JPH1067592A - Horizontal Bridgman crystal growth furnace and semiconductor manufacturing method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To supply granular raw materials into a boat during crystal growth,
A long crystal having a small composition distribution is produced. SOLUTION: On a top surface of a horizontal furnace tube 1, supply holes 6 for granular raw materials 5 are arranged in rows at intervals shorter than the length of a raw material receiving portion 2 a of a boat 2. Even if the boat 2 moves, one supply hole 6 is always located on the raw material receiving portion 2a, so that the granular raw material 5 can be supplied at any time. Further, instead of the supply holes 6 arranged in a line, a circular tube which is held obliquely, accommodates the spherical raw materials 5 in a line, and follows the boat. Projections and steps are provided on the top and bottom of the circular tube, respectively. When stopped at the step, the spherical raw material at the front end is sent out to the end of the circular tube by half rotation of the circular tube and dropped from the opening, and at the same time the next spherical raw material is stopped by the protrusion Thus, one granular raw material is dropped every two half rotations. Further, a partition having a through hole is provided in the boat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a horizontal Bridgman crystal growth furnace capable of replenishing raw materials during crystal production,
And a method for manufacturing a semiconductor manufactured by a horizontal Bridgman crystal growth method.

[0002] The electrical properties of a semiconductor, such as band gap or mobility, are closely related to the lattice constant of the semiconductor. For this reason, in order to manufacture a semiconductor having electrical characteristics suitable for the characteristics of a semiconductor device by an epitaxial growth method, it is necessary that the lattice constant of a substrate crystal can be arbitrarily selected. Such a substrate crystal is realized by a mixed crystal compound semiconductor or a multi-element mixed crystal such as SiGe. However, it is difficult to manufacture a multi-element single crystal with a constant lattice constant.

That is, when a multi-component mixed crystal single crystal containing components having different distribution coefficients is produced by a melt coagulation method, for example, a horizontal Bridgman method, components having a small distribution coefficient are concentrated in a solution as the crystal grows. The manufactured crystal has a composition distribution in the growth direction. in this way. Since the lattice constant of a substrate crystal manufactured from a single crystal having a composition distribution changes based on the composition distribution, the characteristics of an epitaxial semiconductor deposited on the substrate crystal cannot be controlled to a constant value.

[0004] On the other hand, it is known that the composition distribution of such a multi-element mixed crystal single crystal can be made constant by continuing crystal growth while replenishing a part of the raw material composition in the melt. Therefore, there is a need for a horizontal Bridgman crystal growth furnace and a semiconductor manufacturing method that replenish the raw materials during crystal growth to avoid a change in melt composition.

[0005]

2. Description of the Related Art In a melt solidification method for producing a multi-element mixed crystal single crystal by solidifying a melt containing elements having different distribution coefficients, a raw material component depleted in the melt as the crystal grows is supplied. A change in the composition of the melt can be prevented, and a multicomponent mixed crystal single crystal having a constant composition can be produced.

[0006] For example, in the Czochralski method, a method of feeding a granular material during crystal growth, a method of replenishing a melt with a communicating pipe, and a method of replenishing a melt in a crucible outside a double crucible connected by pores. A method for holding the liquid has been devised. In the floating zone method or zone melting method, the front end of a raw material rod having the same composition as that of a multicomponent mixed crystal is melted, and the molten zone is moved to the rear end to produce a multicomponent mixed crystal having a uniform composition. be able to.

However, in the Czochralski method, the floating zone method or the zone melting method, the temperature gradient of the melt is large because the temperature gradient of the melt is large, so that the composition distribution of the produced multi-crystal may be reduced. difficult. Further, there is a disadvantage that the device is complicated and expensive.

The Bridgman method of manufacturing a crystal by holding a melt in a boat moving in a tubular furnace tube and solidifying the melt from one end thereof with the movement of the boat to produce crystals is simple because the fluctuation of the melt temperature is small. There is an advantage that a multi-component crystal having a small composition variation can be manufactured by a simple apparatus, and is often used for manufacturing a mixed crystal system crystal, for example, a compound semiconductor crystal.

[0009] In the Bridgman method, in a vertical Bridgman crystal growth furnace in which a furnace tube is installed vertically, raw materials can be relatively easily supplied from the upper part of the furnace tube.
For example, a device for melting a solid raw material rod inserted from above a furnace and replenishing the melt into a boat is disclosed in Japanese Patent Laid-Open Publication No. Hei 10 (1994).
No. 242480.

On the other hand, in a horizontal Bridgman crystal growth furnace in which a furnace tube is installed horizontally, since a boat moves horizontally in the furnace tube, one supply hole for supplying raw materials is provided on the tube wall of the furnace tube. In this case, the relative position between the supply hole and the boat changes, so that the raw material cannot be charged into the boat.
In a mechanism that inserts raw materials into the furnace core tube from the rear end of the furnace tube, or that provides a raw material introduction path in the furnace core tube and feeds raw materials one by one from the outside, the inside of the furnace by insertion or by the input of raw materials is used. Temperature fluctuations cannot be avoided.
Further, a mechanism for feeding the raw material following the moving boat is complicated, large, and expensive. For this reason, in a horizontal Bridgman crystal growth furnace, a device capable of growing a crystal while supplying a raw material to a melt has not yet been practically used.

[0011]

As described above, in the horizontal Bridgman crystal growing apparatus, since the boat holding the melt moves horizontally in the furnace tube, the boat is replenished with raw materials during the crystal growth. It is difficult. Further, there is a problem that the crystal composition fluctuates due to a temperature fluctuation occurring when the raw material is replenished from the outside.

[0012] The present invention has a raw material supply mechanism having a simple structure for supplying a raw material to a boat moving horizontally in a horizontally installed core tube, and a boat for mitigating heat fluctuation at the time of material supply. It is another object of the present invention to provide a horizontal Bridgman crystal growth furnace having: and a method of manufacturing a semiconductor having a small composition distribution grown by the horizontal Bridgman crystal growth furnace.

[0013]

FIG. 1 is an explanatory view of a first embodiment of the present invention. FIG. 1 (a) shows a longitudinal temperature distribution in a furnace tube, and FIG. 1 (b) and FIG. c) shows the cross section of the horizontal Bridgman crystal growth furnace at the start of crystal growth and at the end of crystal growth, respectively.

FIG. 2 is a sectional view of a second embodiment of the present invention, showing a section of a horizontal Bridgman crystal growth furnace.
FIG. 3 is a sectional view of a circular tube according to the second embodiment of the present invention, showing a structure of a circular tube for replenishing a spherical raw material. In addition,
FIG. 3A shows a circular tube in a rotational position where the protrusion is located upward, and FIG. 3B shows a circular tube in a rotational position where the protrusion is located downward.

