Plasma electrode movably mounted in a process chamber of a CVD reactor

Abstract

The invention relates to a device for depositing a layer on a substrate (1) in a process chamber (4) located in a housing of a CVD reactor (3), comprising a gas inlet member (5) for introducing gases into the process chamber (4), comprising a gas outlet surface (8) with a plurality of gas outlet openings (6, 7) through which the gases can flow into the process chamber (4), and comprising at least one plasma electrode (10) to which an electrical voltage can be applied by a plasma generator (9) and which is designed to apply energy to a gaseous starting material in order to generate a plasma, the plasma electrode (10) being movably mounted in the process chamber (4).

Description

Description Plasma electrode that can be moved within a process chamber of a CVD reactor field of technology

[0001] The invention relates to a device for depositing a layer on a substrate in a process chamber arranged in a housing of a CVD reactor, with a gas inlet device for introducing gases into the process chamber, with a gas outlet surface having a plurality of gas outlet openings through which the gases can flow into the process chamber, with at least one plasma electrode that can be supplied with an electrical voltage by a plasma generator and which is configured to supply energy to a gaseous starting material in order to generate a plasma. State of the art

[0002] During the deposition of layers onto substrates in a process chamber of a CVD reactor, process gases introduced into the chamber via a gas inlet are decomposed pyrolytically or catalytically. The resulting decomposition products crystallize not only on the substrates but also on other surfaces within the process chamber exposed to the process gases. This undesirable parasitic growth generates impurities that contaminate substrates stored in the process chamber during subsequent processes. This reduces the efficiency and reproducibility of these subsequent processes and impairs the growth behavior of the layer being deposited on the substrates.

[0003] To remove such parasitic deposits from the surfaces of the process chamber, cleaning processes are typically carried out in the 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Process chambers are used in which cleaning gases, such as chlorine, hydrochloric acid, ammonium nitrate, hydrogen, or oxygen, are introduced. To enable these gases to form the radicals necessary for surface cleaning, comparatively high cleaning temperatures of several hundred degrees Celsius are required within the process chamber for an extended period. Particularly in a CVD reactor, where the walls or ceiling of the process chamber are directly cooled, a high heat output is required to raise the surface temperature of the process chamber, heated by the susceptor through thermal radiation, to the desired cleaning temperature. This results in high energy consumption for the heating equipment required to heat the susceptor.On the other hand, long cleaning processes in practice lead to considerable downtimes during which the CVD reactor is unproductive, meaning no growth processes can be carried out in the process chamber, thus significantly reducing the overall productivity of the CVD reactor.

[0004] EP 2876083 B1 discloses a device with a gas inlet element through which various gases can be fed into a process chamber. A plasma electrode, which can be subjected to an electrical voltage, is arranged in the gas inlet element and can be used to ignite a plasma in order to associate or dissociate gaseous starting materials. These gaseous starting materials can be precursor organases used in growth processes or cleaning gases used for cleaning a process chamber. The cleaning gases can be converted into cleaning radicals by means of the plasma to remove deposits from surfaces within the process chamber. The plasma electrode can be a plate forming a plurality of openings, arranged within the gas inlet element between two grounded shield electrodes, also designed as plates. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0005] US Patent 2002 / 012976 describes a CVD reactor with a showerhead gas inlet through which various process gases are fed into a process chamber. To convert the process gases into radicals, a plate-shaped plasma electrode is provided within the gas inlet above the gas outlet plate, through which the gases flow into the process chamber. To ignite a plasma within the gas inlet, the plate is energized by a voltage source located outside the reactor housing. The plate is contacted by means of an RF rod passing through the housing roof. The gas outlet plate is grounded by contact with the housing roof and acts as the counter electrode.

[0006] US Patent 2010 / 0072054 discloses a CVD reactor with a showerhead-type gas inlet for introducing various gases into a process chamber of the CVD reactor. The gas inlet has a gas outlet plate facing the process chamber, which features a multitude of gas outlet openings through which the gases can flow into the process chamber. The gas outlet plate acts as a plasma electrode, which can be energized by a voltage source located outside the process chamber. A grounded plate located below the gas outlet plate acts as a counter electrode. The plasma is thus generated between the gas outlet plate and the counter electrode.To prevent the released ions and electrons from entering the process chamber, several vertically stacked shielding plates are arranged between the counter electrode and the susceptor, each of which also has numerous gas outlet openings. The shielding plates adsorb the ions and reflect the electrons. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0007] German patent DE 102011056589 discloses a CVD reactor with a gas inlet designed as a showerhead, through which various gases can be fed into a process chamber bounded at the bottom by a heated susceptor. A thermally decoupled shielding plate is provided, separated from the cooled gas outlet surface of the gas inlet by a gap and heated by conduction or radiation from the susceptor. The shielding plate forms a plurality of gas outlet openings through which the gases can be fed into the process chamber. The shielding plate is arranged in the reactor housing in a height-adjustable manner relative to the showerhead and the susceptor.

[0008] Li et al. (Li, S., Tompa, GS, Moy, K. et al. In-situ plasma cleaning of stainless steel III-V MOCVD growth systems. J. Electron. Mater. 21, 149-156 (1992). https: / / doi.org / 10.1007 / BF02655830) disclose a device and a method for cleaning a process chamber of a MOCVD reactor using a plasma. A susceptor is arranged within the process chamber and is heated by a heating device located below the susceptor. Three electrodes are provided for generating the plasma: a first electrode is located above the susceptor, a second electrode is located below the heating device, and a third electrode is located at the bottom of the process chamber. Ar, CH4 (5% in H2), H2, CCl2F2, and Cl2 are introduced into the process chamber as cleaning gases, either individually or in combination. In addition, the plasma was used to etch III-V layers, such as GaAs and InP, onto substrates located on the susceptor. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Summary of the invention

[0009] The invention is based on the objective of taking measures to reduce the heat power applied to heating a process chamber of a CVD reactor and / or to selectively remove residues from the surfaces in the process chamber or from objects arranged in the process chamber, as well as a method.

[0010] The problem is solved by the device or method specified in the claims. The dependent claims not only represent advantageous further developments of the technical teachings specified in the dependent claims, but are also independent solutions to the problem.

