Optoelectronic semiconductor chip and method for manufacturing an optoelectronic semiconductor chip

Abstract

Optoelectronic semiconductor chip with: - a semiconductor layer sequence (204) with a radiation extraction side (102, 910) for extracting electromagnetic radiation that can be generated in an active zone (904) of the semiconductor layer sequence (204); - a contact connection (104, 1000);- a contact material (210, 912) applied to the radiation output side (102, 910) and - a conductive connection (106, 500, 914) applied to the contact material (210, 912) and connected to the contact terminal (104, 1000), wherein a dielectric is arranged at least section by section between the conductive connection (106, 500, 914) and the radiation output side (102, 910) such that the conductive connection (106, 500, 914) is spaced away from the radiation output side (102, 910) and at an interface with the dielectric, part of the radiation is reflected back into the semiconductor layer sequence due to total internal reflection and can be coupled out via another location of the radiation output side (102, 910) above which no section of the is arranged in a conductive connection (106, 500, 914).

Description

[0001] The present invention relates to an optoelectronic semiconductor chip and a method for manufacturing an optoelectronic semiconductor chip.

[0002] An optoelectronic semiconductor chip is a sequence of layers produced on a substrate using a semiconductor process. This involves a semiconductor, for example, a III-V semiconductor. The semiconductor layer sequence can consist of epitaxial layers grown on the substrate. The substrate may contain materials such as SiC, sapphire, Ge, Si, GaAs, GaN, or GaP. The epitaxial layers may contain quaternary semiconductors, such as AlInGaN for a blue or green emission spectrum in the visible range, or AlInGaP for a green to red emission spectrum in the visible range. These semiconductors can also exhibit emission spectra in the non-visible range, for example, in the UV range. The epitaxial layer can also contain quinternary semiconductors. One such semiconductor is AlGaInAsP, which can be used to emit radiation in the infrared range.

[0003] The semiconductor layer sequence contains a suitable active zone for generating electromagnetic radiation. The active zone can contain a double heterostructure or a quantum well structure, such as a single quantum well (SQW) or multi quantum well (MQW).

[0004] In a light-emitting diode (LED), a homogeneous current density in the active zone, e.g., at the pn junction, is desirable for high efficiency (i.e., a high ratio of emitted electromagnetic radiation to input power), a long lifetime, and homogeneous radiation. A particular problem arises when current is supplied from the side where the light is extracted (radiation extraction side). Current injection on the radiation extraction side is typically achieved via contact pads deposited on the semiconductor. A dense network of contact pads can optimize the electrical properties of an LED. However, these pads are detrimental to the optical behavior of such a component because they lead to shadowing or absorption. Since light travels relatively long distances in a thin-film LED before being extracted, light can be absorbed at the contact pads.The efficiency of the LED is reduced.

[0005] Another problem arises because a voltage drop occurs within a contact bridge due to the finite conductivity. The remaining forward voltage across the active zone therefore varies across the chip area.

[0006] The present invention addresses the problem of providing an optoelectronic semiconductor chip with improved efficiency in light extraction, or of specifying a method for manufacturing such a semiconductor chip.

[0007] This problem is solved by an optoelectronic semiconductor component or a method for manufacturing an optoelectronic semiconductor component according to independent claims 1 and 10, respectively.

[0008] Further developments and advantageous embodiments of the optoelectronic semiconductor chip or of the method for manufacturing an optoelectronic semiconductor chip are specified in the dependent patent claims. EXAMPLE EXECUTION FORMS

[0009] Various embodiments of the optoelectronic semiconductor chip have a radiation extraction side and a contact terminal. A contact material is applied to the radiation extraction side. The optoelectronic semiconductor chip has a conductive connection applied to the contact material and connected to the contact terminal.

[0010] This design on the radiation output side results in the connection being divided into two structures. The contact material serves to induce a current in the semiconductor layer sequence of the optoelectronic semiconductor chip. The conductive connection, which links the contact point (e.g., a bond pad or a lead via a foil) to the contact material, serves to distribute the current on the radiation output side.

[0011] The functional partitioning allows, in particular, the contacting of the semiconductor layer sequence to be limited to locations where it is advantageous for the function of the optoelectronic semiconductor chip. This can be achieved, for example, by arranging the contact material in such a way as to ensure the most homogeneous power supply possible via the radiation output side. The contact material can be optimized with respect to its contact resistance on the radiation output side. Simultaneously, the conductive connection can be optimized to exhibit good transverse conductivity. It can also be optimized with respect to its influence on the optical behavior of the optoelectronic device. For example, this can result in fewer optically passive areas on the radiation output side.

