JP6459406B2 - Silicon carbide single crystal manufacturing apparatus and silicon carbide single crystal manufacturing method - Google Patents

Description

  The present invention relates to a silicon carbide single crystal manufacturing apparatus and a silicon carbide single crystal manufacturing method.

  In recent years, in order to enable a semiconductor device to have a high breakdown voltage and a low loss, silicon carbide is being adopted as a material constituting the semiconductor device.

  JP-T-2012-510951 (Patent Document 1) describes a method of producing a silicon carbide single crystal by a sublimation method using a graphite crucible. A resistance heater is provided on each of the upper and lower sides of the crucible.

Special table 2012-510951 gazette

  An object of one embodiment of the present invention is to provide a silicon carbide single crystal manufacturing apparatus and a silicon carbide single crystal manufacturing method capable of improving crystal quality.

  A silicon carbide single crystal manufacturing apparatus according to one embodiment of the present invention includes a crucible and a resistance heater. The crucible has a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface. The resistance heater is configured to surround the side surface. The resistance heater includes a first portion that extends along a direction from the top surface toward the bottom surface, a second portion that is provided continuously with the first portion on the bottom surface side, and extends along the circumferential direction of the side surface. A third portion provided continuously with the second portion and extending along a direction from the bottom surface toward the top surface, and provided continuously with the third portion on the top surface side and in a circumferential direction of the side surface. And a fourth portion extending along. The resistance heater is configured such that the difference between the maximum temperature and the minimum temperature of the resistance heater is 100 ° C. or less at a certain temperature between the average temperature of the resistance heater and 2000 ° C. or more and 2400 ° C. or less.

A silicon carbide single crystal manufacturing apparatus according to one embodiment of the present invention includes a crucible and a resistance heater. The crucible has a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface. The resistance heater is configured to surround the side surface. The resistance heater includes a first portion that extends along a direction from the top surface toward the bottom surface, a second portion that is provided continuously with the first portion on the bottom surface side, and extends along the circumferential direction of the side surface. A third portion provided continuously with the second portion and extending along a direction from the bottom surface toward the top surface, and provided continuously with the third portion on the top surface side and in a circumferential direction of the side surface. And a fourth portion extending along. The resistance heater is configured such that the difference between the maximum temperature and the minimum temperature of the resistance heater is 100 ° C. or less at a certain temperature between the average temperature of the resistance heater and 2000 ° C. or more and 2400 ° C. or less. The first portion has a first surface facing the third portion and a second surface opposite to the first surface. The third portion has a third surface facing the first surface and a fourth surface opposite to the third surface. The second portion has a fifth surface located between the first surface and the third surface, and a sixth surface opposite to the fifth surface. The distance between the second surface and the fourth surface in the circumferential direction is a, the distance between the first surface and the third surface in the circumferential direction is b, and the fifth surface and the sixth surface in the direction from the top surface to the bottom surface Where c ≧ and the radius of curvature of the fifth surface when viewed along the direction perpendicular to the side surface is r, a ≧ 3b, c ≧ b, and r ≧ b / 2. The resistance heater is made of carbon. The density of carbon is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less, and the resistivity of carbon is 1200 μΩ · cm or more.

  A method for manufacturing a silicon carbide single crystal according to one embodiment of the present invention includes the following steps. A crucible having a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface, a resistance heater configured to surround the side surface, and provided inside the crucible A prepared raw material and a seed crystal provided facing the raw material inside the crucible are prepared. A silicon carbide single crystal grows on the seed crystal by sublimating the raw material with a resistance heater. In the step of growing the silicon carbide single crystal, the difference between the maximum temperature and the minimum temperature of the resistance heater is maintained at 100 ° C. or less.

  A method for manufacturing a silicon carbide single crystal according to one embodiment of the present invention includes the following steps. A crucible having a chamber, a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface; and a crucible provided in the chamber And a resistance heater configured to surround the side surface, a raw material provided inside the crucible, and a seed crystal provided facing the raw material inside the crucible are prepared. A silicon carbide single crystal grows on the seed crystal by sublimating the raw material with a resistance heater. In the step of growing the silicon carbide single crystal, the average temperature of the resistance heater is 2000 ° C. or more and 2400 ° C. or less, the difference between the maximum temperature and the minimum temperature of the resistance heater is maintained at 100 ° C. or less, and the pressure in the chamber is It is maintained at 0.5 kPa or more and 2 kPa or less.

  According to the above, a silicon carbide single crystal manufacturing apparatus and a silicon carbide single crystal manufacturing method capable of improving the crystal quality can be provided.

It is a longitudinal cross-sectional schematic diagram which shows the structure of the manufacturing apparatus of the silicon carbide single crystal which concerns on embodiment of this invention. It is a plane schematic diagram which shows the structure of a 2nd resistance heater and an electrode. It is a perspective schematic diagram which shows the structure of a 2nd resistance heater. It is a side surface schematic diagram which shows the structure of the 2nd resistance heater along the circumferential direction. It is a side surface schematic diagram which shows the unit shape of the resistance heater model used for thermal analysis simulation. FIG. 5 is a schematic cross-sectional view taken along the line VI-VI in FIG. 1, and is a schematic cross-sectional view showing a configuration of a first resistance heater and electrodes. It is an arrow cross-sectional schematic diagram along the VII-VII line of FIG. 1, and is a cross-sectional schematic diagram which shows the structure of a 3rd resistance heater and an electrode. It is a flowchart which shows the manufacturing method of the silicon carbide single crystal which concerns on embodiment of this invention. It is a longitudinal cross-sectional schematic diagram which shows the 1st process of the manufacturing method of the silicon carbide single crystal which concerns on embodiment of this invention. It is a longitudinal cross-sectional schematic diagram which shows the 2nd process of the manufacturing method of the silicon carbide single crystal which concerns on embodiment of this invention. It is a figure which shows the relationship between the temperature of a crucible, and time. It is a figure which shows the relationship between the pressure in a chamber, and time. It is a functional block diagram which shows the method of performing feedback control of the electric power supplied to a resistance heater.

[Description of Embodiment of the Present Invention]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In the crystallographic description in this specification, the individual orientation is indicated by [], the collective orientation is indicated by <>, the individual plane is indicated by (), and the collective plane is indicated by {}. As for the negative index, “−” (bar) is attached on the number in crystallography, but in this specification, a negative sign is attached before the number.

  When a silicon carbide single crystal is grown by a sublimation method, for example, a silicon carbide raw material is sublimated by a resistance heater to generate a silicon carbide gas, and the silicon carbide gas is recrystallized on a seed crystal.

