can also be designed as a common contact for the pixels 2a, 2b. In this case, the pixels are each electrically connected to the associated switch via the first metallization layer 31.

[0075] In the described embodiment, the first metallization layer and the second metallization layer therefore serve both to electrically contact the pixels and to continuously protect the carrier 5 with the control circuit 54 from radiation emitted by the active regions 20 and the radiation conversion elements 6.

[0076] Deviating from the described exemplary embodiment, the control circuit 54 can also be formed separately from the carrier 5. For example, the control circuit can be formed by means of one or more layers arranged between the at least one semiconductor body with the semiconductor layer sequence 2 and the carrier. The layers can be deposited, for example, by means of a deposition method, for example by means of PECVD, on the semiconductor body with the semiconductor layer sequence 2 before the semiconductor body with the semiconductor layer sequence is attached to the carrier 5. For example, the control circuit 54 can comprise a polycrystalline semiconductor material, for example polycrystalline silicon. To produce the semiconductor material, amorphous material can be deposited and subsequently recrystallized.Compared to amorphous semiconductor material, polycrystalline or monocrystalline semiconductor material can exhibit greatly increased charge carrier mobility. For example, by recrystallizing amorphous silicon, a charge carrier mobility can be achieved that is half that of monocrystalline material or more. By using polycrystalline semiconductor material instead of amorphous semiconductor material, switches can be formed in the control circuit in a simplified manner, which are also capable of switching the currents required for generating radiation in the pixels of the display device. Recrystallization can be carried out, for example, using a laser beam that is scanned over the surface of the amorphous layer. Recrystallization can occur over the entire surface or only in certain regions. Recrystallization can also be carried out in a multi-stage process.There is no need for aligned bonding to attach a carrier with a control circuit integrated into the carrier.

[0077] In this case, an electrically insulating material, such as a ceramic, can also be used for the carrier as an alternative to a semiconductor material. The connecting layer 7 is arranged between the control circuit 54 and the carrier 5 in this case and can also be electrically insulating. The metallization layers 31, 32 are arranged between the semiconductor body 2 and the control circuit, thus protecting the control circuit from the radiation generated in the semiconductor body and radiated toward the control circuit.

[0078] The Fig. The second embodiment shown schematically in Figure 2 essentially corresponds to the one described in connection with the Fig. 1A and Fig. 1B. In contrast, adjacent pixels 2a, 2b are separated from one another by means of a trench 26. The trench extends from the radiation exit surface 29 at least through the active region, preferably through the entire semiconductor layer sequence 2. Segments 20a, 20b of the active region 20b arranged between the trenches 26 each form the pixels 2a, 2b. The pixels 2a, 2b can be optically and electrically separated from one another in a simplified manner by means of the trenches. For a purely optical separation of the pixels, the trenches can also extend only from the radiation exit surface 29 into the first semiconductor layer 21, without severing the active region 20. Such trenches can also be used with a continuous first semiconductor layer 21, as for example in connection with the Fig. 1A and Fig. 1B apply.

[0079] The side surfaces of the trenches 26 are covered with the second insulation layer 42. The trenches can be unfilled or filled with a filler material. The filler material can be transparent, absorbent, or reflective to the radiation generated in the active region 20. Using an absorbent or reflective filler material, the optical separation between adjacent pixels can be increased. A dielectric material, such as a polymer material, is suitable as a transparent or absorbent filler material for the trenches. A metal layer or a plastic filled with reflective particles, such as titanium oxide, can be used as the reflective material. If a dielectric material is used as the filler material, the second insulation layer 42 on the side surfaces of the trenches 26 can also be omitted.

[0080] Furthermore, a pixel 2a, in contrast to the pixel shown in the Fig. 1A and Fig. 1B, the first semiconductor layer 21 has a plurality of recesses 25 for contacting the first semiconductor layer 21. Multiple recesses per pixel are particularly suitable for display devices with comparatively large pixels 2a, 2b, for example, in a display device for a pixelated headlight.

[0081] The Fig. The third embodiment shown in Figure 3 essentially corresponds to the one described in connection with the Fig. 1A and Fig. 1B. In contrast, the electrical contacting of the first semiconductor layer 21 takes place via a connection layer 33 arranged on the radiation exit surface 29. The connection layer is permeable to the radiation generated during operation. For example, the connection layer contains a TCO material, such as ITO or zinc oxide. The connection layer 33 is connected to a lead 57 of the carrier and forms a common contact for the first semiconductor layer. The first metallization layer 31, on the other hand, does not serve to electrically contact the pixels, but is additionally provided to continuously shield the carrier 5 with the control circuit 54 together with the second metallization layer 32 from the radiation emitted during operation of the display device 1. In this embodiment too, as in connection with Fig. 2, a trench may be formed between adjacent pixels. Furthermore, a trench may be formed on the connection layer 33 as described in connection with the Fig. 1A and Fig. 1B described a radiation conversion element may be arranged.

