JP2014024736A - Aluminum nitride single crystal producing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum nitride single crystal producing device and method which can facilitate the positioning of a seed substrate relative to a holding member, and can prevent the movement of the seed substrate during crystal growth.SOLUTION: A holding member 35 is integrally formed with a support body 33 formed of a ring-shaped projection projecting upward from the upper surface 35a of the holding member 35. The internal diameter of the ring-shaped projection forming the support body 33 is equal to or slightly larger than the diameter of the seed substrate 14. By fitting the seed substrate 14 inside the ring-shaped projection of the support body 33, the peripheral surface 14b of the seed substrate 14 abuts on a step 33a of the support body 33 to be surrounded thereby.

Description

  The present invention relates to an aluminum nitride (AlN) manufacturing apparatus and manufacturing method, and more particularly to a technique for preventing misalignment of a seed substrate.

  Aluminum nitride semiconductors have a very high thermal conductivity and are very advantageous for diffusing heat. Examples of the method for producing the aluminum nitride single crystal include a flux method for the solution method and a metal organic vapor phase growth method, a hydride vapor deposition method, a sublimation method for the vapor phase method, and the like. In particular, the sublimation method is a powerful method for producing a bulk crystal because the growth rate is generally high.

As an apparatus for producing an aluminum nitride single crystal by a conventional sublimation method, for example, an apparatus for producing an aluminum nitride single crystal described in Patent Document 1 is shown in FIG.
A conventional aluminum nitride single crystal manufacturing apparatus 50 includes a crucible (crystal growth vessel) 52 having an opening at the top, a lid 53 provided near the opening, and a holding provided below the lid 53. A member 55 and a seed substrate 54 sandwiched between the lid 53 and the holding member 55 are provided.
The entire crystal growth space 57 constituted by the crucible 55 and the lid 53 is disposed in a space formed by the graphite outer crucible 58 and the graphite outer lid 59 placed on the upper surface of the outer crucible 58. The outer crucible 58 and the crucible 52 are fixed in the crystal growth furnace 51. A raw material 56 such as aluminum nitride powder is stored in the inner bottom portion of the crucible 52, and a portion of the seed substrate 54 that does not contact the holding member 55 faces the raw material 56.

  When growing aluminum nitride single crystal AlN, the crucible (crystal growth vessel) 52 is heated to about 2000 ° C. by the heating means 51 to sublimate the raw material 56 mainly composed of aluminum nitride. As a result, a sublimation gas having an aluminum nitride composition is generated and transferred onto the seed substrate 54. Then, aluminum nitride is recrystallized (precipitated) on one main surface (hereinafter referred to as a crystal growth surface) of the seed substrate 54 to grow as aluminum nitride single crystal AlN.

  However, the conventional aluminum nitride single crystal manufacturing apparatus disclosed in Patent Document 1 described above has a configuration in which the seed substrate is simply sandwiched between the lid and the holding member. In such a configuration, when the seed substrate is placed on the holding member or when an aluminum nitride single crystal is grown on the seed substrate, the seed substrate may move from a predetermined position due to vibration or a sublimation gas flow. there were. When the seed substrate deviates from a predetermined position, the aluminum nitride single crystal grows asymmetrically with respect to the seed substrate, and there is a possibility that the yield is deteriorated when the substrate is obtained by slicing or a slice failure is caused. Further, when the seed substrate moves during crystal growth, the crystallinity of the grown crystal is deteriorated, and it becomes difficult to obtain an aluminum nitride single crystal having good crystallinity.

JP 2011-132079 A

  The present invention has been made in view of such a conventional situation, and facilitates the alignment of the seed substrate with respect to the holding member, and can prevent the movement of the seed substrate during crystal growth. An object of the present invention is to provide a crystal manufacturing apparatus and a manufacturing method.

In order to solve the above-described problems, some aspects of the present invention provide the following aluminum nitride single crystal manufacturing apparatus and manufacturing method.
That is, the apparatus for producing an aluminum nitride single crystal of the present invention includes a crystal growth container, a seed substrate on which an aluminum nitride single crystal is grown, the seed substrate held on one surface, and an outer portion of the seed substrate at the center. A holding member having a through opening smaller than the diameter,
It has a support body arranged along the peripheral edge of the seed substrate so that the movement of the seed substrate may be suppressed on the one surface of the holding member.