  (1) A silicon carbide single crystal manufacturing apparatus according to one embodiment of the present invention includes a crucible and a resistance heater. The crucible has a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface. The resistance heater is configured to surround the side surface. The resistance heater includes a first portion that extends along a direction from the top surface toward the bottom surface, a second portion that is provided continuously with the first portion on the bottom surface side, and extends along the circumferential direction of the side surface. A third portion provided continuously with the second portion and extending along a direction from the bottom surface toward the top surface, and provided continuously with the third portion on the top surface side and in a circumferential direction of the side surface. And a fourth portion extending along. The resistance heater is configured such that the difference between the maximum temperature and the minimum temperature of the resistance heater is 100 ° C. or less at a certain temperature between the average temperature of the resistance heater and 2000 ° C. or more and 2400 ° C. or less. Thereby, the crystal quality of the silicon carbide single crystal can be improved.

  (2) Preferably, in the silicon carbide single crystal manufacturing apparatus according to (1), the first portion has a first surface facing the third portion and a second surface opposite to the first surface. The third portion has a third surface facing the first surface and a fourth surface opposite to the third surface. The second portion has a fifth surface located between the first surface and the third surface, and a sixth surface opposite to the fifth surface. The distance between the second surface and the fourth surface in the circumferential direction is a, the distance between the first surface and the third surface in the circumferential direction is b, and the fifth surface and the sixth surface in the direction from the top surface to the bottom surface Where c ≧ and the radius of curvature of the fifth surface when viewed along the direction perpendicular to the side surface is r, a ≧ 3b, c ≧ b, and r ≧ b / 2. Thereby, it can suppress that the temperature of a resistance heater rises locally.

(3) Preferably, in the silicon carbide single crystal manufacturing apparatus according to (1) or (2), the resistance heater is made of carbon, and the density of the carbon is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less.

(4) In the silicon carbide single crystal manufacturing apparatus according to (1) or (2), preferably, the resistance heater is made of carbon, and the resistivity of the carbon is 1200 μΩ · cm or more.

(5) A silicon carbide single crystal manufacturing apparatus according to one embodiment of the present invention includes a crucible and a resistance heater. The crucible has a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface. The resistance heater is configured to surround the side surface. The resistance heater includes a first portion that extends along a direction from the top surface toward the bottom surface, a second portion that is provided continuously with the first portion on the bottom surface side, and extends along the circumferential direction of the side surface. A third portion provided continuously with the second portion and extending along a direction from the bottom surface toward the top surface, and provided continuously with the third portion on the top surface side and in a circumferential direction of the side surface. And a fourth portion extending along. The resistance heater is configured such that the difference between the maximum temperature and the minimum temperature of the resistance heater is 100 ° C. or less at a certain temperature between the average temperature of the resistance heater and 2000 ° C. or more and 2400 ° C. or less. The first portion has a first surface facing the third portion and a second surface opposite to the first surface. The third portion has a third surface facing the first surface and a fourth surface opposite to the third surface. The second portion has a fifth surface located between the first surface and the third surface, and a sixth surface opposite to the fifth surface. The distance between the second surface and the fourth surface in the circumferential direction is a, the distance between the first surface and the third surface in the circumferential direction is b, and the fifth surface and the sixth surface in the direction from the top surface to the bottom surface Where c ≧ and the radius of curvature of the fifth surface when viewed along the direction perpendicular to the side surface is r, a ≧ 3b, c ≧ b, and r ≧ b / 2. The resistance heater is made of carbon. The density of carbon is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less, and the resistivity of carbon is 1200 μΩ · cm or more. Thereby, the crystal quality of the silicon carbide single crystal can be improved.

  (6) The manufacturing method of the silicon carbide single crystal which concerns on 1 aspect of this invention is equipped with the following processes. A crucible having a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface, a resistance heater configured to surround the side surface, and provided inside the crucible A prepared raw material and a seed crystal provided facing the raw material inside the crucible are prepared. A silicon carbide single crystal grows on the seed crystal by sublimating the raw material with a resistance heater. In the step of growing the silicon carbide single crystal, the difference between the maximum temperature and the minimum temperature of the resistance heater is maintained at 100 ° C. or less. Thereby, the crystal quality of the silicon carbide single crystal can be improved.

  (7) Preferably in the manufacturing method of the silicon carbide single crystal which concerns on said (6), in the process of growing a silicon carbide single crystal, the average temperature of a resistance heater is maintained at 2000 degreeC or more and 2400 degrees C or less.

  (8) Preferably in the manufacturing method of the silicon carbide single crystal which concerns on said (6) or (7), Preferably, the process of preparing the chamber which accommodates a crucible is further provided. In the step of growing the silicon carbide single crystal, the pressure in the chamber is maintained at 0.5 kPa or more and 2 kPa or less.

(9) The manufacturing method of the silicon carbide single crystal which concerns on 1 aspect of this invention is equipped with the following processes. A crucible having a chamber, a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface; and a crucible provided in the chamber And a resistance heater configured to surround the side surface, a raw material provided inside the crucible, and a seed crystal provided facing the raw material inside the crucible are prepared. A silicon carbide single crystal grows on the seed crystal by sublimating the raw material with a resistance heater. In the step of growing the silicon carbide single crystal, the average temperature of the resistance heater is 2000 ° C. or more and 2400 ° C. or less, the difference between the maximum temperature and the minimum temperature of the resistance heater is maintained at 100 ° C. or less, and the pressure in the chamber is It is maintained at 0.5 kPa or more and 2 kPa or less. Thereby, the crystal quality of the silicon carbide single crystal can be improved.
[Details of the embodiment of the present invention]
The configuration of silicon carbide single crystal manufacturing apparatus 100 according to an embodiment of the present invention will be described.

  As shown in FIG. 1, silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment is an apparatus for manufacturing a silicon carbide single crystal by a sublimation method, and includes crucible 5 and first resistance heater 1. And a second resistance heater 10, a third resistance heater 3, a chamber 6, a lower radiation thermometer 9a, a side radiation thermometer 9b, and an upper radiation thermometer 9c. A heat insulating material may be provided between each of the first resistance heater 1, the second resistance heater 2, and the third resistance heater 3 and the chamber 6. The crucible 5 has a top surface 5a1, a bottom surface 5b2 opposite to the top surface 5a1, and a cylindrical side surface 5b1 located between the top surface 5a1 and the bottom surface 5b2. Side surface 5b1 has, for example, a cylindrical shape. The crucible 5 includes a pedestal 5 a configured to hold the seed crystal 11 and a storage portion 5 b configured to store the silicon carbide raw material 12. The pedestal 5a has a seed crystal holding surface 5a2 in contact with the back surface 11a of the seed crystal 11, and a top surface 5a1 opposite to the seed crystal holding surface 5a2. The pedestal 5a constitutes the top surface 5a1. The accommodating part 5b comprises the bottom face 5b2. The side surface 5b1 is composed of a pedestal 5a and an accommodating portion 5b. In the crucible 5, the silicon carbide raw material 12 is sublimated and recrystallized on the surface 11 b of the seed crystal 11, whereby a silicon carbide single crystal grows on the surface 11 b of the seed crystal 11. That is, the silicon carbide single crystal is configured to be manufactured by a sublimation method.

