JP2017065969A - Graphite crucible for producing silicon carbide single crystal ingot and method for producing silicon carbide single crystal ingot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a graphite crucible for producing a silicon carbide single crystal ingot which can efficiently sublimate a silicon carbide raw material charged into the crucible during the growth of a silicon carbide single crystal and is suitable for producing a large diameter and long silicon carbide single crystal ingot, and to provide a method for producing a silicon carbide single crystal ingot using the graphite crucible.SOLUTION: In a graphite crucible 1 for producing a silicon carbide single crystal ingot 4, a crucible body 1a and a crucible upper lid 1b are provided, a silicon carbide raw material 3 is filled into a raw material filled portion 1c of a crucible body 1a lower part and a seed crystal 2 is disposed on the inner surface of the crucible upper lid 1b, and the silicon carbide single crystal ingot 4 is produced by a sublimation recrystallization method where the silicon carbide raw material 3 is heated and sublimated and the sublimated gas is recrystallized on the surface of the seed crystal 2. In the raw material filled portion 1c, a disk-like graphite partition wall 20 is provided whose peripheral base portion is fixed to the inner surface of the side wall of the raw material filled portion 1c and which has a partition wall opening portion 21 substantially at the center thereof. A method for producing a silicon carbide single crystal ingot uses the graphite crucible 1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a graphite crucible for producing a silicon carbide single crystal ingot used for producing a silicon carbide single crystal ingot by growing a silicon carbide single crystal by a sublimation recrystallization method using a seed crystal, and this graphite crucible. The present invention relates to a method for manufacturing a silicon carbide single crystal ingot, which is used to manufacture a silicon carbide single crystal ingot.

A silicon carbide single crystal having high thermal conductivity and a large band gap is a useful material as a substrate for electronic materials used at high temperatures and electronic materials that require high breakdown voltage.
As one method for producing such a silicon carbide single crystal, a sublimation recrystallization method (Rayleigh method) is known. In this sublimation recrystallization method, a silicon carbide single crystal is produced by sublimating a raw material silicon carbide powder at a high temperature exceeding 2000 ° C. and recrystallizing the generated sublimation gas (raw material gas) to a low temperature part. It is. Further, in this Rayleigh method, a method of producing a silicon carbide single crystal using a seed crystal composed of a silicon carbide single crystal is called an improved Rayleigh method (Non-patent Document 1), and is a bulk silicon carbide single crystal ingot. It is used for manufacturing.

  In this improved Rayleigh method, since a seed crystal is used, the nucleation process of the crystal can be optimized, and by adjusting the atmospheric pressure by an inert gas to about 10 Pa to 15 kPa, a silicon carbide single crystal The reproducibility of the growth rate and the like can be improved. For this reason, generally, an appropriate temperature difference is provided between the raw material and the seed crystal, and a silicon carbide single crystal is grown on the seed crystal. Further, the obtained silicon carbide single crystal (silicon carbide single crystal ingot) is used after being subjected to processing such as grinding, cutting, and polishing in order to obtain a standard shape as a substrate of an electronic material.

Here, the principle of the improved Rayleigh method will be described with reference to FIG.
As the silicon carbide raw material 3 used in the sublimation recrystallization method, a silicon carbide crystal powder [usually, a silicon carbide crystal powder produced by the Acheson method is washed and pretreated is used. As the graphite crucible 1, a crucible provided with a cylindrical crucible main body 1a having an upper end opening and a crucible upper lid 1b for closing the upper end opening of the crucible main body 1a is used. The silicon carbide raw material 3 is loaded into the raw material filling portion 1c below the crucible body 1a, and a seed crystal 2 made of a silicon carbide single crystal is placed on the inner surface of the crucible upper lid 1b. In the crucible 1, the silicon carbide raw material 3 is heated to 2400 ° C. or higher in an inert gas atmosphere such as argon (10 Pa to 15 kPa). During this heating, a temperature gradient is set in the crucible 1 so that the temperature of the seed crystal 2 side is slightly lower than that of the silicon carbide raw material 3 side, and the silicon sublimation gas sublimated from the silicon carbide raw material 3 is heated and sublimated. Is diffused and transported in the direction of the seed crystal 2 by the flow caused by the temperature gradient and the flow caused by the concentration gradient (formed by the temperature gradient), recrystallized on the surface of the seed crystal 2, and crystal growth proceeds. Thus, a single crystal ingot 4 is formed. In addition, the code | symbol 5 is a heat insulating material in FIG.

  By the way, the diameter of the silicon carbide single crystal substrate is required to be increased in order to reduce the manufacturing cost as much as possible when used as a substrate for manufacturing an electronic device. For this reason, with respect to the ingot for manufacturing a silicon carbide single crystal substrate, it is possible to manufacture a large number of substrates from one ingot at the same time as increasing its diameter, and during cutting and grinding. In order to further increase the productivity, it is also required to lengthen the ingot obtained by crystal growth.

