Multiple applications of aluminum nitride

Abstract

The invention relates to the use of aluminum nitride (AlN) for optoelectronic components and a device for coating these with AlN, wherein a layer, in particular an AlN layer (5), is applied to a substrate (1) by means of a method known from DE 10 2013 112 785 B3, wherein AlN or an AlN layer (5) is specifically used to encapsulate OLEDs or OLED layers (2), or wherein alternatively or additionally, AlN or an AlN layer (5) is used as a waveguide layer (6) for optical components for guiding optical signals and in particular in a transistor to control a gate contact of the transistor, or alternatively or additionally, that AlN is also used as a replacement for conventional gate oxides. In this context, the invention comprises a device for depositing AlN or AlN.an AIN layer (5) on a substrate (1) using two plasma sources at a maximum temperature of 80°C.

Description

[0001] The invention relates to the use of aluminum nitride (AlN) as a coating layer in processes for manufacturing optoelectronic components, in particular to protect organic layers or substrates, such as OLEDs, silicon carbide (SiC), or diamond, from harmful environmental influences such as moisture and oxygen. AlN is used as a multifunctional material that combines both protective and functional properties, such as the ability to serve as a waveguide for integrated photonics, as an insulating layer, as a replacement for gate oxides, or for dissipating waste heat.

[0002] In the prior art, the protection of sensitive organic layers is usually achieved by glass covers or coatings, or by sealing with polymers or films, which are sealed at the edges with resins. Increasingly, protective layers are also being applied using coating processes. However, these approaches have limitations, such as the restriction to small coating areas and the high temperatures required for conventional coating processes. This can lead to undesirable thermal stresses on the sensitive materials, which can impair the service life and functionality of the components. Furthermore, prior art documents WO 2014 / 163773 A1, US 2017 / 0018738 A1, DE 102011084276 B4, and WO 2020 / 002277 A1 are known, each describing different methods and materials for encapsulating or protecting organic electronic components.

[0003] The object of the present invention was to provide measures by which the aforementioned disadvantages can be overcome. In particular, it should be possible to carry out large-area coatings at low temperatures in order to protect sensitive substrates while simultaneously ensuring the versatility of the coating layer with regard to optoelectronic applications. The invention aims to provide robust and efficient measures for the production of durable and high-performance optoelectronic components.

[0004] This problem is solved by uses, methods and devices according to the claims.

[0005] According to the invention, aluminum nitride (AlN) is used to coat organic light-emitting diodes (OLEDs), wherein AlN is deposited onto the OLED layer by a process with two plasma sources as described in document DE 10 2013 112 785 B3 at a maximum temperature of 80 °C to protect it from air and moisture. The apparent advantage of this is that the low deposition temperature prevents thermal stress on sensitive OLED layers, thereby significantly improving the lifespan and performance of the OLEDs.

[0006] Furthermore, the AIN layer may be designed to have a thickness of 1 nm to 150 µm to ensure an effective barrier effect while minimizing the impairment of the optical properties of the OLED.

[0007] In particular, it can be advantageous to apply a polymer layer between the AIN layer and the OLED layer to improve the flexibility of the overall structure or the adhesion of AIN to the OLED layer. In this context, it may also be possible to grow a polymer layer onto the AIN.

[0008] In one specific implementation, the polymer layer between the AIN layer and the OLED layer may comprise a fluoropolymer with exceptionally low water vapor permeability, thus maximizing the OLED's lifespan. The advantage lies in the significant reduction of moisture damage, which increases the reliability of the OLEDs.

[0009] Another advantageous design involves applying the AIN layer in multiple successive layers, each with a thickness of 1 nm to 20 µm, to prevent cracks or defects in the protective layer. This results in a more uniform and stable protective layer, thereby improving the protective effect and mechanical integrity of the OLEDs.

[0010] According to further training, it is possible to apply an additional layer of sapphire (Al2O3), silicon dioxide (SiO2), diamond, or silicon carbide (SiC) to the AIN layer to achieve further protective or functional properties. This expands the functional properties of the layers and offers better protection against physical and chemical influences.

[0011] In general terms, silicon dioxide (SiO2) would be replaced by SiO xInterchangeable, since both stoichiometric and non-stoichiometric silicon dioxide can be used depending on the specific application. The same applies analogously to silicon nitride (Si3N4), whereby silicon nitride can be replaced in any case by Si x N y This depends on whether stoichiometric or non-stoichiometric silicon nitride can be applied according to an applicable method. This applies to the entire following discussion.

