JP2009298611A - Production method of semiconductor crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for suppressing production of polycrystals near the final solidified portion of an ingot and suppressing generation of dislocations near the final solidified portion. <P>SOLUTION: The production method of a semiconductor crystal comprises, while allowing a seed crystal 30 placed in the bottom of a crucible 20 to be in contact with a semiconductor melt 100 stored in the crucible 20, gradually solidifying the semiconductor melt 100 upward from the seed crystal 30 side, wherein a liquid sealing material 110 and a heat ray transmission suppressing material 120 are disposed on the semiconductor melt 100, so as to allow the liquid sealing material 110 to suppress volatilization of a component from the semiconductor melt 100 and the heat ray transmission suppressing material 120 to suppress transmission of heat rays from the semiconductor melt 100 through the liquid sealing material 110. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semiconductor crystal manufacturing method for gradually solidifying a semiconductor melt.

Conventionally, as a vertical boat growth method for growing a single crystal of a compound semiconductor, a seed crystal placed at the bottom of a crucible and a semiconductor melt (raw material melt) accommodated in the crucible are brought into contact with each other. A vertical gradient freezing (vertical gradient: VGF) method, a vertical bridgman (VB) method, and the like are known in which a semiconductor crystal is grown by gradually solidifying from the seed crystal side upward. In addition, on the semiconductor melt, a liquid sealing material made of, for example, boron trioxide (B ₂ O ₃ ) or the like is used in order to suppress volatilization of the raw material components from the semiconductor melt (for example, volatilization of group V elements). Provided. The liquid sealing material is softened by heating the inside of the crucible and hermetically seals the surface of the semiconductor melt (see, for example, Patent Documents 1 to 3).

For example, Patent Document 1 includes a container for storing a raw material melt, a temperature gradient furnace disposed around the container, and means for moving the temperature gradient furnace relative to the container, and one end of the container A single crystal manufacturing apparatus using a pBN container containing B ₂ O ₃ in the wall of a container is disclosed. According to the single crystal manufacturing apparatus described in Patent Document 1, B ₂ O ₃ gradually oozes out from the wall surface of the pBN container during use, and the wall surface of the crucible is covered with the B ₂ O ₃ film. Generation of crystal nuclei caused by contact between the liquid and the irregular wall surface of the crucible surface can be prevented.

  Patent Document 2 discloses a method for producing a single crystal using a raw material melt container, a container comprising a seed crystal container provided at the bottom of the raw material melt container, and a liquid sealing material. Is disclosed. According to the single crystal manufacturing method described in Patent Document 2, it is possible to prevent the occurrence of polycrystals and twins by defining the tolerance between the outer diameter of the seed crystal and the inner diameter of the seed crystal housing portion of the container.

Further, in Patent Document 3, in the vertical boat method using a liquid sealing material, crystal growth is performed while boron arsenide is suspended at the interface between the raw material GaAs melt and the liquid sealing material B ₂ O _3. A crystal growth method to perform is disclosed. According to the single crystal manufacturing method described in Patent Document 3, it is possible to prevent the occurrence of dislocation due to the precipitation of boron arsenide during crystal growth.
Japanese Patent No. 2558515 JP 2002-121100 A JP 2004-115339 A

  However, in the conventional vertical boat growth method, it is easy to polycrystallize near the final solidified part (tail part) of the grown semiconductor crystal (hereinafter also referred to as ingot), and it is difficult to make a single crystal over the entire length of the ingot. there were. Moreover, even when single crystallization can be performed over the entire length of the ingot, the dislocation density near the final solidified portion of the ingot increases compared to the dislocation density of other portions, and the dislocation density is uneven. There was a case.

  An object of the present invention is to provide a semiconductor crystal manufacturing method capable of suppressing polycrystallization near the final solidified portion of an ingot and suppressing the occurrence of dislocations near the final solidified portion.

  According to the first aspect of the present invention, the semiconductor melt is directed upward from the seed crystal side while contacting the seed crystal disposed at the bottom of the crucible with the semiconductor melt accommodated in the crucible. In the method of manufacturing a semiconductor crystal to be gradually solidified, a liquid sealing material and a heat ray permeation suppression material are provided on the semiconductor melt, and the liquid sealing material is configured to suppress volatilization of components from the semiconductor melt. The heat ray permeation suppressing material is provided with a semiconductor crystal manufacturing method for suppressing heat ray permeation from the semiconductor melt via the liquid sealing material.

  According to the second aspect of the present invention, the seed crystal is disposed at the bottom of the crucible, the semiconductor raw material, the sealing material, and the heat ray permeation suppressing material are accommodated in the crucible, the crucible is heated, and the semiconductor The seed crystal and the semiconductor melt are brought into contact with each other by generating in the crucible a semiconductor melt obtained by melting a raw material and a liquid sealing material obtained by softening the sealing material. A method for producing a semiconductor crystal is provided, wherein the liquid sealing material and the heat ray permeation suppressing material are provided on the semiconductor crystal, and the semiconductor melt is gradually solidified upward from the seed crystal side.

  According to the 3rd aspect of this invention, the manufacturing method of the semiconductor crystal as described in the 1st or 2nd aspect which floats the said heat ray permeation | transmission suppression material on the said liquid sealing material is provided.

  According to the 4th aspect of this invention, the manufacturing method of the semiconductor crystal as described in the 1st or 2nd aspect which provides the said heat ray permeation | transmission suppression material in the said liquid sealing material is provided.

  According to a fifth aspect of the present invention, there is provided the method for producing a semiconductor crystal according to any one of the first to fourth aspects, wherein the heat ray permeation suppression material is made of a material containing carbon.

  According to a sixth aspect of the present invention, there is provided the method for producing a semiconductor crystal according to any one of the first to fourth aspects, wherein the heat ray transmission suppressing material is made of a material containing an oxide.

  According to the semiconductor crystal manufacturing method of the present invention, it is possible to suppress polycrystallization near the final solidified portion of the ingot, and to suppress the occurrence of dislocations near the final solidified portion.

  In order to produce a single crystal by the vertical boat growth method, it is necessary to form a predetermined temperature gradient in the semiconductor melt accommodated in the crucible. That is, it is necessary to form a temperature gradient in the semiconductor melt such that the lower side (seed crystal side) in the semiconductor melt is a low temperature and the upper side (semiconductor melt surface side) is a high temperature. If such a temperature gradient is formed, crystal growth gradually proceeds from the bottom to the top of the semiconductor melt, polycrystallization is suppressed, and it becomes easy to form a single crystal over the entire length of the ingot. .

