Laser-excited arc discharge for forming a layer comprising an electrically conductive ceramic, use thereof and method therefor

Abstract

Various embodiments relate to a laser-excited arc discharge (214) for forming a layer by means of a target (112) which is exposed to the arc discharge (214) and comprises or consists of a ceramic, wherein the layer and / or the ceramic are electrically conductive.

Description

[0001] Description

[0002] Laser-stimulated arc discharge for forming a layer which has an electrically conductive ceramic, use thereof and method for doing so.

[0003] Various embodiments relate to a laser-excited arc discharge for forming a layer which has an electrically conductive ceramic, a use thereof and a method for doing so.

[0004] In general, a substrate (e.g., a workpiece) can be coated to modify its chemical and / or physical properties. This coating process can be carried out in a vacuum, where one or more layers are deposited onto the substrate using a vapor deposition (e.g., physical) process. However, this often presents challenges that make it difficult to meet the high demands placed on the vapor deposition and the resulting coating. These demands include industrial scalability and the properties of the coating. Industrial scalability, in particular, frequently poses numerous obstacles, as laboratory concepts cannot always be easily scaled up without compromising on performance and / or cost-effectiveness.

[0005] This applies in particular to the material class of so-called transparent, electrically conductive oxides (also known as TCOs), which are used as key components in optoelectronic devices, e.g., in flat panel displays or photovoltaics, and therefore have high economic value. Among other things, a transparent thin-film electrode for the optoelectronic device can be produced from TCOs. In this context, there is a general aim to achieve the highest possible optical transparency and electrical conductivity of the TCO layer.

[0006] Against this background and contrary to established opinion, various embodiments have revealed that arc evaporation, a type of physical vapor deposition (PVD), facilitates the fulfillment of high requirements for a TCO layer. In this context, it has been recognized that laser-excited arc discharge favors the use of a ceramic target to form one or more TCO layers that meet stringent requirements. It has been clearly demonstrated that laser-excited arc discharge (also known as laser arc) promotes the cost-effective deposition of TCO (transparent, electrically conductive oxide), which can be scaled up to a large coating area with minimal compromise in terms of requirements and / or cost-efficiency, particularly due to a high degree of ionization and low particle energies, thus facilitating industrial scalability.What has been described for TCO applies analogously to any other electrically conductive and / or transparent ceramic.

[0007] Exciting the arc discharge with a laser (also known as laser excitation) compensates for the effects of the ceramic properties of the target. Among other things, laser excitation ensures that the arc discharge ablates and heats the target uniformly.

[0008] According to an exemplary implementation, a ceramic target material, with a possibly adapted discharge regime, is vaporized using a laser arc. The laser arc, as a pulsed vaporization process, allows the position of the arc discharge on the target (also referred to as the arc base or discharge point), where the target is vaporized (also referred to as arc vaporization), to be influenced (e.g., controlled). This facilitates scalability. Furthermore, the coating process does not necessarily require the arc discharge base to move independently, which reduces the risk of excessively slow arc base movement and thus the risk of pitting on the target. Several examples relating to the concepts described herein and illustrated in the figures are described below.

[0009] Example 1 is set up according to one of the attached claims and / or is the use of a laser-excited arc discharge to form a (e.g., electrically conductive and / or transparent) layer, which preferably comprises or consists of a (e.g., electrically conductive and / or transparent) ceramic (e.g., an oxide) (then also referred to as ceramic), by means of a (e.g., ceramic and / or oxide) target which is exposed to the arc discharge (into which the arc discharge leads) and / or which comprises the (e.g., doped) ceramic.

[0010] Example 2 (e.g., using) is set up according to Example 1, wherein the excitation of the arc discharge is carried out by means of a laser, which is preferably set up to direct a (e.g., pulsed) laser beam onto the target.

[0011] Example 3 (e.g., a process) is set up according to Example 1 or 2, wherein the formation of the layer, which has or consists of a transparent and / or electrically conductive ceramic, is carried out by means of a material stream emitted from the target, which is generated by means of the arc discharge.

[0012] Example 4 is a method comprising: exciting an arc discharge by means of a laser exposed to a (e.g. ceramic and / or oxide) target which, for example, has a (e.g. electrically conductive) ceramic; forming a layer which preferably has or consists of the (e.g. electrically conductive) ceramic (e.g. oxide) and / or is electrically conductive, by means of the arc discharge.

[0013] Example 5 (e.g., a use and / or method) is set up according to one of Examples 1 to 4, wherein the target is exposed to a vacuum (e.g., vacuum pressure) and / or is arranged in a vacuum chamber.

[0014] Example 6 (e.g., a use and / or method) is set up according to one of Examples 1 to 5, wherein the arc discharge is supplied by means of an electrical pulse and / or a generator (e.g., pulse current generator).

[0015] Example 7 (e.g., a use and / or method) is set up according to one of Examples 1 to 6, wherein the target is rotated about an axis of rotation and / or is tubular.

[0016] Example 8 (e.g., a use and / or procedure) is set up according to one of Examples 1 to 7, wherein the excitation of the arc discharge occurs several times in succession and / or is spatially shifted according to a target spatial distribution (e.g., target pattern), with which the target of the arc discharge is set and / or with which different areas of the target are represented at which the arc discharge is to enter the target.

[0017] Example 9 (e.g., a use and / or method) is set up according to any one of Examples 1 to 8, wherein the ceramic and / or the target comprises a chemical compound of oxygen, preferably a chemical compound of a metal (e.g., aluminium, indium, titanium, niobium, zirconium, tin and / or zinc).

[0018] Example 10 (e.g., a use and / or method) is set up according to any one of Examples 1 to 9, wherein the ceramic and / or the target comprises a metal, preferably aluminium, indium, titanium, niobium, zirconium, tin and / or zinc.

[0019] Example 11 (e.g., a use and / or method) is set up according to one of Examples 1 to 10, wherein the target and / or the ceramic comprises or consists of an oxide semiconductor. Example 12 (e.g., a use and / or method) is set up according to one of Examples 1 to 11, wherein the layer is formed by means of a material stream emitted from the target, which is generated by the arc discharge and / or from which particles are removed by means of a filter (also referred to as filtering).

[0020] Example 13 (e.g., a use and / or method) is set up according to one of Examples 1 to 12, wherein the target and / or ceramic is doped, preferably with a metal (e.g., tin and / or zinc) and / or with an oxide.

[0021] Example 14 (e.g., a use and / or method) is set up according to one of Examples 1 to 13, wherein the target and the layer (e.g., at least temporarily) differ from each other in an electrical potential (also called a bias potential) applied to them. This promotes high layer quality. For example, the bias potential can be pulsed and / or linked to a time dependency with which the laser excitation of the arc discharge is carried out.