[0012] In this context, it may be advantageous for the two plasma sources to be configured so that the plasma beams overlap in order to enable uniform deposition of the AIN layer on complexly shaped OLED surfaces.

[0013] According to the invention, the use of aluminum nitride (AlN), sapphire (Al₂O₃), silicon dioxide (SiO₂), diamond, or silicon carbide (SiC) as a waveguide layer for optical components for guiding optical signals, and in particular in a transistor to control a gate contact of the transistor, is also possible. The advantage is that the use of waveguides increases the circuit density and improves the efficiency of optoelectronic systems, opening up new design possibilities for integrated circuits.

[0014] Furthermore, it can be advantageous to use the waveguide layer in an optoelectronic mixing circuit that integrates both optical and electronic components to reduce the number of components and improve energy efficiency. The waveguide layer is used to reduce switching times in power electronics components. The advantage lies in minimizing energy losses and improving signal processing speed, which is particularly important in high-frequency applications. This allows the circuit to be packed more densely with conductors, since the gate can be controlled with light.

[0015] The waveguide layer can make the structure somewhat more complex, as waveguide tracks must be included in addition to the metal tracks.

[0016] Furthermore, the waveguide layer can be embedded in a cladding layer, particularly fully encased, to improve optical signal guidance and reduce scattering. The advantage is increased precision in optical signal transmission and a reduction in energy losses, thus improving the efficiency of optical systems. In this context, it can also be provided that both the surface and the side faces of the waveguide layer are embedded in or coated with the cladding layer.

[0017] In a specific design, the cladding layer can be made of amorphous silicon dioxide (SiO2) to ensure low optical losses. The advantage lies in the significant reduction of signal loss, thereby increasing the performance and reliability of optical components.

[0018] According to a further advantageous development, the waveguide layer can be used in combination with other semiconductor layers such as gallium nitride (GaN), silicon carbide (SiC), silicon germanium (SiGe), or silicon (Si) to achieve improved conductivity, integration, and broader applicability across a wide spectral range from UV to infrared. The advantage lies in expanding the spectral application possibilities and optimizing the material properties for specific optoelectronic applications.

[0019] According to further training, it is possible to optimize the waveguide layer through a thermal post-treatment process using a laser in order to improve the crystal structure and minimize optical losses.

[0020] According to the applicability of the method based on DE 10 2013 112 785 B3, AIN can also serve as or be applied as a gate passivation layer, thus replacing the classic SiO x or you x N y as a replacement for gate oxides. According to further training, Al2O3, SiC, or diamond can also be used, especially as a replacement for the gate oxide in a transistor. Due to the so-called remote plasma, the surface of a transistor is not damaged by the applicable method from DE 10 2013 112 785 B3, so that Al2O3 can be used as a gate passivation layer.

[0021] The invention further relates to a method for coating OLEDs with aluminium nitride (AIN), comprising: the application of an AIN layer to the OLED layer or to an organic and / or inorganic coating on an OLED layer by means of two plasma sources, wherein the temperature during deposition is a maximum of 80 °C in order to avoid thermal impairment of the OLED layer.

[0022] It can be advantageous to apply an additional polymer layer between the OLED layer and the AIN layer to improve the mechanical flexibility of the layers. The benefit lies in the thermal protection of the OLED layer, which improves the lifespan and efficiency of the OLEDs. In particular, this allows for the simple and effective production of flexible OLED devices suitable for flexible displays and wearables.

[0023] Furthermore, it may be possible to apply an additional layer of silicon dioxide (SiO2), sapphire (Al2O3), diamond, or silicon carbide (SiC) after the deposition of the AIN layer to enhance the protective effect. The advantage lies in the improved chemical and mechanical stability of the protective layer, which increases the durability and reliability of the coated components.

[0024] Furthermore, it may be advantageous to move the substrate back and forth below plasma sources or vice versa to achieve a uniform layer thickness across the entire OLED surface.

[0025] The invention also relates to a method for producing an optical waveguide made of aluminum nitride (AlN), comprising: the deposition of an AlN layer onto a substrate using two plasma sources, wherein the AlN layer has a thickness of 50 to 1500 nm and serves to transmit optical signals. The advantage lies in the precise control of the layer thickness, which leads to improved signal transmission and lower losses.

[0026] According to a further advantageous development, the AIN layer can be applied to a flexible substrate to create a flexible waveguide structure that can be used in flexible optical devices. The advantage lies in the possibility of developing innovative flexible optical systems that can be used in portable devices and flexible displays.