  In order to form such a temperature gradient in the semiconductor melt, it is necessary to suppress heat dissipation from the surface of the semiconductor melt to the space above the semiconductor melt. This is because a very large temperature difference exists between the semiconductor melt and the space above the semiconductor melt. For example, when manufacturing a GaAs single crystal, the semiconductor melt in the crucible is heated to a temperature of 1238 ° C. or higher. On the other hand, when the chamber containing the crucible is a general stainless steel chamber provided with a water cooling jacket, the inner wall temperature of the chamber is 200 ° C. or lower. Even if a heat insulating material is provided between the inner wall of the chamber and the semiconductor melt, the temperature of the heat insulating material facing the semiconductor melt surface is often as low as several hundred degrees Celsius.

As described above, the surface of the semiconductor melt is hermetically sealed with B ₂ O ₃ as a liquid sealing material. Since B ₂ O ₃ is generally a material having low thermal conductivity, it suppresses heat radiation due to heat conduction from the surface of the semiconductor melt to the space above the semiconductor melt. However, the inventor's diligent research has revealed that even if the heat dissipation due to heat conduction is suppressed in this way, if the crystal growth reaches the final stage, the above temperature gradient may not be maintained.

Although B ₂ O ₃ constituting the liquid sealing material has a low thermal conductivity, it is a substantially transparent material for infrared rays. Therefore, there is always heat dissipation from the semiconductor melt due to radiation through the liquid sealing material. According to the inventor's knowledge, the effect of heat dissipation due to radiation is small when the remaining amount of semiconductor melt is large, but the crystal growth is approaching the final stage, and the effect of heat dissipation due to radiation when the remaining amount of semiconductor melt in the crucible decreases. Can no longer be ignored. That is, when the remaining amount of the semiconductor melt decreases (when the heat capacity of the semiconductor melt decreases), the amount of temperature drop due to radiation increases, and the temperature near the surface of the semiconductor melt rapidly decreases, and the semiconductor melt It is difficult to maintain the above-described temperature gradient in which the lower side of the temperature is low and the upper side is high. As a result, new crystal growth nuclei are generated in places other than the crystal growth interface (solid-liquid interface), and the vicinity of the final solidified portion of the ingot is easily polycrystallized.

  Further, according to the earnest study of the inventors, the final solidified part of the ingot is compared with other parts when the ingot is gradually cooled after the crystal growth is finished due to the influence of heat radiation due to radiation through the liquid sealing material. As a result, the thermal stress in the vicinity of the final solidified part becomes larger than the thermal stress in other parts, and it has been found that dislocations are likely to occur in the vicinity of the final solidified part.

  As described above, the inventor is effective in suppressing heat dissipation due to radiation through the liquid sealing material in order to suppress polycrystallization in the vicinity of the final solidified portion of the ingot and reduce the dislocation density. I got the knowledge. The present invention is an invention made based on such knowledge obtained by the inventor.

<First Embodiment of the Present Invention>
A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional configuration diagram of a crystal growth furnace for performing a semiconductor crystal manufacturing method according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the vicinity of the surface of the semiconductor melt according to the first embodiment of the present invention. FIG. 5 is a flowchart illustrating the method for manufacturing the semiconductor crystal according to the first embodiment of the invention.

(1) Configuration of Crystal Growth Furnace As shown in FIG. 1, the crystal growth furnace 1 according to this embodiment includes a chamber 70 configured as an airtight container. Inside the chamber 70 are a crucible 20 as a heat-resistant container for containing raw materials and the like, a susceptor 50 as a crucible container for containing the crucible 20, a susceptor support member 55 for holding the susceptor 50 from below, and a susceptor 50. And an outer peripheral heater composed of ring-shaped outer peripheral heater units 12a to 12d for heating the crucible 20 from the side surface. Further, a heat insulating material 60 is provided in the chamber 70 so as to surround the outer periphery and the upper part of the outer peripheral heater, and the inner space of the heat insulating material 60 is vertically arranged between the outer peripheral heater units 12b and 12c. A heat insulating material 62 for sorting is provided. Although not shown, the crystal growth furnace 1 includes a thermocouple that detects the temperatures of the susceptor 50 and the heater units 12a to 12d, a gas supply unit that supplies a predetermined gas into the chamber 70, Gas pressure control means for keeping the pressure at a constant value.

The crucible 20 includes a narrow diameter portion 25 as a seed crystal arrangement portion that accommodates a seed crystal 30 of a semiconductor crystal, a conical inclined portion 26 that is joined to the upper portion of the small diameter portion 25 at a predetermined angle, and an inclined portion 26. And a straight body part 27 joined so as to stand in a substantially vertical direction. The small diameter portion 25 and the inclined portion 26 constitute the bottom of the crucible 20. The longitudinal direction of the small diameter portion 25 and the straight body portion 27
Is provided substantially in parallel with the body portion. The straight body portion 27 is formed in a substantially cylindrical shape having a cross-sectional diameter of, for example, 160 mm and a height of, for example, 300 mm. An opening 22 that exposes the inside of the crucible 20 is formed at the upper end of the straight body portion 27. The crucible 20 is made of, for example, pyrolytic boron nitride (pBN). The crucible 20 may be made of quartz.

In the narrow diameter portion 25 of the crucible 20, for example, a GaAs single crystal is accommodated as the seed crystal 30. In the crucible 20 (inside the inclined part 26 and the straight body part 27), for example, massive GaAs polycrystal is accommodated (filled) as the main raw material of the semiconductor crystal. Furthermore, the crucible 20 is configured so that a predetermined amount of a liquid sealing material 110 such as B ₂ O ₃ that is solid at room temperature and a heat ray permeation suppression material to be described later are accommodated inside the crucible 20. In the case of manufacturing a p-type or n-type semiconductor crystal, the crucible 20 is configured so that, for example, a zinc (Zn) element or a silicon (Si) element as a dopant material is further accommodated therein. Yes. The dopant material may be added in advance to the massive GaAs polycrystal.

