JPH10185455A - Heat treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an arbitrary temperature distribution by controlling input heat amount (heating) and releasing heat amount, and accurately providing the distribution having an abrupt temperature gradient region in a furnace. SOLUTION: A gap corresponding to an abrupt temperature gradient region A is provided between specific heaters 3b and 3c, and a partial region 2a corresponding to the region A of a heat insulation cylinder 2 surrounding the entirety is formed of a material having larger thermal conductivity than that of the other region. Thus, heat amount released out of the apparatus between the heaters 3b and 3c is increased. During this period, more abrupt temperature gradient region can be stably formed. As a result, seeding can be more effectively conducted to stably manufacture a single crystal of high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus such as a single crystal manufacturing apparatus for growing a single crystal from a raw material melt by controlling a temperature distribution in a furnace.

[0002]

2. Description of the Related Art As a single crystal production method of a III-V compound semiconductor such as GaAs or a II-VI compound semiconductor such as CdTe, a solidification method with a vertical temperature gradient (VGF method) and a vertical Bridgman method (VB method)
Method), solidification method with horizontal temperature gradient (HGF method), horizontal Bridgman method (HB method), pulling method (CZ method), etc. are used.

In these methods, since it is necessary to strictly control the temperature distribution in the growth furnace, a multi-stage heater structure in which a plurality of heaters are arranged adjacent to each other is generally adopted.
Further, various methods have been conventionally proposed in order to obtain, for example, a high-quality single crystal having a low dislocation density and excellent crystallinity. For example, in Japanese Patent Application Laid-Open No. 5-70276, a plurality of heaters are arranged in a plurality of stages inside a heat insulating cylinder along the inner wall of the furnace.
In the VGF method single crystal manufacturing equipment, heat shields between heaters are used to minimize mutual interference due to heat radiation and thermal convection between heaters, improve the controllability of individual heaters and improve temperature accuracy. A board interposed device is disclosed.

However, if a heat shield plate is interposed only between heaters as in the apparatus described in the above-mentioned publication, there is a limit to the temperature distribution in the furnace obtained. That is, the temperature distribution obtained in the furnace is determined by the balance between the amount of heat input obtained by heating by the heater and the amount of heat escaping from the apparatus (furnace). Therefore, for example, Japanese Patent Application Laid-Open No. HEI 5-39878 discloses an apparatus in which the amount of heat escaping from the lower part of the apparatus (the lower part of the vessel) is controlled in the same vertical single crystal manufacturing apparatus as described above. That is, a refrigerant pipe penetrating the bottom wall of the furnace body is inserted into a crucible support that supports the crucible from below, and the amount of heat escaping from the apparatus is controlled by the cooling body.

[0005]

However, in the configuration described in Japanese Patent Application Laid-Open No. Hei 5-139778, the temperature inside the furnace can be controlled to some extent, but the cooling unit is installed at the lower part of the furnace body (or Because the temperature distribution is limited to the upper part, it is difficult to control the temperature distribution in a certain limited range, for example, to steepen the temperature gradient at the solid-liquid interface.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to control the amount of heat input (heat generation) and the amount of heat escaping, and to control the temperature distribution having a steep temperature gradient region in the furnace. An object of the present invention is to provide a heat treatment apparatus that can obtain an arbitrary temperature distribution with high accuracy.

[0007]

Means for Solving the Problems In order to achieve the above object, a heat treatment apparatus according to the present invention comprises a plurality of heaters arranged in multiple stages inside a heat insulating cylinder provided along the inner wall of a furnace.
In a heat treatment apparatus that forms a temperature distribution having a steep temperature gradient region having a large temperature gradient locally in an internal space surrounded by these heaters along the arrangement direction of the heaters, a gap corresponding to the steep temperature gradient region has a gap corresponding to the steep temperature gradient region. In addition to being provided between the specific heaters sandwiching the temperature gradient region, the heat insulating cylinder is characterized in that a part of the region corresponding to the steep temperature gradient region is formed of a material having higher thermal conductivity than other regions.

That is, when a plurality of heaters are arranged in multiple stages and a predetermined temperature distribution is formed in an internal space surrounded by the heaters, the heat generated by the heaters usually escapes directly to a furnace body outside the heaters. In order to minimize the amount of heat escaping to the furnace through each heater and minimize the temperature drop between the heaters, a small heat conductivity An insulation tube made of a material is provided.