FIG. 4 is a sectional view of a boat according to a third embodiment of the present invention, showing a partition wall provided in the boat. 4A shows a longitudinal section, and FIG. 4B shows an AB section shown in FIG. 4A.

Referring to FIG. 1, a horizontal Bridgman crystal growth furnace according to a first configuration of the present invention for solving the above-mentioned problem is arranged such that a horizontally provided furnace tube 1 extends in a longitudinal direction of the furnace tube 1. A melt 2 containing a plurality of elements having different distribution coefficients held in the boat 2 and solidified from the front end of the boat 2 to form a crystal. In a horizontal Bridgman crystal growth furnace that produces
At the rear end of the boat 2, there is provided a raw material receiving portion 2 a into which the granular raw material 5 to be replenished into the melt 3 is dropped, and the granular raw material 5 is introduced into the furnace tube 1 from the outside and dropped therein. A plurality of supply holes 6 are provided in the upper part of the core wall of the core tube 1.
The supply holes 6 are arranged along the longitudinal direction at a shorter interval than the length of the raw material receiving portion 2a, and are located immediately above the raw material receiving portion 2a.
The horizontal Bridgman crystal growth furnace of the second configuration is characterized in that it has a means for dropping the granular raw material 5 from above. 1 is provided with a boat 2 which moves in the longitudinal direction of the furnace tube relative to the furnace tube 1, and a melt 3 containing a plurality of elements having different distribution coefficients held in the boat 2 is supplied to the boat. In a horizontal Bridgman crystal growth furnace for producing crystals by solidifying from the front end of the vessel 2, a raw material receiving, provided at the rear end of the boat 2, into which the spherical raw material 5 a to be replenished into the melt 3 is dropped A part 2a, a circular pipe 11 for accommodating the spherical raw materials 5a in a line in a circular pipe 11 having a front end and a rear end sealed, and an opening 12 for dropping the spherical raw material 5a provided on a peripheral surface of the front end; The opening 12 is located immediately above the raw material receiving portion 2a and the circular pipe Holding means for holding the front end of the circular pipe 11 inclined downward, a rotation mechanism for rotating the circular pipe 11 in one direction or two directions around the axis of the circular pipe 11, and the opening 12 The spherical raw material 5 a-1 is provided on the inner wall surface of the circular tube 11 on the rear end side of the tube 11, is located downward at a first rotational position of the circular tube 11, and has the foremost spherical raw material 5 a-1 at the first rotational position. A step 14 contacting and stopping, and a step between the center of the foremost spherical raw material 5a-1 stopped at the first rotation position and the center of the next spherical raw material 5a-2. The spherical raw material 5a- is provided on the inner wall surface of the circular tube 11 and is located below at the second rotational position of the circular tube 11 and is located next at the second rotational position.
2 is provided with a projection 13 which comes into contact with and stops, and rotates the circular tube 11 from the first rotational position to the second rotational position to remove the most advanced spherical raw material 5a-1 in the circular tube 11. It is sent out to the front end of the circular tube 11, and every time it rotates from the first rotation position to the second rotation position, one spherical raw material 5 is dropped from the opening 12 to the raw material receiving portion 2 a. As a feature, and a third configuration, referring to FIG. 1 and FIG. 2, in the horizontal Bridgman crystal growth furnace of the first or second configuration, the raw material receiving portion 2a is provided with the melt 3 It is characterized by comprising a gentle slope provided at a height above the surface and descending toward the front end of the boat 2, and the fourth configuration is horizontally installed with reference to FIG. A melt 3 containing a plurality of elements having different distribution coefficients in a boat 2 placed in a furnace tube 1
a, 3b is provided at the rear end of the boat 2 in a horizontal Bridgman crystal growth furnace for producing crystals by solidifying the melts 3a, 3b from the front end of the boat 2;
A raw material receiving portion 2a into which granular raw materials to be supplied into the melts 3a and 3b are dropped;
And a through hole 1 provided in the partition wall 15 and connecting the melts 3a and 3b before and after the partition wall 15 with the partition wall 15.
7 and the partition wall 15 from above the melts 3a and 3b.
3b, or partition moving means for moving back and forth in the melts 3a and 3b.
Referring to FIG. 1, a fifth configuration is such that a boat 2 holding a melt 3 containing a plurality of elements having different distribution coefficients is placed inside a horizontally provided core tube 1 so as to extend along the length of the core tube 1. In the direction relative to the furnace tube 1 and solidify from the front end of the boat 2 into a single crystal 9, the rear end of the boat 2 during the production of the single crystal 9. The supply holes 6 arranged in the upper part of the wall of the furnace tube 1 along the longitudinal direction of the furnace tube 1 at shorter intervals than the length of the material receiver 2a are provided in the material receiving portion 2a provided in the portion. It is characterized in that it has a step of dropping the granular raw material 5 from the supply hole 6 located just above the raw material receiving portion 2a, and the sixth configuration is shown in FIG.
Referring to FIG. 3 and FIG. 3, a boat 2 holding a melt 3 containing a plurality of elements having different distribution coefficients is placed inside a horizontally provided core tube 1 in the longitudinal direction of the core tube 1. In the semiconductor manufacturing method, the front end 11a and the rear end 11b are sealed and the spherical raw material 5a is dropped on the peripheral side surface of the front end 11a. The spherical raw material 5a is accommodated in a line in the circular tube 11 provided with the opening 12 to be opened, and then the circular tube 1 holding the front end 11a inclined downward is placed in the circular tube 11 by the opening 1
2 is the raw material receiving portion 2a provided at the rear end of the boat 2.
And a step 14 provided on the inner wall surface of the circular tube 1 on the rear end 11b side of the circular tube 1 from the opening 12 to position the circular tube 11 below. Rotating the spherical raw material 5a around one axis of the circular tube to a first rotational position at which the spherical raw material 5a at the forefront comes into contact with the step 14 and stops; The projection 13 provided on the inner wall surface of the circular pipe 1 between the center of the foremost spherical raw material 5a-1 stopped at the position and the center of the spherical raw material 5a-2 located next thereto is lowered. And rotating around the axis of the circular tube 1 to a second rotational position where the next located spherical raw material 5a-2 abuts on the projection 13 and stops. By rotating from the first rotation position to the second rotation position, the state-of-the-art spherical raw material 5a-1 in the circular tube 1 is removed from the circular tube 1
And the spherical raw material 5a is supplied to the opening 1 each time it rotates from the first rotational position to the second rotational position.
7, and a seventh configuration refers to a boat for holding melts 3a, 3b containing a plurality of elements having different distribution coefficients with reference to FIG. In a method of manufacturing a semiconductor, the melts 3a and 3b are solidified from the front end of the boat 2 to form a single crystal by moving the melts 3a and 3b relative to the furnace core tube placed horizontally. The initial raw material in the boat 2 is melted and the melt 3a,
After the formation of the melts 3a, 3b in the boat 2,
b and the melts 3a, 3a before and after being divided into two.
b, having a through hole 17 connecting the
a) moving into the melts 3a, 3b from above a, 3b or moving back and forth in the melts 3a, 3b, and then moving the inside of the boat 2 including the raw material receiving portion 2a and the raw material receiving portion. 2a
Stopping the partition wall 15 at a position where the partition wall 15 is not divided into front portions, and then supplying the raw material receiving portion 2a with the granular raw material 5 while moving the boat 2 relative to the furnace tube 1. It is characterized by having.