[0012] In other words, a fundamental principle of the invention is that by functionally separating the electrical contacting of the semiconductor chip from the power supply distribution, greater flexibility in optimizing for different requirements is allowed. For example, the electrical contacting can be optimized with regard to homogeneous current induction and low contact resistance. The power supply can be optimized, in particular, with regard to low lead resistance and minimal shading of the radiation output side or low absorption of the radiation emitted by the semiconductor layer sequence. In one embodiment, the area of ​​the contact material, projected onto the radiation output side, is smaller than the area of ​​the conductive connection.

[0013] Materials with high electrical conductivity are suitable for the conductive connection. Metals or metal alloys containing materials such as Al, Ag, Au, Cu, Ti, Pt, etc., are conceivable. Alloys like AuGe can also be used. It is also conceivable that multilayer metallization could be applied as a conductive connection to reduce diffusion processes; for example, a layer of TiWN could be applied to the radiation output side as a diffusion barrier. A gold layer could then be applied to this diffusion barrier as the conducting material.

[0014] Metals with a high reflection coefficient for the emitted radiation can be used as contact materials. Good contact resistance between the contact material and the semiconductor materials used in the optoelectronic semiconductor chip is also important. Suitable contact materials include metals such as Ag, Ti, Pt, and Au; alloys such as AuGe or AuZn; and transparent conductive oxides (TCOs) such as indium tin oxide (ITO). Good adhesion of the contact material to the semiconductor layer sequence can be achieved, or, conversely, interference with the semiconductor layer sequence can be avoided by reducing the formation of defects. Suitable measures and a wide variety of other suitable materials are known to those skilled in the art.

[0015] A dielectric is a weakly or non-conductive, non-metallic substance whose charge carriers are generally not freely mobile. Other properties can also be considered when selecting a dielectric. For example, it is advantageous for the dielectric to be transparent in the wavelength ranges in which the optoelectronic semiconductor emits radiation. The optical refractive index can also be relevant for dielectric selection. The dielectric can be applied as a dielectric layer. For example, the following materials are used as dielectrics in optoelectronic semiconductors: – Silicon nitride – Silicon dioxide; – Silicon oxynitride; – Aluminum oxide;

[0016] In one embodiment, the conductive connection comprises a conductor web structure. This allows for the creation of various geometries that permit a specific distribution of the supplied electric current on the radiation output side.

[0017] In one embodiment, the conductive connection comprises a transparent conduction layer. This means the conductive connection has little impact on radiation extraction via the radiation extraction side. Typically, the transparent conduction layer comprises a transparent conductive oxide (TCO), such as ITO.

[0018] In one embodiment, a dielectric is provided at least partially between the conductive connection and the radiation extraction side. This separates the conductive connection from the radiation extraction side. Most of the radiation is reflected back into the semiconductor layer sequence due to total internal reflection at the interface with the dielectric. This radiation can be extracted via another location on the radiation extraction side, above which no section of the conductive connection is located.

[0019] In one embodiment, the contact material is distributed on the radiation extraction side in such a way as to achieve the most homogeneous current density possible across the semiconductor chip. Such a distribution, for example, compensates for a voltage drop in the conductive connection. The distribution allows the contact resistance to the radiation extraction side to be controlled. As an optimization goal, the most uniform possible current injection across the radiation extraction side can thus be pursued.

[0020] In one embodiment, the contact material has a plurality of separate contact areas, in particular contact points. This allows for a suitable distribution of the contact material on the radiation extraction side.

[0021] In one embodiment, the contact points are unevenly distributed across the radiation extraction side. In another embodiment, the contact points have different sizes. Both measures are suitable for adjusting the current distribution on the radiation extraction side according to different optimization goals.

[0022] Various embodiments of the method for manufacturing an optoelectronic semiconductor component include the following steps: – Providing a semiconductor layer sequence with a radiation extraction side; – Applying a contact material to the radiation output side; – Applying a conductive compound to the contact material.

[0023] In various embodiments, a dielectric and / or conductive layer is first applied to the radiation output side. Both layers are advantageously transparent to radiation generated in the semiconductor layer sequence. In various embodiments, the applied layer is partially opened, for example by a photolithographic process and etching, and inserted into the opening of the contact material for contacting the radiation output side. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Various embodiments of the solution according to the invention are explained in more detail below with reference to the drawings. In the figures, the first digit(s) of a reference numeral indicate the figure in which the reference numeral is first used. The same reference numerals are used for similar or similarly acting elements or properties in all figures.

