Polycrystalline sic molded body

Abstract

Provided are: a polycrystalline SiC molded body having a crystal grain size controlled within a specific range and having a low volume resistivity; and a method for manufacturing the same. A SiC molded body having a small crystal grain size is considered to be preferable, because general consumption proceeds preferentially from crystal grain boundaries, leading to a reduction of particles generated during the consumption, while a SiC molded body having a large crystal grain size has a reduced volume resistivity. In order to suitably use a SiC molded body for uses such as a heater among members for a semiconductor manufacturing device, the present invention provides a polycrystalline SiC molded body wherein the average crystal grain size is 5.5-25.0 μm, the nitrogen concentration is 0.27 × 1020 particles / cm3 to 5.4 × 1020 particles / cm3, and the product of the carrier density × the Hall mobility is 4.0 × 1020 particles / cmVsec to 100 × 1020 particles / cmVsec.

Description

Polycrystalline SiC molded body

[0001] The present invention relates to a polycrystalline SiC compact and a method for producing the same.

[0002] Polycrystalline SiC (silicon carbide) compacts have excellent mechanical strength, electrical properties, heat resistance, chemical stability, and the like, and are used in a variety of industrial applications. For example, polycrystalline SiC compacts are used in high-temperature and high-purity atmospheres. Typical applications include dummy wafers and components for semiconductor manufacturing equipment, such as components constituting semiconductor manufacturing equipment.

[0003] For example, polycrystalline SiC molded bodies used as semiconductor manufacturing equipment components are generally plate-shaped. The main surface of the polycrystalline SiC molded body is the growth direction of the CVD film, and in the case of a plate-shaped polycrystalline SiC molded body, both the front and back surfaces can be main surfaces, excluding the side surfaces. The thickness of the polycrystalline SiC molded body varies depending on the film formation time, and can be formed to any thickness. Disc diameters of approximately 100 mm to 300 mm are known.

[0004] Polycrystalline SiC molded bodies as semiconductor manufacturing equipment components can also be suitably used as cylindrical polycrystalline SiC molded bodies by depositing a film on a rod-shaped substrate. In this case, the main surface of the polycrystalline SiC molded body is the growth direction of the CVD film, and if the polycrystalline SiC molded body is cylindrical, both the surface and the inner surface of the cylinder can be the main surface. The thickness of the polycrystalline SiC molded body varies depending on the deposition time, and can be formed to any thickness. Cylinders with diameters of approximately 5 mm to 700 mm are known.

[0005] Regarding SiC molded bodies having a specific resistivity, Patent Document 1 describes a silicon carbide body for use as a semiconductor manufacturing component, obtained by a CVD method, characterized in that the content of nitrogen element is 0.1 to 100 ppm, the content of metal elements other than silicon is 10 ppm or less, the resistivity is 0.01 to 10 Ω cm, and the variation in the resistivity is 10% or less. As a specific example, a silicon carbide body having a resistivity of 0.1 to 5 Ω cm is disclosed.

[0006] Patent Document 2 describes an independent article comprising chemically vapor deposited low resistivity silicon carbide having an electrical resistivity of less than 0.9 Ω·cm, and specifically discloses silicon carbide deposits having a resistivity of 0.25 to 0.9 Ω·cm.

[0007] Japanese Patent No. 4595153 Japanese Patent Application Laid-Open No. 2001-316821

[0008] The small grain size of the SiC compact is considered preferable because general wear occurs preferentially from the grain boundaries, leading to a reduction in particles generated during wear. Furthermore, the large grain size reduces the volume resistivity, making it suitable for use in heaters and other applications in semiconductor manufacturing equipment.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a polycrystalline SiC molded body having a low volume resistivity and in which the crystal grain size is controlled within a specific range, and a method for producing the same.

[0010] As a result of investigations, the present inventors have found that the above problems can be solved by the following means: [1] An average crystal grain size is 5.5 μm or more and 25.0 μm or less, and the nitrogen concentration is 0.27×10 20 pieces / cm 3 5.4 x 10 20 pieces / cm 3 The product of carrier density and hole mobility is 4.0×10 20 pieces / cmVsec or more 100×10 20 [2] A polycrystalline SiC molded body according to [1], having a volume resistivity of 0.0200 Ω cm or less. [3] A method for producing a polycrystalline SiC molded body according to [1], comprising the steps of: placing a substrate in a CVD reactor; heating the substrate; and introducing a mixed gas containing a source gas and a nitrogen-containing gas into the CVD reactor and depositing a polycrystalline SiC film on the heated substrate by a CVD method, wherein the deposition step is carried out under conditions of a deposition rate of 15 μm / hr to 60 μm / hr and a residence time of 10 seconds to 100 seconds.