On the other hand, in the present invention, a gap corresponding to the steep temperature gradient region is provided between the specific heaters to form a heat flow direction between the specific heaters, and one of the heat insulating cylinders located in the heat flow direction is provided. By forming the region from a material having a high thermal conductivity, the amount of heat flowing in that direction is increased. As a result, when one of the specific heaters is controlled at the set temperature on the high temperature side of the steep temperature gradient region, the amount of heat input thereby flows out of the steep temperature gradient region in the above-described heat flow direction. Occurs.
Then, by determining and controlling the low-side control temperature of the other heater so that this temperature drop becomes a predetermined steep temperature gradient, it is possible to stably form a steep temperature gradient region between these heaters. It becomes possible.

On the other hand, when a configuration is adopted in which a heat insulating member is interposed between the heaters to reduce mutual interference between the heaters, the heat insulating member between the specific heaters sandwiching the steep temperature gradient region is additionally provided. It is preferable that the heat insulating member is formed of a material having a lower thermal conductivity than that of the heat insulating member. By the heat insulating member between the specific heaters, the flow of heat between the specific heaters sandwiching the specific heaters is suppressed, and the temperature gradient in this portion can be made steeper.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] Next, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 1A shows a heat treatment apparatus configured as a single crystal manufacturing apparatus by a solidification method with a vertical temperature gradient (VGF method). This apparatus includes a pressure vessel 1 as a furnace body having a pressure-resistant structure. The pressure vessel 1 includes a cylindrical vessel main body 1a, an upper lid 1b for closing an upper opening thereof, and a lower lid 1c detachably and hermetically attached to a lower opening.

Inside the pressure vessel 1, there is arranged a heat insulating cylinder 2 composed of an upper closed cylindrical body along the lower surface of the upper lid 1b and the inner surface of the container body 1a. A plurality of upper and lower stages (five stages in the figure) of cylindrical heaters 3a to 3e are provided in the heat insulating cylinder 2, and an inverted cup shape is formed so as to surround the inner space of the heaters 3a to 3e. The internal chamber 4 is disposed so as to be placed on the lower lid 1c. The inner chamber 4 is made of a material having heat resistance and gas impermeability, for example, a high melting point metal or ceramic such as molybdenum, or a special carbon material such as carbon coated with pyrolytic graphite or glassy carbon. .

A cylindrical support 5 is provided on the lower lid 1c in the internal chamber 4, and on the crucible 6 held by the support 5 at a position substantially at the center of the high-pressure vessel 1, A crucible 7 as a raw material storage container is supported. The crucible 7 is made of, for example, p-BN, and at the lower end thereof, a thin tube portion 7a into which a rod-shaped seed crystal 15 described later is inserted is provided, and a large-diameter cylinder portion 7b is provided above the tapered portion 7c.
It is provided continuously through. The tapered portion 7c and the thin tube portion 7a are fitted into support holes that are recessed downward from the upper surface of the crucible base 6, and the crucible 7 is supported almost upright at the center of the upper side in the internal chamber 4. I have.

On the other hand, a thick tube-shaped reservoir 8 provided with a center hole through which the support base 5 penetrates is provided on the lower side in the internal chamber 4, and this reservoir 8 is recessed downward from the upper surface thereof. The high dissociation pressure element 9 can be accommodated in the annular groove. Although not shown, the upper lid 1b is provided with a gas supply / discharge passage for injecting and discharging an inert gas such as an argon gas into the pressure vessel 1 under pressure. The chamber 4 has a communication passage formed at the lower end near the lower lid 1c to communicate the inside and outside of the internal chamber 4 with each other.

Between the heat insulating cylinder 2 and the inner chamber 4, six zone partitioning heat insulating materials 11a to 11f and five five heat insulating materials 11a to 11f are arranged from above so as to individually surround the heaters 3a to 3e from above and below and from outside. The outer heat insulating materials 12a to 12e are alternately arranged. Each of the zone partitioning heat insulating materials 11a to 11f has an outer peripheral surface close to the inner surface of the heat insulating cylinder 2, while an inner peripheral surface of each of the heaters 3a to 3e.
It is formed in a ring shape protruding more inward in the radial direction than the outer surface of the inner chamber 4 as much as possible. Further, each of the outer heat insulating materials 12a to 12e which are interposed between the outer peripheral edges of the zone partitioning heat insulating materials 11a to 11f is formed in a cylindrical shape whose inner peripheral surface is as close as possible to each of the heaters 3a to 3e. I have.

