Substrates Including Conformal Metal Carbide Coatings

Abstract

In a first aspect, the present disclosure provides a method for coating a substrate with a metal or transition metal carbide by thermal chemical vapor deposition, comprising the steps of: placing the substrate in a reaction chamber; 4 and supplying ethene and a carrier gas to a reaction chamber, wherein a process temperature in the reaction chamber is between about 900° C. and about 1050° C.

Description

[Technical field]

[0001] The present invention relates to the field of metal carbide coated substrates, more specifically to graphite substrates coated with a metal carbide coating characterized by a homogeneous layer thickness. [Background technology]

[0002] Coating a substrate with a metal carbide can be useful for several applications. For example, a metal carbide layer (such as a silicon carbide layer) can increase the hardness and / or mechanical strength of the substrate. In addition, the metal carbide layer can improve the chemical resistance of the coated substrate. Thus, adding a metal carbide coating to a substrate can increase its life time, for example by increasing wear and chemical resistance.

[0003] Due to its high temperature resistance (specifically, high melting point and thermal conductivity, and low coefficient of thermal expansion), graphite material can be used in many high temperature processes. In addition, graphite can be used as a susceptor. A susceptor can absorb electromagnetic energy and convert it to heat or re-emit the electromagnetic energy as infrared thermal radiation. Due to its function as a susceptor, relatively high chemical purity, and high temperature resistance, graphite can be used in the semiconductor industry as a wafer carrier (e.g., for chemical vapor deposition processes).

[0004] However, because graphite includes or is substantially composed of carbon, it may be susceptible to chemical attack. For example, in processes involving the use of hydrogen, graphite may be attacked by hydrogen. Moreover, graphite may still include contaminants that may be transferred in an undesirable manner to semiconductor wafers during high temperature processes. Furthermore, the surface of the graphite may release graphite particles that may cause damage to the wafer. For example, the surface of the graphite may release graphite particles when a wafer disposed therein is moved (e.g., rotated). Coatings may be added to the graphite surface to increase chemical resistance, mechanical resistance, and to seal contaminants and particles within the graphite. In particular, metal carbide coatings (such as, for example, silicon carbide coatings) may be used to increase the chemical resistance of graphite and seal its surface. However, known processes for adding metal carbide coatings to substrates present trade-offs. Alternatively, the growth rate of the metal carbide coating may be too slow to be economically viable or at least efficient, or the deposited metal carbide coating may not penetrate deep enough into the recesses, which may result in destruction of the substrate as chemical attack may occur within the recesses. Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure aims to address the above-mentioned problems in substrates that include metal carbide coatings. [Means for solving the problem]

[0006] process In a first aspect, the present disclosure provides a method for coating a substrate with a metal or transition metal carbide by thermal chemical vapor deposition, the method comprising: - placing a substrate in a reaction chamber; - supplying SiCl4, ethene, and a carrier gas to a reaction chamber; Including, The process temperature in the reaction chamber is between about 900°C and about 1050°C.

[0007] In some embodiments, the process temperature can be between about 925°C and about 1025°C, and more specifically, between about 950°C and about 1000°C.

[0008] In some embodiments, the method is carried out for a duration of between about 20 minutes and about 600 minutes, more particularly, between about 40 minutes and about 400 minutes, and particularly, between about 60 minutes and about 240 minutes.

[0009] In some embodiments, the total pressure in the reaction chamber can be between about 1 mbar and about 1085 mbar, more specifically, between about 5 mbar and about 100 mbar, and particularly, between about 7 mbar and about 15 mbar.

[0010] In some embodiments, SiCl4 and ethene can be provided as a precursor mixture, and the atomic ratio between silicon and carbon in the precursor mixture can be between about 0.7 and about 1.3, more specifically, between about 0.8 and about 1.2, and particularly, between about 0.9 and about 1.1.

[0011] In some embodiments, the method can include a first and a second step, the first step including supplying SiCl4 to the reaction chamber and the second step including supplying ethene to the reaction chamber, and in particular, the first step and the second step are alternated.

[0012] In some embodiments, the method can include a purging step between the first and second steps and / or between the second and first steps, the purging step including providing only carrier gas to the reaction.

[0013] In some embodiments, the duration of the first and / or second steps can be between about 1 second and about 5 seconds, more specifically between about 2.5 seconds and about 3.5 seconds, and / or the duration of the purge step can be between about 0.5 seconds and about 3 seconds, more specifically between about 0.8 seconds and about 1.2 seconds.

[0014] In some embodiments, the carrier gas additionally comprises HCl or Cl2, and more particularly HCl.

[0015] In some embodiments, the atomic ratio between chlorine and silicon in the precursor mixture can be between about 3.5:1 and about 5:1, more specifically between about 3.8:1 and about 4.7:1, and especially between about 4:1 and about 4.5:1.

[0016] In some embodiments, the carrier gas can include H2, and more specifically, the molar ratio between H2 and silicon in the combination of the carrier gas and precursor mixture can be between about 10:1 and about 100:1, even more specifically, between about 20:1 and about 70:1, and more specifically, between about 32:1 and about 50:1.

[0017] In some embodiments, the carrier gas may additionally comprise an inert gas, more specifically N2 and / or Ar, and more specifically N2.

[0018] In a third aspect, the present disclosure relates to a substrate comprising an outer surface and a recess disposed in the outer surface. The recess comprises a wall segment, and there is an edge disposed between the outer surface and the wall segment. The outer surface and the wall segment comprise a coating. Furthermore, the wall segment comprises a proximal section, and a distance between the edge and the proximal section is 500 μm. The outer surface comprises a first portion adjacent to the edge, and the wall segment comprises a second portion adjacent to the edge. The distance between the first portion and the edge and the distance between the second portion and the edge correspond to 110% of the thickness of the coating in the proximal section. Furthermore, the thickness of the coating in the first portion is between about 80% and about 120%, more particularly between about 90% and about 110%, and in particular between about 95% and about 105% of the thickness of the coating in the second portion.

[0019] In a second aspect, the present disclosure relates to a substrate, the substrate comprising an outer surface and a recess disposed in the outer surface. The recess further comprises a wall segment comprising a metal carbide coating, and there is an edge disposed between the outer surface and the wall segment. The wall segment comprises a proximal section and a distal section, the proximal section being positioned closer to the edge than the distal section. The distance between the proximal section and the distal section in a direction perpendicular to the outer surface is at least 100 μm. The metal carbide coating in the distal section has a thickness of at least 70% of the thickness of the metal carbide coating in the proximal section.

[0020] Coating Dimensions The thickness of the metal carbide coating in the proximal section can be between about 20 μm and about 300 μm, more specifically between about 50 μm and about 250 μm, and especially between about 80 μm and about 150 μm.

[0021] In some embodiments, the distance between the proximal and distal sections can be at least about 200 μm, more particularly at least about 400 μm, and especially at least about 600 μm.

[0022] In some embodiments, the distance between the proximal section and the edge can be at least about 200 μm, more particularly at least about 400 μm, and especially at least about 600 μm.

[0023] In some embodiments, the distance between the proximal section and the edge can be between about 200 μm and about 2 cm, more particularly between about 400 μm and about 1 cm, and particularly between about 600 μm and about 800 μm.

[0024] In some embodiments, the exterior surface may also include a metal carbide coating.

[0025] In some embodiments, the thickness of the metal carbide coating in the distal section can be between about 80% and about 200%, more specifically between about 90% and about 160%, and especially between about 95% and about 120%, of the thickness of the coating in the proximal section.

[0026] In some embodiments, the thickness of the metal carbide coating on the distal section can be between about 80% and about 200%, more specifically between about 90% and about 160%, and particularly between about 95% and about 120%, of the thickness of the metal carbide coating on the outer surface.

[0027] In some embodiments, the wall segment has a length between about 200 μm and about 50 cm, more particularly between about 5 mm and about 40 cm, and especially between about 5 cm and about 30 cm.

[0028] Plane Orientation In some embodiments, the wall segment and the outer surface can be disposed at an angle relative to one another, more specifically, the angle can be between about 45° and about 135°, particularly, the angle can be between about 70° and about 110°, and even more specifically, the angle can be between about 85° and about 95°.

[0029] In some embodiments, the wall segment and the exterior surface can be disposed substantially perpendicular or perpendicular to one another.

[0030] In some embodiments, the wall segment can have an opposing wall segment, and the distance between the wall segment and the opposing wall segment can be between about 250 μm and about 25000 μm, more particularly between about 500 μm and about 10000 μm, and particularly between about 1000 μm and about 7500 μm.

[0031] In some embodiments, the ratio between the length of a wall segment and the distance between the wall segment and an opposing wall segment can be at least 1:1, more particularly at least 5:1, even more particularly at least 10:1, and especially at least 20:1.

[0032] In some embodiments, the ratio between the length of a wall segment and the distance between the wall segment and an opposing wall segment can be between about 1:1 and about 100:1, more specifically between about 10:1 and about 75:1, and particularly between about 20:1 and about 50:1.

[0033] Edge In some embodiments, the metal carbide coating follows the contours of the underlying substrate, particularly, the metal carbide coating follows the contours of the underlying substrate at the edges.

[0034] In some embodiments, the change in thickness of the metal carbide coating along the edge can be less than 60%, more specifically less than 50%, and especially less than 45%.

[0035] In some embodiments, the outer surface can include a first portion adjacent to the edge and the wall segment can include a second portion adjacent to the edge, the distance between the first portion and the edge and the distance between the second portion and the edge corresponding to 110% of the thickness of the metal carbide coating in the proximal section, and the thickness of the metal carbide coating of the first portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and especially between about 95% and about 105% of the thickness of the metal carbide coating of the second portion.