[0011] The invention essentially provides for a plasma electrode arranged within the process chamber of a CVD reactor, which can be subjected to an electrical voltage by a plasma generator to generate a plasma. According to the invention, the plasma electrode is movable in a direction transverse to a plane of extension of the gas outlet surface. The gas outlet surface preferably extends in a horizontal plane, so that the direction of movement of the plasma electrode is preferably vertical. The plasma electrode can be arranged in any position within the process chamber and can optionally also be moved in a horizontal direction. The plasma electrode can preferably be a plate extending in a horizontal or vertical direction. Several such movable plasma electrodes can also be provided in a process chamber.The plasma electrode can preferably be thermally and electrically decoupled from other components arranged within the process chamber or from a contact position with grounded components. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Parts of the process chamber are brought into an electrically isolated position. One or more counter electrodes, particularly grounded ones, can be provided, formed by other components arranged in the process chamber. For example, the counter electrode can be a wall of the housing surrounding the process chamber, and / or a bottom of the process chamber, and / or a gas inlet through which various gases can be introduced into the process chamber, and / or the susceptor. When a voltage is applied to the plasma electrode, the plasma can initially form between the plasma electrode and the nearest counter electrode, i.e., the counter electrode that has the smallest vertical or horizontal distance to the plasma electrode.By increasing the voltage or power applied to the plasma electrode, the extent of plasma propagation within the process chamber can be controlled. The voltage can be adjusted so that the plasma extends beyond the volume formed between the nearest electrodes, covering the entire plasma electrode and the process chamber. The plasma can be excited, for example, by an alternating current (AC) or a direct current (DC). The frequency of the AC voltage can be in the range of Hz, kHz, MHz, or GHz, depending on the plasma power supply used. Plasma excitation can also be achieved with a pulsed waveform, which can be negative or positive (reverse polarity) or include discharge pauses, with the pulsed waveform being repeated at a frequency in the Hz, kHz, or MHz range.However, the plasma can also be excited by a combination of the aforementioned waveforms, for example by pulsed alternating current.

[0012] In a first embodiment of the invention, the plasma electrode can be arranged between the gas inlet organ and the susceptor. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 The gas inlet element can be configured as a flat plate or grid arrangement. The plate can preferably extend over the entire cross-sectional area of ​​the gas inlet element. However, the plate can also extend over only a portion of the cross-sectional area of ​​the gas inlet element. The gas inlet element can be configured as a "shower head" that has a cooled gas outlet surface facing the process chamber with a plurality of gas outlet openings through which gases can be fed into the process chamber. For example, the gas inlet element can be a shower head and the plasma electrode a shielding plate, as disclosed in DE 102021114868 A1.

[0013] The plasma electrode, for example the plate, can be electrically connected to the plasma generator, located either outside or inside the reactor housing, by means of a suitable contact element. The contact element can be, for example, an extendable rod, a cable, a folding contact, or a spring. The contact element can, for example, pass through an electrically insulated opening in the reactor housing. The contact element can also pass through the gas inlet, for example, through a channel opening into the gas outlet. The contact element can also be part of a lifting element that allows the plate to be moved within the process chamber. The plate can also be electrically connected to the plasma generator in other ways.

[0014] The plasma electrode can initially be positioned in close proximity, particularly at a distance of less than 1 mm or in contact with the cooled gas inlet housing wall, and then moved downwards away from the cooled gas outlet surface of the gas inlet element into a spaced position to separate the plasma electrode from the cooled 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 To thermally and electrically decouple the gas inlet housing wall of the gas inlet element. In the spaced position, the plasma electrode can be spaced away from the gas outlet surface of the gas inlet element by a clearance gap. In the spaced position, the plasma electrode can be arranged at a distance of more than 1 mm from the gas outlet surface. In the contact position, the plasma electrode can be in contact with the gas outlet surface, at least partially, or, in particular, at a distance of less than 1 mm from the gas outlet surface. During a coating process carried out in the process chamber, which in particular does not include plasma activation, the plasma electrode can preferably be arranged in the contact position. Decomposition products can be deposited on the surface of the plasma electrode facing away from the gas outlet surface of the gas inlet element.The clearance can be increased or decreased by vertically repositioning the plate. Lifting elements can be provided to allow the plasma electrode to be moved vertically. These lifting elements can be insulators or conductors connecting the plasma electrode to the plasma generator. The lifting elements can extend from the ceiling, side walls, or bottom of the reactor housing. The plate can be moved by means of an electric drive connected to the lifting elements or manually. Preferably, the plasma electrode can be moved to a position at a distance from the gas outlet surface of the gas inlet device if a process carried out in the process chamber involves plasma ignition. In particular, the plasma electrode can only be energized when it is positioned at a distance from the gas outlet surface.For plasma ignition, the distance between the top of the plasma electrode and the gas outlet surface can be, for example, between 1 and 75 mm. If only a process without the use of plasma in the process chamber is carried out, the plasma electrode preferably occupies a small distance, in particular... 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 especially smaller than 1 mm to the underside of the gas inlet element or a contact or contact position in which a top side of the plasma electrode is at least partially in contact with the underside of the gas inlet element facing the process chamber.

[0015] The plasma electrode can be heated by the susceptor, for example, by thermal radiation, conduction, induction heating, or by light heating or embedded heating elements, either in the plasma electrode itself or in the susceptor. The gas flowing from the gas inlet can be introduced into the process chamber through gas outlet openings formed by the plasma electrode. The surface temperature of the plasma electrode can be changed by varying the distance between the plate and the heated susceptor, the susceptor temperature, or the temperature of the heating device. Furthermore, the surface temperature of the plasma electrode can also be adjusted by plasma heating, whereby the power applied to the plasma electrode is varied.

[0016] To ignite a plasma in the process chamber, a counter electrode is required. The gas inlet, the housing wall surrounding the process chamber, and / or the susceptor can serve as the counter electrode. Alternatively, another component made of an electrically conductive material and located within the process chamber, but insulated from the plasma electrode, can be used. The counter electrodes can each be grounded.

[0017] A second embodiment of the invention can be a plasma electrode that is movable within the process chamber of a planetary reactor. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 The plasma electrode can be an annular plate or grid arrangement extending around the gas inlet element located in the center of the process chamber. Such an annular plate or ring arrangement can be positioned between a process chamber ceiling, which defines the upper boundary of the process chamber, and a susceptor, which defines the lower boundary of the process chamber. The plasma electrode can extend across the entire cross-section of the susceptor surrounding the gas inlet element. Lifting elements can also be provided to adjust the height of the plasma electrode within the process chamber.

[0018] The plasma electrode can preferably be arranged at a distance from the process chamber ceiling and the susceptor. In another operating position, the plasma electrode can be in contact with the process chamber ceiling. The process chamber ceiling, the susceptor, and the housing wall surrounding the process chamber can each function as a counter electrode.

[0019] The plasma electrode can be, for example, a plate made of graphite or coated graphite. For instance, the plasma electrode could be a graphite plate coated with SiC or TaC. It can also be made of a metal, such as tungsten (W), molybdenum (Mo), or stainless steel (SS). The plate can also be made of a conductive, refractory material, such as tungsten carbide (WC) or molybdenum steel.

[0020] The plasma generated in the process chamber by means of the plasma electrode can, for example, be used to produce a cleaning gas. A cleaning step can be carried out in the process chamber before or after a coating step, in which the gas fed into the process chamber is, for example, converted into cleaning radicals or ionic acid. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 The cleaning radicals are converted into reactive oxygen species. These cleaning radicals can be used to remove residues from the surface of the plasma electrode or other surfaces in the process chamber, for example, by a chemical reaction or ion bombardment. Suitable cleaning gases include, for example, halogen gases, reducing or oxidizing gases, gases suitable for ion bombardment, or mixtures or compounds thereof. The cleaning gases can be introduced into the process chamber along with a carrier gas. Volatile reaction products of the cleaning reactions can be removed from the process chamber with the carrier gas. For example, a gas mixture containing chlorine gas (Ch), oxygen (O2), and nitrogen (N2) can be used as the cleaning gas. For example, the gas mixture used for cleaning can contain 20% to 80% chlorine, 5% to 50% oxygen, and 0% to 50% nitrogen, in particular 60% chlorine, 8% oxygen, and 32% nitrogen. The cleaning gas can also contain chlorine chloride (BCI3).

