Polycrystalline silicon rod

Abstract

A polycrystalline silicon rod grown by deposition according to a chemical vapor deposition process, wherein the polycrystalline silicon rod has a diameter (2R) of 150 mm or more, and When an X-ray diffraction pattern obtained by in-plane rotation with a center of a plate-like sample taken from each of a central region, an R / 2 region and an outer region of the polycrystalline silicon rod as a pivot point is determined at an angle φ of 180 degrees, a degree of deviation of the diffraction intensity from a plane <220> 0.12 or less in the middle region, 0.30 or less in the R / 2 region and 0.54 or less in the outer region when evaluated as a 6σ n-1 / average value, where σ n-1 represents a standard deviation.

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a polycrystalline silicon rod suitable as a raw material for producing single-crystal silicon. Description of the state of the art

[0002] Single-crystal silicon, which is essential for manufacturing a semiconductor device and the like, is grown by a CZ method or an FZ method, and in such a case, a polycrystalline silicon rod or a polycrystalline silicon bulk is used as a raw material. Such a polycrystalline silicon material is often produced by a Siemens method. The Siemens method is a method that involves bringing a silane raw material gas of trichlorosilane, monosilane, or the like into contact with a heated silicon core, thereby growing polycrystalline silicon on the surface of the silicon core by vapor-phase epitaxy (deposition) according to a chemical vapor deposition (CVD) process.

[0003] For example, when single-crystal silicon is grown as a crystal using the CZ method, a polycrystalline silicon mass is loaded into a quartz crucible and heated and melted to form a silicon melt. A seed crystal is immersed in the silicon melt to allow a dislocation line to disappear, and then a crystal is pulled up while gradually increasing its diameter until a predetermined diameter is reached. In this process, if unmelted polycrystalline silicon remains in the silicon melt, such a piece of polycrystalline silicon drifts to the vicinity of the solid-liquid interface by convection, causing the appearance of dislocations and the disappearance of a crystal line.

[0004] Japanese patent application JP 2008-285403 A reports the following: a needle crystal can be deposited in a polycrystalline silicon rod in a step of manufacturing the rod by a Siemens method. When such a polycrystalline silicon rod is used to grow single-crystal silicon by an FZ method, a single crystallite, depending on its size, is not uniformly melted due to the heterogeneous fine structure described above. An unmelted crystallite passes into a single-crystal rod as a solid particle through a molten zone and is thus incorporated into the solidified surface of a single crystal as an unmelted particle, causing defect formation. See also Japanese patent application JP 2013-193902 A and Japanese patent application JP 2014-28747 A regarding the needle crystal.

[0005] The "needle crystal" referred to herein refers to a needle crystal whose long-axis direction corresponds to the deposition direction of the polycrystalline silicon rod (direction vertical to the long-axis direction of the polycrystalline silicon rod). The long-axis length of the needle crystal is up to several nm. Such a needle crystal is considered to be formed by integration due to the bonding of a locally heterogeneous crystal generated during the deposition of polycrystalline silicon with the progress of a deposition step. When a polycrystalline silicon rod containing such a locally heterogeneous crystal and needle crystal is used to grow single-crystal silicon by an FZ method, the locally heterogeneous crystal and needle crystal float in the silicon melt, resulting in crystal growth failure.Therefore, a growth process for a polycrystalline silicon rod is required that does not include a locally heterogeneous crystal or a needle crystal. Compared to Miller indices, a needle crystal has a crystallographic feature where <220> dominant over <111> is (the detection amount is in a <220> larger compared to the detection quantity by X-ray refraction) and <111> is dominant in a region where no needle crystal is present.

[0006] The Japanese patent application JP 2016 - 150 885 A reports the following: a locally heterogeneous crystal with a principal plane of <111> is easily generated in the central portion of a polycrystalline silicon rod (the portion closer to a core). When the crystal grain size is measured by EBSD, no information about the heterogeneity of a locally heterogeneous crystal can be obtained, even while determining the crystal orientation that forms the heterogeneous crystal, other than the external appearance of the heterogeneous crystal. The best method for detecting a locally heterogeneous crystal is a method in which etching is performed with an aqueous solution of mixed hydrofluoric acid and nitric acid and observations are made through an optical microscope.When observed at approximately 100x magnification through an optical microscope, a locally heterogeneous crystal can often be confirmed as a crystal section with a longer diameter of 10 µm or more. Japanese patent application JP 2017 - 57 093 A discloses a polycrystalline silicon rod made from monosilane that can be used for the production of single-crystal silicon. SUMMARY OF THE INVENTION