[0036] In some embodiments, the thickness of the metal carbide coating in the first portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and particularly between about 95% and about 105%, of the thickness of the metal carbide coating in the proximal section.

[0037] In some embodiments, the thickness of the metal carbide coating in the second portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and particularly between about 95% and about 105%, of the thickness of the metal carbide coating in the proximal section.

[0038] In some embodiments, the edge can be an outer edge.

[0039] In some embodiments, the edge can be an inner edge.

[0040] Substrate Material In some embodiments, the substrate can comprise carbon, more specifically, the substrate can comprise at least about 90 wt% carbon, and more specifically, the substrate can comprise at least about 99 wt% carbon, based on the total weight of the substrate.

[0041] In some embodiments, the substrate can include graphite, more specifically, the substrate can include at least about 90 wt% graphite, and more specifically, the substrate can include at least about 99 wt% graphite, based on the total weight of the substrate.

[0042] In some embodiments, the substrate can comprise silicon, more specifically, the substrate can comprise at least about 90 wt% silicon, and more specifically, the substrate can comprise at least about 99 wt% silicon, based on the total weight of the substrate.

[0043] In some embodiments, the substrate can include isotropic graphite, more specifically, the substrate can include at least about 90 wt.% isotropic graphite, based on the total weight of the substrate, and more specifically, the substrate can include at least about 99 wt.% isotropic graphite.

[0044] In some embodiments, the substrate can include CFRC, and more specifically, the substrate can include at least about 90 wt.% isotropic graphite, based on the total weight of the substrate, and more specifically, the substrate can include at least about 99 wt.% CFRC.

[0045] In some embodiments, the substrate can be a cylinder, more particularly a cylinder having a diameter between about 5 cm and about 100 cm, and more particularly a cylinder having a diameter between about 15 cm and about 80 cm.

[0046] In some embodiments, the cylinder can have a thickness between about 1 mm and about 10 cm, more particularly between about 3 mm and about 5 cm, and particularly between about 5 mm and about 3 cm.

[0047] In some embodiments, the outer surface can include at least one disk-shaped pocket, the diameter of the recess can be between about 45 mm and about 700 mm, more particularly between about 100 mm and about 475 mm, and particularly between about 150 mm and about 300 mm, and / or the depth of the pocket can be between about 100 μm and about 2000 μm, more particularly between about 250 μm and about 1500 μm, and particularly between about 500 μm and about 1000 μm.

[0048] Coating Materials In some embodiments, the coating may include a metal carbide coating, which may include at least about 90 wt% metal carbide based on the total weight of the coating, more specifically, the metal carbide coating may include at least about 99 wt% metal carbide, and more specifically, the metal carbide coating may be composed of metal carbide.

[0049] In some embodiments, the metal carbide may include silicon carbide.

[0050] In some embodiments, the coating can include a plurality of carbide crystals.

[0051] In some embodiments, the metal carbide coating can be characterized by a full width at half maximum of the (111) peak between about 0.300° and about 1.000°, more specifically between about 0.350° and about 0.800°, and especially between about 0.400° and about 0.750°, as measured by XRD.

[0052] Gas Channel In some embodiments, the wall segment can include a first wall section and a second wall section, and the first and second wall sections can be disposed at an angle relative to one another.

[0053] In some embodiments, the second wall section extends orthogonally to the first wall section.

[0054] In some embodiments, the first wall section can have a length between about 0.1 cm and about 3 cm, more particularly between about 0.5 cm and about 2 cm, and particularly between about 1 cm and about 1.5 cm.

[0055] In some embodiments, the second wall section can have a length between about 1 cm and about 100 cm, more particularly between about 5 cm and about 75 cm, and particularly between about 25 cm and about 50 cm.

[0056] In some embodiments, the recess can have a first and a second opening, and the first opening can be disposed in the outer surface and the second opening can be disposed on the second outer surface of the substrate.

[0057] In some embodiments, the second edge can be disposed between the first wall section and the second wall section, the first wall section can include a third portion adjacent to the second edge, and the second wall section can include a fourth portion adjacent to the second edge, the distance between the third portion and the second edge and the distance between the fourth portion and the edge corresponds to 110% of the thickness of the metal carbide coating in the proximal section, and the thickness of the coating of the first portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and particularly between about 95% and about 105% of the thickness of the coating of the second portion. [Brief description of the drawings]

[0058] [Figure 1] 1 illustrates a thermal chemical vapor deposition process. [Diagram 2] The step coverage rate is shown. [Diagram 3] The growth rate is shown. [Figure 4] The step coverage rate is shown. [Diagram 5] The growth rate is shown. [Figure 6] The step coverage rate is shown. [Figure 7] The growth rate is shown. [Figure 8] Gas channels are shown. [Figure 9] 1 shows an SEM image of a substrate edge coated by the method according to the first embodiment. [Figure 10] 1 shows an SEM image of a substrate edge coated by a conventional method. [Figure 11] 1 shows a coating applied by a method according to a first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] The following provides a detailed description of the present disclosure. Terms or words used in the description and aspects of the present disclosure are not to be interpreted as having only common language or dictionary meanings, but as having their normal technical meanings as established in the relevant technical field, unless otherwise specifically defined in the following description. The detailed description will refer to specific embodiments to better illustrate the present disclosure, but it is understood that the disclosure presented is not limited to these specific embodiments.

[0060] Coatings, particularly metal carbide coatings, can be deposited on substrates by chemical vapor deposition. One variation of chemical vapor deposition is thermal chemical vapor deposition, where the reaction energy for coating deposition / formation is provided by high temperature. Typically, gaseous precursors are carried into the reaction chamber by a carrier gas. The combination of the carrier gas and the gaseous precursors can be referred to as the main gas flow. The main gas flow can also include H2.

[0061] FIG. 1 illustrates the processes in a thermal chemical vapor deposition process. Precursor molecules from the main gas flow and potentially H2 can diffuse into a boundary layer disposed between the main gas flow and the surface of the substrate. In the boundary layer, the precursors can decompose and / or react with H2 to form reactive species, which can then be transported to the substrate surface. At the substrate surface, the reactive species can adsorb to the surface. At the surface, the reactive species can further undergo changes due to surface reactions. Also, some of the reactive species (more specifically, volatile surface reaction products) can desorb from the surface, reducing the rate of coating formation.

[0062] Multiple reactive species can react to form a nucleus, which can expand by a step growth process and the edges of the nucleus can react with additional reactive species.

[0063] In general, it is expected that higher temperatures in chemical vapor deposition processes will result in higher coating growth rates because the rate of reactive species formation in the gas phase is increased.

[0064] In substrates that include features that extend from the outer surface into the bulk of the substrate (eg, recesses), the deposited coating is typically thicker on the outer surface than in the recesses.

[0065] It is believed that most chemical vapor deposition processes are limited by a trade-off between coating growth rate and penetration depth. If the reaction rate of the precursor is increased, the coating growth rate is increased. However, a higher reaction rate also results in a higher rate of depletion of the precursor in the gas stream that penetrates into the feature. As a result, with an increase in the coating deposition rate, the penetration depth into the feature and the coating uniformity along the feature are reduced.

[0066] Surprisingly, it has been found that a combination of silicon tetrachloride (SiCl4) and ethene (C2H4) as reactant gases in a thermal chemical vapor deposition process, when carried out at a temperature between about 900°C and about 1050°C, can result in a process with high growth rates, high penetration depths, and coating uniformity of the silicon carbide coating along the features.

[0067] process Thus, in a first aspect, the present disclosure provides a method for coating a substrate with a metal or transition metal carbide by thermal chemical vapor deposition, the method comprising: - placing a substrate in a reaction chamber; - supplying SiCl4, ethene, and a carrier gas to a reaction chamber; Including, The process temperature in the reaction chamber is between about 900°C and about 1050°C.

[0068] Thermal chemical vapor deposition processes involve a large number of chemical reactions, some of which are not understood in all details. However, without wishing to be bound by theory, it is believed that during the surface reaction, chlorine reversibly adsorbs to the surface at the reaction sites of the substrate. The adsorbed chlorine temporarily blocks the reaction sites. The chlorine in the process is a reaction product of silicon carbide deposition, and therefore the rate of chlorine generation is dependent on the deposition rate. Since the rate of chlorine generation depends on the rate at which reactive species adsorb to the surface, the reaction can be considered as self-limiting. Thus, the reaction sites can form a bottleneck, which can result in the reaction kinetics of the coating deposition reaction approaching a zero-order reaction as long as the concentration of chlorine is above a certain threshold and the temperature is within a certain range. A zero-order reaction is a chemical reaction whose rate does not change with increasing or decreasing the concentration of the reactants (e.g., precursors).

[0069] Without wishing to be bound by theory, it is possible that diffusion is the limiting process for the precursor to enter the recesses. Diffusion is a time-dependent process, similar to the coating deposition process. As a result, it is generally expected that the concentration of the precursor from the main gas flow will be depleted on its way into the recesses. Since reaction rates are concentration-dependent, except for zero-order reactions, a lower deposition rate, and therefore a lower coating thickness, is generally expected in the recesses than at the outer surface in a chemical vapor deposition process. Similarly, a smaller coating thickness is expected at locations in the recesses closer to the outer surface compared to those farther away from the outer surface.