  Each of the first resistance heater 1, the second resistance heater 10, and the third resistance heater 3 is provided outside the crucible 5. The first resistance heater 1 is provided to face the bottom surface 5 b 2 of the crucible 5. The first resistance heater 1 is separated from the bottom surface 5b2. The first resistance heater 1 has an upper surface 1a facing the bottom surface 5b2 and a lower surface 1b opposite to the upper surface 1a. The second resistance heater 10 is configured to surround the side surface 5b1. The second resistance heater 10 is separated from the side surface 5b1. The second resistance heater has a tenth surface 4x1 located on the top surface 5a1 side, a sixth surface 2x2 located on the bottom surface 5b2 side, and an inner peripheral surface facing the side surface 5b1 in the direction from the bottom surface 5b2 to the top surface 5a1. 10a and an outer peripheral surface 10b opposite to the inner peripheral surface 10a. Preferably, the sixth surface 2x2 of the second resistance heater 10 is located between the bottom surface 5b2 and the top surface 5a1 in the direction from the top surface 5a1 to the bottom surface 5b2. The third resistance heater 3 is provided to face the top surface 5a1. The third resistance heater 3 is separated from the top surface 5a1.

  The lower radiation thermometer 9a is provided outside the chamber 6 at a position facing the bottom surface 5b2 of the crucible 5, and is configured to be able to measure the temperature of the bottom surface 5b2 through the window 6a. The lower radiation thermometer 9a may be provided at a position facing the first resistance heater 1, and may be configured to be able to measure the temperature of the first resistance heater 1. The side radiation thermometer 9b is provided at a position facing the side surface 5b1 outside the chamber 6, and is configured to be able to measure the temperature of the side surface 5b1 through the window 6b. The side radiation thermometer 9b is provided at a position facing the second resistance heater 10, and may be configured to be able to measure the temperature of the second resistance heater 10. The upper radiation thermometer 9c is provided at a position facing the top surface 5a1 outside the chamber 6, and is configured to be able to measure the temperature of the top surface 5a1 through the window 6c. The upper radiation thermometer 9c may be provided at a position facing the third resistance heater 3, and may be configured to be able to measure the temperature of the third resistance heater 3.

  As the radiation thermometers 9a, 9b, 9c, for example, a pyrometer (model number: IR-CAH8TN6) manufactured by Chino Co., Ltd. can be used. The measurement wavelength of the pyrometer is, for example, 1.55 μm and 0.9 μm. The emissivity setting value of the pyrometer is, for example, 0.9. The distance coefficient of the pyrometer is 300, for example. The measurement diameter of the pyrometer is obtained by dividing the measurement distance by the distance coefficient. For example, when the measurement distance is 900 mm, the measurement diameter is 3 mm.

  As shown in FIG. 2, when viewed along the direction from the top surface 5a1 to the bottom surface 5b2, the second resistance heater 10 is provided so as to surround the side surface 5b1 and has a ring shape. A set of electrodes 7 is provided in contact with the outer peripheral surface 10 b of the second resistance heater 10. When viewed along a direction perpendicular to the top surface 5a1, the pair of electrodes 7 and the top surface 5a1 may be provided on a straight line. A second power source 7 a is connected to the set of electrodes 7. The second power source 7 a is configured to be able to supply power to the second resistance heater 10. Preferably, the second resistance heater 10 constitutes a parallel circuit.

  As shown in FIGS. 1, 3 and 4, the second resistance heater 10 includes a first portion 1x extending along a direction from the top surface 5a1 to the bottom surface 5b2, and a first portion 1x on the bottom surface 5b2 side. A second portion 2x extending continuously along the circumferential direction of the side surface 5b1, and a second portion 2x extending continuously along the direction from the bottom surface 5b2 toward the top surface 5a1. The third portion 3x that is present and the fourth portion 4x that is provided continuously with the third portion 3x on the top surface 5a1 side and that extends along the circumferential direction of the side surface 5b1. The first part 1x, the second part 2x, the third part 3x, and the fourth part 4x constitute the heater unit 10x.

  Similarly, the second resistance heater 10 is provided continuously with the fourth portion 4x on the top surface 5a1 side, and extends along the direction from the top surface 5a1 toward the bottom surface 5b2, and the bottom surface 5b2. The sixth portion 2y is provided continuously with the fifth portion 1y on the side, and extends along the circumferential direction of the side surface 5b1, and is continuously provided with the sixth portion 2y, and from the bottom surface 5b2 to the top surface 5a1. It has the 7th part 3y extended along the direction to go, and the 8th part 4y provided continuously with the 7th part 3y in the top surface 5a1 side, and extended along the circumferential direction of the side surface 5b1. The fifth part 1y, the sixth part 2y, the seventh part 3y, and the eighth part 4y constitute the heater unit 10y. The second resistance heater 10 is formed in an annular shape by continuously providing a plurality of heater units 10x and 10y.

  The first portion 1x of the second resistance heater 10 has a first surface 1x1 facing the third portion 3x and a second surface 1x2 opposite to the first surface 1x1. The third portion 3x has a third surface 3x1 that faces the first surface 1x1, and a fourth surface 3x2 opposite to the third surface 3x1. The second portion 2x has a fifth surface 2x1 located between the first surface 1x1 and the third surface 3x1, and a sixth surface 2x2 opposite to the fifth surface 2x1. The fifth surface 2x1 is provided so as to connect the first surface 1x1 and the third surface 3x1. The distance between the second surface 1x2 and the fourth surface 3x2 in the circumferential direction is a, the distance between the first surface 1x1 and the third surface 3x1 in the circumferential direction is b, and the fifth in the direction from the top surface 5a1 to the bottom surface 5b2. When the shortest distance between the surface 2x1 and the sixth surface 2x2 is c and the curvature radius of the fifth surface 2x1 when viewed along the direction perpendicular to the side surface 5b1 is r, a ≧ 3b C ≧ b and r ≧ b / 2. The distance a is, for example, not less than 50 mm and not more than 60 mm. The distance b is, for example, not less than 10 mm and not more than 15 mm. The shortest distance c is, for example, 15 mm or more and 25 mm or less. The curvature radius r is, for example, 5 mm or more and 10 mm or less.

  The fifth portion 1y of the second resistance heater 10 has a seventh surface 1y2 facing the third portion 3x and an eighth surface 1y1 opposite to the seventh surface 1y2. The fourth portion 4x has a ninth surface 4x2 located between the fourth surface 3x2 and the seventh surface 1y2, and a tenth surface 4x1 opposite to the ninth surface 4x2. The ninth surface 4x2 is provided so as to connect the fourth surface 3x2 and the seventh surface 1y2. The distance between the second surface 1x2 and the fourth surface 3x2 in the circumferential direction is substantially the same as the distance between the third surface 3x1 and the eighth surface 1y1 in the circumferential direction. The distance between the first surface 1x1 and the third surface 3x1 in the circumferential direction is substantially the same as the distance between the fourth surface 3x2 and the seventh surface 1y2 in the circumferential direction. The shortest distance between the fifth surface 2x1 and the sixth surface 2x2 in the direction from the top surface 5a1 to the bottom surface 5b2 is substantially the shortest distance between the ninth surface 4x2 and the tenth surface 4x1 in the direction from the top surface 5a1 to the bottom surface 5b2. The same. The curvature radius of the fifth surface 2x1 when viewed along the direction perpendicular to the side surface 5b1 is substantially the same as the curvature radius of the ninth surface 4x2 when viewed along the direction perpendicular to the side surface 5b1. is there.

