JP2011051824A - Single crystal producing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single crystal producing apparatus promoting growth in a radial direction of a single crystal when a silicon carbide single crystal is produced by using a sublimation method. <P>SOLUTION: The single crystal producing apparatus 1 includes a cylindrical crucible 50 having: a reaction container 30 housing a seed crystal 10 having a prescribed crystal orientation and a raw material 20 for sublimation; and a lid part 40. A first guide member 61, a second guide member 62 and a third guide member 63 are provided between the seed crystal 10 and the raw material 20 for sublimation. The first guide member 61 has a regulating surface 61a regulating a growth range of the single crystal growing on the seed crystal 10. The second guide member 62 is provided in a position nearer to the raw material 20 for sublimation than the first guide member 61 and guides a raw material gas toward an inner wall 31 of the reaction container 30. The third guide member 63 is disposed between the first and second guide members 61 and 62 and has a guiding surface 63a opposed to the regulating surface 61a of the first guide member 61. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a single crystal manufacturing apparatus used for manufacturing a single crystal ingot which is a material of a semiconductor wafer.

  One method for producing a single crystal such as silicon carbide is a sublimation method. In the sublimation method, a raw material material that is a raw material for a single crystal is heated and recrystallized on a seed crystal as a raw material gas. In the sublimation method, a single crystal is likely to grow in a direction perpendicular to the surface of the seed crystal and is difficult to grow in a diameter direction along the surface of the seed crystal.

  Therefore, in the sublimation method, a method for promoting the growth of a single crystal in the radial direction of the seed crystal has been proposed (see, for example, Patent Document 1). In the method disclosed in Patent Document 1, the source material is preferentially supplied to the periphery of the seed crystal by disposing the source material on the inner wall portion side outside the central portion of the bottom surface of the substantially cylindrical crucible. Yes.

  Further, a method is disclosed in which a source member gas is efficiently supplied onto the surface of the seed crystal by providing a guide member that guides the sublimation gas sublimated from the source material to the surface of the seed crystal (see Patent Document 2).

Japanese Patent Laid-Open No. 11-268990 (FIG. 1) Japanese Patent Laid-Open No. 2002-60297 (page 8, FIG. 1)

  However, even if the above-described method is used, it is difficult to promote the growth of the seed crystal in the radial direction. In the method disclosed in Patent Document 1, the raw material is arranged and heated on the inner wall portion side outside the central portion of the bottom surface of the crucible. Since the raw material is a heat source, a temperature distribution is generated inside the crucible with the temperature being higher toward the outer side in the radial direction and lower at the center. On the other hand, the temperature distribution in the height direction of the crucible (thickness direction of the seed crystal) is smaller than the temperature distribution in the radial direction inside the crucible.

  Thus, even if the raw material is disposed on the inner wall side outside the center of the bottom surface of the crucible, it tends to be recrystallized in the central part where the temperature is lower than that of the surroundings. It was difficult to grow preferentially along.

  Accordingly, an object of the present invention is to provide a single crystal manufacturing apparatus for manufacturing a silicon carbide single crystal using a sublimation method, which can promote the growth of the single crystal in the radial direction. And

  In order to solve the above-described problems, the present invention has the following features. The first special feature of the present invention is a crucible (crucible 50, reaction) containing a seed crystal (seed crystal 10) used for growing a single crystal and a raw material (sublimation raw material 20) that is a raw material of the single crystal. A single crystal comprising a container 30) and a heating unit (dielectric heating coil 90) for heating the crucible, and producing a single crystal by a sublimation method in which a source gas obtained by sublimating the source material is recrystallized on the seed crystal. A manufacturing apparatus (single crystal manufacturing apparatus 1), which has a regulating surface (regulating surface 61a) that is disposed inside the crucible and regulates the growth range of the single crystal grown based on the seed crystal. A guide member (first guide member 61) and a second guide member (second guide member) that is disposed closer to the source material than the first guide member and guides the source gas toward the inner wall of the crucible. 62), the first guide member and the first And a third guide member (third guide member 63) having a guide surface (guide surface 63a) disposed between the guide member and facing the restriction surface of the first guide member. .

