Method for manufacturing an optoelectronic semiconductor component and optoelectronic semiconductor component
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- OSRAM OPTO SEMICON GMBH & CO OHG
- Filing Date
- 2012-10-09
- Publication Date
- 2026-07-23
AI Technical Summary
Existing optoelectronic semiconductor components face challenges in achieving high efficiency with large operating currents, particularly due to the droop effect, and require complex electrical contacting and mechanical stabilization.
A method involving the production of radiation-active islands with a semiconductor layer sequence on a growth substrate, followed by the application of a separating layer and a carrier substrate, and detachment of the growth substrate using laser radiation or mechanical force, allowing for flexible and efficient electrical contacting and mechanical stabilization.
Enhances efficiency by reducing mechanical stress and simplifying electrical contacting, enabling flexible carrier systems and improved performance under high current conditions.
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Abstract
Description
[0001] A method for manufacturing an optoelectronic semiconductor component is described. Furthermore, an optoelectronic semiconductor component manufactured using this method is described.
[0002] One problem to be solved is to specify an optoelectronic semiconductor component that exhibits high efficiency at large operating currents.
[0003] This problem is solved, among other things, by a method and by an optoelectronic semiconductor component with the features of the independent claims. Preferred embodiments are the subject of the dependent claims.
[0004] According to at least one embodiment, the method is configured for manufacturing an optoelectronic semiconductor component. The semiconductor component is, for example, a light-emitting diode (LED). In particular, the semiconductor component is configured to generate ultraviolet radiation, visible light, and / or near-infrared radiation during operation.
[0005] According to at least one embodiment, the method comprises the step of generating radioactive islands. These islands have a sequence of semiconductor layers. The semiconductor layer sequence is preferably based on a III-V compound semiconductor material. The semiconductor material is, for example, a nitride compound semiconductor material such as Al n In 1-n-m Ga m N or a phosphide compound semiconductor material such as Al n In 1-n-m Ga m P or also an arsenide compound semiconductor material such as Al n In1-n-m Ga m As, where 0 ≤ n ≤ 1, 0 ≤ m ≤ 1, and n + m ≤ 1. The semiconductor layer sequence can contain dopants and additional components. For the sake of simplicity, however, only the essential components of the crystal lattice of the semiconductor layer sequence, i.e., Al, As, Ga, In, N, or P, are specified, even though these may be partially replaced and / or supplemented by small amounts of other substances. Preferably, the semiconductor layer sequence is based on AlInGaN.
[0006] According to at least one embodiment, the islands are produced directly or indirectly on a growth substrate. The growth substrate is, for example, a sapphire substrate or a silicon substrate. The islands are produced, for example, by self-organized, three-dimensional growth, by selective growth on the growth substrate using a growth mask, or by overgrowth of three-dimensional structures. Such three-dimensional structures can be produced, for example, by etching from a two-dimensional layer.
[0007] According to at least one embodiment, the islands each have one or more active zones. The active zone is preferably a component of the semiconductor layer sequence and is located, for example, between a p-type layer and an n-type layer of the semiconductor layer sequence. The active zone can be a single, contiguous region of the semiconductor layer sequence with physical properties that are constant perpendicular to a principal axis within the manufacturing tolerances. In the case of core-shell structures, the composition and / or thickness of the active zones can change gradually or abruptly. Different crystal facets along core-shell structures can also result in differences in the configuration of the active zone. The thickness of the active zone in core-shell structures is preferably at least 2 nm and / or at most 40 nm. In axial structures, the thickness of the active zone can also be up to 1000 nm.The active zone can be a single quantum well structure or a multiple quantum well structure.
[0008] According to at least one embodiment, the mean diameter of the islands, viewed from above the growth substrate and after completion of the islands, is at least 50 nm, at least 100 nm, or at least 200 nm. Alternatively or additionally, the mean diameter is at most 10 µm, at most 5 µm, at most 3 µm, or at most 2 µm. Viewed from above, the islands have, for example, a round or polygonal base, in particular a hexagonal base.
[0009] According to at least one embodiment, the method comprises the step of generating a separating layer, either directly or indirectly, on a side of the islands facing the growth substrate. The separating layer is designed to allow the islands to detach from the growth substrate. The separating layer can be flush with the islands in the direction of the growth substrate and extend along the base or attachment points of the islands and / or a sacrificial layer of the islands.
[0010] According to at least one embodiment, the separating layer surrounds the islands, or at least a portion of the islands, as viewed from above the growth substrate. This applies particularly after the separating layer has been completed and / or structured, or after partial material removal from the separating layer following the application of separating layer material. For example, the separating layer is then formed as a continuous layer in which, viewed from above, a plurality of holes are formed, with the islands located within the holes of the separating layer and / or having grown out of the holes.
[0011] According to at least one embodiment, the method includes the step of applying a support substrate. Preferably, the support substrate is applied to a side of the islands facing away from the growth substrate. The support substrate can be in contact with the islands or separated from them by at least one intermediate layer. It is possible that the support substrate comprises electrical conductors or electrically conductive structures for supplying current to the islands. The support substrate can be a mechanically rigid substrate, for example made of a semiconductor material such as silicon, a ceramic, or a metal, or a mechanically flexible substrate, for example made of a metal foil or a plastic film.
[0012] According to at least one embodiment, the growth substrate is detached from the islands. This detachment is preferably achieved using laser radiation and / or etching and / or mechanical force.