[0022] Example 15 (e.g., a use and / or method) is set up according to one of Examples 1 to 14, wherein a filter is arranged between the target and the layer, which is configured to filter out particles emitted by the target (e.g., to separate them from the material stream). The filter can be implemented, for example, by means of an electric and / or a magnetic field.

[0023] Example 16 (e.g., a use and / or method) is set up according to one of Examples 1 to 15, wherein the layer, the target and / or at least the ceramic is transparent (e.g., translucent) and / or electrically conductive.

[0024] Example 17 (e.g., a use and / or process) is set up according to one of Examples 1 to 16, wherein the layer, the target and / or at least the ceramic (e.g., its chemical compound) is substoichiometric.

[0025] Example 18 (e.g., a use and / or method) is set up according to one of Examples 1 to 17, wherein the arc discharge is terminated by a timer and / or current control. For example, the duration of the arc discharge can be a function of a (e.g., stored) time preset (also referred to as time-controlled) and / or limited by influencing (e.g., terminating) the electrical current supplied to the arc discharge according to the time preset. This can be achieved, for example, by means of a circuit that implements a clock and / or the time preset.

[0026] Example 19 (e.g., a use and / or method) is set up according to one of Examples 1 to 18, wherein the target and / or the arc discharge are exposed to a magnetic field. This promotes layer formation and / or makes it easier to influence the spatial path of the arc discharge.

[0027] Example 20 (e.g., a use and / or method) is set up according to one of Examples 1 to 19, wherein the layer provides an electrode (e.g., transparent and / or electrically conductive), preferably an electrode of an optoelectronic component, such as a screen (e.g.,

[0028] liquid crystal display and / or touchscreens), a (e.g. organic) light-emitting diode, a photovoltaic component (e.g. solar cell), etc.

[0029] Example 21 (e.g., a use and / or method) is set up according to one of Examples 1 to 20, wherein the target, layer, and / or ceramic has an electrical conductivity of more than 10 5 S / m (e.g. as 10 S / m, e.g. as 10 3 S / m), preferably as 10 2 S / m (e.g. as 10 1 S / m, e.g. as 1 S / m, e.g. as 10 S / m), further preferably as 10 2 S / m (e.g. as 10 3 S / m) and / or less than 10 7S / m (e.g. as 10 6 S / m, e.g. as 10 4 S / m). In the case of ITO as the target material, the target, layer, and / or ceramic can exhibit an electrical resistance lower than that of intrinsic ZnO and intrinsic indium oxide. The value of intrinsic ZnO can range from approximately 100 Ωm (e.g., 500 Ωm) to approximately 5000 Ωm (e.g., 1000 Ωm). For example, the electrical conductivity of ITO can be less than 10 4 Q'm, e.g. as 10 6 Q'm.

[0030] Example 22 is a method comprising: controlling one or more than one actuator to form a layer according to the use / method according to one of Examples 1 to 21.

[0031] Example 23 is a computer program that implements instructions which, when executed by one or more processors, are set up to cause the processor to perform the procedure according to Example 22.

[0032] Example 24 is a computer-readable medium that stores instructions which, when executed by a processor, are set up to cause the processor to perform the procedure according to Example 22.

[0033] Example 25 is a control device which has one or more processors configured to perform the procedure according to Example 22.

[0034] Example 26 is a vacuum arrangement comprising: a vacuum chamber, a coating device configured to excite an arc discharge in the vacuum chamber by means of a laser to which a target of the coating device is exposed, which has a (e.g. electrically conductive) ceramic; a substrate holder for holding a substrate in the vacuum chamber on which the formation of a layer, which preferably has or consists of the ceramic (e.g. oxide), takes place by means of the arc discharge; optionally the control device according to claim 25.

[0035] Example 27 (e.g., a use and / or method) is set up according to one of Examples 1 to 26, wherein the layer is formed on a (e.g., doped) semiconductor material (e.g., the substrate) and / or a substrate cell precursor.

[0036] Example 28 (e.g., a use and / or method) is set up according to one of Examples 1 to 27, wherein the layer and / or the ceramic (e.g., of the layer) is substoichiometric.

[0037] Example 29 (e.g., a use and / or process) is set up according to any of Examples 1 to 28, wherein the layer, target, and / or at least the ceramic contains at least oxygen, nitrogen, and / or carbon, e.g., a chemical compound containing or consisting of oxygen, nitrogen, and / or carbon.

[0038] Example 30 (e.g., a use and / or method) is set up according to one of Examples 1 to 29, wherein the layer, target and / or ceramic contains at least tin and / or indium.

[0039] Example 31 (e.g., a use and / or process) is set up according to one of Examples 1 to 30, wherein the target, layer, and / or ceramic has a transmittance of more than 25% (e.g., more than 50%, e.g., more than 60%, e.g., more than 75%) and / or less than 90%.

[0040] Example 32 (e.g., a use and / or process) is set up according to one of Examples 1 to 31, wherein the target, the substrate, and / or the arc discharge are exposed to a (e.g., molecular) reactive gas (e.g., oxygen and / or nitrogen and / or water vapor and / or ammonia) and / or an inert gas (e.g., Ar, Kr, and / or He). For example, the process atmosphere to which the target, the substrate, and / or the arc discharge are exposed may contain or consist of an Ar / Ch mixture.

[0041] Example 33 (e.g., a use and / or method) is set up according to one of Examples 1 to 32, wherein the layer and / or the target: comprise or consist of the ceramic, are transparent and / or electrically conductive. Example 34 is set up according to one of Examples 1 to 33, wherein one or more filters (also called deposition filters) are arranged between the target (or at least the target holder) and the layer (or at least the substrate holder), which are, for example, configured to influence the spatial propagation of a material stream emitted by the target, which is generated by the arc discharge, e.g., by means of a (e.g., electric and / or magnetic) field, thermally and / or mechanically. Examples of the deposition filter (or components thereof) include: an electromagnetic coil, an electrode, an aperture (for mechanical filtering), a (e.g., thermal) particle trap.Examples of the deposition filter (or components thereof) are designed to redirect and / or filter an ionized portion of the material flow.

[0042] Example 35 is set up according to one of Examples 1 to 34, wherein the layer is formed on a substrate which is held, for example, by means of a substrate holder.

[0043] Example 36 is set up according to one of Examples 1 to 35, wherein the target, layer and / or ceramic has an electrical conductivity of more than 10 S / m, e.g., 10 3 S / m.

[0044] Example 37 is set up according to one of Examples 1 to 36, wherein the target, layer and / or ceramic are electrically semiconducting.