In the first configuration of the present invention, referring to FIG. 1B, one or more rows of supply holes 6 are provided in the upper tube wall of the furnace tube 1 along the longitudinal direction of the furnace tube 1. . Granular raw material is supplied to the supply hole 6 from the outside of the furnace tube 1 when necessary, and the granular material can be dropped into the furnace tube 1 through the supply hole 6. On the other hand, at the rear of the boat 2, a raw material receiving portion 2a for receiving the dropped granular raw material 5 is provided, and the granular raw material 5 dropped to the raw material receiving portion 2a is dissolved in the melt 3,
The necessary melt composition components are supplied to the melt 3. The raw material receiving section 2a may be provided outside the melt 3 as shown in the figure, or may be provided in the melt 3 and directly drop the raw material.

In the first configuration, the interval between the supply holes 6 is shorter than the length of the raw material receiving section 2a. Therefore, even if the boat moves, at least one supply hole 6 is always located immediately above the raw material receiving portion 2a. Therefore, at any time during the crystal growth, it is possible to select the replenishing hole 6 located immediately above the raw material receiving portion 2a and to supply the granular raw material to the raw material receiving portion 2a. That is, the raw material can be supplied to the melt 3 in the boat 2 at any time during the crystal growth. As a result, fluctuations in the melt composition during crystal growth can be suppressed.
Crystals having a small composition distribution can be produced even from a melt containing elements having different distribution coefficients.

The first configuration described above is sufficient by providing a plurality of supply holes 6 in the furnace tube 1 and providing a mechanism for selecting the supply holes 6 into which the granular raw material 5 is dropped, and requires a particularly complicated mechanism. The raw material can be replenished into the boat moving in the horizontal Bridgman crystal growth furnace without performing the above operation.

In the second configuration of the present invention, referring to FIGS. 2 and 3, the raw material to be replenished is a spherical raw material 5a,
The spherical raw materials 5a are housed in a row in a hollow portion of a circular tube 11 having both ends closed. An opening 12 having a size through which the spherical raw material 5a passes is provided on the circumferential side surface of the front end 11a of the circular tube 11. Further, the circular tube 11 is held obliquely with its front end 11a gently inclined downward and its rear end 11b upward. Therefore, the spherical raw material 5a accommodated in the circular tube 11 is
1 Rolling toward the front end 11a of the circular tube 11 except when stopping by contacting the protrusion 13 or the step 14 provided on the inner wall surface, and opening the circular tube 11 to the rotational position where the opening 12 is located below. It is dropped from 12 to the outside of the circular tube 11.

In the present configuration, the circular pipe 11 is provided on the inner wall surface of the circular pipe 11.
Step 1 located below when 1 is placed in the first rotation position
4 and a projection 13 located below when the circular tube 11 is placed in the second rotation position. The step 14 and the projection 13 contact the spherical raw material rolling in the front end direction in the circular tube 11 at the rotational position where they are located below, and stop the rolling of the spherical raw material. That is, referring to FIG. 3 (a), the step 14 is below and the spherical raw material 5 is
In the first rotation position where the spherical raw material 5 stops in contact with the spherical raw material 5, the protrusion 13 is not located below (for example, located above) and does not hinder the rolling of the spherical raw material 5. On the other hand, referring to FIG. 3B, in the second rotation position where the projection 13 is below and the spherical raw material 5 abuts on the projection 13 and stops, the step 14 is not below and the spherical raw material 5 rolls. Do not hinder.

Referring to FIG. 3 (a), the projection 13 is in contact with the center of the frontmost spherical raw material 5a-1 which stops at the first rotational position of the circular tube 11 by contacting the step 14. , At the first rotational position, between the center of the spherical raw material 5a-2 which is positioned second from the foremost end and stopped. Therefore, when the circular pipe 11 is rotated from the first rotation position to the second rotation position, the spherical raw material 5a-2 which is located at the second position from the foremost end and stopped at the first rotation position becomes the second rotation position. At the rotation position, the projections 13 come into contact with the projections 13 and stop, and the spherical raw materials 5a arranged at the rear end therefrom also stop. However, the spherical raw material 5a-1 at the forefront end, which has stopped in contact with the step 14 at the first rotation position, does not contact the projection 13 because it is located at the front end of the circular tube with respect to the projection 13. Roll to the foremost end of the pipe at the position. After that, when the pipe 11 is returned to the first rotation position,
Initially, the spherical raw material 5a-
2 will be located at the forefront end. Therefore, each time the first and second rotational positions are rotated once, the one located at the forefront end among the spherical raw materials 5a arranged in a line is sent out one by one to the front end of the circular tube.

The spherical raw material 5a delivered to the front end of the circular tube 11 as described above is placed at the rotational position of the circular tube 11 where the opening 12 provided on the peripheral side surface of the circular tube 11 is located downward.
, And is discharged out of the circular tube 11 and falls into the core tube 1. The opening 12 does not need to face downward at the first or second rotation position. In this configuration, the opening 12 of the circular tube 11 is always positioned on the raw material receiving portion 2a of the boat 2 so that the circular tube 1
1 is held, the spherical raw material 5 a-1 discharged out of the circular tube 11 through the opening 12 falls into the raw material receiving portion 2 a and is dissolved in the melt 3.

In the second configuration, the raw materials can be introduced one by one into the melt in the boat by rotating around the central axis of the circular pipe (referred to as the circular pipe axis). For this reason, the core tube need only be thick enough to allow a circular tube to be inserted on the boat, and does not require any space for accommodating or moving a special mechanism. Therefore, the furnace tube may be thin, and deterioration of the heat distribution in the furnace caused by making the furnace tube thick can be avoided. Further, the rotating mechanism is much simpler than the mechanism for inserting or flowing the raw material from outside, and operates reliably, so that a highly reliable apparatus can be manufactured at low cost.

