Photon-assisted chemical etching of silicon carbide films from reaction chamber components.

Abstract

The present invention provides a method for etching a silicon carbide film from one or more components of a reaction chamber suitable for depositing a silicon carbide layer on a substrate. [Solution] The method comprises (i) providing a silicon carbide film on one or more components of a reaction chamber of a reactor for depositing silicon carbide, and (ii) performing at least one cycle of an etching process. The etching process comprises at least one cycle of UV photon-assisted chemical etching. The present invention further relates to a reactor adapted to perform the method.

Description

Technical Field

[0001] The present invention relates to the field of epitaxial deposition of semiconductor films on a substrate, and more particularly, to a method for performing photon-assisted chemical etching of silicon carbide from reactor components and a method adapted to perform the same, and to a reactor.

[0002] In addition, but not exclusively, the present invention relates to the field of deposition of silicon carbide films on semiconductor substrates in hot-wall, cross-flow, homoepitaxial or heteroepitaxial reactors.

Background Art

[0003] Semiconductor layers fabricated by epitaxial growth, also known as epitaxial layers, are formed by deposition within the reaction chamber of a reactor. The deposited material may be the same as the substrate or may include a different semiconductor having certain desired qualities. Epitaxial techniques are suitable for the manufacture of complex microprocessors and memory devices because they allow control of the crystal structure formed on the substrate and improvement of the surface characteristics of the epitaxial layer.

[0004] Typically, the reaction chamber is heated to a desired temperature prior to deposition, and then the temperature is maintained substantially constant throughout the deposition process.

[0005] In the case of an epitaxial reactor for the deposition of silicon carbide, the temperature within the cavity of the chamber can range from 1300 to 1700 °C. These temperatures can be reached in various ways, and the chamber may be of the "hot-wall" or "cool-wall" type. In a non-limiting example of the former, the walls of the reaction chamber as well as the enclosed cavity typically reach high deposition temperatures. These components can be effectively heated via induction means. In this case, the reaction chamber may comprise one or more structural components such as one or more walls made of a sensitive material such as graphite.

[0006] The reaction chamber may further include sensitivity functional components such as graphite substrate holders, rings, and upstream and downstream cover elements.

[0007] Both functional and structurally sensitive components may be provided with appropriate coatings to protect the chamber from contamination and extend its lifespan.

[0008] The reaction chamber may additionally include non-sensitive components, such as smooth polycrystalline SiC elements, which can be used for one or more structural components, such as side walls.

[0009] During the epitaxial deposition process, one or more semiconductor films grow on a rotating substrate in a controlled manner. However, undesirable semiconductor films may also grow simultaneously on other areas of the reaction chamber.

[0010] In fact, during the epitaxial deposition of polytypes of single-crystal silicon carbide substrates, such as 3C,4H, or 6H silicon carbide, users observe uncontrolled silicon carbide accumulation on both the structural and functional parts of the reaction chamber. It is worth noting that this undesirable silicon carbide accumulation is extremely difficult to remove due to the hardness of the material.

[0011] Silicon carbide accumulations may include polycrystalline and / or amorphous silicon carbide. Typically, this is a mixture of both polycrystalline and amorphous silicon carbide. The latter may constitute up to 20–60% of the total, as can be observed in XRD measurements, although the relative ratio may vary.

[0012] The parasitic phenomena described above are particularly relevant to hot-wall reactors and broadly affect the upstream end of the chamber (i.e., the part where the precursor gas enters the reaction chamber), as well as the elements surrounding the substrate or elements in contact with the substrate.

[0013] It is noteworthy that undesirable SiC accumulation can occur not only on the exposed surfaces of the reaction chamber but also on prophylactically coated components.

[0014] In practice, some or all components of the reaction chamber are typically provided with a TaC coating to protect the graphite surface during cleaning operations. Alternatively, a thin SiC coating is used to seal the exposed porous graphite surface and prevent chamber contamination. In this case, the SiC coating used on the graphite components is in a polycrystalline form and typically has a surface roughness of less than 6.3 μm Ra, more typically less than 1 μm Ra.

[0015] Parasitic deposition of SiC films on reaction chambers has often been observed to result in the rapid growth of cauliflower-like porous dendritic structures, which ultimately affect the quality of the deposited layer on the semiconductor substrate. These parasitic films have a non-uniform appearance with macroscopic irregularities.

[0016] While not limited to any particular theory, it is thought that geometric irregularities in the initial stages of SiC parasitic membrane formation act as seeds to promote fractal-like growth in a preferred direction, resulting in a highly heterogeneous membrane structure.

[0017] To prevent parasitic films from negatively impacting the deposition process, the reaction chamber undergoes frequent preventative maintenance (PM) operations, for example, every 100 μm to 2 mm of the total deposited epitaxial layer.

[0018] During PM, the machine is cooled and purged, and some or all of the affected parts are manually removed from the chamber for cleaning, disposal, and / or replacement.

[0019] PM operation negatively impacts reactor productivity, which in turn significantly affects the economics of the epitaxial deposition process.

[0020] In fact, PM operation can cause reactor downtime of up to 8-12 hours every few days of use.

[0021] Other techniques, such as in-situ or off-situ chemical etching processes, for removing parasitic deposits are known and used in Si reactors to remove undesirable Si deposits. These methods allow for more reproducible results than their mechanical cleaning. Furthermore, in-situ etching processes can be carried out without the need to open and access the reaction chamber, which is advantageous as it reduces reactor downtime and streamlines operation.

[0022] However, silicon carbide exhibits very different chemical and physical properties compared to silicon. Characterized by a Mohs hardness of 9–10, the material is resistant to chemical erosion without ultimately damaging the relevant reactor components and / or introducing potential contaminants into the chamber. In addition, the silicon and carbon components of SiC behave differently when exposed to chemical erosion.

[0023] Methods for etching SiC are disclosed in the art, but these methods typically discuss the removal of several top layers of ordered SiC from bulk SiC pieces, as described in US20140030892A1 and US20060001028A1. Chemical etching of SiC in these cases is performed when there are no underlying parts (potentially of different compositions) that could be damaged in the process. These processes typically remove only a few microns of SiC.

[0024] For example, the methods disclosed in Patent Documents 1 and 2 offer a wide range of process conditions. These address specific surface defects of the SiC pieces, respectively, such as warping of the single-crystal SiC substrate and surface cracks in the SiC substrate holder. These methods do not address the removal of disordered parasitic SiC deposits without damaging the affected reaction chamber components.

[0025] Therefore, it is desirable to provide a method for etching polycrystalline - amorphous SiC parasitic accumulation from related components of the reaction chamber without damaging said components.

[0026] Also, it is desirable to provide a method for etching polycrystalline / amorphous SiC parasitic accumulation that can be carried out directly within the reaction chamber, that is, without opening the reaction chamber and / or without extracting it from the reactor.

[0027] In addition, it is desirable to provide a new reactor adapted to carry out the above - described method. Further, it is desirable to provide a reactor configured to automatically carry out said method.

Prior Art Documents

Patent Documents

[0028]

Patent Document 1

Patent Document 2

Summary of the Invention

[0029] The summary of the present invention is provided to introduce some concepts in a simplified form. These concepts are further described in more detail in the detailed description of the exemplary embodiments of the present disclosure below. This summary is not intended to identify the main features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

Problems to be Solved by the Invention

[0030] The object of the present invention is to overcome the drawbacks of the prior art such as Patent Document 1 and Patent Document 2.

