JPH0891982A - Apparatus for producing single crystal and method therefor - Google Patents

Abstract

PURPOSE: To provide an apparatus for producing a single crystal having a high pulling up fraction non-defective of the single crystal and a method therefor. CONSTITUTION: This apparatus for producing a single crystal is obtained by installing a heat shielding unit 20, hangable to the upper part of a crucible 2 and shielding the pulled up single crystal 32 from the exposure to heat of a heater 3 and a bottomless cylindrical partition wall 23, hung to the lower part of the heat shielding unit 20, forming a double crucible together with the crucible when lowered and placed in the crucible 2 and isolating a region 8 of a raw material melt for growing the single crystal from a region 9 of a granular raw material in the apparatus for producing the single crystal capable of feeding the granular raw material 30 into the crucible 2 in a chamber 1 capable of being evacuated, heating the outside of the crucible 2 with the heater 3, producing the raw material melt 31, newly supplying the granular raw material to the crucible and pulling up the single crystal 32 from the raw material melt 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for producing a single crystal, and more particularly to an apparatus and method for producing a single crystal such as Si single crystal using a double crucible.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a granular raw material is put into a quartz pot 2 inside a chamber 1 capable of vacuuming.
In a method for producing a single crystal in which a crucible 2 is heated by a heater 3 and a granular raw material is melted in a raw material melt to pull up a single crystal 4, an integral double type in which a cylindrical quartz partition wall 5 is fixedly arranged inside the crucible 2. A quartz crucible 2 having a structure is used.

Above the raw material melt in the quartz crucible 2, a single crystal seed 4 is pulled by a seed chuck 4a.
A radiant heat shielding cylinder 6 is provided to prevent the radiant heat from the heater 3 from being applied to the single crystal growing below (Japanese Patent Laid-Open Nos. 62-278188 and 62-24188).
9, JP-A-63-233092, JP-A-64-7699
2, JP-A-64-83592, JP-A-64-8359
3, JP-A-1-275495, etc.).

In the inner crucible 8 which is the portion inside the quartz partition wall 5 in the quartz crucible 2, a granular raw material is initially piled up, but the piled granular raw material is melted by the heater 3 and the raw material melt is melted. To be

Further, in the outer crucible 9 which is an outer portion of the quartz partition wall 5 in the quartz crucible 2, a granular raw material supply pipe 10 is provided.
The granular raw material is newly replenished from.

[0006]

Conventionally, since the radiant heat shielding tube 6 is attached above the quartz crucible 2 having an integral double structure, the radiant heat shielding tube is placed on the granular raw material which is initially charged into the crucible 2 and piled up. In order to prevent 6 from touching,
In the melting step of the granular raw material, the quartz crucible 2 and the heater 3
Need to be placed much lower than.

Therefore, in order to maintain the temperature of the bottom of the quartz crucible 2 at the melting temperature, the power of the heater 3 must be increased. As a result, the following drawbacks exist.
(1) The time required to dissolve the granular raw material becomes very long, and the inside of the chamber 1 is contaminated to that extent, for example, about twice as much as in the ordinary CZ method. (2) The temperature above the quartz crucible 2 becomes abnormally high, the upper portion 5a of the cylindrical quartz partition wall 5 is softened and deformed, the pulling condition of the crystal is deteriorated, and the yield rate of the single crystal is, for example, normal. CZ method 5
It significantly decreases to 0%.

On the other hand, a method of arranging an auxiliary heater below the bottom of the quartz crucible 2 has been proposed (for example, Japanese Patent Laid-Open No. 1-275495), but the heater structure becomes complicated.

Therefore, an object of the present invention is to solve the above problems of the prior art and to provide an apparatus and method for producing a single crystal having a high yield rate of single crystals.

[0010]

In order to achieve the above object, the apparatus for producing a single crystal according to the present invention supplies granular raw material to a crucible in a chamber capable of vacuuming, and heats the outside of the crucible with a heater. Then, in the single crystal manufacturing apparatus that generates a raw material melt and replenishes the crucible with a new granular raw material and pulls a single crystal from the raw material melt, it can be lifted and lowered and can be hung above the crucible. A heat shield that shields the single crystal from being irradiated with the heat of the heater, and a double crucible together with the crucible when suspended in the lower part of the heat shield and lowered and placed in the crucible. It is characterized by comprising a bottomless cylindrical partition wall that separates the region of the raw material melt for forming and growing the single crystal from the region of the granular raw material.

It is preferable that the bottomless cylindrical partition wall can be detachably hung on the heat shield.

Further, it is preferable that the heat shield can be connected to a suspending wire for pulling the single crystal.