[0021] The plasma electrode can be moved within the process chamber and precisely directed towards the surface to be cleaned. The distance between the plasma electrode and the surface to be cleaned is preferably adjusted such that the plasma interacts with the surface to remove any residues present. For example, to clean the surface of the susceptor or the surface of substrates mounted on the susceptor, the plate can be moved onto the susceptor.

[0022] The plasma generated by the movable plasma electrode in the process chamber can also be used to associate or dissociate other gases fed into the process chamber, such as precursor gases used in coating processes. In this way, the 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Activation, i.e., the chemical decomposition of the precursor organases, is carried out thermally and / or by means of plasma.

[0023] The invention further provides a method for cleaning surfaces in a device as previously described. The initial position can be one in which the plasma electrode touches or rests against the underside of the gas inlet element, or is arranged at a small distance, in particular less than 1 mm, from the underside. In a first step of the method according to the invention, the plasma electrode, which is in particular designed as a plate, can be moved to a first position at a distance, in particular more than 1 mm, from the gas outlet surface of the gas inlet element. In this first position, the plasma electrode preferably has a smaller distance to the gas outlet surface than to the bottom of the process chamber or to the susceptor.

[0024] In a second step, a first cleaning gas can be fed into the process chamber, which is activated by exposure to a plasma generated by the plasma electrode. The gas inlet and / or the wall and / or the floor of the process chamber can serve as the counter electrode. The plasma can form between the plasma electrode and the nearest electrode, in this example the gas inlet or the gas outlet of the gas inlet.

[0025] The voltage or power can be selectively increased until the plasma extends both above and below the plasma electrode, including the area between the plasma electrode and the susceptor. The plasma can completely surround the plasma electrode. Radicals generated by the plasma activation of the first purification gas can 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 In particular, residues on the underside of the gas inlet device facing the process chamber, as well as on the top and bottom of the plasma electrode, must be removed.

[0026] In a third step, the plasma electrode can be moved to a second spacing position, in which the plasma electrode has a greater distance to the gas outlet surface than in the first position. Alternatively, in the second spacing position, the process chamber floor or the susceptor can be moved towards the plasma electrode, so that the vertical distance of the plate to the process chamber floor or the susceptor is smaller than in the first spacing position, with the distance between the plate and the gas outlet surface corresponding to the first spacing.In the second spacing position, the distance between the plasma electrode and the gas outlet surface can preferably be greater than the distance between the plasma electrode and the susceptor. This allows a plasma generated in a fourth step to initially form between the plasma electrode and the susceptor. In this fourth step, the plasma primarily cleans the surface of the susceptor and the surface of the plate facing the susceptor. Due to the smaller distance between the plate and the heated susceptor compared to the first spacing position, the surface temperature of the plate is higher, thus facilitating the cleaning of the underside of the plate.

[0027] In the fourth step, the voltage or power can be increased to such an extent that the plasma also forms above the plate, i.e., in the area between the plate and the gas inlet. This allows the surface of the plate facing the gas inlet to be cleaned as well. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0028] In the fourth step, a second cleaning gas is introduced into the process chamber. This gas can be different from or the same as the first. The second cleaning gas can be activated by being exposed to a plasma generated by the plasma electrode, thus forming cleaning radicals that can be used for the previously described cleaning of the process chamber surfaces.

[0029] In the fourth step, the surfaces of substrates deposited from the susceptor can also be cleaned using the plasma. Layers deposited on the substrates, native oxides, or contaminants can also be partially or completely removed.

[0030] The cleaning steps described above can also be carried out in a different order; for example, the plasma electrode can first be moved to the second distance position and the susceptor or plasma electrode cleaned, and then moved to the first distance position to clean the gas inlet device.

[0031] In a further embodiment of the invention, a coating process can be carried out on substrates in the cleaned process chamber after the surfaces have been cleaned. For this purpose, the plasma electrode can be moved from the first or second spacing position to a contact position in which the upper side of the plasma electrode is at least partially in contact with the underside of the gas inlet element, i.e., the gas outlet surface, or is positioned at a small distance, in particular less than 1 mm, from the gas outlet surface. To coat the surface of substrates resting on the susceptor, 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 For cleaning, reducing gases, such as hydrogen (H₂) or ammonia (NH₃), halogen gases, such as Cl₂ or nitrogen trifluoride (NF₃), sulfur hexafluoride (SF₆) or tetrafluoromethane (CF₄), oxidizing gases, such as O₂, or gases suitable for ion bombardment, such as argon (Ar) or mixtures or compounds thereof, can be used as cleaning gases. The cleaning gases can optionally be introduced into the process chamber together with a carrier gas, such as N₂. After the substrate cleaning step, the plasma electrode can be moved back into its position. Following this, one or more process gases can be introduced into the process chamber. These gases, through thermal activation, form decomposition products that are deposited as a layer on the substrates resting on the susceptor.

[0032] In a further embodiment of the invention, the plasma electrode can be positioned at a distance from the gas outlet surface. Subsequently, one or more process gases can be fed into the process chamber, where they are decomposed by a plasma generated by the plasma electrode. The decomposition products are then deposited on the surface of the substrates, forming a coating. Here, the plasma activation of the gases introduced into the process chamber, carried out in the position at a distance, can be combined with the thermal activation of the gases without plasma activation, in which the plasma electrode, particularly in the contact position, rests against the underside of the gas inlet element.

[0033] The process includes not only the cleaning step described above, but also a process step preceding or following the cleaning step, in which one or more substrates are coated with a layer, in particular a semiconductor layer. This layer 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 SiC is particularly suitable, but so are the material pairings GaN and other II-VI, III-V, or IV-V materials. SiC can be deposited at a temperature of around 600°C (600°C ± 50°C). For the overall process, it is advantageous if the process chamber is kept at the same temperature during the deposition of the layer and the subsequent cleaning step, or if the temperature changes only minimally, for example, by a maximum of 20°C, 40°C, or 60°C. Loading and unloading the process chamber thus takes place at the same temperatures as the coating process. This eliminates the need for cooling or heating steps between the deposition and cleaning steps. Plasma cleaning is therefore preferably carried out without temperature changes.Temperature changes during loading or unloading are primarily due to natural heat dissipation caused by opening the process chamber. Therefore, using plasma makes it possible to perform a cleaning step at the same low temperatures after a process step carried out at relatively low process temperatures, removing residues from the process chamber walls.

[0034] During the deposition process, the plasma electrode should essentially be in contact with the ceiling of the process chamber. It is then only moved to a position at a distance for cleaning purposes.

