JP2019073441A - Device and method for producing silicon carbide single crystal - Google Patents

Abstract

To provide a device and method for producing a silicon carbide single crystal that can suppress deterioration of a resistance heater.SOLUTION: A silicon carbide single crystal production device 100 includes a crucible 5, a resistance heater 2, and a power source 7a. 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 2 is installed outside the crucible 5 and formed of carbon. The power source 7a is configured to allow supply of electric power to the resistance heater 2. The power source 7a and the resistance heater 2 are configured so that a value obtained by dividing a value of current flowing through the resistance heater 2 by the cross sectional area of the resistance heater 2 perpendicular to a current flow direction is 5 A/mmor less when temperature of the resistance heater 2 falls within the range of 2,000°C or more and 2,400°C or less by supplying electric power to the resistance heater 2 by the power source 7a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for producing a silicon carbide single crystal and a method for producing a silicon carbide single crystal.

  In recent years, in order to make it possible to increase the breakdown voltage and lower the loss of a semiconductor device, adoption of silicon carbide as a material of which the semiconductor device is constructed has been advanced.

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

JP 2012-510951 gazette

  An object of one aspect of the present invention is to provide an apparatus for producing a silicon carbide single crystal capable of suppressing deterioration of a resistance heater and a method for producing a silicon carbide single crystal.

An apparatus for manufacturing a silicon carbide single crystal according to an aspect of the present invention includes a crucible, a resistance heater, and a power supply. 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 provided outside the crucible and is made of carbon. The power supply is configured to be able to supply power to the resistance heater. When the temperature of the resistive heater reaches a certain temperature between 2000 ° C. and 2400 ° C. by supplying power to the resistive heater by the power supply, the value of the current flowing through the resistive heater is perpendicular to the direction of the current flow The resistance heater is configured such that the value divided by the cross-sectional area of the resistance heater is 5 A / mm ² or less.

An apparatus for manufacturing a silicon carbide single crystal according to an aspect of the present invention includes a crucible, a first resistance heater, a second resistance heater, a third resistance heater, a first power supply, a second power supply, and a third power supply. And 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 first resistance heater is provided facing the bottom and is made of carbon. The second resistive heater is configured to surround the side surface and is made of carbon. The third resistance heater is provided facing the top surface and is made of carbon. The first power supply is configured to be able to supply power to the first resistance heater. The second power supply is configured to be able to supply power to the second resistance heater. The third power supply is configured to be able to supply power to the third resistance heater. When the first power supply supplies power to the first resistance heater and the temperature of the first resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the first current flowing to the first resistance heater is The first resistance heater is configured such that the value divided by the first cross-sectional area of the first resistance heater perpendicular to the direction in which the first current flows is 5 A / mm ² or less. When the second power supply supplies power to the second resistance heater and the temperature of the second resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the second current flowing to the second resistance heater is The second resistance heater is configured such that the value divided by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is 5 A / mm ² or less. When the third power supply supplies power to the third resistance heater and the temperature of the third resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the third current flowing to the third resistance heater is The third resistance heater is configured such that the value divided by the third cross-sectional area of the third resistance heater perpendicular to the direction in which the third current flows is 5 A / mm ² or less. Each of the first cross sectional area, the second cross sectional area, and the third cross sectional area is 100 mm ² or more and 500 mm ² or less. The density of carbon constituting each of the first resistance heater, the second resistance heater, and the third resistance heater is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater, the second resistance heater, and the third resistance heater is 1200 mΩ · cm or more.

The method for producing a silicon carbide single crystal according to an aspect 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, and a resistance heater provided on the outside of the crucible and made of carbon; A raw material provided inside the crucible and a seed crystal provided facing the raw material inside the crucible are prepared. By subliming the raw material with the resistance heater, a silicon carbide single crystal grows on the seed crystal. In the step of growing the silicon carbide single crystal, the value obtained by dividing the value of the current flowing through the resistance heater by the cross-sectional area of the resistance heater perpendicular to the current flow direction is maintained at 5 A / mm ² or less.

The method for producing a silicon carbide single crystal according to an aspect of the present invention includes the following steps. A chamber having 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 and consisting of carbon, a second resistance heater consisting of carbon and configured to surround the side in the interior of the chamber, and a top facing inside the chamber And a third resistance heater made of carbon, a raw material provided inside the crucible, and a seed crystal provided so as to face the raw material inside the crucible. By sublimating the raw material, a silicon carbide single crystal grows on the seed crystal. In the step of growing the silicon carbide single crystal, the temperature of the first resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the value of the first current flowing through the first resistance heater is perpendicular to the direction of the first current flow The value divided by the first cross-sectional area of the first resistance heater is maintained at 5 A / mm ² or less, the temperature of the second resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the second current flows to the second resistance heater Divided by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is maintained at 5 A / mm ² or less. The temperature of the third resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the value of the third current flowing through the third resistance heater is the third cross-sectional area of the third resistance heater perpendicular to the direction in which the third current flows The value divided by is maintained at 5 A / mm ² or less. The pressure of the chamber is maintained at 0.5 kPa or more and 2 kPa or less.

  According to the above, the manufacturing apparatus of the silicon carbide single crystal which can suppress degradation of a resistance heater, and the manufacturing method of a silicon carbide single crystal 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 perspective view showing the composition of the 2nd resistance heater. It is a plane schematic diagram which shows the structure of a 2nd resistance heater and an electrode. It is the arrow transverse cross-section schematic diagram along the IV-IV line of FIG. 1, and is a cross-sectional schematic diagram which shows the structure of a 1st resistance heater and an electrode. It is the arrow transverse cross-section schematic diagram along the VV 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 perspective view showing a section of a resistance heater perpendicular to the direction where current flows. It is a flowchart which shows the manufacturing method of the silicon carbide single crystal concerning embodiment of this invention. It is a longitudinal cross-section schematic diagram which shows the 1st process of the manufacturing method of the silicon carbide single crystal concerning embodiment of this invention. It is a longitudinal cross-section 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 coffin, 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 carrying out feedback control of the electric power supplied to a resistance heater. It is a figure which shows the relationship of the resistance increase rate and electric current density of 100 hours after electricity supply.

Description of the embodiment of the present invention
Hereinafter, embodiments of the present invention will be described based on the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. In the crystallographic description in the present 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 {}. Also, as for the negative index, in crystallographic terms, "-" (bar) is to be added above the numbers, but in the present specification, the numbers are attached with a negative sign.