  According to the first feature of the present invention, the source gas sublimated from the source material is guided toward the inner wall of the crucible by the second guide portion, and then rises to the seed crystal side along the inner wall, so that the first guide The space between the member and the third guide member is moved toward the seed crystal. Since the region close to the seed crystal is restricted by the first guide member and the third guide member, the source gas is easily supplied to the outer edge portion of the seed crystal. For this reason, crystal growth in the radial direction of the seed crystal is promoted. Further, even during the growth of a single crystal, the source gas is likely to be supplied around the outer edge of the crystal growth surface. For this reason, crystal growth in the radial direction is promoted.

  The second feature of the present invention is related to the first feature of the present invention, wherein the inside of the crucible has a cylindrical shape, and the regulating surface and the guide surface are center axes passing through the center of the seed crystal ( The gist of the present invention is that it is a part of a conical surface having a virtual vertex on the central axis CL) and a bottom surface on the raw material side.

  A third feature of the present invention relates to the first feature of the present invention, wherein the inside of the crucible has a cylindrical shape, and the second guide member (second guide member 65) transfers the source gas to the source gas. The gist is to have a source gas guide surface (source gas guide surface 65a) leading toward the inner wall of the crucible, and the source gas guide surface is a plane parallel to the surface of the seed crystal.

  A fourth feature of the present invention relates to the first feature of the present invention, wherein the inside of the crucible has a cylindrical shape, and the second guide member guides the source gas toward the inner wall of the crucible. A source gas guide surface, the source gas guide surface being a part of a conical surface having a virtual vertex on a central axis passing through the center of the seed crystal and a bottom surface on the seed crystal side; Is the gist.

  A fifth feature of the present invention relates to the first feature of the present invention, wherein the seed crystal has a disc shape, and the seed crystal is located at a position corresponding to the seed crystal of the third guide member. The gist is that an opening (opening 63b) having a hole diameter at least as large as or larger than the diameter of is formed.

  A sixth feature of the present invention is related to the first feature of the present invention, and is characterized by having a connecting portion that connects the second guide member and the third guide member.

  A seventh feature of the present invention relates to the first feature of the present invention, and is summarized in that the third guide member is replaceable.

  According to the present invention, an object of the present invention is to provide an apparatus for producing a single crystal capable of promoting the growth of the single crystal in the radial direction when producing a silicon carbide single crystal using a sublimation method.

FIG. 1 is a cross-sectional view illustrating a single crystal manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view for explaining the positional relationship between the guide member and the sublimation raw material in the graphite crucible of the single crystal manufacturing apparatus according to the embodiment of the present invention. FIG. 3 is a plan view for explaining the shape of the guide member. FIG. 4 is a plan view illustrating another shape of the guide member. FIG. 5 is a flowchart for explaining a method for producing a single crystal according to an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a single crystal manufacturing apparatus according to another embodiment of the present invention. FIG. 7 is a cross-sectional view illustrating a single crystal manufacturing apparatus according to another embodiment of the present invention.

  Next, the single crystal manufacturing apparatus according to the present embodiment will be described with reference to the drawings. Specifically, (1) Schematic configuration of single crystal manufacturing apparatus, (2) Guide member configuration, (3) Silicon carbide single crystal manufacturing method, (4) Action / effect, (5) Other implementation of guide member Form, (6) Other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Schematic configuration of single crystal manufacturing apparatus The configuration of a single crystal manufacturing apparatus according to the present invention will be described with reference to FIG. In the present embodiment, the single crystal is a silicon carbide single crystal. FIG. 1 is a cross-sectional view showing a single crystal manufacturing apparatus 1 (a state before the growth of a single crystal) according to the present embodiment. The single crystal manufacturing apparatus 1 includes a reaction vessel 30 that contains a seed crystal 10 that is a single crystal having a predetermined crystal orientation, a sublimation raw material 20 that is used for growing the single crystal, and a lid that is detachable from the reaction vessel 30. A cylindrical graphite crucible (hereinafter referred to as a crucible 50) having a portion 40 is provided. The lid 40 is detachably provided on the reaction container 30 by screwing. Here, the sublimation raw material 20 constitutes a raw material.