When the heaters 3a to 3e are energized, the temperature distribution as shown in FIG.
It is controlled to be formed within. That is, the crucible 7
The upper end side of the seed crystal 15 inserted into the narrow tube portion 7a is the melting point temperature mp of the raw material (for example, 1238 ° C. when the raw material is GaAs), and the upper and lower sides of the melting point temperature range are respectively predetermined temperature than the temperature mp higher temperature side set temperature T _H
A high-temperature region A _H held substantially constant in a low temperature range A _L held substantially constant at a predetermined temperature that is lower cold side temperature setting T _L than the melting point temperature mp is formed. In addition, low temperature range A _L
Below the can, in order to heat the high dissociation pressure element 9 to be accommodated in the reservoir 8, a reservoir heating zone A, which is held approximately constant at lower reservoir heating set temperature T _R than the low temperature side set temperature _R is formed.

As a result, the first steep temperature gradient region A _G1 is formed between the high temperature region A _H and the low temperature region A _L, and the low temperature region A _{L is formed.}
A second steep temperature gradient area A _G2 is formed between the first heating element and the reservoir heating area A _R. The gaps respectively corresponding to the first and second steep temperature gradient areas A _G1 and A _G2 are formed from the second, third and fourth heaters 3b.
Provided between 3c and 3d, further interposed in each of these gaps, the third and fourth stages of zone insulation from the top
Partial regions (hereinafter, referred to as specific height regions) 2a and 2b of the heat insulating cylinder 2 surrounding the outside of 11c and 11d are formed using a material having higher thermal conductivity than other regions.

Next, an operation procedure for growing a GaAs single crystal using the above-described apparatus will be described. First, a seed crystal 15 made of a rod-shaped GaAs single crystal is placed in the thin tube portion 7a of the crucible 7.
And about 6 kg of GaAs polycrystal was filled thereon as a raw material for growing a single crystal. On the other hand, the reservoir 8 was filled with an appropriate amount of As as the high dissociation pressure element 9. Then, the crucible 7 and the reservoir 8 and the inner chamber 4 are connected as shown in FIG.
Is installed in the pressure vessel 1 as shown in FIG.
Next, through the gas supply / discharge path, the inside of the pressure vessel 1 is evacuated and replaced with argon gas twice, and then the argon gas is supplied until the inside of the high pressure vessel 1 is pressurized to about 2 kgf / cm ^2. Filled.

Thereafter, energization of each of the heaters 3a to 3e is started, the temperature inside the internal chamber 4 is raised while maintaining a temperature distribution state in which the temperature is higher as it goes upward.
Each of the heaters 3a to 3a is formed so that the temperature distribution shown in FIG.
The power supply to e was controlled. The above temperature distribution indicates that the temperature at the height position on the upper end side of the thin tube portion 6a of the crucible 6 is GaAs.
With the melting point mp (= 1238 ° C.), the upper heater 3a is set so that the temperature gradient in the first steep temperature gradient region A _G1 is approximately 20 ° C./cm with the melting point temperature range mp substantially at the center.・ 3b,
The power supplied to the lower heater 3c was controlled.

As a result, the raw materials in the crucible 7 are all melted to form a raw material melt 16, and the upper end side of the seed crystal 15 is partially melted, so that the raw material melt 16 is seeded. The heaters 3d and 3e at the height positions corresponding to the reservoir 8 are
Temperature of the reservoir heating zone A _R was controlled supply power to approximately 618 ° C.. By heating the high dissociation pressure element 9 in the reservoir 8 at this temperature, As vapor corresponding to the equilibrium vapor pressure of As at the melting point temperature of GaAs of about 1 atm is generated from the reservoir 8, and this As vapor causes 4 is satisfied. Thereby, the subsequent single crystal growth is performed in a state where the dissociation of the compound semiconductor is suppressed.

As described above, the temperature distribution in the internal chamber 4
After forming and seeding, the low-temperature region A_LBelow
Side temperature distribution is maintained as it is, and the first steep temperature gradient area
Area A _G1Moves gradually upward from the height shown in Fig. 1 (b).
So that the power supplied to each of the heaters 3a to 3c is controlled
The raw material melt 16 in the pot 7 is solidified gradually upward from the seed crystal 15 side.
And a single crystal was grown.

After the raw material melt 16 in the crucible 7 is completely solidified and the single crystal growth is completed, the power supply to the heaters 3a to 3e is stopped, and then, when the furnace temperature reaches about 300 ° C. An operation of discharging the argon gas in the pressure vessel 1 to the outside of the furnace is performed. When the temperature of the pressure vessel 1 drops to about room temperature, the lower lid 1c is lowered to open the pressure vessel 1, and the crucible 7 is collected to take out the grown crystal. went. With this operation, a length of about 250
A high quality GaAs single crystal with few crystal defects was obtained in mm.