  When a silicon carbide single crystal is grown by sublimation, 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. In the step of growing the silicon carbide single crystal, the temperature of the resistance heater is, for example, about 2000 ° C. or more and about 2400 ° C. or less, and the pressure of the chamber in which the resistance heater is disposed is, for example, about 1 kPa. Under such a high temperature and low pressure environment, carbon constituting the resistance heater is easily sublimated, so that the resistance heater is deteriorated.

(1) An apparatus for manufacturing a silicon carbide single crystal according to an aspect of the present invention includes a crucible, a resistance heater, and a power supply. 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 provided outside the crucible and is made of carbon. The power supply is configured to be able to supply power to the resistance heater. When the temperature of the resistive heater reaches a certain temperature between 2000 ° C. and 2400 ° C. by supplying power to the resistive heater by the power supply, the value of the current flowing through the resistive heater is perpendicular to the direction of the current flow The power supply and the resistance heater are configured such that the value divided by the cross-sectional area of the resistance heater is 5 A / mm ² or less. Thereby, the deterioration of the resistance heater can be suppressed.

(2) In the apparatus for manufacturing a silicon carbide single crystal according to the above (1), preferably, the density of carbon constituting the resistance heater is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less.

  (3) In the apparatus for manufacturing a silicon carbide single crystal according to (1) or (2) above, preferably, the resistivity of carbon constituting the resistance heater is 1200 mΩ · cm or more.

(4) above (1), preferably in the manufacturing apparatus of a silicon carbide single crystal according to any one of the - (3), the cross-sectional area of the resistive heater is 100 mm ² or more 500 mm ² or less.

(5) The apparatus for manufacturing a silicon carbide single crystal according to one aspect of the present invention includes a crucible, a first resistance heater, a second resistance heater, a third resistance heater, a first power supply, and a second power supply. And a third power source. 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 first resistance heater is provided facing the bottom and is made of carbon. The second resistive heater is configured to surround the side surface and is made of carbon. The third resistance heater is provided facing the top surface and is made of carbon. The first power supply is configured to be able to supply power to the first resistance heater. The second power supply is configured to be able to supply power to the second resistance heater. The third power supply is configured to be able to supply power to the third resistance heater. When the first power supply supplies power to the first resistance heater and the temperature of the first resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the first current flowing to the first resistance heater is The first power supply and the first resistance heater are configured such that the value divided by the first cross-sectional area of the first resistance heater perpendicular to the direction in which the first current flows is 5 A / mm ² or less. When the second power supply supplies power to the second resistance heater and the temperature of the second resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the second current flowing to the second resistance heater is The second power supply and the second resistance heater are configured such that the value divided by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is 5 A / mm ² or less. When the third power supply supplies power to the third resistance heater and the temperature of the third resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the third current flowing to the third resistance heater is The third power supply and the third resistance heater are configured such that the value divided by the third cross-sectional area of the third resistance heater perpendicular to the direction in which the third current flows is 5 A / mm ² or less. Each of the first cross sectional area, the second cross sectional area, and the third cross sectional area is 100 mm ² or more and 500 mm ² or less. The density of carbon constituting each of the first resistance heater, the second resistance heater, and the third resistance heater is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater, the second resistance heater, and the third resistance heater is 1200 mΩ · cm or more. Thereby, deterioration of the first resistance heater, the second resistance heater, and the third resistance heater can be suppressed.

(6) The method for producing a silicon carbide single crystal according to one aspect 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, and a resistance heater provided on the outside of the crucible and made of carbon; A raw material provided inside the crucible and a seed crystal provided facing the raw material inside the crucible are prepared. By subliming the raw material with the resistance heater, a silicon carbide single crystal grows on the seed crystal. In the step of growing the silicon carbide single crystal, the value obtained by dividing the value of the current flowing through the resistance heater by the cross-sectional area of the resistance heater perpendicular to the current flow direction is maintained at 5 A / mm ² or less.
Thereby, the deterioration of the resistance heater can be suppressed.

  (7) In the method for producing a silicon carbide single crystal according to (6) above, preferably, in the step of growing the silicon carbide single crystal, the temperature of the resistance heater is maintained at 2000 ° C. or more and 2400 ° C. or less.

  (8) Preferably, the method for producing a silicon carbide single crystal according to (6) or (7) above further includes the step of preparing a chamber for containing a crucible. The pressure of the chamber in the step of growing the silicon carbide single crystal is maintained at 0.5 kPa or more and 2 kPa or less.

(9) The method for producing a silicon carbide single crystal according to one aspect of the present invention includes the following steps. A chamber having 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 and consisting of carbon, a second resistance heater consisting of carbon and configured to surround the side in the interior of the chamber, and a top facing inside the chamber And a third resistance heater made of carbon, a raw material provided inside the crucible, and a seed crystal provided so as to face the raw material inside the crucible. By sublimating the raw material, a silicon carbide single crystal grows on the seed crystal. In the step of growing the silicon carbide single crystal, the temperature of the first resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the value of the first current flowing through the first resistance heater is perpendicular to the direction of the first current flow The value divided by the first cross-sectional area of the first resistance heater is maintained at 5 A / mm ² or less, the temperature of the second resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the second current flows to the second resistance heater Divided by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is maintained at 5 A / mm ² or less. The temperature of the third resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the value of the third current flowing through the third resistance heater is the third cross-sectional area of the third resistance heater perpendicular to the direction in which the third current flows The value divided by is maintained at 5 A / mm ² or less. The pressure of the chamber is maintained at 0.5 kPa or more and 2 kPa or less. Thereby, deterioration of the first resistance heater, the second resistance heater, and the third resistance heater can be suppressed.
Details of the Embodiment of the Present Invention
The structure of the manufacturing apparatus 100 of the silicon carbide single crystal which concerns on embodiment of this invention is demonstrated.

  As shown in FIG. 1, the 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 a crucible 5 and a first resistance heater 1. The second resistance heater 2, the third resistance heater 3, the chamber 6, the lower radiation thermometer 9a, the side radiation thermometer 9b, and the upper radiation thermometer 9c are mainly included. 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 has a pedestal 5 a configured to be capable of holding the seed crystal 11, and a housing portion 5 b configured to be capable of housing the silicon carbide material 12. The pedestal 5 a has a seed crystal holding surface 5 a 2 in contact with the back surface 11 a of the seed crystal 11 and a top surface 5 a 1 opposite to the seed crystal holding surface 5 a 2. The pedestal 5a constitutes the top surface 5a1. The housing portion 5 b constitutes a bottom surface 5 b 2. The side surface 5b1 is configured by the pedestal 5a and the housing 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 producible by the sublimation method.