[0027] In particular, it can be advantageous to embed the AIN layer in a cladding layer made of a material with a low refractive index to achieve high mode configuration. The benefit lies in improved signal transmission and minimized stray losses, which increases the efficiency of optical waveguides.

[0028] Furthermore, the AIN layer can be used in combination with a silicon (Si), silicon carbide (SiC), gallium nitride (GaN), diamond, or silicon germanium (SiGe) layer in the circuit to create a hybrid structure that combines both optical and electronic switching properties. The advantage is increased integration of optical and electronic functions, resulting in more versatile and powerful systems.

[0029] In this context, it may again be intended that AIN serves as a gate passivation layer and thus replaces the classic SiO₂.x or you x N y as a gate oxide. According to further research, Al2O3, SiC or diamond can also be used, especially as a replacement for the gate oxide in a transistor.

[0030] According to the invention, it is provided that the deposition of the AIN layer is carried out using several plasma sources, wherein the AIN layer is deposited using a first and a second plasma source according to the method from DE 10 2013 112 785 B3, wherein a third plasma source generates a homogeneous plasma field for pretreating a substrate surface of the substrate or an OLED surface of an OLED and for increasing the surface energy of the substrate or the OLED surface, wherein the intensity of the first and the second plasma source and the distance to the substrate or to the OLED are adjusted so that a uniform layer formation is achieved at a temperature of the substrate surface of the substrate or the OLED surface of a maximum of 80 °C.

[0031] According to the invention, it is further provided that the first plasma source is operated with a variable frequency in order to precisely control the surface modification of the substrate or the OLED surface and to optimize the adhesion of the AIN layer.

[0032] In one particular implementation, a polymer layer can be applied between the substrate or OLED layer and the AIN layer to improve the mechanical flexibility of the layers. This polymer layer is a fluorinated polymer with particularly low water vapor permeability, further optimizing the protection of the substrate or OLED layer. The advantage lies in the significant increase in moisture resistance, thereby extending the lifespan of the substrate or OLEDs.

[0033] In this context, it may also be possible to grow a polymer layer onto the AIN layer.

[0034] The invention also relates to a device for coating OLEDs with aluminum nitride (AlN), comprising: a process chamber for holding OLED substrates, at least two plasma sources for deposition of AlN at temperatures of up to 80 °C, and a control unit for regulating the plasma conditions of the at least two plasma sources and the substrate temperature. The advantage of this device lies in the possibility of coating sensitive OLED substrates precisely and with minimal temperature stress, thereby improving the quality and lifespan of the OLED layers.

[0035] The control unit is typically designed to dynamically adjust the frequency and intensity of the plasma sources in order to regulate the deposition rate and layer thickness of the AIN layer in real time.

[0036] Furthermore, the device may include a heating element that enables uniform heating of the OLED substrates to temperatures below 80 °C, thus ensuring the thermal stability of the OLED layer. The advantage lies in the prevention of thermal degradation, thereby preserving the mechanical and optical properties of the OLEDs.

[0037] In this context, it may be provided that the heating device is designed to adjust the temperature for different substrate materials in order to ensure optimal adhesion of the AIN layer to various organic and / or inorganic materials.

[0038] In particular, it can be advantageous if the device includes a material source for applying a polymer layer between the OLED and AIN layers. The advantage lies in the possibility of applying additional functional layers, which increases the flexibility and protective effect of the overall layer structure.

[0039] It can be advantageous if the plasma sources are variably positionable or if the plasma beam of the respective plasma source is variably adjustable in order to adapt the deposition angles to the geometry of the OLED substrates and thus optimize layer uniformity. Alternatively or additionally, it can be considerably more beneficial if the substrate can be moved back and forth beneath the plasma and / or material sources, or vice versa, in order to ensure uniform layer formation in an improved manner.

[0040] The invention also relates to a device for producing an optical waveguide made of aluminum nitride (AlN), comprising: a process chamber for depositing AlN on a substrate, a control unit for adjusting the deposition parameters, including the plasma intensity and the pressure in the process chamber, and a cladding device for applying a layer with a low refractive index around the AlN layer. The advantage lies in the precise control of the process parameters, which enables the production of high-quality waveguides with low optical losses.

[0041] According to a further advantageous design, the cladding device can include a temperature-controlled chamber for depositing the cladding layer from a material with a low refractive index, in order to ensure homogeneous cladding of the AIN layer under optimal conditions. The advantage lies in the improved optical performance and the possibility of creating customized waveguide structures.