[0011] According to the present invention, there are provided a polycrystalline SiC molded body having a low volume resistivity and in which the crystal grain size is controlled within a specific range, and a method for producing the same.

[0012] 1 is a schematic diagram showing an example of a system for manufacturing a polycrystalline SiC compact; 2 is a schematic diagram showing a modified example of a CVD reactor;

[0013] 1: Polycrystalline SiC molded body The polycrystalline SiC molded body according to the embodiment of the present invention has an average crystal grain size of 5.5 μm or more and 25.0 μm or less, and a nitrogen concentration of 0.27×10 20 pieces / cm 3 5.4 x 10 20 pieces / cm 3 The product of carrier density and hole mobility is 4.0×10 20 pieces / cmVsec or more 100×10 20 By employing such a configuration, it is possible to obtain a polycrystalline SiC molded body having a low volume resistivity in which the crystal grain size is controlled within a specific range.

[0014] In this specification, the term "average crystal grain size" refers to the "average crystal grain size" calculated by the "area fraction method" determined by EBSD (Electron Backscatter Diffraction).

[0015] According to this embodiment, the average crystal grain size is 5.5 μm or more and 25.0 μm or less, and the nitrogen concentration is 0.27×10 20 pieces / cm 3 5.4 x 10 20 pieces / cm 3 The product of carrier density and hole mobility is 4.0×10 20 pieces / cmVsec or more 100×10 20 It is possible to obtain a polycrystalline SiC molded body having a density of not more than 1 / cmVsec.

[0016] The average crystal grain size is, for example, 5.5 μm or more and 25.0 μm or less, preferably 8.0 μm or more and 20.0 μm or less, and more preferably 10.0 μm or more and 15.0 μm or less.

[0017] In this specification, "nitrogen concentration" refers to the number of nitrogen atoms per unit volume / cm3 The nitrogen concentration is determined using dynamic SIMS (Secondary Ion Mass Spectrometry).

[0018] Nitrogen concentration is 0.27 x 10 20 pieces / cm 3 5.4 x 10 20 pieces / cm 3 A sufficiently small volume resistivity can be obtained by ensuring that the nitrogen concentration is in the following range: This nitrogen concentration corresponds to 200 ppm or more and 3800 ppm or less.

[0019] Such a nitrogen concentration is considered to be extremely high for an impurity concentration doped into a polycrystalline SiC molded body, and would normally exceed the solubility limit. Adding nitrogen in an amount exceeding the solubility limit would result in the formation of compounds other than SiC, preventing the polycrystalline SiC molded body from exhibiting the desired functionality. However, according to this embodiment, the manufacturing method described below allows nitrogen to be dissolved even at such a concentration, thereby achieving the properties required for a polycrystalline SiC molded body. While the reason for achieving such properties is unclear, for example, an excessively slow film formation rate would extend the film formation time, which would similarly extend the time required for the formation of compounds other than SiC, potentially preventing the formation of a solid solution. Furthermore, an excessively fast film formation rate would likely result in the formation of SiC before the nitrogen could decompose into reactive intermediates, preventing the nitrogen solid solution reaction from occurring sufficiently.

[0020] The "product of carrier concentration x Hall mobility" is a value calculated from the "carrier density" and the "hall mobility."

[0021] The product of carrier density x Hall mobility is related to volume resistivity. According to this embodiment, the product of carrier density x Hall mobility is 4.0 x 10 20 pieces / cmVsec or more 100×10 20 The polycrystalline SiC compact preferably has a volume resistivity of 25×10 20 pieces / cmVsec or more 100×10 20particles / cmVsec or less, more preferably 35×10 20 pieces / cmVsec or more 100×10 20 The product of carrier density x hole mobility can be equal to or less than 1 / cmVsec.

[0022] "Carrier density" refers to the concentration of impurities doped into the SiC compact. The carrier density can be determined using Hall effect measurement.

[0023] For example, the carrier density is 1.0×10 19 pieces / cm 3 Above 7.0 x 10 19 pieces / cm 3 The following is the result.