  Each of the first resistance heater 1, the second resistance heater 2 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 2 is configured to surround the side surface 5b1. The second resistance heater 2 is separated from the side surface 5b1. The second resistance heater has a first surface 2a located on the top surface 5a1 side, a second surface 2b located on the bottom surface 5b2 side, and a third surface facing the side surface 5b1 in the direction from the bottom surface 5b2 to the top surface 5a1. 2c and a fourth surface 2d opposite to the third surface 2c. Preferably, the second surface 2b of the second resistance heater 2 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 at a position facing the bottom surface 5b2 outside the chamber 6, and is configured to be able to measure the temperature of the bottom surface 5b2 through the window 6a. The lower radiation thermometer 9 a may be provided at a position facing the first resistance heater 1, and may be configured to be capable of measuring 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 9 b may be provided at a position facing the second resistance heater 2 so as to be able to measure the temperature of the second resistance heater 2. 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 9 c may be provided at a position facing the third resistance heater 3, and may be configured to be capable of measuring the temperature of the third resistance heater 3.

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

  As shown in FIGS. 1 and 2, the second resistance heater 2 is continuous with the first portion 1x extending along the direction from the top surface 5a1 to the bottom surface 5b2, and the first portion 1x on the bottom surface 5b2 side. A second portion 2x provided along the circumferential direction of the side surface 5b1 and a second portion 2x continuously extending from the bottom surface 5b2 to the top surface 5a1 It has a third portion 3x and a fourth portion 4x provided continuously with the third portion 3x on the top surface 5a1 side and extending along the circumferential direction of the side surface 5b1. The first portion 1x, the second portion 2x, the third portion 3x, and the fourth portion 4x constitute a heater unit 10x. The second resistance heater 2 is configured in a ring shape in which a plurality of heater units 10x are continuously provided.

  As shown in FIG. 3, when viewed in the direction from the top surface 5 a 1 to the bottom surface 5 b 2, the second resistance heater 2 is provided so as to surround the side surface 5 b 1 and has a ring shape. A pair of electrodes 7 is provided in contact with the fourth surface 2 d of the second resistance heater 2. When viewed in the direction perpendicular to the top surface 5a1, the pair of electrodes 7 and the top surface 5a1 may be provided on a straight line. The second power source 7 a is connected to the pair of electrodes 7. The second power supply 7 a is configured to be able to supply power to the second resistance heater 2. Preferably, the second resistance heater 2 constitutes a parallel circuit.

When the second power supply 7a supplies power to the second resistance heater 2 and the temperature of the second resistance heater 2 reaches a certain temperature between 2000 ° C. and 2400 ° C., the current flowing through the second resistance heater 2 ( The value (second current density) obtained by dividing the value of the second current by the cross-sectional area (second cross-sectional area) of the second resistance heater 2 perpendicular to the direction in which the second current flows is 1 A / mm ² or more The second power supply 7a and the second resistance heater 2 are configured to be 5 A / mm ² or less. Preferably, the second current density is 4A / mm ² or less, more preferably 3A / mm ² or less. Preferably, the second cross-sectional area is 100 mm ² or more and 500 mm ² or less. When the cross-sectional area of the second resistance heater 2 changes along the direction in which the second current flows, the minimum value of the cross-sectional area of the second resistance heater 2 is preferably 100 mm ² or more and 500 mm ² or less. When the cross-sectional area of the second resistance heater 2 changes along the direction in which the second current flows, the maximum value of the current density of the second resistance heater 2 is preferably 5 A / mm ² or less.

  As shown in FIG. 4, when viewed from the top surface 5a1 to the bottom surface 5b2, the first resistance heater 1 has a shape in which two curves moving away from the center merge at the center as it turns. Preferably, the first resistance heater 1 has a Fermat spiral shape. A pair of electrodes 8 is connected to both ends of the first resistance heater 1. The first power source 8 a is connected to the pair 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 (see FIG. 1) inside the weir 5 and preferably, it is larger than the width of the bottom surface 5b2 large. The width W 1 of the first resistance heater 1 is measured so as not to include the electrode 8.

When the first power supply 8 a supplies power to the first resistance heater 1 and the temperature of the first resistance heater 1 reaches a certain temperature between 2000 ° C. and 2400 ° C., the current flowing through the first resistance heater 1 ( The value (first current density) obtained by dividing the value of the first current by the cross-sectional area (first cross-sectional area) of the first resistance heater 1 perpendicular to the direction in which the first current flows is 1 A / mm ² or more The first power supply 8 a and the first resistance heater 1 are configured to be 5 A / mm ² or less. Preferably, the first current density is 4 A / mm ² or less, more preferably 3 A / mm ² or less. Preferably, the first cross-sectional area is 100 mm ² or more and 500 mm ² or less. When the cross-sectional area of the first resistance heater 1 changes along the direction in which the first current flows, the minimum value of the cross-sectional area of the first resistance heater 1 is preferably 100 mm ² or more and 500 mm ² or less. When the cross-sectional area of the first resistance heater 1 changes along the direction in which the first current flows, the maximum value of the current density of the first resistance heater 1 is preferably 5 A / mm ² or less.

  As shown in FIG. 5, when viewed from the top surface 5a1 to the bottom surface 5b2, the third resistance heater 3 has a shape in which two curves moving away from the center merge at the center as it turns. 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. The third power source 14 a is connected to the pair of electrodes 14. The third power supply 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.

When the third power supply 14 a supplies power to the third resistance heater 3 and the temperature of the third resistance heater 3 reaches a certain temperature between 2000 ° C. and 2400 ° C., the current flowing through the third resistance heater 3 ( The value (third current density) obtained by dividing the value of the third current by the cross-sectional area (third cross-sectional area) of the third resistance heater 3 perpendicular to the direction in which the third current flows is 1 A / mm ² or more The third power supply 14 a and the third resistance heater 3 are configured to be 5 A / mm ² or less. Preferably, the third current density is 4A / mm ² or less, more preferably 3A / mm ² or less. Preferably, the third cross-sectional area is 100 mm ² or more and 500 mm ² or less. When the cross-sectional area of the third resistance heater 3 changes along the direction in which the third current flows, the minimum value of the cross-sectional area of the third resistance heater 3 is preferably 100 mm ² or more and 500 mm ² or less. When the cross-sectional area of the third resistance heater 3 changes along the direction in which the third current flows, it is preferable that the maximum value of the current density of the third resistance heater 3 is 5 A / mm ² or less.