[0007] Of course, in single-crystal silicon grown in either the CZ method or the FZ method, its diameter is larger, and currently, its diameter is mainly 6 inches to 8 inches. Due to such a larger diameter, adverse effects (disappearance of a crystal line, warping or disruption of a crystal line, and the like) caused by a heterogeneous site present in a polycrystal have been remarkably generated in the single-crystalization step. Therefore, polycrystalline silicon has been increasingly demanded for use as a raw material for production in order to achieve higher crystal homogeneity than ever before. In particular, such polycrystalline silicon is required to include neither a needle crystal nor a locally heterogeneous crystal.

[0008] The present invention has been made in view of such problems, and an object thereof is therefore to provide polycrystalline silicon suitable as a raw material for producing polycrystalline silicon, resulting in contributing to stable production of single-crystal silicon.

[0009] To achieve the object, the polycrystalline silicon rod according to the present invention is a polycrystalline silicon rod grown by deposition according to a chemical vapor deposition process, wherein the polycrystalline silicon rod has a diameter (2R) of 150 mm or more, and, when an X-ray diffraction pattern obtained by in-plane rotation with a center of a plate-like sample taken from each of a central region, an R / 2 region and an outer region of the polycrystalline silicon rod as a fulcrum, at an angle φ of 180 degrees, a degree of deviation of the diffraction intensity from a plane <220> 0.12 or less in the middle region, 0.30 or less in the R / 2 region and 0.54 or less in the outer region when evaluated as a 6σ n-1 / average value, where σ n-1 represents a standard deviation.

[0010] Particularly preferably, the degree of deviation of the diffraction intensity from the plane <220> 0.09 or less in the middle region, 0.15 or less in the R / 2 region, and 0.20 or less in the outer region.

[0011] More preferably, the degree of deviation of the diffraction intensity from the plane <220> 0.08 or less in the middle region, 0.10 or less in the R / 2 region, and 0.10 or less in the outer region.

[0012] Furthermore, a method for producing a polycrystalline silicon rod is a method for producing a polycrystalline silicon rod having a diameter of 150 mm or more by depositing according to a chemical vapor deposition process, wherein a D / L value is set in the range of less than 0.40 when a plurality of pairs of silicon cores are placed in a reaction furnace and it is assumed that an average value of a final diameter of the polycrystalline silicon rod is defined as D (mm) and a mutual gap between the plurality of pairs of silicon cores is defined as L (mm).

[0013] Preferably, a reaction pressure in a deposition step of polycrystalline silicon is set to 0.2 MPa or more.

[0014] The polycrystalline silicon rod according to the present invention can be used for performing crystal growth by an FZ method and / or crystal growth by using a mass obtained from a polycrystalline silicon ingot by a CZ method, thereby enabling local generation of a partial melt residue to be suppressed to contribute to stable production of single-crystal silicon. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] They show: Fig. 1A is a view for describing a sampling example of a plate-like sample for X-ray diffraction profiling from a polycrystalline silicon rod deposited and grown according to a chemical vapor deposition process; Fig.1B is a view for describing a sampling example of a plate-like sample for X-ray diffraction profiling from a polycrystalline silicon rod deposited and grown according to a chemical vapor deposition process; Fig. 2 is a view for describing a design of an example of a measuring system for determining an X-ray diffraction profile of a plate-like sample according to a φ-scanning method; Fig. 3A is an X-ray diffraction pattern taken from a plane <220> a plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.69; Fig. 3B is an X-ray diffraction pattern taken from a plane <220> a plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.36; Fig.4A the result of an observation of the surface of the Fig. 3A through an optical microscope, which was etched with a mixed liquid of hydrofluoric acid and nitric acid; and Fig. 4B shows the result of an observation of the surface of the Fig. 3B through an optical microscope, which was etched with a mixed liquid of hydrofluoric acid and nitric acid. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Embodiments of the present invention will be described below with reference to the drawings.