[0025] They show:

[0026] Fig. 1 the schematic representation of a top view of a first embodiment of an optoelectronic semiconductor chip;

[0027] Fig. 2. The schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip of the Fig. 1 along a section axis AA;

[0028] Fig. 3. The schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip of the Fig. 1 along a cutting axis BB;

[0029] Fig. 4 the schematic representation of a top view of a second embodiment of an optoelectronic semiconductor chip;

[0030] Fig. 5 the schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip of the Fig. 4 along a cutting axis AA;

[0031] Fig. 6. The schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip of the Fig. 4 along a cutting axis BB;

[0032] Fig. 7. The schematic representation of a variant of the semiconductor layer structure of the optoelectronic semiconductor chip of the Fig. 4 along a cutting axis AA;

[0033] Fig. 8 the schematic representation of the variant of the semiconductor layer structure of the optoelectronic semiconductor chip of the Fig. 4 along a cutting axis BB;

[0034] Fig. 9 the schematic representation of a semiconductor layer structure of a third embodiment of an optoelectronic semiconductor chip;

[0035] Fig. 10 the schematic representation of a top view of the third embodiment of an optoelectronic semiconductor chip;

[0036] Fig. 11. A schematic representation of a top view of the third embodiment of an optoelectronic semiconductor chip, omitting the conductive connection and the contact terminal; and

[0037] Fig. 12 the schematic representation of a process for manufacturing an optoelectronic semiconductor chip. EXECUTION EXAMPLES OF THE OPTOELECTRONIC SEMICONDUCTOR CHIP

[0038] Fig. Figure 1 shows a schematic representation of a top view of a first embodiment of an optoelectronic semiconductor chip. 100 The semiconductor chip 100 has a radiation output coupling side 102 . Via the radiation extraction side 102 Radiation is extracted that is generated in an active region of the semiconductor chip. (See radiation extraction page.) 102An electric current is also applied, causing the emission of electromagnetic radiation in the active zone. The electric current is applied via a contact connection. 104 supplied and via a conductive connection 106 on the radiation output side 102 distributed. The contact connection 104 For example, it is designed as a bond pad that can be connected to a bond wire. The conductive connection 106 An example is a conductor bridge structure in the form of an applied metallization. The conductive connection 106 It serves to distribute the electric current so that it is distributed as homogeneously as possible across the radiation coupling side. 102 into the semiconductor layer sequence of the optoelectronic semiconductor chip 100 can be imprinted. For this, a conductive connection is required. 106with a semiconductor layer sequence of the optoelectronic semiconductor chip 100 connected. This connection is established using the Fig. 2 and the Fig. 3 described in more detail.

[0039] Fig. Figure 2 shows the schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip. 100 along a sectioning axis AA. The optoelectronic semiconductor chip 100In the illustrated embodiment, the chip is designed as a thin-film LED chip. This design is presented schematically below. A basic principle of a thin-film LED chip is described, for example, in publication [1], the disclosure of which is hereby incorporated into this description by reference. Further examples of a thin-film LED chip are known from publications [2] and [3], the disclosure of which is also hereby incorporated into this description by reference.

[0040] The semiconductor chip 100 has an electrically conductive contact layer 200 Typically, it comprises a metal or a sequence of conductive materials, for example, a sequence containing one or more metals or a TCO. The electrically conductive contact layer 200 can be found in one of the Fig. It can be applied to two substrates not shown, such as silicate glass, a Ge substrate, or a silicon substrate. It can also be self-supporting, as shown in the exemplary embodiment. In the exemplary embodiment, the contact layer 200 at the same time in the wave range of the optoelectronic semiconductor chip 100 emitted radiation highly reflective, so that the contact layer 200 It also serves as a reflector layer. It is also possible that the contact layer... 200 An additional thin, electrically conductive reflector layer is applied. Possible materials for the contact layer include... 200 Doped semiconductors and metallic materials are suitable options. For example, a silver layer can be used as a contact layer. 200 be used.