  As shown in FIG. 6, the shape of the cross section CS of the resistance heater 2 perpendicular to the direction of the current flowing in the resistance heater 2 may be rectangular. The shape of the cross section CS may be a polygon, an ellipse, a circle, or a chamfered corner of a rectangle.

Each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is made of carbon. The density of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is, for example, 1.6 g / cm ³ or more and 2.0 g / cm ³ or less, preferably 1.7 g / Cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is, for example, 1100 mΩ · cm or more and 1800 mΩ · cm or less, preferably 1200 mΩ · cm or more and 1700 mΩ · cm It is below.

  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 during production. Each of the electrodes 7, 8, 14 may be made of, for example, carbon (preferably graphite), or may be made of a metal such as copper.

Next, a method of manufacturing a silicon carbide single crystal according to the embodiment of the present invention will be described.
First, the step of preparing a silicon carbide single crystal manufacturing apparatus (S10: FIG. 7) is performed. For example, the manufacturing apparatus 100 of the silicon carbide single crystal mentioned above is prepared. Thus, the chamber 6, the crucible 5, the first resistance heater 1, the second resistance heater 2, and the third resistance heater 3 are prepared (see FIG. 1). The crucible 5 is provided inside the chamber 6 and 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 first resistance heater 1 is provided to face the bottom surface 5 b 2 inside the chamber 6 and is made of carbon. The second resistance heater 2 is configured to surround the side surface 5b1 inside the chamber 6, and is configured from carbon. The third resistance heater 3 is provided inside the chamber 6 so as to face the top surface 5a1, and is made of carbon. Each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is provided outside the crucible 5. The chamber 6 accommodates the crucible 5, the first resistance heater 1, the second resistance heater 2, and the third resistance heater 3.

  Next, a step of preparing a silicon carbide raw material and a seed crystal (S20: FIG. 7) is performed. Specifically, as shown in FIG. 8, seed crystal 11 and silicon carbide raw 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. Seed crystal 11 is fixed to seed crystal holding surface 5a2 of pedestal 5a using, for example, an adhesive. Seed crystal 11 is a substrate of hexagonal silicon carbide of polytype 4H, for example. The seed crystal 11 has a back surface 11a fixed to the seed crystal holding surface 5a2 of the pedestal 5a and a surface 11b opposite to the back surface 11a. The diameter of the surface 11 b of the seed crystal 11 is, for example, 100 mm or more, preferably 150 mm or more. The surface 11 b of the seed crystal 11 is, for example, a surface which is off by 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 material 12 provided inside the crucible 5 and the seed crystal 11 provided facing the silicon carbide material 12 inside the crucible 5 are prepared.

  Next, the step of growing a silicon carbide single crystal (S30: FIG. 7) is performed. Specifically, the crucible 5 is heated using the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3. As shown in FIG. 10, crucible 5 which was at temperature A2 at time T0 is heated to temperature A1 at time T1. The temperature A2 is, for example, room temperature. Temperature A1 is, for example, a temperature of 2000 ° C. or more and 2400 ° C. or less. Both silicon carbide raw material 12 and seed crystal 11 are heated such that the temperature decreases from bottom surface 5 b 2 to top surface 5 a 1. From time T1 to time T6, crucible 5 is maintained at temperature A1. As shown in FIG. 11, 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 atmosphere gas in the chamber 6 is, for example, an inert gas such as argon gas, helium gas or nitrogen gas.

  At time T2, the pressure in chamber 6 is reduced from pressure P1 to pressure P2. The pressure P2 is, for example, not less than 0.5 kPa and not more than 2 kPa. The pressure in the chamber 6 is maintained at the pressure P2 from time T3 to time T4. Between time T2 and time T3, silicon carbide source 12 begins to sublime. The sublimated silicon carbide is recrystallized on surface 11 b of seed crystal 11. The inside of the chamber 6 is maintained at the pressure P2 from time T3 to time T4. During time T3 to time T4, silicon carbide raw material 12 continues to sublime, and silicon carbide single crystal 20 (see FIG. 9) grows on surface 11b of seed crystal 11. That is, the silicon carbide raw material 12 is sublimated by the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3, whereby the silicon carbide single crystal 20 is grown on the surface 11 b of the seed crystal 11. Preferably, the pressure in chamber 6 in the step of growing the silicon carbide single crystal is maintained at 0.5 kPa or more and 2 kPa or less.

Preferably, in the step of growing the silicon carbide single crystal, the temperature of the second resistance heater 2 is 2000 ° C. or more and 2400 ° C. or less, and the value of the current (second current) flowing through the second resistance heater 2 is The value (second current density) divided by the cross-sectional area (second cross-sectional area) of the second resistance heater 2 perpendicular to the direction in which the two currents flow is maintained at 5 A / mm ² or less. Preferably, the second current density is maintained at 5 A / mm ² or less during time T2 and time T5, and more preferably, the second current density is maintained at 5 A / mm ² or less during time T3 and time T4. Ru. Preferably, the second current density is maintained at 4 A / mm ² or less, more preferably at 3 A / mm ² or less. For example, when the minimum value of the cross-sectional area of the second resistance heater 2 is 100 mm ² , the power supplied to the second resistance heater 2 is adjusted such that the current flowing through the second resistance heater 2 is 500 A or less. The power supplied to the second resistance heater 2 is, for example, 5 kW or more and 100 kW or less. In the step of growing the silicon carbide single crystal, the average temperature of the second resistance heater 2 may be a temperature between 2000 ° C. and 2400 ° C., and the temperature of the second resistance heater 2 may fluctuate. .

Preferably, in the step of growing the silicon carbide single crystal, the temperature of the first resistance heater 1 is 2000 ° C. or more and 2400 ° C. or less, and the value of the current (first current) flowing through the first resistance heater 1 is The value (first current density) divided by the cross-sectional area (first cross-sectional area) of the first resistance heater 1 perpendicular to the direction in which one current flows is maintained at 5 A / mm ² or less. Preferably, the first current density is maintained at 4 A / mm ² or less, more preferably at 3 A / mm ² or less. For example, when the minimum value of the cross-sectional area of the first resistance heater 1 is 100 mm ² , the power supplied to the first resistance heater 1 is adjusted such that the current flowing through the first resistance heater 1 is 500 A or less. The power supplied to the first resistance heater 1 is, for example, 5 kW or more and 100 kW or less. In the step of growing the silicon carbide single crystal, the average temperature of the first resistance heater 1 may be any temperature between 2000 ° C. and 2400 ° C., and the temperature of the first resistance heater 1 may fluctuate. .