  However, in the improved Rayleigh method, since the crystal growth is performed by the method as described above, it is difficult to add the silicon carbide raw material during the crystal growth. Therefore, in order to produce a large-diameter and long-sized silicon carbide single crystal ingot, it is necessary to load a larger amount of silicon carbide raw material in the crucible raw material filling portion than in the case of crystal growth of a small-diameter ingot. The diameter and depth of the raw material filling portion need to be increased, but in order to effectively use the silicon carbide raw material loaded in such a large amount for crystal growth, the entire silicon carbide raw material in the raw material filling portion It is indispensable to efficiently heat and sublimate to sublimation temperature.

  And, as a method of heating the silicon carbide raw material in the crucible, generally, the graphite crucible is heated using high frequency induction heating, the silicon carbide raw material is heated through the heated crucible, and the above described crucible is put in the crucible. A temperature gradient is formed. In addition, in such high frequency induction heating, since the generation of the induced high frequency current depends on the penetration depth of the high frequency, a heat generation distribution determined by the shape of the crucible is generated, and is strong near the outer peripheral surface of the crucible side wall. Heat generation occurs, and this heat is transmitted to the silicon carbide raw material in the raw material filling portion by heat conduction or heat radiation, whereby the silicon carbide raw material is heated. Focusing on the silicon carbide raw material charged in the raw material filling portion of the crucible, if the crucible is cylindrical and the silicon carbide raw material is loaded in the cylindrical shape in the raw material filling portion, the cylindrical carbonization is induced by induction heating. Since the side surface of the silicon raw material is strongly heated, the vicinity of the outer peripheral portion of the silicon carbide raw material (the outer peripheral portion of the raw material filling portion of the crucible) is more easily heated, and the central axis of the silicon carbide raw material (the central axis of the raw material filling portion of the crucible) ) There is a tendency that the heating temperature for the silicon carbide raw material is higher than that in the vicinity, and the heating temperature for the silicon carbide raw material decreases from the outer peripheral portion of the silicon carbide raw material toward the central axis.

  When the raw material filling part is heated in this way, sublimation gas is generated from the high temperature part of the silicon carbide raw material in the raw material filling part and crystal growth occurs on the seed crystal, but the temperature in the raw material in the raw material filling part is unavoidable. Distribution occurs, and the raw material near the central axis of the raw material filling portion becomes a low temperature portion. And in order to raise the temperature of this low temperature part to the sublimation temperature and sublimate the raw material near the central axis that becomes the low temperature part, the current value of the induced current is increased and the temperature of the side wall part of the graphite crucible is made higher. There is a need to. On the other hand, when the temperature of the side wall portion of the crucible is increased, the temperature of the entire crucible is increased, the temperature of the seed crystal and the growing single crystal is also increased, and the temperature gradient between the seed crystal and the raw material is reduced. The driving force of crystal growth based on the gradient is reduced, and there is a problem of crystal growth stop that stops crystal growth in the middle.

  Therefore, some proposals have been made in the past regarding methods for heating the raw material filling portion. For example, in order to prevent the temperature of the bottom wall portion (crucible bottom wall portion) of the raw material filling portion of the crucible from decreasing, Disclosed is a method of efficiently heating a raw material by disposing a heat insulating material in the portion to suppress recrystallization in the lower portion of the raw material filling portion (Patent Document 1). Moreover, the method of making the temperature distribution inside a raw material uniform by devising the shape of the side wall of the crucible of a raw material filling part is disclosed (patent document 2).

And the method of arrange | positioning an induction heating coil under the crucible bottom wall part is disclosed as a method of directly heating the bottom wall part (crucible bottom wall part) of the raw material filling part of a crucible (patent document 3). In addition, by making the electric conductivity of the bottom wall part (crucible bottom wall part) of the raw material filling part of the crucible higher than the side wall part, increasing the heat generation of the crucible bottom wall part and raising the temperature of the crucible bottom wall part A method of heating up to the crucible bottom wall is disclosed (Patent Document 4).
Furthermore, a method of providing a raw material gas rectifying guide at the upper part of the raw material filling part in order to control the flow of gas toward the seed crystal is disclosed (Patent Document 5).

JP 2010-76,990 JP 2007-230,846 JP 2013-216,549 JP 2010-206,876 Japanese Patent No. 5,397,503

Yu. M. Tairov and V. F. Tsvetkov, Journal of Crystal Growth, 52 (1981) pp.146

  However, in the method of Patent Document 1, since the heat generating part is the side wall part of the crucible, the problem that the temperature in the vicinity of the central axis of the raw material filling part is lower than the temperature of the outer peripheral part still remains, Therefore, when the diameter of the crucible is increased, this method is difficult to adopt for the purpose of efficiently heating the raw material in the vicinity of the central axis of the raw material filling portion. In the method of Patent Document 2, the heat generation distribution in the vicinity of the crystal part growing on the seed crystal also changes as the heat generation distribution on the crucible sidewall changes, and the crystal growth follows an isotherm. Since the growth surface shape of the crystal that grows with the change in the heat generation distribution is also affected, it is necessary to achieve both optimization of the temperature of the crystal growth part of the raw material filling part, It is very difficult to achieve both soaking and optimization.