[0031] In particular, an object of the present invention is to provide a novel method for etching polycrystalline / amorphous SiC parasitic accumulations from reaction chamber components without damaging the components. A further object of the present invention is to provide a novel method for etching polycrystalline / amorphous SiC parasitic accumulations that can be carried out in situ.

[0032] A further object of the present invention is to provide a novel reactor adapted to perform the novel method described above in an optionally automated manner. [Means for solving the problem]

[0033] The primary objectives described above are achieved by the present invention as described in the appended claims, which constitute an integral part of this specification. [Brief explanation of the drawing]

[0034] [Figure 1] This is a block diagram schematically illustrating a method according to an embodiment of the present invention. [Figure 2] This is a block diagram schematically illustrating a method according to an embodiment of the present invention. [Figure 3] This is a block diagram schematically illustrating the method according to an embodiment of the present invention. [Figure 4] This is a block diagram that schematically shows the details of Figure 3. [Figure 5] A schematic side view of a reaction chamber according to one embodiment of the present invention is shown. [Figure 6] A schematic side view of a reaction chamber according to one embodiment of the present invention is shown. [Figure 7] A schematic cross-sectional view of a reaction chamber according to one embodiment of the present invention is shown. [Figure 8] A simplified schematic diagram of a reactor layout according to one embodiment of the present invention is provided. [Figure 9] This is a grayscale photograph of a parasitic silicon carbide film deposited on a spare graphite component in a hot-wall reaction chamber for silicon carbide deposition. [Modes for carrying out the invention]

[0035] The examples presented herein are not intended to represent the actual appearance of any particular material, structure, or device, but are merely idealized representations used to describe embodiments of the present disclosure.

[0036] While certain embodiments and examples are disclosed below, it will be understood by those skilled in the art that the scope of the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, as well as obvious modifications and equivalents thereof. Therefore, the scope of the invention disclosed is not intended to be limited by the specific embodiments disclosed below.

[0037] Here, similar reference numbers refer to figures that identify similar structural features or embodiments of the present disclosure.

[0038] In Figures 1 to 4, optional processes and subprocesses are distinguished from mandatory processes and subprocesses by using dashed lines instead of solid lines.

[0039] Figure 4 provides details of the execution of the etching process shown in Figure 3, in particular, details of how block 60 in Figure 3 operates in relation to its blocks 50 and 20.

[0040] In Figure 8, all digital signal connections are shown with dashed lines. Physical connections are shown with solid lines.

[0041] It will be understood that the elements in the figures are illustrated for simplification and clarity. In particular, some elements may be omitted or not drawn to scale. For example, the dimensions of some elements in the figures may be exaggerated relative to others to help improve understanding of the embodiments illustrated in this disclosure.

[0042] In a first aspect, the present invention relates to a method 1 for etching a SiC film from one or more components of a reaction chamber 100 of a reactor 1000, wherein the reactor is adapted for the deposition of a single-crystal SiC layer on a substrate.

[0043] Etching refers to chemical etching.

[0044] The reactor comprises at least one light source adapted to emit light in the range of 310–370 nm, i.e., its emission spectrum features one or more wavelengths in the UV region, but does not necessarily cover the entire spectral range.

[0045] Examples of light sources include UV lamps, LEDs, lasers, or combinations thereof.

[0046] Method 1 involves several steps or stages, which will be discussed below.

[0047] The first step (i) of the present invention is described in block 10 of Figures 1 to 3.

[0048] Step (i) is to provide a SiC film on one or more components of the reaction chamber of a reactor for depositing silicon carbide.

[0049] Step (ii) is to perform at least one cycle of the etching process described in block 30, i.e., the process for chemical cleaning / removal of the SiC parasitic deposits provided in step (i).

[0050] The etching process includes a series of steps or stages: (A) raising the reaction chamber to pre-set etching process conditions; (B) etching the silicon carbide film; and optionally (C) performing a cooling step.

[0051] Processes (A), (B), and (C) are described in blocks 40, 50, and 70 of Figures 2 and 3, respectively.

[0052] Specifically, process (A) includes the following sub-processes.

[0053] (A1) Raise the temperature of the reaction chamber to 800-1450°C, preferably 800-1100°C. (A2) Increase the pressure in the reaction chamber to 50-1000 mbar, preferably 150-700 mbar.

[0054] (A3) Optionally, an inert gas may be introduced into the reaction chamber, which may help to reach and maintain the desired temperature and pressure conditions.

[0055] All of the above sub-processes (A1) to (A3) (described in blocks 41, 42, and 43 in Figure 2, respectively) can be performed in any order, including simultaneously, whether mandatory or optional.

[0056] The pre-set etching process conditions for process (A) include, or consist of, the temperature and pressure conditions specified in sub-processes (A1) and (A2).

[0057] Step (A) is carried out by gradually adjusting the pressure and temperature conditions from a starting value to a desired process value, thereby protecting the reaction chamber from the undesirable effects of abrupt changes that could cause stress and damage to mechanical parts and / or a lack of uniformity of process conditions inside the reaction chamber.

[0058] Once the reaction chamber reaches the desired temperature and pressure settings, the actual etching of the SiC parasitic film can be carried out according to step (B).

[0059] Process (B) includes the following sub-processes:

[0060] (B1) Exposing the first reactive composition to the above light source (block 55), (B2) Delivering the first reactive composition into the reaction chamber (block 56).

[0061] The first reactive composition comprises one or more reactive gases, i.e., gases suitable for reacting with Si and / or C for etching purposes. In particular, the first reactive composition comprises at least a first reactive gas, such as a halogen molecule or halogen compound.

[0062] Preferably, the halogen molecule or halogen compound is selected with a purity of 99.990% or higher, and more preferably with a purity of 99.998% or higher.

[0063] The first reactive composition also includes a carrier gas, which is preferably an inert gas. For example, the carrier gas may be nitrogen, or preferably helium or argon to avoid contamination of the chamber. The carrier gas can advantageously be used to adjust and control the concentration and distribution of the reactive gas within the chamber.

[0064] Halogens or halogen compounds may be delivered into the reaction chamber in the form of molecules, radicals, and / or, but not limited to, ionized states such as a plasma state. In non-limiting examples, radicals and / or ions of the first reactive gas may be formed from molecular halogens or halogen compounds inside the reaction chamber by the temperature and pressure conditions inside the reaction chamber, and / or under an alternating RF electric field. Alternatively, radicals and / or ions of the first reactive gas may be formed just outside the reaction chamber under specific conditions of temperature, pressure, irradiation, and / or electric field.

[0065] It is worth noting that during sub-step (B2) of the etching process, due to the pressure and temperature conditions in the reaction chamber, halogen molecules or halogen compounds form radicals and / or ions, which erode the SiC film, thereby generating byproducts of the etching process. These byproducts are then removed from the reaction chamber.

[0066] Furthermore, it is noteworthy that the etching products for carbon etching are stable at temperatures below 1000°C. To improve the etching process, the first reactive gas can be made more reactive by enhancing its dissociation into radicals. In this way, the reaction can be carried out at lower temperatures, thus enabling a faster etching rate and carbon removal equivalent to silicon removal.

[0067] In sub-step (B1), the dissociation of the first reactive gas into radicals is facilitated before the first reactive composition enters the reaction chamber for sub-step (B2).