In this configuration, the spherical raw materials are accommodated in a line in a circular tube, and most of them are placed in a high-temperature portion in the furnace tube and heated. Therefore, even if this spherical raw material is replenished into the melt, no rapid temperature fluctuation occurs. Further, both ends of the circular tube having this configuration are sealed. For this reason, when the spherical raw material contains an element with a high vapor pressure, the atmosphere in the pipe has a high partial pressure of the element with a high vapor pressure, and the composition change of the spherical raw material due to holding at a high temperature is suppressed. . Therefore, the deterioration of the crystal due to the temperature fluctuation and the change in the composition of the raw material is small, and a good quality crystal is produced.

In the first and second constructions, since the melting point of the raw material to be replenished is generally higher than the temperature of the melt, it does not melt until it is put into the melt. In the third configuration of the present invention, referring to FIGS. 1 and 2, a raw material receiving portion 2a is provided at a rear end of a boat 2 holding a melt 3 at a position higher than the surface of the melt 3. Therefore, the granular raw material 5 such as the spherical raw material 5a is not dropped directly into the melt, but is first dropped into the raw material receiving portion 2a where there is no melt 3, and then rolls on the gentle slope of the raw material receiving portion 2a. To fall. For this reason, when the granular raw material 5 is replenished, the surface of the melt is less ruffled and the crystal quality can be maintained well.

Referring to FIG. 4, the fourth configuration of the present invention includes a partition wall 15 for partitioning the melt 3 in the boat 2 back and forth. The melts 3a and 3b before and after being partitioned by the partition 3 are
The connection is made through a through hole 17 provided in the partition wall 3. The granular raw material 5 is dropped into the melt 3b at the rear or to the raw material receiving portion 2a of the third configuration provided at the rear of the boat 2, and the composition of the melt 3b at the rear is adjusted.

In this configuration, the front melt 3a is separated from the rear melt 3b into which the raw material is charged by the partition wall 15.
For this reason, the waves on the surface of the rear melt 3b generated by the input of the raw material are blocked by the partition walls, and the front melt 3b in contact with the crystal growth interface.
does not propagate to a. In addition, the melt 3b on the rear
Similarly does not propagate to the melt 3a ahead. Therefore, there is little deterioration in crystal quality due to temperature fluctuations and undulations of the melt at the time of material replenishment. Further, the composition of the rear melt 3b changes rapidly at the same time as the introduction of the granular raw material 5, but the front melt 3a in contact with the growth interface gradually mixes with the rear melt through the through-hole 17, so that Little variation in composition.
Therefore, the composition fluctuation of the manufactured crystal is small. In addition, the through holes 17 are used for the melt 3 before and after the supply cycle of the granular material 5.
It is desirable that a and 3b are large enough to be sufficiently mixed. On the other hand, this through hole 17 is so small that the front and back melts do not rapidly become confused as the composition in the front melt fluctuates greatly while the granular raw material is dissolved and sufficiently mixed in the rear melt. Is preferred.

After the raw materials in the boat 2 are melted and before crystal growth starts, it is necessary to make the composition of the entire melt 3 in the boat 2 uniform. The partition 15 described above can be inserted into the melt 3 from above the melt 3 by using partition moving means, for example, the operation rod 16, or can swing back and forth in the melt 3 before and after the boat 2. For this reason, the partition 15 is moved onto the melt 3 until the raw material is melted, and after melting, the partition 15 is inserted into the melt 3 and
By partitioning, the compositions of the melts 3a and 3b before and after the partition can be made uniform. In addition, boat 2 from the beginning
Even if the inside is partitioned by the partition wall 15, after the raw material is melted, the partition wall 1
By moving 5 forward and backward, the front and rear melts 3 a and 3 b can be confused through the through-hole 17 and the melt composition can be made uniform.

The boat according to the fourth configuration can be applied to the horizontal Bridgman crystal growth furnace having the first and second configurations described above. Further, the present invention can be applied to a horizontal Bridgman crystal growth furnace in which a boat is left standing in a furnace tube. When the boat is allowed to stand still, there is no need to follow the movement of the boat with the supply mechanism of the granular material, and the apparatus is simplified.

The fifth configuration of the present invention relates to a method for growing a semiconductor manufactured using an apparatus similar to the horizontal Bridgman crystal growth apparatus according to the first configuration. In this configuration, as in the first configuration, the granular raw material can be replenished without interruption to the raw material receiving section of the boat that moves relative to the furnace core tube inside the furnace tube, so that even long melts with uniform segregation can be used. Can be produced.

The sixth configuration of the present invention relates to a method for growing a semiconductor manufactured using an apparatus similar to the horizontal Bridgman crystal growth apparatus according to the second configuration. In this configuration, similarly to the second configuration, one spherical raw material can be replenished at any time simply by rotating the circular tube so that the opening of the circular tube follows the raw material receiving portion of the boat. Therefore, a uniform and long single crystal can be manufactured by simple means.

The seventh configuration of the present invention relates to a method for growing a semiconductor manufactured using an apparatus similar to the horizontal Bridgman crystal growth apparatus according to the fourth configuration. In this configuration, as in the fourth configuration, the through hole is formed between the melt at the rear end of the boat into which the granular raw material supplied from the raw material receiving section is directly injected and the melt at the front end of the boat where crystals grow. Are connected via
The fluctuation of heat, the fluctuation of solution composition, and the waving of the solution surface at the time of charging the raw material are alleviated, and a single crystal having excellent crystallinity is manufactured.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is directed to a horizontal Bridgman crystal growth reactor having a first configuration and a third configuration,
And a method for manufacturing a semiconductor according to a fifth configuration.

Referring to FIG. 1B, the boat 2 is made of a material that does not react with the melt, for example, pBN (boron nitride having a layer structure manufactured by deposition at a high temperature), carbon or quartz. And a semi-cylindrical portion for holding the melt 3, and a raw material receiving portion 2a whose rear end is slightly inclined upward at the upper end of its rear end. The dimensions of this semi-cylindrical part are, for example,
The length is 0 mm, the length is 100 mm, and the length of the raw material receiving portion 2a is, for example, 20 mm.

The boat 2 is mounted on a carbon susceptor (not shown). The susceptor is connected with a moving means 8, for example, a rod or a wire for towing, and the susceptor on which the boat 2 is mounted moves in the furnace tube 1 in the horizontal direction along the central axis of the furnace tube 1. Note that the boat 2 may be stopped with respect to the floor surface and the core tube 1 may be moved.