[0024] "Hall mobility" is a known parameter and can be determined using Hall effect measurements. For example, the Hall mobility is 10 cm 2 / Vsec or more 150cm 2 / Vsec or less.

[0025] According to this embodiment, the polycrystalline SiC molded body can have a volume resistivity of, for example, 0.0200 Ω cm or less, preferably 0.0100 Ω cm or less, more preferably 0.0010 Ω cm or less, and even more preferably 0.0001 Ω cm or less.

[0026] In one preferred embodiment, the polycrystalline SiC compact is 3C-SiC.

[0027] In a preferred embodiment, the polycrystalline SiC molded body has a main surface. The polycrystalline SiC molded body is preferably plate-shaped, more preferably disk-shaped. When the polycrystalline SiC molded body is plate-shaped, the main surface of the polycrystalline SiC molded body refers to the front and back surfaces excluding the side surfaces. In this case, the thickness of the polycrystalline SiC molded body is, for example, 0.1 mm to 5.0 mm, preferably 0.2 mm to 3.0 mm. Furthermore, when the polycrystalline SiC molded body is disk-shaped, the diameter of the polycrystalline SiC molded body is not particularly limited, but is, for example, 100 mm to 300 mm, preferably 130 mm to 200 mm.

[0028] The polycrystalline SiC molded body may be cylindrical. In the cylindrical case, the main surface of the polycrystalline SiC molded body refers to the surface and inner surface of the cylinder. In this case, the thickness of the polycrystalline SiC molded body is, for example, 0.1 mm to 5.0 mm, preferably 0.2 mm to 3.0 mm.

[0029] In a more preferred embodiment, the primary surface has a (111) peak intensity ratio of 0.25 to 0.50. The "(111) peak intensity ratio" is a parameter that represents the ratio of the diffraction peak intensity of SiC(111) to the sum of the diffraction peak intensities of the SiC(111) plane, the SiC(200) plane, the SiC(220) plane, and the SiC(311) plane in an X-ray diffraction pattern.

[0030] 2: Method for Manufacturing Polycrystalline SiC Molded Body A polycrystalline SiC molded body having the above-described properties can be obtained by adjusting the film formation conditions, etc., in the manufacturing method described below. The method for manufacturing a polycrystalline SiC molded body according to this embodiment will be described below.

[0031] FIG. 1 is a schematic diagram showing an example of a manufacturing system used in the method for manufacturing a polycrystalline SiC compact according to this embodiment. This manufacturing system includes a CVD reactor 1 and a mixer 2. In the mixer 2, a carrier gas 6, a source gas 7 serving as a SiC supply source, and a nitrogen-containing gas 8 are mixed to generate a mixed gas. The mixed gas is supplied from the mixer 2 to the CVD reactor 1 at a flow rate Q. A substrate 3 (e.g., a graphite substrate) is placed in the CVD reactor 1. In the CVD reactor 1, the substrate 3 is heated during operation. The substrate 3 is preferably disk-shaped or rod-shaped. The CVD reactor 1 is also provided with a nozzle 4, through which the mixed gas is introduced into the CVD reactor. Once the mixed gas is introduced into the CVD reactor, a polycrystalline SiC film is formed on the heated substrate 3 by the CVD method. During this process, nitrogen from the nitrogen-containing gas is doped into the polycrystalline SiC film. That is, a nitrogen-doped polycrystalline SiC film is obtained. The substrate 3 is removed from the obtained polycrystalline SiC film, and the film is ground as necessary. This results in a polycrystalline SiC compact.

[0032] 1, a plurality of nozzles 4 are provided. The substrate 3 is arranged vertically. The plurality of nozzles 4 are provided on both sides of the furnace wall so as to sandwich the substrate 3. In FIG. 1, L is the distance between the tip of each nozzle (the outlet for the source gas) and the substrate 3.

[0033] It should be noted that the CVD reactor 1 does not necessarily have to have the configuration shown in Fig. 1. Fig. 2 is a diagram showing a modified example of the CVD reactor 1. In the example shown in Fig. 2, a plurality of nozzles 4 are provided at the top of the CVD reactor 1. The substrate 3 is placed horizontally. The CVD reactor 1 may have the configuration shown in Fig. 2.