  Further, in the method of Patent Document 3, the lower part of the crucible can be directly heated. However, since the structure of the apparatus is complicated, the side induction heating coil and the lower induction heating coil interact with each other. It is very difficult to optimize the current flowing through the induction heating coil. Furthermore, in the method of Patent Document 4, since the heat generation near the crucible side wall is increased, there still remains a problem that the temperature of the outer peripheral portion of the raw material filling portion becomes high, and the outer peripheral portion of the raw material filling portion and the raw material A temperature difference inevitably occurs between the vicinity of the central axis of the filling portion, and it is difficult to efficiently sublimate the raw material near the central axis of the raw material filling portion.

  Furthermore, in the method of Patent Document 5, the flow of the sublimation gas from the upper surface position of the silicon carbide raw material initially loaded in the raw material filling portion to the seed crystal can be controlled. The flow of the sublimation gas cannot be controlled inside, and it is difficult to heat the raw material near the central axis of the raw material filling part. In order to increase the temperature near the central axis of the raw material filling part, the temperature of the entire crucible It is necessary to raise. When the temperature of the entire crucible is raised, the recrystallized silicon carbide may sublimate again due to the high temperature of the crystal growth part of the seed crystal, resulting in defects in that part, and obtaining a high-quality single crystal. There is a problem that can not be. For this reason, also in the method of Patent Document 5, it is difficult to effectively heat the silicon carbide raw material in the vicinity of the central axis of the raw material filling portion, and it is necessary to increase the diameter and length of the ingot that requires a large amount of sublimation gas. Is unsuitable.

  The present invention provides a silicon carbide single crystal suitable for producing a large-diameter and long silicon carbide single crystal ingot by efficiently sublimating a silicon carbide raw material loaded in a raw material filling portion of a crucible during the growth of a silicon carbide single crystal. It aims at providing the manufacturing method of a crystal ingot.

  The present inventors can efficiently sublimate the silicon carbide raw material loaded in the raw material filling portion of the graphite crucible when producing a large-diameter and long silicon carbide single crystal ingot using high-frequency induction heating. The method was studied earnestly. As a result, the high-temperature sublimation gas generated by being heated to a high temperature is used as a heat source, that is, a partition wall having a partition opening portion at a substantially central portion is disposed inside the raw material filling portion, and carbonization in the raw material filling portion is performed. The flow of the sublimation gas flowing in the silicon raw material is controlled, and the flow of this high temperature sublimation gas is forcibly guided to the relatively low temperature silicon carbide raw material portion in the raw material filling portion. A method for heating a relatively low temperature silicon carbide raw material located near the central axis has been reached. According to this method, it is possible to sublimate the raw material in the vicinity of the central axis of the raw material filling portion of the crucible, which has been difficult to be heated, and efficiently sublimate the silicon carbide raw material loaded in the crucible, thereby increasing the diameter and length of the material. The present inventors have found that a silicon carbide single crystal ingot can be produced.

That is, the gist of the present invention is as follows.
[1] A crucible body made of graphite formed in a cylindrical shape with an upper end opening and a crucible upper lid for closing the upper end opening of the crucible body, and a raw material filling portion for filling a silicon carbide raw material at the lower part of the crucible body The silicon carbide raw material charged in the raw material filling portion is heated and sublimated, and the generated sublimation gas is recrystallized on the surface of a seed crystal made of a silicon carbide single crystal installed on the inner surface of the crucible upper lid In a graphite crucible for producing a silicon carbide single crystal by a sublimation recrystallization method,
In the raw material filling part at the lower part of the crucible body, a peripheral base is fixed to the inner surface of the side wall of the raw material filling part, and a disk-shaped graphite partition wall having a partition opening is provided at a substantially central part. A graphite crucible for producing a silicon carbide single crystal ingot.
[2] The opening area of the partition wall opening portion of the graphite partition wall is 0.1 to 0.5 times the area of the upper surface of the initial silicon carbide raw material charged in the raw material filling portion. A graphite crucible for producing a silicon carbide single crystal ingot according to [1].
[3] A graphite crucible main body formed in a cylindrical shape with an upper end opening, and a crucible upper lid for closing the upper end opening of the crucible main body, and a raw material filling portion for filling a silicon carbide raw material at the lower part of the crucible main body A graphite crucible having a graphite crucible, a silicon carbide raw material is loaded into a raw material filling portion at a lower portion of the crucible body of the graphite crucible, a seed crystal made of a silicon carbide single crystal is placed on the inner surface of the crucible upper lid, and a side surface of the crucible body In a method for producing a silicon carbide single crystal by generating a sublimation gas by high-frequency induction heating and recrystallizing the generated sublimation gas on the seed crystal,
The raw material filling portion at the lower part of the crucible body is provided with a disk-shaped graphite partition wall having a peripheral base fixed to the inner wall surface of the crucible body and having a partition wall opening at a substantially central portion. A silicon carbide single crystal ingot characterized by guiding the generated sublimation gas in a direction toward the central axis of the raw material filling portion and heating the silicon carbide raw material located around the central axis in the raw material filling portion to a sublimation temperature. Production method.