[0041] On the contact layer 200 is a separating layer 202 applied. The separating layer 202It contains a dielectric material, such as SiN or SiO2. It separates the contact layer. 200 from a semiconductor layer sequence 204 . In this process, the contact layer 200 and the semiconductor layer sequence 204 from each other through the separating layer 202 electrically insulated in the semiconductor layer sequence 204 When an electric current is applied, electromagnetic radiation is generated. This can be achieved using a sequence of semiconductor layers. 204 a pn junction, a double heterostructure, or a quantum well structure such as a single quantum well (SQW) or multi quantum well (MQW) for radiation generation. In Fig. 2 is a pn transition with a depletion zone 206 hinted at.

[0042] On the semiconductor layer sequence 204 is a passivation layer 208 applied. Via the passivation layer 208is located in an active zone of the semiconductor layer sequence 204 generates emitted radiation. The passivation layer 208 covers the radiation output side 102 On the passivation layer 208 is the contact connection 104 attached. The contact connection 104 is from the semiconductor layer sequence 204 through the passivation layer 208 Electrically insulated. Furthermore, the passivation layer can also serve optical functions, such as anti-reflective coating. This advantageously prevents current flow from the contact terminal. 104 into the semiconductor layer sequence 204 up and it is located directly below the contact point 104 No radiation is generated. Radiation is absorbed at the contact point. 104 is further enhanced by a reflection at the passivation layer 208This reduces the overall efficiency of the optoelectronic semiconductor chip. 100 increased.

[0043] On the passivation layer 208 is also the conductive connection 106 applied. In some places below the conductive connection. 106 The passivation layer is open. There are contact points in the openings, for example, a contact point. 210 arranged. Via the contact point 210 will the conductive connection 106 with the semiconductor layer sequence 204 electrically connected. All contact points thus serve to supply an electric current into the semiconductor layer sequence. 204 Separately, it is the function of the conductive connection. 106 , the electric current on the radiation coupling side 102 to distribute.

[0044] Both the conductive connection 106, as well as the contact points, such as the contact point 210 , should include materials with high electrical conductivity. For example, they can be metals, metallic alloys, or doped semiconductor materials.

[0045] The contact points are defined by the conductive connection 106 completely covered, so that they pass through this and the passivation layer 208 is encapsulated. This protects the contact points from degradation caused by external influences, such as oxidation.

[0046] The distances between the contact points are shown as constant and of equal length. However, in other embodiments, they can vary across the area of ​​the radiation output side. 102 vary to compensate for a voltage drop along the conductive connection 106 to compensate in such a way that a homogeneous current density is achieved across the chip area.

[0047] In some embodiments, the sizes of the contact points are not homogeneous, but vary across the surface of the radiation coupling side. 102 This ensures that the area of ​​the radiation output side is covered. 102 a current density that is as homogeneous as possible in the semiconductor layer sequence 204 is imprinted.

[0048] The conductive connection 106 forms together with the contact points, including the contact point 210 a first electrode of the optoelectronic semiconductor chip 100 This electrode can be the anode or the cathode, for example depending on the arrangement of a pn junction in the semiconductor layer sequence. 204 The design of the second electrode of the optoelectronic semiconductor chip 100 will be based on the representation in Fig. 3 clearly.

[0049] Fig. Figure 3 shows the schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip. 100 along a section axis BB. The semiconductor layer structure is essentially identical to the layer sequence of the section along the section axis AA, as shown in Fig. 2 is shown. In contrast to the section along the cutting axis AA, however, in section BB the separation layer is 202 Openings are provided within which a bonding layer 300 is introduced. The bonding layer 300 connects the contact layer 200 electrically with the semiconductor layer sequence 204 . Together with the contact layer 200 forms the bonding layer 300 so that the second electrode of the optoelectronic semiconductor chip 100 . At points below the conductive connection 106 and therefore also below the contact points, for example the contact point 210is not a bonding layer 300 intended, rather the contact layer 200 there through the separating layer 202 from the semiconductor layer sequence 204 electrically insulated. This creates a barrier below the conductive connection. 106 in the semiconductor layer sequence 204 No radiation is produced. Radiation is therefore generated particularly in areas where the radiation can be readily extracted via the radiation extraction side. 102 can be coupled out. But the first electrode is also optimized from an optical point of view. For example, the conductive connection 106 mostly through the passivation layer 208 underlined, as from the Fig. 1 to Fig. 3 becomes clear. The one below the conductive connection 106Radiation generated in the surrounding area does not reach the conductive connection due to total internal reflection and therefore cannot be absorbed there. This reduces optical losses. Instead, the reflected radiation is reflected back into areas from which it is highly likely to be absorbed via the radiation coupling side. 102 is coupled out. This reduces optical losses. By choosing a material for the contact points that has high reflectivity for the semiconductor layer sequence. 204 The generated radiation also increases the overall optical efficiency of the optoelectronic semiconductor chip. 100 increased. A large portion of the generated radiation is extracted via the radiation output side. 102 decoupled.