In the method for producing a single crystal according to the present invention, the granular raw material is supplied to the crucible in the chamber which can be evacuated,
The outside of the crucible is heated by a heater to generate a raw material melt,
In the single crystal manufacturing method of newly supplying a granular raw material to the crucible and pulling a single crystal from the raw material melt, a heat shield for shielding the irradiation of heat of the heater to the pulled single crystal of the crucible A region of a raw material melt and a region of a granular raw material for forming a single crystal by forming a double crucible together with the crucible when it is lowered and placed in the crucible while being suspended above. A bottomless cylindrical partition wall that isolates from each other is suspended, the heat shield and the bottomless cylindrical partition wall are pulled up above the crucible, and a granular raw material is supplied into the crucible, and the crucible is heated by the heater. The outside is heated to dissolve the granular raw material, and the heat shield and the bottomless tubular partition are pulled down until the bottom of the bottomless tubular partition reaches the bottom of the crucible, and the double crucible together with the crucible. To Form, characterized in that pulling a single crystal from the area of the raw material melt.

[0014]

The granular material is fed into the crucible with the heat shield and the bottomless cylindrical partition being pulled up above the crucible. Even if the granular raw material is piled up in the crucible, the thermal shield does not come into contact with the granular raw material because it is pulled up above the crucible. The outside of the crucible is heated by a heater to melt the granular raw material, and even if there is a pile of granular raw materials, they are melted to form a raw material melt. After this, pull down the heat shield and the bottomless cylindrical partition wall,
The bottomless cylindrical partition is placed in the crucible, the bottomless cylindrical partition is removed from the heat shield, and a double crucible is formed together with the crucible. Even if there is a pile of granular raw materials at the beginning, since the granular raw materials have already been melted, the heat shield can be arranged at a predetermined position that shields the heat of the single crystal to be pulled.

[0015]

Embodiments of a single crystal production apparatus according to the present invention will be described below with reference to the drawings. Chamber 1 capable of vacuuming
A carbon crucible 12 is attached inside the crucible shaft 11, and a quartz crucible 2 is arranged inside the carbon crucible 12. A carbon heater 3 is arranged outside the carbon crucible 12, and a heat retaining member 13 is arranged outside the carbon heater 3.

A carbon cylindrical heat shield 20 is suspended above the quartz crucible 2 by a suspension member 21. A cylindrical quartz partition wall 23 is suspended below the heat shield 20 by a plurality of hook pins 22.

FIG. 2 shows the heat shield 20, the suspension member 21 and the quartz partition wall 23 in detail. The upper portion of the heat shield 20 has a flat flange shape, and a plurality of hook pins 22 made of molybdenum or quartz are attached to the lower portion of the flange portion 20a. Three molybdenum columns 21b are fixed to the upper part of the flange-shaped portion 20a by carbon bolts 21a, and the upper ends of the molybdenum columns 21b are horizontally connected to each other by a molybdenum member 21c. At both ends of the molybdenum member 21c, hook pins 21d for hooking the hanging wire are provided. The pin 21e is hooked on the hook pin 21d. The pin 21e is branched from the upper part of the seed chuck 4a.

The quartz partition wall 23 as a bottomless cylindrical partition wall is
It has a hollow cylindrical shape. A hook 23 on which the end of the hook pin 22 is hooked is attached to the upper part of the quartz partition wall 23.
a is provided. A hole 23b having a diameter of about 10 mm is formed on the side of the quartz partition wall 23 for moving the raw material melt generated in the outer crucible 9 into the inner crucible 8. Here, the inner crucible 8 is a region of the raw material melt for growing a single crystal of the double crucible, and the outer crucible 9 is a region of the double crucible to which the granular raw material is replenished.

Next, the operation of this embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 shows a state before the double crucible is formed. The single crystal 4 is attached to the seed chuck 4a. A suspension member 21 is suspended on a suspension wire 4b on which the seed seed chuck 4a is suspended via a pin 21e, and a suspension pin 22 is provided on a heat shield 20 fixed to the suspension member 21. A quartz partition wall 23 is suspended via the. A predetermined amount of granular raw material is piled up in the quartz crucible 2. In this state,
The chamber 1 is closed, the inside of the chamber 1 is kept under a reduced pressure of about 15 Torr in an argon gas atmosphere, and the heater 3 is energized.

After the piled up granular raw material is heated by the heater 3 and melted in the raw material melt 31, the suspension wire 4b descends. When the bottom end of the quartz partition wall 23 comes into contact with the bottom of the quartz crucible 2 and the hanging wire 4b is further lowered slightly, the catch pin 22 is disengaged, and the quartz partition wall 23 is placed on the bottom portion of the quartz crucible 2. , A double crucible is formed. After that, when the suspending wire 4b is further lowered slightly, the flange-shaped portion 2 of the heat shield 20 is
0a comes into contact with the stopper 25 disposed above the heat retaining member 13, the pin 21e is disengaged, and the heat shield 20 is disposed at a predetermined position. By adjusting the height of the stopper 25, the height position of the heat shield 20 can be adjusted.

FIG. 4 shows a state in which the quartz crucible 2 and the quartz partition wall 23 form a double crucible. Granular raw material input pipe 1
The granular raw material is replenished from 0 to the outer pot 9. The single crystal 31 grows below the seed 4 and the single crystal 31 is pulled up.

According to the configuration of this embodiment, the heat shield 20 and the bottomless cylindrical partition wall 23 can be suspended above the quartz crucible 2, so that the granular raw material 30 is initially supplied into the quartz crucible 2. In the process and the process of heating the granular raw material 30 with the heater 3 to melt it, the heat shield 20 and the bottomless cylindrical partition wall 2
3 can be arranged at a different position with respect to the position of the quartz crucible.