  According to the graphite crucible for producing a silicon carbide single crystal ingot of the present invention, when growing a large-diameter and long silicon carbide single crystal ingot using the graphite crucible, the carbonization charged in the raw material filling portion of the crucible is performed. With respect to the silicon raw material, the temperature in the vicinity of the central axis of the raw material filling portion can be made as high as the temperature in the outer peripheral portion. It prevents crystallization and effectively sublimates the silicon carbide raw material loaded in the raw material filling portion, that is, the crystallization rate of the silicon carbide raw material [= (weight of grown silicon carbide single crystal ingot) / (of the loaded silicon carbide raw material] Weight)) can be increased.

  Further, according to the method for producing a silicon carbide single crystal ingot of the present invention, the sublimation gas is efficiently and stably supplied to the crystal growth surface of the seed crystal, and the sublimation gas is supplied to the crystal growth surface of the seed crystal. It is possible to suppress the occurrence of defects due to fluctuations in supply, and it is possible to manufacture a high-quality silicon carbide ingot. Moreover, if a silicon carbide single crystal substrate for an electronic material is manufactured using a high quality silicon carbide single crystal ingot manufactured by the method of the present invention, the yield of the substrate manufactured with respect to the silicon carbide raw material is improved. In addition, the cost of the silicon carbide single crystal substrate can be reduced.

FIG. 1 is an explanatory view showing the entire manufacturing apparatus for a silicon carbide single crystal ingot used in Example 1 of the method for manufacturing a silicon carbide single crystal ingot of the present invention. FIG. 2 is an enlarged explanatory view for explaining the graphite crucible used in Example 1 of the present invention. FIG. 3 is an explanatory view similar to FIG. 2 for explaining the graphite crucible used in Example 2 of the present invention. FIG. 4 is an explanatory view similar to FIG. 2 for explaining the graphite crucible used in Example 3 of the present invention. FIG. 5 is an explanatory view similar to FIG. 2 for explaining the graphite crucible used in Example 4 of the present invention. FIG. 6 is an explanatory diagram for explaining the principle of the improved Rayleigh method.

  Hereinafter, using a silicon carbide single crystal ingot manufacturing apparatus shown in the accompanying drawings, a graphite crucible for manufacturing a silicon carbide single crystal ingot of the present invention, and a method of manufacturing a silicon carbide single crystal ingot of the present invention using this graphite crucible The embodiment will be described.

  FIG. 1 is a diagram for explaining an entire manufacturing apparatus for a silicon carbide single crystal ingot. In this manufacturing apparatus, a graphite crucible 1 made of graphite (hereinafter abbreviated as “crucible”) is placed in a double quartz tube 13. And a heat insulating material 5 made of graphite covering the crucible 1 so as to surround the crucible 1. The crucible 1 is composed of a graphite crucible body 1a formed in a cylindrical shape with an upper end opening and a graphite crucible upper lid 1b that closes the upper end opening, and the crucible body 1a has a lower part. Is provided with a raw material filling portion 1c for filling a silicon carbide raw material (hereinafter simply referred to as "raw material") 3, and a seed crystal 2 made of a silicon carbide single crystal is attached to the inner surface of the crucible upper lid 1b. ing.

In FIG. 1, reference numeral 6 indicates a notch hole, reference numeral 10 indicates a crucible support, reference numeral 13 indicates a double quartz tube, reference numeral 14 indicates a vacuum exhaust device, and reference numeral 15 indicates an Ar gas pipe. Reference numeral 16 denotes a mass flow controller for Ar gas, reference numeral 17 denotes a work coil for high-frequency induction heating for heating the crucible 1 functioning as a heat generating member, and a high-frequency current is passed through the work coil 17 For this purpose, a high-frequency power supply (not shown) is attached.
In FIG. 1, reference numeral 20 denotes a graphite partition wall according to the present invention whose peripheral base is fixed to the inner wall of the side wall of the raw material filling portion 1c and located in the raw material filling portion 1c below the crucible body 1a. A partition opening 21 is formed at the center.

In this manufacturing apparatus, the inside of the double quartz tube 13 can be evacuated to a high vacuum (10 ⁻³ Pa or less) by the vacuum exhaust device 14, and the Ar gas pipe 15 and the Ar gas mass flow controller 16 are used to The pressure of the atmosphere can be controlled with Ar gas. The temperature of the crucible 1 is measured by providing an optical path at the center of the graphite heat insulating material 5 covering the upper and lower parts of the crucible 1, and the upper part of the crucible 1 (crucible upper cover 1b) and the lower part The light from the bottom wall portion of the filling portion 1c (crucible bottom wall portion)] is taken out and performed using a two-color thermometer, the raw material temperature is judged from the temperature at the bottom of the crucible 1, and from the temperature at the top of the crucible 1 The temperature of the seed crystal 2 is judged.
Here, in order to grow a silicon carbide single crystal on the seed crystal 2, a temperature gradient is formed in the vertical direction inside the crucible 1, the temperature of the material filling portion 1c is increased, and the crystal growth portion of the seed crystal 2 is increased. It is necessary to recrystallize at a relatively low temperature. That is, in the crucible 1, it is necessary to form a heat flow from the raw material filling portion 1 c toward the seed crystal 2.