[0068] In one embodiment, the light source has at least one emission peak that all or partially overlaps with the absorption peak of the first reactive gas.

[0069] Thanks to the above sub-step (B1), the reaction chamber temperature can be raised and maintained at 800-1100°C during sub-step (A1). Without sub-step (B1), it might have been necessary to operate at a higher temperature. Lower temperatures allow for better stabilization of the carbon product. 、 This improves carbon etching and saves energy.

[0070] The inventors observed that the molar concentration of the first reactive gas in the carrier gas should be 15–40%. Surprisingly, by selecting a concentration within this range, it is possible to remove parasitic SiC deposits without damaging the associated coated / uncoated graphite components under the aforementioned temperature and pressure conditions. Removal of parasitic SiC deposits is not necessarily carried out until 100% removal is achieved. Advantageously, the deposits may be removed to a degree sufficient to regenerate appropriate operating conditions inside the reaction chamber, thereby extending the operating time between PM operations.

[0071] However, under the process conditions described herein, thanks to the UV photon-assisted approach, the method according to the present invention enables the effective removal of both carbon and Si from parasitic SiC deposits. The removal is sufficient to restart the deposition operation, thereby extending the operational life of the reaction chamber between consecutive PMs.

[0072] The SiC films mentioned above and below may be directly obtained, or can be obtained, as parasitic deposits of SiC on reaction chamber components during the epitaxial deposition process of the SiC layer on the rotating substrate inside the reaction chamber.

[0073] SiC films contain silicon carbide in polycrystalline and / or amorphous forms. Typically, this will consist of a mixture of both polycrystalline and amorphous SiC, for example, a mixture of 20-60% amorphous SiC and 40-80% polycrystalline SiC.

[0074] The amount of amorphous SiC in the film can be affected by extremely local and absolute variability due to the parasitic nature of the film.

[0075] Conversely, the SiC layers deposited on the substrate are typically single crystals. They are typically 3C, 4H, or 6H SiC polytypes, but are not limited to these. The number of layers may be one or more.

[0076] Parasitic SiC deposits are a well-known and undesirable by-product of single-crystal SiC layer deposition.

[0077] Parasitic SiC deposits occur on the surfaces of all components of the reaction chamber exposed to the SiC precursor gas flow, particularly at the upstream end of the chamber (i.e., where the precursor gas enters the reaction chamber), as well as on elements that are close to or in contact with the substrate. They do not occur on the rotating substrate when the reaction chamber is operating under normal conditions.

[0078] In particular, parasitic deposits occur on the removable and fixed components (covers, rings, walls) of the reaction chamber, whether stationary or rotating, as a result of exposure to SiC precursor gas during the epitaxial deposition process. These components are not made of silicon carbide, but are often made of materials with much lower hardness, such as graphite, and are optionally coated to improve the mechanical resistance of the reaction chamber or to prevent contamination.

[0079] Parasitic deposition of SiC is a phenomenon that affects hot-wall reaction chambers, though not limited to them. High temperatures on the walls and other parts of the reaction chamber promote this undesirable phenomenon.

[0080] For clarity, hereafter and thereafter, unless otherwise specified, the term “SiC film” shall be considered equivalent to “parasitic SiC film” or “parasitic SiC deposit,” and shall refer to SiC in polycrystalline and / or amorphous forms, and typically mixtures of both.

[0081] Furthermore, the term "film" in the expressions "SiC film" or "silicon carbide film" does not imply a two-dimensional, regular and / or ordered geometric shape. On the contrary, it refers to a non-uniform SiC coating that forms on one or more surfaces of a reaction chamber-affected component, as provided in Figure 9 and discussed further below, exhibiting a three-dimensional structure or a rough, textured surface. Parasitic silicon carbide films are an inevitable consequence of uncontrolled growth on reaction chamber components during epitaxial SiC layer deposition on a rotating substrate.

[0082] The terms “film” and “layer” are used here and below to distinguish undesirable parasitic SiC deposits (films) deposited on a substrate from desired, controlled, typically single-crystal SiC layers, respectively.

[0083] Generally, parasitic SiC films exhibit a non-uniform surface, for example, with obvious irregularities and variations in thickness. Surface non-uniformity is often clearly visible to the naked eye and usually includes visible macroscopic depressions and protrusions, which may be due to a caulifloric or fractal structure and dendritic growth processes, but is not always the case.

[0084] This phenomenon is particularly noticeable when the reaction chamber is operating for total single-crystal SiC deposition of 100-2000 μm (on the same substrate or on multiple substrates processed continuously without PM cycles), for example, when operating for total single-crystal SiC deposition of 100-800 μm, and affects the quality of the deposited layer.

[0085] In the above case, parasitic growth can be etched in a particularly satisfactory manner using this method.

[0086] Figure 9 shows a parasitic SiC film 121 on a component 120 of the reaction chamber, located on the bottom wall of the chamber 115. Component 120, which is an upstream cover, partially surrounds a receiving region 116 adapted to accommodate a 6-inch substrate. The parasitic SiC deposit appears brighter in grayscale photographs compared to other visible parts of the reaction chamber made of graphite. The parasitic deposit 121 covers the surface of component 120, exposed to the precursor gas, with a non-uniform, granular, rough film.

[0087] As reaction chamber components are exposed to the precursor gas flow, these irregular characteristics of the parasitic film become more pronounced.

[0088] Following the first step (i), the method of the present invention may include an optional purging step of the reaction chamber, as described in block 20. This step includes performing a purging process for 1 to 20 cycles, thereby removing any residues from other operations / processes performed in the reaction chamber.

[0089] During the purging process, the following sub-processes (blocks 21 and 22 in Figure 1) are executed sequentially, starting from one of them: • Sub-step to adjust the pressure in the reaction chamber to ≤1 mbar. • A sub-step in which an inert gas is introduced to bring the pressure inside the reaction chamber to 100-1000 mbar.

[0090] An optional cooling step (C) may be performed after step (B) and may include the following substeps: (C1) Cool the reaction chamber to a temperature preferably between 500 and 900°C, but lower than 1000°C (block 71). (C2) Flow a cooling gas to bring the inside of the reaction chamber to a pressure of 100-1000 mbar (block 72).

[0091] Sub-processes (C1) and (C2) can be performed in any order, including simultaneously.

[0092] Sub-step (C1) may be carried out by turning off the heating system and cooling the reaction chamber primarily by radiation. Sub-steps (C1) and (C2) may be carried out simultaneously to facilitate the cooling process.

[0093] The cooling gas used in sub-process (C2) may be any gas suitable for facilitating the cooling process of the chamber to an idle temperature of 500-900°C. Those skilled in the art can easily select the most appropriate gas, depending on budget and time constraints. Non-limiting examples of cooling gases include helium, nitrogen, hydrogen, and combinations thereof.

[0094] After step (B), and if present, before or after any step (C), it may be beneficial to optionally perform 1 to 20 cycles of the purging process described above (block 20) ​​to remove all traces of the reactive gas used, as well as any by-products of the etching process that may still be present in the chamber.

[0095] The cooling process (C) can, advantageously, be used to set favorable conditions for carrying out the aforementioned further optional purging processes. Conversely, the latter may help to achieve the effects of the cooling process (C) more efficiently, depending on the order in which they are performed.

[0096] In conclusion, any purging process may be performed as an additional step of the etching process after step (B) and before step (C), or after the etching process is complete and after both steps (B) and (C).