[0070] As the reaction kinetics approaches zero order, this can increase the penetration depth into the feature and especially the coating thickness uniformity. Due to blocking of reaction sites, reactants do not react primarily at the entrance into the feature, as would likely happen in conventional processes with high deposition rates. Thus, the penetration depth and especially the coating thickness uniformity can be increased.

[0071] A commonly used precursor for depositing silicon carbide films on a substrate is methyltrichlorosilane. Methylchlorosilane (MTS) has a silicon to chlorine ratio of 1:3, while SiCl4 has a ratio of 1:4. Considering the above theory, it is expected that the growth rate of SiCl4 will be reduced compared to MTS. As can be seen in Figure 3, the growth rate of SiCl4 unexpectedly exceeds that of MTS in the temperature range between 900 ° C and about 1050 ° C.

[0072] Furthermore, the use of SiCl4 results in improved step coverage compared to MTS, as presented in Figures 2 and 4. The step coverage was calculated by the following formula for a recess (specifically a trench) with a depth of 1000 μm and a width of 300 μm:

[0073] Step coverage rate = t bottom / t top

[0074] The improved uniformity of the coating can also be seen in Figures 10 and 11. Figure 10 shows a coating applied by a conventional process, while Figure 11 shows a coating applied by the method according to the first embodiment.

[0075] Further results will be discussed in the experimental section.

[0076] In some embodiments, the process temperature can be between about 925° C. and about 1025° C., and more specifically, between about 950° C. and about 1000° C. As can be seen in Figures 2 and 3, these temperatures can result in optimal step coverage and growth rates.

[0077] In some embodiments, the method is carried out for a duration of between about 20 minutes and about 600 minutes, more particularly, for a duration of between about 40 minutes and about 400 minutes, and particularly, for a duration of between about 60 minutes and about 240 minutes.

[0078] In some embodiments, the total pressure in the reaction chamber can be between about 1 mbar and about 1085 mbar, more specifically, between about 5 mbar and about 100 mbar, and particularly, between about 7 mbar and about 15 mbar.

[0079] In some embodiments, SiCl4 and ethene can be provided as a precursor mixture, and the atomic ratio between silicon and carbon in the precursor mixture can be between about 0.7 and about 1.3, more specifically between about 0.8 and about 1.2, and more specifically between about 0.9 and about 1.1. The silicon to carbon ratio can be adjusted, for example, by adding MTS into the precursor gas mixture to adjust the properties of the coating.

[0080] In some embodiments, the precursor mixture comprises less than 30 mol%, more specifically less than 20 mol%, and even more specifically less than 10 mol%, particularly substantially free or no other carbon source other than ethene, based on the total precursor mixture. In some embodiments, the precursor mixture comprises less than 30 mol%, more specifically less than 20 mol%, and even more specifically less than 10 mol%, particularly substantially free or no other silicon source other than SiCl4.

[0081] In some embodiments, the method can include a first and a second step, the first step including supplying SiCl4 to the reaction chamber and the second step including supplying ethene to the reaction chamber, and in particular, the first step and the second step are alternated.

[0082] In some embodiments, the method can include a purging step between the first and second steps and / or between the second and first steps, the purging step including providing only carrier gas to the reaction.

[0083] Providing SiCl4 in a first step and ethene in a second step can result in an increased conformal metal carbide coating, especially when only a carrier gas is provided in a purge step between the first and second steps. Without wishing to be bound by theory, SiCl4 can diffuse into the recesses as it is provided in the first step and thereafter. Since diffusion is time- and concentration-dependent, it is expected that the concentration of SiCl4 will be higher in parts of the recess closer to the edge and / or outer surface when a carrier gas is provided in the purge step. However, the purge step can remove more SiCl4 near the edge and / or outer surface compared to deeper in the recess. Still, without wishing to be bound by theory, this can equalize the concentration of SiCl4 along the depth of the recess, or even result in a higher concentration of SiCl4 deeper in the recess compared to closer to the edge / outer surface. When ethene is subsequently provided, the reaction rate can be concentration-dependent. As a result, the reaction rate along the depth of the recess may be equalized or even higher deeper into the recess compared to near the edge / outer surface. A subsequent purge step can again equalize the concentration of SiCl4 and ethene along the depth of the recess or even result in a higher concentration in the recess, allowing for a more homogenous reaction rate along the recess or an increased reaction rate deeper into the recess. The first step, the second step, and the purge step can be repeated. Furthermore, the method can start with the second step.

[0084] In some embodiments, the duration of the first and / or second steps can be between about 1 second and about 5 seconds, more specifically between about 2.5 seconds and about 3.5 seconds, and / or the duration of the purge step can be between about 0.5 seconds and about 3 seconds, more specifically between about 0.8 seconds and about 1.2 seconds.

[0085] In some embodiments, the carrier gas additionally comprises HCl. Surprisingly, it has been found that the addition of HCl can result in increased step coverage. However, the increased proportion may reduce the growth rate of the coating. In some embodiments, the carrier gas additionally comprises Cl2. Cl2 can also result in increased step coverage due to blocking of reactive sites.

[0086] In some embodiments, the atomic ratio between chlorine and silicon can be between about 3.5:1 and about 5:1 in the precursor mixture, more specifically between about 3.8:1 and about 4.7:1, and more specifically between about 4:1 and about 4.5:1. For example, by adding HCl, an increased proportion of chlorine can result in increased step coverage. However, the increased proportion may reduce the growth rate of the coating.

[0087] In some embodiments, the carrier gas can include H2, and more specifically, the molar ratio between H2 and silicon in the combination of the carrier gas and precursor mixture can be between about 10:1 and about 100:1, even more specifically, between about 20:1 and about 70:1, and more specifically, between about 32:1 and about 50:1.

[0088] In some embodiments, the carrier gas may additionally comprise an inert gas, more specifically, N2 and / or Ar, and more specifically, N2.

[0089] The substrate to be used in the coating method In the following, embodiments of the substrate to be used in the coating method of the first aspect are described.

[0090] In some embodiments, the substrate (placed into the reaction chamber) can include an outer surface and a recess disposed in the outer surface. Additionally, the recess can include a wall segment, with an edge disposed between the outer surface and the wall segment. The wall segment can include a proximal section and a distal section, with the proximal section positioned closer to the edge than the distal section. The distance between the proximal section and the distal section in a direction perpendicular to the outer surface can be at least 100 μm.

[0091] In some embodiments, the distance between the proximal and distal sections can be at least about 200 μm, more particularly at least about 400 μm, and especially at least about 600 μm.

[0092] In some embodiments, the distance between the proximal section and the edge can be at least about 200 μm, more particularly at least about 400 μm, and especially at least about 600 μm.

[0093] In some embodiments, the distance between the proximal section and the edge can be between about 200 μm and about 2 cm, more particularly between about 400 μm and about 1 cm, and particularly between about 600 μm and about 800 μm.

[0094] In some embodiments, the wall segments can have a length between about 200 μm and about 50 cm, more particularly between about 5 mm and about 40 cm, and particularly between about 5 cm and about 30 cm.

[0095] In some embodiments, the wall segment and the outer surface can be disposed at an angle relative to one another, more specifically, the angle can be between about 45° and about 135°, particularly, the angle can be between about 70° and about 110°, and even more specifically, the angle can be between about 85° and about 95°.

[0096] In some embodiments, the wall segment and the exterior surface can be disposed substantially perpendicular or perpendicular to one another.

[0097] In some embodiments, the wall segment can have an opposing wall segment, and the distance between the wall segment and the opposing wall segment can be between about 250 μm and about 25000 μm, more particularly between about 500 μm and about 10000 μm, and particularly between about 1000 μm and about 7500 μm.

[0098] In some embodiments, the ratio between the length of a wall segment and the distance between the wall segment and an opposing wall segment can be at least 1:1, more particularly at least 5:1, even more particularly at least 10:1, and especially at least 20:1.

[0099] In some embodiments, the ratio between the length of a wall segment and the distance between the wall segment and an opposing wall segment can be between about 1:1 and about 100:1, more particularly between about 10:1 and about 75:1, and especially between about 20:1 and about 50:1.

[0100] In some embodiments, the edge can be an outer edge.

[0101] In some embodiments, the edge can be an inner edge.

[0102] In some embodiments, the substrate can comprise carbon, more specifically, the substrate can comprise at least about 90 wt% carbon, and more specifically, the substrate can comprise at least about 99 wt% carbon, based on the total weight of the substrate.

[0103] In some embodiments, the substrate can include graphite, more specifically, the substrate can include at least about 90 wt% graphite, and more specifically, the substrate can include at least about 99 wt% graphite, based on the total weight of the substrate.

[0104] In some embodiments, the substrate can comprise silicon, more specifically, the substrate can comprise at least about 90 wt% silicon, and more specifically, the substrate can comprise at least about 99 wt% silicon, based on the total weight of the substrate.

[0105] In some embodiments, the substrate can include isotropic graphite, more specifically, the substrate can include at least about 90 wt.% isotropic graphite, based on the total weight of the substrate, and more specifically, the substrate can include at least about 99 wt.% isotropic graphite.

[0106] In some embodiments, the substrate can include CFRC, and more specifically, the substrate can include at least about 90 wt.% isotropic graphite, based on the total weight of the substrate, and more specifically, the substrate can include at least about 99 wt.% CFRC.

[0107] In some embodiments, the substrate can be a cylinder, more particularly a cylinder having a diameter between about 5 cm and about 100 cm, and more particularly a cylinder having a diameter between about 15 cm and about 80 cm.

[0108] In some embodiments, the cylinder can have a thickness between about 1 mm and about 10 cm, more particularly between about 3 mm and about 5 cm, and particularly between about 5 mm and about 3 cm.