The furnace tube 1 is a circular tube having an inner diameter of 50 mm and having both ends opened, and is heated by a heater 10a provided on the outer periphery thereof. The heater 10a is made of, for example, a spiral or cylindrical resistor that is heated by resistance or induction. A heat insulating material 10b is provided outside the heater 1.

At the upper part of the furnace tube 1b, supply holes 6 are provided at equal intervals in a line along the central axis of the furnace tube 1b. The interval between the supply holes 6 is shorter than the material receiving portion 2a, and is, for example, 15 mm. In addition, it is preferable to arrange the interval between the spiral resistors as an integral multiple of the pitch of the spiral heater 10a in order to avoid a decrease in the width of the heater 10a.
The number of the supply holes 6 is, for example, 10, so that the present invention can be applied when the moving distance of the boat is up to 150 mm. Note that the supply holes 6 are not limited to one line, but may be a plurality of lines. The supply hole 6 may be a circular pipe having an inner diameter through which the granular material 5a can pass, for example, a pBN circular pipe having an inner diameter of 3 mm and an outer diameter of 4 mm. Even if the replenishing hole 6 having such a thickness is opened in the furnace tube 1, the change in the temperature distribution in the furnace tube 1 can only be ignored to the extent that the influence on the crystal growth can be ignored.

At the entrance of each of the supply holes 6, a shutter 7a for passing or blocking the granular raw material 5 supplied from the bucket 7 for accommodating the granular raw material 5 is provided.
a replenishing hole 6 at any time by opening and closing a
Can be supplied to

When the atmosphere needs to be set at a high pressure, the above-mentioned furnace tube 1, heater 10a and heat insulating material 10b are used.
, The bucket 7, the supply hole 6, the shutter 7a and the moving means 8e can be held in a high-pressure tank (not shown). At this time, movable parts such as the shutter 7a and the moving means can be operated by a manipulator from outside the high-pressure tank.

The crystal growth is performed according to the following procedure. First,
A seed crystal is fixed to the front end of the sheet 2. As a seed crystal, In
For the production of GaAs crystals, a GaAs single crystal is
Crystals can be produced using Si single crystals. next,
The initial melt raw material is filled in the boat 2. This early fusion
Liquid material is put in a vessel of the same shape as boat 2 before melting
After that, the use of polycrystalline material solidified by rapid cooling
Is preferred to make the uniformity. The melt material is InGaAs
58.0 g of polycrystalline InAs and 40.
0 g of polycrystalline GaAs is used for producing SiGe crystal.
3.3 g of Si polycrystal and 28.7 g of Ge polycrystal were
What was melt-mixed and then quenched and solidified was used. Further
In the case of manufacturing InGaAs crystals, besides the melt raw material,
20 g of B _TwoO_ThreeWas added. This B_TwoO_ThreeIs_,Melting
Form a liquid sealing layer (not shown) that covers the surface of the melt
Ar atmosphere of, for example, 8 atm in a high-pressure atmosphere
In this, evaporation of As having a high vapor pressure is prevented.

Next, the boat 2 containing the seed crystal 4 and the melt raw material is placed in the furnace tube 1 and heated to melt the melt raw material to obtain a melt 3. Referring to FIG. 1A showing the temperature distribution along the central axis in the furnace tube, the temperature in the furnace tube 1 is lower than the crystal growth temperature Tc at the tip of the boat 2 and increases toward the rear end. It has a temperature gradient. In addition, at the rear end of the position exceeding the crystal growth temperature Tc (indicated as “solid-liquid interface position” in the figure), the temperature is higher than Tc throughout the boat in order to prevent the solidification of the melt from starting from a position other than the seed crystal. Is held. The melt 3 in the boat 2 thermally equilibrates with the seed crystal 4 at the crystal growth temperature Tc to form a solid-liquid interface in thermal equilibrium with the seed crystal. The crystal growth temperature Tc is determined from the solid-phase diagram of the melt, and is 1134 ° C. for producing In _0.08 Ga _0.92 As crystal and 1350 ° C. for producing Si _0.9 Ge _0.1 crystal. Of course, in a melt in which an element other than the crystal composition is added as a solvent, the crystal growth temperature Tc for producing a crystal having the same composition is different from this.

After allowing the composition in the melt 3 to homogenize by standing for 12 hours after the temperature rise, the crystal growth is started by moving the boat 2 in the tip direction using the moving means 8. The moving speed is
For example, in the production of InGaAs crystal, 1.00 mm / hour, S
In the production of iGe crystals, it can be 0.6 mm / hour.

In the composition of the melt 3, elements or components having a large distribution coefficient decrease as the crystal grows. For example, InGa
The GaAs component decreases in the As system, and the Si component in the SiGe system.
Decrease. In the present embodiment, the granular material 5 containing more elements or components having a large distribution coefficient than the melt is replenished into the melt 3 at a certain time interval during the crystal growth. Therefore, a change in the composition of the melt accompanying the progress of the crystal growth is suppressed, and the composition fluctuation in the growth direction of the manufactured crystal is reduced.

An element or component having a large distribution coefficient generally has a higher melting point than an element or component having a small distribution coefficient.
Even if the supply hole 6 is higher than the crystal growth temperature Tc, the granular raw material 5 passes as it is in a granular state, and does not melt in the supply hole 6 and stay in the supply hole 6. Therefore, even if the supply hole 6 is thin, the granular raw material 5 can be surely dropped onto the raw material receiving portion 2a of the boat 2.

The interval at which the granular material 5 is supplied to the melt 3 is as follows.
It is determined as follows. Although a two-component system will be described for simplicity, the same applies to a system with three or more components.

The compositions of the melt 3, the crystal 9 grown from the melt 3 and the granular raw material 5 were Ax _m B ₁ -x _m and Ax
_s B _1- x _s, and Ax _h B _1- x _h. Here, A and B each represent one element or one component of a mixed crystal system (hereinafter, simply referred to as “component A” and “component B”). Also,
x _m , x _s and x _h represent the composition ratio (molar ratio) of A of the melt 3, the crystal and the granular raw material 5, respectively. At this _time, the weight W ^m _A component A contained in the melt 3 in the weight W _{m ^{is, W m A = W m (}} w A x m / M m) (1) weight W _s of the crystal 9 weight W ^s of the component a contained in _{a ^{is, W s a = W s (}} w a x s / M s) (2) the weight W by weight of components a contained in the granular crystals 5 of _h W ^h _a
Is a ^{_{W h A = W h (w}} A x h / M h) (3). Here, w _A represents the weight per mole of component A. Further, M _m , M _s , and M _h represent the weight of each of the melt 3, the crystal 9 and the granular raw material 5 per chemical equivalent, and when the weight per mole of the component B is w _B , M _m = w _{A x m + w b (1} -x m) (4) M s = w A x s + w b (1-x s) (5) M h = w A x h + w b (1-x h) (6) It is.