  Each of the fifth surface 2x1 and the ninth surface 4x2 is a curved surface. When viewed along a direction perpendicular to the side surface 5b1, each of the fifth surface 2x1 and the ninth surface 4x2 is, for example, a semicircle. The distance between the fifth surface 2x1 and the sixth surface 2x2 in the direction from the top surface 5a1 to the bottom surface 5b2 is minimum near the intermediate position between the first portion 1x and the third portion 3x in the circumferential direction. Similarly, the distance between the ninth surface 4x2 and the tenth surface 4x1 in the direction from the top surface to the bottom surface is minimum near the intermediate position between the third portion 3x and the fifth portion 1y in the circumferential direction.

  When the average temperature of the second resistance heater 10 is between 2000 ° C. and 2400 ° C., the second resistance heater 10 is set so that the difference between the maximum temperature and the minimum temperature of the second resistance heater 10 is 100 ° C. or less. It is configured. That is, the average temperature of the second resistance heater 10 is 2000 ° C. or more and 2400 ° C. or less at a certain time, and the difference between the maximum temperature and the minimum temperature in the temperature distribution of the second resistance heater 10 at that time is 100 ° C. or less. It has become. Preferably, the difference between the maximum temperature and the minimum temperature of the second resistance heater 10 is 95 ° C. or less, more preferably 90 ° C. or less, further preferably 85 ° C. or less, and further preferably 80 ° C. or less. is there. The maximum temperature and the minimum temperature of the second resistance heater 10 can be obtained by, for example, thermal analysis simulation. As a thermal analysis program used for the thermal analysis simulation, for example, STAR-CCM + (registered trademark) manufactured by IDAJ Co., Ltd. can be used. As shown in FIG. 5, for example, a shape model of the heater unit 10 x is produced, and the model is divided into a plurality of mesh regions M. The size of the mesh region M is, for example, 0.5 mm. The maximum temperature of the second resistance heater 10 is obtained as the temperature of the region that is the highest temperature among all the mesh regions M constituting the model. Similarly, the minimum temperature of the second resistance heater 10 is obtained as the temperature of the region that is the lowest temperature among all the mesh regions M that constitute the model. The average temperature of the 2nd resistance heater 10 is calculated | required as an average temperature of all the mesh area | regions M which comprise the said model.

  The temperature of each of the mesh regions M is calculated using the above thermal analysis program. As a result of thermal analysis simulation, it has been found that the temperature in the region including the fifth surface 2x1 of the second portion 2x and the region including the ninth surface 4x2 of the fourth portion 4x tends to be higher than the average temperature. Therefore, by setting the fifth surface 2x1 of the second portion 2x and the ninth surface 4x2 of the fourth portion 4x as curved surfaces, the temperature of the fifth surface 2x1 of the second portion 2x and the ninth surface 4x2 of the fourth portion 4x can be reduced. It can suppress becoming high. Preferably, the curvature radius r of each of the fifth surface 2x1 and the ninth surface 4x2 is not less than 5 mm and not more than 20 mm.

Preferably, the second resistance heater 10 is made of carbon. The density of carbon is, for example, 1.6 g / cm ³ or more and 2.0 g / cm ³ or less, and preferably 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon is, for example, 1100 μΩ · cm or more and 1800 μΩ · cm or less, preferably 1200 μΩ · cm or more and 1700 μΩ · cm or less.

  As shown in FIG. 6, when viewed along the direction from the top surface 5 a 1 to the bottom surface 5 b 2, the first resistance heater 1 has a shape in which two curves moving away from the center merge at the center. Preferably, the first resistance heater 1 has a Fermat spiral shape. A set of electrodes 8 is connected to both ends of the first resistance heater 1. A first power supply 8 a is connected to the set of electrodes 8. The first power supply 8 a is configured to be able to supply power to the first resistance heater 1. When viewed along a direction parallel to the bottom surface 5b2, the width W1 of the first resistance heater 1 is larger than the width W2 inside the crucible 5 (see FIG. 1), and preferably is larger than the width of the bottom surface 5b2. large. The width W1 of the first resistance heater 1 is measured so as not to include the electrode 8.

  As shown in FIG. 7, when viewed along the direction from the top surface 5 a 1 to the bottom surface 5 b 2, the third resistance heater 3 has a shape in which two curves that move away from the center merge at the center. Preferably, the third resistance heater 3 has a Fermat spiral shape. A pair of electrodes 14 is connected to both ends of the third resistance heater 3. A third power source 14 a is connected to the set of electrodes 14. The third power source 14 a is configured to be able to supply power to the third resistance heater 3. When viewed along a direction parallel to the top surface 5a1, the width of the third resistance heater 3 is smaller than the width of the top surface 5a1. The width of the third resistance heater 3 is measured so as not to include the electrode 14.

  Note that each of the crucible 5, the heat insulating material, the first resistance heater 1, the second resistance heater 10 and the third resistance heater 3 is made of, for example, carbon, and preferably made of graphite. Carbon (graphite) may contain impurities mixed in during production. Each of the electrodes 7, 8, and 14 may be made of, for example, carbon (preferably graphite), or may be made of a metal such as copper.

Next, a method for manufacturing a silicon carbide single crystal according to an embodiment of the present invention will be described.
First, the process (S10: FIG. 8) which prepares the manufacturing apparatus of a silicon carbide single crystal is implemented. For example, the above-described silicon carbide single crystal manufacturing apparatus 100 is prepared. Accordingly, the chamber 6, the top surface 5a1, the bottom surface 5b2 opposite to the top surface 5a1, and the cylindrical side surface 5b1 positioned between the top surface 5a1 and the bottom surface 5b2 are provided. And a second resistance heater 10 provided inside the chamber 6 and configured to surround the side surface 5b1 are prepared (see FIG. 1).

  Next, a step of preparing a silicon carbide raw material and a seed crystal (S20: FIG. 8) is performed. Specifically, as shown in FIG. 9, seed crystal 11 and silicon carbide source material 12 are arranged inside crucible 5. Silicon carbide raw material 12 is provided in housing portion 5 b of crucible 5. Silicon carbide raw material 12 is, for example, a powder of polycrystalline silicon carbide. The seed crystal 11 is fixed to the seed crystal holding surface 5a2 of the pedestal 5a using, for example, an adhesive. The seed crystal 11 is, for example, a polytype 4H hexagonal silicon carbide substrate. The seed crystal 11 has a back surface 11a fixed to the seed crystal holding surface 5a2 of the base 5a, and a surface 11b opposite to the back surface 11a. The diameter of the surface 11b of the seed crystal 11 is, for example, 100 mm or more, preferably 150 mm or more. The surface 11b of the seed crystal 11 is a surface that is off, for example, about 8 ° or less from the {0001} plane. Seed crystal 11 is arranged such that surface 11 b of seed crystal 11 faces surface 12 a of silicon carbide raw material 12. As described above, the silicon carbide raw material 12 provided inside the crucible 5 and the seed crystal 11 provided facing the silicon carbide raw material 12 inside the crucible 5 are prepared.