As described above, in the present embodiment, simply
Seeding at the beginning of crystal growth is the second and third steps from the top.
Between the stage and the heater (hereinafter referred to as specific heater) 3b / 3c
The upper end of the seed crystal 15 is located at
First steep temperature gradient area A between 3b and 3c_G1Formed and done
It is. At this time, the first steep temperature gradient area in the heat insulating cylinder 2
Area A_G1Is formed of a material with high thermal conductivity
In this area A _G1Steeper temperature gradient at
It can be. In other words, such an insulated tube is
Normally, the calorific value of the heater is directly transferred to the furnace outside the heater.
Minimize the amount of escape and at the same time to the furnace through each heater
And the amount of heat that escapes to reduce the temperature drop between heaters
Use a material with low thermal conductivity to minimize generation
Formed.

On the other hand, in the present embodiment, the region 2a corresponding to the space between the specific heaters 3b and 3c in the heat insulating cylinder 2 is provided.
Is formed of a material having a higher thermal conductivity than the other regions, the amount of heat that escapes to the furnace through the space between the specific heaters 3b and 3c is locally increased, and as a result, the specific heater 3b・ The temperature drop is large between 3c. Therefore, the upper specific heater 3b is controlled by the high-temperature side set temperature T _H of steep temperature gradient region and a particular heater 3b
By setting and controlling the low-temperature control temperature of the lower specific heater 3c so that the temperature drop occurring between 3c becomes a gradient corresponding to a predetermined steep temperature gradient, these heaters 3b and 3c
In the meantime, it is possible to stably form the steep temperature gradient region of, for example, 20 ° C./cm.

As a result, the melting point temperature range mp
The amount of displacement in the height direction is suppressed to a small value by the steep temperature gradient, so that a state in which the melting point temperature range mp is located in the middle of the seed crystal 15 can be reliably obtained. Thereby, seeding performed by melting part of the seed crystal 15 is reliably performed, and a high-quality single crystal with few defects can be obtained in the subsequent crystal growth operation.

Further, in the above embodiment, each of the heaters 3a to 3a
3e is the zone section heat insulating material 11a to 11f and the outside heat insulating material 12a to
12e, the heat radiation between the heaters and the mutual interference due to gas convection are suppressed, and the space in the divided area for each of the heaters 3a to 3e and the space between the heaters 2 Since the space is configured to be as small as possible, the influence of gas convection in the partitioned area of each of the heaters 3a to 3e and in the entire furnace is also suppressed. As a result, each heater 3a ~
Since the independence of control for each 3e is improved and temperature fluctuations are greatly suppressed, the temperature distribution during single crystal growth is stabilized, and it is possible to obtain a single crystal with even higher quality. Has become.

In the above, the dissociation of the GaAs material in the crucible 7 is suppressed by generating As vapor in the reservoir 8 and growing the single crystal while controlling the vapor pressure in the internal chamber 4. From the melt 16, it becomes possible to grow a single crystal of a compound semiconductor having an intended composition over the whole. Therefore, since it is not necessary to perform the operation of vacuum-sealing the crucible required by the above-described conventional apparatus, a single crystal of excellent quality can be manufactured by a simpler operation.

Furthermore in this case, the reservoir heating zone A _R of height corresponding to the reservoir 8, the low-temperature side set temperature T _L of the upper controlled by the reservoir heating set temperature T _R of the provided temperature difference That is, even at the height corresponding to the second steep temperature gradient area A _G2 during this time, the specific height area 2b of the heat insulating cylinder 2 is made of a material having a large thermal conductivity as described above.
The gradient in the temperature gradient region A _G2 can be made steeper. As a result, the temperature distribution as described above can be formed by shortening the height dimension of the entire apparatus, so that the apparatus can be downsized accordingly.

Further, the first and second steep temperature gradient regions A _G1
・ Zone section insulation material 11 located at each height position of A _G2
c and 11d are also other zone insulation materials 11a, 11b, 11e,
If a material having a lower thermal conductivity than 11f and the outer heat insulating materials 12a to 12e is used, in these regions A _G1 and A _G2 , the flow of heat in the vertical direction is suppressed, and each of the regions A _G1 and A _G
The temperature gradient at _G2 can be steeper.