[0109] In some embodiments, the outer surface can include at least one disk-shaped pocket, the diameter of the recess can be between about 45 mm and about 700 mm, more particularly between about 100 mm and about 475 mm, and particularly between about 150 mm and about 300 mm, and / or the depth of the pocket can be between about 100 μm and about 2000 μm, more particularly between about 250 μm and about 1500 μm, and particularly between about 500 μm and about 1000 μm.

[0110] In some embodiments, the substrate can include one or more gas channels.

[0111] In some embodiments, the wall segment can include a first wall section and a second wall section, and the first and second wall sections can be disposed at an angle relative to one another.

[0112] In some embodiments, the second wall section extends orthogonally to the first wall section.

[0113] In some embodiments, the first wall section can have a length between about 0.1 cm and about 3 cm, more particularly between about 0.5 cm and about 2 cm, and particularly between about 1 cm and about 1.5 cm.

[0114] In some embodiments, the second wall section can have a length between about 1 cm and about 100 cm, more particularly between about 5 cm and about 75 cm, and particularly between about 25 cm and about 50 cm.

[0115] In some embodiments, the recess can have a first and a second opening, and the first opening can be disposed in the outer surface and the second opening can be disposed on the second outer surface of the substrate.

[0116] Coated Substrate The method according to the first aspect can provide a substrate with an improved coating geometry. In particular, the method according to the first aspect can be used to provide a substrate with a metal carbide coating, the metal carbide coating having a similar thickness in a section of the recess that is disposed closer to the outer surface as in another section that is disposed further away from the outer surface.

[0117] In a second aspect, the present disclosure relates to a substrate, the substrate comprising an outer surface and a recess disposed in the outer surface. The recess further comprises a wall segment comprising a metal carbide coating, and there is an edge disposed between the outer surface and the wall segment. The wall segment comprises a proximal section and a distal section, the proximal section being positioned closer to the edge than the distal section. A distance between the proximal section and the distal section in a direction perpendicular to the outer surface is at least 100 μm. The metal carbide coating in the distal section has a thickness of at least 70% of the thickness of the metal carbide coating in the proximal section.

[0118] The thickness in the proximal and / or distal sections can be averaged over a length of 10 μm along the wall segment. For example, if the recess extends into the bulk perpendicular to the surface, the proximal segment can be the average thickness of the metal carbide coating disposed next to the edge. For a section (such as the distal section) that is disposed at a specific distance from a reference point, the start and end points for averaging the metal carbide coating thickness can be equidistant from the intended distance from the reference point. For example, the thickness of the metal carbide coating in the distal section can be averaged starting from a point that is disposed 95 μm away from the proximal section in the vertical direction to a point that is disposed 105 μm away from the proximal section in the distal direction.

[0119] Additionally, the thickness of the metal carbide coating can be measured perpendicular to the surface of the underlying layer.

[0120] The term "outer surface" in the present disclosure can refer to a surface, on which no other surface of the substrate is disposed in a direction perpendicular to the surface. Alternatively or additionally, the term "outer surface" in the present disclosure can refer to a surface, on which at least one reference point is not surrounded by at least 50% by a wall segment extending away from the bulk. Alternatively or additionally, the term "outer surface" can refer to a surface, on which at least one reference point is not surrounded by a wall segment having a height of at least 1 cm, which extends away from the bulk within a radius of at least 2.5 cm, more particularly at least 3.5 cm, in particular at least 4 cm. For example, the substrate can include a disk-shaped pocket, the radius of the pocket being 700 mm. The interior of the pocket can still be considered as the outer surface, not a recess. Known processes can be used to provide metal carbide coatings on flat pockets with large diameters, because they are easily reached by the main gas flow. However, the method according to the first aspect is capable of providing a metal carbide coating over recesses of large depth and / or over recesses having a smaller diameter compared to flat pockets.

[0121] The term "wall segment" refers to a portion of a wall, more specifically a portion of a wall having a length of at least 100 μm, and in particular a portion of a wall having a length of at least 100 μm and a width of at least 10 μm. The width can also be measured along a curved surface, along a curved wall segment. A rectangular recess (wherein a rectangular recess refers to a recess having a rectangular top view) can be divided, for example, into four wall segments, each wall segment representing one side of the rectangle. A circular wall (e.g., a wall of a recess (e.g., a bore) having a circular top view) can also be divided into multiple wall segments. The term "top view" can refer to a view onto the outer surface, in particular a view onto the outer surface in a direction perpendicular to the outer surface.

[0122] The substrate according to the second embodiment can be used as a wafer carrier, for example in the semiconductor industry. Such a wafer carrier can have recesses in its outer surface for functionality. For example, the wafer carrier can include gas channels, which can be used to transport gas to rotate the wafer and / or the wafer carrier during the wafer coating process. However, the wafer coating process can be carried out at high temperatures. As a result, if the substrate includes a material that is susceptible to chemical attack (such as, for example, graphite), the gas stream can chemically attack the material along the gas channels (for example, along the wall segments of the recesses). Metal carbide coatings (particularly silicon carbide coatings) can protect the underlying substrate from chemical attack. Thus, a coating that penetrates deeper into the recesses or coats longer sections of the wall segments with a greater thickness can improve the chemical resistance of the substrate.

[0123] Coating Dimensions In some embodiments, the thickness of the metal carbide coating in the proximal section can be between about 20 μm and about 300 μm, more specifically between about 50 μm and about 250 μm, and in particular between about 80 μm and about 150 μm. Typically, processes that can provide a metal carbide coating into the recess and / or provide a homogeneous metal carbide coating result in a reduced growth rate compared to processes that deposit a metal carbide coating mainly on the outer surface and on parts of the recess that are located close to the outer surface. As a result, processes that can provide a metal carbide coating that penetrates into the recess and / or a homogeneous metal carbide coating result in a low metal carbide coating thickness. This is because a larger metal carbide coating thickness can only be achieved by excessive coating duration. A larger metal carbide coating thickness can improve chemical resistance. Furthermore, a larger metal carbide coating thickness can more effectively prevent the diffusion of impurities contained within the substrate from diffusing to the outer surface of the substrate, where they would contaminate, for example, a wafer in contact with the outer surface.

[0124] In some embodiments, the distance between the proximal and distal sections can be at least about 200 μm, more particularly at least about 400 μm, and especially at least about 600 μm. A larger distance between the proximal and distal sections relates to a larger section of the wall segment being homogeneously coated, which improves the chemical resistance of the wall segment.

[0125] In some embodiments, the distance between the proximal section and the edge can be at least about 200 μm, more particularly at least about 400 μm, and especially at least about 600 μm.

[0126] In some embodiments, the distance between the proximal section and the edge can be between about 200 μm and about 2 cm, more particularly between about 400 μm and about 1 cm, and especially between about 600 μm and about 800 μm. The proximal section disposed further away from the edge means that the metal carbide coating is applied deeper into the recess, which corresponds to better chemical resistance deeper into the recess.

[0127] In some embodiments, the exterior surface can also include a metal carbide coating. The substrate (e.g., graphite) can have a rough exterior surface. The rough exterior surface can damage an object (e.g., a wafer) placed on the exterior surface of the substrate. The metal carbide coating can make the exterior surface level and / or smooth, which can reduce the risk of damaging an object placed on the substrate.

[0128] In some embodiments, the thickness of the metal carbide coating of the distal section can be between about 80% and about 200%, more specifically between about 90% and about 160%, and especially between about 95% and about 120% of the thickness of the metal carbide coating of the proximal section. The above ranges specify a highly homogeneous metal carbide coating, which can improve the overall chemical resistance of the substrate. The method according to the first aspect may even be able to provide a metal carbide coating with step coverage of more than 100%, as can be seen in Figures 2 and 4. A coating with step coverage of more than 100% can be referred to as a superconformal coating. As mentioned above, the processes involved in chemical vapor deposition are not fully understood. However, without wishing to be bound by theory, the method according to the first aspect may be able to provide a superconformal metal carbide coating. The reason is that chlorine, which desorbs from the surface where the reactive species form the metal carbide coating, can be reabsorbed on its way to diffuse out of the recess. Due to re-adsorption, the chlorine may again block the deposition of the metal carbide coating onto the substrate. During this process, the chlorine concentration may increase along the wall segment toward the edge as the chlorine accumulates along the path toward the edge. Thus, depending on, for example, temperature, the chlorine may block more reaction sites at the top of the recess compared to the bottom of the recess.

[0129] Again, without wishing to be bound by theory, it is also possible that the precursor breaks down into smaller fragments in the main gas flow. These smaller fragments can include chlorine-containing species (especially HCl, when chlorine reacts with hydrogen present in the main gas flow). Chlorine can preferentially react with the graphite substrate surface compared to other precursor fragments, reducing the growth rate of the metal carbide coating on the surface. Because chlorine can be depleted from the main gas flow at the outer surface and at parts of the recess that are disposed closer to the outer surface due to surface reactions, the lower parts of the recess can be exposed to a lower chlorine concentration. Also, the precursor can be depleted at the lower parts of the recess compared to the outer surface or parts of the recess that are disposed closer to the outer surface. However, the depletion of chlorine at the lower parts of the recess can leave more reaction sites available for the precursor, thus resulting in an equal or even increased rate of metal carbide coating formation at the lower parts of the recess compared to the outer surface. In particular, the chlorine concentration may be more significantly depleted compared to the precursor concentration further into the recesses, resulting in a shift in their ratio relative to each other and shifting the reaction equilibrium towards surface reactions with the precursor.