However, in the conventional method (method using the crucible without the partition 20 in FIG. 1), the heat generated by high frequency induction on the side wall of the crucible 1 is passed through the seed crystal 2 from the raw material 3 in the raw material filling portion 1c. Are released outside the system. As a result, the temperature of the outer peripheral portion of the raw material 3 in the raw material filling portion 1 c is high, the temperature decreases toward the vicinity of the central axis, and a temperature gradient is generated toward the seed crystal 2.
In the induction heating by high frequency using such a graphite crucible 1, the side wall of the graphite crucible 1 which is a heat generating member is easily heated, but in the vicinity of the central axis of the raw material 3 in the raw material filling portion 1c (the crucible The vicinity of the central axis of the raw material filling portion 1c at the bottom of the main body 1a is not easily heated. In particular, the bottom of the raw material 3 in the raw material filling portion 1c is a portion in contact with the bottom wall portion of the raw material filling portion below the crucible body 1a of the crucible 1 (hereinafter sometimes simply referred to as “crucible bottom wall portion”). Since the heat input to the raw material 3 in the raw material filling part 1c flows out from the side wall of the crucible 1, it is difficult to effectively heat the vicinity of the center of the crucible bottom wall part by high frequency induction heating. Further, the sublimation gas generated from the heated raw material 3 rises vertically upward and generates a flow of recrystallization on the crystal growth surface of the seed crystal 2. That is, the high temperature sublimation gas in the vicinity of the side wall that is easily heated to high temperature goes to the seed crystal 2 without heating other raw material portions.

  Therefore, the present invention utilizes the high-temperature sublimation gas generated by being heated to a high temperature at the outer periphery of the raw material filling portion 1c as a heat source for heating the vicinity of the central axis of the raw material filling portion 1c, that is, in the raw material filling portion 1c. A method of heating so that the high-temperature sublimation gas at the outer peripheral portion of the raw material filling portion 1c is forced to flow in the vicinity of the central axis of the raw material filling portion 1c by using the disk-shaped partition wall 20 having the partition wall opening 21 arranged in It is characterized by the fact that the raw material 3 of the bottom center portion 1b of the crucible is efficiently sublimated while maintaining the temperature gradient necessary for crystal growth on the seed crystal. Hereinafter, the raw material filling portion 1c above the partition wall 20 is referred to as a raw material upper chamber, and the lower raw material filling portion 1c is referred to as a raw material lower chamber.

The partition wall 20 is not particularly defined in terms of its function, but is preferably a material that functions at a high temperature necessary for performing the sublimation recrystallization method, and is a material that does not become an impurity of the growing silicon carbide single crystal. From the viewpoint, a graphite material is preferable.
The upper surface and / or the lower surface of the partition wall 20 may be parallel to the crucible bottom wall portion of the crucible 1 or may be at an angle with respect to the crucible bottom wall portion. In order to achieve this, a thinner thickness is preferable. On the other hand, when the partition wall 20 is produced using a graphite material, the partition wall 20 is eroded by the reaction between the sublimation gas and graphite. Therefore, the thickness of the partition wall 20 is preferably 5 mm or more.

  The partition 20 may have a planar shape or a curved shape on the side facing the raw material lower chamber (lower surface side). The lower surface portion of the partition wall 20 is preferably curved so as to effectively guide the sublimation gas to the vicinity of the central axis of the raw material 3, but if sublimation gas stays on the lower surface side of the partition wall 20, In this case, the sublimation gas may recrystallize, and the raw material 3 may not be used effectively.

  The height position inside the raw material filling portion 1c on the lower surface of the opening of the partition wall 20 that divides the raw material filling portion 1c into the raw material upper chamber and the raw material lower chamber (hereinafter simply referred to as “partition wall height position”) is the raw material filling. The height from the inner surface of the crucible bottom wall of the portion 1c [that is, the upper surface height in the central axis direction of the initial silicon carbide raw material 3 loaded in the raw material filling portion 1c (hereinafter simply referred to as “the upper surface height of the initial charged raw material”). ”]]] Is preferably disposed at a height of 1/3 to 2/3. At this time, the raw material charged in the raw material lower chamber preferably has a volume ratio of 25% to 75% with respect to the raw material charged in the raw material filling portion 1c. If the height of the partition wall 20 is high and the volume ratio of the raw material lower chamber is large, the effect of inducing the flow of the high temperature sublimation gas in the vicinity of the central axis that is a relatively low temperature portion inside the raw material 3 may be reduced. On the contrary, when the height of the partition wall 20 is low and the volume ratio of the raw material lower chamber is small, the effect of inducing the flow of the high temperature sublimation gas in the vicinity of the central axis which is a relatively low temperature portion inside the raw material 3 is Although it is easy to obtain, since the total amount of the raw material 3 loaded in the raw material lower chamber serving as the supply source of the high-temperature sublimation gas is reduced, it is difficult to obtain a sublimation gas sufficient to sufficiently heat the raw material 3 in the vicinity of the central axis. There is a fear.