[0045] Example 38 is set up according to any of Examples 1 to 37, wherein the target, layer and / or ceramic has or consists of one or more oxides, e.g. a mixed oxide.

[0046] Example 38 is set up according to one of Examples 1 to 37, wherein the target, layer, and / or ceramic exhibits a positive temperature resistivity (also known as the temperature coefficient of electrical resistance) at standard conditions (298.15 K). The temperature coefficient of electrical resistance (TOR) for indium tin oxide (ITO) varies but is generally positive and relatively small. For example, a typical ITO coating with a surface resistivity of 50 ohms / square has a TOR of about +2 10⁻⁶ per °C. However, ITO can, under certain circumstances, exhibit a negative TOR, particularly at lower temperatures or for specific applications such as resistance temperature detectors (RTDs).

[0047] Example 39 is set up according to one of Examples 1 to 38, wherein the electrical conductivity is referenced to standard conditions (298.15 K).

[0048] Example 40 is set up according to one of Examples 1 to 39, wherein the target, layer and / or ceramic are optically transparent (e.g. having a transmission coefficient of more than 50%).

[0049] Example 41 is set up according to one of Examples 1 to 40, wherein the target, layer and / or ceramic has or consists of a TCO.

[0050] Example 42 is an electrode (e.g., transparent and / or electrically conductive) provided by the layer according to one of Examples 1 to 41, preferably an electrode of an optoelectronic component. It shows

[0051] Figure 1 A shows a coating system according to various embodiments in a schematic side view or cross-sectional view;

[0052] Figures 1B and 2A each show aspects of arc discharge according to different embodiments in a schematic process diagram; and

[0053] Figure 2B shows a method according to various embodiments in a schematic flowchart. The following detailed description refers to the accompanying drawings, which form part thereof and in which specific embodiments in which the invention can be practiced are shown for illustrative purposes. In this respect, directional terminology such as "top," "bottom," "front," "back," "anterior," "rear," etc., is used with reference to the orientation of the described figure(s). Since components of embodiments can be positioned in a number of different orientations, the directional terminology serves for illustration and is in no way limiting. It is understood that other embodiments may be used and structural or logical modifications may be made without deviating from the scope of protection of the present invention.It is understood that the features of the various exemplary embodiments described herein can be combined with one another, unless specifically stated otherwise. The following detailed description is therefore not to be interpreted in a limiting sense, and the scope of protection of the present invention is defined by the appended claims.

[0054] Within the scope of this description, the terms "connected," "connected," and "coupled" are used to describe both direct and indirect connections (e.g., resistive and / or electrically conductive, such as an electrically conductive connection), direct or indirect connections, and direct or indirect couplings. In the figures, identical or similar elements are designated with identical reference numerals where appropriate. According to various embodiments, the term "coupled" or "coupling" can be understood as a connection and / or interaction (e.g., mechanical, hydrostatic, thermal, and / or electrical), e.g., direct or indirect. Several elements can, for example, be coupled to one another along an interaction chain, along which the interaction can be exchanged, e.g., a fluid (then also referred to as fluid-conducting coupled).For example, two coupled elements can interact with each other, e.g., a mechanical, hydrostatic, thermal, and / or electrical interaction. A coupling of several vacuum components (e.g., valves, pumps, chambers, etc.) can involve fluid coupling.

[0055] Depending on the specific embodiment, "coupled" can be understood as a mechanical (e.g., physical) coupling, for example, by means of direct physical contact. A coupling can be designed to transmit a mechanical interaction (e.g., force, torque, etc.).

[0056] The term "control device" can be understood as any type of logic-implementing entity that may, for example, have circuitry and / or a processor capable of executing software stored in a memory medium, firmware, or a combination thereof, and issuing instructions based on that software. The control device can be configured, for example, using code segments (e.g., software) to control the operation of a system (e.g., its operating point), such as a machine or plant, or at least its kinematic chain.

[0057] The term "processor," as used herein, can be understood as any type of entity that permits the processing of data or signals. The data or signals can, for example, be processed according to at least one (i.e., one or more than one) specific function performed by the processor. A processor may be an analog circuit, a digital circuit, a mixed-signal circuit, a logic circuit, a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a programmable gate array (FPGA), an integrated circuit, or any combination thereof. Any other type of implementation of the respective functions, which are described in more detail below, may also be understood as a processor or logic circuit.It is understood that one or more of the process steps described in detail herein can be executed (e.g., implemented) by a processor through one or more specific functions performed by the processor. The processor can therefore be configured to perform one of the processes described herein or its components for information processing. The term "actuator" (e.g., comprising an actuator) can be understood as a converter designed to influence a state, a process (e.g., a coating process), or a device in response to a control signal. The actuator can convert a control signal supplied to it (by means of which the control is effected) into mechanical movements or changes in physical quantities such as pressure or temperature.An actuator can be configured to influence the current state (also referred to as the operating point) of the process (e.g., its manipulated variable), which is supplied by the actuator. This influence can be direct or indirect. The manipulated variable and the controlled variable can, for example, differ from each other. The controlled variable (e.g., pressure) can then be a function of one or more manipulated variables (e.g., voltage).

[0058] According to various embodiments, the vacuum chamber can be provided by means of a chamber housing in which one or more chambers are provided. The chamber housing can, for example, be coupled to a pump arrangement, e.g., a vacuum pump arrangement (e.g., gas-conducting), to provide a negative pressure or a vacuum (vacuum chamber housing) and be designed to be stable enough to withstand the effects of atmospheric pressure in the evacuated state. The pump arrangement (comprising at least one vacuum pump, e.g., a high-vacuum pump, e.g., a turbomolecular pump) can enable the removal of some of the gas from the interior of the processing chamber, e.g., from the processing space. Accordingly, one or more vacuum chambers can be provided in a chamber housing. In other words, the chamber housing can be configured as a vacuum chamber housing.A coating chamber can be set up as a vacuum chamber.

[0059] The term "vacuum pressure" here refers to a negative pressure in the vacuum range (i.e., a pressure of less than 0.3 bar), e.g., a pressure in a range of approximately 10 mbar to approximately 1 mbar (in other words, rough vacuum) can be provided, or less, e.g., a pressure in a range of approximately 1 mbar to approximately 10 3 mbar (in other words, fine vacuum) or less, e.g., a pressure in a range of approximately 10‰. 3 mbar to approximately 10 7 mbar (in other words, high vacuum) or less, e.g., a pressure of less than high vacuum, e.g., less than approximately 10 7 mbar.

[0060] Arc vaporization is the process of converting a solid material into a gaseous state by means of an electric arc discharge. The target material, once converted into a gaseous state, can be used as a coating material, for example, as the coating material.