[0013] According to at least one embodiment, the islands have a sacrificial layer on a side facing the growth substrate. The sacrificial layer is preferably a portion of the semiconductor layer sequence of the islands. Furthermore, the sacrificial layer acts, for example, as an absorber for laser radiation used during detachment from the growth substrate, or the sacrificial layer is at least partially destroyed during detachment of the growth substrate by etching or mechanical force. In particular, the sacrificial layer is a portion of the semiconductor layer sequence and / or the islands that is closest to the growth substrate. The sacrificial layer and the separating layer can be arranged in a common plane parallel to the growth substrate.
[0014] According to at least one embodiment, the islands are partially or completely detached from the growth substrate by the laser radiation, at least partially destroying the separating layer and / or the sacrificial layer, and / or by temporarily or permanently softening or liquefying the separating layer and / or the sacrificial layer, and / or at least partially decomposing it into a gaseous state. Additionally, it is possible for the separating layer and / or the sacrificial layer to be at least partially destroyed by mechanical force.
[0015] According to at least one embodiment, the separating layer serves as a sacrificial layer for an etching process during the removal of the growth substrate. The separating layer can then consist of a material that can be selectively etched to the surrounding layers. The islands can subsequently be separated from a buffer layer and / or the growth substrate, for example, by mechanical stress.
[0016] For example, the separating layer then comprises or consists of at least one of the following materials: Ag, ZnO, Al, Ti, Ni, SiO2.
[0017] According to at least one embodiment, the islands are mechanically separated from the growth substrate. Due to reduced mechanical stability of the islands at the point of attachment, for example, caused by a defect-rich area, the islands break at this point, also known as the base point, when sufficient mechanical force is applied. This mechanical force can be applied, for example, using ultrasound or shear forces, such as those caused by twisting the support substrate relative to the growth substrate. With mechanically flexible support substrates, a peeling process is also possible. Separation can be facilitated by a release layer designed for low adhesion or by another process mentioned here.
[0018] Stresses between the separation layer and the islands can also be used to separate them from the growth substrate. Such stresses can be created, for example, by introducing layers with a different coefficient of thermal expansion and corresponding temperature stress.
[0019] The aforementioned processes for separating from the growth substrate can also be combined; for example, a laser removal process that attacks defect-rich growth points of the islands can be followed by a selective etching process that removes the separation layer and thus releases the growth substrate.
[0020] The sacrificial layer can act as a predetermined breaking point, since it contains more defective material that is correspondingly more mechanically unstable and may also exhibit higher absorption compared to other layers of the islands.
[0021] In at least one embodiment, the method for manufacturing an optoelectronic semiconductor component is set up and comprises at least the following steps: A) Generating radioactive islands with a semiconductor layer sequence on a growth substrate, wherein the islands each have at least one active zone of the semiconductor layer sequence and the mean diameter of the islands, as seen from above on the growth substrate, is between 50 nm and 10 µm inclusive, B) Creating one or more separation layers on a side of the islands facing the growth substrate, wherein the at least one separation layer surrounds the islands all around, as seen from above on the growth substrate, C) Attaching a support substrate to a side of the islands facing away from the growth substrate, and D) Detachment of the growth substrate from the islands, for example by means of laser radiation, wherein at least part of the separating layer is destroyed and / or at least temporarily softened by the laser radiation during detachment.
[0022] The aforementioned process steps can be carried out in the specified order or in a different order. Step D) is particularly preferred to follow step C).
[0023] The efficiency of GaN-based light-emitting diodes (LEDs) is limited under operating current conditions by the so-called droop effect. This effect describes a significant decrease in efficiency with increasing current density. One way to achieve higher efficiencies at a constant current density within an active zone is through core-shell nano-LEDs or core-shell micro-LEDs. In these LEDs, the radiatively active area can be increased through structured, three-dimensional growth while maintaining the same surface area of the semiconductor chip.
[0024] However, chip processing, especially electrical contacting, is more complex for such core-shell nano-LEDs. A method described here simplifies both the electrical contacting and the mechanical stabilization of such components. This is achieved primarily through the separation process of the growth substrate, for example, using laser radiation and the separating layer. Removing the growth substrate also allows the use of flexible substrate materials.
[0025] In conventional inorganic semiconductor devices, a semiconductor layer sequence is realized by a continuous, thin, epitaxially fabricated layer sequence with lateral dimensions, viewed from above, ranging from several hundred micrometers to a few millimeters. To prevent defects such as cracks, the semiconductor layer sequence must be mechanically stabilized. However, due to the small lateral dimensions of the islands, no significant mechanical stresses occur within the islands of the described semiconductor device when bent, and cracking does not occur, thus enabling the realization of flexible substrate systems.
[0026] Optoelectronic semiconductor components with a core-shell structure are also described in publication DE 10 2012 101 718 A1. The disclosure content of this publication is included by reference.
[0027] According to at least one embodiment of the method, a buffer layer is created on the growth substrate. The buffer layer can be applied directly to the growth substrate. For example, the buffer layer is based on GaN, AlGaN, or AlN. It is possible for the buffer layer to have an increasing gallium content in the direction away from the growth substrate. The thickness of the buffer layer is, for example, at least 10 nm or at least 50 nm and / or at most 10 µm or at most 500 nm. The buffer layer can be doped or undoped.