  A seed crystal 10 is disposed on the inner surface 41 of the lid 40 at a position substantially opposite to the sublimation raw material 20. A first guide member 61, a second guide member 62, and a third guide member 63 are provided between the seed crystal 10 and the sublimation raw material 20. Details of the guide member will be described later.

  The crucible 50 is covered with a heat insulating material (not shown). Further, the crucible 50 is fixed inside the quartz tube 80 via a support rod 70. On the outer periphery of the quartz tube 80, a dielectric heating coil 90 for heating the crucible 50 (that is, the reaction vessel 30 and the lid 40) is provided.

  The inside of the reaction vessel 30 is filled with an inert gas such as argon to form an inert atmosphere. The pressure and temperature inside the reaction vessel 30 can be changed. The sublimation raw material 20 is a silicon carbide raw material containing silicon carbide. When the inside of the crucible 50 reaches predetermined temperature conditions and pressure conditions, the sublimation raw material 20 sublimates and recrystallizes on the seed crystal 10 to form a silicon carbide single crystal.

(2) Configuration of Guide Member Next, configurations of the first guide member 61, the second guide member 62, and the third guide member 63 will be described with reference to FIGS.

  The first guide member 61 is disposed inside the crucible 50 (that is, the reaction vessel 30) and has a regulating surface 61 a that regulates the growth range of the single crystal grown based on the seed crystal 10. The second guide member 62 is disposed closer to the sublimation raw material 20 than the first guide member 61, and guides the raw material gas toward the inner wall 31 of the reaction vessel 30 of the crucible 50. The third guide member 63 has a guide surface 63 a that is disposed between the first guide member 61 and the second guide member 62 and faces the restriction surface 61 a of the first guide member 61.

  The regulation surface 61 of the first guide member 61 and the guide surface 63a of the second guide member 62 each have virtual vertices on the central axis CL passing through the center of the seed crystal 10, and are bottom surfaces on the sublimation raw material 20 side. Part of a conical surface having

  The second guide member 62 has a source gas guide surface 62 a that guides the source gas toward the inner wall 31 of the reaction vessel 30. The source gas guide surface 62a is a part of a conical surface having a virtual vertex on the central axis CL passing through the center of the seed crystal 10 and a bottom surface on the seed crystal 10 side. In the present embodiment, the second guide member 62 and the third guide member 63 are connected by a connecting portion 64. Note that the third guide member 63 is replaceable.

  3 and 4 are plan views of the reaction vessel 30 viewed from the top of the seed crystal 10 along the central axis direction. For the sake of explanation, the lid 40, the seed crystal 10, and the first guide member are not shown in FIGS. As shown in FIG. 3, the second guide member 62 is attached to the inner wall 31 of the reaction vessel 30 by bridge portions 71, 72, 73. A gap 74 is formed between the reaction vessel 30 and the second guide member 62 other than the place where the bridge portions 71, 72, 73 are provided. Therefore, the raw material gas sublimated by the sublimation raw material 20 passes through the gap 74 and is guided between the first guide member 61 and the third guide member 63 to the seed crystal 10.

  Further, as shown in FIG. 4, the second guide member 62 may be attached by an attachment portion 80. An opening 81 is formed in the attachment portion 80. Therefore, the source gas sublimated by the sublimation source 20 passes through the opening 81 and is guided between the first guide member 61 and the third guide member 63 to the seed crystal 10. Thus, the first guide member 61 not only regulates the growth range of the growing single crystal but also functions as a guide that preferentially guides the source gas to the outer edge portion of the seed crystal 10.

  In addition, although the structure which attached the 2nd guide member 62 to the reaction container 30 was demonstrated using FIG. 3, FIG. 4, you may attach the 3rd guide member 63 to the reaction container 30 with the same method. In the present embodiment, since the second guide member 62 and the third guide member 63 are connected by the connecting portion 64, either one is attached to the reaction vessel 30.