  Next, a step of growing a silicon carbide single crystal (S30: FIG. 8) is performed. Specifically, the crucible 5 is heated using the first resistance heater 1, the second resistance heater 10, and the third resistance heater 3. As shown in FIG. 11, crucible 5 that was at temperature A2 at time T0 is heated to temperature A1 at time T1. The temperature A2 is, for example, room temperature. The temperature A1 is, for example, a temperature of 2000 ° C. or higher and 2400 ° C. or lower. Both silicon carbide raw material 12 and seed crystal 11 are heated so that the temperature decreases from bottom surface 5b2 toward top surface 5a1. From time T1 to time T6, the crucible 5 is maintained at the temperature A1. As shown in FIG. 12, the inside of the chamber 6 is maintained at the pressure P1 from time T0 to time T2. The pressure P1 is, for example, atmospheric pressure. The atmospheric gas in the chamber 6 is an inert gas such as argon gas, helium gas, or nitrogen gas.

  At time T2, the pressure in the chamber 6 is reduced from the pressure P1 to the pressure P2. The pressure P2 is, for example, not less than 0.5 kPa and not more than 2 kPa. From time T3 to time T4, the pressure in the chamber 6 is maintained at the pressure P2. Between time T2 and time T3, silicon carbide raw material 12 begins to sublime. The sublimated silicon carbide is recrystallized on the surface 11 b of the seed crystal 11. From time T3 to time T4, the inside of the chamber 6 is maintained at the pressure P2. From time T3 to time T4, silicon carbide source material 12 continues to sublime, and silicon carbide single crystal 20 (see FIG. 10) grows on surface 11b of seed crystal 11. That is, the silicon carbide single crystal 20 grows on the surface 11 b of the seed crystal 11 by sublimating the silicon carbide raw material 12 by the first resistance heater 1, the second resistance heater 10, and the third resistance heater 3. In the step of growing the silicon carbide single crystal, the difference between the maximum temperature and the minimum temperature of the second resistance heater 10 is maintained at 100 ° C. or less. Preferably, the difference between the maximum temperature and the minimum temperature of the second resistance heater 10 is maintained at 100 ° C. or less during the time T2 and the time T5, and more preferably during the time T3 and the time T4. The difference between the maximum temperature and the minimum temperature is maintained below 100 ° C. Preferably, the difference between the maximum temperature and the minimum temperature of the second resistance heater 10 is maintained at 95 ° C. or less, more preferably 90 ° C. or less, further preferably 85 ° C. or less, and further preferably 80 ° C. Maintain below ℃. Preferably, in the step of growing the silicon carbide single crystal, the average temperature of the second resistance heater 10 is 2000 ° C. or more and 2400 ° C. or less, and the difference between the maximum temperature and the minimum temperature of the second resistance heater 10 is 100 ° C. or less. The pressure in the chamber is maintained at 0.5 kPa or more and 2 kPa or less. In the step of growing the silicon carbide single crystal, the average temperature of the second resistance heater 10 may be a certain temperature between 2000 ° C. and 2400 ° C., and the temperature of the second resistance heater 10 may vary. .

  In the step of growing the silicon carbide single crystal, the silicon carbide raw material 12 is maintained at a temperature at which silicon carbide sublimes, and the seed crystal 11 is maintained at a temperature at which silicon carbide is recrystallized. Specifically, the temperature of each of silicon carbide raw material 12 and seed crystal 11 is controlled as follows, for example. The temperature of the bottom surface 5b2 of the crucible 5 is measured using the lower radiation thermometer 9a. As shown in FIG. 13, the temperature of the bottom surface 5b2 measured by the lower radiation thermometer 9a is sent to the control unit. In the control unit, the temperature of the bottom surface 5b2 is compared with a desired temperature. When the temperature of the bottom surface 5b2 is higher than the desired temperature, for example, the first power supply 8a (see FIG. 6) is instructed to reduce the power supplied to the first resistance heater 1. On the other hand, when the temperature of the bottom surface 5b2 is lower than the desired temperature, for example, the first power supply 8a (see FIG. 6) is instructed to increase the power supplied to the first resistance heater 1. That is, the 1st power supply 8a supplies electric power with respect to the 1st resistance heater 1 based on the instruction | command from a control part. As described above, the power supplied to the first resistance heater 1 is determined based on the temperature of the bottom surface 5b2 measured by the lower radiation thermometer 9a, whereby the temperature of the bottom surface 5b2 is controlled to a desired temperature. . Alternatively, the electric power supplied to the first resistance heater 1 is determined based on the temperature of the first resistance heater 1 measured by the lower radiation thermometer 9a, thereby controlling the temperature of the bottom surface 5b2 to a desired temperature. May be. Furthermore, the temperature of the bottom surface 5b2 may be controlled to a desired temperature by determining the power supplied to the first resistance heater 1 based on the temperature of both the first resistance heater 1 and the bottom surface 5b2.

  Similarly, the electric power supplied to the second resistance heater 10 is determined based on the temperature of the side surface 5b1 measured by the side radiation thermometer 9b, whereby the temperature of the side surface 5b1 is controlled to a desired temperature. Alternatively, the power supplied to the second resistance heater 10 is determined based on the temperature of the second resistance heater 10 measured by the side radiation thermometer 9b, so that the temperature of the side surface 5b1 becomes a desired temperature. It may be controlled. Furthermore, the temperature of the side surface 5b1 may be controlled to a desired temperature by determining the power supplied to the second resistance heater 10 based on the temperature of both the second resistance heater 10 and the side surface 5b1.

  Similarly, the power supplied to the third resistance heater 3 is determined based on the temperature of the top surface 5a1 measured by the upper radiation thermometer 9c, whereby the temperature of the top surface 5a1 is controlled to a desired temperature. . Alternatively, the power supplied to the third resistance heater 3 is determined based on the temperature of the third resistance heater 3 measured by the upper radiation thermometer 9c, so that the temperature of the top surface 5a1 becomes a desired temperature. It may be controlled. Furthermore, the temperature of the top surface 5a1 may be controlled to a desired temperature by determining the power supplied to the third resistance heater 3 based on the temperature of both the third resistance heater 3 and the top surface 5a1. .

  Next, from time T4 to time T5, the pressure in the chamber 6 increases from the pressure P2 to the pressure P1 (see FIG. 12). As the pressure in the chamber 6 increases, sublimation of the silicon carbide raw material 12 is suppressed. Thereby, the process of growing a silicon carbide single crystal is substantially completed. At time T6, the heating of the crucible 5 is stopped and the crucible 5 is cooled. After the temperature of crucible 5 reaches around room temperature, silicon carbide single crystal 20 is taken out from crucible 5.