[0028] According to at least one embodiment, the buffer layer is created as a two-dimensional layer. In other words, the buffer layer extends across the growth substrate as a continuous, unstructured layer (as seen from above) without any intended openings.
[0029] According to at least one embodiment, the separating layer is created directly or indirectly on a side of the buffer layer facing away from the growth substrate. The buffer layer can therefore be in contact with the separating layer or be spaced apart from it.
[0030] According to at least one embodiment, the buffer layer is completely removed no later than step D). After the step of removing the buffer layer and / or after the step of removing the growth substrate, adjacent islands are no longer connected to each other via a semiconductor material of the semiconductor layer sequence and / or the buffer layer. In particular, there is no material connection between adjacent islands, wherein this material connection is based on the same material as the islands.
[0031] According to at least one embodiment, step A) follows step B). Step A) precedes step C).
[0032] According to at least one embodiment, a masking layer is applied to the growth substrate and / or the buffer layer. The masking layer has a plurality of openings. The islands are grown starting from or out of these openings. For example, the masking layer is formed from silicon oxide, silicon nitride, titanium, or molybdenum. The mean thickness of the masking layer is preferably at most 150 nm, 50 nm, or 20 nm, and / or at least 0.5 nm or 2 nm.
[0033] According to at least one embodiment, the masking layer is formed by the separating layer. Alternatively, it is possible that the separating layer and the masking layer are formed from different layers and are made of different materials.
[0034] According to at least one embodiment, the masking layer is formed from a radiation-absorbing material. For example, the masking layer is then formed from silicon nitride, doped silicon oxide, titanium nitride, titanium oxide, or tungsten nitride. Alternatively, multilayer structures, such as those consisting of a nitrogen-based or oxygen-based dielectric and an absorbing metal or semiconductor, can also be used for the masking layer, for example, SiO2 / Ag or SiO2 / Si.
[0035] According to at least one embodiment, the separating layer is formed as an etching sacrificial layer. In this case, the separating layer is formed, for example, from Ag or ZnO.
[0036] According to at least one embodiment, the separating layer is located directly adjacent to the growth substrate. Alternatively, the separating layer may be located directly on a side of the buffer layer facing away from the growth substrate. It is possible that the separating layer may partially contact the islands and / or the semiconductor layer sequence.
[0037] According to at least one embodiment, step B) follows step A), and step C) follows step B). In other words, the separation view is then created after the radioactive islands have been generated.
[0038] According to at least one embodiment, the separating layer is partially or completely covered by an electrical contact layer prior to step C), as seen from a top view of the growth substrate. The electrical contact layer is configured to supply current to the islands. In particular, the electrical contact layer is a p-contact to the islands, which may be radiolucent.
[0039] According to at least one embodiment, the electrical contact layer touches the separating layer. For example, the electrical contact layer is then applied directly to the separating layer, either partially or across the entire surface.
[0040] According to at least one embodiment, the sacrificial layer of the islands is deposited directly on the growth substrate or directly on the buffer layer. The sacrificial layer can have a doping composition different from that of the other components of the semiconductor layer sequence. The sacrificial layer is preferably based on AlInGaN, AlGaN, or GaN, or on another compound semiconductor such as ZnO, Hf₂O, HfN, or ZrO. Likewise, the sacrificial layer can be formed from a metal such as Ni, Ti, or W, or from a metal alloy. The thickness of the sacrificial layer is, for example, at least 15 nm and / or at most 100 nm or at most 500 nm.
[0041] According to at least one embodiment, the sacrificial layer is designed to be partially or completely decomposed and / or at least temporarily softened by the laser radiation in step D). In other words, separation occurs in step D) at both the separation layer and the sacrificial layer. The growth substrate can then be completely detached from the islands and other material components that have been applied to the growth substrate.
[0042] According to at least one embodiment, the active zone is applied to an n-conducting layer of the islands, at least on one lateral surface, as viewed from above the growth substrate. The n-conducting layer is, for example, columnar, prism-shaped, cylindrical, frustoconical, or truncated pyramidal. The active zone is preferably applied at least to the lateral surfaces of the n-conducting layer. It is also possible for the active zone to be applied to a side of the n-conducting layer facing away from the growth substrate. On this side facing away from the growth substrate, the active zone can also be partially or completely removed after application.
[0043] According to at least one embodiment, the active zone in the completed islands is oriented perpendicular or substantially perpendicular to the support substrate. Each of the islands can then have an active zone in the form of a cylindrical shell.
[0044] According to at least one embodiment, the islands, in the direction away from the growth substrate, have a sequence consisting of the n-type conductive layer, the active zone, and the p-type conductive layer. The active zone is then oriented essentially parallel to the growth substrate and / or the support substrate. The active zone preferably does not cover, or does not significantly cover, the side faces of the n-type conductive layer.
[0045] According to at least one embodiment, the ratio of the islands' mean height to their mean diameter is at least one, at least five, or at least eight. Alternatively or additionally, this ratio is at most 100, at most 50, or at most 25. In other words, the islands are then elongated, column-like structures.
[0046] According to at least one embodiment, an area between adjacent islands is filled with a filling material. This filling preferably takes place before step C) and after steps A) and B). The filling material can be made of a mechanically rigid or a mechanically flexible material.