[0035] Motor-driven lifting elements can be provided to move the plasma electrode from a contact position or near-contact position with the gas outlet surface to a position at a distance. The lifting element can, for example, be a threaded spindle that is rotationally fixed to the plasma electrode. With an electric motor 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 The rotary spindle nut allows the plasma electrode to be moved to different distance positions relative to the gas outlet surface.

[0036] The susceptor can be an electrically conductive component, for example, a component made of graphite. The susceptor can rest on a quartz cylinder or a quartz tube. In particular, the susceptor rests on a tube formed by an insulator. This tube can have axially extending bores through which electrical conductors protrude. These electrical conductors can, for example, be metal pins that connect the susceptor to an underlying, electrically conductive support. It is particularly intended that the support has elastically displaceable contact elements that interact with the electrical conductor. The contact element can have a spring that exerts force on the electrical conductor in the direction of the susceptor.

[0037] The electrical power for plasma generation is preferably transferred by means of a contact element extending through the gas inlet. For this purpose, the contact element can be an elongated conductor, in particular a metal rod. The conductor has a first end section which, in an electrically conductive connection, is in contact with a broad side of the plasma electrode facing the gas outlet surface. The metal rod can be rigidly connected to an insulating sheath. Alternatively, the metal rod can be inserted into an insulating guide sleeve. The guide sleeve can extend through the gas inlet. The metal rod can be displaced relative to the gas inlet in the same direction in which the plasma electrode can be displaced relative to the gas inlet. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0038] The conductor preferably has a second end section actuated by a spring element. The spring element can be a compression spring that exerts force on the contact element in the direction of the plasma electrode. When the plasma electrode is moved towards the gas inlet element, the spring element is compressed. The conductor then moves into or through the gas inlet element. The gas inlet element has a gas distribution chamber with an upper and a lower opening. A guide tube, optionally made of an insulating material, can extend between the upper and lower openings. The contact element extends through this guide tube. The upper section of the contact element can be connected to a head actuated by the spring element. The head can be displaceable in a vertical direction within a further sleeve, preferably made of an insulator.The spring element can also extend into this further sleeve, which can be supported upwards by a support element that is connected to a connecting element which can be connected to the plasma generator via a cable connection.

[0039] The lower opening of the gas inlet device can be located between one or more of the gas outlet openings. Brief description of the drawings

[0040] Exemplary embodiments of the invention are explained with reference to the accompanying drawings. These show: Fig. 1 schematically shows a cross-section of a process chamber 4 of a CVD reactor 3, with a gas inlet element 5 designed as a showerhead by way of example, wherein between the gas inlet element- 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 a plasma electrode 10, height-adjustable by means of lifting elements 17, is arranged between gan 5 and a susceptor 11 which limits the process chamber 4 downwards, and which has a distance Hl to the gas outlet surface 8, wherein the distance is almost 0, in any case less than 1 mm, Fig. 1a shows a representation according to Figure 1, however in an operating position in which the plasma electrode 10 has a greater distance to the gas outlet surface. Fig. 2 is a schematic representation according to Figure 1, wherein the distance Hl of the plasma electrode 10 to the gas outlet surface 8 is greater than the distance in the vertical position of the plasma electrode 10 shown in Figure 1 or Figure 1a, Fig. 3 schematically shows a cross-section of a further embodiment according to the invention of a CVD reactor 3 designed as a planetary reactor, wherein the plasma electrode 10 is designed as an annular plate which is arranged in a height-adjustable manner around the gas inlet element 5 located in the center of the process chamber 4 of the planetary reactor 3, Fig. 4 shows a schematic representation according to Figure 1, wherein only one lifting element 17, 18 is provided, which is attached to the ceiling of the housing 2 of the CVD reactor 3 and holds the plate 10 in the first spaced position, Fig. 5 is a schematic representation according to Figure 4, wherein the plate 10 is arranged in the second spacing position, in which 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 the distance Hl of the plasma electrode 10 to the gas outlet surface 8 is greater than in the first distance position shown in Figure 4, Fig. 6 shows a schematic representation according to Figure 3, wherein the plasma plate 10 is held by only one lifting element 17, 18 attached to the ceiling of the housing 2 of the CVD reactor 3, Fig. 7 shows another schematic representation, in which lifting elements 17 are designed as threaded rods, Fig. 8 shows a further embodiment of the invention, wherein the graphite susceptor 11 rests on a support element 37 which is an insulator and through which at least one conductor 39 extends, Fig. 9 shows the section along line IX-IX in Figure 8, Fig. 10 shows another embodiment of the invention, in which the process chamber 4 is permeated by the reactive gases in a horizontal direction. Fig. 11 shows the section along line XI-XI in Figure 11, Fig. 12 shows the section along line XII-XII in Figure 11, Fig. 13 shows a schematic embodiment of a contact element 19. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Description of the embodiments

[0041] The CVD reactor 3 shown in Figures 1, 1a, and 2 has a gas-tight housing 2 in which a process chamber 4 is arranged. The process chamber 4 is bounded above by a gas outlet surface 8 of a gas inlet device 5 and below by a susceptor 11. The height H2 of the process chamber 4 thus corresponds to the vertical distance between the gas outlet surface 8 and the susceptor 11. A plasma electrode 10, designed as a plate extending in the horizontal direction, is arranged between the gas outlet surface 8 of the gas inlet device 5 and the susceptor 11. The plasma electrode 10 is arranged at a distance H1 from the gas outlet surface 8 and extends parallel to the gas outlet surface 8.

[0042] The gas inlet element 5 is designed in an exemplary showerhead shape, so that the gas inlet element 5 is also referred to as a showerhead. The showerhead shown here is an example only. The showerhead can also have another design known from the prior art, for example as disclosed in DE 102021114868 A1. A gas outlet surface 8 extends along the underside of the gas inlet element 5, which has a plurality of gas outlet openings 6 through which gases fed into a gas distribution chamber 20 arranged above the gas outlet surface 8 can be introduced into the process chamber 4. A supply line 14 opens into the gas distribution chamber 20. Several supply lines can also be provided, each connected to a gas distribution chamber 20. Gases supplied from various gas sources 15, 21 can be fed into the gas distribution chamber 20 through the supply lines 14.Gases can be discharged from process chamber 4 via a gas outlet 27. The gases fed into process chamber 4 flow through gas outlet openings 7 arranged in the plasma electrode 10 into a lower section 4' of process chamber 4. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Gases can also flow laterally past the plasma electrode 10 into the lower section 4'.

[0043] The process chamber 4 is enclosed by a wall 12. The gas inlet element 5, the wall 12, and the susceptor 11 are grounded and function as counter electrodes to the plasma electrode 10. The counter electrodes 5, 11, 12 are each grounded by means of a grounding cable or grounding connection, which is electrically connected to the respective counter electrode 5, 11, 12 via a contact 23, 24, 25.