  The support is a member A that has a concave shape from the one surface of the holding member.

  The member A is continuously arranged so as to surround the periphery of the seed substrate.

  A plurality of the members A are intermittently arranged so as to surround the periphery of the seed substrate.

  The support is a member B that is convex from the one surface of the holding member.

  The member B is continuously arranged so as to surround the periphery of the seed substrate.

  A plurality of the members B are intermittently provided so as to surround the periphery of the seed substrate.

  The holding member and the support are integral members.

The method for producing an aluminum nitride single crystal of the present invention is a method for producing an aluminum nitride single crystal by a sublimation method,
A crystal growth container; a seed substrate for growing an aluminum nitride single crystal on one surface; a holding member having a through opening smaller than the outer diameter of the seed substrate at a central portion; and holding the seed substrate on one surface; and the holding member A support body disposed along the periphery of the seed substrate so as to suppress the movement of the seed substrate,
A sublimation gas containing aluminum nitride is deposited on the seed substrate while suppressing the movement of the seed substrate by the support, thereby obtaining an aluminum nitride single crystal.

  According to the manufacturing apparatus and manufacturing method of an aluminum nitride single crystal of the present invention, it is possible to prevent the seed substrate from moving in the direction along the crystal growth surface during crystal growth. That is, when the seed substrate fitted in the support is moved in the direction along the crystal growth surface, the peripheral surface is in contact with the step of the support, so that it is sure to move in the direction along the crystal growth surface. It becomes possible to prevent. As a result, it is possible to prevent deterioration of crystallinity of the grown crystal due to movement of the seed substrate, and to produce an aluminum nitride single crystal having good crystallinity.

  In addition, the support can accurately and easily position the placement position of the seed substrate when placing the seed substrate on the holding member. That is, since the support is formed, for example, at a position in contact with the peripheral surface of the seed substrate, the seed substrate is placed at the correct placement position of the seed substrate on the holding member simply by fitting the seed substrate into the support. It becomes possible to position and mount accurately and easily.

It is a schematic structure figure showing typically an example of the manufacture device of the aluminum nitride single crystal concerning a 1st embodiment of the present invention. It is the perspective view and sectional drawing explaining the holding member which concerns on 1st Embodiment of this invention. It is a perspective view explaining the holding member concerning a 2nd embodiment of the present invention. It is a perspective view explaining the holding member concerning a 3rd embodiment of the present invention. It is a perspective view explaining the holding member which concerns on 4th Embodiment of this invention. It is a schematic block diagram which shows typically an example of the manufacturing apparatus of the aluminum nitride single crystal which concerns on 5th Embodiment of this invention. It is a schematic block diagram which shows typically an example of the manufacturing apparatus of the conventional aluminum nitride single crystal.

Hereinafter, the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 is a schematic configuration diagram schematically showing an example of an aluminum nitride single crystal manufacturing apparatus according to the first embodiment of the present invention. The apparatus for producing an aluminum nitride single crystal of this embodiment is an apparatus for growing an aluminum nitride single crystal by sublimating and recrystallizing aluminum nitride on a seed substrate by a sublimation method.

  The apparatus 10 for producing an aluminum nitride single crystal according to this embodiment includes a crystal growth furnace 20. The crystal growth furnace 20 includes a crystal growth vessel (crucible) 11 having an opening at the top, an outer lid 19 provided at the opening, a lid 13 provided below the outer lid 19 and a holding unit. And a member 15. A seed substrate 14 is sandwiched between the lid 13 and the holding member 15. Further, the outside of the crystal growth space 17 composed of the crystal growth vessel 11 and the outer lid 19 is covered with a furnace body storage vessel 18 made of graphite or the like. A raw material 12 such as aluminum nitride powder is accommodated in the inner bottom of the crystal growth vessel 11. In addition, although the cover body 13 does not need to provide in particular, the rocking | fluctuation to the vertical direction of the seed board | substrate 14 can be suppressed by providing the cover body 13. FIG.

  The seed substrate 14 for crystal growth is, for example, a plate-like or disc-like SiC single crystal, AlN single crystal, AlN / SiC single crystal (an AlN single crystal film having a thickness of about 200 to 500 μm is heterogeneously formed on the SiC single crystal. Single crystal grown).