[0047] According to at least one embodiment, the filling material is electrically insulating. For example, the filling material is formed by silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, titanium oxide, silicon oxynitride, tellurium oxide, spin-on glass, benzocyclobutene, parylene, a silicone, or a polymer.
[0048] The filler material can completely fill the space between adjacent islands. The filler material can be applied in such a way that the islands are at least temporarily completely covered by the filler material, as seen from above the growing substrate.
[0049] According to at least one embodiment, the filling material is made of or comprises one or more optically active materials. For example, at least one phosphor is added to the filling material to convert primary radiation generated by the islands into a different secondary radiation. Furthermore, the filling material can provide optical isolation between adjacent islands. In this case, the filling material is preferably reflective and opaque. The filling material can also serve to scatter light.
[0050] According to at least one embodiment of the method, the upper surface of the islands facing away from the growth substrate is shaped conically or pyramidally before step C). Preferably, only the upper surface is shaped in this way, and the side surfaces of the islands are oriented essentially perpendicular to the growth substrate. The upper surface then has a smaller slope, differing from that of the side surfaces of the islands.
[0051] According to at least one embodiment, the upper surface protrudes above the filling material. The islands then partially protrude from the filling material.
[0052] According to at least one embodiment, the upper surface of the islands projects into an electrical contact layer. This contact layer is, for example, configured as an n-contact. The contact layer can be configured as a reflective layer or as a reflective stack of layers. Alternatively, the contact layer can also be made of a radiation-transparent material.
[0053] According to at least one embodiment, the support substrate is attached to the islands via the electrical contact layer. In other words, the electrical contact layer is located between the support substrate and the islands, mediating mechanical adhesion between the islands and the support substrate. The contact layer can be formed by a stack of several, preferably metallic, layers.
[0054] According to at least one embodiment, the electrical contact layer for contacting the p-type layer is applied over the entire surface of the semiconductor layer sequence. This step preferably takes place after steps A) and B) and before step C).
[0055] According to at least one embodiment, the electrical contact layer for contacting the p-type and / or n-type layers is made of a transparent, conductive oxide. This electrical contact is preferably formed onto the islands and surrounds them at least partially in a form-fitting manner. On a side of the islands facing the growth substrate and in areas between the islands, viewed from above, the electrical contact layer is preferably oriented parallel to the growth substrate.
[0056] According to at least one embodiment, the electrical contact layer is subsequently removed from the upper surfaces of the islands, particularly before step C). Optionally, electrical insulation can be applied to the contact layer in certain areas before step C).
[0057] According to at least one embodiment, the electrical contact layer, in particular the electrical contact for contacting the p-type layer, is applied at a distance from the separating layer. In particular, the electrical contact layer can be electrically insulated from the separating layer.
[0058] According to at least one embodiment, the electrical contact layer, in particular the contact layer for contacting the p-type layer, is designed such that this layer does not extend to the undersides of the islands facing away from the support substrate. In other words, the islands then project beyond the electrical contact layer in the direction of the growth substrate.
[0059] Furthermore, an optoelectronic semiconductor component is specified. The semiconductor component is manufactured using a method as described in connection with one or more of the embodiments mentioned above. Features of the method are therefore also disclosed for the semiconductor component and vice versa.
[0060] In at least one embodiment, the separating layer is at least partially found in the finished semiconductor component. The separating layer may exhibit traces of separation, for example, due to laser radiation.
[0061] According to at least one embodiment, the separating layer is in direct contact with the islands, with the electrical contact layer for contacting the p-conducting layer of the semiconductor layer sequence and / or with the filler material that is arranged between the adjacent islands.
[0062] According to at least one embodiment, individual islands or groups of islands can be controlled electrically independently of one another. This allows the islands or groups of islands to serve as preferably actively controllable pixels of a display.
[0063] Such an optoelectronic semiconductor component can be used, for example, as a light source in flexible displays. In such a light source, several of these semiconductor components can be assembled into a larger-area arrangement, for example using a so-called pick-and-place method.
[0064] The following section provides a more detailed explanation of a method and an optoelectronic semiconductor component described herein, with reference to the drawing and illustrated by exemplary embodiments. Identical reference numerals denote identical elements in the individual figures. However, the figures are not to scale; rather, individual elements may be exaggerated for clarity.
[0065] They show:
[0066] Fig. 1 to Fig. 8 and Fig. 13 schematic sectional views of process steps of a process described herein for the fabrication of optoelectronic semiconductor components described herein, and
[0067] Fig. 9 to Fig. 12 schematic representations of exemplary embodiments of the optoelectronic semiconductor components described herein.
[0068] In Fig. 1 is a manufacturing process for an optoelectronic semiconductor component 1 Illustrated in schematic sectional views. According to Fig. 1A is grown on a growth substrate 2 , for example a sapphire substrate or a silicon substrate, a buffer layer 7 deposited from undoped GaN, for example.
[0069] In Fig. 1B shows that the buffer layer 7 for example, through self-organized, three-dimensional growth of islands 4 to be isolated. The islands 4 preferentially exhibit a victim layer 30 consisting of an absorbing material and an n-conducting layer 31 , which is shaped, for example, in the form of a hexagonal prism. The sacrificial layer 30 as well as the n-conducting layer 31 are preferably formed from the same material system, for example from AlInGaN, in particular from GaN. The n-conducting layer 31is n-doped and forms a core of the islands 4 dar.