  The opening area of the partition wall opening 21 of the partition wall 20 is preferably the area of the upper surface of the initial silicon carbide raw material loaded in the raw material filling portion (hereinafter simply referred to as “the area of the upper surface of the initial charged raw material”). ) To 0.1 times to 0.5 times, more preferably 0.15 times to 0.4 times. When the opening area of the partition wall opening is smaller than 0.1 times the area of the upper surface of the initially loaded raw material, the effect of heating the raw material 3 in the vicinity of the central axis of the raw material filling portion 1c is enhanced, but it goes toward the seed crystal 2 There is a possibility that the supply port becomes narrow and it becomes difficult to obtain a stable supply of sublimation gas. Conversely, if the supply port is larger than 0.5 times, the supply port is large and stable supply of sublimation gas is possible, There is a possibility that the effect of heating the raw material 3 in the vicinity of the central axis of the part 1c may not be obtained.

  When a silicon carbide single crystal ingot having a growth height of 40 mm or more and 200 mm or less is manufactured by the manufacturing method of the present invention, the silicon carbide raw material 3 loaded in the crucible 1 can be used effectively, and crystal growth The fluctuation of the crystal growth rate therein becomes small, and a high-quality silicon carbide single crystal can be obtained. For this reason, it becomes possible to produce the silicon carbide single crystal for electronic materials efficiently, and the silicon carbide single crystal ingot can be manufactured at a lower cost.

[Example 1]
In Example 1, the graphite crucible shown in FIG. 2 was used in the manufacturing apparatus shown in FIG. In the raw material filling portion at the lower part of the crucible body of this crucible, the height of the partition wall is a half of the height of the top surface of the initially charged raw material, the upper and lower surfaces are parallel to the bottom wall of the crucible, and the partition opening A disc-shaped graphite partition wall having an opening area of 0.35 times as large as the area of the upper surface of the initially loaded raw material loaded in the raw material filling portion was disposed.
In addition, 2.3 kg of silicon carbide raw material made of silicon carbide crystal powder produced by the Atchison method is charged in the raw material filling portion at the bottom of the crucible body, and the crucible upper lid of the crucible has a diameter as a seed crystal. A 4H polytype silicon carbide single crystal wafer having a (0001) plane of 105 mm was placed.

  The component member composed of the crucible and the like prepared in this manner was placed inside the double quartz tube as described above, and crystal growth of a silicon carbide single crystal was performed according to a conventional method according to the above procedure. That is, after raising the raw material temperature to the target temperature of 2300 ° C., the pressure of Ar in the double quartz tube is reduced to a growth pressure of 1.3 kPa over 30 minutes to start the growth of the silicon carbide single crystal, Was continued for 140 hours to grow a silicon carbide single crystal.

  As a result, a single crystal ingot having a growth rate of about 0.4 mm / hour, a silicon carbide single crystal diameter of about 105 mm, and a height of about 55 mm was obtained. When the residue of the raw material in the crucible was observed, it was found that the raw material was efficiently sublimated even in the vicinity of the central axis of the raw material, and the heating temperature for the raw material could be effectively changed during high frequency induction heating. As a result, the raw material near the central axis could also be heated efficiently. Further, the weight of the obtained single crystal ingot was about 1.5 kg, and the crystallization rate was 68%.

Furthermore, when the obtained silicon carbide single crystal ingot was analyzed by X-ray diffraction and Raman scattering, it was an ingot consisting of a single polytype of 4H, and it was extremely high quality with few crystal defects such as micropipes. It was confirmed.
The silicon carbide single crystal substrate cut out from the ingot is useful as a substrate for manufacturing an electronic device.

[Example 2]
In Example 2, in place of the graphite crucible shown in FIG. 2 of Example 1, in the manufacturing apparatus using the graphite crucible shown in FIG. 3, the peripheral base is 1 of the upper surface height of the initial charged raw material from the crucible bottom wall. / 3, the partition opening side is slightly higher than the peripheral base side, and the whole is fixed at an angle with the crucible bottom wall, the upper surface is flat and the lower surface is concave, A disc-shaped partition wall having a shape in which the flow of sublimation gas in the lower chamber is guided near the center axis of the raw material was disposed. Moreover, the opening area of the partition wall opening was set to 0.15 times the area of the upper surface of the initially loaded raw material.
In addition, 4.6 kg of silicon carbide raw material made of silicon carbide crystal powder produced by the Atchison method is loaded in the raw material filling portion at the bottom of the crucible body, and the crucible upper lid of the crucible has a diameter as a seed crystal. A 4H polytype silicon carbide single crystal wafer having a (0001) plane of 155 mm was placed.