[0050] This involves providing a separating layer. 202 not absolutely necessary. The semiconductor layer sequence 204 can be fully connected to the bonding layer300 or directly to the contact layer 200 adjacent without a separating layer 202 or a connecting layer 300 must be provided for. In this case, the entire radiation output coupling side will be used. 102 opposite side of the semiconductor layer sequence 204 A current was imprinted. Solely through the measures on the radiation extraction side. 102 It already achieves greater efficiency than known optoelectronic semiconductor chips.

[0051] Fig. Figure 4 shows a schematic top view of a second embodiment of an optoelectronic semiconductor chip. The optoelectronic semiconductor chip 400 differs significantly from the first embodiment of the Fig. 1 to Fig. 3 by the fact that on the radiation output side 102A transparent lead layer is applied as a conductive connection. On the radiation output side 102 They also include a contact connection and several contact points, for example a contact point 210 , applied. The functionality of the supply layer is described in Fig. 5 clearly.

[0052] Fig. Figure 5 shows the schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip according to the second embodiment of the Fig. 4 along a section axis AA. The setup differs from the first embodiment, particularly on the radiation output side. 102 . In the Fig. The second embodiment shown in section 5 is based on the semiconductor layer sequence 204 a transparent supply layer 500 applied. The transparent supply layer 500It serves for current distribution and allows the extraction of the data in the semiconductor layer sequence. 204 generated electromagnetic radiation. The transparent lead-in layer 500 The material is transparent and conductive in the area of ​​the generated radiation. It can be inorganic or organic. A typical material is a metal oxide, such as ITO.

[0053] The supply layer 500 covers the semiconductor layer sequence 204 , in some cases a contact material between the supply layer 500 and the semiconductor layer sequence 204 in the form of contact points, such as the contact point 210 The contact points comprise a highly conductive material and, as in the first embodiment, serve to supply the electric current to the semiconductor layer sequence. 204Due to the low contact resistance between the contact points and the semiconductor layer sequence, a significant portion of the electric current can be supplied. This is determined by the density and distribution of the contact points on the radiation extraction side. 102 The profile of the current imprinting into the semiconductor layer sequence can also be determined by the size of the contact points. 204 can be influenced. The aim is to achieve the most homogeneous current injection possible, in order to produce a homogeneous luminous pattern on the radiation output side. 102 to generate. The contact points allow for optimized current injection, while the current distribution is handled via the transparent supply line layer. 500 This has been done.

[0054] Depending on the size of the contact points, shadowing caused by these points can have varying effects on the luminous pattern. Using a transparent lead wire allows for a dense distribution of smaller contact points, for example, to achieve the most homogeneous luminous pattern possible. This also results in a significantly lower current distribution in the upper layer of the semiconductor layer sequence. 204 , for example in an n-doped layer, this is necessary. This allows for a particularly small layer thickness of the semiconductor, which can reduce manufacturing costs, especially in the case of epitaxial growth of the semiconductor layer sequence.

[0055] In the Fig. 6 is the contact point 104 detectable on the optoelectronic semiconductor chip. Fig. Figure 6 shows the schematic representation of the semiconductor layer structure of the optoelectronic semiconductor chip according to the second embodiment of the Fig. 4 along a cutting axis BB. It can be seen that the contact connection 104 on the transparent supply layer 500 is applied. This separates the supply layer. 500 the contact connection 104 from the semiconductor layer sequence 204 This prevents the direct current flow from the contact terminal. 104 into the semiconductor layer sequence 204 reduced. Below the contact connection, on the side facing the contact layer, is... 200 the separating layer 202 Proceed below the contact point. 104 Therefore, no luminescence is generated. This results in unnecessary absorption at the contact point. 104 reduced. This increases the efficiency of the optoelectronic semiconductor chip.

[0056] The Fig. Figure 7 shows a schematic representation of a variant of the semiconductor layer structure of the optoelectronic semiconductor chip of the Fig. 4 along the cutting axis AA. The variant of Fig. 7 differs from the variant of Fig. 5 and Fig. 6 by the fact that between the supply layer 500 and the semiconductor layer sequence 204 a passivation layer 208 is planned. In the passivation layer 208 Openings are provided in each of which there is a contact point, for example a contact point 210 , is introduced. This makes the supply layer 500 via the contact points with the semiconductor layer sequence 204 electrically connected. The current is injected on the radiation output side. 102 via the contact points.