  Furthermore, a plurality of heating means 21 for heating the furnace body storage container 18, the crystal growth container 11, the raw material 12, and the seed substrate 14 disposed inside the crystal growth furnace 20 along the outer periphery of the crystal growth furnace 20. Is provided. The heating means 21 is not particularly limited, and conventionally known ones such as high frequency induction heating (high frequency coil), resistance heating and infrared heating can be used. The heating temperature can be controlled by adjusting the heating means 21 while measuring the surface temperature of the furnace container 18 with a radiation thermometer (not shown).

  In addition, a pressure adjusting mechanism (not shown) that can introduce an inert gas such as nitrogen gas and adjust the crystal growth space 17 to a predetermined gas pressure is further provided outside the crystal growth furnace 20. Is preferred.

  The crystal growth vessel 11, the outer lid 19 and the holding member 15 are made of graphite, boron nitride, aluminum nitride, gallium nitride, silicon carbide, silicon nitride, molybdenum, tungsten, tantalum, molybdenum carbide, zirconium carbide, tungsten carbide, tantalum carbide, It is formed from at least one of molybdenum nitride, zirconium nitride, tungsten nitride, and tantalum nitride. Since these materials have thermal resistance at a high temperature of about 2000 ° C. during crystal growth of an aluminum nitride single crystal, they are preferable as materials for the crystal growth container 11, the outer lid 19, and the holding member 15.

  In addition, a raw material 12 such as aluminum nitride powder is directly stored in the inner bottom portion of the crystal growth vessel 11, and a seed substrate 14 is installed between the outer lid 19 and the holding member 15. It is exposed to an aluminum nitride sublimation gas suitable for bulk crystal growth to be obtained. Therefore, the material constituting the crystal growth vessel 11, the outer lid body 19, and the holding member 15 is preferably one that is not subject to corrosion by the sublimation gas of aluminum nitride.

In addition, in order to prevent contamination of aluminum nitride single crystal AlN (contamination due to solid solution) from the materials constituting the crystal growth vessel 11, the outer lid 19 and the holding member 15, a metal which is greatly different from the ionic radius of aluminum The simple substance or its nitride or carbide is desirable. Therefore, among the materials described above as the materials of the crystal growth vessel 11, the outer lid body 19, and the holding member 15, in particular, molybdenum, tungsten, tantalum, molybdenum nitride, tungsten nitride, tantalum nitride, molybdenum carbide, tungsten carbide, and tantalum carbide are more. preferable.
Note that it is not preferable to use an oxide because the released oxygen forms an aluminum oxynitride (AlON) layer in the aluminum nitride crystal and inhibits the crystal growth of the aluminum nitride.

FIG. 2 is a partially broken perspective view and a sectional view showing the holding member.
The holding member 15 is installed on the peripheral edge 11a of the crystal growth container 11 so as to cover the opening of the crystal growth container 11, and the seed substrate 14 and the lid 13 are arranged thereon (see FIG. 1).
The holding member 15 is integrally formed with a support 23 for suppressing the movement of the seed substrate 14 and positioning the placement position of the seed substrate 14. In the present embodiment, the support 23 is a member A that is recessed from the upper surface (one surface) 15a of the holding member 15, specifically, a seed substrate 14 that is dug downward from the upper surface (one surface) 15a. It consists of a circular groove with a diameter equal to or slightly larger than the diameter of

  Such a support body 23 is continuously arranged so as to surround the periphery of the seed substrate 14. Further, the support body 23 is dug from the upper surface 15a of the holding member 15 to a depth of a thickness t2 that is, for example, about half of the thickness t1 of the holding member 15. Then, by inserting the seed substrate 14 into the circular groove of the support 23, the peripheral surface 14 b of the seed substrate 14 comes into contact with and is surrounded by the step 23 a of the support 23.

  The diameter of the circular groove serving as the support 23 is optimal for the peripheral surface 14b of the seed substrate 14 and the step 23a of the support 23 after thermal expansion in consideration of the expansion of the seed substrate 14 due to the heating of the raw material 12. It is preferable to set the clearance.

  The height (that is, thickness t2) of the step 23a of the support 23 may be about half of the thickness t3 of the seed substrate 14, for example. It is also preferable to set the height of the step 23a to be approximately the same as the thickness t3 of the seed substrate 14. Further, the side surface in the vertical direction of the step 23a does not have to be vertical as a whole, and may include, for example, an inclined surface that is inclined so as to spread upward from the middle. This facilitates insertion of the seed substrate 14 into the circular groove of the support 23.