Next, at time t, the composition A is weighed W ^s _A (t).
From the melt with the weight W _m (t) containing
Consider a case where a crystal 9 of t grows and a granular raw material of ZΔt is supplied during the growth. In this case, the weight W _m (t + Δt) of the melt after the time Δt is determined in consideration of the weight CΔt that decreases due to crystallization and the weight ZΔt that increases when replenished, and W _m (t + Δt) = W _m (t) −CΔt + ZΔt (7) On the other hand, the weight W ^m _A (t + Δt) of component A in the melt after Delta] t time, the components in the melt at time t A
Weight W ^s _A and weight W of component A, which are reduced from the melt by the crystal growth of weight W _s = CΔt to weight W ^m _A (t) of
and Koryo weight W ^h _A of component A to increase the supply of the granular raw material for _h = _ZΔt, represented as _{^{W m A (t + Δt)}} = W m A (t) -W s A + W h A (8) . Here, W ^m _A (t), W ^s _A , and W ^h _A are represented by W _m = W _m (t) and W _{s in} Equations 1 to 3, respectively.
= CΔt, W _h = ZΔt.

By modifying the equation 1, the composition ratio x _m of the component A becomes
The composition ratio at time t, x _m (t), x _m (t) = (W ^m _A (t) M _m (t)) / (W _m (t) w _A ) (9) The composition ratio _{x m (t + Δt),} x m (t + Δt) = (W m A (t + Δt) M m (t + Δt)) is changed to _{/ (W m (t + Δt} ) w A) (10). Here, the quantities with the variables (t) and (t + Δt) represent values at times t and t + Δt, respectively.

In this embodiment, the replenishment rate Z of the granular raw material is determined so that the composition ratio of the melt does not change. Therefore, Equation 9
In equation (10), the composition ratio x _m of the component A in the melt and the weight M _m per chemical equivalent of the melt do not change.
_m (t) = x _m (t + Δt) and M _m (t) = M _m (t
+ Δt). As a result, from Equations 9 and 10, represented as _{^{W m A (t) / W}} m (t) = W m A (t + Δt) / W m (t + Δt) (11).

By substituting Equations 7 and 8 into Equation 11 and solving for Z in consideration of Equations 1 to 6 and W _s = CΔt and W _h = ZΔt, Z = C (M _h / M _s ) ( x _m −x _s ) / (x _m −x _h ) (12) Here, the crystal growth rate C is obtained by using the moving speed v of the solid-liquid interface, the area S of the solid-liquid interface, and the density ρ of the crystal.
Calculated as C = Svρ.

Under the conditions exemplified in the first embodiment described above, when producing In _0.08 Ga _0.92 As crystals, 1 g of spherical raw material 5 composed of spherical GaAs is supplied one by one every 42 minutes and 45 seconds. When producing Si _0.9 Ge _0.1 crystals, the replenishment rate Z of the granular material is 0.13216 g.
/ Hour, for example, one granular material 5 composed of Si spheres having a diameter of 2 mm is replenished every 4 minutes and 30 seconds.

The Si _0.9 exemplified in the first embodiment described above.
In the production of the Ge _0.1 crystal, the granular raw material composed of Si and the granular raw material composed of Ge can be supplied at mutually independent time intervals. Under the exemplary conditions described above, from Equation 12, 0.5778 g / h of Si and 0.27928 of Ge
By replenishing at g / hr, the composition of the melt is kept constant. Such a replenishing speed can be realized by replenishing one granular raw material 5 composed of Si spheres having a diameter of 2 mm every one minute and replenishing one granular raw material 5 composed of Ge spheres having a diameter of 2 mm every 4 minutes and 48 seconds. it can.

The second embodiment of the present invention relates to the second, third, and sixth configurations of the present invention. In the second embodiment, the composition and amount, growth conditions, and crystal composition of the furnace tube, boat, and melt are the same as those in the first embodiment, and the means for replenishing the granular material is different.

In the second embodiment, referring to FIG. 2 and FIG. 3, a spherical raw material 5 having a diameter of, for example, 2 mm is provided on a peripheral side surface of a front end portion of a pBN circular pipe 11 having an inner diameter of, for example, 3.5 mm.
An opening 12 having a size through which a can pass is provided. Further, a projection 13 projecting, for example, 1 mm from the inner wall surface is provided on the side surface of the circular tube 11 on the rear end 11b side of the opening 11. Such protrusions 13
For example, it is formed by inserting a pin from the outer wall of the circular tube 11. The shape of the other protrusions 13 can be formed by inserting a spiral protrusion, for example, a spirally formed pBN into the circular tube 11.

Next, the spherical raw material 5a is transferred to the circular tube 11 at the rear end 11 thereof.
b, and the rear end 11b of the circular tube 11 is sealed with a stopper or a lid. Next, referring to FIGS. 2 and 3 (a), the circular tube 11 is held by a holding mechanism (not shown) so that the opening 12 faces upward and the rear end 11b faces upward. At this time, the spherical raw material 5
a is a circular tube 11 in which the foremost spherical raw material 5a-1 is sealed.
Then, the spherical raw materials 5a-2 and 5a come into contact with each other and stop in contact with the step 14 formed from the front end. The step 14 may be provided on the rear end side of the opening 12, or a spiral projection may be used as a combination of the step 14 and the projection 13.

Referring to FIG. 2, the circular tube 11 has an opening 1 just above the raw material receiving portion 2a of the boat 2 placed in the core tube 1.
The boat 2 moves together with the boat 2 so that the boat 2 is located. When the boat 2 is stopped relative to the floor and the core tube 1 is moved, the circular tube 11 also stops relative to the floor. The movement of the circular tube 11 is performed by a holding mechanism. This holding mechanism holds the rear end of the circular tube 11 protruding to the rear end side of the core tube 11, moves the circular tube 11 parallel to the central axis of the core tube, and rotates the circular tube 11 around the central axis. I do.

To drop the spherical raw material 5a into the raw material receiving portion 2a, referring to FIG. 3 (b), the circular pipe 11 is rotated half a turn so that the opening 12 is directed downward. As a result, the foremost spherical raw material 5a-1 drops through the opening 12, and is dropped into the raw material receiving portion 2a immediately below. The second spherical raw material 5 from the front end
a-2 comes into contact with the projection 13 and stops, and becomes the foremost spherical material thereafter. Therefore, when the circular tube 11 is returned to the rotational position where the opening 12 faces upward again, referring to FIG.
The state returns to the state where the spherical raw material 5a is reduced by one from the initial state. In this manner, by performing the half rotation of the circular tube 11 twice, one spherical raw material 5a is put into the boat 2.