[0070] On the n-conducting layer 31 will, see Fig. 1C, an active zone 33 epitaxially deposited. The active zone 33 It is based, for example, on InGaN. It surrounds the active zone. 33 the n-conducting layer 31 as well as the victim class 30 preferably all around, both on a lateral surface 40 as well as on a growing substrate 2 upper side facing away 46 .
[0071] According to Fig. 1D is applied to the active zone 33 a p-conducting layer 35 deposited. The p-type conducting layer 35 is p-doped and preferably based on GaN or AlGaN.
[0072] In the procedural step, as in Fig. 1E shows the grown islands 4 as well as on the buffer layer 7 A separating layer across the entire surface 5separated. The separation layer 5 is preferably formed from a material that has a smaller band gap than the buffer layer 7 as well as the layers 31 , 35 Alternatively or additionally, the material of the separating layer is 5 to obtain a material that selectively adapts to the materials of the islands 4 and the buffer layer 7 etching allows it to have a different coefficient of thermal expansion than the materials of the islands 4 and the buffer layer 7 exhibits or that easily differs from the materials of the islands 4 and the buffer layer 7 This can be solved. For example, these coefficients of thermal expansion differ from each other by a factor of at least 2, 4, 6, or 10.
[0073] According to the in Fig. The process step shown in 1F is applied to the separating layer. 5a transparent, electrical contact layer 8a isolated. The contact layer 8a It is formed, for example, from indium tin oxide, or ITO for short, and represents a p-contact. The contact layer 8a is directly on the p-conducting layer 35 on the lateral surfaces 40 secluded.
[0074] In the procedural step, as in Fig. 1G is shown, it will be on the islands 4 a filling compound 9 raised, which also included spaces between the islands 4 preferably fills completely. The filling material 9 is formed, for example, from an electrically insulating material such as silicon dioxide.
[0075] According to Fig. 1H will be the filling 9 , the contact layer 8a as well as the semiconductor layer sequence 3 partially removed, so that the n-conducting layer 31 is exposed and the growth substrate 2far side 46 the islands 4 is produced. The growth substrate 2 far side from the filling 9 and the islands 4 is in the procedural step according to Fig. 1H preferably planar and flat in shape.
[0076] In Fig. 1I has been shown that the active zone 33 a passivation 93 is applied. Via passivation 93 is a transition between the p-type layer 31 towards the n-conducting layer 31 Protectable against electrical short circuits. Such passivation 93 This can be achieved, for example, by partially deactivating the p-type layer. 35 can be produced, in particular by targeted destruction of the p-conducting properties, for example by means of hydrogen plasma.
[0077] Then another electrical contact layer is added 8b applied, see Fig. 1J. The contact layer 8b can also be used as a mirror 96 to act and, for example, have a silver layer. Contrary to what is shown, the electrical contact layer can 8b formed by a stack of layers consisting of several different and, in particular, metallic layers.
[0078] As in Fig. 1K shown, is applied to the electrical contact layer 8b a carrier substrate 6 applied, for example by gluing or soldering.
[0079] Then, see Fig. 1L, using a laser radiation R the growth substrate 2 including the buffer layer 7 from the islands 4 and the islands 4 connecting filling 9 removed. The laser radiation R is directed onto the separating layer. 5 as well as on the victim layer 30 focused. The victim class 30 as well as the separating layer 5are partially destroyed and / or melted by the laser radiation R. Removal of the growth substrate. 2 This is preferably done with the aid of mechanical force.
[0080] As an alternative to a laser removal process, the separating layer and / or the sacrificial layer can be removed by means of a selective etching process and / or by stress caused by a difference in the thermal expansion coefficients of the separating layer. 5 and the buffer layer 7 The separation from the growth substrate can also be supported by mechanical force, for example by ultrasound.
[0081] In Fig. 1M is the finished semiconductor component 1 shown. Electrical contact points are used for external electrical contacting. 85attached. Electrical contact of the n-type layer is thus achieved via the electrical contact layer. 8b , which act as mirrors 96 can be shaped, as well as via the preferably transparent and radiation-permeable contact layer 8a , which are attached to the islands 4 is shaped and the islands 4 surrounding it, in a top view of the support substrate 6 seen. Alternatively, the electrical contact layer 8b and the carrier substrate 6 should be equally transparent to radiation.
[0082] As in all other embodiments, the islands 4 and / or in the filling 9 Optionally, a structure or roughening may be formed, for example to improve light extraction efficiency. For this purpose, the n-conducting layer can be shaped. 31 be partially removed.
[0083] Combined with Fig. 2 are different ways to manufacture the islands 4 schematically illustrated. According to Fig. 2A will be the islands 4 self-organized on the growth substrate 2 grown, whereby the buffer layer 7 is optional. The individual islands 4 They may have different heights and / or diameters. The active zone may be affected. 33 the respective islands 4 have a constant material composition and constant thickness within the manufacturing tolerances, so that the different islands 4 exhibit essentially the same spectral emission characteristics. Such islands 4 , as in Fig. 2A shown, are also in Fig. 1 can be seen. Alternatively, one can be viewed via the active zone. 33 Varying levels of indium, for example, are present, so that a spectrally broadband emission is possible.