[0017] The present inventors proposed an invention relating to a method for selecting a polycrystalline silicon rod for use as a raw material for producing a single-crystal silicon according to an X-ray diffraction method in Japanese Patent Application JP 2015 - 3 844 A, in view of the current state in which an advanced method for selecting polycrystalline silicon suitable as a raw material for producing a single-crystal silicon in high quantities and with high reproducibility for the purpose of stable production of single-crystal silicon with a high yield is required, and the invention was filed as Japanese Patent JP 5 947 248 B2.

[0018] The method consists in that a polycrystalline silicon rod is selected as a raw material for producing single-crystal silicon in the following case: a polycrystalline silicon rod grown by deposition according to a chemical vapor deposition process is used to take a plate-like sample, wherein the cross section perpendicular to the radial direction corresponds to a principal plane, the plate-like sample is placed in a position in which the Bragg reflection from a first plane having the Miller indices <111> is determined, plane-preserving rotation is performed at a rotation angle φ with the center of the plate-like sample as the pivot point, so that φ-scanning of the main plane of the plate-like sample is performed with an X-ray radiation area defined by a slit, a diagram is determined,which represents the dependence of the Bragg reflection intensity from the plane with Miller indices on the rotation angle (φ) of the plate-like sample, the diffraction intensity value (I, B <111> ) of a baseline is determined from the diagram, and the diffraction intensity value (I B <220> ) of a baseline from a φ-scanning diagram consisting of a second level with the Miller indices <220> is obtained in the same way, and a size ratio between the I B <111> -value and the I B <220> -value satisfies the following two conditions simultaneously.

[0019] The two conditions are as follows: Condition 1: “I B <111> and I B < 220> obtained with respect to the plate-like sample taken at a position located in the range of R / 3 or less from the center in the radial direction of the polycrystalline silicon rod having a radius R satisfy I B <111> > I B <220>" ; and condition 2: “the I B <111> -value and the I B <220> -value obtained with respect to the plate-like sample taken at a position located in the range of 2R / 3 or more and 3R / 3 or less from the center in the radial direction of the polycrystalline silicon rod having a radius R satisfy I B <111> > I B <220>" .

[0020] Since a locally heterogeneous crystal with a plane with the Miller indices <111> as the main plane, a diffraction peak is formed due to a plane with the Miller indices <111> , higher in intensity than the intensity of a base line, is observed in the φ-scanning diagram above. Similarly, since a needle crystal and a locally heterogeneous crystal forming a plane with the Miller indices <220> as the main plane, more is contained, a diffraction peak due to a plane with the Miller indices <220> , higher in intensity than the intensity of a baseline, are observed in the φ-scanning diagram above. The presence of such diffraction peaks can then be determined as the deviation of the diffraction intensity from each of the planes with the Miller indices <111> and <220> which can be evaluated from the φ-scanning diagram.Accordingly, such a deviation of the diffraction intensity, if it can be quantitatively evaluated, can be considered as an index of a degree of inclusion of each of a needle crystal and a locally heterogeneous crystal with planes with the Miller indices <111> and <220> be used as main levels.

[0021] According to studies conducted by the inventors concerned, it was found that the deviation of the diffraction intensity of a plane with the Miller indices <111> is easily generated in a place where the load is increased due to current heating during the deposition of polycrystalline silicon (mainly in the vicinity of a silicon core) and the deviation of the diffraction intensity of a plane with the Miller indices <220> is easily generated at a location where radiant heat is received from an adjacent polycrystalline silicon rod (mainly outside a silicon core).

[0022] It has already been reported by the inventors concerned (Japanese patent application JP 2016 - 150 885 A) that a locally heterogeneous crystal with a principal plane <111> easily generated in the central section of a polycrystalline silicon rod, and the deviation of the diffraction intensity of a plane with the Miller indices <111> can be suppressed by appropriately controlling the temperature setting of the central portion of a polycrystalline silicon rod.

[0023] On the contrary, a locally heterogeneous crystal with a principal plane <220> easily generated at a location where radiant heat is received from a neighboring polycrystalline silicon rod (mainly outside a polycrystalline silicon rod), and therefore it is required that radiant heat from a neighboring polycrystalline silicon rod be taken into account.