The third embodiment of the present invention relates to a horizontal Bridgman crystal growth furnace provided with a boat 2 having partition walls, and a method of manufacturing a semiconductor according to a seventh configuration. Referring to FIG. 4, the boat of this embodiment has a plate-shaped partition wall 15 for dividing the melt 3 in the boat 2 back and forth. At the time of crystal growth, the crystal is separated from the melt 3 by the partition wall 15.
Grow from a. On the other hand, the granular material 5 is supplied to the rear melt 3b directly or via the material receiving part 2a.

Referring to FIG. 4 (b), the partition 15 is formed of a semi-circular plate which is in close contact with the inner surface of the boat 2, and is formed by horizontally cutting the lower end 5mm of the semi-circular plate. This cut portion forms a through hole 17 connecting the front and rear melts 3a and 3b.

At the center of the disk of the semi-disk-shaped partition 15,
An operation rod 16 held substantially parallel to the center line of the furnace tube is fixed. The partition wall 15 can be moved back and forth by moving the operation rod back and forth, or can be moved onto the melt 3 by rotating the operation rod. That is, the operation rod 16 is slightly tilted to
Is moved away from the boat 2 wall, and then moved back and forth. Alternatively, the operating rod 16 is slightly tilted to separate the partition 15 from the wall surface of the boat 2, and then the operating rod 16 is rotated to rotate the semi-disk-shaped partition 15 by 180 degrees about the center axis of the disk. It rotates above the melt 3. By operating the partition 15, the melts 3a and 3b in the boat can be sufficiently stirred or mixed. This operation of the partition wall 15 is performed before the start of crystal growth in order to mix the incompletely mixed melt 3 immediately after the raw material is melted. In this case, the raw material may be melted in a state where the partition walls 15 have been moved onto the melt 3 in advance, and after melting, the melt may be left for a sufficient time for mixing, for example, 12 hours, and then moved into the melt 3 to start crystal growth. After the partition 15 is moved into the melt 3, it is preferable to leave the partition 15 for about one hour, for example, to stabilize the temperature. Of course, the movement of the partition wall 15 back and forth and the movement on the melt can also be mixed. Since the operating rod is thin, it does not have a problematic effect on the temperature distribution in the core tube. The operating rod is operated from the outside of a high-pressure tank that hermetically accommodates the entire growth furnace. The partition wall 15 can be manufactured using a material that does not react with the melt 3, for example, pBN, carbon, quartz, or the like.

FIG. 5 is a view for explaining the effect of the present invention, and shows In _0.08 Ga _0.92 A manufactured according to the first to third embodiments.
3 shows a composition distribution of an s crystal. The amount of In in the crystal was measured using an electron microprobe analyzer (EPMA).
Was measured by

A in FIG. 5 shows In which the melt is solidified from the tip of the boat without replenishing the conventional granular raw material.
₄ shows the composition distribution of a _0.08 Ga _0.92 As crystal. Although the target In composition ratio is 0.08 in the initial stage of growth, the In composition ratio increases with crystal growth, and when the crystal length exceeds 3 mm, the In composition ratio exceeds 0.09. Therefore, only short crystals having a uniform composition can be produced.

FIG. 5B shows the composition distribution of the In _0.08 Ga _0.92 As crystal produced according to the first and second embodiments. In these example embodiments, the granular raw material is replenished during crystal growth into a boat without barriers. In the present embodiment, after the In composition ratio reaches 0.09 when the crystal length is 3 mm, the In concentration in the melt decreases due to the replenishment of the granular material, so that the In composition ratio in the crystal rapidly decreases. ing.
Thereafter, the In composition ratio increases again, and the same process is repeated thereafter. Therefore, even with a long InGaAs crystal of 5 cm, the In composition ratio could be suppressed to within 0.08 ± 0.01.

FIG. 5C shows the composition distribution of the In _0.08 Ga _0.92 As crystal manufactured using the boat having the partition walls of the third embodiment in the first and second embodiments. When the boat of this embodiment is used, the variation of the In composition ratio is suppressed to within 0.08 ± 0.003 over the entire crystal length of 5 cm. Thus, in the third embodiment, the fluctuation range of the crystal composition is smaller than in the first and second embodiments. This is presumed to be a reservoir in which the melt at the rear of the partition, whose composition changes rapidly due to the replenishment of the granular material, slowly mixes with the melt at the front of the partition through the through hole, which directly contacts the crystal growth interface in the third embodiment. . Further, in the crystal manufactured according to the third embodiment, growth fringes are hardly observed, and it is clear that the influence of the rapid temperature fluctuation is small even when the granular raw material is supplied.

The fourth embodiment of the present invention relates to a horizontal Bridgman crystal growth furnace for growing a crystal while resting a boat in a furnace tube. The boat used in this embodiment is the same as the boat of the third embodiment having a partition. The melt and the crystal composition are the same as those of Si _0,9 Ge _0.1 described in the first embodiment.
This is the same as the production example of the crystal. Referring to FIG. 1 _, the horizontal Bridgman crystal growth furnace of this embodiment includes one supply hole 6 having the same structure as that of the first embodiment. Granular raw material 5
Passes through the supply hole 6 and falls into the raw material receiving section 2a.

In this embodiment, the temperature of the solid-liquid interface is 13
The temperature gradient at the solid-liquid interface was 50 ° C. The temperature inside the furnace tube was lowered at a rate of 3 ° C./hour, and spherical raw materials made of Si having a diameter of 2 mm were dropped one by one every 4 minutes and 30 seconds. As a result, a crystal having a length of 8 cm without cracks was obtained.

[0068]

According to the present invention, the granular raw material is stored in a boat moving relatively in the core tube of the horizontal Bridgman crystal growth furnace relative to the core tube without disturbing the temperature distribution in the core tube using a simple mechanism. Can be replenished. In addition, fluctuations in the composition and temperature of the melt due to replenishment of the granular material can be mitigated by the partition for separating the melt. Therefore, it is possible to provide a horizontal Bridgman crystal growth furnace capable of growing a long crystal having a small composition change and a multi-element semiconductor having a small composition fluctuation, and to improve the performance of semiconductor devices and electronic equipment using the crystal. It greatly contributes to

[Brief description of the drawings]

FIG. 1 is a sectional explanatory view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment of the present invention.

FIG. 3 is a sectional view of a circular tube according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a boat according to a third embodiment of the present invention.