[0042] Furthermore, it can be advantageous for the process chamber for the deposition of the AIN layer to include a vacuum pump capable of reducing the pressure in the chamber to a value between 0.1 mbar and 0.0000001 mbar (corresponding to 0.1 hPa to 0.0000001 hPa) in order to achieve high purity of the deposited layer. The advantage lies in the improved purity and homogeneity of the deposited layers, thereby increasing the functionality of the components.

[0043] Furthermore, the chamber can be equipped with an optical monitoring unit to monitor and adjust the thickness of the AIN layer in real time. This optical monitoring unit comprises an interferometry or ellipsometry unit, particularly a reflectometry unit, to monitor the thickness of the AIN layer during deposition in a range of 50 nm to 1.5 µm. The advantage lies in continuous quality control during the coating process, which improves the precision and efficiency of the manufacturing process.

[0044] To better understand the invention, it is explained in more detail with reference to the following figures.

[0045] They each show, in a highly simplified, schematic representation: Fig. 1 one possible embodiment of the use of aluminium nitride (AlN) as a top layer for an organic layer; Fig. 2 a possible embodiment of the use of aluminium nitride (AlN) as a waveguide for integrated photonics;

[0046] It should be noted at the outset that in the differently described embodiments, identical parts can be provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these positional designations must be applied analogously to the new position if the position changes.

[0047] In the Fig. Figure 1 shows a possible embodiment of using aluminum nitride (AlN) as a top layer for an organic layer, particularly for an OLED, in a highly simplified, schematic representation. This can be used primarily for the manufacture of optoelectronic components or parts thereof. For example, in the manufacture of an optoelectronic component or parts thereof, a substrate 1 and / or a special OLED substrate can be used, on which an OLED or an OLED layer 2 can be applied. In any case, it can be advantageous if the OLED layer 2 is coated, encapsulated, or encapsulated with a first layer 3 using the method known from DE102013112785B3. It can also be provided that the first layer 3 is in turn coated, encapsulated, or encapsulated with a second layer 4.

[0048] In particular, it may be intended that the first layer 3 is an AIN layer 5. However, it is conceivable that the first layer 3 consists of a material from a first material list comprising AIN, Al2O3, Si x N y , SiO x The first layer is selected from SiC, TiN, CuN, AION, and polymer or plastic polymer. It can also be specified that the second layer 4 is also selected from a material in the first material list. It can also be advantageous if the OLED layer 2 is coated, encapsulated, or coated with an alternating sequence of layers from the first layer 3 and the second layer 4.

[0049] In Fig. Figure 2 shows a possible embodiment of the use of aluminum nitride (AlN) as a waveguide or as waveguide layer 6 for integrated photonics in a highly simplified, schematic representation. It can be advantageous to use the waveguide layer 6 in an optoelectronic mixing circuit that integrates both optical and electronic components to reduce the number of components and improve energy efficiency. Furthermore, the waveguide layer 6 can be used to reduce switching times in power electronics components, particularly in applications requiring fast signal processing.

[0050] In any case, a substrate 1 or a substrate layer can again be provided as a support material, wherein a waveguide layer 6, or in particular an AIN layer 5, is applied as waveguide layer 6. The waveguide layer 6 is not necessarily limited to the use of AIN, but the waveguide layer 6 can also be made of a material selected from a second material list comprising AIN, Al2O3, Si3N4, SiO2, diamond, Si, Ge, SiGe, lithium nobiate and 3C-SiC.

[0051] As from Fig.As can be seen in Figure 2, the waveguide layer 6 does not necessarily have to be applied directly to the substrate layer 1, which, incidentally, can be selected from a third material list comprising sapphire, Si, SiC, SiG, GaN, diamond, glass, polymer, and metal. Instead, the waveguide layer 6 can also be embedded in a cladding layer 7. This cladding layer can be made of a material selected from a fourth material list comprising Si3N4, SiO2, SiC, and Ge.

[0052] The exemplary embodiments show possible embodiment variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiment variants, but rather various combinations of the individual embodiment variants are also possible and this possibility of variation lies within the skill of the person skilled in this technical field due to the teaching on technical action by the present invention.

[0053] The scope of protection is defined by the claims. However, the description and drawings must be consulted for the interpretation of the claims. Individual features or combinations of features from the different embodiments shown and described can, in themselves, represent independent inventive solutions. The problem underlying these independent inventive solutions can be found in the description.