  The massive GaAs polycrystal as the main raw material is melted when the inside of the crucible 20 is heated to, for example, 1238 ° C. or more to become the semiconductor melt 100. The lower part of the generated semiconductor melt 100 is configured to contact the upper end of the seed crystal 30. Further, the liquid sealing material 110 is configured to be softened by heating the inside of the crucible 20 and hermetically seal the surface of the semiconductor melt 100. The thickness of the liquid sealing material 110 that seals the surface of the semiconductor melt 100 is preferably a thickness that allows the liquid sealing material 110 to cover the entire surface of the semiconductor melt 100. According to the cross-sectional diameter of the straight body part 27, it is appropriately adjusted within a range of 5 mm to 20 mm.

  The heat ray permeation suppression material according to the present embodiment is made of a material having an action of absorbing heat rays, for example, a material containing carbon. Specifically, the heat ray permeation suppression material according to the present embodiment is configured as a porous carbon piece or a molded product, for example, a carbon bead 120. In addition, the heat ray permeation suppression material according to the present embodiment is not limited to a carbon piece, a molded product piece, or a molded product, and may be made of a carbon fiber material.

  The beads 120 as the heat ray permeation suppression material are preferably configured to float on the softened liquid sealing material 110. Such a situation is shown in FIG. For this reason, it is comprised so that specific gravity may become light in order of the semiconductor melt 100, the liquid sealing material 110, and the bead 120 (specific gravity of the semiconductor melt 100> specific gravity of the liquid sealing material 110> specific gravity of the bead 120). Is preferred. By configuring the beads 120 to be porous, the above-described specific gravity relationship can be realized. However, if the beads 120 do not sink or settle in the liquid sealing material 110, it is not always necessary to satisfy the above-described specific gravity relationship. This is because the liquid sealing material 110 has a high viscosity, so that even if the relationship of specific gravity of the liquid sealing material 110> specific gravity of the beads 120 is not satisfied, a phenomenon that the beads 120 sink or precipitate does not easily occur. The particle size of the beads 120 is preferably set to, for example, about several mm so that the beads 120 are uniformly dispersed on the surface of the liquid sealing material 110 and the surface of the liquid sealing material 110 is covered without any gap. The amount of the beads 120 is such that the entire surface of the liquid sealing material 110 can be covered, and at least the liquid sealing material 110 and the semiconductor melt 100 are covered with the beads 120 when viewed from the upper surface of the crucible 20. The amount is preferably such that it is hidden and cannot be seen. For example, the amount is preferably such that it can be covered with a thickness of about 5 mm. The beads 120 are preferably subjected to high-purity treatment in order to prevent contamination of the semiconductor melt 100 and the liquid sealing material 110.

The susceptor 50 is made of graphite, for example, and is configured to accommodate and hold the crucible 20 therein. The susceptor support member 55 is configured to support the susceptor 50 from below. The susceptor support member 55 is configured to freely move up and down and rotate in the crystal growth furnace 1. By rotating the susceptor support member 55 during crystal growth, the temperature distribution in the crucible 20 can be maintained substantially constant and constant. By lowering the susceptor support member 55, the crucible 20 is lowered (drawn) from the outer peripheral heater units 12a to 12d, and the melt is solidified from the seed crystal side while maintaining a desired temperature gradient in the crucible 20. Is configured to be possible.

  As described above, the outer peripheral heater includes ring-shaped outer peripheral heater units 12 a to 12 d that heat the crucible 20 from the side surface via the susceptor 50. The peripheral heater units 12a to 12d are sequentially arranged along the direction from the upper part to the lower part in the crystal growth furnace 1. Specifically, the outer peripheral heater unit 12a is near the opening 22 of the crucible 20, the outer peripheral heater unit 12b is under the outer heater unit 12a, and the outer heater unit 12c is under the outer heater unit 12b. In the vicinity of the small diameter portion 25, the outer peripheral heater unit 12d is disposed below the outer peripheral heater unit 12c.

  The set temperatures of the outer peripheral heater units 12a to 12d are set so as to sequentially decrease along the direction from the upper part to the lower part of the crystal growth furnace 1. That is, the temperature is set such that the set temperature of the outer peripheral heater unit 12a> the set temperature of the outer heater unit 12b> the set temperature of the outer heater unit 12c> the set temperature of the outer heater unit 12d.

  The outer peripheral heater units 12a to 12d are configured as resistance heaters formed from a material such as graphite, for example. The outer peripheral heater units 12a to 12d are not limited to the above configuration, and may be configured as a silicon carbide (SiC) heater, a Kanthal wire heater, a heater using a heating element heated by an RF coil as a secondary heater, or the like. It is.

  As described above, the heat insulating material 60 that surrounds the outer periphery and the upper portion of the outer peripheral heater is provided in the chamber 70. The heat insulating material 60 is made of, for example, a graphite heat insulating material, carbon felt, or the like, and suppresses the heat generated from the outer peripheral heater from being transmitted to the inner wall of the chamber 70, and the heat generated from the outer peripheral heater is crucible. It functions to efficiently transmit to 20.

  A heat insulating material 62 that divides the internal space of the heat insulating material 60 in the vertical direction is provided between the outer peripheral heater units 12b and 12c. The heat insulating material 62 is made of, for example, a graphite molded heat insulating material, carbon felt, or the like, and functions to ensure a predetermined temperature difference between a space above the heat insulating material 62 and a lower space.

(2) Semiconductor Crystal Growth Method A semiconductor crystal manufacturing method performed by the above-described crystal growth furnace 1 will be described below with reference to FIG. In the following description, an example of manufacturing an undoped crystal in which no dopant material is added to a semiconductor crystal will be described.

A GaAs single crystal as a seed crystal 30 is accommodated in the small diameter portion 25 of the crucible 20 (S100), and a massive GaAs polycrystal as a main material in the crucible 20 (inside the inclined portion 26 and the straight body portion 27). Is stored (filled) (S105), and B ₂ O ₃ as the liquid sealing material 110 and carbon beads 120 as the heat ray permeation suppression material are stored in the crucible 20 (S110).

Then, the crucible 20 containing the seed crystal 30, the GaAs polycrystal, the liquid sealing material 110, and the heat ray transmission suppressing material is housed in the susceptor 50 (S 115), and the susceptor 50 is mounted on the susceptor support member 55. (S120). Next, the crystal growth furnace 1 (chamber 70) is sealed, and the inside of the crystal growth furnace 1 (chamber 70) is replaced with, for example, nitrogen gas as an inert gas (
In S125, the susceptor support member 55 is rotated to start the rotation of the crucible 20 (S130). The rotation of the crucible 20 is continued until crystal growth described later is completed.