  Further, a through opening 24 having a predetermined diameter is formed from the center of the circular groove of the support 23. The through-opening 24 is formed so as to be smaller than the diameter of the circular groove forming the support 23, and includes an upper surface 15 a of the holding member 15 and a lower surface 15 b of the holding member 15 (that is, a surface facing the raw material 12). It penetrates.

  In the seed substrate 14 fitted in the circular groove forming the support 23, a part of the crystal growth surface 14 a facing the raw material 12 is exposed to the raw material 12 through the through opening 24. Then, the crystal growth surface 14a exposed by the through opening 24 is exposed to aluminum nitride vapor generated by heating the raw material 12, and an aluminum nitride single crystal AlN grows on the crystal growth surface 14a. The shape of the through-opening 24 is not particularly limited as long as it is smaller than the outer diameter of the seed substrate 14 and has a sufficient area on the seed substrate 14 on which crystals grow.

  The support 23 having such a configuration prevents the seed substrate 14 from moving in a direction along the crystal growth surface 14a. That is, the seed substrate 14 fitted in the circular groove of the support 23 is reliably prevented from moving in the direction along the crystal growth surface 14a because the peripheral surface 14b is in contact with the step 23a of the support 23. It becomes possible to do. Thereby, the deterioration of the crystallinity of the grown crystal due to the movement of the seed substrate 14 can be prevented, and an aluminum nitride single crystal having good crystallinity can be produced.

  In addition, the support 23 can accurately position the placement position of the seed substrate 14 when placing the seed substrate 14 on the holding member 15. That is, since the support body 23 is configured by a circular groove having a diameter that is the same as or slightly larger than the diameter of the seed substrate 14, the support member 23 can be mounted on the support member 15 by simply fitting the seed substrate 14 into the support body 23. The seed substrate 14 can be accurately and easily positioned and placed at the correct placement position of the seed substrate 14.

  In the present embodiment, a double container structure in which the crystal growth container 11 is installed inside the furnace body storage container 18 is illustrated, but the present invention is not limited to this form. Of course, a triple container structure in which another container or the like is disposed between the furnace body storage container 18 and the crystal growth container 11 may be used.

Second Embodiment
FIG. 3 is a partially broken perspective view showing a holding member of an apparatus for producing an aluminum nitride single crystal according to a second embodiment of the present invention.
In the present embodiment, the holding member 25 includes a plurality of support bodies (members A) 26, that is, a plurality of concave members A that are intermittently disposed so as to surround the periphery of the seed substrate 14. The inner diameter of the circular region surrounded by the plurality of supports 26 is the same as or slightly larger than the diameter of the seed substrate 14. By fitting the seed substrate 14 into the arc-shaped grooves of the plurality of supports 26, the peripheral surface 14 b of the seed substrate 14 comes into contact with and is surrounded by the step 26 a of the support 26.

  The inner diameter surrounded by the plurality of supports 26 is optimal for the peripheral surface 14b of the seed substrate 14 and the step 26a of the support 26 after thermal expansion in consideration of expansion of the seed substrate 14 due to heating of the raw material. It is preferable to set the clearance.

  The depth of the groove forming the support 26, that is, the height of the step 26a may be, for example, about half of the thickness of the seed substrate 14, and is preferably the same as the thickness of the seed substrate 14. Further, the side surface in the vertical direction of the step 26a does not need to be entirely vertical, and may include, for example, an inclined surface that is inclined so as to spread upward from the middle. This facilitates the insertion of the seed substrate 14 into the arc-shaped groove forming the support 26.

  Further, a through opening 27 having a predetermined diameter is formed from the center of the holding member 25. The through opening 27 passes through the upper surface 25a of the holding member 25 and the lower surface 25b of the holding member 25 (that is, the surface facing the raw material). Through the through opening 27, the crystal growth surface 14a of the seed substrate 14 is exposed toward the raw material.