[0054] All references to value ranges in this description are to be understood as encompassing any and all sub-ranges thereof, e.g., the reference 1 to 10 is to be understood as including all sub-ranges, starting from the lower limit 1 and the upper limit 10, i.e., all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g., 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0055] Finally, for the sake of clarity, it should be noted that, for a better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced in size. Reference numeral list 1 substrate 2 OLED layers 3 First shift 4 Second shift 5 AIN layer 6 Waveguide layer 7. Mantle layer

Claims

[1] Use of aluminium nitride for coating organic light-emitting diodes or OLEDs, wherein aluminium nitride is deposited as an AIN layer (5) onto an OLED layer (2) by a process with two plasma sources at a temperature of at most 80 °C to protect it from air and moisture, wherein the deposition of the AIN layer (5) is carried out by means of a first and a second plasma source, characterized by , - that a third plasma source generates a homogeneous plasma field for pretreating an OLED surface, wherein the intensity of the first and second plasma sources and the distance to the OLED are adjusted to achieve uniform layer formation at a temperature of the OLED surface of a maximum of 80 °C and - that the first plasma source is operated at a variable frequency to precisely control the surface modification of the OLED surface and to optimize the adhesion of the AIN layer (5). [2] Use according to claim 1, characterized by , that the AIN layer (5) has a thickness of 1 nm to 150 µm to ensure an effective barrier effect while minimizing impairment of the optical properties of the OLED. [3] Use according to any one of the preceding claims, characterized by , that a polymer layer (3) is applied between the AIN layer (5) and the OLED layer (2) to improve the flexibility of the overall structure or the adhesion of aluminium nitride to the OLED layer (2). [4] Use according to claim 3, characterized by , that the polymer layer (3) between the AIN layer (5) and the OLED layer (2) comprises a fluoropolymer that has a particularly low water vapor permeability in order to maximize the lifetime of the OLED. [5] Use according to any one of the preceding claims, characterized by, that the AIN layer (5) is applied in several successive layers, each layer having a thickness of 1 nm to 20 µm to avoid cracks or defects in the protective layer. [6] Use according to any one of the preceding claims, characterized by , that an additional layer (4) of sapphire, silicon dioxide, diamond or silicon carbide is applied to the AIN layer (5) to achieve further protective or functional properties. [7] Method for coating OLEDs with aluminium nitride, comprising: depositing an AIN layer (5) onto an OLED layer (2) or onto an organic and / or inorganic coating on an OLED layer (2) using a first plasma source and a second plasma source, wherein the temperature during deposition is a maximum of 80 °C to avoid thermal damage to the OLED layer (2), characterized by , - that an OLED surface is pretreated using a third plasma source, wherein the intensity of the first and second plasma sources and the distance to the OLED are adjusted so that a uniform layer formation is achieved at a temperature of the OLED surface of a maximum of 80 °C, and - that the first plasma source is operated at a variable frequency to precisely control the surface modification of the OLED surface and to optimize the adhesion of the AIN layer (5). [8] Method according to claim 7, characterized by , that an additional polymer layer (3) is applied between the OLED layer (2) and the AIN layer (5) to improve the mechanical flexibility of the layers. [9] Method according to claim 7 or 8, characterized by , that after the deposition of the AIN layer (5) a further layer (4) of silicon dioxide, sapphire, diamond or silicon carbide is applied to enhance the protective effect. [10] Device for coating OLEDs with aluminium nitride as an AIN layer (5), comprising: a process chamber for receiving OLED substrates, at least one first plasma source and a second plasma source for depositing aluminium nitride at temperatures of at most 80 °C, and a control unit for controlling plasma conditions of the at least first and second plasma source and the substrate temperature, characterized by , - that the device comprises a third plasma source for generating a homogeneous plasma field for pretreating an OLED surface, wherein the intensity of the first and second plasma sources and the distance to the OLED are adjustable so that uniform layer formation can be achieved at a temperature of the OLED surface of a maximum of 80 °C, and - that the first plasma source can be operated with a variable frequency to precisely control the surface modification of the OLED surface and to optimize the adhesion of the AIN layer (5). [11] Device according to claim 10, characterized by , that the device includes a heating device which enables uniform heating of the OLED substrates to temperatures below 80 °C in order to ensure the thermal stability of an OLED layer (2) of the OLEDs. [12] Device according to claim 11, characterized by , that the device comprises a material source for applying a polymer layer (3) between the OLED layer (2) and the AIN layer (5).

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