[0044] The plasma electrode 10 is electrically connected to a plasma generator 9 by means of a contact element 19, shown here by way of example as a spring. The plasma generator 9 can be used to apply a voltage to the plasma electrode 10. The plasma electrode 10 is configured to apply energy to a gaseous feedstock to generate a plasma. The contact element 19 is electrically insulated from the housing 2. The contact element 19 is guided through a channel formed by the gas inlet 5, and is also electrically insulated from the gas inlet 5, so that the plate 19 contacted by the contact element 19 is electrically insulated from the gas inlet 5 and the housing 2 of the CVD reactor.

[0045] The gas outlet surface 8 is cooled by a cooling element (not shown). The susceptor 11 is heated by a heating device 16. The temperature of the heating device 16 is preferably selected such that the temperature of the surfaces to be cleaned in the process chamber 4 is above the sublimation temperature and / or evaporation temperature of any intermediate products, such as metal chlorides, which are formed by the reaction of the cleaning gases or radicals with parasitic substances deposited on the surfaces. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Depositions are formed. The plasma electrode 10 is thermally and electrically decoupled from the cooled gas outlet surface 8 in the distance positions shown in Figures 1, 1a and 2, in which the plasma electrode 10 is arranged at a distance Hl from the gas outlet surface 8 of the gas inlet organ 5, and is heated by thermal conduction or by thermal radiation from the susceptor 11.

[0046] The plasma electrode 10 is designed here as a thin, circular plate and, according to the invention, is arranged in the process chamber 4 in a height-adjustable manner. The plate 10 is supported by retaining elements 18, which can be moved vertically by means of lifting elements 17. The plate 10 can also have a different design, for example as disclosed in DE 102021114868 A1.

[0047] Figure 1 shows the plasma electrode 10 as it is used during the deposition of layers within the process chamber. Here, the plasma electrode 10 forms a shielding plate that protects the gas outlet surface 8. The plasma electrode 10 is only slightly spaced from the gas outlet surface 8. Preferably, however, the plasma electrode 10 is positioned in contact with the gas outlet surface 8. During deposition, the plasma electrode 10 is generally not used to generate a plasma between the gas outlet surface 8 and the plasma electrode 10.

[0048] In Figure 1a, the plasma electrode 10, hereinafter also referred to as plate or plasma plate, is arranged in a first distance position in which the plasma plate 10 has a vertical distance Hl to the gas outlet surface 8. The plasma plate 10 is preferably moved into this position starting from the contact position shown in Figure 1a, and in this position the distance Hl is preferably less than 1 mm. In the first distance position, the distance Hl of the plasma electrode 10 to the gas outlet surface 8 is preferably greater than 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 1 mm. To ignite a plasma, gas is first introduced into the gap between the plasma plate 10 and the gas outlet surface 8 by means of the gas inlet device 5. This gas flows through the gas outlet openings 7 arranged in the plasma plate 10 into the lower section 4' of the process chamber 4. To ignite a plasma, the plasma electrode 10 is subjected to a voltage by the generator 9. The electric field thus generated leads to the ignition of the plasma. Since, in the first distance position of the plasma electrode 10 shown in Figure 1, the counter electrode closest to the plasma electrode 10 is the gas inlet device 5, the plasma initially forms in the area between the gas inlet device 5 and the plate 10. By increasing the voltage or power, the plasma propagation area can be further increased, so that the plasma can also propagate in the lower section 4' of the process chamber 4, i.e. between the plate 10 and the susceptor 11.

[0049] In the first position, the gas outlet surface 8 of the gas inlet organ 5 or the upper surface of the plasma electrode facing the gas outlet surface can be effectively cleaned by means of radicals generated during the plasma activation of the gas introduced into the process chamber 4. By increasing the voltage and the associated increased plasma propagation, not only the upper surface of the plasma electrode plate 10 facing the gas outlet surface 8 is cleaned, but also the underside of the plasma electrode plate 10 facing the susceptor 11. Thus, the entire plasma electrode plate 10 is cleaned.

[0050] In Figure 2, the plasma electrode 10 is arranged in a second position relative to the gas outlet surface 8, in which the distance Hl of the plasma electrode 10 to the gas outlet surface 8 is greater than the distance Hl that the 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 The plasma electrode plate 10 assumes the first distance position shown in Figure 1a. The distance H1 is greater than the distance H3 between the plate 10 and the susceptor 11, i.e., the height H3 of the lower section 4' of the process chamber 4, so that a plasma ignited in the process chamber 4 initially forms between the susceptor 11, which acts as a counter electrode, and the plate 10. This plasma can be used to clean the surface of the susceptor 11 and / or the plasma electrode plate 10 itself. The latter, due to the smaller distance H3 to the heated susceptor 11 compared to the first distance position, has a higher surface temperature, which facilitates the cleaning of the plate 10.

[0051] Alternatively, starting from the first spacing position, the process chamber floor 11 or the susceptor 11 can be moved towards the plate 10 in order to reduce the distance H3 between the plate 10 and the heated susceptor 11.

[0052] If one or more substrates 1 are arranged on the susceptor 11, the plasma electrode 10, positioned vertically away from the gas outlet surface 8, can also be used to generate a plasma for pre-cleaning the surface of the substrates 1 or for removing layers deposited on the substrates 1. Such a pre-cleaning step is often necessary to remove organic residues or native oxides that may be present on the substrates due to storage in ambient conditions. After pre-cleaning, the plasma electrode 10 is moved back into the contact position (not shown here), in which the plasma electrode 10 is at least partially in contact with the gas outlet surface 8 or is positioned at a distance Hl of, in particular, less than 1 mm from the gas outlet surface 8, in order to deposit layers onto the cleaned substrates 1 in a coating process. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0053] Furthermore, according to the invention, it is particularly provided to combine a coating process with a plasma-activated coating process. In a first step of such a process, the plasma electrode 10 is arranged in the contact position, i.e., in contact with or at a small distance Hl of less than 1 mm to the gas outlet surface 8. In a second step, the plasma electrode is then moved away from the gas outlet surface 8 to a distance position in which the distance Hl is greater than 1 mm in order to generate a plasma during the coating.

[0054] Figure 3 shows another embodiment in which several substrates 1 are arranged planetarily around the gas inlet element 5 located in the center of the process chamber 4, on which the susceptor 11 forms the lower boundary of the process chamber 4. These substrates are supported on bearing positions 31. A shaft 13, driven by a rotary drive 26 and fixedly connected to the susceptor 11, allows the susceptor 11, and thus the substrates 1 supported on the susceptor 11, to be rotated about a rotational axis D located in the center of the process chamber 4. Therefore, this is referred to as a "planetary reactor" in the following.

[0055] The process chamber 4 is bounded at the top by a process chamber ceiling 30. A height-adjustable plasma electrode 10 is arranged between the process chamber ceiling 30 and the susceptor 11, which is heated by the heating device 16. The plasma electrode 10 is designed as an annular plate that extends around the gas inlet element. The vertical distance Hl of the plate 10 to the gas outlet surface 8 of the gas inlet element 5 can be varied by means of the lifting elements 17.

[0056] The process chamber ceiling 30, the wall 12 surrounding the process chamber 4 and the susceptor 11 optionally function as a counter electrode for the 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Plasma electrode 10. The counter electrodes 11, 12, 30 are grounded, as in the embodiment shown in Figures 1 and 2.