[0097] The method described above can be used for in-situ etching and in-situ etching of SiC films from one or more components of a reaction chamber, and has significant advantages.

[0098] For in-situ etching applications, the ability to chemically clean the reaction chamber after parasitic buildup and set it to suitable operating conditions without requiring (a) opening the reactor, (b) removing the reaction chamber, and (c) exposing its components to air for cleaning represents a significant improvement over current mechanical cleaning techniques.

[0099] Remarkably, despite the inherent and challenging properties of SiC, it is possible to effectively remove hard, disordered parasitic deposits up to several hundred microns in size without damaging the reaction chamber components.

[0100] The method described above addresses a long-standing industry need for a method to in-situ clean parasitic deposits from the reaction chamber of a SiC reactor.

[0101] In one embodiment, the flow rate of at least the first reactive gas is 5 to 15 slm (standard liters / min). Preferably, the flow rate of at least the first reactive gas is greater than 5 slm and less than 15 slm.

[0102] In one embodiment, the light source has an absorption peak of a first reactive gas and at least one emission peak that all or partially overlaps with it in the UV region.

[0103] If the first reactive gas has multiple absorption peaks in the UV region, it is advantageous to select a light source that overlaps, either entirely or partially, with the primary absorption peak.

[0104] For example, if the halogen gas is Cl2, it may be advantageous to select a light source having at least one emission peak at 310-370 nm, preferably 330-360 nm.

[0105] In one embodiment, the light source intensity is 310-370 nm, preferably 330-360 nm, and 5 × 10 16 ~5×10 17 photons / second / cm 2 It can be roughly equivalent to that.

[0106] In one embodiment, at least one light source is a mercury UV lamp. These lamps are typically constructed as tubes. They can be easily customized to optimize the irradiation of the reactive gas stream. Furthermore, mercury lamps can be advantageously doped with Fe, Co, Ga, and / or In (including Ga-In) to maximize emission in a desired spectral region, i.e., near the UV absorption peak of the first reactive gas.

[0107] The light source may have a power output of 2 to 8 kW.

[0108] In one embodiment, the reactor is provided with at least one optical device, such as a reflective element or concentrator (reflector or refractor), suitable for directing light from a light source onto the reactive gas flow.

[0109] The optical device described above may receive light coming directly and / or indirectly from a light source. In the latter case, it may receive, or be configured to receive, light emitted from the light source that has subsequently been reflected, refracted, diffracted, scattered, and / or diffused from the surrounding environment and the first reactive gas flow. The optical device may be advantageously oriented in such a way as to maximize the overlap between the redirected light and the reactive gas flow.

[0110] In one embodiment, the SiC film is obtained as a byproduct of one or more epitaxial deposition processes of single-crystal SiC layers on a rotating substrate, the process being carried out in a reaction chamber of a reactor, and the byproduct is formed on one or more components of the reaction chamber.

[0111] It is worth noting that the technical properties of SiC films imparted by parasitic accumulation processes can only be adequately defined from the perspective of the parasitic process itself. While the latter certainly imparts recognizable features such as film heterogeneity and unevenness, it can be argued that characterizing SiC films with respect to these features is unduly restrictive.

[0112] In one embodiment, step (i) of the method according to the present invention is carried out by performing one or more cycles of epitaxial deposition of a single-crystal SiC layer inside the reaction chamber of a reactor until a predetermined total thickness T of the layer deposited on one or more consecutive substrates is reached, where T is preferably 100 μm to 2 mm, more preferably 200 to 800 μm, and even more preferably 500 to 700 μm.

[0113] During this process, a parasitic SiC film with varying and non-uniform thickness is formed on one or more components of the reaction chamber. The SiC film thus obtained is said to have an "equivalent thickness" T, where T is the predetermined total thickness T mentioned above.

[0114] It is worth noting that the actual local thickness of the parasitic membrane may vary considerably within the reaction chamber and may differ from T on average.

[0115] It is worth noting that the peak of the parasitic membrane can be significantly higher than the thickness T due to the dendritic growth of the membrane.

[0116] In one embodiment, the etching process of the method according to the present invention is performed for 0.12 to 0.24 minutes per 1 μm of equivalent thickness T.

[0117] As mentioned above, in this art, the equivalent thickness of a parasitic film corresponds to the thickness of a single crystal layer deposited on one or more substrates during one or more sequential deposition processes (without PM). As the single crystal layer grows in an orderly manner on the substrate, the parasitic film grows on specific parts of the reaction chamber at varying heights. Therefore, it is more meaningful to refer to its equivalent thickness, which is a parameter set and controlled during reactor operation and readily measurable on the actual substrate after the deposition process.

[0118] The silicon carbide film of the present invention may exhibit a surface roughness of Ra greater than 6.3 μm, making it easily distinguishable from any SiC preventative coated component, the latter typically having a much lower surface roughness of Ra than 6.3 μm.

[0119] In one embodiment, when the first reactive gas is a halogen compound, the compound is a hydrogen halide.

[0120] In one embodiment, when the first reactive gas is a halogen compound, the halogen compound is not a metal halide, an interhalogen compound, an organic halogen compound, or a polyhalogen compound.

[0121] In one embodiment, the first reactive gas is selected from the group consisting of F2, ClF, ClF3, ClF5, Cl2, HCl, XeF2, XeF4, XeF6, XeO3, KrF2, Br2, I2, and HBr.

[0122] In one embodiment, the first reactive composition used in step (B) further comprises a second reactive gas.

[0123] In one embodiment, the second reactive gas is an oxidizing agent or a reducing agent.

[0124] A non-limiting example of a reducing agent is H2.

[0125] An oxidizing agent refers to an oxygen compound, oxygen molecule, or oxygen radical.

[0126] Hereafter, and in the following, examples of oxidizing agents that have been observed to function particularly well in the implementation of the present invention are N2O, NO, N2O2, O2, O3, and H2O2.

[0127] In one embodiment, the first reactive gas and the second reactive gas in the first reactive composition are, respectively, HCl and N2O, HCl and O3, HCl and H2O2, and HCl and O 2、 The group is selected from the following: Cl2 and O2, Cl2 and O3, Cl2 and H2O2, HCl and H2, and HCl and HF.

[0128] In one embodiment, step (B) includes the following sub-steps: (B3) Optionally, a sub-step of exposing the second reactive composition to at least one light source. (B4) A sub-step for delivering a second reactive composition into a reaction chamber, wherein the second reactive composition comprises one or more reactive gases and a carrier gas, the carrier gas being an inert gas, and the one or more reactive gases comprising at least a third reactive gas, the third reactive gas comprising a halogen, a halogen compound, or an oxidizing agent.

[0129] For example, the second reactive composition may include a halogen or halogen compound selected from the group consisting of F2, ClF, ClF3, ClF5, Cl2, HCl, XeF2, XeF4, XeF6, XeO3, KrF2, Br2, I2, and HBr.

[0130] For example, the second reactive composition may include an oxidizing agent selected from the group consisting of N2O, NO, N2O2, O2, O3, and H2O2.

[0131] For example, the second reactive composition may include a halogen or halogen compound and an oxidizing agent.

[0132] For example, the second reactive composition may include the following pairs: HCl and N2O, HCl and O3, HCl and H2O2, HCl and O 2、 This may include Cl2 and O2, Cl2 and O3, Cl2 and H2O2, HCl and H2, and HCl and HF.