[0034] Possible embodiments of the CVD reactor include cold-wall and hot-wall types. In a cold-wall CVD reactor, the furnace walls and the atmosphere inside the furnace are not directly heated, and only the substrate is directly heated. In a hot-wall CVD reactor, the entire furnace, including the furnace walls and the atmosphere inside the furnace, is heated. In this embodiment, there is no difference in the properties of the SiC molded body obtained using either the cold-wall or hot-wall type.

[0035] In this embodiment, the polycrystalline SiC film is formed within a specific "arrival time τ." Specifically, the formation is performed under conditions such that the arrival time τ is 0.02 seconds or more and 0.10 seconds or less.

[0036] The arrival time τ represents the time from when the mixed gas is introduced into the CVD reactor until it reaches the substrate. Specifically, the arrival time τ can be calculated according to the following formula:

[0037] Arrival time τ = L / u L: distance between the source gas outlet (nozzle tip) and the substrate u: flow rate of the mixed gas in the reactor

[0038] The flow velocity u of the mixed gas is calculated by dividing the flow rate Q by the cross-sectional area A of the nozzle.

[0039] The flow rate Q represents the flow rate of the mixed gas between the mixer and the reactor. The flow rate Q is not particularly limited, but is, for example, 10 L / min to 400 L / min, preferably 50 L / min to 350 L / min.

[0040] According to the findings of the present inventors, the arrival time τ affects the concentration of dissolved nitrogen, which in turn affects the carrier concentration and Hall mobility. Therefore, by optimizing the arrival time τ, it is possible to realize a polycrystalline SiC film having a predetermined average particle size and in which the product of the nitrogen concentration and the carrier density x Hall mobility is controlled. The arrival time τ is preferably set to 0.02 seconds or more and 0.10 seconds or less, more preferably 0.02 seconds or more and 0.08 seconds or less, and even more preferably 0.02 seconds or more and 0.06 seconds or less, in order to adjust the particle size within a preferred range.

[0041] The source gas that serves as a supply source of SiC may be a one-component system (gas containing Si and C) or a two-component system (gas containing Si and gas containing C).

[0042] For example, examples of one-component source gases include methyltrichlorosilane, trichlorophenylsilane, dichloromethylsilane, dichlorodimethylsilane, and chlorotrimethylsilane, while examples of two-component source gases include mixtures of silane-containing gases such as trichlorosilane and monosilane with hydrocarbon gases.

[0043] The nitrogen-containing gas may be any gas capable of doping nitrogen into the polycrystalline SiC film, for example, nitrogen gas.

[0044] The carrier gas used during film formation is not particularly limited, but may be, for example, hydrogen gas.

[0045] The film formation conditions other than the arrival time τ are not particularly limited, but for example, the following conditions can be adopted.

[0046] Regarding the heating temperature during film formation, the reaction temperature is, for example, 1300° C. to 1400° C., preferably 1300° C. to 1350° C. Note that the furnace walls and heat insulating materials inside the furnace are preferably kept at a temperature at which SiC and decomposition products of the source gas do not deposit (for example, 1000° C. or less, preferably 700° C. or less).

[0047] The flow rate of the nitrogen-containing gas is, for example, 5 vol% to 100 vol%, preferably 30 vol% to 50 vol%, of the total flow rate of the nitrogen-containing gas flow rate, the raw material gas flow rate, and the carrier gas flow rate.

[0048] The deposition rate is, for example, 15 μm / hr to 60 μm / hr, preferably 15 μm / hr to 40 μm / hr. By controlling the deposition rate within the above range, the average particle size and nitrogen concentration can be controlled to predetermined values.

[0049] The residence time is, for example, 10 seconds or more and 100 seconds or less, preferably 20 seconds or more and 75 seconds or less. The residence time means the time during which the mixed gas is retained in the reactor. By controlling the residence time within the above range, the average particle size can be controlled to a predetermined value.

[0050] The present invention will be described in more detail below with reference to examples. In these examples and comparative examples, the film formation time was set to 1 hour or more and 60 hours or less, and the reaction temperature was set to 1200° C. or more and 1500° C. or less.

[0051] Example 1 A CVD reactor was prepared as shown in Fig. 1. As a substrate, one graphite substrate having a diameter of 160 mm and a thickness of 5 mm was prepared and placed in the CVD reactor.