[0057] The plasma electrode 10 is, by default, arranged in the contact position, in which the plasma electrode 10 rests against the gas outlet surface 8 of the gas inlet device 5 or has a distance of, in particular, less than 1 mm to the gas outlet surface 8. For a process that includes plasma excitation, the plasma electrode is moved to a position at a distance from the gas outlet surface 8, in which the plasma electrode plate has a distance Hl of, in particular, more than 1 mm to the gas outlet surface 8.

[0058] Depending on which surface in the process chamber 4 is to be cleaned, or depending on whether substrates 1 located on the susceptor 11 are to be cleaned or layers deposited on the substrates 1 are to be treated, the plate 10 can be moved either towards the process chamber ceiling 30 or towards the susceptor 11.

[0059] In the exemplary embodiments, the plasma electrode 10 can be in contact with the process chamber ceiling 30 or the gas outlet surface 8 at least partially when depositing layers in the process chamber 4 (see Figure 1).

[0060] The lifting element 17, 18 can be used as an electrical contact to the plasma electrode 10 or can be insulating. In the embodiments shown in Figures 1, 2, and 3, the plate 10 is supported by retaining elements 18, which can be moved vertically by means of lifting elements 17 arranged on the bottom of the housing 2 of the CVD reactor. More or fewer retaining elements 17, 18 can also be provided. As shown in Figures 1, 2, and 3, the plate 10 is supported by the retaining elements 18 at at least two points. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0061] Figures 4, 5, and 6 show further embodiments of the invention. Figures 4 and 5 essentially correspond to Figures 1 and 2, and Figure 6 to Figure 3, except that, unlike the embodiments shown in Figures 1, 2, and 3, only one lifting element 17, 18 is provided, which is also attached to the ceiling of the housing 2 of the CVD reactor 3 and holds the plasma plate 10 at only one support point. However, more than one lifting element 17, 18 can also be provided, holding the plate 10 at different support points. The support points can, for example, be arranged at opposite edge points of the plate 10.

[0062] Figure 7 shows a variant of the invention in which the lifting element 17 is formed by a threaded rod 19, which can, for example, be non-rotatably connected to the plasma electrode 10. The threaded rod 19 can also function as an electrode. To move the plasma electrode 10 vertically, a threaded nut 33, made, for example, of an insulating material, can be rotated. It can be driven by a gear 34, which is driven by a drive shaft 35 from an electric motor (not shown). In Figure 7, the contact element 19, designed as a threaded rod, extends through the gas inlet element 5.

[0063] Figure 8 shows a variant of the invention in which the susceptor 11 rests on a support element 37, which may be formed by an insulator. The support element 37 may be formed by a quartz tube whose diameter corresponds approximately to the diameter of the disk-shaped susceptor 11. A bore 49 extends from an upper edge to a lower edge in the support element 37. The lower edge of the support element 37 rests on a preferably electrically conductive carrier 38, which may be grounded. The electrically conductive susceptor 11 rests on the upper edge of the support element 37. A [missing information] extends within the bore 49. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 An electrical conductor 39, for example formed from a metal rod, has an upper section 19 that is electrically conductive and rests against the underside of the susceptor 11. The conductor 39 has a lower section that rests on a contact element 50. The contact element 50 can be displaceable vertically. It forms a plunger that is displaced vertically upwards by a spring element 51. The spring element 51 thus generates a spring force with which the conductor 39 rests against the underside of the susceptor 11. The spring element 51 can be a reversing-action compression spring.

[0064] Figures 10 to 12 show another embodiment of a CVD reactor. While the reactors described above have a gas outlet surrounding the susceptor 11, the reactor shown in Figure 10, which is also commonly referred to as a "horizontal reactor," has a linear gas flow from the gas inlet 5 towards a gas outlet 27. The cross-section shown in Figure 11 reveals two parallel side walls between which the flow extends. The substrate 1 is located between these side walls. A plasma electrode 10 is also shown, which can be moved vertically by means of threaded rods 32 or other lifting elements. A heating device 16 is located below the susceptor 11. Cooling channels 41 can extend in the housing wall above the plasma electrode 10. In this embodiment, the threaded rods 32 can be rotated.They are inserted into threaded holes 40 of the plasma plate 10.

[0065] Figure 13 shows, not to scale, an embodiment of a contact element with which electrical power can be supplied to the plasma electrode 10. The gas inlet element 5 has one or more gas distribution chambers 20, wherein the gas distribution chamber has an upper wall and a lower wall. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 The lower wall of the gas distribution chamber 20 forms the gas outlet surface 8 and has the gas outlet openings 6. Below the gas outlet surface 8 extends the plasma electrode 10, which has a back side against which a lower section 19' of a contact element 19 is supported. The contact element 19 is formed by a metallic rod that is firmly surrounded by an insulating sheath 48.

[0066] The contact element forms a guide tube 42, which is inserted into an opening in the upper wall of the gas distribution chamber 20 and into an opening in the lower wall of the gas distribution chamber. The contact element 19 extends through this guide tube 42. An upper section 19" of the contact element is supported by a slide 34, which is vertically displaceable in a cavity formed by an insulator 47. The slide 34 is acted upon by a spring element 44, which can be a compression spring. The spring element 44, in turn, is supported by a support element 45, which is electrically connected to a terminal element 46. The terminal element 46 can be connected to a plasma generator.

[0067] The spring element 44 preferably has a spring travel that is sufficiently large to allow the plasma electrode 10 to move from a contact position against the gas outlet surface 8 to a spaced position without the lower end section 19' losing its electrical contact with the plasma electrode 10. The contact element 19 can, for example, be completely immersed in the gas inlet element 5.

[0068] The spring element can be arranged in a housing that is located above the gas inlet element 5. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0069] The foregoing statements serve to explain the inventions covered by the application as a whole, which each independently further develop the prior art at least through the following combinations of features, whereby two, several or all of these combinations of features may also be combined, namely:

[0070] A device characterized in that the plasma electrode 10 is displaceable relative to the gas outlet surface 8 or the process chamber ceiling 3 in a direction transverse to the plane.

[0071] A device characterized in that a wall 12 surrounding the process chamber 4 and / or a susceptor 11 limiting the process chamber 4 downwards and / or the gas inlet element 5 and / or the process chamber ceiling 30 forms a grounded counter electrode.

[0072] A device characterized in that the plasma electrode 10 is height-adjustable by means of lifting elements 17.

[0073] A device characterized in that the plasma electrode 10 has a plurality of gas outlet openings 7.

[0074] A device characterized in that the plasma electrode 10, starting from a contact position in which the plasma electrode 10 is at least partially in contact with the gas outlet surface 8 of the gas inlet element 5 or the process chamber ceiling 30, or is arranged at a distance Hl to the gas outlet surface 8 or process chamber ceiling 30, which is in particular less than 1 mm, can be moved to one or more distance positions to the gas outlet surface 8 of the gas inlet element 5 for the purpose of generating the plasma. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 is, in which the distance Hl of the plasma electrode 10 to the gas outlet surface 8 is particularly greater than 1 mm.