[0133] In one embodiment, the first reactive composition and the second reactive composition include any of the following combinations, which are listed below as (first reactive composition) + (second reactive composition) for brevity. (F2) + (HCl and N2O), (F2) + (HCl and O3), (F2) + (HCl and H2O2), (F2) + (HCl and O2), (F2) + (Cl2 and O2), (F2) + (Cl2 and O3), (F2) + (Cl2 and H2O2), (F2) + (HCl and H2), (F2) + (HCl and HF), or (ClF) + (HCl and N2O), (ClF) + (HCl and O3), (ClF) + (HCl and H2O2), (ClF) + (HCl and O2), (ClF) + (Cl2 and O2), (ClF) + (C (12 and O3), (ClF) + (Cl2 and H2O2), (ClF) + (HCl and H2), (ClF) + (HCl and HF), (ClF3) + (HCl and N2O), (ClF3) + (HCl and O3), (ClF3) + (HCl and H2O2), (ClF3) + (HCl and O2), (ClF3) + (Cl2 and O2), (ClF3) + (Cl2 and O3), (ClF3) + (Cl2 and H2O2), (ClF3) + (HCl and H2), (ClF3) + (HCl and HF), (ClF5) + (HCl and N2O), (C (ClF5) + (HCl and O3), (ClF5) + (HCl and H2O2), (ClF5) + (HCl and O2), (ClF5) + (Cl2 and O2), (ClF5) + (Cl2 and O3), (ClF5) + (Cl2 and H2O2), (ClF5) + (HCl and H2), (ClF5) + (HCl and HF), (Cl2) + (HCl and N2O), (Cl2) + (HCl and O3), (Cl2) + (HCl and H2O2), (Cl2) + (HCl and O2), (Cl2) + (Cl2 and O2), (Cl2) + (Cl2 and O3 ),(Cl2)+(Cl2 and H2O2),(Cl2)+(HCl and H2),(Cl2)+(HCl and HF),(HCl)+(HCl and N2O),(HCl)+(HCl and O3),(HCl)+(HCl and H2O2),(HCl)+(HCl and O2),(HCl)+(Cl2 and O2),(HCl)+(Cl2 and O3),(HCl)+(Cl2 and H2O2),(HCl)+(HCl and H2),(HCl)+(HCl and HF),(XeF2)+(HCl and N2O),(XeF2)+(HCl and O3),(XeF2) + (HCl and H2O2), (XeF2) + (HCl and O2), (XeF2) + (Cl2 and O2), (XeF2) + (Cl2 and O3), (XeF2) + (Cl2 and H2O2), (XeF2) + (HCl and H2), (XeF2) + (HCl and HF), (XeF4) + (HCl and N2O), (XeF4) + (HCl and O3), (XeF4) + (HCl and H2O2), (XeF4) + (HCl and O2), (XeF4) + (Cl2 and O2), (XeF4) + (Cl2 and O3), (XeF4) +(Cl2 and H2O2),(XeF4)+(HCl and H2),(XeF4)+(HCl and HF),(XeF6)+(HCl and N2O),(XeF6)+(HCl and O3),(XeF6)+(HCl and H2O2),(XeF6)+(HCl and O2),(XeF6)+(Cl2 and O2),(XeF6)+(Cl2 and O3),(XeF6)+(Cl2 and H2O2),(XeF6)+(HCl and H2),(XeF6)+(HCl and HF),(XeO3)+(HCl and N2O),(XeO3)+(HCl (and O3), (XeO3) + (HCl and H2O2), (XeO3) + (HCl and O2), (XeO3) + (Cl2 and O2), (XeO3) + (Cl2 and O3), (XeO3) + (Cl2 and H2O2), (XeO3) + (HCl and H2), (XeO3) + (HCl and HF), (KrF2) + (HCl and N2O), (KrF2) + (HCl and O3), (KrF2) + (HCl and H2O2), (KrF2) + (HCl and O2), (KrF2) + (Cl2 and O2), (KrF2) + (Cl2 and O3) ,(KrF2)+(Cl2 and H2O2),(KrF2)+(HCl and H2),(KrF2)+(HCl and HF),(Br2)+(HCl and N2O),(Br2)+(HCl and O3),(Br2)+(HCl and H2O2),(Br2)+(HCl and O2),(Br2)+(Cl2 and O2),(Br2)+(Cl2 and O3),(Br2)+(Cl2 and H2O2),(Br2)+(HCl and H2),(Br2)+(HCl and HF),(I2)+(HCl and N2O),(I2)+(HCl and O3),(I2) + (HCl and H2O2), (I2) + (HCl and O2), (I2) + (Cl2 and O2), (I2) + (Cl2 and O3), (I2) + (Cl2 and H2O2), (I2) + (HCl and H2), (I2) + (HCl and HF), (HBr) + (HCl and N2O), (HBr) + (HCl and O3), (HBr) + (HCl and H2O2), (HBr) + (HCl and H2O2), (HBr) + (HCl and O2), (HBr) + (Cl2 and O2), (HBr) + (Cl2 and O3), (HBr) + (Cl2 and H2O2), (HBr )+(HCl and H2),(HBr)+(HCl and HF),(HCl and N2O)+(HCl and N2O),(HCl and N2O)+(HCl and N2O),(HCl and N2O)+(HCl and O3),(HCl and N2O)+(HCl and H2O2),(HCl and N2O)+(HCl and O2),(HCl and N2O)+(Cl2 and O2),(HCl and N2O)+(Cl2 and O3),(HCl and N2O)+(Cl2 and H2O2),(HCl and N2O)+(HCl and H2),(H (Cl and N2O) + (HCl and HF), (HCl and O3) + (HCl and N2O), (HCl and O3) + (HCl and O3), (HCl and O3) + (HCl and H2O2), (HCl and O3) + (HCl and O2), (HCl and O3) + (Cl2 and O2), (HCl and O3) + (Cl2 and O3), (HCl and O3) + (Cl2 and H2O2), (HCl and O3) + (HCl and H2), (HCl and O3) + (HCl and HF), (HCl and H2O2) + (HCl and N 2O), (HCl and H2O2) + (HCl and O3), (HCl and H2O2) + (HCl and H2O2), (HCl and H2O2) + (HCl and O2), (HCl and H2O2) + (Cl2 and O2), (HCl and H2O2) + (Cl2 and O3), (HCl and H2O2) + (Cl2 and H2O2), (HCl and H2O2) + (HCl and H2), (HCl and H2O2) + (HCl and HF), (HCl and O2) + (HCl and N2O), (HCl and O2) + (HCl and O3),(HCl and O2) + (HCl and H2O2), (HCl and O2) + (HCl and O2), (HCl and O2) + (Cl2 and O2), (HCl and O2) + (Cl2 and O3), (HCl and O2, ) + (Cl2 and H2O2), (HCl and O2) + (HCl and H2), (HCl and O2) + (HCl and HF), (Cl2 and O2) + (HCl and N2O), (Cl2 and O2) + (HCl and O3), (Cl2 and O2) + (HCl and H2O2), (Cl2 and O2) + (HCl and O2), (Cl2 and O2) + (Cl2 and O2), (Cl2 and O2) + (Cl2 and O3), (Cl2 and O2) + (Cl2 and H2O2), (Cl2 and O2) + (HCl and H2), (Cl2 (O2) + (HCl and HF), (Cl2 and O3) + (HCl and N2O), (Cl2 and O3) + (HCl and O3), (Cl2 and O3) + (HCl and H2O2), (Cl2 and O3) + (HCl and O2), (Cl2 and O3) + (Cl2 and O2), (Cl2 and O3) + (Cl2 and O3), (Cl2 and O3) + (Cl2 and H2O2), (Cl2 and O3) + (HCl and H2), (Cl2 and O3) + (HCl and HF), (Cl2 and H2O2) + (HCl and N2O), (Cl2 and H2O2) + (HCl and O3), (Cl2 and H2O2) + (HCl and H2O2), (Cl2 and H2O2) + (HCl and O2), (Cl2 and H2O2) + (Cl2 and O2), (Cl2 and H2O2) + (Cl2 and O3), (Cl2 and H2O2) + (Cl2 and H2O2), (Cl2 and H2O2) + (HCl and H2), (Cl2 and H2O2) + (HCl and H2), (HCl and H2) + (HCl and N2O), (HCl and H2) + (HCl and O3), (HCl and H2)+(HCl and H2O2), (HCl and H2)+(HCl and O2), (HCl and H2)+(Cl2 and O2), (HCl and H2)+(Cl2 and O3), (HCl and H2)+(Cl2 and H2O2), (HCl and H2)+(HCl and H2), (HCl and H2)+(HCl and HF), (HCl and HF)+(HCl and N2O), (HCl and HF)+(HCl and O3), (HCl and HF)+(HCl and H2O2), (HCl and HF)+(HCl and O2),(HCl and HF) + (Cl2 and O2), (HCl and HF) + (Cl2 and O3), (HCl and HF) + (Cl2 and H2O2), (HCl and HF) + (HCl and H2), or (HCl and HF) + (HCl and HF).