[0052] Next, a polycrystalline SiC film was formed on the substrate under the conditions shown in Table 1. Specifically, MTS (methyltrichlorosilane) was used as the source gas. H gas was used as the carrier gas. N gas was used as the nitrogen-containing gas. The source gas, carrier gas, and nitrogen-containing gas were mixed in mixer 2 to generate a mixed gas. The mixed gas was supplied into CVD reactor 1. The amount of the mixed gas supplied was the value shown as "gas amount" in Table 1. The concentrations of MTS gas, H gas, and N gas in the mixed gas were as shown in Table 1.

[0053] The residence time was 22 seconds. The residence time was calculated using the following formula.

[0054] Residence time (seconds) = (furnace volume / gas volume) x ((20 + 273) / (reaction temperature + 273)) x 60

[0055] The arrival time τ was 0.03 seconds.

[0056] After the film formation, the graphite substrate was removed from the CVD reactor and subjected to peripheral processing and division processing. The graphite substrate was then removed to obtain a polycrystalline SiC molded body having a diameter of 150 mm and a thickness of 0.6 mm. The front and back surfaces were then ground by surface grinding to obtain a polycrystalline SiC molded body having a diameter of 150 mm and a thickness of 0.4 mm. This was obtained as the polycrystalline SiC molded body of Example 1.

[0057] Examples 2 to 8 and Comparative Examples 1 to 3 Polycrystalline SiC films were formed in the same manner as in Example 1. However, the film formation conditions were changed as shown in Table 1.

[0058] (Evaluation Method) The (111) peak intensity ratio, carrier density, Hall mobility, nitrogen concentration (SIMS N concentration), average crystal grain size, and resistivity of the obtained polycrystalline SiC molded body were measured. The measurement methods for each value are described below.

[0059] (111) Peak Intensity Ratio The X-ray diffraction pattern at the center of the polycrystalline SiC compact was measured by the 2θ / θ method using an XRD-6000 manufactured by Shimadzu Corporation under the following conditions: Cu target, voltage: 40.0 kV, current: 20.0 mA, divergence slit: 1.00000 deg., scattering slit: 1.00000 deg., receiving slit: 0.30000 mm, scan range: 20.000 deg. to 80.000 deg., scan speed: 4.0000 deg. / min., sampling pitch: 0.0200 deg., preset time: 0.30 sec. Appropriate background correction was performed on the obtained X-ray diffraction pattern, and the diffraction angle 2θ was measured to be 35.3 deg. to 36.0 deg. The diffraction peak intensity in the following range was determined as the peak intensity of the SiC (111) plane of 3C-SiC.

[0060] Similarly, the diffraction peak intensity in the diffraction angle 2θ range of 41.1 degrees or more and 41.8 degrees or less was determined as the peak intensity of the SiC (200) plane.

[0061] Similarly, the diffraction peak intensity in the diffraction angle 2θ range of 59.7 degrees or more and 60.3 degrees or less was determined as the peak intensity of the SiC (220) plane.

[0062] Similarly, the diffraction peak intensity in the diffraction angle 2θ range of 71.5 degrees or more and 72.3 degrees or less was determined as the peak intensity of the SiC (311) plane.

[0063] The total value of the diffraction peak intensities of the SiC(111), SiC(200), SiC(220), and SiC(311) planes was calculated, and the ratio of the SiC(111) diffraction peak intensity to the total value was calculated as the (111) peak intensity ratio.

[0064] (Carrier Density, Hall Mobility) Using a Resistest 8200 manufactured by Toyo Corporation, the Hall voltage and VanderPauw resistivity were measured, and the carrier density and Hall mobility were calculated (Hall Effect Measurement). The Hall effect measurement was performed by cutting the sample into a size of approximately 10 mm × 10 mm × 0.5 mm, forming an In electrode, and then performing the measurement under the following conditions: Applied magnetic field: 1 T, Applied current: 1.0 × 10 -6 A Measurement temperature: room temperature (295K)

[0065] (Nitrogen Concentration) The nitrogen content in the polycrystalline SiC molded body was measured using SIMS-4000 manufactured by ATOMIKA Corporation.

[0066] (Average Crystal Grain Size) A crystal orientation map with respect to the normal direction to the main surface of the polycrystalline SiC compact was obtained by EBSD.