[0061] Arc evaporation, i.e., evaporation by means of an arc discharge, belongs to the class of thermal evaporation processes. These processes are characterized by the fact that a material to be evaporated (here also referred to simply as the coating material) is heated to such an extent that it transitions into its gaseous state (also referred to as material vapor) (e.g., by absorbing latent heat). A molten state of the material may (but does not necessarily) occur as an intermediate step. For example, it can evaporate from the molten state or sublimate directly. An arc discharge is a form of gas discharge in which the plasma formed is drawn into a tube (or, more vividly, a thin thread, the so-called arc). Within this plasma tube, high gas temperatures (e.g., in the range of approximately 5000 Kelvin to approximately 50000 Kelvin) and high currents (e.g.,The arc discharge (in a range of approximately 2000 amperes or more) and the gas pressures used to convert the coating material into the gaseous phase (also known as evaporation) are required. The arc discharge, and thus the plasma formation, can be of short duration, resulting in pulsed operation. Arc evaporation is distinct from the process of cathode sputtering, in which the plasma is generated by means of a (e.g., continuous or pulsed) glow discharge.

[0062] In laser-induced arc evaporation, a laser is used to precisely trigger the ignition of an arc discharge, which locally stimulates the formation of a plasma (also known as plasma formation). This process is also called laser-induced or laser-assisted arc discharge or laser arcing. Within the vacuum chamber between the anode and cathode, the laser generates a very short pulsed plasma (to ignite the initial plasma). This initial plasma, lasting from a few tens of nanoseconds to 100 nanoseconds, is then amplified in pulse length and power by an arc discharge using an electrical (pulse) power supply (e.g., a pulsed current source). The resulting plasma reduces the impedance between the cathode and anode, so that a voltage applied between them causes a discharge current to flow through the plasma. In other words, a pulsed arc discharge can be induced using a laser.In this process, the laser is guided across the cathode using a mirror system, allowing the location of the arc discharge to be precisely controlled. The laser thus influences the point of discharge ignition on the cathode, ensuring uniform, contactless ablation of the target material.

[0063] An excitation source (e.g., a laser source) is a device configured to generate an excitation pulse, such as a radiation pulse, a power pulse (e.g., delivered as a current or voltage pulse), or similar. The excitation source is generally configured to initiate (e.g., trigger) and / or sustain a plasma discharge (e.g., plasma formation and / or electrical charge transfer by means of the plasma) using the excitation pulse. For example, an electrical voltage pulse can be used as the excitation pulse to trigger the plasma discharge. A laser source is a device configured to generate a laser beam. A laser beam is understood to be a directed (e.g., collinear and / or collimated) propagation of electromagnetic waves, which is, for example, stimulated and / or coherent.The laser source can, for example, include an electromagnetic resonator, which stimulates the emission of the laser beam. In contrast to a continuous-wave laser, a pulsed laser source generates pulsed laser radiation (also called a laser pulse). The laser pulse can be generated by pulsed excitation or, for example, by a Q-switch within the laser itself. Examples of laser sources include gas lasers (e.g., carbon dioxide lasers) and solid-state lasers (e.g., semiconductor lasers).

[0064] A "pulse" in relation to a physical quantity (for example, power, then also referred to as a power pulse) can be understood as a change in the quantity over time such that the value of the quantity (e.g., starting from an initial value, for example, zero) increases, exceeds a maximum (also referred to as a peak value), and then decreases again (e.g., to the initial value).

[0065] A plasma can be generated using a so-called working gas (also known as a plasma-forming gas). Depending on the specific design, the working gas can be a gaseous material that is unreactive, meaning it participates in few or no chemical reactions. A working gas can be defined by, or adapted to, the target material used. For example, a working gas can be a gas or a gas mixture that does not react with the target material to form a solid. The working gas can be, for example, a noble gas (e.g., helium, neon, argon, krypton, xenon, radon) or several noble gases. The plasma can be generated from the working gas, which essentially causes the target material to be atomized. If a reactive gas is used, it can have a higher chemical reactivity than the working gas, e.g.,Regarding the target material: In other words, the atomized target material can react faster (i.e., form more reaction product per unit time) together with the reactive gas (if present) than together with the working gas (e.g., if it reacts chemically with the working gas at all). The reactive gas and the working gas can be supplied together or separately as a process gas (e.g., as a gas mixture), for example, via the gas supply device.

[0066] In this context, an electrode is understood to be an electrically conductive and / or metallic object (e.g., a body or a composite of several bodies) to which an electrical potential (also referred to as electrode potential) can be applied and / or to which the electrical potential can be changed during operation. The electrode can, for example, have one or more plate-shaped components (also referred to as electrode plates), one or more wire-shaped components (also referred to as electrode wires), one or more beam-shaped components (also referred to as electrode beams), and / or one or more tubular components (also referred to as electrode tubes). For example, the cathode can be provided by means of the (e.g., tubular) target. The electrode can also be electrically coupled to a circuit, which, for example, is configured to provide the electrode potential.Depending on the implementation, an electrode can be configured as either an anode or a cathode and operated accordingly. The electrode can, for example, provide the electrical power for the coating process. The term "coating material" here generally refers to a material used in a coating process that forms one or more layers (also called coating). The coating material can, for example, have the same chemical composition as the layer (then also called the coating material) or react chemically with the coating material. Alternatively or additionally, the coating material can be arranged in a crucible (then also called the evaporation material).In the context of the target, the term coating material refers to the material of the target (also referred to as target material), in the context of the layer, the material of the layer (also referred to as layer material), and in the context of layer formation, the gaseous material by means of which the layer is formed (e.g., the layer material, the target material, which may, for example, be a reactant of the layer material).

[0067] This refers, among other things, to a rotational axis, particularly for a rotatably mounted component (e.g., target or substrate) and / or a bearing device designed to support it (e.g., the target holder or substrate holder). In this context, it can be understood that what is described for the rotational axis can apply analogously to a longitudinal axis, for example, if no rotatable bearing is present.

[0068] The term "ceramic" is used here, among other things, in the context of a material (then also referred to as "ceramic") or an object made from it, e.g., a layer (also referred to as a ceramic layer) or a target (also referred to as a ceramic target) made from it. In this context, "ceramic" and "ceramic" are understood as inorganic and non-metallic, for example, exhibiting low toughness. For example, the ceramic may contain a chemical compound, such as an oxide, a nitride, a carbide, an oxynitride, and / or a mixture thereof. A chemical compound (e.g., the ceramic) can be understood as a material consisting of atoms of two or more chemical elements (e.g., "M" and "R"), where "M" may, for example, denote a metal atom and / or "R" a reactive atom (e.g., an oxygen atom, a nitrogen atom, or a carbon atom). With regard to ceramics, a metal oxide, e.g.,ITO or AZO, referred to as ceramics, which can be applied analogously to any other chemical compound of a metal (e.g., indium and / or zinc) that is ceramic.