[0024] The inventors in question conducted studies on the problem of radiant heat and found that forming a needle crystal and a locally heterogeneous crystal with a main plane <220> can be effectively prevented by a D / L value set within the range of less than 0.40 when a plurality of pairs of silicon cores are placed in a reaction furnace in manufacturing a polycrystalline silicon rod having a diameter of 150 mm or more according to a chemical vapor deposition process, and it is assumed that the average value of the final diameter of a polycrystalline silicon rod is defined as D (mm), and the mutual gap between the plurality of pairs of silicon cores is defined as L (mm).

[0025] In particular, the above method can provide a polycrystalline silicon rod grown by deposition according to a chemical vapor deposition process, wherein the polycrystalline silicon rod has a diameter (2R) of 150 mm or more, and when an X-ray diffraction pattern obtained by in-plane rotation with a center of a plate-like sample taken from each of the central region, the R / 2 region and the outer region of the polycrystalline silicon rod as a fulcrum is determined at an angle φ of 180 degrees, the degree of deviation of the diffraction intensity from a plane <220> 0.15 or less in the middle region, 0.30 or less in the R / 2 region and 0.58 or less in the outer region when evaluated as a 6σ n-1 / average value. Such an assessment is here referred to as the 6σ n-1 / Average value as the degree of deviation of the diffraction intensity of a plane with the Miller indices <220> (Degree of deviation of the diffraction intensity from a plane <220> ) and σ n-1 represents the standard deviation.

[0026] In the present invention, the degree of crystal homogeneity is determined in terms of the degree of deviation of the diffraction intensity of a plane with the Miller indices <220> evaluated. The evaluation procedure is described below. [Collecting evaluation samples]

[0027] Fig. 1A and Fig.1B each illustrates a view for describing a sampling example of a plate-like sample 20 for X-ray diffraction profile measurement from a polycrystalline silicon rod 10 deposited and grown according to a chemical vapor deposition process such as the Siemens method. In the drawings, symbol 1 represents a silicon core for use in depositing polycrystalline silicon on the surface and thus producing a silicon rod. In the example, the plate-like sample 20 is sampled from each of three locations (CTR: a location closer to the silicon core 1, EDG: a location closer to the outer side of the surface of the polycrystalline silicon rod 10, R / 2: a location between CTR and EGD) to evaluate crystal homogeneity. In the example illustrated in the drawings, the plate-like sample 20 is sampled by hollowing in a direction vertical to the long axis of the polycrystalline silicon rod 10.

[0028] The diameter of the Fig. 1A is 150 mm or more, and a rod 11 having a substantial diameter of 20 mm and a substantial length of 70 mm is obtained by hollowing from the outer side of the surface of the polycrystalline silicon rod 10 in a direction vertical to the longitudinal direction of the silicon core 1.

[0029] As in Fig. 1B, plate-like samples (20 CTR , 20 EDG , 20 R / 2 ), each having a cross-section perpendicular to the radial direction of the polycrystalline silicon rod 10 as a principal plane and having a substantial thickness of 2 mm, taken from the position (CTR) closer to the silicon core 1 of the rod 11, the position (EDG) closer to the side surface of the polycrystalline silicon rod 10, and the position (R / 2) between CTR and EGD, respectively.

[0030] The location, length, and number of samples for sampling the rod 11 may be appropriately determined depending on the diameter of the silicon rod 10 and the diameter of the rod 11 obtained by hollowing, and the plate-like samples 20 may also be taken from any location of the rod 11 obtained by hollowing, but such a location preferably corresponds to one that allows the characteristics of the entire silicon rod 10 to be appropriately assumed.

[0031] A case where the diameter of the plate-like sample 20 is essentially 20 mm is only an example, and the diameter can be reasonably defined as long as X-ray diffraction measurements are not hindered. To observe the crystalline structure through an optical microscope, the surface of the plate-like sample 20 can be subjected to lapping and polishing followed by etching with a mixed liquid of hydrofluoric acid and nitric acid. [X-ray diffraction pattern]

[0032] Fig.2 is a view for schematically describing a measurement system example when determining the X-ray diffraction profile of a plate-like sample 20 according to a φ scanning method. In the example shown in the drawing, an elongated rectangular area defined by a slit in an area across both peripheral ends of the plate-like sample 20 is irradiated with X-rays, and rotation in the YZ direction (φ = 0° to 180°) is performed with the center of the plate-like sample 20 as the fulcrum, so that scanning of the entire surface of the plate-like sample 20 is performed with the region irradiated with X-rays. The plate-like sample 20 is set at an angle that allows the diffraction intensity of a plane <220> is won.X-ray beam 40 (Cu-Kα ray: wavelength: 1.54 Å) emitted through a slit 30 and collimated, enters the plate-like sample 20, and the intensity of the X-ray beam diffracted with respect to the rotation angle (θ) of each sample is detected by a detector (not shown) with rotation of the plate-like sample 20 on a YZ plane (φ-scanning measurement) to provide an X-ray diffraction pattern (φ-scanning pattern).