  The support body 26 of such an embodiment also prevents the seed substrate 14 from moving in the direction along the crystal growth surface 14a. That is, since the peripheral surface 14b of the seed substrate 14 fitted in the plurality of supports 26 formed by intermittently forming arc-shaped grooves is in contact with the level difference 26a of the support 26, the seed substrate 14 is formed on the crystal growth surface 14a. It is possible to reliably prevent the movement in the direction along. Thereby, the deterioration of the crystallinity of the grown crystal due to the movement of the seed substrate 14 can be prevented, and an aluminum nitride single crystal having good crystallinity can be produced.

  Further, the support 26 can accurately position the placement position of the seed substrate 14 when placing the seed substrate 14 on the holding member 25. That is, the diameter of the region surrounded by the plurality of supports 26 is the same as or slightly larger than the diameter of the seed substrate 14, so the seed substrate 14 is fitted into the region surrounded by the plurality of supports 26. It is possible to position and mount the seed substrate 14 accurately and easily at the correct mounting position of the seed substrate 14 in the holding member 25.

<Third Embodiment>
FIG. 4 is a partially broken perspective view showing a holding member of an aluminum nitride single crystal manufacturing apparatus according to a third embodiment of the present invention.
In the present embodiment, the holding member 35 is formed by continuously arranging the support 33, that is, the member B having a convex shape from the upper surface (one surface) 35 a of the holding member 35 so as to surround the periphery of the seed substrate 14. Specifically, a support 33 made of a ring-shaped protrusion protruding upward from an upper surface (one surface) 35 a of the holding member (member B) 35 is formed integrally with the holding member 35. The inner diameter of the ring-shaped protrusion forming the support 33 is the same as or slightly larger than the diameter of the seed substrate 14. By inserting the seed substrate 14 into the ring-shaped protrusion of the support 33, the peripheral surface 14 b of the seed substrate 14 abuts on and is surrounded by the step 33 a of the support 33.

  Note that the inner diameter of the ring-shaped ridge that is the support 23 is such that the peripheral surface 14b of the seed substrate 14 and the step 33a of the support 33 after thermal expansion take into account the expansion of the seed substrate 14 due to heating of the raw material. It is preferable to set so as to obtain an optimum clearance.

  Further, the support 33 may be formed integrally with the holding member 35, or may have a structure in which a ring-shaped protrusion forming a separately formed support is bonded or welded to the upper surface of the holding member. .

  The height of the protrusion forming the support 33, that is, the height of the step 33a may be, for example, about half of the thickness of the seed substrate 14, and is preferably the same as the thickness of the seed substrate 14. Further, the side surface in the vertical direction of the step 33a does not need to be entirely vertical, and may include, for example, an inclined surface that is inclined so as to spread upward from the middle. This facilitates the insertion of the seed substrate 14 into the ring-shaped protrusion that forms the support 33.

  Further, a through opening 34 having a predetermined diameter is formed from the center of the holding member 35. The through-opening 34 is formed to be smaller than the inner diameter of the ring-shaped protrusion forming the support 33, and the upper surface 35a of the holding member 35 and the lower surface 35b of the holding member 35 (that is, the surface facing the raw material). And penetrates. Through the through opening 34, the crystal growth surface 14a of the seed substrate 14 is exposed toward the raw material.

  The support 33 in such an embodiment also prevents the seed substrate 14 from moving in the direction along the crystal growth surface 14a. That is, since the peripheral surface 14b of the seed substrate 14 fitted in the ring-shaped protrusion integrally formed on the upper surface 35a of the support 33 is in contact with the step 33a of the support 33, the crystal growth surface 14a It is possible to reliably prevent movement in the direction along the line. Thereby, the deterioration of the crystallinity of the grown crystal due to the movement of the seed substrate 14 can be prevented, and an aluminum nitride single crystal having good crystallinity can be produced.

  Further, the support 33 can accurately position the placement position of the seed substrate 14 when placing the seed substrate 14 on the holding member 35. That is, since the support 33 is formed by a ring-shaped protrusion having an inner diameter that is the same as or slightly larger than the diameter of the seed substrate 14, simply inserting the seed substrate 14 into the support 33, The seed substrate 14 can be accurately and easily positioned and placed at the correct placement position of the seed substrate 14 on the holding member 35.