The heat insulating cylinder 2 and the heat insulating materials 11a to 11f and 12a to 12e having different thermal conductivities are made of, for example, a felt-like material made of carbon or ceramics, a molded heat insulator, a foil-like material, or the like. Various heat insulator materials can be selectively used according to the temperature, the atmosphere, and the like. Table 1 shows typical heat insulator materials and thermal conductivity. By properly using these materials, a desired temperature distribution can be formed.

[0031]

[Table 1]

Second Embodiment Next, another embodiment of the present invention will be described with reference to FIG. Note that members having the same functions as the members described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1A shows a single crystal manufacturing apparatus configured by applying the present invention to an apparatus of the vertical Bridgman method (VB method). In this device,
A crucible moving shaft 20 that can vertically move through the lower lid 1c in an airtight manner is provided, and at the upper end of the crucible moving shaft 20, the crucible 7 is supported substantially upright as described above.

A drive mechanism (not shown) for driving the crucible moving shaft 20 up and down is connected to the leading end of the crucible moving shaft 20 to the outside. By operating the driving mechanism to move the crucible moving shaft 20 up and down, the crucible 7 moves up and down integrally with the crucible moving shaft 20 in the internal chamber 4. On the other hand, in the figure, four upper and lower cylindrical heaters 3a to 3d are arranged, and four outer insulating materials 12a to 12d and four zone partitioning insulating materials 11a to 11d are arranged to individually surround these heaters 3a to 3d. 11d are provided alternately from above, almost as in the first embodiment.

FIG. 3 shows a state in which the crucible 7 is located at an upper limit position in the vertical movement range. At this time, the narrow tube portion 7a of the crucible 7 is set at a substantially central height in the pressure vessel 1. It is located. Then, at the height corresponding to this position, the second-stage zone section heat insulating material 11b from the top
In the heat insulating cylinder 2, the specific height region 2a surrounding the outside of the zone partitioning heat insulating material 11b is formed using a material having a higher thermal conductivity than the other regions. .

When a GaAs single crystal is grown using this apparatus, for example, the seed crystal 15 and an As polycrystal as a raw material are first accommodated in the crucible 7 as in the first embodiment.
The reservoir 8 is filled with an appropriate amount of As as a high dissociation pressure element 9 and set in the high-pressure vessel 1 as shown in FIG. Thereafter, the inside of the high-pressure vessel 1 is replaced with an argon atmosphere, and then the power supply to each of the heaters 3a to 3d is started so that a temperature distribution as shown in FIG. And controls the power supplied to each of the heaters 3a to 3d.

In other words, this temperature distribution indicates that the temperature at the height position on the upper end side of the thin tube portion 6a of the crucible 6 is the melting point of GaAs.
mp (= 1238 ° C.), a steep temperature gradient area A _G having a temperature gradient of about 20 ° C./cm is formed substantially at the center of the melting point temperature range mp, and above the heater 3a. by 3b, a high temperature range a _H held substantially constant at a high temperature side set temperature T _H by a predetermined temperature than the melting point temperature mp is formed. On the other hand, the lower portion of the steep temperature gradient region A _G is provided with the high-dissociation pressure element 9 in the reservoir 8 by the heaters 3c and 3d in the bottom two stages.
A reservoir heating area A _R that is maintained substantially constant at a reservoir heating set temperature T _R for heating is formed.

By forming such a temperature distribution, the raw materials in the crucible 7 are all melted to form a raw material melt 16, and the upper end side of the seed crystal 15 is partially melted. Seeding to 16 is performed. In the present embodiment, the single crystal growing operation from this state is performed by lowering the crucible moving shaft 20 at a predetermined speed while maintaining the above temperature distribution. As a result, the raw material melt 16 in the crucible 7 sequentially moves from the lower side through the melting point temperature range mp to the lower temperature side, and is thereby solidified from the lower side in contact with the seed crystal 15 to form a single crystal. Crystals grow.

After the entire raw material melt 16 has been solidified and the single crystal growing operation has been completed, each heater 3a
The power supply to ~ 3d is stopped, and the growth crystal is taken out after the inside of the furnace has dropped to almost room temperature. in this way,
Also in the present embodiment, the specific height region 2a having a height corresponding to the steep temperature gradient region _AG in the heat insulating cylinder 2 is formed of a material having higher thermal conductivity than other regions. The temperature gradient of A _G can be made steeper, so that seeding can be reliably performed. Further, in the present embodiment, this steep temperature gradient state is maintained as it is even at the solid-liquid interface that changes as the single crystal grows from the raw material melt 16.