[0130] In some embodiments, the thickness of the metal carbide coating on the distal section can be between about 80% and about 200%, more particularly between about 90% and about 160%, and especially between about 95% and about 120% of the thickness of the metal carbide coating on the outer surface. The metal carbide coating provided by the method according to the first aspect can also provide a superconformal metal carbide coating when comparing the distal section with the outer surface.

[0131] In some embodiments, the wall segments can have a length between about 200 μm and about 50 cm, more particularly between about 5 mm and about 40 cm, and particularly between about 5 cm and about 30 cm.

[0132] Plane Orientation In some embodiments, the wall segments and the outer surface can be disposed at an angle relative to one another, more specifically, the angle can be between about 45° and about 135°, in particular, the angle can be between about 70° and about 110°, and even more specifically, the angle can be between about 85° and about 95°. Wall segments that extend at an acute angle from the outer surface can be more difficult to coat compared to flatter angles. The method according to the first aspect can be used to provide a homogeneous metal carbide coating of at least 100 μm thickness on wall segments that are disposed at an acute angle from the outer surface.

[0133] In some embodiments, the wall segment and the exterior surface can be disposed substantially perpendicular or perpendicular to one another.

[0134] In some embodiments, the wall segment may have an opposing wall segment, and the distance between the wall segment and the opposing wall segment may be between about 250 μm and about 25000 μm, more specifically between about 500 μm and about 10000 μm, and in particular between about 1000 μm and about 7500 μm. For example, in a recess having a rectangular top view, the two opposing wall segments may be two opposing faces of the recess. In another example, in a circular recess, the two opposing wall segments may be two arcs, and the two arcs are disposed opposite each other. Then, the distance between the wall segment and the opposing wall segment in the circular recess may be the diameter of the circular recess.

[0135] In some embodiments, the ratio between the length of a wall segment and the distance between the wall segment and the opposing wall segment can be at least 1:1, more specifically at least 5:1, even more specifically at least 10:1, and especially at least 20:1. The term "length of a wall segment" within the present disclosure can refer to the distance between an edge and a lower edge disposed in the recess, the lower edge being disposed further from the outer surface than the edge. For example, in a cubic recess, the length of a wall segment can be the distance between the edge and the bottom of the recess. Additionally or alternatively, the term "length of a wall segment" within the present disclosure can refer to the distance between an edge and the closest point on a line parallel to the outer surface that intersects the lower edge, the lower edge being disposed further from the outer surface than the edge, and the other edge is not disposed in the recess closer to the outer surface and / or edge. For example, in a recess that includes a step, the length of a wall segment can be longer than the distance to the first step. Alternatively, the length of a wall segment can be the distance between the edge and the bottom of the recess when the bottom of the recess is disposed on a line perpendicular to the outer surface that intersects the edge.

[0136] In some embodiments, the ratio between the length of a wall segment and the distance between the wall segment and an opposing wall segment can be from about 1:1 to about 100:1, more specifically from about 10:1 to about 75:1, and especially from about 20:1 to about 50:1. Higher ratio recesses can be more difficult to coat because they are narrower and / or deeper.

[0137] Edge Surprisingly, it has been found that the method according to the first embodiment is capable of providing a metal carbide coating with a close contour even at the edge. FIG. 10 shows an SEM image of a substrate edge coated by a conventional method, and FIG. 9 shows an SEM image of a substrate edge coated by a method according to the first embodiment. As can be seen in FIG. 10, the edge coated by the conventional method results in a thicker metal carbide coating on both sides of the edge in the area proximal to the edge, eventually forming a bulge on the edge. In comparison in FIG. 9, the edge coated by the method according to the first embodiment results in an edge where the metal carbide coating closely follows the contour along the edge and the area disposed proximal to the edge. The bulge generated in the conventional process may result, for example, in that an object placed on the substrate is not in direct contact with the substrate. If the substrate is used, for example, as a susceptor for heating an object (such as, for example, a wafer), the bulge may therefore reduce the homogeneity and effectiveness of heat transfer. This is because it lifts the wafer away from the outer surface of the substrate. Additionally, the bulge can constrict the diameter of the recess. For example, if the recess is a gas channel or part of a gas channel, the bulge can constrict the gas flow or introduce undesired turbulence.

[0138] Removing the bulges may require post-processing, which increases the cost of the final product. Additionally, post-processing may reduce the metal carbide coating thickness, may damage the metal carbide coating, or may not be possible.

[0139] In some embodiments, the metal carbide coating follows the contours of the underlying substrate, particularly, the metal carbide coating follows the contours of the underlying substrate at the edges.

[0140] In some embodiments, the change in thickness of the metal carbide coating along the edge can be less than 60%, more particularly less than 50%, and especially less than 45%. Along the edge of a rectangle, the thickness of the metal carbide coating close to the full contour will vary in thickness by 41.4%, because the thickness of the metal carbide coating at the apex of the edge will have the thickness of the metal carbide coating in the area proximal to the edge multiplied by the square root of two.

[0141] In some embodiments, the outer surface can include a first portion adjacent to the edge and the wall segment can include a second portion adjacent to the edge, the distance between the first portion and the edge and the distance between the second portion and the edge corresponding to 110% of the thickness of the metal carbide coating in the proximal section, and the thickness of the metal carbide coating of the first portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and especially between about 95% and about 105% of the thickness of the metal carbide coating of the second portion.

[0142] As mentioned above, the thickness of the metal carbide coating can be determined perpendicular to the surface of the underlying layer. However, in a section directly adjacent to a sharp inner edge having, for example, a 45° angle, the thickness of the metal carbide coating when measured perpendicular to the surface corresponds to the length of the wall segment. In a completely coated inner edge, the thickness of the metal carbide coating in the second portion may not be measurable with respect to a distance corresponding to the thickness of the metal carbide coating in the first portion.

[0143] In some embodiments, the thickness of the metal carbide coating in the first portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and particularly between about 95% and about 105%, of the thickness of the metal carbide coating in the proximal section.

[0144] In some embodiments, the thickness of the metal carbide coating in the second portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and particularly between about 95% and about 105%, of the thickness of the metal carbide coating in the proximal section.

[0145] In some embodiments, the edge can be an outer edge.

[0146] In some embodiments, the edge can be an inner edge.

[0147] Substrate Material In some embodiments, the substrate can comprise carbon, more specifically, the substrate can comprise at least about 90 wt% carbon, and more specifically, the substrate can comprise at least about 99 wt% carbon, based on the total weight of the substrate.

[0148] In some embodiments, the substrate can include graphite, more specifically, the substrate can include at least about 90 wt% graphite, and in particular, the substrate can include at least about 99 wt% graphite, based on the total weight of the substrate. Graphite can exhibit high temperature resistance. Furthermore, graphite can be used as a susceptor that will be heated by electromagnetic energy. However, graphite can be susceptible to chemical attack at high temperatures. Coating graphite with a metal carbide coating, and especially a silicon carbide coating, can improve its chemical resistance and therefore its utility at elevated temperatures.

[0149] The term "graphite" is well known and given its common meaning in the art. More specifically, the term "graphite" can refer to a material that includes crystalline carbon in a hexagonal crystal structure. Alternatively or additionally, the term "graphite" can refer to a material that includes at least about 60 at% crystalline carbon in a hexagonal crystal structure, more specifically at least about 80 at%, particularly at least about 83 at%. Alternatively or additionally, the term "graphite" can refer to a material that has a degree of graphitization of at least about 69 at%, more specifically at least about 80 at%, particularly at least about 83 at%.

[0150] The degree of graphitization of a carbonaceous substrate can be measured by XRD. The crystalline carbon in graphite forms a honeycomb lattice. XRD measures the interplanar distance d between the lattices. 001can be used to measure the interplanar distance between about 0.3381 and about 0.3354, more specifically between about 0.3371 and about 0.3354, and especially between about 0.3369 and about 0.3354. To perform XRD measurements on graphite substrates according to the present disclosure, the gradient and transition layers must be removed and only the underlying carbonaceous material shall be used for the measurements.

[0151] The interplanar distance can also be used to calculate the degree of graphitization by the following formula:

[0152] Graphitization degree = (0.3440-d 00l ) / (0.3440-0.3354)

[0153] 0.3340 corresponds to the interplanar spacing of turbostratic graphite, and 0.3354 corresponds to the interplanar spacing in a perfect graphite crystal.

[0154] In some embodiments, the substrate can comprise silicon, more specifically, the substrate can comprise at least about 90 wt% silicon, and more specifically, the substrate can comprise at least about 99 wt% silicon, based on the total weight of the substrate.

[0155] In some embodiments, the substrate can include isotropic graphite, more specifically, the substrate can include at least about 90 wt% isotropic graphite, and more specifically, the substrate can include at least about 99 wt% isotropic graphite, based on the total weight of the substrate. Isotropic graphite can have improved mechanical properties compared to other graphite types (e.g., extruded graphite or vibromolded graphite, etc.). Furthermore, isotropic graphite can have pores with smaller average pore diameters, which can allow the metal carbide coating to seal those pores, which can substantially improve chemical resistance and / or reduce the risk of impurities reaching objects placed on the substrate.

[0156] In some embodiments, the substrate can include CFRC (carbon fiber reinforced carbon), more specifically, the substrate can include at least about 90 wt% isotropic graphite, based on the total weight of the substrate, and more specifically, the substrate can include at least about 99 wt% CFRC, which can exhibit improved mechanical properties compared to other carbonaceous substrates.