<Fourth embodiment>
FIG. 5 is a partially broken perspective view showing a holding member of an aluminum nitride single crystal manufacturing apparatus according to a fourth embodiment of the present invention.
In the present embodiment, the holding member 45 is formed by intermittently arranging the support 43, that is, the member B having a convex shape from the upper surface (one surface) 45 a of the holding member 45 so as to surround the periphery of the seed substrate 14. Specifically, a plurality of support bodies 43 formed of ring-shaped protrusions protruding upward from the upper surface (one surface) 45a of the holding member (member B) 45 are formed along the periphery of the seed substrate. The support 43 may be disposed on the upper surface (one surface) 45a of the holding member 45 so as to be separated from each other at least at three or more locations. When two or more holding members 45 are disposed outside the periphery of the seed substrate 14, the remaining supports 43 are also disposed outside the periphery of the seed substrate 14. Accordingly, the plurality of supports 43 are intermittently arranged so as to surround the periphery of the seed substrate 14 along the virtual circle R having a diameter that is the same as or slightly larger than the diameter of the seed substrate 14.

  The height of each protrusion constituting the support 43 may be, for example, about half the thickness of the seed substrate 14, and is preferably set to the same level as the thickness of the seed substrate 14. The shape of each protrusion constituting the support 43 is not limited to the shape along a part of the periphery of the seed substrate 14 as shown in FIG. 3, for example, a cylindrical protrusion, a protrusion such as a triangular prism or a quadrangular prism, etc. It may be.

  Further, a through opening 44 having a predetermined diameter is formed from the center of the holding member 45. The through-opening 44 penetrates the upper surface 45a of the holding member 45 and the lower surface 45b of the holding member 45 (that is, the surface facing the raw material). Through the through opening 44, the crystal growth surface 14a of the seed substrate 14 is exposed toward the raw material.

  The support 43 in such an embodiment also prevents the seed substrate 14 from moving in the direction along the crystal growth surface 14a. That is, the seed substrate 14 surrounded by the plurality of support bodies 43 formed on the upper surface 45a of the holding member 45 has a circumferential surface 14b in contact with the plurality of protrusions of the support body 43. Therefore, the seed substrate 14 extends along the crystal growth surface 14a. It is possible to reliably prevent movement in the direction. Thereby, the deterioration of the crystallinity of the grown crystal due to the movement of the seed substrate 14 can be prevented, and an aluminum nitride single crystal having good crystallinity can be produced.

  Further, the support body 43 can accurately position the placement position of the seed substrate 14 when placing the seed substrate 14 on the holding member 45. That is, the plurality of supports 43 are formed along a virtual circle R having a diameter that is the same as or slightly larger than the diameter of the seed substrate 14. It is possible to accurately and easily position and place the seed substrate 14 at the correct placement position of the seed substrate 14 in the holding member 45 simply by fitting into the holding member 45.

<Fifth Embodiment>
In the first embodiment described above, the raw material is heated in the crystal growth vessel to generate the sublimation gas, but a configuration in which the sublimation gas of the raw material is introduced from the outside of the crystal growth vessel is also preferable.
FIG. 6 is a schematic configuration diagram showing an aluminum nitride single crystal manufacturing apparatus according to a fifth embodiment.
The fourth embodiment is an apparatus for growing an aluminum nitride single crystal on a seed substrate by a vapor phase method such as a CVD method (chemical vapor deposition method).

  An aluminum nitride single crystal manufacturing apparatus 60 includes a crystal growth vessel 61 made of quartz or the like, a raw material gas supply unit 63 and a raw material gas supply port 63a for introducing a raw material gas provided at a lower portion of the crystal growth vessel 61, and a raw material gas. A susceptor (lid) 64 provided to face the supply unit 63, a holding member 15 provided below the susceptor 64, and a seed substrate 14 installed on the lower surface side of the susceptor 64 held by the holding member 15. And is configured. From the source gas supply unit 63 and the source gas supply port 63a, trimethylaluminum vapor, nitrogen, hydrogen, ammonia, or the like, which is a source gas of aluminum nitride, is introduced.

  A plurality of heating means 61 for heating the internal space of the crystal growth container 61 and the seed substrate 14 are provided along the outer periphery of the crystal growth container 61. The crystal growth vessel 61 and the heating means 69 are covered with a chamber 68. A gas inlet 65 such as nitrogen gas and a gas outlet 66 are provided on the ceiling of the chamber 68. Thereby, the inside of the chamber 60 can be adjusted to a predetermined gas pressure.

