JPH04108684A - Pulling-up device for single crystal - Google Patents

Abstract

PURPOSE:To uniformly hold the composition of melt and to grow good-quality single crystal by providing a blade which agitates this melt in a crucible in the vertical direction in a pulling-up device of single crystal wherein single crystal is grown by a Czochralski process. CONSTITUTION:A crucible 1 is freely rotatably supported and also four pieces of blades 6 tilted in one direction are fitted to the internal periphery of the crucible 1 in the intervals of an equal angle. Thereby, since upward or downward flow is caused in melt 2 in accordance with the oblique direction of the blades 6 when the crucible 1 is rotated, this melt 2 is agitated in the vertical direction. Then in this state seed crystal 4 fixed to the tip of a pulling-up axis 3 is immersed in the melt 2 and single crystal 5 is pulled up and grown. Thereby, even when the melt 2 is a compound constituted of a plurality of elements large in the mutual difference of atomic weights, gravity segregation phenomena are not caused wherein heavy elements are concentrated in the bottom part of the crucible 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves immersing a seed crystal fixed at the tip of a pulling shaft into a melt in a crucible, and by pulling up the pulling shaft, a single crystal is attached to the seed crystal. The present invention relates to an apparatus for pulling a single crystal for growth, and particularly to an apparatus for stirring the melt in the crucible.

[Conventional technology and its issues]

Single crystal pulling equipment using the Czochralski method, etc.
It is necessary to maintain a uniform composition of the melt in the crucible.

A device for stirring the melt in the crucible in a conventional single crystal pulling device includes a device that includes a protrusion on the inner surface of the bottom of the crucible and stirs the melt in the crucible by rotating the crucible (Japanese Unexamined Patent Publication No. 58-208193). A device using a stirrer coaxial with the pulling shaft (Japanese Patent Application Laid-Open No. 59-203797).

JP-A-60-108396, etc.).

Although these conventional devices can stir the melt in the circumferential direction by promoting the flow in the circumferential direction of the crucible, there is a problem in that the ability to promote the flow in the vertical direction and stir the melt in the vertical direction is extremely poor. .

However, if the melt in the crucible is a compound composed of multiple elements with particularly large differences in atomic weight, a phenomenon of gravitational segregation occurs in which heavier elements concentrate at the bottom of the crucible, making it difficult to grow a good single crystal. I can't.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a stirring device that can actively change the flow of melt generated by the rotation of a crucible into a vertical flow to avoid the above-mentioned gravitational segregation phenomenon and grow a good single crystal. shall be.

[Means to solve the problem]

The device of the present invention has been made to solve the above-mentioned problems and achieve the above-mentioned objects.A seed crystal 4 fixed to the tip of a pulling shaft 3 is immersed in the melt 2 in a crucible 1, and the pulling shaft 3 is This single crystal pulling apparatus grows a single crystal 5 on a seed crystal 4 by pulling it up, and is characterized by stirring the melt 2 in the crucible 1 in the vertical direction.

In order to solve the same problem and achieve the same purpose, the first apparatus of the present invention is designed to solve the same problem and achieve the same purpose, as shown in FIGS. 1 and 2.
In a single crystal pulling device, a seed crystal 4 fixed to the tip of a pulling shaft 3 is immersed and a single crystal 5 is grown on the seed crystal 4 by pulling up the pulling shaft 3. The crucible 1 has a structure in which a plurality of blades 6 inclined in one direction are attached to the inner periphery of the crucible 1.

In order to solve the same problem and achieve the same purpose, the second device of the present invention is designed to solve the same problem and achieve the same purpose, as shown in FIGS. 1 and 4.
In a single crystal pulling device, a seed crystal 4 fixed to the tip of a pulling shaft 3 is immersed and a single crystal 5 is grown on the seed crystal 4 by pulling up the pulling shaft 3. The structure is such that a fixed cylinder 7 having spiral pleats 8 on its outer periphery is immersed in the melt 2 in the crucible 1.

A third device of the present invention solves the same problem and achieves the same objective, as shown in FIGS. 1 and 5I! A seed crystal 4 fixed to the tip of a pulling shaft 3 is immersed in the melt 2 in the crucible 1 as shown in FIG.
In a single crystal pulling device that grows a single crystal 5 on a seed crystal 4 by pulling up a pulling shaft 3, a crucible 1 is rotatably supported, and a unidirectional movement is made by cutting into the outer periphery of the melt 2 in the crucible 1. It has a structure in which a fixed cylinder 7 provided with a plurality of blades 9 and windows 10 is immersed.

[For production]

When the crucible 1 is rotated in the first apparatus of the present invention, a plurality of blades 6 attached to the inner periphery of the crucible 1 and tilted in one direction cause the crucible 1 to rotate upwardly or A downward flow occurs, and even if the melt 2 in the crucible 1 is a compound composed of multiple elements with large differences in atomic weight, this upward or downward flow will sufficiently stir it in the vertical direction. .