[0157] In some embodiments, the substrate can be a cylinder, more specifically, a cylinder having a diameter between about 5 cm and about 100 cm, and more specifically, a cylinder having a diameter between about 15 cm and about 80 cm. The substrate being a cylinder can refer to the fact that the basic body of the cylinder is a cylinder, but that the substrate includes other features that deviate from the basic body (e.g., a recess disposed therein, an edge, a skirt along the outer perimeter, etc.).

[0158] In some embodiments, the cylinder can have a thickness between about 1 mm and about 10 cm, more particularly between about 3 mm and about 5 cm, and particularly between about 5 mm and about 3 cm.

[0159] The method according to the first aspect can be used to coat substrates of larger size compared to other chemical vapor deposition methods, particularly other chemical vapor deposition methods used to produce homogeneous metal carbide coatings.

[0160] In some embodiments, the outer surface can include at least one disk-shaped pocket, the diameter of the pocket can be between about 45 mm and about 700 mm, more specifically between about 100 mm and about 475 mm, and particularly between about 150 mm and about 300 mm, and / or the depth of the pocket can be between about 100 μm and about 2000 μm, more specifically between about 250 μm and about 1500 μm, and particularly between about 500 μm and about 1000 μm. The disk-shaped pocket can be used, for example, to place wafers on the substrate and secure them in place, especially when the substrate can be used as a susceptor (e.g., graphite).

[0161] Coating Materials In some embodiments, the metal carbide coating can include at least about 90 wt% metal carbide based on the total weight of the coating, more specifically, the metal carbide coating can include at least about 99 wt% metal carbide, and more specifically, the metal carbide coating can be composed of metal carbide.

[0162] The term "metal carbide" coating herein can refer to any carbide including metals, metalloids, and / or transition metals. Any metal carbide coating according to the present disclosure can be, but is not limited to, silicon carbide, titanium carbide, tantalum carbide, or tungsten carbide.

[0163] In some embodiments, the metal carbide may include silicon carbide.

[0164] In some embodiments, the metal carbide coating may include a plurality of carbide crystals.

[0165] In some embodiments, the metal carbide coating can be characterized by a full width at half maximum of the (111) peak in XRD between about 0.300° and about 1.000°, more particularly between about 0.350° and about 0.800°, and especially between about 0.400° and about 0.750°. The full width at half maximum of the metal carbide coating produced by the method according to the first aspect can result in a larger full width at half maximum of the (111) peak in XRD compared to methods performed at higher temperatures. The higher full width at half maximum of the (111) peak can be correlated with a smaller crystal size in the metal carbide coating. Smaller crystals can form a smoother metal carbide coating compared to larger sized crystals, which can reduce surface roughness and improve heat transfer to an object placed on the metal carbide coating. XRD measurements can be performed, for example, with a PANalytical X'Pert PRO powder X-ray diffractometer by Malvern Panalytical (UK / NL). Irradiation can be performed with a Cu-Kα beam and Bragg-Brentano geometry. The measurement mode can be set to θ-2θ and the measurement range can be set from 20° to 140° with a step size of 0.033°.

[0166] Gas Channel As mentioned above, the substrate may include one or more gas channels in some embodiments, for example to turn a wafer placed on the substrate. The gas channels are depicted in FIG. 8. These gas channels may include a first gas channel section (1000) and then a second gas channel section (1200), where the first gas channel section (1000) extends from the outer surface into the bulk, in particular perpendicular to the outer surface, and the second gas channel section (1200) extends in the bulk parallel to the outer surface. Between the first gas channel section (1000) and the second gas channel section (1200), an edge (1100) may be disposed. Thus, a recess in the substrate may include a section extending in the bulk parallel to the outer surface. It may be difficult to coat such a recess with a metal carbide coating of sufficient thickness.

[0167] In particular, the section of the recess that is arranged in the bulk parallel to the outer surface can be blocked from the main gas flow, and thus the metal carbide coating of this section depends on diffusion from the main gas flow into the recess section below the outer surface. In conventional methods, the precursor may already be depleted when it reaches the section of the recess that is arranged parallel to the outer surface. It has been found that the method according to the first aspect allows the metal carbide coating of these sections to be provided with a metal carbide coating of sufficient thickness as well. Without wishing to be bound by theory, it is believed that the reactive sites of the substrate can be blocked by chlorine, which thus prevents the reaction of the precursor and / or reactive species at the reactive sites with the substrate. As a result, the precursor and / or reactive species can be transported further into the recess, where it can react with the reactive sites.

[0168] In some embodiments, the wall segment can include a first wall section and a second wall section, and the first and second wall sections can be disposed at an angle relative to one another.

[0169] In some embodiments, the second wall section extends perpendicular to the first wall section. As mentioned above, for example, the gas channel can include a section that is arranged parallel to the outer surface, as depicted in FIG. 9. Thus, in some embodiments, the first wall section can extend perpendicular from the outer surface, and the second section can extend perpendicular from the first wall section, with the second wall section extending parallel to the outer surface. This can, for example, allow for feeding the gas channel from the outer edge of the substrate.

[0170] In some embodiments, the first wall section can have a length between about 0.1 cm and about 3 cm, more particularly between about 0.5 cm and about 2 cm, and particularly between about 1 cm and about 1.5 cm.

[0171] In some embodiments, the second wall section can have a length between about 1 cm and about 100 cm, more particularly between about 5 cm and about 75 cm, and particularly between about 25 cm and about 50 cm.

[0172] In some embodiments, the recess can have a first and a second opening, the first opening can be disposed in the outer surface and the second opening can be disposed on a second outer surface of the substrate, The second opening can be used, for example, to pump a gas (such as air or an inert gas) into or remove the recess.

[0173] In some embodiments, the second edge can be disposed between the first wall segment and the second wall segment, the first wall segment can include a third portion adjacent to the second edge, and the second wall segment can include a fourth portion adjacent to the second edge, the distance between the third portion and the second edge and the distance between the fourth portion and the edge correspond to 110% of the thickness of the metal carbide coating in the proximal section, and the thickness of the metal carbide coating of the first portion can be between about 80% and about 120%, more specifically between about 90% and about 110%, and in particular between about 95% and about 105% of the thickness of the metal carbide coating of the second portion. As mentioned above, the method according to the first aspect can make it possible to coat the edge in the recess with a metal carbide coating of homogeneous thickness. The second edge can be, for example, an edge with a gas channel, for example, an edge disposed between a first bore perpendicular to the outer surface and a second bore extending parallel to the outer surface. Coating the edges in the gas channel with a homogenous thickness can improve the flow behavior in the gas channel. In some embodiments, the second edge can be a lower edge.

[0174] In a third aspect, the present disclosure relates to a substrate including an outer surface and a recess disposed therein. The recess includes a wall segment, with an edge disposed between the outer surface and the wall segment. The outer surface and the wall segment include a metal carbide coating. Furthermore, the wall segment includes a proximal section, with a distance between the edge and the proximal section being 500 μm. The outer surface includes a first portion adjacent to the edge, and the wall segment includes a second portion adjacent to the edge. The distance between the first portion and the edge and the distance between the second portion and the edge correspond to 110% of the thickness of the metal carbide coating at the proximal section. Furthermore, the thickness of the metal carbide coating at the first portion is between about 80% and about 120%, more particularly between about 90% and about 110%, and in particular between about 95% and about 105% of the thickness of the metal carbide coating at the second portion. As mentioned above, the method according to the first aspect can be used to provide a metal carbide coating having a uniform thickness along the edge of a substrate. The technical advantages of a metal carbide coating having a uniform thickness along the edge are outlined above.

[0175] Experimental Section Sample preparation The samples were prepared by coating with isotropic graphite sold under the trade name Sigrafine 810 by SGL Carbon Group GmbH (Germany).

[0176] The rectangular samples had a length of 5 cm, a width of 2.5 cm, and a thickness of 0.2 cm before coating. The samples contained multiple recesses with a depth of 1000 μm and a width of 300 μm running along the entire diameter of the sample. A laboratory-scale low-pressure CVD reactor was used as the reactor. The reactor contained a heatable graphite susceptor with a size of 20 cm×8 cm and a thickness of 2 cm, on which the samples were placed. Air was then evacuated from the reactor. The reactor was then flushed with carrier gas (H2) and heated to the desired temperature. Process gas was then introduced into the reactor to start the coating process. The composition of the process gas is outlined for each experiment below. The coating durations stated below relate to the duration the samples were exposed to the process gas in the reactor. The coating process was stopped by stopping the process gas flow, the reactor was flushed with carrier gas (H2), and the reactor was allowed to cool. The reactor was again evacuated and backfilled with inert gas, after which it was opened and the sample removed.

[0177] The sample is placed in a suitable position in an oven, where the oven exhibits a stable temperature profile, and where the sample is in contact with a process gas flow, particularly a laminar process gas flow.

[0178] First experiment In the first experiment, the effect of temperature on the step coverage and average growth rate in the SiCl4 + ethene and MTS processes was determined.

[0179] [Table 1]

[0180] The results are shown in Figures 2 and 3. Step coverage was determined by measuring the metal carbide coating thickness at the bottom of the recess compared to the metal carbide coating at the top of the recess in the section disposed next to the edge.