  The component member composed of the crucible and the like prepared in this manner was placed inside the double quartz tube as described above, and crystal growth of a silicon carbide single crystal was performed according to a conventional method according to the above procedure. That is, after raising the raw material temperature to the target temperature of 2300 ° C., the pressure of Ar in the double quartz tube is reduced to a growth pressure of 1.3 kPa over 30 minutes to start the growth of the silicon carbide single crystal, Was continued for 140 hours to grow a silicon carbide single crystal.

  As a result, a single crystal ingot having a growth rate of about 0.4 mm / hour, a silicon carbide single crystal diameter of about 155 mm, and a height of about 55 mm was obtained. When the residue of the raw material in the crucible was observed, it was found that the raw material was efficiently sublimated even in the vicinity of the central axis of the raw material, and the heating temperature for the raw material could be effectively changed during high frequency induction heating. As a result, the raw material near the central axis could also be heated efficiently. Further, the weight of the obtained single crystal ingot was about 3.3 kg, and the crystallization rate was 72%.

Furthermore, when the obtained silicon carbide single crystal ingot was analyzed by X-ray diffraction and Raman scattering, it was an ingot consisting of a single polytype of 4H, and it was extremely high quality with few crystal defects such as micropipes. It was confirmed.
The silicon carbide single crystal substrate cut out from the ingot is useful as a substrate for manufacturing an electronic device.

Example 3
In Example 3, instead of the graphite crucible shown in FIG. 2 of Example 1, in the manufacturing apparatus using the graphite crucible shown in FIG. 4, the peripheral base is 2 from the crucible bottom wall to the upper surface height of the initial charged raw material. / 3, the partition opening side is slightly lower than the peripheral base upper surface, the upper surface is fixed at an angle with the crucible bottom wall, the upper surface is flat and the lower surface is concave, A disc-shaped partition wall having a shape in which the flow of sublimation gas in the lower chamber is guided near the center axis of the raw material was disposed. In addition, the opening area of the partition opening was set to 0.4 times the area of the upper surface of the initially loaded raw material.
Further, 8.3 kg of silicon carbide raw material made of silicon carbide crystal powder produced by the Atchison method is loaded into the raw material filling portion at the lower part of the crucible body of the crucible, and the crucible upper lid of the crucible has a diameter as a seed crystal. A 4H polytype silicon carbide single crystal wafer having a (0001) plane of 155 mm was placed.

  The component member composed of the crucible and the like prepared in this manner was placed inside the double quartz tube as described above, and crystal growth of a silicon carbide single crystal was performed according to a conventional method according to the above procedure. That is, after raising the raw material temperature to the target temperature of 2300 ° C., the pressure of Ar in the double quartz tube is reduced to a growth pressure of 1.3 kPa over 30 minutes to start the growth of the silicon carbide single crystal, Was continued for 150 hours to grow a silicon carbide single crystal.

  As a result, a single crystal ingot having a growth rate of about 0.4 mm / hour, a silicon carbide single crystal diameter of about 155 mm, and a height of about 60 mm was obtained. When the residue of the raw material in the crucible was observed, it was found that the raw material was efficiently sublimated even in the vicinity of the central axis of the raw material, and the heating temperature for the raw material could be effectively changed during high frequency induction heating. As a result, the raw material near the central axis could also be heated efficiently. Further, the weight of the obtained single crystal ingot was about 3.7 kg, and the crystallization rate was 80%.

Furthermore, when the obtained silicon carbide single crystal ingot was analyzed by X-ray diffraction and Raman scattering, it was an ingot consisting of a single polytype of 4H, and it was extremely high quality with few crystal defects such as micropipes. It was confirmed.
The silicon carbide single crystal substrate cut out from the ingot is useful as a substrate for manufacturing an electronic device.

Example 4
In Example 4, instead of the graphite crucible shown in FIG. 2 of Example 1, in the manufacturing apparatus using the graphite crucible shown in FIG. 5, the peripheral base is 1 of the upper surface height of the initial charged raw material from the crucible bottom wall. / 2, and the partition opening side is slightly lower than the peripheral base side, and the upper surface and the lower surface are fixed at an angle with the crucible bottom wall, and the upper surface and the lower surface are both planar disks. The partition walls were arranged so that the flow of the sublimation gas in the lower chamber of the raw material was guided near the central axis of the raw material. In addition, the opening area of the partition opening was set to 0.3 times the area of the upper surface of the initially loaded raw material.
In addition, in the raw material filling part at the lower part of the crucible body of the crucible, 3.0 kg of silicon carbide raw material made of silicon carbide crystal powder produced by the Atchison method is loaded, and the crucible upper lid of the crucible has a diameter as a seed crystal. A 4H polytype silicon carbide single crystal wafer having a (0001) plane of 105 mm was placed.

  The component member composed of the crucible and the like prepared in this manner was placed inside the double quartz tube as described above, and crystal growth of a silicon carbide single crystal was performed according to a conventional method according to the above procedure. That is, after raising the raw material temperature to the target temperature of 2300 ° C., the pressure of Ar in the double quartz tube is reduced to a growth pressure of 1.3 kPa over 30 minutes to start the growth of the silicon carbide single crystal, Was continued for 170 hours to grow a silicon carbide single crystal.