[0057] Based on the Fig. 8 also makes it clear how the bonding layer 300can be changed. This variation is conceivable in connection with all embodiments of the optoelectronic semiconductor chip, even if they are in Fig. Figure 8 is shown in connection with the second embodiment. The bonding layer 300 In this variation, the contact layer connects over a large area. 200 with the semiconductor layer sequence 204 This contact is particularly relevant in connection with a transparent lead-in layer. 500 This is particularly advantageous because it results in a homogeneous and bright radiation distribution on the radiation output side. 102 is achieved.

[0058] Fig. Figure 9 shows a schematic representation of a cross-section through a third embodiment of an optoelectronic semiconductor chip. The optoelectronic semiconductor chip 900The active zone in the semiconductor layer sequence contains a quantum well structure. This is illustrated using a GaN / InGaN / GaN layer sequence as an example.

[0059] The optoelectronic semiconductor chip 900 contains a contact layer 200 , on which a sequence of semiconductor layers is arranged. The contact layer 200 serves as an electrode for the optoelectronic semiconductor chip 900 Accordingly, it contains a material with low contact resistance, such as a metal, e.g., silver (Ag). A doped semiconductor material is also conceivable. Because the side of the optoelectronic semiconductor chip 900 , on which the contact layer 200 The contact layer is applied and does not serve to couple out electromagnetic radiation. 200 advantageously in the area of ​​the optoelectronic semiconductor chip 900 The generated radiation has a high reflection coefficient.

[0060] On the contact layer 200 is a first semiconductor material 902 arranged. The first semiconductor material 902 One example is a p-doped gallium nitride (GaN). The first semiconductor material 902 is an active zone 904 arranged. The active zone 904 consists, for example, of a material made of In x Ga (1–x) N-type semiconductor, with 0 ≤ x ≤ 1, and contains a single quantum well. On the active region 904 is a second semiconductor material 906 arranged. The second semiconductor material 906 The second semiconductor material is doped with a dopant that has a different polarity than the dopant of the first semiconductor material. 906 For example, an n-doped GaN.

[0061] The second semiconductor material 906 indicates one of the active zones 904 The opposite side has a roughened surface. This is located in the active zone.904 The generated electromagnetic radiation is coupled out of the semiconductor layer sequence via the roughened surface. The semiconductor layer sequence comprises the first semiconductor material. 902 , the active zone 904 and the second semiconductor material 906 The roughened surface allows for particularly efficient extraction of the radiation.

[0062] The roughened surface and the side faces of the semiconductor layer sequence are covered by a passivation layer. 908 They are covered and thus protected from environmental influences. The passivation layer 908 It can consist of the same or similar materials as the passivation layer. 208 in the embodiments described above.

[0063] To obtain the second semiconductor material 906 To make electrical contact, the passivation layer 908 on a radiation coupling side 910opened. There is contact material in the opening. 912 introduced. On the contact material 912 and partly on the passivation layer 908 is a conductive connection 914 applied. When selecting materials, low contact resistance is always a priority, and in the case of the contact material... 912 Attention is paid to high reflectivity, whereby, for example, the materials already described in connection with the other embodiments can be used.

[0064] The contact material 912 is through the conductive connection 914 completely covered, so that they pass through this and the passivation layer 908 is encapsulated. This makes the contact material 912 protected from degradation caused by external influences, such as oxidation.

[0065] As already described in the previous section, the function of the contact material is 912 , to establish an electrical contact with the semiconductor layer sequence, while the conductive connection 914 especially for current distribution on the radiation coupling side 910 serves this purpose. Accordingly, both structures can be optimized accordingly. This will be demonstrated using the following example: Fig. 10 and the Fig. 11 shown.

[0066] Fig. Figure 10 shows a schematic representation of a top view of the optoelectronic semiconductor chip 900 The design of the conductive connection is important in this context. 914 on the radiation output side 910 shown. The conductive connection 914 is electrically connected to a contact terminal 1000 connected. The contact connection 1000 It is used to connect the optoelectronic semiconductor chip. 900with a power supply. For example, it is designed as a bond pad that can be connected to a bond wire.

[0067] The conductive connection 914 runs along the radiation output side 910 , whereby care is taken to minimize the shading of the radiation. Since the function of the conductive connection is particularly in the distribution of a signal via the contact connection 1000 When dealing with the supplied electric current, the aim is to maintain the highest possible constant conductivity across the entire spatial extent of the conductive connection.