(3) Manufacturing method of silicon carbide single crystal The manufacturing method of the silicon carbide single crystal which concerns on this embodiment is demonstrated with reference to FIG. FIG. 5 is a diagram for explaining a method for producing a silicon carbide single crystal. The method for manufacturing a silicon carbide single crystal includes steps S1 to S6.

  Step S1 is a step of preparing the above-described sublimation raw material. Step S <b> 2 is a step of arranging the sublimation raw material 20, the seed crystal 10, and the guide members 61, 62, 63 in the single crystal manufacturing apparatus 1. Step S3 is a step of heating the crucible 50 (reaction vessel 30 and lid 40) to sublimate the sublimation raw material 20. In step S <b> 4, the source gas obtained by sublimating the sublimation source material 20 by heating is guided to the inner wall 31 of the reaction vessel 30 along the source gas guide surface 62 a of the guide member 62. The source gas passes between the connecting portion 64 and the inner wall 31, travels between the first guide member 61 and the third guide member 63, and is guided to the seed crystal 10. Silicon carbide sublimated from the sublimation raw material 20 reaches the outer edge of the seed crystal 10 preferentially and recrystallizes at the outer edge.

  The source gas moves toward the seed crystal 10 in the space between the first guide member 61 and the third guide member 63. By providing the above-described guide member, the source gas is easily supplied to the outer edge portion of the seed crystal 10. Thereby, crystal growth in the radial direction of the seed crystal 10 is promoted.

  Subsequent to step S4, the outer peripheral surface of the silicon carbide single crystal is ground in step S5, and further, in step S6, the semiconductor wafer is cut out from the ingot manufactured in step S5 by slicing.

(4) Action / Effect According to the single crystal manufacturing apparatus 1, after the source gas sublimated from the sublimation raw material 20 is guided toward the inner wall 31 of the crucible 50 (reaction vessel 30) by the second guide member 62, Ascending toward the seed crystal 10 along the inner wall 31, the space between the first guide member 61 and the third guide member 63 moves toward the seed crystal 10. Since the region close to the seed crystal 10 is regulated by the first guide member 61 and the third guide member 63, the source gas is easily supplied preferentially to the outer edge portion of the seed crystal 10.

  For this reason, crystal growth in the radial direction of the seed crystal 10 is promoted. Further, even during the growth of a single crystal, the source gas is likely to be preferentially supplied to the outer edge portion of the crystal growth surface. For this reason, crystal growth in the radial direction of the crystal growth surface is promoted during crystal growth.

  In the single crystal manufacturing apparatus 1, the regulation surface 61 a of the first guide member 61 and the guide surface 63 a of the third guide member 63 are part of a conical surface. Can lead to efficient. Therefore, crystal growth in the radial direction of the crystal growth surface is promoted.

  The second guide member 62 has a source gas guide surface 62a that is a conical surface with the bottom surface on the seed crystal 10 side. For this reason, it is easy to guide the source gas evenly to the inner wall 31 side of the reaction vessel 30.

(5) Another Embodiment of Single Crystal Manufacturing Apparatus In the embodiment described above, the second guide member 62 is a conical surface that gradually expands from the sublimation raw material 20 toward the seed crystal 10 side. However, you may change as follows. The same parts as those of the single crystal manufacturing apparatus 1 according to the embodiment described above are denoted by the same reference numerals, and only different parts will be described.

  In the single crystal manufacturing apparatus 2, the second guide member 65 including the second guide member 65 has a source gas guide surface 65 a that guides the source gas toward the inner wall 31 of the reaction vessel 30. The source gas guide surface 65 a is a plane parallel to the surface of the seed crystal 10.