[0069] According to various embodiments, a ceramic can be provided or made electrically conductive and / or transparent, for example, by exhibiting a multitude of impurities. Intuitively, the electrical and / or optical properties of the ceramic (e.g., its electrical conductivity and / or transmittance), or of an object made from it, can be a function of the chemical composition of the ceramic, for example, a function of the density (i.e., number per volume or per atom) of impurities, which, for instance, influence the behavior of electrons. Examples of impurities include: foreign atoms (also called dopants) and / or vacancies (also called lattice vacancies), which can be formed, for example, by introducing the foreign atoms (also called doping) and / or by introducing lattice vacancies (also called substoichiometry).

[0070] The term "stoichiometric" can be understood in the context of a material as a chemical compound (e.g., MRi- x , MR2-X, MR3-X, M2R3-X, etc.) and / or crystal lattice which(s) is essentially saturated and / or has no vacancies (i.e., x=0). The vacancies here may refer to a reactive material “R”, e.g., oxygen and / or nitrogen. For example, a stoichiometric oxide may be essentially completely oxidized, i.e., upon heating or other chemical activation, it essentially no longer accepts oxygen (i.e., more generally, it may be saturated with the reactive material). By analogy, a stoichiometric nitride may be essentially completely nitrated, i.e., upon heating or other chemical activation, it essentially no longer accepts nitrogen.

[0071] Substoichiometric in this context can be understood as having a large number of vacancies (i.e., x > 0, e.g., x > 0.1) (more generally referred to as substoichiometry), e.g., oxygen vacancies and / or nitrogen vacancies. These vacancies can be sites in the crystal lattice of the material that remain unoccupied. If a substoichiometric material is heated and / or chemically activated, it can occupy these vacancies, e.g., by absorbing the reactive material (oxygen or nitrogen) and incorporating it into its crystal lattice.

[0072] In general, a stoichiometric material can have a proportionally lower number of vacancies (e.g., essentially no vacancies) than a substoichiometric material. Alternatively or additionally, the stoichiometric material can have a lower absorption coefficient than a substoichiometric material. For example, the absorption coefficient of the material can increase with a proportionally increasing number of vacancies.

[0073] The term "doped" in connection with a material (e.g., a ceramic), which in this context is also referred to as a support material (or matrix material or base material), indicates that a large number of foreign atoms (then also referred to as dopants) have been introduced into the support material (also referred to as doping), for example, with a proportion in the range of approximately 0.1 ppm (parts per thousand) to approximately 100 ppm (parts per thousand), relative to the atoms of the support material. Examples of support materials (e.g., a ceramic) that can be doped include: tin oxide, indium oxide, and zinc oxide. Examples of doped materials (e.g., ceramics) include: tin-doped indium oxide (also referred to as indium tin oxide, or ITO for short), antimony-doped tin oxide (ATO), fluorine-doped tin oxide, and aluminum-doped zinc oxide (AZO).

[0074] Electrically conductive is understood here to mean a (specific) electrical conductivity of more than approximately 10 4 exhibiting Siemens per meter (S / m) (e.g. at 20°C), e.g. as approximately 10 5 S / m, e.g. as approximately 10 6 S / m (then also described as highly conductive). Electrically insulating is understood here as having an electrical conductivity of less than approximately 10 Siemens per meter (S / m) (e.g., at 20°C), e.g., approximately 10 5 S / m, e.g. as approximately 10 6 S / m. The electrical conductivity of a material is the inverse of its (specific) electrical resistance and is used interchangeably in this context; thus, a conductivity of 1 S / m corresponds to a specific resistance of 1 Q'm and a specific conductivity of 10 3 S / m resistance 1000 Qm

[0075] The term "transparent" (e.g., also translucent) can be understood here as having a transmission coefficient (also referred to as transmission factor) of more than approximately 25%, e.g., approximately 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%. This can also be the case, for example, with a translucent object (e.g., a layer).

[0076] Regarding optical properties, such as transparency, transmittance, etc., it can be understood that these optical properties are related to a wavelength or wavelength range of optical radiation (e.g., light). Fundamentally, the optical properties of a solid (e.g., a layer or a target) can be a function of the wavelength of the optical radiation, the optical density of the solid, the path length of the optical radiation through the solid, and optionally, the nature of the interface(s) of the solid through which the optical radiation passes. Optical radiation (e.g., light) can be understood as radiation in the ultraviolet (also known as UV) range, the visible range, or the infrared (also known as IR) range, e.g., the near-infrared range. The UV range is the wavelength range from 100 nanometers (nm) to 400 nm.The visible range is the wavelength range from 400 nm to 780 nm. The infrared range is the wavelength range from 780 nm to 1 mm (millimeter). The near-infrared range is the wavelength range from 780 nm to 2500 nm.

[0077] Regarding the substrate, an exemplary implementation is provided using amorphous silicon (also referred to as aSi or a-Si), polycrystalline silicon (also referred to as poly-Si), and / or silicon doped with a chemical element X (also referred to as X:Si), all of which have a support structure (e.g., a solar cell precursor). For example, the substrate may have a silicon wafer (also referred to simply as a wafer) as its support. It can be understood that what is described for the silicon wafer can apply analogously to substrates of other types, which, for example, do not necessarily have a wafer and / or silicon as a semiconductor. For example, what is described for silicon can apply analogously to any other material, e.g., another semiconductor material.

[0078] Fig. 1A illustrates a coating system according to various embodiments 100a in a schematic side view or cross-sectional view, preferably in use according to Example 1 and / or comprising a coating device. The coating device has a target holder 112h and an anode 132, which are arranged one behind the other, for example, along an emission direction 101. In operation, the coating device can be arranged, for example, opposite a substrate holder 104, e.g., with the emission direction 101 directed towards the substrate holder 104.

[0079] The target holder 112h can have a receiving area for receiving the target 112, which is held by means of the target holder 112h, and can be disassembled, for example, outside of the operation of the coating system.

[0080] An emission axis 111 (also called a propagation axis) extends along an emission direction 101, which is directed from the target holder 112h towards the substrate holder 104. The anode 132 and the substrate holder 104 are arranged one behind the other along the emission direction 101. An exemplary implementation of the emission axis 111 is oriented perpendicular or parallel to the gravitational direction 105 (i.e., the direction of the gravitational force).

[0081] An exemplary implementation of the target 112 is rotatably mounted by means of a bearing device as a target holder (not shown). This extends the service life of the target, especially if it is rotated during operation, e.g., during arc vaporization. The axis of rotation of the target 112 can, for example, be oriented transversely to the emission axis 111.