[0084] Furthermore, it is possible that the islands 4 to grow in a self-organized manner, with the n-conducting layer 31 , the active zone 33 as well as the p-conducting layer 35 the semiconductor layer sequence 3 in the direction away from the growth substrate 2 follow one another, see Fig. 2B. The active zone 33 can therefore essentially grow in parallel with the growth substrate 2 be aligned. Are attached to a growing substrate. 2 far side of the n-conducting layer 31 If oblique facets, for example pyramid-like facets, are formed, the active zone can 33 to replicate a form of these facets and, for example, be shaped like a pyramid mantle.
[0085] According to the Fig. 2A and Fig. 2B constructed islands 4 are also in the Fig. 2C and Fig. to see in 2D. According to the Fig. 2C and Fig. 2D is on the growth substrate 2 or on the optional buffer layer 7 Each a masking layer 23 upset. The islands 4 grow out of openings in the masking layer 23 out. It is possible that the islands 4 the masking layer 23 partially covering each, in a top view of the growing substrate 2 seen.
[0086] Another production option for the islands 4 is in connection with the Fig. 2E and Fig. 2F shown. According to Fig. 2E is applied to the growth substrate 2 or on the buffer layer 7 a continuous, n-conducting layer 31 This n-conducting layer is generated. 31 The resulting structures are then structured, for example by etching. The active zone is subsequently applied to the resulting structures. 33 as well as the p-conducting layer 35 grew up, see Fig. 2F.
[0087] The subsequent procedural steps can each be carried out as described in connection with Fig. 1 shown.
[0088] As in all other embodiments, the islands 4 each regularly or irregularly on the growth substrate 2 It must be applied. The finished semiconductor component 1 Each one, for example, has at least 100, at least 1000, or at least 10000 of the islands. 4 on. A degree of coverage of the growth substrate. 2 with the islands 4 The area factor, also referred to as the surface area factor, is preferably, when viewed from above, at least 5%, at least 25%, or at least 50%. Alternatively or additionally, the area factor is at most 90%, at most 80%, or at most 75%. An area of the active zone 33 , in a direction perpendicular to the n-conducting layer 31 as well as to the p-conducting layer 35is, in particular in configurations according to the Fig. 2A, Fig. 2C and Fig. 2F, preferably larger than a surface of the growth substrate 2 The area factor can therefore be greater than 1, for example at least 1.5 or at least 3 or at least 5.
[0089] In the Fig. 3 to Fig. Seven are shown in cross-sectional views as variants of the design of the separating layer. 5 shown. Corresponding separating layers 5 can also occur in procedures such as those related to the Fig. 1 and Fig. 2 shown, use.
[0090] According to Fig. The separating layer is located in 3A. 5 directly on the growth substrate 2 . During the separation of the islands 4 from the growth substrate 2 Preferably, only the separating layer is removed. 5 and the optional sacrificial layer 30 destroyed and the growth substrate 2It remains intact. This means the growth substrate is intact. 2 Reusable.
[0091] According to Fig. 4A is the separating layer 5 simultaneously as a masking layer 23 formed and is partially located between the buffer layer 7 and the n-conducting layer 31 As in Fig. 4B shows both the buffer layer 7 as well as the growth substrate 2 removed. The masking layer 23 is therefore at least partially destroyed by the laser radiation R.
[0092] According to Fig. 5A is attached to the carrier substrate 2 far side of the masking layer 23 the separating layer 5 applied. This makes it possible to see Fig. 5B, that the masking layer 23 essentially unaffected by the laser radiation R at the growth substrate 2remains. Thus, the growth substrate is 2 including the masking layer 23 reusable, for example after cleaning.
[0093] It is possible that the at least partially destroyed, optional sacrificial layer 30 or, contrary to what is shown, the n-conducting layer 31 the openings in the masking layer 23 reshape.
[0094] According to the Fig. 6A and Fig. 6B is, unlike in Fig. 4 shown, which acts as a masking layer 23 serving separating layer 5 directly on the growth substrate 2 appropriate.
[0095] In Fig. The masking layer is located in position 7. 23 , on which the separating layer 5 is attached directly to the growth substrate 2 , unlike in connection with Fig. 5 shown.
[0096] In Fig. Eight further contact possibilities of the islands are shown in schematic cross-sectional views. 4 shown, each before the growth substrate was removed. 2 The separating layer 5 , the masking layer 23 as well as the buffer layer 7 They can each be designed in a way that is related to the figures. Fig. 1 to Fig. 7 is given.
[0097] According to Fig. 8A p-contacting is achieved via the layer 8a by means of the mirror 96 on the carrier substrate 6 side facing the growth substrate. n-contact is established via the side facing the growth substrate. 2 The side facing the growing substrate. 2 opposite side of the p-type layer 35 as well as the active zone 33 will be according to Fig. 8A not removed. The growth substrate will be removed. 2 preferably replaced by electrically conductive structures in Fig. 8A not drawn. The same applies to Fig. 8B.
[0098] According to the Fig. 8C and Fig. 8D is the top side 46 the n-conducting layer 31 for example, sharpened and pyramidally shaped by wet chemical etching. At a boundary between the top surface 46 and on the lateral surfaces 40 The passivation is located 93 The filling 9 essentially concludes flush with the passivation 93 and does not reach, or only slightly reaches, the top. 46 This brings the n-conducting layer closer. 31 through the electrical contact layer 8b on the carrier substrate 6 electrically contacted. The p-type conductive layer 35 is via the radiation-permeable electrical contact layer 8a , which are attached to the islands 4 is formed, shaped.