[0067] The measurement conditions were as follows: Pretreatment: Chemical mechanical polishing Apparatus: FE-SEM JSM-7900F EBSD manufactured by JEOL Ltd. AZtecHKL image analysis software AZtec Crystal Measurement conditions: Voltage: 20 kV Tilt angle: 70° Measurement area: 800 μm×600 μm Measurement interval: 1.4 μm Evaluation target crystal system: 3C-type SiC (space group 216) When measuring a sample with an average particle size of less than 5.5 μm under the above conditions, the analysis becomes unstable and accurate analysis results cannot be obtained, and in such cases it was determined to be "unable to evaluate."

[0068] Using the crystal orientation map measured above, the area of ​​each single region within the entire region (800 μm × 600 μm) was multiplied by the area of ​​that single region divided by the total area of ​​the observation region to obtain the average cross-sectional area of ​​the crystal grains (area fraction method). The diameter of a circle having the same area as the obtained average cross-sectional area of ​​the crystal grains was determined, and the average crystal grain size was calculated. Specifically, the average crystal grain size was calculated by analyzing using image analysis software attached to the EBSD device.

[0069] The crystal orientation map was measured at three points on the same measurement surface, the average crystal grain size was calculated for each point, and the average value of the three points was taken as the average crystal grain size for that measurement surface.

[0070] The positional relationship of each crystal orientation map was as follows: The center point of the measurement area in the first crystal orientation map was determined. The second crystal orientation map was measured using a point moved by 2000 μm or more and 4000 μm or less in any direction from that center point as the new center point. The third crystal orientation map was measured using a point moved by 2000 μm or more and 4000 μm or less from the center point of the measurement area in the second crystal orientation map as the new center point.

[0071] The measurements were carried out on the front and back surfaces, and the larger value was taken as the average crystal grain size of the sample, with the threshold value being 10°.

[0072] (Measurement of Volume Resistivity) The volume resistivity of the polycrystalline SiC molded body was measured by the four-probe method in accordance with JIS K 7194. Specifically, a Loresta GP MCP-T610 manufactured by Mitsubishi Chemical Analytech Co., Ltd. was used to measure the volume resistivity.

[0073] (Discussion of Results) As shown in Tables 1 and 2, the polycrystalline SiC molded bodies according to Examples 1 to 8 were formed under conditions in which the deposition rate was 15 μm / hr or more and 60 μm / hr or less, and the residence time was 10 seconds or more and 100 seconds or less. As shown in Table 2, the polycrystalline SiC molded bodies according to Examples 1 to 8 had low volume resistivities. In particular, Examples 2 to 8 had extremely low volume resistivities (specifically, 0.0074 Ω cm or less). The average crystal grain size of the polycrystalline SiC molded bodies according to Examples 1 to 8 was 5.5 μm or more and 25.0 μm or less, confirming that the SiC molded bodies had crystal grain sizes within a specific range. In addition, the nitrogen concentration was 0.27×10 19 pieces / cm 3 5.4 x 10 20 pieces / cm 3 The product of carrier density and hole mobility was 4.0×10 20 pieces / cmVsec or more 100×10 20 The number was less than 1 / cmVsec.

[0074] On the other hand, in Comparative Example 1 where the film formation rate was 602 μm / hr, the average particle size could not be evaluated, and the product of carrier density × Hall mobility was 3.2 × 10 20 The density / cmVsec was smaller than those of Examples 1 to 8, and the volume resistivity was also greater than 0.0200 Ω·cm.

[0075] Similarly, in Comparative Example 2, in which the deposition rate was 911 μm / hr, the average crystal grain size could not be evaluated.

[0076] In Comparative Example 3, in which the film formation rate was 10 μm / hr, the average particle size was 27.3 μm, which was larger than those of Examples 1 to 8.

[0077]

[0078]

[0079] The large crystal grain size reduces the volume resistivity, making it suitable for use as a heater or other component in semiconductor manufacturing equipment.

[0080] REFERENCE SIGNS LIST 1 CVD reactor 2 Mixer 3 Substrate 4 Nozzle 5 Flow meter 6 Carrier gas 7 Source gas 8 Nitrogen-containing gas

Claims

1. The average crystal grain size is 5.5 μm or more and 25.0 μm or less, and the nitrogen concentration is 0.27×10 20 pieces / cm 3 Above 5.4 x 10 20 pieces / cm 3 The product of carrier density and Hall mobility is 4.0×10 20 pieces / cmVsec or more 100×10 20 1. A polycrystalline SiC molded body having a surface roughness of 1 / cmVsec or less.

2. The polycrystalline SiC compact according to claim 1, having a volume resistivity of 0.0200 Ω·cm or less.

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