Preferably, the temperature of the third resistance heater 3 is 2000 ° C. or more and 2400 ° C. or less, and the value of the current (third current) flowing through the third resistance heater 3 is perpendicular to the direction in which the third current flows. The value (third current density) divided by the cross-sectional area (third cross-sectional area) of the third resistance heater 3 is maintained at 5 A / mm ² or less. Preferably, the third current density is maintained at 4 A / mm ² or less, more preferably at 3 A / mm ² or less. For example, when the minimum value of the cross-sectional area of the third resistance heater 3 is 100 mm ² , the power supplied to the third resistance heater 3 is adjusted such that the current flowing through the third resistance heater 3 is 500 A or less. The power supplied to the third resistance heater 3 is, for example, 5 kW or more and 100 kW or less. In the step of growing the silicon carbide single crystal, the average temperature of the third resistance heater 3 may be a temperature between 2000 ° C. and 2400 ° C., and the temperature of the third resistance heater 3 may fluctuate. .

  In the step of growing the silicon carbide single crystal, silicon carbide raw material 12 is maintained at a temperature at which silicon carbide is sublimed, and 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, for example, as follows. The temperature of the bottom surface 5b2 is measured using the lower radiation thermometer 9a. As shown in FIG. 12, 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 the desired temperature. If the temperature of the bottom surface 5b2 is higher than the desired temperature, for example, the first power supply 8a (see FIG. 4) is instructed to reduce the power supplied to the first resistance heater 1. Conversely, when the temperature of the bottom surface 5b2 is lower than the desired temperature, for example, the first power supply 8a (see FIG. 4) is instructed to increase the power supplied to the first resistance heater 1. That is, the first power supply 8 a supplies power to the first resistance heater 1 based on an instruction from the control unit. 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 temperature of the bottom surface 5b2 is controlled to a desired temperature by determining the power to be supplied to the first resistance heater 1 based on the temperature of the first resistance heater 1 measured by the lower radiation thermometer 9a. It may be done. 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 temperatures of both the first resistance heater 1 and the bottom surface 5b2.

  Similarly, by determining the power supplied to the second resistance heater 2 based on the temperature of the side surface 5b1 measured by the side radiation thermometer 9b, the temperature of the side surface 5b1 is controlled to a desired temperature. Alternatively, the power supplied to the second resistance heater 2 is determined based on the temperature of the second resistance heater 2 measured by the side radiation thermometer 9b, whereby the temperature of the side surface 5b1 becomes the 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 2 based on the temperature of both the second resistance heater 2 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, whereby 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 temperatures 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 rises from the pressure P2 to the pressure P1 (see FIG. 11). By the pressure in the chamber 6 rising, the sublimation of the silicon carbide raw material 12 is suppressed. Thereby, the step of growing the silicon carbide single crystal is substantially completed. At time T6, the heating of crucible 5 is stopped and crucible 5 is cooled. After the temperature of crucible 5 reaches around room temperature, silicon carbide single crystal 20 is taken out of crucible 5.

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

The manufacturing apparatus 100 of the silicon carbide single crystal which concerns on this Embodiment is equipped with the crucible 5, the resistance heater 2, and the power supply 7a. 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 2 is provided outside the crucible 5 and is made of carbon. The power supply 7 a is configured to be able to supply power to the resistance heater 2. When the temperature of the resistive heater 2 reaches a certain temperature between 2000 ° C. and 2400 ° C. by supplying power to the resistive heater 2 by the power supply 7 a, the value of the current flowing through the resistive heater 2 is the direction of the current flow The power supply 7a and the resistance heater 2 are configured such that the value divided by the cross-sectional area of the resistance heater 2 perpendicular to the direction is 5 A / mm ² or less. Thereby, the deterioration of the resistance heater 2 can be suppressed.

According to the manufacturing apparatus 100 of the silicon carbide single crystal according to the present embodiment, the density of the carbon atoms constituting the resistance heater 2 is 1.7 g / cm ³ or more 1.9 g / cm ³ or less.

  Furthermore, according to the manufacturing apparatus 100 of the silicon carbide single crystal which concerns on this Embodiment, the resistivity of the carbon which comprises the resistance heater 2 is 1200 m ohm * cm or more.

Furthermore, according to the silicon carbide single crystal manufacturing apparatus 100 according to this embodiment, the cross-sectional area of the resistive heater 2 is 100 mm ² or more 500 mm ² or less.

The silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment includes a crucible 5, a first resistance heater 1, a second resistance heater 2, a third resistance heater 3, a first power supply 8a, and a second power supply. 7a and a third power supply 14a. 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 first resistance heater 1 is provided to face the bottom surface 5b2 and is made of carbon. The second resistance heater 2 is configured to surround the side surface 5b1 and is made of carbon. The third resistance heater 3 is provided to face the top surface 5a1 and is made of carbon. The first power supply 8 a is configured to be able to supply power to the first resistance heater 1. The second power supply 7 a is configured to be able to supply power to the second resistance heater 2. The third power supply 14 a is configured to be able to supply power to the third resistance heater 3. When power is supplied to the first resistance heater 1 by the first power supply 8 a and the temperature of the first resistance heater 1 reaches a certain temperature between 2000 ° C. and 2400 ° C., the first flow in the first resistance heater 1 occurs. The first power supply 8a and the first resistance heater 1 so that the value obtained by dividing the value of the current by the first cross-sectional area of the first resistance heater 1 perpendicular to the direction in which the first current flows is 5 A / mm ² or less. Is configured. When power is supplied to the second resistance heater 2 by the second power supply 7 a and the temperature of the second resistance heater 2 reaches a certain temperature between 2000 ° C. and 2400 ° C., the second flowing in the second resistance heater 2 The second power supply 7a and the second resistance heater 2 are configured such that the value obtained by dividing the value of the current by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is 5A / mm ² or less. It is configured. When power is supplied to the third resistance heater 3 by the third power supply 14 a and the temperature of the third resistance heater 3 reaches a certain temperature between 2000 ° C. and 2400 ° C., the third flowing in the third resistance heater 3 The third power supply 14 a and the third resistance heater 3 are set such that the value obtained by dividing the value of the current by the third cross-sectional area of the third resistance heater 3 perpendicular to the direction in which the third current flows is 5 A / mm ² or less. Is configured. Each of the first cross sectional area, the second cross sectional area, and the third cross sectional area is 100 mm ² or more and 500 mm ² or less. The density of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is 1200 mΩ · cm or more. Thereby, the deterioration of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 can be suppressed.