[0099] According to Fig. 8D is not a separate passivation. 93 not depicted, but a transition between the layers 31 , 35 as well as the active zone 33 are, in the direction away from the growth substrate 2 , from the filling 9 covered. The filling 9 thus covers the upper surfaces 46 the n-conducting layer 31 partially and is after the top surfaces have been created 46 introduced. According to Figure 8C, however, the filling can 9 before creating the top surfaces 46 It may be the filling. 9 can be applied in a single process step. Alternatively, the filling can be applied in a single step. 9 can also be applied in several process steps, possibly interrupted by further process steps.
[0100] In Fig. 8E shows that the individual islands 4They can have different heights. Planarization is preferably achieved by the electrical contact layer. 8b , which act as mirrors 96 It can be designed in various ways. The electrical contact layer 8a For p-contacting, a form-fit connection is preferably made by a thin passivation. 93a covered, which is a form of electrical contact layer 8a imitates. Optionally, it is located at least in some areas between the islands. 4 further passivation 93b , onto which the electrical contact layer then 8b for n-contacting in the direction away from the growth substrate 2 follows.
[0101] In the sectional views of the Fig. 9 are examples of the semiconductor component. 1 shown, which is a particularly mechanically flexible support substrate 6 exhibit. Compare to the Fig. 1 to Fig. Figure 8 shows the illustrations with respect to a growth direction of the semiconductor layer sequence. 3 Shown rotated by 180°.
[0102] The carrier substrate 6a , via which the n-contacting with the contact layer 8b The substrate used is flexible, for example a film based on a metal or plastic. The contact layer 8b is optionally designed as a mirror, as in all other embodiments.
[0103] On a carrier substrate 6a far side of the islands 4 A second, mechanically flexible support substrate is optional. 6b attached. The further carrier substrate 6b is preferably transparent to radiation.
[0104] According to Fig. 9B is the n-conducting layer 31 via the contact layer 8b and the further carrier substrate 6bcontacted Fig. 8A shown, can be used. The contact layers 8a , 8b are each equipped with electrical contact points 85 to an electrical, external contact of the semiconductor component 1 tied together.
[0105] According to Fig. In 9C, p-contacting occurs via the contact layer. 8a , which are attached to the islands 4 It is molded in the direction away from the support substrate. 6a follows the n-conducting layer 31 a passivation 93a , the undersides that were formerly facing the growth substrate 42 appropriate.
[0106] The electrical contact layer 8a , which may be composed of a layer formed before the removal of the growth substrate and a layer formed after the removal of the growth substrate, protrudes according to Fig. 9C optionally in the further carrier 6b inside. The next carrier 6b can be used as a coating on the filling 9 as well as to the islands 4 be upset. Contrary to what is shown, the islands may 4 facing side of the carrier 6b be flat.
[0107] In Fig. 9D is an electrical contacting system for the islands 4 , as in connection with Fig. 8B shown, illustrated.
[0108] In the Fig. 10 to Fig. Figure 12 contains sectional views in figure parts A and schematic top views of the optoelectronic semiconductor component in figure parts B. 1 shown. The electrical contact is set up as shown in connection with Fig. 9C is explained. However, all other contact types and contact layer configurations shown are also possible. 8a , 8b in connection with the Fig. 10 to Fig. 12 can be used.
[0109] According to Fig. 10 are the contact layers 8a , 8b each with continuous layers. All islands 4 They are therefore electrically connected in parallel and can be controlled electrically together.
[0110] In Fig. Figure 11 shows that the electrical contact layers 8a , 8b on opposite sides of the islands 4 They are located and each is designed in a striped shape, with the stripes oriented orthogonally to each other. This allows the individual islands to be... 4 Each of the track-like contact layers can be individually electrically controlled. 8a , 8b contacts a row or a column of the islands 4 , see Fig. 11B. In contrast to this, it is possible that the individual lanes may cover multiple rows and columns of the islands. 4contact them together.
[0111] In Fig. Figure 12 shows that the contact layers 8a , 8b each of the islands 4 are limited. This prevents the islands from being interconnected. 4 , for example, on an external, not shown mounting bracket, individualization is possible. Unlike shown, several of the islands can be used. 4 of connected contact layers 8a , 8b be covered, so that groups of islands 4 They can be switched electrically together. Between those located directly on the islands 4 located contact layers 8a , 8b Unillustrated conductor tracks can lead to a more complex interconnection of the islands. 4 appropriate.
[0112] In the sectional views according to the Fig. 13A and Fig. Figure 13B shows that the p-contact layer 8a from the separating layer5 is arranged at intervals. Between the separating layer 5 and the contact layer 8a There is an initial filling 9a The contact layer 8a So it's in the fillings 9a , 9b , together with passivization 93 , embedded. It is possible that only part of the active zone 33 is powered by electricity.