[0134] In one embodiment, the etching process of the method according to the present invention further includes a monitoring step (block 60), wherein the reaction chamber 100 comprises at least one monitoring system 500 adapted to monitor etching parameters indicating the endpoint of the etching process.

[0135] The monitoring process is performed at the end of process (B) and includes the following sub-processes: A sub-step for reading the preset target value (62) of the etching parameter and an arbitrarily preset tolerance range. Sub-step (61) to read the actual values ​​of etching parameters, A sub-step (63) to check whether the actual value has reached the target value within the arbitrarily predetermined tolerance range, A sub-process that repeats process (B) until the target value (arbitrarily within the preset tolerance range) is reached.

[0136] Once the target value is achieved, the monitoring process ends, and no further cycles of the etching process are performed.

[0137] The monitoring system may include a detector suitable for detecting the concentration of silicon and / or carbon in the by-product gas generated after each cycle of the etching process (B), such as a mass spectrometer.

[0138] Advantageously, this embodiment allows for monitoring the progress of the method according to the present invention.

[0139] For example, the monitoring process shown in Figure 3 may be performed according to the block diagram in Figure 4, but the sequences of blocks 61 and 62 may be replaced.

[0140] In one embodiment, the method according to the present invention is performed in situ to etch a silicon carbide film from one or more components of a reaction chamber. That is, the method is performed without opening the reactor when the reaction chamber is positioned inside the reactor. In this regard, the reaction chamber may be provided with at least one gas inlet and at least one gas outlet.

[0141] In this case, the light source is positioned upstream of the gas inlet. Thus, during step (B), the flow of the first reactive composition is exposed to UV photons emitted by the light source before entering the reaction chamber. The first reactive composition is then delivered into the reaction chamber through at least one gas inlet. Radicals or ions of the first reactive gas are generated (a) before entering the reaction chamber due to UV radiation, and (b) inside the reaction chamber due to the temperature and pressure conditions.

[0142] The chemical etching of the parasitic SiC film is carried out inside the reaction chamber, generating byproducts of the etching process. These byproducts may be discharged through at least one gas outlet.

[0143] Advantageously, in-situ cleaning of reaction chamber components allows for a significant reduction in PM time and operator exposure to the reaction chamber. Such exposure represents an EHS concern requiring thorough and time-consuming safety procedures.

[0144] Preferably, but not limited to, the reaction chamber in this embodiment is an epitaxial reaction chamber.

[0145] According to the embodiments described above, the present invention relates to a method for etching a SiC film in situ from one or more components of a reaction chamber in order to deposit a single-crystal silicon carbide layer on a substrate, wherein the reactor comprises at least one light source adapted to emit light corresponding to the absorption peak of a first reactive gas. The method is as follows: (i) Providing a silicon carbide film on one or more components of a reaction chamber of a reactor for depositing silicon carbide, wherein the reaction chamber comprises at least one gas inlet and at least one gas outlet; (ii) A step of performing at least one cycle of the etching process, wherein the etching process is (A) A step of raising the reaction chamber to the pre-set etching process conditions, (B) A process of performing an etching of a silicon carbide film, Includes.

[0146] Step (A) includes (A1) a sub-step of adjusting the temperature of the reaction chamber to 800 to 1450°C, preferably 800 to 1100°C, and (A2) a sub-step of adjusting the pressure of the reaction chamber to 50 to 1000 mbar, preferably 150 to 700 mbar.

[0147] Step (B) includes a sub-step of (B1) exposing a first reactive composition to a light source, and a sub-step of (B2) delivering the first reactive composition into a reaction chamber through a gas inlet, wherein the first reactive composition comprises one or more reactive gases and a carrier gas.

[0148] The carrier gas is an inert gas. One or more reactive gases include at least one first reactive gas which is a halogen or a halogen compound, and the molar concentration of the first reactive gas in the carrier gas is 15-40%.

[0149] Advantageously, the method according to the present invention does not affect the basic components of the reaction chamber, and can achieve a rate of 0.01 to 0.20 g / cm³ per hour. 2 This allows for the removal rate of the silicon carbide film to be achieved. This parameter may be measured during the calibration of the method by weighing the affected parts before and after deposition, as well as before and after etching.

[0150] In one embodiment, these components may include the upper and lower walls of the chamber, as well as (upstream and / or downstream) covers of the walls, as well as a ring, and other elements of the reaction chamber.

[0151] In one embodiment, the reaction chamber 100 of the method according to the present invention is of the hot-wall type, and one or more portions of the reaction chamber to be etched are made of graphite provided with a coating comprising or consisting thereof silicon carbide, pyrolytic graphite, pyrolytic carbon, polycrystalline diamond, single-crystal diamond, quartz, and / or boron nitride.

[0152] The silicon carbide coatings of the above embodiments typically exhibit much lower surface roughness than parasitic SiC films.

[0153] Typically, the coating has a surface roughness of less than 6.3 μm, preferably less than 1 μm, and usually exhibits a single-crystal or polycrystalline structure.

[0154] Parasitic SiC films have been observed to grow both on exposed graphite and on graphite covered with the aforementioned coating.

[0155] The method described above has been observed to work well in reaction chambers for silicon carbide deposition.

[0156] The reaction chamber may be of the type described in the international patent applications published as, for example, International Publication Nos. 2004 / 053187, International Publication Nos. 2004 / 053188, International Publication Nos. 2007 / 088420 and International Publication Nos. 2015 / 092525, but is not limited to these.

[0157] The reaction chamber may be, for example, of the type described in U.S. Patent Application No. 18 / 953993, but is not limited to that type.