According to the method for manufacturing a silicon carbide single crystal in accordance with 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 And the resistance heater 2 provided outside the crucible 5 and made of carbon, the raw material 12 provided inside the crucible 5, and the material 12 facing the raw material 12 inside the crucible 5 The seed crystal 11 is prepared. By subliming the raw material 12 with the resistance heater 2, the silicon carbide single crystal 20 is grown on the seed crystal 11. In the step of growing silicon carbide single crystal 20, the value obtained by dividing the value of the current flowing through resistance heater 2 by the cross-sectional area of resistance heater 2 perpendicular to the current flow direction is maintained at 5 A / mm ² or less Ru. Thereby, the deterioration of the resistance heater 2 can be suppressed.

  Further, according to the method for producing a silicon carbide single crystal according to the present embodiment, the temperature of resistance heater 2 is maintained at 2000 ° C. or more and 2400 ° C. or less in the step of growing silicon carbide single crystal 20.

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

According to the method for manufacturing a silicon carbide single crystal in accordance with the present embodiment, chamber 6, and provided inside top of chamber 6, top surface 5a1, bottom surface 5b2 opposite to top surface 5a1, and top surface 5a1 A crucible 5 having a cylindrical side surface 5b1 located between the bottom surface 5b2 and the first resistance heater 1 provided facing the bottom surface 5b2 inside the chamber 6 and made of carbon, and the chamber 6 A second resistance heater 2 configured to surround side surface 5b1 in the interior and configured from carbon, and a third resistance heater 3 provided to face top surface 5a1 in the interior of chamber 6 and configured from carbon The raw material 12 provided inside the crucible 5 and the seed crystal 11 provided facing the raw material 12 inside the crucible 5 are prepared. By sublimating the raw material 12, a silicon carbide single crystal 20 is grown on the seed crystal 11. In the step of growing the silicon carbide single crystal 20, the temperature of the first resistance heater 1 is 2000 ° C. or more and 2400 ° C. or less, and the value of the first current flowing through the first resistance heater 1 is set in the direction of flowing the first current. The value divided by the first cross-sectional area of the first resistance heater 1 perpendicular thereto is maintained at 5 A / mm ² or less, the temperature of the second resistance heater 2 is 2000 ° C. or more and 2400 ° C. or less, and the second resistance heater The value obtained by dividing the value of the second current flowing to 2 by the second cross-sectional area of the second resistance heater 2 perpendicular to the direction in which the second current flows is maintained at 5 A / mm ² or less. The temperature of the third resistance heater 3 is 2000 ° C. or more and 2400 ° C. or less, and the value of the third current flowing through the third resistance heater 3 is the third resistance heater 3 perpendicular to the direction in which the third current flows. The value divided by the three cross-sectional areas is maintained at 5 A / mm ² or less. The pressure of the chamber 6 is maintained at 0.5 kPa or more and 2 kPa or less. Thereby, the deterioration of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 can be suppressed.

First, a resistive heater (Samples 1 to 7) made of graphite having a density of 1.75 g / cm ³ and a resistive heater made of carbon having a density of 1.85 g / cm ³ (Samples 8 to 14) And prepared. The resistance of each resistive heater (samples 1-14) before supplying the current was measured. Next, current was supplied to each resistance heater (samples 1 to 14) for 100 hours in a temperature environment of about 2200 ° C. The current densities of the resistance heaters according to Samples 1 to 7 are 2 A / mm ² , 3 A / mm ² , 4 A / mm ² , 5 A / mm ² , 6 A / mm ² , 7 A / mm ² and 8 A / mm ² , respectively. Thus, the current flowing to the resistance heater was adjusted. Similarly, the current densities of the resistance heaters according to Samples 8 to 14 are 2A / mm ² , 3A / mm ² , 4A / mm ² , 5A / mm ² , 6A / mm ² , 7A / mm ² and 8A / mm, respectively. ^The current supplied to the resistance heater was adjusted to be ² . The current density of the resistive heater was adjusted by changing the current supplied to the resistive heater without changing the cross-sectional area of the resistive heater. Specifically, the cross-sectional area of the resistance heater according to Samples 1 to 14 was 150 mm ² . The currents supplied to the resistance heaters according to Samples 1 to 7 were respectively 300A, 450A, 600A, 750A, 900A, 1050A and 1200A. Similarly, the currents supplied to the resistance heaters according to Samples 8 to 14 were 300A, 450A, 600A, 750A, 900A, 1050A, and 1200A, respectively.

  After supplying power for 100 hours, the resistance of each resistive heater (samples 1 to 14) was measured. After powering, the resistance of all the resistive heaters increased. The resistance increase rate (%) after 100 hours of energization was calculated by dividing the difference between the resistance of the resistive heater after power supply and the resistance of the resistive heater before power supply by the resistance of the resistive heater before power supply. Note that when power is supplied to the resistance heater for a long time, carbon constituting the resistance heater is degraded. In particular, if the temperature of the resistance heater is, for example, 2000 ° C. or more and 2400 ° C. or less, and the pressure of the chamber in which the resistance heater is disposed is, for example, about 1 kPa, the carbon constituting the resistance heater sublimes. The heater is degraded. As the carbon constituting the resistive heater sublimes, the resistance of the resistive heater increases. In the step of growing the silicon carbide single crystal, silicon is generated by sublimation of the silicon carbide raw material. The carbon is etched by silicon. Therefore, in the step of growing the silicon carbide single crystal, it is considered that the deterioration of the resistance heater is promoted.

FIG. 13 is a diagram showing the relationship between the rate of increase in resistance of the resistance heater 100 hours after energization and the current density of the resistance heater while the resistance heater is energized. The vertical axis in FIG. 13 indicates the resistance increase rate (%) of the resistance heater after 100 hours of energization, and the horizontal axis indicates the current density (A / mm ² ) of the resistance heater while the resistance heater is energized. Is shown. The allowable value of the resistance increase rate (%) of the resistance heater after 100 hours of energization is 1% or less. The diamond symbols indicate resistive heaters (samples 1 to 7) made of carbon having a density of 1.75 g / cm ³ . The square symbol indicates a resistive heater (samples 8-14) composed of carbon with a density of 1.85 g / cm ³ .

