JP5536501B2 - Silicon carbide single crystal manufacturing equipment - Google Patents

Description

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

  Conventionally, single-crystal wafers made of single crystals have been widely used as substrates for semiconductor devices such as next-generation LED devices, power devices, and high-frequency devices. As a method for producing this single crystal, a sublimation method is known. In this sublimation method, for example, a crucible provided with a lid, a crucible body, and a guide member (sealing part) is used (for example, see Patent Document 1). ).

JP 2004-352590 A

  However, the crucible described in Patent Document 1 has the following problems. That is, since the induction heating coil is not wound around the central portion and the lower portion of the guide member, the central portion and the lower portion of the guide member are likely to become low temperature. In this case, the sublimation gas generated from the sublimation raw material is deposited on the inner surface of the central part and the lower part of the guide member, which is lower in temperature than the other parts of the crucible, to form a polycrystal, thus preventing the growth of the single crystal There was a problem of being.

  Accordingly, an object of the present invention is to provide an apparatus for producing a silicon carbide single crystal capable of efficiently growing a single crystal from a seed crystal by reducing a portion of the guide member that has a low temperature.

  In order to solve the above-described problems, the present invention has the following features. The first feature of the present invention is that a crucible body (crucible body 5) containing a sublimation raw material (sublimation raw material 15) and a lid for attaching a seed crystal (seed crystal 23) at a position facing the sublimation raw material. A crucible (crucible 9) having a body (lid 3), a guide member (guide member 7) extending in a cylindrical shape from the lid toward the sublimation raw material, and heating means disposed on the outer peripheral side of the crucible body (Heating unit 13), a silicon carbide single crystal manufacturing apparatus (silicon carbide single crystal manufacturing apparatus 1), wherein the height of the guide member is H1, and the height of the heating means and the guide member When the height dimension overlapping in the vertical direction is H2, H2 = (0.5 to 1.0) × H1.

  First, H2 = (0.5 to 1.0) × H1 means that the heating means is disposed on the outer periphery of more than half of the guide member. As a result, most of the guide member becomes high temperature, and it is possible to suppress the growth of polycrystals from the inner wall surface of the guide member. Therefore, a good quality single crystal can be reliably grown.

  The second feature of the present invention is summarized as H2> H3, where H3 is a desired growth height for the single crystal (single crystal 39) grown from the seed crystal (seed crystal 23). . Here, the desired growth height is the height of the seed crystal after the growth is completed.

  According to the silicon carbide single crystal manufacturing apparatus according to the present invention, it is possible to efficiently grow a single crystal from a seed crystal by reducing a portion of the guide member that has a low temperature.

It is sectional drawing which shows the manufacturing apparatus of the silicon carbide single crystal which concerns on embodiment of this invention. It is sectional drawing which shows the manufacturing apparatus of the silicon carbide single crystal which concerns on a comparative example.

  Hereinafter, details of an apparatus for producing a silicon carbide single crystal according to an embodiment of the present invention will be described with reference to the drawings. Specifically, (1) the entire configuration of the silicon carbide single crystal manufacturing apparatus, (2) the entire configuration of the silicon carbide single crystal manufacturing apparatus according to the comparative example, (3) operational effects, (4) other embodiments Will be described. It should be noted that the drawings are schematic, and the thicknesses and ratios of the material layers are different from actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Also included in the drawings are portions having different dimensional relationships and ratios.

(1) Overall Configuration of Silicon Carbide Single Crystal Manufacturing Device First, the overall configuration of the silicon carbide single crystal manufacturing device 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a silicon carbide single crystal manufacturing apparatus 1 according to a first embodiment of the present invention.

  The manufacturing apparatus 1 includes a crucible 9 having a lid 3, a crucible body 5, and a guide member 7, a quartz tube 11 covering the outer periphery of the crucible 9, and a heating unit wound around the outer periphery of the quartz tube 11. 13.

  The crucible body 5 is opened at the upper end, and the opening is closed by the lid 3 and is made of graphite. A sublimation raw material 15 made of silicon carbide powder is accommodated at the bottom and supported by a support rod 17 attached to the lower part. When the sublimation raw material 15 is heated, a sublimation gas G is generated and guided to the seed crystal 23 by the guide member 7.

  The lid 3 is screwed into a threaded portion at the upper end of the crucible body 5 so as to seal the opening at the upper end of the crucible body 5, and is made of graphite. A disc-shaped pedestal 21 (seed crystal attachment portion) that protrudes downward is formed at the center of the lower surface 19 of the lid 3. A disk-shaped seed crystal 23 made of silicon carbide is attached to the lower surface of the pedestal 21.

  The heating unit 13 is spirally wound around the outer peripheral side of the quartz tube 11 and the entire crucible 9 covered with the quartz tube 11. The heating unit 13 is disposed between the upper induction heating coil 25 disposed on the upper side, the lower induction heating coil 27 disposed on the lower side, and the upper induction heating coil 25 and the lower induction heating coil 27. And an interference preventing coil 29.

The upper induction heating coil 25 is arranged corresponding to the height positions of the lid 3, the base 21 and the guide member 7, and the lower induction heating coil 27 corresponds to the height position of the sublimation raw material 15. Are arranged. In addition, the upper induction heating coil 25 is wound four times in the present embodiment, and is referred to as a first coil 31, a second coil 33, a third coil 35, and a fourth coil 37 from the upper side. As shown in FIG. 1, the first coil 31 is disposed at the height position of the lid 3, the second coil 33 corresponds to the height position of the upper end portion of the guide member 7, and the third coil 35 is a single crystal 39. The fourth coil 37 corresponds to the height position of the lower portion of the guide member 7.