[0082] By analogy, an exemplary implementation of the substrate holder 104 has a bearing device by means of which the substrate or a transport roller can be rotatably mounted. The axis of rotation of the substrate holder 104 can, for example, be along the axis of rotation of the target 112. For example, the transport roller of the substrate holder 104 can be configured to transport the substrate along a specific direction, e.g., past the target 112. In this case, the substrate can be plate-shaped or strip-shaped.

[0083] The anode 132 is configured to induce the formation of an arc discharge during operation, which is mediated between the target and the anode. By means of the arc discharge, a portion of the target 112 can be converted into the gaseous phase, and the material thus separated from the target 112 (at least partially as plasma) propagates in the emission direction 101 towards the substrate holder (also referred to as the material stream 116, see Fig. 1B). Fig. 1B illustrates aspects of the arc discharge according to various embodiments 100b in a schematic process diagram, preferably configured according to embodiment 100b and / or used according to one of Examples 1 to 19, by means of which arc evaporation (for example, for laser-induced arc evaporation) can be carried out.

[0084] These aspects of arc discharge can be implemented, for example, by means of a device such as a coating system and / or a control device, and / or by means of the method. For the sake of simplicity, reference is made to the implementation using the coating system, whereby what is described here can be applied analogously to each of the other implementations. Pulsed signals are represented by a circumflex… A " marked. Furthermore, reference is made to a laser-excited arc discharge, in which an arc discharge is excited by means of a laser pulse.

[0085] An exemplary implementation of the coating system is integrated into a vacuum assembly. The vacuum assembly includes a vacuum chamber 102. Each vacuum chamber 102 can optionally have a chamber lid that seals the interior of the vacuum chamber 102 in a vacuum-tight manner. The arc discharge can accordingly be exposed to a process pressure (e.g., vacuum pressure) and / or a process gas. The vacuum assembly also includes a coating device 108. The coating device 108 can be configured to coat the substrate 104 using a laser-induced arc discharge.

[0086] The gas pressure (also referred to as process pressure) used to operate the coating device 108 and / or the process gas (e.g., a gas or gas mixture) supplied to the coating device 108 can vary considerably depending on the application. For example, the process pressure can range from approximately 10 mbar (millibar) to approximately 5–10 4 mbar. It is not necessarily required that gas be supplied; in which case the gas pressure can, for example, be less than 10 5mbar. For example, the process gas may contain one or more of the following gases: oxygen (e.g., molecular oxygen, i.e., O2), nitrogen (e.g., molecular nitrogen, i.e., N2), hydrogen (e.g., molecular hydrogen, i.e., H2), one or more hydrocarbon compounds, or a mixture thereof. The process gas may contain the working gas (e.g., an inert gas) and / or a reactive gas. The optional reactive gas may, for example, contain hydrogen.

[0087] An exemplary implementation of the coating system includes a coating device 108, which has a target holder (not shown) for holding the target 112. The target 112 can generally contain or consist of a substance to be vaporized (e.g., the coating material) that is to be converted into a gaseous state (also referred to as vaporization). The target holder can, for example, provide the target 112 with a rotational axis and can be configured to rotate the target 112 (when held in the target holder) around the rotational axis, e.g., by means of a drive device. The coating device 108 optionally includes a laser source 110.

[0088] An exemplary implementation of the coating device 108 further includes the laser source 110 as an optical excitation source, which is configured to generate one or more than one laser pulse 114 (i.e. pulsed laser beam) and direct it towards the target holder, or at least the target 112.

[0089] In an exemplary implementation of the operation of the vacuum arrangement, the target 112 is held in the target holder and repeatedly irradiated with a laser pulse 114 by the laser source 110. This laser pulse 114 can excite (e.g., induce) an arc discharge at the target 112, in which part of the target is converted into material vapor. The target 112 can be operated as the cathode in this process. Therefore, the target holder can also be referred to as a cathode end block.

[0090] A cathode end block (hereinafter also referred to simply as an end block) is a device designed to hold and supply a cathode, for example, with torque to rotate the cathode, with electrical energy, and optionally with a cooling fluid. To provide the torque, the end block may have a drive device (e.g., a motor) or at least be coupled to one. The end block may be mounted inside a vacuum chamber, for example, at a through-hole in its wall (also referred to as a supply port). The electrical energy and / or the cooling fluid (and optionally the torque) can be supplied to the end block through the supply port. Optionally, one or more additional media may be supplied to the end block to supply the cathode, for example, data for controlling and / or reading a sensor.

[0091] One exemplary implementation of Target 112 is tubular (then also referred to as a tube target). Target 112 can, for example, have a tubular support (a so-called support tube) on which a coating material (e.g., brittle and / or fragile) can be attached. The diameter of the tube target can, for example, range from approximately 10 cm (centimeters) to approximately 50 cm, e.g., approximately 20 cm or more.

[0092] The vacuum arrangement can include one or more electrical supply devices 118 as an electrical excitation source (which can also be referred to as an electrical power supply). Each electrical supply device 118 can be configured to provide one or more operating voltages (e.g., a DC voltage), e.g., pulsed (also referred to as a voltage pulse). Alternatively or additionally, the electrical supply device 118 can include, for example, a pulse generator (preferably configured according to Example 22) for each power pulse to be provided.

[0093] The operating voltage is applied between the anode and the target holder. This operating voltage can be configured to allow an electric current to be introduced between the cathode and the anode, but without initiating a spontaneous discharge (uncontrolled start of the discharge). Alternatively or additionally, at least a portion of the electric current of the arc discharge can be introduced between the cathode and a reference potential (e.g., electrical ground and / or provided by the chamber housing), for example, up to two-thirds of the electric current introduced by the cathode. For this purpose, the operating voltage can be lower than the ignition voltage (i.e., the voltage at which an arc discharge is ignited) and higher than the operating voltage (i.e., the voltage at which an arc discharge occurs). For example, the anode potential can be in the range of approximately 10 to approximately 20 V.A cathode potential at the cathode can be negative (e.g., with respect to the reference potential, such as electrical ground) and / or its magnitude can be greater than approximately 10 V (e.g., 20 V, 50 V, 100 V, 180 V) and / or less than approximately 400 V (e.g., 350 V, 200 V, 50 V). Examples of operating voltages are: for ITO as the target material: 327 V; for SnÜ2 as the target material: more than 400 V. After ignition of the arc discharge, the operating voltage can reduce to the so-called firing voltage, which, for example, can be < 50 V for ITO and / or AZO as the target material; or approximately 200 V for SnÜ2 as the target material.