As shown in FIG. 13, when the current density of the resistive heater was 5 A / mm ² or less, the rate of increase in resistance of the resistive heater after 100 hours of energization was 1% or less. In addition, when the current density of the resistance heater became larger than 5 A / mm ² , the rate of increase in resistance of the resistance heater increased rapidly after 100 hours of energization. When comparing at the same current density, the resistance heater with high carbon density had a smaller increase in resistance than the resistance heater with low carbon density. From the above results, it was proved that the deterioration of the resistance heater can be effectively suppressed by setting the current density of the resistance heater to 5 A / mm ² or less.

  The embodiments and examples disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

1 first resistance heater 1a upper surface 1b lower surface 1x first portion 2 second resistance heater (resistance heater)
2a first surface 2b second surface 2c third surface 2d fourth surface 2x second portion 3 third resistance heater 3x third portion 4x fourth portion 5 5a1 top surface 5a pedestal 5a2 seed crystal holding surface 5b2 bottom surface 5b housing portion 5b1 Side 6 chamber 6a, 6b, 6c windows 7, 8 and 14 electrode 7a second power supply (power supply)
8a 1st power supply 9a lower radiation thermometer (radiation thermometer)
9b Side radiation thermometer 9c Top radiation thermometer 10x Heater unit 11 Seed crystal 11a Back surface 11b, 12a Surface 12 Raw material (silicon carbide raw material)
14a Third power supply 20 Silicon carbide single crystal 100 Production equipment A1, A2 Temperature CS Section P1, P2 Pressure T0, T1, T2, T3, T4, T5, T6 Time W1, W2 width

An apparatus for manufacturing a silicon carbide single crystal according to an aspect of the present invention includes a crucible, a first resistance heater, a second resistance heater, a third resistance heater, a first power supply, a second power supply, and a third power supply. And 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 first resistance heater is provided facing the bottom and is made of carbon. The second resistive heater is configured to surround the side surface and is made of carbon. The third resistance heater is provided facing the top surface and is made of carbon. The first power supply is configured to be able to supply power to the first resistance heater. The second power supply is configured to be able to supply power to the second resistance heater. The third power supply is configured to be able to supply power to the third resistance heater. When the first power supply supplies power to the first resistance heater and the temperature of the first resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the first current flowing to the first resistance heater is The first resistance heater is configured such that the value divided by the first cross-sectional area of the first resistance heater perpendicular to the direction in which the first current flows is 5 A / mm ² or less. When the second power supply supplies power to the second resistance heater and the temperature of the second resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the second current flowing to the second resistance heater is The second resistance heater is configured such that the value divided by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is 5 A / mm ² or less. When the third power supply supplies power to the third resistance heater and the temperature of the third resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the third current flowing to the third resistance heater is The third resistance heater is configured such that the value divided by the third cross-sectional area of the third resistance heater perpendicular to the direction in which the third current flows is 5 A / mm ² or less. Each of the first cross sectional area, the second cross sectional area, and the third cross sectional area is 100 mm ² or more and 500 mm ² or less. The density of carbon constituting each of the first resistance heater, the second resistance heater, and the third resistance heater is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater, the second resistance heater and the third resistance heater is 1200 μΩ · cm or more.

(3) In the apparatus for manufacturing a silicon carbide single crystal according to the above (1) or (2), preferably, the resistivity of carbon constituting the resistance heater is 1200 μΩ · cm or more.

(5) The apparatus for manufacturing a silicon carbide single crystal according to one aspect of the present invention includes a crucible, a first resistance heater, a second resistance heater, a third resistance heater, a first power supply, and a second power supply. And a third power source. 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 first resistance heater is provided facing the bottom and is made of carbon. The second resistive heater is configured to surround the side surface and is made of carbon. The third resistance heater is provided facing the top surface and is made of carbon. The first power supply is configured to be able to supply power to the first resistance heater. The second power supply is configured to be able to supply power to the second resistance heater. The third power supply is configured to be able to supply power to the third resistance heater. When the first power supply supplies power to the first resistance heater and the temperature of the first resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the first current flowing to the first resistance heater is The first power supply and the first resistance heater are configured such that the value divided by the first cross-sectional area of the first resistance heater perpendicular to the direction in which the first current flows is 5 A / mm ² or less. When the second power supply supplies power to the second resistance heater and the temperature of the second resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the second current flowing to the second resistance heater is The second power supply and the second resistance heater are configured such that the value divided by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is 5 A / mm ² or less. When the third power supply supplies power to the third resistance heater and the temperature of the third resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the value of the third current flowing to the third resistance heater is The third power supply and the third resistance heater are configured such that the value divided by the third cross-sectional area of the third resistance heater perpendicular to the direction in which the third current flows is 5 A / mm ² or less. Each of the first cross sectional area, the second cross sectional area, and the third cross sectional area is 100 mm ² or more and 500 mm ² or less. The density of carbon constituting each of the first resistance heater, the second resistance heater, and the third resistance heater is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater, the second resistance heater and the third resistance heater is 1200 μΩ · cm or more. Thereby, deterioration of the first resistance heater, the second resistance heater, and the third resistance heater can be suppressed.

Each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is made of carbon. The density of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is, for example, 1.6 g / cm ³ or more and 2.0 g / cm ³ or less, preferably 1.7 g / Cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is, for example, 1100 μΩ · cm or more and 1800 μΩ · cm or less, preferably 1200 μΩ · cm or more It is less than 1700 μΩ · cm.

Furthermore, according to the manufacturing apparatus 100 of the silicon carbide single crystal which concerns on this Embodiment, the resistivity of the carbon which comprises the resistance heater 2 is 1200 microhm * cm or more.