[0082] The Fig. The fourth embodiment shown in Figure 4 essentially corresponds to the one described in connection with the Fig. 1A and Fig.1B. In contrast, a plurality of semiconductor bodies 2 are arranged side by side on the carrier 5. For simplified representation, only the borders of the semiconductor bodies 2 and the metallization layers 31, 32 with the recesses 310 and the vias 320 are shown in the figure. The display device has, by way of example, four semiconductor bodies 2, each with 6 pixels 2a, 2b. However, the number of pixels per semiconductor body and the number of semiconductor bodies can be varied within wide limits. The first metallization layer 31 covers the carrier 5 over a large area, in particular between adjacent pixels 2a, 2b and between adjacent semiconductor bodies 2.The recesses 310 of the first metallization layer 31 are completely covered by the second metallization layer 32, so that below the semiconductor bodies 2 and between the semiconductor bodies 2, there is no direct optical path between the active regions 20 and the carrier with the control circuit 54. Only in regions of the carrier in which damage by radiation that impairs functionality is not to be expected, for example, outside an outer border of the semiconductor bodies 2, can the carrier 5 be formed free of both metallization layers.

[0083] During the manufacture of the display device 1, the semiconductor bodies 2 can be sequentially attached to the carrier 5. The carrier can be present in a wafer composite, which is subsequently singulated into the display devices. The distance between adjacent semiconductor bodies 2 can, in particular, be between 0.5 µm and 100 µm inclusive. In particular, the distance between adjacent pixels within a semiconductor body 2 can be as large as the distance between adjacent semiconductor bodies.

Claims

[1] Display device (1) with - at least one semiconductor body having a semiconductor layer sequence (2) which has an active region (20) provided for generating radiation and forms a plurality of pixels (2a, 2b), and - a control circuit (54), wherein - the control circuit (54) has a plurality of switches (55), each of which is provided for controlling at least one pixel (2a, 2b); - a first metallization layer (31) and a second metallization layer (32) electrically insulated from the first metallization layer are arranged between the drive circuit (54) and the semiconductor body; - the first metallization layer (31) and / or the second metallization layer (32) is electrically conductively connected to at least one of the pixels (2a, 2b); and - the first metallization layer (31) and the second metallization layer (32) are arranged to overlap one another such that the control circuit (54), in a plan view of the display device, is covered with at least one of the metallization layers (31, 32) at each point which overlaps with one of the pixels (2a, 2b) or is arranged between two adjacent pixels (2a, 2b). [2] Display device according to claim 1, wherein the first metallization layer (31) and the second metallization layer (32) are electrically conductively connected to at least one of the pixels (2a, 2b). [3] Display device according to claim 1 or 2, wherein the first metallization layer (31) or the second metallization layer (32) form a common contact for a plurality of pixels (2a, 2b). [4] Display device according to one of the preceding claims, wherein the second metallization layer (32) adjoins the semiconductor layer sequence (2) and is severed between two adjacent pixels (2a, 2b). [5] Display device according to one of the preceding claims, wherein the second metallization layer (32) is completely covered by the at least one semiconductor body in a plan view of the display device. [6] Display device according to one of the preceding claims, wherein the first metallization layer (31) has a recess (310) for each pixel (2a, 2b) in which the second metallization layer (32) is electrically conductively connected to the associated switch (55) of the control circuit (54). [7] Display device according to claim 6, wherein the recess (310) has an annular border. [8] Display device according to one of the preceding claims, wherein the display device comprises a carrier (5) on which the at least one semiconductor body is arranged. [9] Display device according to claim 8, wherein the drive circuit (54) is integrated into the carrier (5). [10] Display device according to claim 8, wherein the drive circuit (54) is arranged between the at least one semiconductor body and the carrier (5). [11] A display device according to claim 10, wherein the drive circuit (54) is deposited on the semiconductor body. [12] A display device according to claim 10 or 11, wherein the drive circuit (54) comprises a polycrystalline semiconductor material. [13] Display device according to one of claims 8 to 12, wherein a plurality of semiconductor bodies (2) each having a plurality of pixels (2a, 2b) is arranged on the carrier (5). [14] Display device according to claim 13, wherein the first metallization layer (31) and the second metallization layer (32) are arranged overlapping one another such that the carrier (5) is covered with at least one of the metallization layers (31, 32) at each location overlapping one of the semiconductor bodies or arranged between two adjacent semiconductor bodies when viewed from above the display device. [15] Display device according to one of claims 8 to 14, wherein a growth substrate (28) for the semiconductor layer sequence (2) is removed and the carrier mechanically stabilizes the semiconductor layer sequence. [16] Display device according to one of the preceding claims, wherein - the active region (20) is arranged between a first semiconductor layer (21) and a second semiconductor layer (22); and - the semiconductor layer sequence (2) has at least one recess (25) which extends from a rear side (27) of the semiconductor layer sequence (2) facing the drive circuit (54) through the active region (20) into the first semiconductor layer (21) and is provided for electrically contacting the first semiconductor layer (21). [17] Display device according to one of claims 1 to 15, wherein the pixels (31, 32) are electrically contacted from a radiation exit surface (29) facing away from the control circuit. [18] Display device according to one of the preceding claims, wherein the active area extends continuously over a plurality of pixels. [19] Display device according to one of claims 1 to 17, wherein the active region (20) is divided into a plurality of segments (20a, 20b), each forming a pixel, the segments emerging from the common semiconductor layer sequence (2). [20] Display device according to one of the preceding claims, wherein a radiation conversion element (6) is arranged on a side of the semiconductor layer sequence (2) facing away from the control circuit (54).

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