  Next, functions and effects of the silicon carbide single crystal manufacturing apparatus and manufacturing method according to the present embodiment will be described.

  Silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment includes a crucible 5 and a resistance heater 10. The crucible 5 has a top surface 5a1, a bottom surface 5b2 opposite to the top surface 5a1, and a cylindrical side surface 5b1 located between the top surface 5a1 and the bottom surface 5b2. The resistance heater 10 is configured to surround the side surface 5b1. The resistance heater 10 is provided continuously with the first portion 1x extending in the direction from the top surface 5a1 toward the bottom surface 5b2, the first portion 1x on the bottom surface 5b2 side, and along the circumferential direction of the side surface 5b1. A second portion 2x extending, a third portion 3x provided continuously with the second portion 2x and extending in a direction from the bottom surface 5b2 toward the top surface 5a1, and a third portion on the top surface 5a1 side And a fourth portion 4x provided continuously with 3x and extending along the circumferential direction of the side surface 5b1. The resistance heater 10 is configured so that the difference between the maximum temperature and the minimum temperature of the resistance heater 10 is 100 ° C. or less at a certain temperature between the average temperature of the resistance heater 10 and 2000 ° C. or more and 2400 ° C. or less. Thereby, the crystal quality of silicon carbide single crystal 20 can be improved.

  In addition, according to silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment, first portion 1x includes first surface 1x1 that faces third portion 3x, and second surface 1x2 that is opposite to first surface 1x1. Have The third portion 3x has a third surface 3x1 that faces the first surface 1x1, and a fourth surface 3x2 opposite to the third surface 3x1. The second portion 2x has a fifth surface 2x1 located between the first surface 1x1 and the third surface 3x1, and a sixth surface 2x2 opposite to the fifth surface 2x1. The distance between the second surface 1x2 and the fourth surface 3x2 in the circumferential direction is a, the distance between the first surface 1x1 and the third surface 3x1 in the circumferential direction is b, and the fifth in the direction from the top surface 5a1 to the bottom surface 5b2. When the shortest distance between the surface 2x1 and the sixth surface 2x2 is c and the curvature radius of the fifth surface 2x1 when viewed along the direction perpendicular to the side surface 5b1 is r, a ≧ 3b C ≧ b and r ≧ b / 2. Thereby, it can suppress that the temperature of the resistance heater 10 rises locally.

Furthermore, according to silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment, resistance heater 10 is made of carbon, and the density of carbon is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. is there.

Furthermore, according to silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment, resistance heater 10 is made of carbon, and the resistivity of carbon is 1200 μΩ · cm or more.

Silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment includes a crucible 5 and a resistance heater 10. The crucible 5 has a top surface 5a1, a bottom surface 5b2 opposite to the top surface 5a1, and a cylindrical side surface 5b1 located between the top surface 5a1 and the bottom surface 5b2. The resistance heater 10 is configured to surround the side surface 5b1. The resistance heater 10 is provided continuously with the first portion 1x extending in the direction from the top surface 5a1 toward the bottom surface 5b2, the first portion 1x on the bottom surface 5b2 side, and along the circumferential direction of the side surface 5b1. A second portion 2x extending, a third portion 3x provided continuously with the second portion 2x and extending in a direction from the bottom surface 5b2 toward the top surface 5a1, and a third portion on the top surface 5a1 side And a fourth portion 4x provided continuously with 3x and extending along the circumferential direction of the side surface 5b1. The resistance heater 10 is configured so that the difference between the maximum temperature and the minimum temperature of the resistance heater 10 is 100 ° C. or less at a certain temperature between the average temperature of the resistance heater 10 and 2000 ° C. or more and 2400 ° C. or less. The first portion 1x has a first surface 1x1 that faces the third portion 3x, and a second surface 1x2 opposite to the first surface 1x1. The third portion 3x has a third surface 3x1 that faces the first surface 1x1, and a fourth surface 3x2 opposite to the third surface 3x1. The second portion 2x has a fifth surface 2x1 located between the first surface 1x1 and the third surface 3x1, and a sixth surface 2x2 opposite to the fifth surface 2x1. The distance between the second surface 1x2 and the fourth surface 3x2 in the circumferential direction is a, the distance between the first surface 1x1 and the third surface 3x1 in the circumferential direction is b, and the fifth in the direction from the top surface 5a1 to the bottom surface 5b2. When the shortest distance between the surface 2x1 and the sixth surface 2x2 is c and the curvature radius of the fifth surface 2x1 when viewed along the direction perpendicular to the side surface 5b1 is r, a ≧ 3b C ≧ b and r ≧ b / 2. The resistance heater 10 is made of carbon, the density of carbon is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less, and the resistivity of carbon is 1200 μΩ · cm or more. Thereby, the crystal quality of silicon carbide single crystal 20 can be improved.

  According to the method for manufacturing a silicon carbide single crystal according to the present embodiment, top surface 5a1, bottom surface 5b2 opposite to top surface 5a1, and cylindrical side surface 5b1 located between top surface 5a1 and bottom surface 5b2 are provided. , A resistance heater 10 configured to surround the side surface 5b1, a raw material 12 provided inside the crucible 5, and a seed crystal 11 provided facing the raw material 12 inside the crucible 5. And are prepared. By sublimating raw material 12 with resistance heater 10, silicon carbide single crystal 20 grows on seed crystal 11. In the step of growing the silicon carbide single crystal 20, the difference between the maximum temperature and the minimum temperature of the resistance heater 10 is maintained at 100 ° C. or less. Thereby, the crystal quality of silicon carbide single crystal 20 can be improved.

  According to the method for manufacturing a silicon carbide single crystal according to the present embodiment, the average temperature of resistance heater 10 is maintained at 2000 ° C. or higher and 2400 ° C. or lower in the step of growing silicon carbide single crystal 20.

  Furthermore, according to the method for manufacturing a silicon carbide single crystal according to the present embodiment, the method further includes the step of preparing chamber 6 that accommodates crucible 5. In the process of growing silicon carbide single crystal 20, the pressure in chamber 6 is maintained at 0.5 kPa or more and 2 kPa or less.

  Furthermore, according to the method for manufacturing a silicon carbide single crystal according to the present embodiment, chamber 6, top surface 5 a 1 provided inside chamber 6, bottom surface 5 b 2 opposite to top surface 5 a 1, and top surface 5 a 1 And a crucible 5 having a cylindrical side surface 5b1 located between the bottom surface 5b2, a resistance heater 10 provided inside the chamber 6 and configured to surround the side surface 5b1, and provided inside the crucible 5 A prepared raw material 12 and a seed crystal 11 provided to face the raw material 12 inside the crucible 5 are prepared. The silicon carbide single crystal 20 grows on the seed crystal 11 by sublimating the raw material by the resistance heater 10. In the step of growing the silicon carbide single crystal 20, the average temperature of the resistance heater 10 is 2000 ° C. or more and 2400 ° C. or less, the difference between the maximum temperature and the minimum temperature of the resistance heater 10 is maintained at 100 ° C. or less, and in the chamber Is maintained at 0.5 kPa or more and 2 kPa or less. Thereby, the crystal quality of silicon carbide single crystal 20 can be improved.