[0181] FIG. 2 shows that the step coverage of the CVD process using SiCl4 was greater than that of the CVD process using MTS. Moreover, the step coverage was greatest between about 950°C and about 1100°C, especially at approximately 1000°C. Furthermore, FIG. 3 shows that the average growth rate of the SiCl4 process significantly exceeded that of the MTS process in the temperature window between 950°C and over 1100°C. To measure the average growth rate, the growth rate was measured at 10 points arranged along the wall of the recess. The growth rate was measured at the outer surface of the substrate 5 μm from the edge and at the bottom of the recess. An additional 8 points were arranged at equal distances between the edge and the bottom. Additionally, FIG. 3 shows that the average growth rate in the SiCl4 process decreases above 1100°C, while the average growth rate in the MTS process increases significantly above 1100°C.

[0182] Second experiment In a second experiment, the effect of partial pressure on step coverage and average growth rate in the SiCl4 + ethene and MTS processes was determined.

[0183] [Table 2]

[0184] Figures 4 and 5 show the results of the second experiment. As the partial pressure of SiCl4 increases, the step coverage increases, while the step coverage by MTS decreases above a partial pressure of 0.2 mbar. Furthermore, the average growth rate increases with increasing SiCl4 partial pressure, but the rate of increase decreases with increasing partial pressure. MTS achieves a maximum at 0.2 mbar partial pressure and decreases above that.

[0185] Third experiment In a third experiment, the effect of HCl on the step coverage and average growth rate in the SiCl4+ethene process was determined.

[0186] [Table 3]

[0187] The results are shown in Figures 6 and 7. The results show that the step coverage can be increased with increasing HCl partial pressure, but the average growth is significantly reduced.

[0188] Fourth experiment In a fourth experiment, different full width at half maximum values ​​of the SiC(111) peak were measured under different process conditions.

[0189] XRD measurements were performed with a PANalytical X'Pert PRO powder X-ray diffractometer from Malvern Panalytical (UK / Netherlands). Irradiation was performed with a Cu-Kα beam and Bragg-Brentano geometry. The measurement mode was set to θ-2θ and the measurement range was set from 20° to 140° with a step size of 0.033°.

[0190] [Table 4]

[0191] As can be seen, all full widths at half maximum (FWHM) are in the range of between about 0.300 and about 1.000, more specifically in the range of between about 0.350 and about 0.800, and especially in the range of between about 0.400 and about 0.750.

[0192] Aspects 1. A substrate comprising: The substrate includes an outer surface and a recess disposed in the outer surface; the recess includes a wall segment including a metal carbide coating; There is an edge disposed between the exterior surface and the wall segment; The wall segment includes a proximal section and a distal section; The proximal section is positioned closer to the edge compared to the distal section; the distance between the proximal and distal sections in a direction perpendicular to the outer surface is at least 100 μm; A substrate, wherein the metal carbide coating in the distal section has a thickness that is at least 70% of the thickness of the metal carbide coating in the proximal section.

[0193] Coating Dimensions 2. The substrate of embodiment 1, wherein the thickness of the metal carbide coating in the proximal section is between about 20 μm and about 300 μm, more particularly between about 50 μm and about 250 μm, and in particular between about 80 μm and about 150 μm.

[0194] 3. The substrate of any one of the preceding embodiments, wherein the distance between the proximal and distal sections is at least about 200 μm, more particularly at least about 400 μm, and in particular at least about 600 μm.

[0195] 4. The substrate of any one of the preceding embodiments, wherein the distance between the proximal and distal sections is between about 200 μm and about 2 cm, more particularly between about 400 μm and about 1 cm, and in particular between about 600 μm and about 800 μm.

[0196] 5. The substrate of any one of the preceding embodiments, wherein the distance between the proximal section and the edge is at least about 200 μm, more particularly at least about 400 μm, and in particular at least about 600 μm.

[0197] 6. The substrate of any one of the preceding embodiments, wherein the distance between the proximal section and the edge is between about 200 μm and about 2 cm, more particularly between about 400 μm and about 1 cm, and in particular between about 600 μm and about 800 μm.

[0198] 7. The substrate of any one of the preceding aspects, wherein the outer surface also comprises a metal carbide coating.

[0199] 8. The substrate of any one of the preceding aspects, wherein the thickness of the metal carbide coating in the distal section is between about 80% and about 200%, more particularly between about 90% and about 160%, and particularly between about 95% and about 120%, of the thickness of the metal carbide coating in the proximal section.

[0200] 9. The substrate of any one of the preceding embodiments, wherein the thickness of the metal carbide coating on the distal section is between about 80% and about 200%, more specifically between about 90% and about 160%, and particularly between about 95% and about 120%, of the thickness of the metal carbide coating on the outer surface.

[0201] 10. The substrate of any one of the preceding embodiments, wherein the wall segments have a length between about 200 μm and about 50 cm, more particularly between about 5 mm and about 40 cm, and particularly between about 5 cm and about 30 cm.

[0202] Plane Orientation 11. The substrate of any one of the preceding embodiments, wherein the wall segments and the outer surface are disposed at a predetermined angle relative to one another, more specifically, the angle is between about 45° and about 135°, particularly, the angle is between about 70° and about 110°, and even more specifically, the angle is between about 85° and about 95°.

[0203] 12. The substrate of any one of the preceding aspects, wherein the wall segments and the outer surface are disposed substantially perpendicular or perpendicular to one another.

[0204] 13. The substrate of any one of the preceding embodiments, wherein the wall segment has an opposing wall segment and the distance between the wall segment and the opposing wall segment is between about 250 μm and about 25000 μm, more particularly between about 500 μm and about 10000 μm, and in particular between about 1000 μm and about 7500 μm.

[0205] 14. The substrate of embodiment 13, wherein the ratio between the length of a wall segment and the distance between the wall segment and an opposing wall segment is at least 1:1, more particularly at least 5:1, even more particularly at least 10:1, and in particular at least 20:1.

[0206] 15. The substrate of embodiment 13 or 14, wherein the ratio between the length of a wall segment and the distance between the wall segment and an opposing wall segment is between about 1:1 and about 100:1, more particularly between about 10:1 and about 75:1, and particularly between about 20:1 and about 50:1.

[0207] Edge 16. The substrate of any one of the preceding aspects, wherein the metal carbide coating follows the contours of the underlying substrate, in particular, the metal carbide coating follows the contours of the underlying substrate at the edges.

[0208] 17. The substrate of any one of the preceding aspects, wherein the variation in thickness of the metal carbide coating along the edge is less than 60%, more particularly less than 50%, and especially less than 45%.

[0209] 18. The outer surface includes a first portion adjacent the edge and the wall segment includes a second portion adjacent the edge; a distance between the first portion and the edge and a distance between the second portion and the edge corresponding to 110% of a thickness of the metal carbide coating in the proximal section; 13. The substrate of any one of the preceding aspects, wherein a thickness of the metal carbide coating of the first portion is between about 80% and about 120%, more specifically between about 90% and about 110%, and particularly between about 95% and about 105%, of a thickness of the metal carbide coating of the second portion.

[0210] 19. The substrate of embodiment 18, wherein the thickness of the metal carbide coating in the first portion is between about 80% and about 120%, more specifically between about 90% and about 110%, and particularly between about 95% and about 105%, of the thickness of the metal carbide coating in the proximal section.

[0211] 20. The substrate of aspect 18 or 19, wherein the thickness of the metal carbide coating in the second portion is between about 80% and about 120%, more particularly between about 90% and about 110%, and particularly between about 95% and about 105%, of the thickness of the metal carbide coating in the proximal section.

[0212] 21. The substrate of any one of the preceding aspects, wherein the edge is an outer edge.

[0213] 22. The substrate of any one of aspects 1 to 20, wherein the edge is an inner edge.

[0214] Substrate Material 23. The substrate of any one of the preceding embodiments, wherein the substrate comprises carbon, more specifically, the substrate comprises at least about 90 wt% carbon, based on the total weight of the substrate, and in particular, the substrate comprises at least about 99 wt% carbon.

[0215] 24. The substrate of any one of the preceding embodiments, wherein the substrate comprises graphite, more particularly, the substrate comprises at least about 90 wt.% graphite, based on the total weight of the substrate, and in particular, the substrate comprises at least about 99 wt.% graphite.

[0216] 25. The substrate of any one of the preceding embodiments, wherein the substrate comprises silicon, more specifically, the substrate comprises at least about 90 wt% silicon, based on the total weight of the substrate, and in particular, the substrate comprises at least about 99 wt% silicon.

[0217] 26. The substrate of any one of the preceding embodiments, wherein the substrate comprises isotropic graphite, more particularly, the substrate comprises at least about 90 wt.% isotropic graphite, based on the total weight of the substrate, and in particular, the substrate comprises at least about 99 wt.% isotropic graphite.

[0218] 27. The substrate of any one of the preceding embodiments, wherein the substrate comprises CFRC, more particularly, the substrate comprises at least about 90 wt.% isotropic graphite, based on the total weight of the substrate, and in particular, the substrate comprises at least about 99 wt.% CFRC.

[0219] 28. The substrate of any one of the preceding embodiments, wherein the substrate is a cylinder, more particularly a cylinder having a diameter between about 5 cm and about 100 cm, and in particular a cylinder having a diameter between about 15 cm and about 80 cm.

[0220] 29. The substrate of embodiment 28, wherein the cylinder has a thickness between about 1 mm and about 10 cm, more specifically between about 3 mm and about 5 cm, and particularly between about 5 mm and about 3 cm.

[0221] 30. The substrate of any one of the preceding embodiments, wherein the outer surface comprises at least one disk-shaped pocket, the diameter of the recess being between about 20 mm and about 700 mm, more particularly between about 45 mm and about 475 mm, in particular between about 100 mm and about 300 mm, and / or the depth of the recess being between about 150 μm and about 2000 μm, more particularly between about 250 μm and about 1500 μm, in particular between about 500 μm and about 1000 μm.