FIG. 5 is a diagram for explaining the effects of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace tube 1a Front end 1b Rear end 2 Boat 2a Raw material receiving part 3 Melt 4 Seed crystal 5 Granular raw material 5a Spherical raw material 6 Supply hole 7a Shutter 7 Bucket 8 Moving means 9 Crystal 10a Heater 10b Heat insulating material 11 Circular tube 12 Opening 13 Projection 14 Step 15 Partition wall 16 Operation rod 17 Through hole

Claims (7)

[Claims] A boat is provided which moves in a furnace tube provided horizontally with respect to the furnace tube in a longitudinal direction of the furnace tube, and a plurality of elements having different distribution coefficients retained in the boat are provided. In a horizontal Bridgman crystal growth furnace for producing crystals by solidifying the melt containing the melt from the front end of the boat, a raw material receiving portion into which the granular raw material to be supplied into the melt is dropped is provided at the rear end of the boat. A plurality of supply holes for introducing and dropping the granular raw material from the outside to the inside of the furnace tube are provided at the upper part of the tube wall of the furnace tube along the longitudinal direction of the furnace tube so as to extend from the length of the material receiving portion. A horizontal Bridgman crystal growth furnace comprising means arranged at short intervals and for dropping said granular raw material from said supply hole located immediately above said raw material receiving portion. 2. A boat moving horizontally in a furnace tube provided in a horizontal direction relative to the furnace tube in a longitudinal direction of the furnace tube, wherein a plurality of elements having different distribution coefficients held in the boat are removed. In a horizontal Bridgman crystal growth furnace for producing crystals by solidifying the melt containing the melt from the front end of the boat, a spherical raw material provided at the rear end of the boat and to be supplied to the melt is dropped. A raw material receiving portion, and a circular pipe having a front end and a rear end sealed therein and having an opening for dropping the spherical raw material on a peripheral side surface of the front end, the circular pipe accommodating the spherical raw materials in a line,
Holding means for holding the circular pipe with the opening positioned immediately above the raw material receiving portion and holding the front end of the circular pipe at a downward inclination, and rotating the circular pipe in one direction or two directions around the circular pipe axis. A rotating mechanism to be provided on the inner wall surface of the circular tube at the rear end side of the circular tube with respect to the opening, and positioned at a first rotational position of the circular tube at a lower position, and at a first rotational position of the foremost end thereof. The step where the spherical raw material comes into contact and stops, and the inner wall surface of the circular pipe between the center of the frontmost spherical raw material stopped at the first rotation position and the center of the next spherical raw material A projection which is provided at a second rotation position of the circular tube at a lower position, and at which the spherical material located next at the second rotational position abuts and stops. From the first rotation position to the second rotation position to deliver the most advanced spherical raw material in the circular tube to the front end of the circular tube, and from the first rotation position to the second rotation position. Horizontal Bridgman crystal growth furnace, characterized by dropping the raw material receiving portion to one of the spherical material from the opening in each rotation to second rotary position. 3. The horizontal Bridgman crystal growth furnace according to claim 1, wherein the raw material receiving portion is provided at a position higher than the surface of the melt, and has a gentle slope descending toward a front end of the boat. A horizontal Bridgman crystal growth furnace. 4. A crystal is produced by holding a melt containing a plurality of elements having different distribution coefficients in a boat placed in a horizontally installed core tube and solidifying the melt from the front end of the boat. In a horizontal Bridgman crystal growth furnace, a raw material receiving portion provided at the rear end of the boat and into which the granular raw material to be supplied into the melt is dropped, and a rear portion including the raw material receiving portion inside the boat And a partition wall provided in the partition wall not including the raw material receiving portion, a through hole provided in the partition wall and connecting the melt before and after being partitioned by the partition wall, and a partition wall formed in the melt from above the melt. A horizontal Bridgman crystal growth furnace comprising: 5. A boat holding a melt containing a plurality of elements having different distribution coefficients is moved in a horizontally provided core tube relative to the core tube in the longitudinal direction of the core tube,
In a method of manufacturing a semiconductor which is solidified from a front end of the boat to form a single crystal, a semiconductor device is provided at a raw material receiving portion provided at a rear end of the boat during production of the single crystal, at a top of a tube wall of the core tube. A semiconductor having a step of dropping a granular raw material from a supply hole located immediately above the raw material receiving portion among supply holes arranged in a line at a shorter interval than the length of the raw material receiving portion along the longitudinal direction of the furnace tube. Manufacturing method. 6. A boat holding a melt containing a plurality of elements having different distribution coefficients is moved in a horizontally provided core tube in a longitudinal direction of the core tube relative to the core tube,
In a method of manufacturing a semiconductor which is solidified from a front end of the boat to form a single crystal, the spherical raw material is placed in a circular pipe having a front end and a rear end sealed and an opening provided on a peripheral side surface of the front end for dropping the spherical raw material. Holding in a line, and then holding the circular tube, whose front end is inclined downward, so that the opening is located directly above the raw material receiving portion provided at the rear end of the boat. A step provided on the inner wall surface of the circular tube on the rear end side of the circular tube from the opening is located below, and the spherical raw material at the foremost end comes into contact with the step and stops. Rotating around the axis of the circular tube to a first rotational position, and then positioning the circular tube at the center of the frontmost spherical raw material stopped at the first rotational position and at the position next to the center. A projection provided on the inner wall surface of the circular tube between the center of the spherical raw material is located below, and is located next to the projection. Rotating the circular tube from the first rotational position to the second rotational position until the raw material comes into contact with the projections and stops around the circular tube axis to a second rotational position where the raw material stops. Then, the most advanced spherical raw material in the circular tube is sent to the front end of the circular tube, and each time the spherical raw material rotates from the first rotational position to the second rotational position, one spherical raw material is discharged from the opening through the opening. A method for manufacturing a semiconductor, comprising: dropping a material into a raw material receiving unit. 7. A boat holding a melt containing a plurality of elements having different distribution coefficients is moved in a horizontally installed core tube relative to the core tube, and the melt is moved to the front end of the boat. In the method for manufacturing a semiconductor which is solidified from a portion to form a single crystal, after the initial raw material in the boat is melted and the melt is formed, the melt in the boat is divided into two parts by forward and backward and two minutes Moving a partition having a through-hole connecting the melt before and after the melt from the melt into the melt or moving the melt back and forth, and then receiving the raw material in the boat. Stopping the partition wall at a position separating a rear portion including a portion and a front portion not including the raw material receiving portion, and then moving the boat relative to the furnace tube while adding the granular raw material to the raw material receiving portion. And a replenishing step.