[0094] An exemplary implementation of the electrical power supply device 118 is configured to generate a first electrical power pulse 120. The first electrical power pulse 120 can be applied to the target 112. The first electrical power pulse 120 can be configured to electrically supply the arc discharge (induced by the laser pulse 114) (e.g., via the target 112). For this purpose, the target holder can be electrically coupled to the electrical power supply device 118.

[0095] The vacuum assembly can, for example, include a control device 124. The control device 124 can be configured to control the laser source 110. For example, the control device 124 can drive the laser source 110 to generate the laser pulse 114 and thus initiate a laser-induced arc discharge. The control device 124 can also be configured to control the electrical supply device 118 and / or the laser source 110. For example, the control device 124 can drive the electrical supply device 118 to generate the first electrical power pulse 120 according to a (first) target power pulse (e.g., a target current pulse). The first electrical power pulse 120 can be mediated by means of a current pulse generated (or controlled) by the electrical supply device 118.

[0096] If reference is made here to a specification, such as a target power pulse and / or its properties (e.g., a target power pulse, a target time delay, and / or a target frequency, etc.), this can be implemented by means of code segments, which can be stored, for example, in a data memory belonging to the control device 124. The code segments can be stored in the data memory in a suitable manner, for example, as a list (e.g., a table), a series of values, as an algorithm, etc.

[0097] Control by the control device 124 can be carried out according to an operating sequence. This operating sequence can be stored in the data memory in a suitable manner, for example as an algorithm or in another way by means of code segments.

[0098] An exemplary implementation of the drive device is configured to excite a rotational movement of the target 112 around a rotational axis. For example, the target holder can include the drive device (e.g., an electric motor) configured to supply torque to the target. The control device 124 can be configured to control the drive device in order to control the rotational movement (e.g., a rotational frequency).

[0099] By means of the electric arc, the (e.g., solid) target can be at least partially converted (for example, at the discharge point on target 112) into the gaseous state (also referred to simply as the gaseous state or vapor). This conversion can also be described simply as evaporation, but can generally also involve sublimation (i.e., a direct transition from the solid state of the target material to the gaseous state). The material released from target 112 by means of the electric arc discharge (e.g., vaporized from target 112) can form a material stream 116 away from target 112.

[0100] During operation of the vacuum arrangement, one (or more than one) substrate 106 can be coated by means of the material flow 116. For this purpose, the vacuum arrangement can have a substrate holder 104, which is configured to hold and / or transport one or more substrates 104 (then also referred to as a transport device 104). The substrate holder 104 can be arranged in the vacuum chamber 102. In various embodiments, the distance between the axis of rotation and the substrate holder can be in a range of approximately 410 mm to approximately 750 mm.

[0101] An exemplary implementation of the transport device 104 is configured to transport a ribbon-shaped substrate (also referred to as a ribbon substrate), e.g., from roll to roll. The transport device 104 can hold a first roll from which the ribbon substrate is unwound, and a second roll onto which the ribbon substrate is wound after being exposed to the material flow 116.

[0102] An exemplary implementation of the electrical supply device 118 is configured to generate a second electrical power pulse 122 as a bias potential. The second electrical power pulse 122 can be configured to accelerate the (e.g., ionized portion of) material flow 116 away from the target 112 or towards the substrate holder 104. For this purpose, the substrate holder 104 can be electrically coupled to the electrical supply device 118. The second electrical power pulse 122 can influence the kinetic energy with which the material of the material flow 116 impacts the substrate 106.

[0103] Depending on various aspects, the laser pulse 114, the first electrical power pulse 120, and optionally the second electrical power pulse 122, can be linked together (e.g., by means of the operating sequence), for example, in such a way that they overlap in time. For this purpose, the control device 124 can, for example, have a clock generator that implements a linkage of the laser pulse 114, the first electrical power pulse 120, and optionally the second electrical power pulse 122 (e.g., their time dependency).

[0104] Depending on various aspects, the substrate 106 can be coated by repeatedly generating an arc discharge with an associated material flow 116 (also referred to as discharge ignition) according to a target frequency. Discharge ignition here refers to the (e.g., repeated) excitation of the arc discharge by means of one or more pulses, for example, by means of the laser pulse 114 and / or by means of the first electrical power pulse 120. The laser pulse 114, the first electrical power pulse 120, and optionally the second electrical power pulse 122 can be generated per discharge ignition.

[0105] The supply device 118 described herein can also be implemented by means of one or more than one single device, of which, for example, a first device generates the first power pulse and a second device generates the second power pulse.

[0106] Figure 2A illustrates aspects of the arc discharge according to various embodiments 200a in a schematic process diagram, preferably configured according to one of embodiments 100a to 100b and / or used according to Example 1. The arc discharge 214 is shown, which mediates a charge exchange between the target 112 and the anode 132, for example by means of a plasma 202 to which the target 112 is exposed. An exemplary implementation of the arc discharge 214 (also referred to as an arc) is excited by means of a pulsed laser beam as laser pulse 114, which is directed at the target 112. For this purpose, the plasma 202 can be formed by converting a part of the target (also referred to as the impact site T(Tx, Ty)), at which the laser beam is directed, into a gaseous phase by means of the laser beam and thereby ionizing it.The plasma 202 spreads away from the target 112, thereby promoting the charge exchange between target 112 and anode 132, until the arc discharge 214 occurs (for example, when the self-ignition threshold between target 112 and anode 132 falls below the potential difference between target 112 and anode 132).

[0107] The region 112f of the target 112, in which the arc discharge enters the target 112 (also referred to as the foot point region 112f), is a function of the point of impact T(Tx, Ty) of the laser beam on the target 112.

[0108] The point of impact T(Tx, Ty) of the laser beam on the target 112 is generally a function of the geometry of the target, its orientation, and / or the propagation direction R(Rx, Ry) of the laser beam, which can, for example, be provided or made time-dependent, i.e., Rx = Rx(t) and / or Ry = Ry(t). Here, the more easily understood Cartesian coordinates are used, although it should be understood that what is described here can be expressed in any other mathematical form (e.g., of coordinates).

[0109] An exemplary implementation of the time-dependent propagation direction is provided as a default (e.g., a target distribution). For example, Rx=Rx(t) and / or Ry=Ry(t) can be implemented as a default, e.g., as a target distribution, e.g., via the control device and / or stored on a storage medium. The point of impact T(Tx, Ty) can be changed, for example, by controlling a scanner or another optical actuator (e.g., a mirror-pinhole disc or galvo scanner).

[0110] An exemplary implementation of laser pulse 114 is provided with a time dependency, e.g., frequency (also referred to as clock), with which the laser beam is emitted, for example, specified by the clock. For instance, the point of impact T(Tx, Ty) of the laser beam can be shifted by a distance S along the target's axis of rotation for each laser pulse. This promotes uniform ablation of the target. The distance S can be predefined, e.g., defining a desired spatial distribution.