As a result, in the step of melting the granular raw material 30, the position of the double crucible constituted by the quartz crucible 2 and the bottomless cylindrical partition wall 23 should be selected at a position where the heat of the heater 3 can be sufficiently obtained. Will be possible. Then, it is not necessary to increase the power of the heater 3, it is possible to prevent the time required for melting the granular raw material 30 from being very long, and it is possible to prevent the inside of the chamber 1 from being contaminated. Further, it is possible to prevent the temperature above the quartz crucible 2 from becoming abnormally high.

Since the quartz partition wall 23 can be detachably suspended from the heat shield 20, the quartz partition wall 23 can be separated from the heat shield 20 to form a so-called double crucible.

Since the heat shield 20 can be connected to the suspending wire 4b for pulling up the single crystal 32, the heat shield 20 can be moved up and down with a simple structure.

[0026]

As described above, according to the structure of the present invention, the heat shield and the bottomless cylindrical partition can be hung above the quartz crucible, so that the granular raw material is placed in the quartz crucible. In the step of initially supplying and the step of heating and melting the granular raw material with a heater, the heat shield and the bottomless cylindrical partition can be arranged at different positions suitable for each step with respect to the position of the quartz crucible. .

As a result, in the step of melting the granular raw material, it becomes possible to select the position of the double crucible composed of the quartz crucible and the bottomless cylindrical partition to a position where the heat of the heater can be sufficiently obtained. It is not necessary to increase the power of the heater, it is possible to prevent the time required for melting the granular raw material from being lengthened, and it is possible to prevent the inside of the chamber from being contaminated.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of an embodiment of a single crystal manufacturing apparatus according to the present invention.

FIG. 2 is a cross-sectional view (a) showing a configuration of a heat shield and a suspending member and a cross-sectional view (b) showing a configuration of a bottomless cylindrical partition wall in the present invention.

FIG. 3 is a cross-sectional view showing a state before melting the granular raw material of the single crystal manufacturing apparatus according to the present invention.

FIG. 4 is a cross-sectional view showing a state in which a double crucible is formed between a quartz crucible and a bottomless cylindrical partition wall after melting a granular raw material of a single crystal manufacturing apparatus according to the present invention.

FIG. 5 is a cross-sectional view showing the overall configuration of a conventional single crystal manufacturing apparatus.

[Explanation of symbols]

 1 Chamber 2 Quartz Crucible 3 Heater 4 Single Crystal Seed 4a Seed Chuck 4b Suspended Wire 5 Conventional Quartz Partition 6 Conventional Thermal Shield 8 Inner Crucible 9 Outer Crucible 10 Granular Raw Material Input Pipe 11 Crucible Shaft 12 Carbon Crucible 13 Heat Insulation Member 20 Thermal Shield 21 Suspension Member 21a Carbon Bolt 21b Molybdenum Column 22 Hooking Pin 23 Quartz Partition (Cylinder-Free Bottom Partition) 30 Granular Raw Material 31 Raw Material Melt 32 Single Crystal

Claims (4)

[Claims] 1. A granular raw material is supplied to a crucible in a chamber capable of being evacuated, a raw material melt is generated by heating the outside of the crucible with a heater, and the granular raw material is newly supplied to the crucible and the raw material melt is formed. In a single crystal manufacturing apparatus for pulling a single crystal from a single crystal, a heat shield that can be lifted and lowered and can be hung above the crucible, and that shields the single crystal being pulled from being irradiated with heat from the heater; It is suspended below the shield, and when it is lowered and placed in the crucible, it forms a double crucible together with the crucible and separates the region of the raw material melt from the region of the granular raw material for growing a single crystal. An apparatus for producing a single crystal, comprising: a bottom cylindrical partition. 2. The apparatus for producing a single crystal according to claim 1, wherein the bottomless cylindrical partition wall can be detachably hung on the heat shield. 3. The apparatus for producing a single crystal according to claim 1, wherein the heat shield is connectable to a suspending wire for pulling up the single crystal. 4. A granular raw material is supplied to a crucible in a chamber capable of being evacuated, a raw material melt is generated by heating the outside of the crucible with a heater, and the granular raw material is newly replenished to the crucible and the raw material melt is formed. In the method for producing a single crystal from which a single crystal is pulled, a heat shield that shields the single crystal being pulled from being irradiated with heat from the heater is hung above the crucible, and at the bottom of the heat shield, The bottomless cylindrical partition wall that separates the region of the raw material melt and the region of the granular raw material that forms a double crucible together with the crucible when it is lowered and placed in the crucible to grow a single crystal, is suspended. The heat shield and the bottomless cylindrical partition wall are pulled up above the crucible, the granular raw material is supplied into the crucible, and the outside of the crucible is heated by the heater to melt the granular raw material, Bottom cylinder Characterized by pulling down the heat shield and the bottomless cylindrical partition until the bottom of the partition reaches the bottom of the crucible, forming a double crucible with the crucible, and pulling a single crystal from the region of the raw material melt. And a method for producing a single crystal.