[0158] These designs are affected by parasitic accumulation on graphite workpieces. Parasitic accumulation occurs on graphite components where preservation is critical.

[0159] The method according to the present invention is effective against parasitic SiC accumulation without damaging the underlying graphite components, thanks to the specific process conditions disclosed herein. Preferably, but not limited to, the method according to the present invention can be carried out when the reaction chamber is of the hot-wall, epitaxial, horizontal, and / or cross-flow type.

[0160] In any case, the present invention is not limited to a specific reaction chamber design.

[0161] As a non-limiting example, referring to Figures 5, 6, and 7, the reaction chamber 100 is configured for the epitaxial deposition of SiC and extends along the longitudinal axis x. The chamber may include inlets 155 and outlets 150 adapted to allow process gas, purge gas, cooling gas, and the first reactive composition to flow in and out of the reaction chamber and over the receiving region 116.

[0162] The receiving region is adapted to receive a substrate on the substrate holder. This may be a recess configured to position the substrate holder.

[0163] The receiving region may be adapted to allow the substrate holder to rotate during the SiC deposition process.

[0164] The chamber may further be equipped with appropriate injectors, liners, nozzles, and showerheads to facilitate the introduction and exhaust of any of the above-mentioned gases.

[0165] The chamber 100 may have a circular or elliptical cross-section in a cross-section yz perpendicular to the long axis x. The chamber may include an upper crescent 110 and a lower crescent 115, both made of graphite and separated by two transverse elements 117 made of polycrystalline SiC with a surface roughness of Ra of 0.5 to 1 μm.

[0166] The chamber may also include other components, such as a cover 120 used to protect the exposed upper surface of the bottom crescent 115 from SiC accumulation.

[0167] The reaction chamber 100 may further include several insulating elements, of which only element 180 is partially shown.

[0168] The reaction chamber 100 may further include a quartz enclosure 170. The quartz enclosure may be a double-walled quartz tube that is optionally cooled with a cooling fluid such as water.

[0169] The reaction chamber 100 may be surrounded by a heating system, such as an induction coil 200 wound around a quartz enclosure 170. The coil may be configured to heat the upper wall 110 and the lower wall 115 of the reaction chamber.

[0170] Many other variations of the above reaction chamber design can be used in carrying out the present invention.

[0171] In a second aspect, the present invention relates to a SiC reactor 1000 adapted to perform in-situ etching of a silicon carbide film deposited on one or more components of a reaction chamber 100, according to any embodiment of Method 1.

[0172] The reactor 1000 comprises at least one reaction chamber 100 for depositing a silicon carbide layer on a substrate, the reaction chamber comprising at least one gas inlet and at least one gas outlet.

[0173] Preferably, the reactor 1000 comprises 1 to 10 reaction chambers, and more preferably 1 to 4 reaction chambers.

[0174] The reactor is connected to, or can be connected to, sources of Si and C precursors (sources 1200, 1250). For example, the silicon precursor gas may be a chlorinated compound, preferably dichlorosilane, trichlorosilane, or tetrachlorosilane. The carbon precursor gas may be a hydrocarbon, particularly propane or ethylene or acetylene or methane. Other types of precursors may be used.

[0175] Other sources, such as sources for n-doping and p-doping, may be connected to or can be connected to the reactor. For example, the n source may be nitrogen, acetonitrile, pyrrole, ammonia, hydrazine, hydrogen cyanide, or methylamine.

[0176] The reactor is also connectable to, or connected to, a source of the first reactive composition through a gas inlet 155, so that the first reactive composition is delivered into the reaction chamber through the gas inlet.

[0177] The source of the first reactive composition may include a carrier gas (inert gas, preferably Ar or He) source 1100 and a first reactive gas source 1150. Other sources, such as a second or third reactive gas source, may also be present.

[0178] Generally, the term "source" refers to lines, cylinders, and / or containers for gas or liquid.

[0179] The reactor 1000 further comprises a heating system 200 adapted to heat the reaction chamber to a maximum temperature of 1700°C in order to carry out SiC deposition. Specifically, in the context of the present invention, the heating system 200 should be adapted to heat the reaction chamber to a temperature of 800 to 1450°C, preferably 800 to 1100°C, in order to carry out the etching process of the method according to the present invention. It is understood that the actual temperature inside the chamber may vary depending on the chamber design, the heating system, and the number of substrates being processed.

[0180] The heating system may be located outside the reaction chamber, as shown in Figures 5-8, but other configurations are also possible.

[0181] The reactor 1000 further comprises a light source 900 adapted to emit light in the range of 310 to 370 nm, preferably having an emission peak in the range of 330 to 360 nm.

[0182] The light source is preferably located upstream of the gas inlet.

[0183] The light source may be a UV laser, LED, or UV lamp. The light source is preferably a mercury UV lamp, optionally doped with Fe, Co, Ga, and / or In, for example, Ga-In.

[0184] The reactor 1000 may optionally include at least one optical device 950, such as a reflective element or concentrator, to direct light from a light source onto the first reactive composition before the first reactive composition is delivered into the reaction chamber.

[0185] The reactor 1000 further comprises a vacuum system 300 adapted to maintain a pressure of 1000 mbar or less in the reaction chamber, such as 100 to 1000 mbar. The vacuum system 300 may include at least one pump.

[0186] The pump is suitable for (a) depressurizing the reaction chamber 100 and / or (b) circulating exhaust gases (resulting from the deposition and etching processes, and / or cooling processes) from the reaction chamber through one or more gas outlets into the scrubber 400. The vacuum system may further include at least one valve, preferably a throttle valve located upstream of the vacuum pump.

[0187] Advantageously, the reactor described above is adapted to perform Method 1 according to the present invention, thereby achieving an improvement in reactor downtime due to PM.

[0188] In one embodiment, the gas inlet 155 of the reaction chamber 100 is preferably connected to a gas liner 156, and the light source 900 is preferably positioned upstream of the gas inlet and oriented toward the gas liner. The gas liner can advantageously be made of an intrinsically transparent material within a window of 310-370 nm. For example, the gas liner may be made of quartz.

[0189] In one embodiment, the reactor 1000 further comprises a processor 600, accessible memory, and an in-situ etching program.

[0190] The on-site etching program can be stored in memory accessible as a sequence of machine language instructions and can be adapted to perform steps (A) and (B) of the etching process of the method according to the present invention.

[0191] The processor 600 is configured, or can be configured, to execute an in-situ etching program, for example, by activating the control unit 700. These control units operate the sources 1100 and 1150 of the reactive gas mixture.

[0192] The control unit 700 may include a system of valves such as throttle valves, pumps, and circuits that can control the flow rate, timing, and absolute and relative amounts of the carrier gas and one or more reactive gases.

[0193] The gases used in the etching or SiC deposition process may be mixed before entering the reaction chamber 100. They may enter the reaction chamber in a single flow. Alternatively, they may enter the reaction chamber in multiple flows with different concentrations and / or flow rates, depending on the injection point and direction. In this sense, it is possible to use multiple inlets. Alternatively, it is possible to use a single inlet attached to a liner with separated regions to accommodate separate flows of gas.

[0194] The processor 600 may be configured, or can be configured, to control the vacuum system 300 via one or more valves, such as throttle valves, and circuits.

[0195] The reactor 1000 may optionally be equipped with a human-machine interface 800 to allow the end user to start the etching process, adjust the relevant parameters, and track its progress as needed.