  And it supplies with electricity to each of the some outer periphery heater unit 12a-12d, and the heating of the crucible 20 is started (S135). By continuing the heating of the crucible 20 for a predetermined time, the GaAs polycrystal in the crucible 20 is completely melted to form the semiconductor melt 100 (S140). When the heating of the crucible 20 is started, the volume of the atmospheric gas in the chamber 70 expands, so that the pressure in the chamber 70 is controlled by the gas pressure control means so that the pressure in the chamber 70 does not exceed a predetermined pressure during crystal growth. Control the pressure.

  In addition, the liquid sealing material 110 accommodated in the crucible 20 softens faster than the GaAs polycrystal as the main raw material melts and becomes a transparent water tank. Since the specific gravity of the liquid sealing material 110 is smaller than the specific gravity of the semiconductor melt 100, the softened liquid sealing material 110 floats on the semiconductor melt 100 to airtight the surface of the semiconductor melt 100. Seal. The liquid sealing material 110 acts to suppress volatilization of components (for example, As element) from the semiconductor melt 100.

  Further, since the specific gravity of the heat ray permeation suppression material (bead 120) is smaller than the specific gravity of the liquid sealing material 110, the bead 120 floats on the liquid sealing material 110 and floats on the surface of the liquid sealing material 110. Cover the entire surface. The operation of the beads 120 will be described later.

  Subsequently, the set temperatures of the outer peripheral heater units 12a to 12d are respectively set to temperatures that gradually decrease from the top to the bottom of the crystal growth furnace 1 (S145). For example, the set temperature of the outer peripheral heater unit 12a arranged at the top is 1290 ° C, the set temperature of the outer heater unit 12b is 1260 ° C, the set temperature of the outer heater unit 12c is 1120 ° C, Are set to 1050 ° C., respectively.

  Thereafter, the semiconductor melt 100 is held for a predetermined time until the temperature of the melt 100 is stabilized (S150). In step S150, the height position of the crucible 20 with respect to the outer heater (outer heater units 12a to 12d) is determined based on a temperature distribution measured in advance by inserting a thermocouple into the crystal growth furnace 1. Is preferred. Specifically, an isotherm of 1238 ° C. (melting point of GaAs) in the semiconductor melt 100 is an upper end portion of the seed crystal 30 so that the seed crystal 30 does not melt and disappear in steps S145 to S150. It is preferable to arrange the crucible 20 at such a height position.

  After the temperature of the semiconductor melt 100 is stabilized, the susceptor support member 55 is lowered a predetermined distance at a predetermined speed per hour while the rotation of the crucible 20 is continued (S155). When the crucible 20 is lowered by a predetermined distance, the lowering of the crucible 20 is stopped.

  By gradually lowering the crucible 20 in this manner, the semiconductor melt 100 passes through a temperature gradient in which the lower side in the semiconductor melt 100 is a low temperature and the upper side is a high temperature. Then, crystal growth started at the solid-liquid interface between the seed crystal 30 and the semiconductor melt 100 proceeds gradually from the bottom to the top of the semiconductor melt 100.

The beads 120 floating on the liquid sealing material 110 absorb the heat rays from the semiconductor melt 100 through the liquid sealing material 110, that is, absorb the heat rays from the semiconductor melt 100 and radiate. It functions to suppress upward heat dissipation from the semiconductor melt 100. For this reason, even when the crystal growth reaches the final stage and the remaining amount of the semiconductor melt 100 in the crucible 20 is reduced, the temperature drop of the semiconductor melt 100 due to radiation can be suppressed. That is, a temperature gradient is maintained such that the lower side in the semiconductor melt 100 is a low temperature and the upper side is a high temperature. As a result, the crystal growth gradually proceeds from the bottom to the top of the semiconductor melt until the crystal growth is completed, and polycrystallization near the final solidified portion is suppressed, making it easy to obtain a single crystal over the entire length of the ingot.

  When the lowering of the crucible 20 is stopped, the temperature of the outer peripheral heater units 12a to 12d is gradually lowered to gradually cool the ingot (S160). When the temperature of the outer peripheral heater units 12a to 12d decreases to a predetermined temperature, the energization to the outer peripheral heater units 12a to 12d is stopped, and the ingot is gradually cooled by gradually cooling the temperature of the crucible 20 to room temperature. Then, the semiconductor crystal growth method according to the present embodiment is completed (S165).

  In order to gradually cool the ingot, it is preferable to uniformly lower the temperature of each part in the ingot so that a temperature difference does not occur in the ingot. However, if it is attempted to achieve a predetermined temperature drop within a predetermined time, a temperature difference tends to occur in the ingot. For example, if no heating means or heat insulating material is provided on the top of the ingot (or the distance is long even if it is provided), the amount of heat released toward the top of the ingot becomes too large. A temperature difference is likely to occur in the ingot. According to the present embodiment, since the transmission of heat rays through the liquid sealing material 110 is suppressed by the beads 120 floating on the liquid sealing material 110, when the ingot is gradually cooled after the crystal growth is completed. It can prevent that the last solidification part of an ingot becomes easy to be cooled compared with another site | part. For this reason, the thermal stress in the vicinity of the final solidified portion is suppressed from becoming larger than the thermal stress in other portions, the occurrence of dislocations in the vicinity of the final solidified portion is suppressed, and the dislocation density distribution is made uniform over the entire area of the ingot.

(3) Effects according to the present embodiment According to the present embodiment, one or more effects described below are produced.

  According to the present embodiment, the beads 120 as the heat ray permeation suppression material function to suppress the transmission of heat rays from the semiconductor melt 100 via the liquid sealing material 110. For this reason, even when the crystal growth reaches the final stage and the remaining amount of the semiconductor melt 100 in the crucible 20 is reduced, the temperature drop of the semiconductor melt 100 due to radiation can be suppressed. That is, a temperature gradient is maintained such that the lower side in the semiconductor melt 100 is a low temperature and the upper side is a high temperature. As a result, until the crystal growth is completed, the crystal growth gradually proceeds from the bottom to the top of the semiconductor melt, the polycrystallization near the final solidified portion is suppressed, and a single crystal can be easily obtained over the entire length of the ingot. .

  According to the present embodiment, the beads 120 as the heat ray permeation suppressing material function to suppress the heat ray permeation through the liquid sealing material 110. For this reason, after the crystal growth is completed, it is possible to prevent the final solidified portion of the ingot from being cooled more easily than other portions, and the thermal stress in the vicinity of the final solidified portion is larger than the thermal stress in other portions. The generation of dislocations in the vicinity of the final solidified portion is suppressed, and the dislocation density distribution is made uniform over the entire area of the ingot.