  In the single crystal manufacturing apparatus 3, an opening 63 b having a hole diameter at least equal to or larger than the diameter of the seed crystal 10 is formed at a position facing the seed crystal 10 of the third guide member 63. In the single crystal manufacturing apparatus 3, the source gas flowing between the regulation surface 61 a of the first guide member 61 and the guide surface 63 a of the third guide member 63 passes through the opening 63 b formed in the third guide member 63 and moves downward. Therefore, the flow of the source gas around the seed crystal 10 becomes smooth and recrystallization is promoted. In any of the single crystal manufacturing apparatuses 1, 2, and 3, the connecting portion 64 is not necessarily provided.

(6) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. should not do.

  The crystal polymorphism, amount used, purity, production method, etc. of the sublimation raw material 20 can be selected as appropriate. Moreover, there is no restriction | limiting in particular as a material of the crucible 50 and the guide member 60, According to the objective (a sublimation raw material and the kind of seed crystal), it can select suitably. In particular, the crucible 50 and the guide member 60 are preferably formed of a material excellent in durability, heat resistance, heat transfer, and the like, and in addition to these, there is less mixture of polycrystals and polymorphs due to generation of impurities. From the viewpoint of easy control of sublimation and recrystallization of the sublimation raw material, it is preferably made of graphite.

  In the present embodiment, the second guide member 62 and the third guide member 63 are connected by the connecting portion 64, but the second guide member 62 and the third guide member 63 may not be connected. It is preferable to combine the case where the second guide member 62 and the third guide member 63 are not coupled with the opening 63 b of the third guide member 63.

  From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 1 ... Single crystal manufacturing apparatus, 10 ... Seed crystal, 20 ... Raw material for sublimation, 30 ... Reaction container, 40 ... Lid part, 41 ... Bottom part, 50 ... Crucible, 61 ... First guide member, 61a ... Restriction surface, 62 ... 2nd guide member, 62a ... Raw material gas guide surface, 63 ... 3rd guide member, 63a ... Guide surface, 63b ... Opening part, 64 ... Connection part, 65 ... 3rd guide member, 70 ... Support rod, 80 ... Quartz tube , 90 ... induction heating coil

Claims (7)

A seed crystal used for growing a single crystal; a crucible containing a raw material that is a raw material of the single crystal; and a heating unit that heats the crucible, and the raw material gas obtained by sublimating the raw material is the seed A single crystal manufacturing apparatus for manufacturing a single crystal by a sublimation method for recrystallization on a crystal,
A first guide member that is disposed inside the crucible and has a regulating surface that regulates a growth range of the single crystal grown based on the seed crystal;
A second guide member that is disposed closer to the source material than the first guide member and guides the source gas toward the inner wall of the crucible;
A single crystal manufacturing apparatus comprising: a third guide member disposed between the first guide member and the second guide member and having a guide surface facing the restriction surface of the first guide member. The inside of the crucible has a cylindrical shape,
2. The control surface according to claim 1, wherein the restriction surface and the guide surface are part of a conical surface having a virtual vertex on a central axis passing through the center of the seed crystal and a bottom surface on the source material side. Single crystal manufacturing equipment. The inside of the crucible has a cylindrical shape,
The second guide member has a source gas guide surface that guides the source gas toward the inner wall of the crucible,
The single crystal manufacturing apparatus according to claim 1, wherein the source gas guide surface is a plane parallel to the surface of the seed crystal. The inside of the crucible has a cylindrical shape,
The second guide member has a source gas guide surface that guides the source gas toward the inner wall of the crucible,
2. The single crystal production according to claim 1, wherein the source gas guide surface is a part of a conical surface having a virtual apex on a central axis passing through a center of the seed crystal and having a bottom surface on the seed crystal side. apparatus. The seed crystal has a disc shape,
The single crystal manufacturing apparatus according to claim 1, wherein an opening having a hole diameter at least equal to or larger than the diameter of the seed crystal is formed at a position corresponding to the seed crystal of the third guide member.   The single crystal manufacturing apparatus according to claim 1, further comprising a connecting portion that connects the second guide member and the third guide member.   The single crystal manufacturing apparatus according to claim 1, wherein the third guide member is replaceable.

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