  Here, the guide member 7 includes a cylindrical upper end portion 43 extending downward from the upper end 41 located on the lower surface 19 of the lid 3, and a cylindrical main body portion 45 whose diameter is increased obliquely downward from the lower end of the upper end portion 43. It consists of and. The height H1 from the upper end 41 of the upper end portion 43 to the lower end 47 of the main body portion 45 is the height H1 of the guide member 7. The lower end 47 of the guide member 7 is locked to a step formed at the boundary between the upper inner wall surface 51 and the lower inner wall surface 53 of the crucible body 5.

  On the other hand, the height dimension overlapping in the height direction between the guide member 7 and the upper induction heating coil 25 is H2. This H2 coincides with the vertical distance from the upper end of the second coil 33 to the lower end of the fourth coil 37. Further, assuming that the desired growth height of the single crystal 39 is H3, a magnitude relationship of H2 = (0.5 to 1.0) × H1 and H2> H3 is established between these H1, H2, and H3. To do. Here, the desired growth height indicates the height of the seed crystal after completion of the growth, and is determined by the size of the product.

  H2 = (0.5 to 1.0) × H1 means that the upper induction heating coil 25 is arranged on the outer periphery of a half or more portion of the guide member 7. Note that H2 = (0.8 to 1.0) × H1 is preferable. Further, H2> H3 means that the upper induction heating coil 25 is arranged on the outer periphery of all the height-wise portions of the grown single crystal 39.

(2) Overall Configuration of Silicon Carbide Single Crystal Manufacturing Apparatus 101 According to Comparative Example Next, the overall configuration of the silicon carbide single crystal manufacturing apparatus 101 according to the comparative example will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a silicon carbide single crystal manufacturing apparatus 101 according to a comparative example. Parts having the same configurations as those in FIG.

  In this comparative example, the height of the guide member 107 (vertical distance from the upper end 141 to the lower end 147) is h1, and overlaps in the height direction between the guide member 107 and the upper induction heating coil 125 (heating means 113). The size is h2. If the desired growth height of the single crystal 39 is h3, h2 is less than 0.5 times h1, and h3 is smaller than h2.

  Accordingly, since the upper induction heating coil 125 is not wound around the outer periphery of most of the guide member 107 except for the upper end portion, most of the guide member 107 is cooled to a polycrystalline 130 from the inner wall surface of the guide member 107. Will grow. Further, since h2 is smaller than the desired growth height h3, heating by the upper induction heating coil 125 is weakened from the middle of the growth of the single crystal 139, and a high-quality single crystal cannot be obtained.

(3) Action / Effect The silicon carbide single crystal manufacturing apparatus 1 according to the embodiment includes a crucible body 5 that houses a sublimation raw material 15, and a lid that attaches a seed crystal 23 to a position facing the sublimation raw material 15. 3, a guide member 7 extending in a cylindrical shape from the lid 3 toward the sublimation raw material 15, and a heating unit 13 disposed on the outer peripheral side of the crucible body 5. In the crystal manufacturing apparatus 1, when the height of the guide member 7 is H1, and the height dimension overlapping in the height direction of the heating unit 13 and the guide member 7 is H2, H2 = (0 0.5-1.0) × H1.

  First, H2 = (0.5 to 1.0) × H1 means that the upper induction heating coil 25 that is the heating unit 13 is disposed on the outer periphery of a portion that is half or more of the guide member 7. Thereby, most of the guide member 7 becomes a high temperature, and it is possible to suppress the growth of the polycrystal 130 from the inner wall surface of the guide member 7. Therefore, the high-quality single crystal 39 can be reliably grown.

  Further, when the desired growth height of the single crystal 39 grown from the seed crystal 23 is H3, H2> H3. H2> H3 means that the upper induction heating coil 25 serving as the heating unit 13 is arranged on the outer periphery of all the height-wise portions of the grown single crystal 39. Therefore, the heating by the heating unit 13 is not weakened from the time point during the growth of the single crystal 39, and the high-quality single crystal 39 can be obtained.

(4) Other Embodiments It should not be understood that the descriptions and drawings constituting a part of the disclosure of the above-described embodiments limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In this embodiment, although the case where the base 21 which protrudes below was provided in the back surface of the cover body 3 was demonstrated, it is not limited to this, The back surface itself (surface shape which does not protrude below) of the cover body 3 is used. The present invention is also applicable when used as a pedestal.

  As described above, the present invention naturally includes various embodiments that are not described herein. 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 ... Manufacturing apparatus of a silicon carbide single crystal, 3 ... Cover, 5 ... Crucible body, 7 ... Guide member, 9 ... Crucible, 13 ... Heating means, 15 ... Sublimation raw material, 23 ... Seed crystal, 25 ... Upper induction heating Coil (heating means), 39 ... single crystal

Claims (1)

A crucible body containing a sublimation raw material, a crucible having a lid on which a pedestal for attaching a seed crystal is formed at a position facing the sublimation raw material, and a cylinder extending from the lid toward the sublimation raw material An apparatus for producing a silicon carbide single crystal comprising a guide member and heating means disposed on the outer peripheral side of the crucible body,
The heating means includes an upper induction heating coil disposed on the upper side, a lower induction heating coil disposed on the lower side, and an interference preventing coil disposed between the upper induction heating coil and the lower induction heating coil. And consists of
The upper induction heating coil is disposed corresponding to the height position of the lid, the pedestal, and the guide member,
When the height of the guide member is H1 and the height dimension overlapping in the height direction of the upper dielectric heating coil and the guide member is H2, H2 = ( 0.8 to 1.0) × H1 Yes,
The lower induction heating coil and the interference prevention coil are in positions that do not overlap with the guide member in the height direction ,
An apparatus for producing a silicon carbide single crystal , wherein H2> H3, where H3 is a desired growth height of the single crystal grown from the seed crystal .

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