  According to this embodiment, it is comprised so that specific gravity may become light in order of the semiconductor melt 100, the liquid sealing material 110, and the bead 120. As a result, during crystal growth, the liquid sealing material 110 hermetically seals the surface of the semiconductor melt 100, and the beads 120 float on the liquid sealing material 110. That is, since the semiconductor melt 100 and the beads 120 are not in direct contact with each other, the semiconductor melt 100 is prevented from being contaminated by the beads 120.

According to the present embodiment, the beads 120 are configured to float on the liquid sealing material 110 during crystal growth. Since B ₂ O ₃ constituting the liquid sealing material 110 has a low thermal conductivity, heat conduction from the semiconductor melt 100 to the beads 120 is less likely to occur, and the beads 120 are suppressed from becoming high temperature. The heat radiation due to the radiation is less likely to occur. As a result, a rapid temperature drop near the surface of the semiconductor melt 100 or a rapid temperature drop near the final solidified portion of the ingot can be suppressed.

  According to the present embodiment, the liquid sealing material 110 and the beads 120 are configured to be in close contact during crystal growth. That is, it is configured such that no space is interposed between the liquid sealing material 110 and the bead 120 or that the space interposed between the liquid sealing material 110 and the bead 120 is small. That is, there is no atmospheric gas between the liquid sealing material 110 and the beads 120, or even if it exists, the amount is very small. If there is a space between the liquid sealing material 110 and the beads 120, the semiconductor melt 100 may be disturbed in temperature due to the influence of convection of the atmospheric gas existing therebetween. According to this embodiment, it is configured so that no space is interposed between the liquid sealing material 110 and the beads 120 or the space interposed between the liquid sealing material 110 and the beads 120 is small. Therefore, the generation of convection of the atmospheric gas between the liquid sealing material 110 and the beads 120 is suppressed, the temperature of the semiconductor melt 100 is hardly disturbed, the crystal growth conditions are stabilized, and the crystal The quality can be stabilized.

  According to this embodiment, heat radiation from the semiconductor melt 100 toward the upper space in the crystal growth furnace 1 can be significantly reduced. Therefore, it is possible to reduce the amount of input electric power necessary for crystal growth, and it is possible to reduce the manufacturing cost of the semiconductor crystal.

<Second Embodiment of the Present Invention>
The present embodiment is different from the above-described embodiment in that the heat ray permeation suppression material is configured as a graphite disk 130 instead of the beads 120 group. Other configurations are the same as those of the first embodiment. FIG. 3 is a schematic cross-sectional view of the vicinity of the surface of the semiconductor melt 100 according to the present embodiment. According to FIG. 3, the surface of the semiconductor melt 100 is hermetically sealed by the softened liquid sealing material 110, and a disk 130 as a heat ray transmission suppressing material floats on the liquid sealing material 110. Yes. In addition, the thickness of the liquid sealing material 110 that seals the surface of the semiconductor melt 100 is in the range of 5 mm to 20 mm, for example, according to the cross-sectional diameter of the straight body portion 27 of the crucible 20 as in the first embodiment. Are adjusted accordingly.

  Note that the specific gravity of the disk 130 is preferably smaller than the specific gravity of the liquid sealing material 110. In addition, the disk 130 is preferably subjected to high-purity processing in order to prevent contamination of the semiconductor melt 100 and the liquid sealing material 110. Further, the disk 130 is sized so as to cover the entire surface of the liquid sealing material 110, and the liquid sealing material 110 and the semiconductor melt 100 can be seen from the upper surface of the crucible 20. It is preferable that the size is such that it is covered and hidden from view.

  The graphite disk 130 functions to suppress the transmission of heat rays from the semiconductor melt 100 via the liquid sealing material 110, similarly to the beads 120 of the first embodiment. For this reason, the same effects as in the first embodiment can be obtained in this embodiment. Furthermore, according to the present embodiment, even if convection or the like occurs in the liquid sealing material 110, the disk 130 (heat ray permeation suppression material) becomes difficult to move on the surface of the liquid sealing material 110, and the liquid It can suppress that the surface of the sealing material 110 is exposed and the heat ray is transmitted, and the temperature condition can be further stabilized.

<Third Embodiment of the Present Invention>
The present embodiment is different from the above-described embodiment in that a heat ray transmission suppressing material is not provided (floating) on the liquid sealing material 110 but a heat ray transmission suppressing material is provided in the liquid sealing material 110. Specifically, the heat ray permeation suppression material according to the present embodiment is configured, for example, as a high-purity carbon fine powder 140 so that the high-purity carbon fine powder 140 is uniformly dispersed in the liquid stopper 110. It is configured. Other configurations are the same as those of the first embodiment. FIG. 4 is a schematic cross-sectional view of the vicinity of the surface of the semiconductor melt 100 according to the present embodiment. According to FIG. 4, the surface of the semiconductor melt 100 is hermetically sealed by the softened liquid sealing material 110, and the fine powder 140 of high-purity carbon is uniformly dispersed in the liquid sealing material 110. Yes. As the fine powder of the high-purity carbon fine powder 140, for example, carbon black which is a fine particle of carbon having a diameter of about 3 to 500 nm manufactured by quality control industrially can be used. The thickness of the liquid sealing material 110 that seals the surface of the semiconductor melt 100 is within the range of 5 mm to 20 mm, for example, according to the cross-sectional diameter of the straight body portion 27 of the crucible 20, as in the first embodiment. It is adjusted appropriately.

  The high-purity carbon fine powder 140 functions to suppress the transmission of heat rays from the semiconductor melt 100 through the liquid sealing material 110, similarly to the bead 120 of the first embodiment. For this reason, the same effects as in the first embodiment can be obtained in this embodiment. Furthermore, according to the present embodiment, even if convection or the like occurs in the liquid sealing material 110, the fine powder 140 of high-purity carbon is uniformly dispersed in the liquid sealing material 110. Transmission of heat rays through the stop material 110 is always suppressed, and temperature conditions can be further stabilized.