When the crucible 1 is rotated in the second device of the present invention, the spiral folds 8 provided on the outer periphery of the fixed cylinder 7 perform the same action as in the first device, depending on the direction of rotation and the spiral direction of the crucible 1. It turns out.

When the crucible 1 is rotated in the third device of the present invention, the melt 2 in the crucible 1 is caused to flow along the unidirectional blades 9 by the unidirectional blades 9 and windows 10 formed by a plurality of notches on the outer periphery of the fixed cylinder 7. It enters the fixed cylinder 7 through the window 10, and as a result, an upward or downward flow occurs within the fixed cylinder 7,
It has exactly the same effect as the first device described above.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the outline of the configuration of a single crystal pulling apparatus to which the apparatus of the present invention is applied. This constitutes a single crystal pulling device that grows a single crystal 5 on a seed crystal 4 by pulling the seed crystal 4. 11 is a heater that heats the crucible 1;

FIGS. 2(a) and 2(b) are a schematic plan view and a schematic vertical cross-sectional view, respectively, showing the structure of the first embodiment of the present invention apparatus in the single crystal pulling apparatus shown in FIG.

In this first embodiment, a crucible 1 is rotatably supported in the single crystal pulling apparatus shown in FIG.
It consists of four blades 6 tilted in one direction and attached at equal angular intervals.

When the crucible 1 is rotated in such a first embodiment,
4 attached to the inner periphery of this crucible I and tilted in one direction.
The blades 6 generate an upward or downward flow depending on the direction of rotation and the direction of inclination of the blades 6. For example, when the crucible 1 is rotated in the left-handed screw direction shown by the arrows in FIGS. 2(a) and 2(b), the blades 6 When the direction of inclination of the blade 6 is upward to the right as seen from the inside of the crucible as shown in Fig. 2, an upward flow occurs, and when the direction of inclination of the blade 6 is upward to the left as seen from the inside of the crucible, a downward flow occurs. Even if the melt 2 in the crucible 1 is a compound composed of a plurality of elements with large differences in atomic weight, this upward or downward flow will sufficiently agitate it in the vertical direction.

3(a) and 3) are examples in which a fixed cylinder 7 is provided in the melt 2 in the crucible 1 in the first embodiment shown in FIG. ), (b)
When the blade 6 rotates in the counterclockwise direction shown by the arrow and the inclination direction of the blade 6 is upward to the right when viewed from the inside of the crucible, a downward flow occurs inside the cylinder 7, an upward flow occurs outside the cylinder 7, and this The flow causes the melt 2 in the crucible 1 to be more significantly agitated in the vertical direction.

Note that the cylinder 7 is fixed at the upper part of the crucible 1 by known means.

FIGS. 4(a) and 4(b) are a schematic longitudinal sectional view and a schematic front view of a fixed cylinder, respectively, showing the configuration of the second embodiment.

In this second embodiment, a crucible 1 is rotatably supported, and a fixed cylinder 7 having spiral pleats 8 on its outer periphery is immersed in the melt 2 inside the crucible 1.

When the crucible 1 is rotated in such a second embodiment,
A spiral fold 8 provided on the outer periphery of the fixed cylinder 7 allows the cylinder 7 and the crucible 1 to be moved according to the rotational direction and spiral direction of the crucible 1.
An upward or downward flow is generated between the cylinder 7 and a downward or upward flow is generated inside the cylinder 7. For example, when the crucible 1 is rotated in the direction of the left-hand thread indicated by the arrow in FIG. 4(a), the spiral of the pleats 8 When the direction is set to the right-hand screw direction as shown in FIG. 4, an upward flow occurs between the cylinder 7 and the crucible 1, and a downward flow occurs inside the cylinder 7. It will have a similar effect.

FIGS. 5(a) and 5(b) are a schematic plan view and a schematic longitudinal cross-sectional view, respectively, showing the configuration of the third embodiment.

This third embodiment rotatably supports the crucible, and the lower outer periphery (see FIG. 5) is cut in one direction into the melt 2 in the crucible 1, for example, as shown in FIG. (a) A fixed cylinder 7 with eight right-handed screw blades 9 and eight windows 10 as shown.
When the crucible 1 is rotated in the left-hand screw direction shown by the arrows in FIGS. 5(a) and 5(b), the inside of the crucible is As shown in FIG. 5(a), the melt 2 flows into the cylinder 7 from outside the fixed cylinder 7 along each blade 9 through each window 10, and as a result, an upward flow occurs inside the cylinder 7. This results in the same effect as in the first embodiment.