The silicon carbide single crystal manufacturing apparatus 100 according to the present embodiment includes a crucible 5, a first resistance heater 1, a second resistance heater 2, a third resistance heater 3, a first power supply 8a, and a second power supply. 7a and a third power supply 14a. 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 first resistance heater 1 is provided to face the bottom surface 5b2 and is made of carbon. The second resistance heater 2 is configured to surround the side surface 5b1 and is made of carbon. The third resistance heater 3 is provided to face the top surface 5a1 and is made of carbon. The first power supply 8 a is configured to be able to supply power to the first resistance heater 1. The second power supply 7 a is configured to be able to supply power to the second resistance heater 2. The third power supply 14 a is configured to be able to supply power to the third resistance heater 3. When power is supplied to the first resistance heater 1 by the first power supply 8 a and the temperature of the first resistance heater 1 reaches a certain temperature between 2000 ° C. and 2400 ° C., the first flow in the first resistance heater 1 occurs. The first power supply 8a and the first resistance heater 1 so that the value obtained by dividing the value of the current by the first cross-sectional area of the first resistance heater 1 perpendicular to the direction in which the first current flows is 5 A / mm ² or less. Is configured. When power is supplied to the second resistance heater 2 by the second power supply 7 a and the temperature of the second resistance heater 2 reaches a certain temperature between 2000 ° C. and 2400 ° C., the second flowing in the second resistance heater 2 The second power supply 7a and the second resistance heater 2 are configured such that the value obtained by dividing the value of the current by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is 5A / mm ² or less. It is configured. Third power supply 1
The value of the third current flowing through the third resistance heater 3 when power is supplied to the third resistance heater 3 by 4a and the temperature of the third resistance heater 3 reaches a certain temperature between 2000 ° C. and 2400 ° C. a third power source 14a and the third resistor heater 3 is configured so that a value obtained by dividing the third cross-sectional area of the third resistor heater 3 perpendicular to the direction in which the third current flows is 5A / mm ² or less ing. Each of the first cross sectional area, the second cross sectional area, and the third cross sectional area is 100 mm ² or more and 500 mm ² or less. The density of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less. The resistivity of carbon constituting each of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 is 1200 μΩ · cm or more. Thereby, the deterioration of the first resistance heater 1, the second resistance heater 2 and the third resistance heater 3 can be suppressed.

Claims (9)

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 resistive heater provided outside the crucible and made of carbon;
A power supply configured to supply power to the resistance heater;
When the temperature of the resistive heater reaches a certain temperature between 2000 ° C. and 2400 ° C. by supplying power to the resistive heater by the power supply, the current flows the value of the current flowing through the resistive heater The apparatus for manufacturing a silicon carbide single crystal, wherein the power supply and the resistance heater are configured such that a value divided by a cross-sectional area of the resistance heater perpendicular to a direction is 5 A / mm ² or less. The manufacturing apparatus of the silicon carbide single crystal according to claim 1 whose density of said carbon which constitutes said resistance heater is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less.   The manufacturing apparatus of the silicon carbide single crystal according to claim 1 or 2 whose resistivity of said carbon which constitutes said resistance heater is 1200 mohm-cm or more. Wherein the cross-sectional area of the resistive heater is 100 mm ² or more 500 mm ² or less, the manufacturing apparatus of the silicon carbide single crystal according to any one of claims 1 to 3. 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 disposed facing the bottom surface and made of carbon;
A second resistive heater configured to surround the side surface and made of carbon;
A third resistance heater disposed facing the top surface and made of carbon;
A first power supply configured to be able to supply power to the first resistance heater;
A second power supply configured to be able to supply power to the second resistance heater;
And a third power supply configured to be capable of supplying power to the third resistance heater,
When power is supplied to the first resistance heater by the first power source and the temperature of the first resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the first current flows to the first resistance heater. The first power source and the first resistor are configured such that the value obtained by dividing the value of the current by the first cross-sectional area of the first resistance heater perpendicular to the direction in which the first current flows is 5 A / mm ² or less. The heater is configured,
When power is supplied to the second resistance heater by the second power supply and the temperature of the second resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C., the second current flows to the second resistance heater. The second power supply and the second resistance such that the value obtained by dividing the value of the current by the second cross-sectional area of the second resistance heater perpendicular to the direction in which the second current flows is 5 A / mm ² or less. The heater is configured,
When the temperature of the third resistance heater reaches a certain temperature between 2000 ° C. and 2400 ° C. by supplying electric power to the third resistance heater by the third power supply, the third flowing in the third resistance heater The third power supply and the third resistance such that a value obtained by dividing the value of the current by the third cross-sectional area of the third resistance heater perpendicular to the direction in which the third current flows is 5 A / mm ² or less. The heater is configured,
Each of the first cross-sectional area, the second cross-sectional area, and the third cross-sectional area is 100 mm ² or more and 500 mm ² or less,
The density of carbon constituting each of the first resistance heater, the second resistance heater, and the third resistance heater is 1.7 g / cm ³ or more and 1.9 g / cm ³ or less,
The manufacturing apparatus of the silicon carbide single crystal whose resistivity of carbon which comprises each of a said 1st resistance heater, a said 2nd resistance heater, and a said 3rd resistance heater is 1200 m (ohm) * 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 resistive heater provided outside the crucible and made of carbon;
The raw material provided in the inside of the said cage,
Preparing a seed crystal provided facing the raw material inside the crucible;
And b. Growing the silicon carbide single crystal on the seed crystal by sublimating the raw material with the resistance heater.
In the step of growing the silicon carbide single crystal, the value obtained by dividing the value of the current flowing through the resistance heater by the cross-sectional area of the resistance heater perpendicular to the current flow direction is maintained at 5 A / mm ² or less A method for producing a silicon carbide single crystal.   The method for producing a silicon carbide single crystal according to claim 6, wherein in the step of growing the silicon carbide single crystal, a temperature of the resistance heater is maintained at 2000 ° C or more and 2400 ° C or less. Further comprising the step of preparing a chamber for containing the crucible.
The method for producing a silicon carbide single crystal according to claim 6 or 7, wherein the pressure of the chamber in the step of growing the silicon carbide single crystal 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 disposed facing the bottom surface inside the chamber and made of carbon;
A second resistance heater configured to surround the side surface inside the chamber and made of carbon;
A third resistance heater disposed facing the top surface inside the chamber and made of carbon;
The raw material provided in the inside of the said cage,
Preparing a seed crystal provided facing the raw material inside the crucible;
And b. Growing the silicon carbide single crystal on the seed crystal by sublimating the raw material,
In the step of growing the silicon carbide single crystal,
The temperature of the first resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the value of the first current flowing through the first resistance heater is perpendicular to the direction in which the first current flows. The value divided by the first cross-sectional area is maintained at 5 A / mm ² or less,
The temperature of the second resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the value of the second current flowing through the second resistance heater is perpendicular to the direction in which the second current flows. The value divided by the second cross-sectional area is maintained at 5 A / mm ² or less,
The temperature of the third resistance heater is 2000 ° C. or more and 2400 ° C. or less, and the value of the third current flowing through the third resistance heater is perpendicular to the direction in which the third current flows. A method for producing a silicon carbide single crystal, wherein a value divided by a third cross-sectional area is maintained at 5 A / mm ² or less, and a pressure of the chamber is maintained at 0.5 kPa or more and 2 kPa or less.

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