  Further, according to the present embodiment, the high purity carbon fine powder 140 is uniformly dispersed in the liquid sealing material 110 so that the high purity carbon fine powder 140 and the semiconductor melt 100 can be brought into contact with each other. It is configured. Therefore, it becomes possible to obtain a semi-insulating semiconductor crystal in which carbon element contained in the fine powder 140 of high-purity carbon is mixed in the semiconductor melt 100 and carbon (C) element is intentionally doped. . In the VGF method, when the surface of the semiconductor melt 100 is sealed with the liquid sealing material 110, for example, the carbon element contained in the atmospheric gas in the chamber 70 is contained in the semiconductor melt 100 compared to the LEC (Liquid Encapsulated Czochralski method). It becomes difficult to mix in. On the other hand, according to the present embodiment, since the high-purity carbon fine powder 140 is dispersed in the liquid sealing material 110, the carbon-containing material is not further accommodated in the crucible 20 in the above-described step S115. The carbon element contained in the high-purity carbon fine powder 140 can be mixed into the semiconductor melt 100.

Also in the present embodiment, it is possible to obtain a semiconductor crystal having a low carbon element concentration by forming the liquid sealing material 110 into a two-layer structure. That is, the surface of the semiconductor melt 100 is sealed with the liquid sealing material 110 in which the high-purity carbon fine powder 140 is not dispersed, while the liquid sealing material 110 in which the high-purity carbon fine powder 140 is not dispersed. By sealing the surface with the liquid sealing material 110 in which the fine powder 140 of high purity carbon is uniformly dispersed, the contact between the fine powder 140 of high purity carbon and the semiconductor melt 100 is suppressed, and the high purity carbon Mixing of the carbon element contained in the fine powder 140 into the semiconductor melt 100 can be suppressed, and the carbon concentration in the semiconductor crystal can be reduced. In such a two-layer structure, the liquid sealing material 110 in which the fine powder 140 of high-purity carbon is not dispersed and the liquid sealing material 110 in which the fine powder 140 of high-purity carbon is dispersed are respectively included in the crucible 20. These discs, which are solid at room temperature, are sequentially stacked and stored in the crucible 20 while being formed into a disc shape according to the inner diameter, and can be formed by heating and softening. Since B ₂ O ₃ has a high viscosity, even if it is softened, the liquid sealing material 110 in which the fine powder 140 of high purity carbon is not dispersed and the liquid sealing material 110 in which the fine powder 140 of high purity carbon is not dispersed. It is considered that the high-purity carbon fine powder 140 and the semiconductor melt 100 are difficult to contact with each other.

<Fourth Embodiment of the Present Invention>
The present embodiment is different from the above-described embodiment in that the heat ray transmission suppressing material is made of a material having an action of reflecting or scattering heat rays, for example, a material containing an oxide. The heat ray permeation suppression material according to the present embodiment is a small piece or molded product of opaque quartz glass that has irregularities on the surface (surface roughing is performed) or contains a large number of extremely small bubbles inside, For example, it is configured as a substantially spherical opaque quartz bead. Note that the term “opaque” as used herein means that the transmission of heat rays from the semiconductor melt 100 via the liquid sealing material 110 is suppressed (the transmittance of the heat rays is reduced).

  The specific gravity of the opaque quartz beads is preferably configured to be smaller than the specific gravity of the liquid sealing material 110. The particle size of the opaque quartz beads is such that the opaque quartz beads are uniformly dispersed on the surface of the liquid sealing material 110 so as to cover the surface of the liquid sealing material 110 without gaps, and between the liquid sealing material 110 and the opaque quartz beads. For example, the thickness is preferably about several mm so as to be in close contact with each other. Further, the amount of the opaque quartz beads can cover the entire surface of the liquid sealing material 110, and at least the liquid sealing material 110 and the semiconductor melt 100 are covered with the opaque quartz beads when viewed from the upper surface of the crucible 20. It is preferable that the amount is such that the transmission of heat rays from the semiconductor melt 100 through the liquid sealing material 110 can be sufficiently suppressed. For example, the amount of opaque quartz beads is set to an amount that can cover the entire surface of the liquid sealing material 110 with a thickness of about 5 mm, so that the semiconductor melt 100 via the liquid sealing material 110 can be used. The light transmittance in the entire wavelength region can be reduced to 10% or less, and the light transmittance in the visible light region can be reduced to 1% or less. The opaque quartz beads are preferably subjected to high-purity treatment in order to prevent contamination of the semiconductor melt 100 and the liquid sealing material 110. In addition, the thickness of the liquid sealing material 110 that seals the surface of the semiconductor melt 100 is in the range of 5 mm to 20 mm, for example, according to the cross-sectional diameter of the straight body portion 27 of the crucible 20 as in the first embodiment. Are adjusted accordingly.

The irregularities formed on the surface of the opaque quartz beads and the bubbles included in the opaque quartz beads function to reflect or scatter heat rays from the semiconductor melt 100. That is, the opaque quartz beads function to suppress the transmission of heat rays from the semiconductor melt 100 through the liquid sealing material 110, similarly to the beads 120 of the first embodiment. For this reason, the same effects as in the first embodiment can be obtained in this embodiment. Since SiO ₂ constituting the opaque quartz beads reacts with B ₂ O ₃ constituting the liquid sealing material 110, the Si element detached from the opaque quartz beads can be taken into the semiconductor melt 100. . That is, by using opaque quartz beads as the heat ray transmission suppressing material, it is possible to intentionally dope Si elements into the semiconductor crystal.

  In the present embodiment, the heat ray permeation suppression material may be configured as a small piece of aluminum oxide or a molded product, such as alumina beads. The alumina beads function to reflect or scatter heat rays from the semiconductor melt 100. That is, the alumina beads also function to suppress the transmission of heat rays from the semiconductor melt 100 via the liquid sealing material 110, similarly to the beads 120 of the first embodiment.

  In this example, carbon beads 120 were used as the heat ray permeation suppression material, and crystal growth was carried out 20 times continuously.

First, the GaAs seed crystal 30 was accommodated in the narrow diameter portion 25 of the crucible 20 made of pBN (S100). The diameter of the straight body part 27 of the crucible 20 was 160 mm, and the height (length) of the straight body part 27 was 300 mm. Subsequently, 24,000 g of bulk GaAs polycrystal as a main raw material synthesized in advance was placed in the crucible 20 (S105). Furthermore, B ₂ O ₃ as the liquid sealing material 110 and high purity porous graphite beads 120 as the heat ray permeation suppression material were housed in the crucible (S110). The shape of the beads 120 was substantially spherical, and the particle diameter (diameter) was an average φ2 mm, and the surface thereof was coated with glassy carbon. B ₂
The amount of O ₃ was set to 400 g, and the amount of the beads 120 was set to an amount of about 5 mm at the crucible straight body portion 27.