[0196] In one embodiment, the reaction chamber 100 of the reactor 1000 is of the hot-wall type and optionally includes one or more components made of single-crystal or polycrystalline silicon carbide, pyrolytic graphite, pyrolytic carbon, polycrystalline diamond, single-crystal diamond, quartz, and / or graphite coated with boron nitride, having Ra irregularities of less than 6.3 μm.

[0197] The heating system 200 of the reactor 1000 may be an induction system.

[0198] The reactor may include a monitoring system 500, which is adapted to detect / monitor etching parameters indicating the endpoint of the etching process and is located between the downstream end of the reaction chamber 100 (after the gas outlet 150) and the scrubber 400 where the exhaust gas is processed.

[0199] The processor 600, if present, may be optionally configured or configurable to read and refine one or more signals from the monitoring system 500.

[0200] The reactor according to the present invention may be equipped with one or more detectors for detecting one or more reactive gases, the detectors including means for triggering an alarm or stop signal to ensure user safety.

[0201] It is understood that the reactor according to the present invention may include all other elements that are essential or desirable in a reactor, such as cabinets, pipes, actuators, circuits, valves, pumps, and power supply means.

[0202] The subject matter of this disclosure includes all novel and non-obvious combinations and partial combinations of the various processes, systems, and configurations disclosed herein, as well as all their equivalents.

Claims

1. A method for etching a silicon carbide film from one or more components of a reaction chamber of a reactor for depositing one or more silicon carbide layers on a substrate, The reactor comprises at least one light source adapted to emit light in the range of 310 to 370 nm, The aforementioned method, (i) A step of providing a silicon carbide film on one or more components of the reaction chamber, wherein the silicon carbide film comprises silicon carbide in a polycrystalline and / or amorphous form, (ii) A step of performing at least one cycle of an etching process, wherein the etching process is (A) A step of raising the reaction chamber to a preset etching process condition, (B) A step of performing the process which includes etching the silicon carbide film, Process (A) is, (A1) A sub-step of raising the temperature of the reaction chamber to 800 to 1450°C, (A2) A sub-step of raising the pressure of the reaction chamber to 100 to 1000 mbar, Process (B) is, (B1) A sub-step of exposing the first reactive composition to at least one light source, (B2) A sub-step of delivering the first reactive composition into the reaction chamber, wherein the first reactive composition comprises one or more reactive gases and a carrier gas, The one or more reactive gases include at least the first reactive gas, The first reactive gas is a halogen or a halogen compound, A method wherein the molar concentration of the first reactive gas in the carrier gas is 15 to 40%.

2. The method according to claim 1, wherein the at least one light source has at least one emission peak in the UV region that all or partially overlaps with the absorption peak of the first reactive gas.

3. The method according to claim 1 or 2, wherein the at least one light source is a mercury UV lamp doped with Fe, Co, Ga, and / or In.

4. The method according to claim 1 or 2, wherein the reactor comprises one or more reflective elements and / or concentrators adapted to direct the light from the at least one light source onto the first reactive composition.

5. The etching process further includes a cooling step (C) performed after step (B), the cooling step (C) is (C1) A sub-step of adjusting the temperature of the reaction chamber to a value of less than 1000°C, The method according to claim 1 or claim 2, comprising (C2) a sub-step of flowing a cooling gas into the reaction chamber at a pressure of 100 to 1000 mbar.

6. The process further includes the step of performing a purge process, wherein the purge process is A sub-step to adjust the pressure in the reaction chamber to 1 mbar or less, The process includes a sub-step of flowing an inert gas to bring the inside of the reaction chamber to a pressure of 100 to 1000 mbar, The method according to claim 1 or 2, wherein the purging process is performed 1 to 20 times before step (A) and / or after step (B).

7. The method according to claim 1 or claim 2, wherein the carrier gas is nitrogen, argon, or helium.

8. The method according to claim 1 or claim 2, wherein the flow rate of the first reactive gas is 5 to 15 slm.

9. The method according to claim 1 or 2, wherein the silicon carbide film is obtained as a byproduct of one or more epitaxial deposition processes of single-crystal silicon carbide layers on a rotating substrate performed in the reaction chamber of the reactor, and the byproduct is obtained on one or more components of the reaction chamber.

10. The method according to claim 1 or 2, wherein step (i) is carried out by performing one or more epitaxial deposition cycles of a single-crystal silicon carbide layer on the same or different substrates inside the reaction chamber of a reactor until a predetermined total deposition thickness T of the deposited single-crystal silicon carbide layer is reached, and T is between 100 μm and 2 mm.

11. The reaction chamber comprises at least one monitoring system adapted to monitor etching parameters indicating the endpoint of the etching process, The etching process is a monitoring process performed at the end of process (B), A sub-step for reading the preset target value of the etching parameter, A sub-step for measuring the actual value of the etching parameter, A sub-step of comparing the actual value of the etching parameter with the target value, The method according to claim 1 or 2, further comprising a monitoring step, which includes a sub-step of repeating step (B) until the actual value equals the target value.

12. The method according to claim 1 or 2, wherein one or more components of the reaction chamber to be etched are made of graphite coated with a coating comprising or consisting of polycrystalline diamond, single-crystal diamond, quartz, pyrolytic graphite, boron nitride, and / or silicon carbide.

13. The method according to claim 1 or 2, wherein the first reactive composition further comprises a second reactive gas.

14. The method according to claim 13, wherein the second reactive gas is an oxidizing agent.

15. Process (B) is, B3. A sub-step of exposing the second reactive composition to at least one light source, B4. A sub-step of delivering the second reactive composition into the reaction chamber, wherein the second reactive composition comprises one or more reactive gases and a carrier gas, The carrier gas is an inert gas, The one or more reactive gases include a third reactive gas, The method according to claim 1 or 2, wherein the third reactive gas comprises a halogen, a halogen compound, an oxidizing agent, or a combination thereof.

16. The oxidizing agent is N ２ O, NO, N ２ O ２ , O ２、 O ３ , and H ２ The method according to claim 14, selected from the group consisting of O.

17. The method according to claim 15, wherein the third reactive gas contains or consists of a halogen or halogen compound, and the molar concentration of the halogen or halogen compound in the carrier gas is 15 to 40%.

18. wherein the halogen or halogen compound is F ２ , ClF, ClF ３ , ClF ５ , Cl ２ , HCl, XeF ２ , XeF ４ , XeF ６ , XeO ３ , KrF ２ , Br ２ , I ２ The method according to claim 1 or claim 2, selected from the group consisting of and HBr.

19. A reactor for depositing one or more silicon carbide layers on a substrate, At least one reaction chamber, wherein the reaction chamber comprises at least one gas inlet and at least one gas outlet, A heating system adapted to heat the reaction chamber to a maximum temperature of 1700°C, A vacuum system adapted to maintain a pressure of 1000 mbar or less in the reaction chamber, A system comprising at least one light source adapted to emit light in the range of 310 to 370 nm, The reactor is configured to carry out the method of claim 1 or claim 2, The at least one gas inlet is connectable to the one or more sources of the reactive gas and the carrier gas, A reactor having at least one gas outlet configured to discharge by-products of the etching process.

20. The reactor according to claim 19, wherein the at least one gas inlet is connected to a gas liner made of quartz, and the at least one light source is positioned upstream of the gas inlet and oriented toward the gas liner.

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