  Also in this embodiment, the support member 23 as shown in FIG. 2 is integrally formed with the holding member 15 that holds the seed substrate 14. The support 23 suppresses movement of the seed substrate 14 and facilitates positioning of the placement position of the seed substrate 14.

  In a conventional apparatus for producing an aluminum nitride single crystal by a vapor phase method, the seed substrate is generally fixed to the lower surface of the susceptor with an adhesive or the like. However, in the aluminum nitride single crystal manufacturing apparatus 60 according to this embodiment, the support 23 formed on the holding member 15 can hold the seed substrate 14 at a predetermined position while preventing the seed substrate 14 from moving or dropping off. Therefore, it is possible to reliably suppress the occurrence of growth defects of the aluminum nitride single crystal due to the movement or dropping of the seed substrate 14 from the susceptor. Therefore, an aluminum nitride single crystal having good crystallinity can be produced.

<Manufacturing method>
Next, an aluminum nitride single crystal manufacturing method using the aluminum nitride single crystal manufacturing apparatus shown in FIG. 1 will be described. When the aluminum nitride single crystal AlN is manufactured using the aluminum nitride single crystal manufacturing apparatus 10 of the present invention, first, a raw material 12 such as aluminum nitride powder is set on the inner bottom of the crystal growth vessel (crucible) 11. Next, the seed substrate 14 is placed on the holding member 15. At this time, the seed substrate 14 is simply fitted into the support 23 that is a circular groove with the crystal growth surface 14 a side of the seed substrate 14 facing down. Can be easily positioned at a predetermined position of the holding member 15.

  Thereafter, the inside of the crystal growth vessel 11 is put in a semi-sealed state. Next, a vacuum pump (not shown) is operated to remove the atmosphere inside the furnace body storage container 18 from the gas discharge port, and the pressure in the crystal growth container 11 is reduced. Subsequently, nitrogen gas is introduced into the crystal growth vessel 11. Thereby, the growth of the aluminum nitride single crystal is performed in a high purity nitrogen gas atmosphere.

  Then, the crystal growth vessel 11 is heated via the furnace body storage vessel 18 by heating means such as a heater. During the growth of the aluminum nitride single crystal, the temperature of the furnace body storage container 18 is constantly controlled at 1700 to 2300 ° C. During aluminum nitride single crystal growth, the temperature (raw material temperature) at the lower end of the furnace body storage container 18 is set to be higher than the temperature (crystal growth part temperature) above the furnace body storage container 18.

Crystal growth is started by depressurizing the crystal growth furnace 20 after heating to the above-mentioned set temperature, and is performed by maintaining a constant pressure of 100 to 600 torr.
During heating, the nitrogen gas in the crystal growth furnace 20 is discharged while the nitrogen gas is supplied into the crystal growth furnace 20 so that the nitrogen gas pressure and flow rate in the crystal growth furnace 20 are appropriately adjusted. adjust.

  The sublimation gas of the raw material 12 sublimated by vaporization by heating is deposited on the crystal growth surface 14a of the seed substrate 14 exposed at the through-opening of the holding member 15 in a nitrogen gas atmosphere, and is grown as a seed. It grows on the substrate 14 as aluminum nitride single crystal AlN.

  Even during the growth of such an aluminum nitride single crystal, the seed substrate 14 fitted in the circular groove forming the concave shape of the support 23 has a peripheral surface 14b that is in contact with the step 23a of the support 23. It is possible to reliably prevent movement in the direction along the surface 14a. Thereby, the deterioration of the crystallinity of the grown crystal due to the movement of the seed substrate 14 can be prevented, and an aluminum nitride single crystal having good crystallinity can be produced.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to a following example.
The aluminum nitride single crystal was grown on the seed substrate 14 with the aluminum nitride single crystal manufacturing apparatus 10 shown in FIG. As the seed substrate 14, a disk-shaped 6H—SiC single crystal (diameter 50 mm, thickness 600 μm) was used. The orientation and polarity of the growth surface were (0001) Si plane and (000-1) C plane. A 1 mm-thick disc-shaped member was used as the holding member 15, and a hole penetrating to the back surface of Φ30 mm was formed in the center portion to form a ring-shaped member.