[0033] Fig. 3A and Fig. 3B each represent an example of the X-ray diffraction pattern obtained according to the method above, and Fig. Figure 3A shows an X-ray diffraction pattern taken from a plane <220> a plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.69, and Fig.Figure 3B shows an X-ray diffraction pattern taken from a plane <220> a plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.36 when a plurality of pairs of silicon cores are placed in a reaction furnace and it is assumed that an average value of a final diameter of the polycrystalline silicon rod is defined as D (mm) and the mutual gap between the plurality of pairs of silicon cores is defined as L (mm).

[0034] In the X-ray diffraction pattern in Fig. 3A, a large number of diffraction peaks are observed from a plane with the Miller indices <220> whose intensity is higher than the intensity of a baseline. On the contrary, in the X-ray diffraction pattern in Fig.3B no diffraction peaks from a plane with the Miller indices <220> observed whose intensity is higher than the intensity of a baseline. The results indicate that, while the plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.69 comprises a needle crystal and a locally heterogeneous crystal forming a plane with the Miller indices <220> as the main plane in high number, the plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.36 hardly includes a needle crystal and a locally heterogeneous crystal having a plane with the Miller indices <220> as the main level in.

[0035] Fig. 4A and Fig.Figure 4B shows the results of observation of the surfaces of such plate-like samples etched with a mixed liquid of hydrofluoric acid and nitric acid through an optical microscope. While a needle crystal and a locally heterogeneous crystal are observed in high numbers in the plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.69 ( Fig. 4A), no such heterogeneous portion is observed in the plate-like sample taken from a polycrystalline silicon rod grown under a condition of a D / L value of 0.36 ( Fig. 4B). Examples

[0036] Several pairs of silicon cores were placed in a reaction furnace, and a polycrystalline silicon rod was grown using a Siemens process. The average diameter D after the deposition step of the polycrystalline silicon rod was adjusted within the range of 150 to 300 mm. The mutual gap L (mm) between the several pairs of silicon cores was adjusted by changing the mutual distance between the centers of each connecting two electrodes in which the two lower ends of the silicon cores were accommodated. The reaction furnace had an inner diameter of 1.8 m and a height of 3 m. The concentration of trichlorosilane gas as the raw material of polycrystalline silicon was 30 vol%, and the flow rate of hydrogen gas for dilution was 100 Nm³. 3 / Hour.

[0037] The evaluation results of the polycrystalline silicon rod in each of Examples 1 to 9 and Comparative Examples 1 to 5 were summarized in Table 1 and Table 2. The description "locally heterogeneous crystal" in the tables refers to one confirmed as a locally heterogeneous portion having a grain size of 10 μm or more on an etched surface obtained by etching the surface of a plate-like sample taken so that the direction vertical to the long axis direction of the polycrystalline silicon rod corresponded to the direction of the principal plane with a mixed liquid of hydrofluoric acid and nitric acid. [Table 1] Comparison example Example 1 2 3 1 2 3 4 D / L 0,90 0,69 0,42 0,40 0,36 0,25 0,11 Reaction pressure (MPa) 0,45 Needle crystal position Outside Observed Observed Observed Unobserved Unobserved Unobserved Unobserved R / 2 Observed Observed Observed Unobserved Unobserved Unobserved Unobserved center Unobserved Unobserved Unobserved Unobserved Unobserved Unobserved Unobserved Locally heterogeneous crystal position Outside Observed Observed Observed Unobserved Unobserved Unobserved Unobserved R / 2 Observed Observed Observed Unobserved Unobserved Unobserved Unobserved center Observed Observed Unobserved Unobserved Unobserved Unobserved Unobserved Deviation of the diffraction intensity from <220> (6σ n-1 / Ave.) position Outside 1,08 1,10 0,58 0,54 0,40 0,20 0,10 R / 2 1,00 0,60 0,30 0,30 0,20 0,15 0,10 center 0,40 0,20 0,15 0,12 0,10 0,09 0,08 Surface temperature (°C) position Outside 1091 1088 1085 1084 1082 1082 1081 R / 2 1055 1053 1051 1050 1048 1048 1048 center 1030 1028 1025 1023 1021 1020 1020 Disappearance of the FZ crystal line Observedornotobserved Observed Observed Observed Unobserved Unobserved Unobserved Unobserved [Table 2] Comparison example Example 4 5 5 6 7 8 9 D / L 0,36 Reaction pressure (MPa) 0,05 0,1 0,2 0,3 0,45 0,6 0,9 Locally heterogeneous crystal Outside Observed Observed Unobserved Unobserved Unobserved Unobserved Unobserved R / 2 Observed Observed Unobserved Unobserved Unobserved Unobserved Unobserved center Observed Observed Unobserved Unobserved Unobserved Unobserved Unobserved