[0068] Fig. Figure 11 shows a schematic representation of a top view of the optoelectronic semiconductor chip 900 The design of the contact material is important in this context. 912 on the radiation output side 910 The function of the contact material is shown. 912consists in particular of a homogeneous current imprint via the radiation coupling side. 910 According to the potential drop from the contact point 100 along the conductive connection 914 and the contact material 912 indicates the contact material 912 Therefore, a better connection is achieved, for example through the larger contact area, the further a region of the contact material is. 912 from the contact connection 1000 is located far away. This can be achieved, for example, as shown, by making the contact material 912 from the contact connection 1000 This results in a constant current input and thus a homogeneous light pattern on the radiation output side. 910 achieved. EXAMPLES OF THE MANUFACTURING PROCESS

[0069] Fig.Figure 12 shows a schematic representation of a method for manufacturing an optoelectronic semiconductor chip. The method can be part of a manufacturing process that includes known process steps for manufacturing a semiconductor chip.

[0070] In a first procedural step 1200 A semiconductor layer sequence is provided, which has a radiation extraction side. The semiconductor layer sequence can be produced by epitaxial growth. For example, it may have been produced as part of a thin-film process.

[0071] In a second procedural step 1202 A transparent intermediate layer is applied to the radiation output side. This intermediate layer can be applied using a known method, such as sputtering or CVD. The intermediate layer can be a dielectric or a conductive material, such as ITO.

[0072] In a third process step, the intermediate layer is added. 1204 A recess is opened. In a fourth process step, material is placed in the recess. 1206 A contact material is introduced. These process steps can include, for example, steps such as photolithography, local opening of the transparent intermediate layer, deposition of the contact material, etc.

[0073] In a fifth process step, a conductive compound is applied to the contact material.

[0074] The process can be carried out using known process steps. In one embodiment, for example, after wafer bonding and optional mesa etching, an intermediate layer in the form of a passivation can be deposited on the wafer. In a photolithography step, the passivation is opened, and a metallic alloy is introduced into the opening as a contact material. By removing the previously used photoresist, the contact material can be lifted from outside the opening. The conductive compound can then be deposited and structured using a further photolithography technique. Advantageously, a contact terminal, such as a bond pad, is located on the passivation, so that no direct current flow from the contact terminal via the radiation coupling side into the semiconductor layer sequence occurs. Absorption at the contact terminal is thus kept to a minimum.

[0075] In one variant of this embodiment, the same material is used for both the contact material and the conductive connection. In this case, the photoresist can be removed immediately after opening the passivation in a first photostep, and both the contact material and the conductive connection can be deposited in a single process step in a further photostep.

[0076] In another embodiment, contact points are applied to the radiation extraction side as contact material. Additionally, a contact terminal can already be applied to the radiation extraction side. A transparent conductive layer is then deposited. If the contact terminal is already present, this layer is opened, at least in the central region of the contact terminal. Otherwise, a contact terminal is applied to the transparent conductive layer. To prevent direct current flow beneath the contact terminal and the contact points to the support side of the semiconductor layer sequence opposite the radiation extraction side, the support side is electrically insulated in areas directly beneath the contact material.

[0077] It is possible to first apply a passivation layer and then a transparent conductive layer to the radiation coupling side.

[0078] It is possible that the contact material is structured directly on the radiation extraction side. Alternatively, a transparent intermediate layer, such as a passivation layer and / or a conductive layer, could first be applied, followed by the creation of a recess into which the contact material is inserted. FINAL FINDINGS

[0079] The optoelectronic semiconductor chip and the method for manufacturing an optoelectronic semiconductor chip have been described using several exemplary embodiments to illustrate the underlying concept. These exemplary embodiments are not limited to specific combinations of features. Even if some features and configurations are described only in connection with a particular embodiment or individual embodiments, they can each be combined with other features from other embodiments. It is also possible to omit or add individual features or special configurations to the exemplary embodiments, provided that the general technical teaching is still realized.