Further, the holding member 15 in which the support 23 is integrally formed is made of tantalum carbide. After the crystal growth vessel 11 is installed in the apparatus, a dry pump and a turbo molecular pump (not shown) are sequentially operated to remove the atmosphere in the crystal growth furnace 20 and to increase the pressure in the crystal growth furnace 20 to 5. The pressure was reduced to × 10 ⁻⁶ torr. Thereafter, nitrogen gas was introduced into the apparatus and the pressure was increased to 700 torr.

  Next, after the temperature of the crystal growth vessel 11 was raised to about 2000 ° C., the pressure in the crystal growth furnace 20 was reduced to 100 to 600 torr to start aluminum nitride crystal growth. When 10 to 120 hours had elapsed from the start of growth, the pressure in the crystal growth furnace 20 was increased to 700 torr with nitrogen gas, and then the seed substrate 14 and the raw material temperature were cooled to room temperature, thereby terminating the crystal growth. The obtained aluminum nitride single crystal had a diameter of 30 mm, a thickness of 0.1 to 5 mm, and a growth rate of 10 to 120 μm / h.

  This crystal was cut into a 1 mm-thick plate in the vertical and horizontal directions with respect to the growth direction, and a sample for evaluation was produced. The sample for evaluation was polished to a mirror surface with a flat surface, and damage due to cutting was removed from the surface as much as possible. For evaluation, phase identification was analyzed from Raman scattering measurement, and crystallinity was analyzed by X-ray topography using an X-ray Lang camera. From the Raman scattering measurement, it was found that the obtained crystal phase was a (0001) AlN crystal having a 2H structure. Further, it was found from the X-ray topography image that the crystal defect density was lower by two orders of magnitude in the growth by the holding member as compared with the growth by the conventional adhesion holding of the seed substrate. These results indicate that holding the seed substrate using the holding member alleviated thermal strain in the (0001) in-plane direction and improved crystallinity.

  DESCRIPTION OF SYMBOLS 10 ... Manufacturing apparatus, 20 ... Crystal growth furnace, 11 ... Crystal growth container (crucible), 12 ... Raw material, 13 ... Lid, 14 ... Seed substrate, 15 ... Holding member, 23 ... Support, AlN ... Aluminum nitride single crystal.

Claims (9)

A crystal growth container; a seed substrate for growing an aluminum nitride single crystal; and a holding member that holds the seed substrate on one surface and has a through opening smaller than the outer diameter of the seed substrate in the center. ,
An apparatus for producing an aluminum nitride single crystal, comprising: a support body disposed along the periphery of the seed substrate so as to suppress movement of the seed substrate on the one surface of the holding member.   The said support body is the member A which makes concave shape from the said one surface of the said holding member, The manufacturing apparatus of the aluminum nitride single crystal of Claim 1 characterized by the above-mentioned.   The said member A is continuously arrange | positioned so that the periphery of the said seed substrate may be surrounded, The manufacturing apparatus of the aluminum nitride single crystal of Claim 2 characterized by the above-mentioned.   The apparatus for producing an aluminum nitride single crystal according to claim 2, wherein a plurality of the members A are intermittently provided so as to surround the periphery of the seed substrate.   The said support body is the member B which makes convex shape from the said one surface of the said holding member, The manufacturing apparatus of the aluminum nitride single crystal of Claim 1 characterized by the above-mentioned.   The said member B is continuously distribute | arranged so that the periphery of the said seed substrate may be surrounded, The manufacturing apparatus of the aluminum nitride single crystal of Claim 5 characterized by the above-mentioned.   6. The apparatus for producing an aluminum nitride single crystal according to claim 5, wherein a plurality of the members B are intermittently arranged so as to surround the periphery of the seed substrate.   The said holding member and the said support body are integral members, The manufacturing apparatus of the aluminum nitride single crystal of any one of Claim 1 thru | or 7 characterized by the above-mentioned. A method for producing an aluminum nitride single crystal by a sublimation method,
A crystal growth container; a seed substrate for growing an aluminum nitride single crystal on one surface; a holding member having a through opening smaller than the outer diameter of the seed substrate at a central portion; and holding the seed substrate on one surface; and the holding member A support body disposed along the periphery of the seed substrate so as to suppress the movement of the seed substrate,
A method for producing an aluminum nitride single crystal, wherein a sublimation gas containing aluminum nitride is deposited on the seed substrate while suppressing the movement of the seed substrate by the support.

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