  First, a resistance heater 10 according to Samples 1 to 6 was prepared. The resistance heater 10 according to the example is Sample 1 to Sample 5, and the resistance heater 10 according to the comparative example is Sample 6. The resistance heater 10 according to samples 1 to 6 includes a first portion 1x, a second portion 2x, a third portion 3x, and a fourth portion 4x (see FIGS. 3 and 4). The distance a between the second surface 1x2 of the first portion 1x in the circumferential direction and the fourth surface 3x2 of the third portion 3x, and the first surface 1x1 of the first portion 1x and the third surface 3x1 of the third portion 3x in the circumferential direction. And the shortest distance c between the fifth surface 6x2 and the sixth surface 2x2 of the second portion 2x in the direction from the top surface 5a1 to the bottom surface 5b2, and along the direction perpendicular to the side surface 5b1. The curvature radius r of the fifth surface 2x1 of the second portion 2x in this case was designed as shown in Table 1. Specifically, the distance a of the resistance heater 10 according to Sample 1 was 50 mm, the distance b was 15 mm, the shortest distance c was 20 mm, and the curvature radius r was 7.5 mm. The distance a of the resistance heater 10 according to Sample 2 was 60 mm, the distance b was 15 mm, the shortest distance c was 20 mm, and the radius of curvature r was 7.5 mm. The distance a of the resistance heater 10 according to Sample 3 was 50 mm, the distance b was 10 mm, the shortest distance c was 15 mm, and the radius of curvature r was 5 mm. The distance a of the resistance heater 10 according to Sample 4 was 50 mm, the distance b was 15 mm, the shortest distance c was 25 mm, and the curvature radius r was 7.5 mm. The distance a of the resistance heater 10 according to the sample 5 was 50 mm, the distance b was 15 mm, the shortest distance c was 20 mm, and the radius of curvature r was 10 mm. The distance a of the resistance heater 10 according to the sample 6 was 40 mm, the distance b was 15 mm, the shortest distance c was 10 mm, and the radius of curvature r was 4 mm.

Next, the maximum temperature and the minimum temperature of the resistance heater 10 according to Sample 1 to Sample 6 were calculated by thermal analysis simulation, and the difference (temperature difference) between the maximum temperature and the minimum temperature of the resistance heater 10 was obtained. As a thermal analysis program used for thermal analysis simulation, STAR-CCM + (registered trademark) manufactured by IDAJ Co., Ltd. was used. The size of the mesh region M (see FIG. 5) of the shape model of the resistance heater 10 was set to 0.5 mm. The density of carbon constituting the resistance heater 10 was 1.75 g / cm ² . The average temperature of the resistance heater 10 was 2200 ° C. The thickness of the resistance heater 10 in the direction perpendicular to the side surface 5b1 was 15 mm.

Next, silicon carbide single crystal 20 was manufactured using resistance heater 10 according to samples 1 to 6, and the crystal quality of silicon carbide single crystal 20 was evaluated. The crystal quality of the silicon carbide single crystal was evaluated by measuring the dislocation density. In Table 1, the symbol A indicates that the dislocation density is less than 5000 cm ⁻² , and the symbol B indicates that the dislocation density is 5000 cm ⁻² or more.

  Table 1 shows the shape parameters (distance a, distance b, shortest distance c, and radius of curvature r) of the resistance heater 10, the difference (temperature difference) between the maximum temperature and the minimum temperature in the resistance heater 10, and the silicon carbide single crystal. It shows the relationship with the crystal quality.

  As shown in Table 1, the temperature difference of the resistance heater 10 according to Samples 1 to 5 was 100 ° C. or less, and the temperature difference of the resistance heater 10 according to Sample 6 was 120 ° C. Moreover, the crystal quality of the silicon carbide single crystal manufactured using the resistance heater 10 which concerns on the samples 1-5 was favorable. The crystal quality of the silicon carbide single crystal manufactured using the resistance heater 10 according to the sample 6 is inferior to the crystal quality of the silicon carbide single crystal manufactured by the silicon carbide single crystal manufacturing apparatus 100 according to the samples 1 to 5. It was. From the above results, it was confirmed that the crystal quality of the silicon carbide single crystal can be improved by growing the silicon carbide single crystal with the temperature difference of the resistance heater 10 being 100 ° C. or less.

  The embodiments and examples disclosed herein are illustrative in all respects and should not be construed as being restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 1st resistance heater 1a Upper surface 1b Lower surface 1x 1st part 1x1 1st surface 1x2 2nd surface 1y 5th part 1y2 7th surface 1y1 8th surface 2x 2nd part 2x2 6th surface 2x1 5th surface 2y 6th part 3 3rd resistance heater 3x1 3rd surface 3x2 4th surface 3x 3rd part 3y 7th part 4x2 9th surface 4x 4th part 4x1 10th surface 4y 8th part 5 Crucible 5a1 Top surface 5a Base 5a2 Seed crystal holding surface 5b2 Bottom surface 5b1 Side surface 5b Housing 6 Chamber 6a, 6b, 6c Window 7, 8, 14 Electrode 7a Second power source 8a First power source 9a Lower radiation thermometer (radiation thermometer)
9b Side radiation thermometer 9c Upper radiation thermometer 10 Second resistance heater (resistance heater)
10a inner peripheral surface 10b outer peripheral surface 10x, 10y heater unit 11 seed crystal 11a back surface 11b, 12a surface 12 raw material (silicon carbide raw material)
14a Third power source 20 Silicon carbide single crystal 100 Manufacturing apparatus A1, A2 Temperature M Mesh region P1, P2 Pressure T0, T1, T2, T3, T4, T5, T6 Time W1, W2 Width a, b Distance c Shortest distance r Curvature radius

Claims (8)