[0222] Metal Carbide Coating Materials 31. The substrate of any one of the preceding aspects, wherein the metal carbide coating comprises at least about 90 wt.% metal carbide, based on the total weight of the coating; more specifically, the metal carbide coating can comprise at least about 99 wt.% metal carbide, and in particular, the metal carbide coating can be composed of metal carbide.

[0223] 32. The substrate of any one of the preceding embodiments, wherein the metal carbide comprises silicon carbide.

[0224] 33. The substrate of any one of the preceding aspects, wherein the metal carbide coating comprises a plurality of carbide crystals.

[0225] 34. The substrate of any one of the preceding embodiments, wherein the metal carbide coating is characterized by a (111) full width at half maximum of between about 0.300 and about 1.000, more specifically between about 0.350 and about 0.800, and particularly between about 0.400 and about 0.750, as measured by XRD.

[0226] Gas Channel 35. The substrate of any one of the preceding embodiments, wherein the wall segment includes a first wall section and a second wall section, the first and second wall sections being disposed at a predetermined angle relative to one another.

[0227] 36. The substrate of embodiment 35, wherein the second wall section extends perpendicular to the first wall section.

[0228] 37. The substrate of embodiment 35 or 36, wherein the first wall section has a length between about 0.1 cm and about 3 cm, more particularly between about 0.5 cm and about 2 cm, and particularly between about 1 cm and about 1.5 cm.

[0229] 38. The substrate of any one of aspects 35 to 37, wherein the second wall section has a length between about 1 cm and about 100 cm, more particularly between about 5 cm and about 75 cm, and particularly between about 25 cm and about 50 cm.

[0230] 39. A substrate according to any one of the preceding aspects, wherein the recess has first and second openings, the first opening being disposed in the outer surface and the second opening being disposed on a second outer surface of the substrate.

[0231] 40. The second edge is disposed between the first wall section and the second wall section; the first wall section includes a third portion adjacent the second edge, and the second wall section includes a fourth portion adjacent the second edge, a distance between the third portion and the second edge and a distance between the fourth portion and the edge corresponding to 110% of a thickness of the metal carbide coating in the proximal section; The substrate of any one of aspects 35 to 39, wherein the thickness of the metal carbide coating of the first portion is between about 80% and about 120%, more particularly between about 90% and about 110%, and particularly between about 95% and about 105%, of the thickness of the metal carbide coating of the second portion.

[0232] process 41. A method for coating a substrate with a metal or transition metal carbide by thermal chemical vapor deposition, the method comprising: - placing a substrate in a reaction chamber; - supplying SiCl4, ethene, and a carrier gas to a reaction chamber; Including, The process temperature within the reaction chamber is between about 900°C and about 1050°C.

[0233] 42. The method of embodiment 41, wherein the process temperature is between about 925°C and about 1025°C, more specifically, between about 950°C and about 1000°C.

[0234] 43. The method of embodiment 41 or 42, wherein the method is carried out for a duration of between about 20 minutes and about 600 minutes, more particularly between about 40 minutes and about 400 minutes, and particularly between about 60 minutes and about 240 minutes.

[0235] 44. The method of any one of aspects 41 to 43, wherein the total pressure in the reaction chamber is between about 1 mbar and about 1085 mbar, more particularly between about 5 mbar and about 100 mbar, and in particular between about 7 mbar and about 15 mbar.

[0236] 45. The method of any one of aspects 41 to 44, wherein SiCl4 and ethene are provided as a precursor mixture, and the atomic ratio between silicon and carbon in the precursor mixture is between about 0.7 and about 1.3, more specifically between about 0.8 and about 1.2, and particularly between about 0.9 and about 1.1.

[0237] 46. ​​The method of any one of aspects 41 to 44, wherein the method can include a first and a second step, the first step including a step of supplying SiCl4 to the reaction chamber, and the second step including a step of supplying ethene to the reaction chamber, and in particular, the first step and the second step are performed alternately.

[0238] 47. The method of embodiment 46, wherein the method can include a purging step, the purging step occurring between the first step and the second step and / or between the second step and the first step, the purging step including supplying only carrier gas to the reaction.

[0239] 48. The method of aspect 46 or 47, wherein the duration of the first and / or second steps can be between about 1 second and about 5 seconds, more specifically between about 2.5 seconds and about 3.5 seconds, and / or the duration of the purge step can be between about 0.5 seconds and about 3 seconds, more specifically between about 0.8 seconds and about 1.2 seconds.

[0240] 49. The method of any one of the preceding embodiments, wherein the carrier gas additionally comprises HCl or Cl2, in particular HCl.

[0241] 50. The method of embodiment 45 or 49, wherein the atomic ratio between chlorine and silicon in the precursor mixture is between about 3.5:1 and about 5:1, more particularly between about 3.8:1 and about 4.7:1, and particularly between about 4:1 and about 4.5:1.

[0242] 51. The method of any one of the preceding embodiments, wherein the carrier gas comprises H2, and more specifically, the molar ratio between H2 and silicon in the aggregate of the carrier gas and the precursor mixture is between about 10:1 and about 100:1, even more specifically, between about 20:1 and about 70:1, and in particular, between about 32:1 and about 50:1.

[0243] 52. The method of any one of the preceding embodiments, wherein the carrier gas additionally comprises an inert gas, more particularly comprising N2 and / or Ar, and especially comprising N2.

Claims

1. A substrate, the substrate includes an outer surface and a recess disposed in the outer surface; the recess includes a wall segment including a metal carbide coating; an edge disposed between the outer surface and the wall segment; the wall segment includes a proximal section and a distal section; the proximal section is positioned closer to the edge than the distal section; a distance between the proximal section and the distal section in a direction perpendicular to the outer surface is at least 100 μm; A substrate, wherein the metal carbide coating in the distal section has a thickness that is at least 70% of a thickness of the metal carbide coating in the proximal section.

2. 2. The substrate of claim 1, wherein the thickness of the metal carbide coating in the proximal section is between about 20 μm and about 300 μm, more particularly between about 50 μm and about 250 μm, and in particular between about 80 μm and about 150 μm.

3. The substrate according to claim 1 or 2, wherein the distance between the proximal section and the distal section is at least about 200 μm, more particularly at least about 400 μm, in particular at least about 600 μm.

4. 4. The substrate according to claim 1, wherein the distance between the proximal section and the edge is at least about 200 μm, more particularly at least about 400 μm, in particular at least about 600 μm.

5. The substrate of claim 1 , wherein the outer surface also comprises the metal carbide coating.

6. 6. The substrate according to claim 1 , wherein the thickness of the metal carbide coating in the distal section is between about 80% and about 200%, more particularly between about 90% and about 160%, in particular between about 95% and about 120%, of the thickness of the metal carbide coating in the proximal section.

7. 7. The substrate according to claim 1, wherein the thickness of the metal carbide coating in the distal section is between about 80% and about 200%, more particularly between about 90% and about 160%, in particular between about 95% and about 120%, of the thickness of the metal carbide coating on the outer surface.

8. 8. The substrate of claim 1 , wherein the wall segment has an opposing wall segment, the distance between the wall segment and the opposing wall segment being between about 250 μm and about 25000 μm, more particularly between about 500 μm and about 10000 μm, in particular between about 1000 μm and about 7500 μm.

9. the outer surface includes a first portion adjacent the edge and the wall segment includes a second portion adjacent the edge; a distance between the first portion and the edge and a distance between the second portion and the edge correspond to 110% of a thickness of the metal carbide coating in the proximal section; 9. The substrate according to claim 1 , wherein the thickness of the metal carbide coating on the first portion is between about 80% and about 120%, more particularly between about 90% and about 110%, and in particular between about 95% and about 105%, of the thickness of the metal carbide coating on the second portion.

10. the substrate comprises carbon, in particular graphite, more particularly the substrate comprises at least about 90 wt. % carbon, in particular the substrate comprises at least about 99 wt. % carbon, based on the total weight of the substrate; or 10. The substrate according to claim 1 , wherein the substrate comprises silicon, more particularly the substrate comprises at least about 90 wt.% silicon, in particular the substrate comprises at least about 99 wt.% silicon, based on the total weight of the substrate.

11. The substrate of claim 1 , wherein the metal carbide coating comprises silicon carbide.

12. 12. The substrate of claim 1, wherein the metal carbide coating is characterized by a (111) full width at half maximum, as measured by XRD, of between about 0.300 and about 1.000, more particularly between about 0.350 and about 0.800, and especially between about 0.400 and about 0.

750.

13. a second edge disposed between the first wall section and the second wall section; the first wall section includes a third portion adjacent the second edge, and the second wall section includes a fourth portion adjacent the second edge, a distance between the third portion and the second edge and a distance between the fourth portion and the edge corresponding to 110% of a thickness of the metal carbide coating in the proximal section; 13. The substrate of claim 1, wherein the thickness of the metal carbide coating in the first portion is between about 80% and about 120%, more particularly between about 90% and about 110%, and in particular between about 95% and about 105%, of the thickness of the metal carbide coating in the second portion.

14. 1. A method for coating a substrate with a metal or transition metal carbide by thermal chemical vapor deposition, comprising the steps of: placing a substrate in a reaction chamber; SiCl ４ supplying ethene and a carrier gas to the reaction chamber; The process temperature in the reaction chamber is between about 900°C and about 1050°C.

15. The carrier gas may additionally contain HCl or Cl ２ 15. The method according to claim 14, comprising:

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