[0075] A method for cleaning surfaces in a process chamber 4 of a device according to one of the preceding claims, comprising the following steps: positioning the plasma electrode 10 starting from a contact position or a near-contact position in which the plasma electrode 10 is at least partially in contact with the gas outlet surface 8 of the gas inlet element 5 or the process chamber ceiling 30, or is arranged at a distance Hl from the gas outlet surface 8 or the process chamber ceiling 30, which is in particular less than 1 mm, in a first distance position in which the distance Hl of the plasma electrode 10 to the gas outlet surface 8 is greater than in the contact position, in particular greater than 1 mm; introducing a first cleaning gas into the process chamber 4; plasma activation of the first cleaning gas by applying a voltage to the plasma electrode 10, so that radicals are formed;Removal of residues from the surfaces by reaction with the radicals, in particular from the gas outlet surface 8 of the gas inlet organ 5 and / or the process chamber ceiling 30 and / or the plasma electrode 10 and / or the susceptor 11.;

[0076] A method characterized by the following further steps: positioning the plasma electrode 10 in a second spacing position or relocating the susceptor 11, which delimits the process chamber 4 downwards, to a position in which the first plasma electrode 10 has a smaller distance H3 to the susceptor 11 compared to the first spacing position; introducing the first or a second cleaning gas into the process chamber 4; activating the first or second cleaning gas by a plasma generated by the plasma electrode 10, so that radicals are formed; 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 Removal of residues from the surfaces, in particular from the plasma electrode 10 and the susceptor 11.

[0077] A process characterized in that the first cleaning gas and / or the second cleaning gas is a halogen gas or a reducing or oxidizing gas or a gas suitable for ion bombardment, or mixtures or compounds thereof, which is optionally fed into the process chamber 4 together with a carrier gas.

[0078] A method characterized in that, in the first and / or second spacing position, residues on surfaces of one or more substrates 1 located on the process chamber floor 11 and / or optionally one or more layers deposited on the substrates 1 are removed with the generated radicals.

[0079] A method characterized in that a coating process is carried out in the process chamber 4 before or after cleaning, wherein the plasma electrode 10 is moved into a position in which a top surface of the plasma electrode 10 is at least partially in contact with the gas outlet surface 8 or the process chamber ceiling 30 or is arranged at a distance Hl of less than 1 mm from the gas outlet surface 8 or the process chamber ceiling 30, wherein one or more process gases are introduced into the process chamber 4, wherein decomposition products of the process gases are deposited as a layer on the substrates.

[0080] A method for depositing a layer on a substrate 1 in a process chamber 4 of a CVD reactor 3 according to any one of claims 1 to 5, wherein the process chamber 4 is enclosed downwards by a process chamber base- 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 the 11 is limited, on which one or more substrates 1 are arranged, comprising the following steps: positioning the plasma electrode 10, which bounds the process chamber 4 upwards, in a spaced position in which the plasma electrode 10 is arranged at an electrically insulating distance to the gas outlet surface 8; introducing one or more process gases into the process chamber 4, wherein the process gases are decomposed by a plasma generated by the plasma electrode 10, the decomposition products of the process gases growing on the surface of the substrates 1, forming a coating.

[0081] A method characterized in that the voltage or power acting on the plasma electrode 10 is increased in such a way that the plasma spreads both above and below the plasma electrode 10.

[0082] A method characterized in that the cleaning of the process chamber is carried out at a cleaning temperature which is insignificantly different from a process temperature at which a coating process is carried out in the process chamber 4 before or after the cleaning, wherein the process temperature and / or the cleaning temperature is in particular 600°C + / - 50°C, wherein the temperature inside the process chamber 4 changes only insignificantly during the loading or unloading of the process chamber 4 with substrates 1.

[0083] A device characterized in that the contact element 19 is displaceable in the displacement direction of the plasma electrode 10 and projects through an opening 6' of the gas outlet surface 8 and / or that the second end section 19" is subjected to force by a spring element 44 in the direction of the plasma electrode 10. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

[0084] A device characterized in that the contact element 19 is embedded in an insulating sheath 48 and / or that the contact element 19 is displaceable relative to a guide tube 42 which is fixedly connected to the gas inlet device 5.

[0085] A device characterized in that the spring element 44 is a compression spring and has a spring travel that is greater than the greatest distance of the plasma electrode 10 from the gas outlet surface 8, so that the contact element 19 can fully immerse itself in the gas inlet element 5.

[0086] A device for electrically connecting a susceptor 11 of a device according to one of the preceding claims with a carrier 38, wherein the carrier 38 carries a support element 37 made of an electrically insulating material and the support element 37 supporting the susceptor 11 has at least one bore 49 in which a conductor 39 electrically connecting the susceptor 11 with the carrier 38 extends, wherein the conductor 39 is supported on a contact element 50 which is acted upon by a spring element 51 in the direction of the susceptor 11.

[0087] All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of this application hereby incorporates in full the disclosure content of the associated / attached priority documents (copy of the earlier application), also for the purpose of including features of these documents in the claims of the present application. The dependent claims, even without the features of a referenced claim, characterize independent inventive developments of the prior art, in particular for the purpose of filing divisional applications on the basis of these claims. The features in 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 The invention specified in each claim may additionally include one or more of the features described above, in particular those identified by reference numerals and / or listed in the reference numeral list. The invention also relates to designs in which individual features mentioned in the preceding description are not implemented, especially insofar as they are recognizably unnecessary for the respective purpose or can be replaced by other technically equivalent means. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 List of reference symbols 1 Substrate 23 Contact 2 housings, 24 contacts 2a upper housing wall 25 contact 3 CVD reactor 26 rotary drive 4 Process chamber 27 Gas outlet 4' lower section of the Pro28 mass flow controller, combustion chamber 29 mass flow controller 5 Gas inlet device 30 Process chamber ceiling 6 Gas outlet opening 31 Substrate storage space 6' opening 32 threaded rod 7 Gas outlet 33 Nut 8 Gas outlet area 34 Gear 9 Plasma generator 35 Drive shaft 10 plasma electrode / plate 36 contact 11 Susceptor 37 Support element 12 walls, 38 beams 13 shaft 39 ladder 14 Supply line 40 Threaded hole 15 Gas source 41 Cooling channel 16 Heating device 42 Guide tube, casing 17 Lifting element 43 Slide 18 Holding element 44 Spring element 19 Contact element 45 Support element 19' first end section 46 connection element 19" second end section 47 insulator 20 Gas distribution chamber 48 insulating jacket, casing 21 Gas source telung 22 Contact 49 Bore 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 50 plungers, contact element 51 Spring element Hl gap height H2 Height Process Chamber H3 Height of the lower section 31384N1PCT drg / drag / g November 4, 2025 Ai Ltd 2024-01

Claims

39 Claims 1. Device for depositing a layer on a substrate (1) in a process chamber (4) arranged in a housing (2) of a CVD reactor (3), comprising a gas inlet element (5) for introducing gases into the process chamber (4), comprising a gas outlet surface (8) extending in a plane and having a plurality of gas outlet openings (6, 7) through which the gases can flow into the process chamber (4), comprising at least one plasma electrode (10) arranged in the process chamber (4) and capable of being supplied with an electrical voltage by a plasma generator (9), which is configured to generate a plasma, to supply energy to the gaseous starting material, characterized in that the plasma electrode (10) is displaceable relative to the gas outlet surface (8) or the process chamber ceiling (3) in a direction transverse to the plane.