[0080] Even though the steps of the process for manufacturing an optoelectronic semiconductor chip are described in a specific order, it is self-evident that each of the processes described in this disclosure can be carried out in any other sensible order, whereby process steps can also be omitted or added, provided that the basic idea of ​​the described technical teaching is not deviated from. LITERATURE

[0081] This document cites the following publications: [1] I. Schnitzer et al.: Appl. Phys. Lett. 63 (16), pp. 2174–2176. October 18, 1993; [2] EP 0 905 797 A2 and [3] WO 02 / 13281. Reference symbol list 100 Optoelectronic Semiconductor Chips 102 Radiation coupling side 104 Contact connection 106 Conductive connection 200 contact layer 202 Separation layer 204 Semiconductor layer sequence 206 Impoverishment zone 208 Passivation layer 210 Contact point 300 bonding layer 400 Optoelectronic semiconductor chips 500 Transparent Conductor Layer 900 Optoelectronic semiconductor chips 902 First semiconductor material 904 Active Zone 906 Second Semiconductor Material 908 Passivation layer 910 Radiation coupling side 912 Contact material 914 Conductive connection 1000 contact points QUOTES INCLUDED IN THE DESCRIPTION

[0082] 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

[0083] EP 0905797 A2

[0081] WO 02 / 13281

[0081] Cited non-patent literature

[0084] I. Schnitzer et al.: Appl. Phys. Lett. 63 (16), pp. 2174–2176. October 18, 1993

[0081]

Claims

[1] Optoelectronic semiconductor chip with: – a radiation output coupling side ( 102 , 910 ); – a contact connection ( 104 , 1000 ); – one on the radiation output side ( 102 , 910 ) applied contact material ( 210 , 912 ) and – one of the contact material ( 210 , 912 ) applied and connected to the contact point ( 104 , 1000 ) connected conductive connection ( 106 , 500 , 914 ). [2] Optoelectronic semiconductor chip according to claim 1, wherein in projection onto the radiation extraction side ( 102 , 910 ) an area of ​​the contact material ( 210 , 912 ) is smaller than an area of ​​the conductive connection ( 106 , 500 , 914 ). [3] Optoelectronic semiconductor chip according to one of the preceding claims, wherein the conductive connection ( 106 , 500 , 914 ) includes a cable tray structure. [4] Optoelectronic semiconductor chip according to one of the preceding claims, wherein the conductive connection ( 106 , 500 , 914 ) includes a transparent conduction layer. [5] Optoelectronic semiconductor chip according to one of the preceding claims, wherein the conduction layer ( 106 , 500 , 914 ) comprises a transparent metal oxide. [6] Optoelectronic semiconductor chip according to claim 5, wherein between the conductive connection ( 106 , 500 , 914 ) and the radiation coupling side ( 102 , 910 ) at least in sections a dielectric is provided. [7] Optoelectronic semiconductor chip according to one of the preceding claims, wherein the contact material ( 210 , 912 ) such on the radiation coupling side ( 102 , 910 ) is distributed so that the current density across the semiconductor chip is as homogeneous as possible. [8] Optoelectronic semiconductor chip according to one of the preceding claims, wherein the contact material ( 210 , 912 ) has a large number of separate contact areas, especially contact points [9] Optoelectronic semiconductor chip according to claim 8, wherein the contact points are located on the radiation extraction side ( 102 , 910 are unevenly distributed. [10] Optoelectronic semiconductor chip according to claim 8, wherein the contact points have different sizes. [11] Method for manufacturing an optoelectronic semiconductor chip, comprising: – Providing a semiconductor layer sequence with a radiation extraction side ( 102 , 910 ); – Application of a contact material ( 210 , 912 ) on the radiation output side ( 102 , 910 ); – Applying a conductive connection ( 106 , 914 ) on the contact material ( 210 , 912 ). [12] Method according to claim 11 wherein the application of a contact material ( 210 , 912 ) on the radiation output side ( 102 , 910 ) includes: – Application of a transparent intermediate layer ( 208 , 500 , 908 ) on the radiation output side ( 102 , 910 ) – Opening a recess in the intermediate layer ( 208 , 500 , 908 ); – Insertion of the contact material ( 210 , 912 ) into the recess. [13] Method according to claim 12, comprising: – Applying a contact connection ( 104 , 1000 ) on the intermediate layer; – Providing a conductive connection that connects the contact terminal ( 104 , 1000 ) with the contact material ( 104 , 1000 ) connects. [14] Method according to one of claims 12 or 13, wherein the intermediate layer ( 208 , 500 , 908 ) is a dielectric. [15] Method according to one of claims 12 or 13, wherein the intermediate layer ( 208 , 500 , 908 ) is a conductor layer. [16] Method according to claim 15, comprising: – Applying another transparent conductive layer to the contact material ( 104 , 1000 ).

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