A crucible having a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface;
A first resistance heater provided facing the bottom surface;
A second resistance heater configured to surround the side surface;
The second resistance heater includes a first portion extending along a direction from the top surface toward the bottom surface, the second resistance heater being provided continuously with the first portion on the bottom surface side, and along a circumferential direction of the side surface. A second portion that extends continuously from the bottom surface along the direction from the bottom surface toward the top surface, and the third portion on the top surface side. And a fourth portion that is provided continuously and extends along the circumferential direction of the side surface,
The second resistance heater is arranged so that the difference between the maximum temperature and the minimum temperature of the second resistance heater is 100 ° C. or less at a certain temperature between 2000 ° C. and 2400 ° C. in average temperature of the second resistance heater. Configured,
The first portion has a first surface facing the third portion, and a second surface opposite to the first surface,
The third portion has a third surface facing the first surface, and a fourth surface opposite to the third surface,
The second portion has a fifth surface located between the first surface and the third surface, and a sixth surface opposite to the fifth surface,
The distance between the second surface and the fourth surface in the circumferential direction is a,
The distance between the first surface and the third surface in the circumferential direction is b,
The shortest distance between the fifth surface and the sixth surface in the direction from the top surface to the bottom surface is c, and the radius of curvature of the fifth surface when viewed along the direction perpendicular to the side surface Where r is
a a ≧ 3b, a c ≧ b, and Ri r ≧ b / 2 der,
When viewed along the direction from the top surface to the bottom surface, the first resistance heater is a silicon carbide single crystal manufacturing apparatus having a shape in which two curves moving away from the center merge at the center as they turn . The second resistance heater is made of carbon,
2. The apparatus for producing a silicon carbide single crystal according to claim 1, wherein the density of the carbon is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The second resistance heater is made of carbon,
The silicon carbide single crystal manufacturing apparatus according to claim 1, wherein the resistivity of the carbon is 1200 μΩ · cm or more. A crucible having a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface;
A first resistance heater provided facing the bottom surface;
A second resistance heater configured to surround the side surface;
The second resistance heater includes a first portion extending along a direction from the top surface toward the bottom surface, the second resistance heater being provided continuously with the first portion on the bottom surface side, and along a circumferential direction of the side surface. A second portion that extends continuously from the bottom surface along the direction from the bottom surface toward the top surface, and the third portion on the top surface side. And a fourth portion that is provided continuously and extends along the circumferential direction of the side surface,
The second resistance heater is arranged so that the difference between the maximum temperature and the minimum temperature of the second resistance heater is 100 ° C. or less at a certain temperature between 2000 ° C. and 2400 ° C. in average temperature of the second resistance heater. Configured,
The first portion has a first surface facing the third portion, and a second surface opposite to the first surface,
The third portion has a third surface facing the first surface, and a fourth surface opposite to the third surface,
The second portion has a fifth surface located between the first surface and the third surface, and a sixth surface opposite to the fifth surface,
The distance between the second surface and the fourth surface in the circumferential direction is a,
The distance between the first surface and the third surface in the circumferential direction is b,
The shortest distance between the fifth surface and the sixth surface in the direction from the top surface to the bottom surface is c, and the radius of curvature of the fifth surface when viewed along the direction perpendicular to the side surface Where r is
a ≧ 3b, c ≧ b, and r ≧ b / 2,
The second resistance heater is made of carbon,
Density of the carbon, 1.7 g / cm ³ or more 1.9 g / cm ³ or less and the resistivity of the carbon state, and are 1200 [mu] [Omega] · cm or more,
When viewed along the direction from the top surface to the bottom surface, the first resistance heater is a silicon carbide single crystal manufacturing apparatus having a shape in which two curves moving away from the center merge at the center as they turn . A crucible having a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface;
A first resistance heater provided facing the bottom surface;
A second resistance heater configured to surround the side surface;
Raw materials provided inside the crucible;
Preparing a seed crystal provided facing the raw material inside the crucible;
A step of growing a silicon carbide single crystal on the seed crystal by sublimating the raw material by the second resistance heater,
The second resistance heater includes a first portion extending along a direction from the top surface toward the bottom surface, the second resistance heater being provided continuously with the first portion on the bottom surface side, and along a circumferential direction of the side surface. A second portion that extends continuously from the bottom surface along the direction from the bottom surface toward the top surface, and the third portion on the top surface side. And a fourth portion that is provided continuously and extends along the circumferential direction of the side surface,
The first portion has a first surface facing the third portion, and a second surface opposite to the first surface,
The third portion has a third surface facing the first surface, and a fourth surface opposite to the third surface,
The second portion has a fifth surface located between the first surface and the third surface, and a sixth surface opposite to the fifth surface,
The distance between the second surface and the fourth surface in the circumferential direction is a,
The distance between the first surface and the third surface in the circumferential direction is b,
The shortest distance between the fifth surface and the sixth surface in the direction from the top surface to the bottom surface is c, and the radius of curvature of the fifth surface when viewed along the direction perpendicular to the side surface Where r is
a ≧ 3b, c ≧ b, and r ≧ b / 2,
When viewed along the direction from the top surface to the bottom surface, the first resistance heater has a shape in which two curves moving away from the center as they turn meet at the center.
The method for producing a silicon carbide single crystal, wherein, in the step of growing the silicon carbide single crystal, a difference between a maximum temperature and a minimum temperature of the second resistance heater is maintained at 100 ° C. or less. 6. The method for producing a silicon carbide single crystal according to claim 5, wherein in the step of growing the silicon carbide single crystal, an average temperature of the second resistance heater is maintained at 2000 ° C. or more and 2400 ° C. or less. Further comprising the step of preparing a chamber containing the crucible,
The method for producing a silicon carbide single crystal according to claim 5 or 6, wherein, in the step of growing the silicon carbide single crystal, the pressure in the chamber is maintained at 0.5 kPa or more and 2 kPa or less. A chamber;
A crucible provided inside the chamber and having a top surface, a bottom surface opposite to the top surface, and a cylindrical side surface located between the top surface and the bottom surface;
A first resistance heater provided facing the bottom surface;
A second resistance heater provided inside the chamber and configured to surround the side surface;
Raw materials provided inside the crucible;
Preparing a seed crystal provided facing the raw material inside the crucible;
A step of growing a silicon carbide single crystal on the seed crystal by sublimating the raw material by the second resistance heater,
The second resistance heater includes a first portion extending along a direction from the top surface toward the bottom surface, the second resistance heater being provided continuously with the first portion on the bottom surface side, and along a circumferential direction of the side surface. A second portion that extends continuously from the bottom surface along the direction from the bottom surface toward the top surface, and the third portion on the top surface side. And a fourth portion that is provided continuously and extends along the circumferential direction of the side surface,
The first portion has a first surface facing the third portion, and a second surface opposite to the first surface,
The third portion has a third surface facing the first surface, and a fourth surface opposite to the third surface,
The second portion has a fifth surface located between the first surface and the third surface, and a sixth surface opposite to the fifth surface,
The distance between the second surface and the fourth surface in the circumferential direction is a,
The distance between the first surface and the third surface in the circumferential direction is b,
The shortest distance between the fifth surface and the sixth surface in the direction from the top surface to the bottom surface is c, and the radius of curvature of the fifth surface when viewed along the direction perpendicular to the side surface Where r is
a ≧ 3b, c ≧ b, and r ≧ b / 2,
When viewed along the direction from the top surface to the bottom surface, the first resistance heater has a shape in which two curves moving away from the center as they turn meet at the center.
In the step of growing the silicon carbide single crystal,
The average temperature of the second resistance heater is 2000 ° C. or more and 2400 ° C. or less, the difference between the maximum temperature and the minimum temperature of the second resistance heater is maintained at 100 ° C. or less, and the pressure in the chamber is 0.5 kPa. The manufacturing method of the silicon carbide single crystal maintained above 2 kPa or less.

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