JPH078793A - Method for controlling conduction of thermal energy - Google Patents

Abstract

PURPOSE:To provide a method for controlling conduction of thermal energy wherein the method is adopted in a wide temperature region to set the desired temperature gradient in melt by controlling thermal energy radiated from melt. CONSTITUTION:In a device of a figure wherein a vertical Bridgman furnace is used, a vertical type boat 8 made of quartz is surrounded by heat insulating material 3 and charged with melt 11. The temperature of the vertical type boat 8 is raised by a carbon heater 9. A vessel 14 made of carbon is fitted to the bottom of the vertical type boat 8 and houses liquid gallium 15. A rotary magnet constituted of rare earth magnets 17 fitted to ringlike soft iron 16 is so rotated along a water cooling jacket 12 formed in the circumference of a flange 13 that the temperature difference of temperature sensors 6, 7 set in a silica tube 10 provided in the axial center of the boat 8 is specified. The velocity of the rotary magnet is controlled and thermal energy radiated from melt 11 is controlled through liquid gallium 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling thermal energy conduction which can be used to control the solidification rate and evaporation rate of a melt.

[0002]

2. Description of the Related Art In a method of growing a single crystal from a liquid phase which is widely used industrially, for example, a temperature at which a crystal is grown by moving or lowering a crucible containing a melt in an electric furnace having a temperature gradient. Gradient method (Bridgman method) or pulling method (Czochralski method) to pull crystal from melt surface
In such cases, it is important to control the cooling rate of the melt.

Generally, for cooling a melt in a crystallization apparatus or a crystal growing apparatus for controlling the solidification rate or evaporation rate of the melt, a method of cooling the portion to be radiated with heat, cooling with a liquid, or cooling with a liquid alkali is adopted. Has been.

Depending on the object to be cooled, water, silicone oil or the like is usually used as a cooling method at 250 ° C. or lower, and if it is higher than that, it is often cooled by alkali metal or air.

[0005]

However, among the above-mentioned cooling methods, air cooling has a slow cooling rate and cannot provide a large amount of heat radiation in a portion to be radiated. Therefore, in order to increase the amount of heat radiation, it is necessary to compare with other methods. Requires a large space.

On the other hand, although the liquid cooling method can increase the amount of heat radiation from the portion to be radiated, the control range of the heat radiation energy is narrow and therefore the cooling temperature range is limited.

Further, even in the case of liquid alkali cooling, there are problems such that the cooling temperature range is as narrow as 100 to 700 ° C. and the equipment cost is generally high.

Therefore, an object of the present invention is to provide a control method of heat energy conduction which can be adopted in a wide temperature range for controlling the heat energy radiated from the melt and setting a desired temperature gradient in the melt. To provide.

[0009]

As a result of research to achieve the above object, the present inventor has conducted thermal energy from the first heat-good conductor of the former among the two heat-good conductors of high and low types to the second heat-good conductor of the latter. When moving and dissipating, the space (vacuum or gas phase) that thermally connects the first and second good thermal conductors and liquid metal, for example, high-purity liquid gallium having a melting point of 29.8 ° C. By providing a connection part composed of and rotating the connection part or changing the distance between the two good heat conductors, the effective heat conduction area of the liquid metal can be changed.
It is possible to control the heat energy dissipated from the first good thermal conductor,
The present invention has been achieved by finding that it is an effective means for solving the problems of the prior art.

That is, the present invention is, firstly, in a method of controlling thermal energy conduction for setting a temperature gradient in the first thermal conductor by conducting thermal energy from the first thermal conductor to the second thermal conductor. , A liquid metal that thermally connects the two good thermal conductors by providing a connecting part made of a liquid metal and a space formed of a vacuum or a vapor phase between the first good thermal conductor and the second good thermal conductor A method of controlling thermal energy conduction, characterized in that the temperature gradient in the first good thermal conductor is controlled by changing the heat conducting area by the amount of heat released from the first good thermal conductor: second, the liquid metal Changing the effective heat transfer area of the liquid metal by rotating the liquid metal: Third, changing the effective heat transfer area of the liquid metal thermally connects with the liquid metal. Change in spacing between good thermal conductors Out those providing the first control method carried out by.

[0011]

In the method of the present invention, the conduction of thermal energy is controlled by changing the effective heat conduction area by the liquid metal in the connection portion provided between the two good thermal conductors.

As a method of controlling the effective heat conduction area, as shown in the schematic cross-sectional view of FIG. 2A, the first heat good conductor 1 and the second heat good conductor 2 surrounded by a heat insulating material 3 are formed. In the meantime, when stationary, a connecting portion composed of the space portion 4 and the liquid metal 5 as shown in the figure is provided, and the connecting portion is rotated as shown in the schematic cross-sectional view of FIG. , The area of the first heat-good conductor in contact with the liquid metal 5 rising along the side wall, that is, the effective heat conduction area is changed.