[0111] According to one exemplary implementation of the laser beam, it is provided by a pulsed laser, which, for example, provides a power of 15–20 millijoules (or more) and / or a pulse duration (duration of the laser pulse) in the range of 10 ns (nanoseconds) to 200 ns (or less). One example of the laser beam has a pulse duration of 15 mJ per pulse and a duration of 40 ns.

[0112] According to working example 1, the formation of the layer (also referred to as coating process or layer formation) takes place in a evacuated vacuum chamber, the base pressure of which at room temperature is no more than 5-10 3 Pascal is (e.g. at a base pressure of 10 5 mbar). The substrate can optionally be heated, which can improve the layer quality. The substrate and / or the target can be exposed to a gas mixture of argon and oxygen. The target consists of doped tin oxide, which is doped, for example, with aluminum (e.g., 4 at% or more). The coating material emitted from the target can be filtered to remove particles by means of a filter comprising one or more electromagnetic coils (also called a filter coil) and then directed onto the substrate.

[0113] According to working example 2, the layer is formed by means of a pulsed arc discharge with a nearly sinusoidal current waveform, e.g., with a duration between 0.1 milliseconds and 1 millisecond and / or with an amplitude of more than 0.5 kiloamperes, e.g., at 0.8 kiloamperes. The arc discharge can be repeatedly excited, for example, at a frequency of more than 100 times per second, e.g., 300 times per second. The high pulsed current drives the cathode spots radially at high speed, but before they touch the cathode edge, the arc is switched off and a new cycle is started. For example, the target can be rotated at a frequency of 24 revolutions per minute.

[0114] According to working example 3, the arc discharge provides a flow of material to the substrate with an ion energy in a range of approximately 10 electron volts to approximately 50 electron volts.

[0115] According to working example 4, the target and / or the ceramic of the target contains ITO, for example, a mixture of ln₂O₃ and SnO₂ in a ratio of 90 / 10 wt.%. The layer thus formed (also referred to as the ITO layer) can have a resistivity of less than 500 πq⁻¹ cm (microohms per centimeter), e.g., 200 πq⁻¹ cm, and / or a transmittance of a

[0116] Wavelength of 550 nm of more than 90% per 100 nm (nanometer) layer thickness (e.g. after subsequent annealing of the layer).

[0117] Fig. 2B illustrates a method according to various embodiments 200b in a schematic flowchart, preferably configured according to embodiments 100a to 100b. The method comprises, in 201, excitation of an arc discharge by means of a laser to which a ceramic target is exposed; and in 203, formation of a layer which has or consists of an electrically conductive ceramic by means of the arc discharge.

[0118] An exemplary implementation of the method is carried out using a pulsed high-current source, which provides a potential difference (also referred to as terminal voltage) between the anode and the target that is smaller than a self-ignition threshold. The arc discharge is ignited by means of a (e.g., ultra-)short-time laser pulse. The arc discharge is switched off by interrupting the current flow supplied to the arc discharge, for example, by switching off the power supply device (e.g., pulsed current source) that powers the arc discharge.

[0119] According to various embodiments, it has been found that a short duration of the pulsed arc discharge (also referred to as pulse duration or discharge time) inhibits particle and / or droplet formation, thus improving the layer quality. According to one exemplary implementation of the method, the discharge time of the arc discharge is less than approximately 10 ms (milliseconds), e.g., less than approximately 500 pis (or 100 pim), e.g., less than approximately 10 ns (nanoseconds).

[0120] According to an exemplary implementation of the process, a ceramic target (optionally with a small amount of reactive gas added) is used for the low-damage deposition of TCO, e.g., for a photovoltaic component (e.g., a solar cell). Particularly for the production of a photovoltaic component, high demands are placed on the layer, e.g., the transparent electrode, to promote high efficiency.

Claims

Patent claims 1. Using a laser-excited arc discharge (214) to form a layer by means of a target (112) which is exposed to the arc discharge (214) and which has or consists of a ceramic, wherein the target (112) is electrically conductive.

2. Use according to claim 1, wherein the excitation of the arc discharge (214) is carried out by means of a laser which is preferably configured to direct a laser beam onto the target (112).

3. Use according to claim 1 or 2, wherein the formation of the layer is carried out by means of a material stream emitted from the target (112) which is generated by means of the arc discharge (214).

4. Use according to any one of claims 1 to 3, wherein the excitation of the arc discharge (214) is carried out several times in succession according to a spatial target distribution with which the target (112) is exposed to the arc discharge (214).

5. Use according to any one of claims 1 to 4, wherein the target (112) is ceramic and comprises a chemical compound of oxygen as a ceramic.

6. Use according to claim 5, wherein the chemical compound comprises a metal, preferably aluminium, indium, titanium, niobium, zirconium, tin and / or zinc.

7. Use according to any one of claims 5 to 6, wherein the ceramic is an oxide semiconductor and / or doped.

8. Use according to any one of claims 1 to 7, wherein the layer is substoichiometric.

9. Use according to any one of claims 1 to 8, wherein the target (112) and the layer differ from each other at least temporarily in an electrical potential applied to them.

10. Use according to any one of claims 1 to 9, wherein a filter is arranged between the target (112) and the layer, which is configured to filter out particles emitted by the target (112).

11. Use according to any one of claims 1 to 10, wherein the layer is transparent.

12. Use according to any one of claims 1 to 11, wherein the arc discharge (214) is terminated by time triggering and / or current control.

13. Use according to any one of claims 1 to 12, wherein the target (112) and / or the arc discharge (214) is exposed to a magnetic field.

14. Use according to any one of claims 1 to 13, wherein the layer provides a transparent, electrically conductive electrode, preferably an electrode of an optoelectronic component.

15. Vacuum arrangement comprising: • a vacuum chamber, • a coating device which is configured to excite an arc discharge (214) in the vacuum chamber by means of a laser to which a target (112) of the coating device, which has a ceramic and is electrically conductive, is exposed; • a substrate holder for holding a substrate in the vacuum chamber on which the formation of a layer takes place by means of the arc discharge (214).

16. Vacuum arrangement according to claim 15, wherein one or more filters are arranged between the target and the substrate holder, the filter being configured to influence the spatial propagation of a material stream emitted by the target, which is generated by means of the arc discharge.

17. Procedure, comprising: • Excitation of an arc discharge (214) by means of a laser which is exposed to a target (112) which has or consists of a ceramic and is electrically conductive; • Forming a layer by means of arc discharge (214).

18. Electrode produced by the method according to claim 17 and comprising the layer, preferably providing an electrode of an optoelectronic component.

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