  Next, the crucible 20 is accommodated in the susceptor 50 (S115), the susceptor 50 is mounted on the susceptor support member 55 (S120), the chamber 70 is sealed, and the inside of the crystal growth furnace 1 is replaced with nitrogen gas ( S125), the susceptor support member 55 is rotated, and the rotation of the crucible 20 is started (S130). The rotational speed of the crucible 20 was set to 1 rpm. The heat insulating materials 60 and 62 were formed of a graphite heat insulating material.

  And it energized each of the outer periphery heater units 12a-12d, the heating of the crucible 20 was started (S135), and the semiconductor melt 100 was produced | generated in the crucible 20 (S140). In the process of heating the crucible 20, the pressure in the chamber 70 was controlled so as not to exceed 0.5 MPa. The liquid sealing material 110 softened faster than the GaAs polycrystal melted to form a transparent water tank, and covered the surface of the semiconductor melt 100. The beads 120 floated on the surface of the liquid sealing material 110 as a substantially flat layer having a thickness of about 5 mm.

  Then, the set temperatures of the outer peripheral heater units 12a to 12d are respectively set to 1290 ° C., 1260 ° C., 1120 ° C., and 1050 ° C. (S145), and held for 4 hours until the temperature of the semiconductor melt 100 is stabilized (S150). . In addition, the crucible 20 was arrange | positioned in the height position in which the 1238 degreeC isotherm in the semiconductor melt 100 applied to the upper end part of the seed crystal 30. FIG.

  After the temperature in the crystal growth furnace 1 was stabilized, the crucible 20 was lowered at a speed of 4 mm / h while rotating at a rotation speed of 1 rpm, and a predetermined temperature gradient was formed in the semiconductor melt 100 (S155). Then, when the crucible 20 was lowered about 240 mm over about 2.5 days, the lowering of the crucible 20 was stopped.

  Thereafter, the outer peripheral heater units 12a to 12d are gradually cooled over 24 hours so that each of the outer heater units 12a to 12d becomes 950 ° C, and further, the rate of -20 ° C / h until the temperature of the outer peripheral heater units 12a to 12d reaches 400 ° C, respectively. (S160). Then, the energization of the outer peripheral heater units 12a to 12d was stopped, and the crucible 20 was gradually cooled to room temperature (S165). Thereafter, Step S100 to Step S165 were continuously repeated to produce a total of 20 ingots (GaAs crystals).

  As a result, it was confirmed that all 20 ingots were single-crystallized over the entire length without being polycrystallized.

  Further, one of 20 manufactured ingots is randomly selected, and a plurality of substantially circular wafers having a (100) plane are cut out from the straight body portion of the ingot, and the surface of the wafer is hydroxylated. Etching with a potassium (KOH) melt was performed. For each wafer, the density of pits generated corresponding to dislocations, that is, the density of dislocations was measured.

FIG. 6 is a graph showing the measurement results of the dislocation density according to this example. According to FIG. 6, the average density in the wafer surface of the plurality of cut out wafers was 0.5 × 10 ⁴ cm ⁻² or less over the entire straight body portion of the ingot. Specifically, the length of the straight body portion of the ingot is 250 mm, and the average dislocation density in the wafer plane is 0. 5 mm (near the seed crystal) to 250 mm (near the final solidified portion) of the ingot. 3 × 10 ⁴ cm ⁻² to 0.5 × 10 ⁴ cm ⁻² , and the difference between the minimum value and the maximum value of the average dislocation density in the wafer surface is less than 0.2 × 10 ⁴ cm ⁻² . It was confirmed that there was. Generation of defects such as lineage and crystal subgrain boundaries was not observed over the entire length of the ingot, and it was confirmed that the average dislocation density was not more than a predetermined value.

For the other 19 ingots, the wafer was cut out from the seed crystal side, the middle part of the straight body, and the final solidified part, and the surface of each cut out wafer was subjected to etching treatment with KOH melt, and the above-mentioned dislocation was performed. Density measurements were performed. As a result, it was confirmed that the average dislocation density in the wafer plane was 0.5 × 10 ⁴ cm ⁻² or less in any portion of the remaining 19 ingots. That is, in all 20 ingots produced, no defects such as lineage or crystal sub-boundaries were observed over the entire length of the ingot, and it was confirmed that the average dislocation density was below a predetermined value.

  In this example, crystal growth was performed using the disk 130 as a heat ray transmission suppressing material. The disk 130 used was made of isotropic graphite that had been subjected to high-purity treatment, and had a diameter of 156 mm and a thickness of 3 mm. Other conditions are the same as those in the first embodiment.

  As a result, it was confirmed that the ingot produced according to this example was single-crystallized over the entire length without being polycrystallized.

Further, the dislocation density distribution in the ingot was evaluated by the same method as in Example 1. As a result, the portion having the highest average density in the wafer plane did not exceed 0.6 × 10 ⁴ cm ⁻² , and the ingot Generation of defects such as lineage and crystal subgrain boundaries was not observed over the entire length, and it was confirmed that the average dislocation density was not more than a predetermined value.

  In this example, the liquid sealing material 110 in which the fine powder 140 of high-purity carbon was uniformly dispersed was accommodated in the crucible 20 in step S110. Other conditions are the same as those in the first embodiment. Unlike the embodiment described above, the liquid sealing material 110 that softens and covers the surface of the semiconductor melt 100 is not transparent and has a uniform black and opaque appearance as a whole.

  As a result, it was confirmed that the ingot produced according to this example was single-crystallized over the entire length without being polycrystallized.

Further, when the dislocation density distribution in the ingot was evaluated by the same method as in Example 1, the portion where the average density in the wafer surface was the highest did not exceed 0.5 × 10 ⁴ cm ⁻² , and the ingot Generation of defects such as lineage and crystal subgrain boundaries was not observed over the entire length, and it was confirmed that the average dislocation density was not more than a predetermined value.
(Comparative example)

  In this comparative example, the crystal growth was continuously performed 20 times without using the heat ray permeation suppression material. That is, in step S110, crystal growth was performed without containing the infrared transmission suppressing material in the crucible 20. Other conditions are the same as those in the first embodiment.