[0113] The invention described here is not limited by the description based on the exemplary embodiments. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes every combination of features in the patent claims, even if this feature or combination itself is not explicitly specified in the patent claims or exemplary embodiments. QUOTES INCLUDED IN THE DESCRIPTION
[0114] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature
[0115] DE 102012101718 A1
[0026]
Claims
[1] Method for manufacturing an optoelectronic semiconductor device ( 1 ) with the following steps: A) Creation of radioactive islands ( 4 ) with a semiconductor layer sequence ( 3 ) on a growth substrate ( 2 ), the islands ( 4 ) at least one active zone each ( 33 ) the semiconductor layer sequence ( 3 ) exhibit and have a mean diameter of the islands ( 4 ), in top view of the growth substrate ( 2 ) seen, between inclusive 50 nm and 10 µm, B) Creating at least one separating layer ( 5 ) on a growth substrate ( 2 ) facing side of the islands ( 4 ), where the separating layer ( 5 ) the islands ( 4 ) surrounds all around, in a top view of the growth substrate ( 2 ) seen, C) Applying a carrier substrate ( 6) on a growth substrate ( 2 ) far side of the islands ( 4 ), and D) Detaching the growth substrate ( 2 ) from the islands ( 4 ), where at least part of the separating layer is removed ( 5 ) is destroyed and / or at least temporarily softened. [2] Method according to the preceding claim, wherein a buffer layer is applied to the growth substrate ( 7 ) is generated, where the buffer layer ( 7 ) a continuous layer that appears unstructured when viewed from above, where the separating layer ( 5 ) on a growth substrate ( 2 ) opposite side of the buffer layer ( 7 ) is generated, where at the latest in step D) the buffer layer ( 7 ) is completely removed, so that neighboring islands ( 4 ) no longer via a semiconductor material of the semiconductor layer sequence ( 3) or the buffer layer ( 7 are connected to each other, and wherein in step D) the removal is carried out using laser radiation (R) and at least a part of the separating layer ( 5 ) is destroyed and / or at least temporarily softened by the laser radiation (R). [3] Method according to any of the preceding claims, wherein step A) follows step B) and precedes step C). [4] Method according to the preceding claim, in which the separating layer ( 5 ) a masking layer with a multitude of openings, the islands ( 4 ) grow out of these openings. [5] Method according to the preceding claim, wherein the separating layer ( 5 ) directly on the growth substrate ( 2 ) or directly adjacent to the growth substrate ( 2 ) opposite side of the buffer layer ( 7 ) is located. [6] Method according to any of the preceding claims, wherein step B) follows step A) and precedes step C). [7] Method according to the preceding claim, wherein before step C) the separating layer ( 5 ) at least partially from an electrical contact layer ( 8a ), which leads to an electric current flowing to the islands ( 4 ) is set up, is covered when viewed from above, with the electrical contact layer ( 8a ) the separating layer ( 5 ) touched. [8] Method according to at least claim 2, where the islands ( 4 ) on a growth substrate ( 2 ) facing side a sacrificial layer ( 30 ) exhibit, where the victim layer ( 30 ) a part of the semiconductor layer sequence ( 3 ) is and acts as an absorber for the laser radiation (R). [9] Method according to any one of the preceding claims, wherein the active zone (33 ) an n-conducting layer ( 31 ) the islands ( 4 ) at least on one lateral surface ( 40 ) surrounds it, as seen from above. [10] Method according to any one of the preceding claims, wherein the islands ( 4 ) are grown as columns, with a quotient of an average height of the islands ( 4 ) and an average diameter of the islands ( 4 ) between 1 and 100 inclusive. [11] Method according to any of the preceding claims, wherein an area between adjacent islands ( 4 ) with an electrically insulating filler ( 9 ) is refilled, where one of the growth substrate ( 2 ) facing away top side ( 46 ) the islands ( 4 ) before step C) is shaped conically or pyramidally, where the top side ( 46 ) the filling material ( 9 ) protrudes and is incorporated into an electrical contact layer ( 8b) protrudes into it, and where the carrier substrate ( 6 ) via the electrical contact layer ( 8b ) on the islands ( 4 ) is attached. [12] Method according to the preceding claim, wherein the filling mass ( 9 ) and the carrier substrate ( 6 ) are mechanically flexible. [13] Method according to one of the preceding claims, wherein an electrical contact layer is formed after steps A) and B) and before step C) ( 8a ) to a contacting of a p-conducting layer ( 35 ) the semiconductor layer sequence ( 3 ) is applied over the entire surface, where the electrical contact layer ( 8a ) produced from a transparent, conductive oxide and attached to the islands ( 4 ) is shaped, and where the electrical contact layer ( 8a ) from the upper sides ( 46 ) the islands ( 4 ) is removed. [14] Method according to the preceding claim, in which the electrical contact layer ( 8a ) from the separating layer ( 5 ) is applied at intervals and separated from the separating layer ( 5 ) is electrically insulated, where the electrical contact layer ( 8a ) not up to the carrier substrate ( 6 ) facing undersides ( 42 ) of the islands. [15] Optoelectronic semiconductor device ( 1 ), that is produced by a method according to one of the preceding claims, where the separating layer ( 5 ) at least partly directly on the islands ( 4 ) and / or at an electrical contact layer ( 8a ) for contacting a p-type layer ( 35 ) the semiconductor layer sequence ( 3 ) and / or on a filling compound ( 9 ), which are between neighboring islands ( 4 ) is arranged, is located. [16] Optoelectronic semiconductor device ( 1 ) according to the preceding claim, that is set up for a display where some of the islands ( 4 ) or groups of islands ( 4 ) can be controlled electrically independently of each other, so that through the islands ( 4 ) or groups of islands ( 4 ) pixels of the display are formed.