FIG. 6 shows the top of the fixed cylinder 7 in the third embodiment of FIG.
The eight blades 9 on the outer periphery of the lower part are arranged in different directions in the upper and lower two stages, for example, the lower stage has eight blades 9 with a right-hand thread direction, and the upper stage has eight blades 9 with a left-hand thread direction. In this example, when the crucible 1 is rotated in the left-handed screw direction indicated by the arrow in FIG. It flows into the cylinder 7 through the multi-windows 10 along the same line, and conversely flows out of the cylinder 7 at the upper part (upper stage).As a result, an upward flow occurs inside the fixed cylinder 7, similar to the first embodiment above. This will have the effect of

Further, it is obvious that there is no need to explain that the fixed cylinder 7 in the stirring apparatus shown in FIGS. 5 and 6 may be provided with a bottom.

〔Effect of the invention〕

As described above, according to the present invention, the flow of the melt 2 caused by the rotation of the crucible 1 can be actively changed into a vertical flow, so that the melt 2 in the crucible 1 has a particularly large difference in atomic weight. Even in the case of a compound composed of a plurality of elements, a gravitational segregation phenomenon in which heavy elements are concentrated at the bottom of the crucible 1 does not occur, and a good single crystal can be grown.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the outline of the configuration of a single crystal pulling apparatus to which the apparatus of the present invention is applied, and FIGS. A schematic plan view and a schematic vertical sectional view showing the configuration of the embodiment, and FIGS. 3(a) and 3) respectively show an example in which the fixed cylinder is immersed in the melt in the crucible in the first embodiment of FIG. 2. A schematic plan view and a schematic vertical cross-sectional view, and FIGS. 4(a) and (b) are a schematic vertical cross-sectional view and a schematic front view of a fixed cylinder showing the configuration of the second embodiment, respectively, and FIGS. 5(a) and (b). ) are a schematic plan view and a schematic vertical cross-sectional view showing the configuration of the third embodiment, respectively, and FIG. It is a schematic vertical cross-sectional view showing an example in which the lower two stages are different. ■... Crucible, 2... Melt, 3...
... Pulling axis, 4 ... Seed crystal, 5 ...
・Single crystal, 6...Blade, 7...Fixed cylinder, 8...Spiral folds, 9...Blade, 10... ·window.

Claims (8)

[Claims] (1) A pulling shaft (3) is attached to the melt (2) in the crucible (1).
Immerse the seed crystal (4) fixed on the tip of the pulling shaft (3).
A single crystal pulling device for growing a single crystal (5) on a seed crystal (4) by pulling the crucible (1) is characterized by being equipped with a device for vertically stirring the melt (2) in the crucible (1). Single crystal pulling equipment. (2) A pulling shaft (3) is attached to the melt (2) in the crucible (1).
Immerse the seed crystal (4) fixed on the tip of the pulling shaft (3).
In a single crystal pulling device for growing a single crystal (5) on a seed crystal (4) by pulling up a crucible (1), a crucible (1) is supported rotatably, and a crucible (1) is provided with an inner periphery tilted in one direction. 2. The single crystal pulling apparatus according to claim 1, wherein a plurality of blades (6) are attached to the single crystal pulling apparatus. (3) Inner cylinder (7) fixed in melt (2) in crucible (1)
3. The single crystal pulling apparatus according to claim 2, which is obtained by immersing the single crystal. (4) A pulling shaft (3) is attached to the melt (2) in the crucible (1).
Immerse the seed crystal (4) fixed on the tip of the pulling shaft (3).
In a single crystal pulling device that grows a single crystal (5) on a seed crystal (4) by pulling up a crucible (1), a crucible (1) is rotatably supported, and a melt (2) in the crucible (1) is 2. The single crystal pulling device according to claim 1, comprising a fixed cylinder (7) provided with spiral pleats (8) on its outer periphery. (5) A pulling shaft (3) is attached to the melt (2) in the crucible (1).
Immerse the seed crystal (4) fixed on the tip of the pulling shaft (3).
In a single crystal pulling device that grows a single crystal (5) on a seed crystal (4) by pulling up a crucible (1), a crucible (1) is rotatably supported, and a melt (2) in the crucible (1) is Claim 1: A fixed cylinder (7) having a plurality of unidirectional blades (9) and windows (10) formed by notches on its outer periphery is immersed.
The single crystal pulling device described in Section 1. (6) The single crystal pulling apparatus according to claim 5, wherein a plurality of blades (9) and windows (10) are provided in a plurality of stages on the outer periphery of the fixed cylinder (7). (7) The single crystal pulling apparatus according to claim 6, wherein the plurality of blades (9) are arranged in different directions in each stage. (8) Claim 6, wherein the fixed cylinder (7) is provided with a bottom;
The single crystal pulling device according to any one of Item 7.