[0038] The surface temperature shown in Table 1 is a value measured with a radiation thermometer in the middle section in the height direction and is only a reference value.

[0039] From the results shown in Table 1, it was found that the polycrystalline silicon rod in each of Examples 1 to 4 reduced the degree of deviation of the diffraction intensity from a plane <220> , in evaluation as the 6σ n-1 / average value to satisfy 0.15 or less in the middle region, 0.30 or less in the R / 2 region, and 0.58 or less in the outer region, showed crystal homogeneity, and was not observed to cause disappearance of a crystal line even when used as a raw material for single crystallization by an FZ method.

[0040] In addition, since the D / L value was smaller, the degree of deviation of the diffraction intensity from a plane <220> also lower. In particular, the polycrystalline silicon rod in Example 2 allowed the degree of deviation of the diffraction intensity from a plane <220> to meet 0.12 or less in the middle region, 0.30 or less in the R / 2 region and 0.54 or less in the outer region, the polycrystalline silicon rod in Example 3 allowed the degree of deviation of the diffraction intensity from a plane <220> to satisfy 0.09 or less in the central region, 0.15 or less in the R / 2 region, and 0.20 or less in the outer region, and the polycrystalline silicon rod in Example 4 enabled the degree of deviation of the diffraction intensity from a plane <220> to meet 0.08 or less in the middle region, 0.10 or less in the R / 2 region, and 0.10 or less in the outer region.

[0041] In contrast, the polycrystalline silicon rod in each of the comparative examples did not allow any degree of deviation of the diffraction intensity from a plane <220> , in evaluation as the 6σ n-1 / average value to satisfy the condition of “0.12 or less in the central region, 0.30 or less in the R / 2 region, and 0.54 or less in the outer region,” and it was observed that when used as a raw material for single crystallization by an FZ method, it caused disappearance of a crystal line.

[0042] From the results shown in Table 2, it was found that high crystal homogeneity was achieved when the reaction pressure in the polycrystalline silicon deposition step was set to 0.2 MPa or above. Industrial applicability

[0043] The present invention provides polycrystalline silicon suitable as a raw material for producing single-crystal silicon, thereby contributing to stable production of single-crystal silicon.

Claims

[1] Polycrystalline silicon rod grown by deposition according to a chemical vapor deposition process, wherein the polycrystalline silicon rod has a diameter (2R) of 150 mm or more, and When an X-ray diffraction pattern obtained by in-plane rotation with a center of a plate-like sample taken from each of a central region, an R / 2 region and an outer region of the polycrystalline silicon rod as a pivot point is determined at an angle φ of 180 degrees, a degree of deviation of the diffraction intensity from a plane <220> 0.12 or less in the middle region, 0.30 or less in the R / 2 region and 0.54 or less in the outer region when evaluated as a 6σ n-1 / average value, where σ n-1 represents a standard deviation. [2] The polycrystalline silicon rod according to claim 1, wherein the degree of deviation of the diffraction intensity from the plane <220> 0.09 or less in the middle region, 0.15 or less in the R / 2 region, and 0.20 or less in the outer region. [3] The polycrystalline silicon rod according to claim 1, wherein the degree of deviation of the diffraction intensity from the plane <220> 0.08 or less in the middle region, 0.10 or less in the R / 2 region, and 0.10 or less in the outer region.

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