Further, as shown in the schematic cross-sectional view of FIG. 3, a connection portion (a space portion 4 and a liquid metal 5 as shown in the drawing is provided between the two thermal conductors 1 and 2 which are also surrounded by the heat insulating material 3. It is also possible to change the effective heat conduction area of the liquid metal which is in contact with the first good thermal conductor by providing a) and moving either of the good thermal conductors up and down to change the distance between the two.
By changing the effective heat conduction area as described above, the first temperature sensor 6 pushed into the first good thermal conductor.
The dissipated heat energy can be controlled so that the temperature difference between the second temperature sensor 7 and the second temperature sensor 7 becomes a desired value.

In order to rotate the liquid metal in the connecting portion, for example, a rotating magnet having a rare earth magnet mounted inside a ring-shaped soft iron plate is rotated around the connecting portion and flows in proportion to the rotational speed. The induced current controls the behavior of the rotating liquid metal.

The liquid metal has a melting point of 29.8.
High-purity gallium or its compound at ℃ is desirable in view of its chemical stability and wide control range.

[0016]

[Embodiment 1] FIG. 1 is a schematic sectional view of an apparatus using a vertical Bridgman furnace used in this embodiment, which will be described below with reference to this drawing.

A special type in which liquid gallium 15 is housed in the bottom of a vertical quartz boat 8 surrounded by a heat insulating material 3 and charged with a melt 11 having a melting point of 500 ° C. or higher which is heated by a carbon heater 9. A container 14 made of a carbon material is attached as shown in the figure, and the quartz tube 1 is provided at the axis of the boat 8.
In order to keep the temperature difference between the first temperature sensor 6 and the second temperature sensor 7 at zero, the rotary magnet made of a rare earth magnet attached to the ring-shaped soft iron 16 is attached to the flange 13
It was rotated along a water cooling jacket 12 provided around the.

When the rotating magnet is rotated, an induced current flows in proportion to the rotation speed, so that the liquid metal can be rotated. In the figure, the state in which the liquid gallium rises to the side surface of the container is shown.

First, 250 g of high-purity gallium, which corresponds to 90% of the volume of the container, was placed in each of the three-tiered carbon containers in the above apparatus and the temperature was raised in an argon atmosphere.
The first temperature sensor is 1000 ℃, the second temperature sensor is 9
Emission energy per unit area at 50 ° C is 4.2 W / cm
^{Was 2} .

Next, when the temperature difference between the two sensors was set to 100 ° C. and the magnet was rotated, the first and second sensors were about 950 ° C. and about 850 ° C., and the emission energy was 8.5 W. / Cm ² .

Next, when the temperature difference between both sensors was set to 200 ° C. and the magnet was rotated, about 800 ° C. was similarly obtained.
And about 600 ° C, the emission energy is 17 W / cm ²
The emission energy could be controlled as described above.

[0022]

Example 2 In Example 1, the case where the first temperature sensor in the melt 11 was 1000 ° C. or lower was described, but in this Example, the case where the temperature was higher than 1000 ° C. was tested.

Using the device of FIG. 1, the first temperature sensor is
The test was conducted at 400 ° C. and the temperature of the second temperature sensor at 1330 ° C., but the heat release energy could be controlled without any trouble as in Example 1.

[0024]

As described above, according to the method of the present invention, in order to control the solidification rate of a good heat conductor, for example, a melt, two heat good conductors are connected to each other by a liquid metal, and the liquid metal is effectively used. Since the heat conduction area is controlled, heat energy conduction, that is, heat emission energy can be controlled in a wide temperature range.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an apparatus using a vertical Bridgman furnace used in one embodiment of the present invention.

2A and 2B are schematic diagrams for explaining the operation of a liquid metal rotating type according to the present invention, in which FIG. 2A shows a state in which the liquid metal is stationary, and FIG. It is a figure which shows a mode that a metal rotates and an effective heat conduction area changes.

FIG. 3 is a schematic diagram showing how the effective heat conduction area of the liquid metal interposed between the two good thermal conductors moves up and down in the present invention.

[Explanation of symbols]

 1 1st good thermal conductor 2 2nd good thermal conductor 3 Thermal insulation 4 Space part 5 Liquid metal 6 1st temperature sensor 7 2nd temperature sensor 8 Quartz vertical boat 9 Carbon heater 10 Quartz tube 11 Melt 12 Water cooling jacket 13 Flange 14 Carbon container 15 Gallium 16 Soft iron 17 Rare earth magnet

Claims (3)

[Claims] 1. A method of controlling thermal energy conduction, wherein the temperature gradient in the first good thermal conductor is set by conducting thermal energy from the first good thermal conductor to the second good thermal conductor, wherein the first good thermal conductor is provided. By providing a connecting portion made of a liquid metal and a space portion in a vacuum or a vapor phase between the second heat conductor and the second heat conductor, and changing the effective heat conduction area of the liquid metal that thermally connects the two heat conductors, A method for controlling thermal energy conduction, characterized in that a temperature gradient in the first good thermal conductor is controlled by adjusting the amount of heat released from the first good conductor. 2. The control method according to claim 1, wherein the effective heat conduction area of the liquid metal is changed by adjusting the liquid level raising force by the high speed rotation of the liquid metal. 3. The control method according to claim 1, wherein the effective heat conduction area of the liquid metal is changed by changing an interval between thermal conductors that are thermally connected to the liquid metal.