2. Device according to one of the preceding claims, characterized in that a wall (12) surrounding the process chamber (4) and / or a susceptor (11) limiting the process chamber (4) downwards and / or the gas inlet element (5) and / or the process chamber ceiling (30) forms a grounded counter electrode.

3. Device according to one of the preceding claims, characterized in that the plasma electrode (10) is height-adjustable by means of lifting elements (17).

4. Device according to one of the preceding claims, characterized in that the plasma electrode (10) has a plurality of gas outlet openings (7). 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 40 5. Device according to one of the preceding claims, characterized in that the plasma electrode (10) can be moved from a contact position in which the plasma electrode (10) is at least partially in contact with the gas outlet surface (8) of the gas inlet element (5) or with the process chamber ceiling (30) or is arranged at a distance (Hl) to the gas outlet surface (8) or the process chamber ceiling (30), which is in particular less than 1 mm, into one or more distance positions to the gas outlet surface (8) of the gas inlet element (5) in which the distance (Hl) of the plasma electrode (10) to the gas outlet surface (8) is in particular greater than 1 mm.

6. A method for cleaning surfaces in a process chamber (4) of a device according to one of the preceding claims, comprising the following steps: Positioning the plasma electrode (10) starting from a contact position or a near-contact position in which the plasma electrode (10) is at least partially in contact with the gas outlet surface (8) of the gas inlet device (5) or is arranged at a distance (Hl) to the gas outlet surface (8) or the process chamber ceiling (30), which is in particular less than 1 mm, in a first distance position in which the distance (Hl) of the plasma electrode (10) to the gas outlet surface (8) or the process chamber ceiling (30) is greater than in the contact position, in particular greater than 1 mm; Introducing a first cleaning gas into the process chamber (4); Plasma activation of the first purification gas by applying a voltage to the plasma electrode (10) so that radicals are formed; Removal of residues from the surfaces by reaction with the radicals, in particular from the gas outlet surface (8) of the gas inlet device (5) and / or the process chamber ceiling (30) and / or the plasma electrode (10) and / or the susceptor (11). 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 41 7. The method according to claim 7, characterized by the following further steps: Positioning the plasma electrode (10) in a second spacing position or relocating the susceptor (11) which limits the process chamber (4) downwards into a position in which the first plasma electrode (10) has a smaller distance (H3) to the susceptor (11) compared to the first spacing position; Introducing the first or a second cleaning gas into the process chamber (4); Activation of the first or second purification gas by a plasma generated by the plasma electrode (10), so that radicals are formed; Removal of residues from the surfaces, in particular from the plasma electrode (10) and the susceptor (11).

8. Method according to claim 6 or 7, characterized in that the first cleaning gas and / or the second cleaning gas is a halogen gas or a reducing or oxidizing gas or a gas suitable for ion bombardment or mixtures or compounds thereof, which is optionally fed into the process chamber (4) together with a carrier gas.

9. Method according to claim 7 or 8, characterized in that in the first and / or second spacing position, residues on surfaces of one or more substrates (1) located on the process chamber floor (11) and / or optionally one or more layers deposited on the substrates (1) are removed with the generated radicals. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 10. Method according to one of claims 7, 8 or 9, characterized in that a coating process is carried out in the process chamber (4) before or after cleaning, wherein the plasma electrode (10) is moved into a position in which an upper surface of the plasma electrode (10) is at least partially in contact with the gas outlet surface (8) or the process chamber ceiling (30) or is arranged at a distance (Hl) of less than 1 mm from the gas outlet surface (8) or the process chamber ceiling (30), wherein one or more process gases are introduced into the process chamber (4), wherein decomposition products of the process gases are deposited as a layer on the substrates.

11. Method for depositing a layer on a substrate (1) in a process chamber (4) of a CVD reactor (3) according to any one of claims 1 to 5, wherein the process chamber (4) is bounded downwards by a process chamber floor (11) on which one or more substrates (1) are arranged, comprehensively the following steps: Positioning the plasma electrode (10) which defines the upper boundary of the process chamber (4) in a position where the plasma electrode (10) is arranged at an electrically insulating distance to the gas outlet surface (8) or the process chamber ceiling (30); Introducing one or more process gases into the process chamber (4), wherein the process gases are decomposed by a plasma generated by the plasma electrode (10), wherein the decomposition products of the process gases grow on the surface of the substrates (1) forming a coating. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 12. Method according to one of claims 7 to 11, characterized in that the voltage or power acting on the plasma electrode (10) is increased in such a way that the plasma spreads both above and below the plasma electrode (10).

13. Method according to one of claims 7 to 12, characterized in that the cleaning of the process chamber is carried out at a cleaning temperature which is insignificantly different from a process temperature at which a coating process is carried out in the process chamber (4) before or after the cleaning, wherein the process temperature and / or the cleaning temperature is in particular 600°C + / - 50°C, wherein the temperature inside the process chamber (4) changes only insignificantly during the loading or unloading of the process chamber (4) with substrates (1).

14. Device for transmitting electrical power to a plasma electrode (10) with an electrically conductive contact element (19) surrounded by an electrically insulating sheath (48, 42) and having a first end section (19') that is electrically connected to or in contact with the plasma electrode (10) and having a second end section (19") that is connected to a terminal element (46) which can be electrically connected to a plasma generator, characterized in that the contact element (19) is displaceable in the displacement direction of the plasma electrode (10) through an opening (6) Z ) protrudes through the gas outlet surface (8) and / or that the second end section (19") is subjected to force by a spring element (44) in the direction of the plasma electrode (10). 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01 44 15. Device according to claim 14, characterized in that the contact element (19) is embedded in an insulating sheath (48) and / or that the contact element (19) is displaceable relative to a guide tube (42) which is fixedly connected to the gas inlet element (5).

16. Device according to claim 14 or 15, characterized in that the spring element (44) is a compression spring and has a spring travel that is greater than the greatest distance of the plasma electrode (10) from the gas outlet surface (8), so that the contact element (19) can fully immerse itself in the gas inlet element (5).

17. Device for electrically connecting a susceptor (11) of a device according to one of the preceding claims with a carrier (38), wherein the carrier (38) carries a support element (37) made of an electrically insulating material and the support element (37) supporting the susceptor (11) has at least one bore (49) in which a conductor (39) electrically connecting the susceptor (11) with the carrier (38) extends, wherein the conductor (39) is supported on a contact element (50) which is acted upon by a spring element (51) in the direction of the susceptor (11).

18. Device or method characterized by one or more of the characterizing features of one of the preceding claims. 31384N1PCT drg / drag / g 4, November 2025 Ai Ltd 2024-01

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