  As a result, in this comparative example, it was recognized that the vicinity of the final solidified portion was polycrystallized in 7 ingots out of 20 manufactured ingots.

Further, as a result of measuring the dislocation density distribution of the remaining 13 ingots that were confirmed to be single-crystallized over the entire length, an increase in the dislocation density was observed in the vicinity of the final solidified portion. FIG. 7 shows that one of the remaining 13 ingots that have been confirmed to be single crystallized over the entire length is selected, and a plurality of wafers are cut out from the straight body portion, and the average dislocation density in each wafer surface is determined. It is the result of measurement. The wafer acquisition method and the dislocation density evaluation method are the same as those in the above-described embodiment. As a result, the average dislocation density is 0.5 × 10 ⁴ cm ^{− from} the seed crystal side to the middle part of the straight body part.
^{It was 2} or less, and the dislocation density was almost the same as in the examples. However, it was confirmed that the dislocation density tended to increase rapidly in the vicinity of the final solidified part. That is, in the wafer cut out from the vicinity of the final solidified portion, the average dislocation density in the wafer surface is 8.1 × 10 ⁴ cm ⁻² , and the average dislocation density in the wafer surface cut out from the seed crystal side to the middle part of the straight body portion. It has increased to almost twice as much. In addition, defects called so-called lineage in which dislocations were arranged in a line were observed inside the wafer with increased dislocation density.

<Other Embodiments of the Present Invention>
The heat ray transmission suppressing material according to the present invention has the property of suppressing the transmission of heat rays, that is, the property of absorbing, reflecting, and scattering infrared rays, and the above-described material as long as it does not adversely affect the grown crystal such as impurity contamination. Materials other than those described in the embodiments may be used. For example, when a carbon (C) -doped GaAs crystal is grown, carbon (C) can be intentionally doped by using a material containing carbon as a heat ray transmission suppressing material, and unnecessary contamination. Can be suppressed. In addition, when growing a GaAs crystal doped with silicon (Si), by using a material containing quartz as a heat ray transmission suppressing material, silicon (Si) can be intentionally doped and unnecessary contamination can be caused. Can be suppressed.

  In the above-described embodiment, the crucible 20 is lowered to lower the temperature from the seed crystal side in the semiconductor melt 100 to advance the crystal growth. However, the present invention is not limited to such an embodiment. For example, the above-described crystal growth may be performed by gradually lowering the outer peripheral heater units 12a to 12d at a predetermined speed without lowering the crucible 20. The present invention can also be suitably applied to a furnace body movement method (TF method) in which a furnace body provided with a heater is moved relative to the crucible 20 to perform crystal growth.

  When the semiconductor melt 100 produced | generated in the crucible 20 has dissociation pressure more than atmospheric pressure, the chamber 70 can also be comprised as a pressure vessel. By setting the inside of the chamber 70 to a pressure equal to or higher than the dissociation pressure, it is possible to suppress the evaporation of the semiconductor melt 100 and the evaporation of the raw material components during the crystal growth.

  The entire crucible 20 can be enclosed in an ampoule made of quartz or the like. Then, it is possible to manufacture a semiconductor crystal by installing an ampoule in which the crucible 20 is sealed at a predetermined position in the chamber 70.

The method for producing a semiconductor crystal according to the present invention can be suitably applied not only to producing a single crystal of GaAs but also other III-V group compound semiconductor crystals. For example, InP
, InAs, GaSb, InSb, and other compound semiconductors can be suitably applied. Also suitable for producing a ternary mixed crystal of a III-V group compound semiconductor crystal such as AlGaAs, InGaAs or InGaP or a quaternary mixed crystal of a group III-V compound semiconductor crystal such as AlGaInP. Applicable. Further, the present invention can be suitably applied to the production of II-VI group compound semiconductor crystals such as ZnSe and CdTe.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

It is a section lineblock diagram of the crystal growth furnace which enforces the manufacturing method of the semiconductor crystal concerning a 1st embodiment of the present invention. It is a section schematic diagram near the semiconductor melt surface concerning a 1st embodiment of the present invention. It is the cross-sectional schematic diagram of the semiconductor melt surface vicinity concerning the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram of the semiconductor melt surface vicinity concerning the 3rd Embodiment of this invention. FIG. 3 is a flow diagram illustrating a method for manufacturing a semiconductor crystal according to the first embodiment of the invention. It is a graph which shows the measurement result of the dislocation density of the ingot concerning Example 1. FIG. It is a graph which shows the measurement result of the dislocation density of the ingot concerning a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crystal growth furnace 12a-12d Peripheral heating heater unit 20 Crucible 30 Seed crystal 70 Chamber 100 Semiconductor melt 110 Liquid sealing material 120 Bead (heat ray permeation suppression material)
130 disc (heat ray permeation suppression material)
140 Fine powder (heat ray permeation suppression material)

Claims (6)

In the method of manufacturing a semiconductor crystal, the semiconductor melt is gradually solidified upward from the seed crystal side while contacting the seed crystal disposed at the bottom of the crucible with the semiconductor melt accommodated in the crucible.
A liquid sealing material and a heat ray permeation suppression material are provided on the semiconductor melt,
The liquid sealing material suppresses volatilization of components from within the semiconductor melt,
The method for producing a semiconductor crystal, wherein the heat ray permeation suppressing material suppresses heat ray permeation from the semiconductor melt via the liquid sealing material. Place a seed crystal at the bottom of the crucible,
A semiconductor raw material, a sealing material and a heat ray permeation suppressing material are accommodated in the crucible,
The crucible is heated to produce a semiconductor melt obtained by melting the semiconductor raw material and a liquid sealing material obtained by softening the sealing material in the crucible, whereby the seed crystal and the semiconductor melt are produced. While contacting, providing the liquid sealing material and the heat ray permeation suppression material on the semiconductor melt,
A method for producing a semiconductor crystal, wherein the semiconductor melt is gradually solidified upward from the seed crystal side. The method for manufacturing a semiconductor crystal according to claim 1, wherein the heat ray transmission suppressing material is suspended on the liquid sealing material. The method for producing a semiconductor crystal according to claim 1, wherein the heat ray transmission suppressing material is provided in the liquid sealing material. The method for producing a semiconductor crystal according to claim 1, wherein the heat ray transmission suppressing material is made of a material containing carbon. The method for producing a semiconductor crystal according to claim 1, wherein the heat ray transmission suppressing material is made of a material containing an oxide.

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