As a result, a single crystal ingot having a growth rate of about 0.3 mm / hour, a silicon carbide single crystal diameter of about 105 mm, and a height of about 50 mm was obtained. When the residue of the raw material in the crucible was observed, it was found that the raw material was efficiently sublimated even in the vicinity of the central axis of the raw material, and the heating temperature for the raw material could be effectively changed during high frequency induction heating. As a result, the raw material near the central axis could also be heated efficiently. Further, the weight of the obtained single crystal ingot was about 1.4 kg, and the crystallization rate was 47%.
In the case of Example 4, the effect of the present invention can be obtained. However, it is observed that the raw material in the raw material lower chamber is recrystallized on the lower surface side of the peripheral base of the partition wall. The rate was found to be low. That is, in order to make the most effective use of the raw material, it is preferable that the sublimation gas does not easily stay in the peripheral base of the lower raw material chamber.

Furthermore, when the obtained silicon carbide single crystal ingot was analyzed by X-ray diffraction and Raman scattering, it was an ingot consisting of a single polytype of 4H, and it was extremely high quality with few crystal defects such as micropipes. It was confirmed.
The silicon carbide single crystal substrate cut out from the ingot is useful as a substrate for manufacturing an electronic device.

[Comparative Example 1]
For comparison with Example 3, crystal growth was performed under the same operating conditions as in Example 3 without arranging the partition walls 20.
As a result, an ingot having a crystal diameter of about 155 mm and a height of about 20 mm was obtained. When the residue of the raw material in the crucible was observed, recrystallization of the raw material was observed on the central axis of the raw material. Since the raw material in the vicinity of the central axis is not effectively heated, it is considered that the raw material gas sublimated in the peripheral portion of the raw material is recrystallized in the vicinity of the central axis of the raw material without being used for crystal growth. Due to the recrystallization of the sublimation gas in the vicinity of the central axis of the raw material, the supply of the raw material gas was interrupted during the crystal growth, the growth surface of the grown crystal was sublimated, and the growth surface was carbonized. Therefore, the crystallization rate of the ingot was as low as 15%.

  Since the obtained silicon carbide single crystal ingot had a low ingot height, there was a problem that the yield when cutting out a substrate for manufacturing an electronic device was low. In addition, there is a problem that the weight of the ingot is small with respect to the loaded raw material and the raw material cannot be used effectively.

  DESCRIPTION OF SYMBOLS 1 ... Crucible, 1a ... Crucible body, 1b ... Crucible top cover, 1c ... Raw material filling part, 2 ... Seed crystal, 3 ... Silicon carbide raw material (raw material), 4 ... Single-crystal ingot, 5 ... Thermal insulation, 6 ... Notch hole , 10 ... crucible support, 13 ... double quartz tube, 14 ... vacuum exhaust device, 15 ... Ar gas pipe, 16 ... mass flow controller for Ar gas, 17 ... work coil, 20 ... partition, 21 ... partition opening.

Claims (3)

A graphite crucible body formed in a cylindrical shape with an upper end opening and a graphite crucible upper lid for closing the upper end opening of the crucible body, and a raw material filling portion for filling a silicon carbide raw material at the lower part of the crucible body The silicon carbide raw material charged in the raw material filling portion is heated and sublimated, and the generated sublimation gas is recrystallized on the surface of a seed crystal made of a silicon carbide single crystal installed on the inner surface of the crucible upper lid In a graphite crucible for producing a silicon carbide single crystal by a sublimation recrystallization method,
In the raw material filling part at the lower part of the crucible body, a peripheral base is fixed to the inner surface of the side wall of the raw material filling part, and a disk-shaped graphite partition wall having a partition opening is provided at a substantially central part. A graphite crucible for producing a silicon carbide single crystal ingot.   The opening area of the partition wall opening of the graphite partition wall is 0.1 to 0.5 times the area of the upper surface of the initial silicon carbide raw material loaded in the raw material filling portion. 2. A graphite crucible for producing a silicon carbide single crystal ingot according to 1. A graphite crucible body formed in a cylindrical shape with an upper end opening and a crucible upper lid for closing the upper end opening of the crucible body, and a graphite having a raw material filling portion for filling a silicon carbide raw material at the lower part of the crucible body Using a crucible, a silicon carbide raw material is loaded into the raw material filling portion at the bottom of the crucible body of the graphite crucible, a seed crystal made of a silicon carbide single crystal is placed on the inner surface of the crucible upper lid, and the side surface of the crucible body is guided at high frequency. In a method for producing a silicon carbide single crystal by heating to generate a sublimation gas and recrystallizing the generated sublimation gas on the seed crystal,
The raw material filling portion at the lower part of the crucible body is provided with a disk-shaped graphite partition wall having a peripheral base fixed to the inner wall surface of the crucible body and having a partition wall opening at a substantially central portion. A silicon carbide single crystal ingot characterized by guiding the generated sublimation gas in a direction toward the central axis of the raw material filling portion and heating the silicon carbide raw material located around the central axis in the raw material filling portion to a sublimation temperature. Production method.

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