When the temperature gradient at the solid-liquid interface is large, even if there is a temperature fluctuation at the solid-liquid interface, the effect is smaller than when the temperature gradient is small. For example, when the temperature gradient is 2 ° C./cm and 20 ° C./cm, the fluctuation of the solid-liquid interface when the temperature gradient is 2 ° C./cm even if the temperature fluctuation is ± 0.5 ° C. ± 0.25cm Fluctuation of solid-liquid interface when temperature gradient is 20 ℃ / cm ± 0.025c
m, which indicates that the effect of temperature fluctuation can be reduced.

As described above, when the influence of the temperature fluctuation is small, it is possible to prevent re-melting and re-growth of the once solidified portion in the vicinity of the solid-liquid interface, and it is possible to obtain a high-quality single crystal having a low dislocation density. Even if the temperature fluctuations are minimized, it cannot be made zero, so even if such temperature fluctuations occur, the influence of such fluctuations will be reduced, and the generation of twins and the like will be suppressed, and a good quality with less dislocations will be obtained. A single crystal can be obtained.

It should be noted that also in the apparatus of the present embodiment, the zone partitioning heat insulating material 11 having a height corresponding to the steep temperature gradient area A _G.
b is formed using a material having a lower thermal conductivity than the other heat insulating materials 11a and 11c and 12a to 12d, so that the region A _G
Can be made steeper. Further, in the present embodiment, the lower side of the steep temperature gradient region A _G is set as the reservoir heating set temperature T _R, and therefore, the temperature difference between each set temperature above and below the steep temperature gradient region A _G is large. Accordingly, the thickness of the zone partitioning heat insulating material 11b corresponding to the area _AG is made thicker than the other zone partitioning heat insulating materials 11a and 11c. This eliminates the need to provide a low-temperature region A _L between the high-temperature region A _H and the reservoir heating region A _R , so that the overall device shape can be made smaller.

The embodiments described above do not limit the present invention, and various modifications can be made within the scope of the present invention. For example, in each of the above embodiments, an example in which the present invention is applied to a single crystal growth apparatus of the VGF method / VB method is described. However, the present invention is applied to a single crystal manufacturing apparatus of another method such as a horizontal Bridgman method (HB method). It is possible to configure by applying the invention.

Further, when sintering a green compact, heat treatment equipment other than the single crystal production equipment, for example, forms a temperature distribution in the furnace with a narrow sintering temperature range and a temperature gradient sandwiching the sintering temperature as steep as possible. The present invention can be applied to other heat treatment apparatuses such as a sintering apparatus in which an object to be processed is sequentially passed through a sintering temperature region from one end side to the other end side and sintered. It is. Further, a steep temperature gradient is provided so that the high-temperature side heating region and the low-temperature side heating region can be stably formed close to each other in one apparatus, so that the workpiece can be moved from the high-temperature portion to the low-temperature portion. The heat treatment apparatus can be configured to be moved in a short time to thereby impart a quenching effect to the object to be processed.

[0044]

As described above, according to the present invention,
To stably form a steep temperature gradient region between heaters by partially forming the heat insulating cylinder surrounding the heaters from a material having high thermal conductivity and controlling the amount of heat escaping through the space between heaters to the outside of the device. Can be. As a result, a wide temperature distribution having a steep temperature gradient can be accurately obtained in the furnace. As a result, for example, in a single crystal manufacturing apparatus, seeding can be performed more reliably, and the state of the solid-liquid interface can be more controlled. Since it can be performed precisely, it is possible to stably produce a high-quality single crystal.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and FIG.
(a) is a schematic vertical sectional view showing a heat treatment apparatus configured as a single crystal production apparatus of the VGF method, and (b) is a graph showing a temperature distribution in the apparatus during a single crystal growth operation.

FIG. 2 shows another embodiment of the present invention, and FIG. 2 (a) is a schematic longitudinal sectional view showing a heat treatment apparatus configured as a single crystal production apparatus of the VB method, and FIG. 2 (b). Is a graph showing a temperature distribution in the apparatus during a single crystal growing operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pressure vessel (furnace body) 2 Heat insulation cylinder 2a ・ 2b Specific height area 3a ～ 3e Heater 7 Crucible 11a ～ 11f Zone division heat insulation material 12a ～ 12e Outer heat insulation material 15 seed crystal 16 Raw material melt A _G1・ A _G2・ A _G steep temperature gradient region

Claims (2)

[Claims] A plurality of heaters are arranged in multiple stages inside a heat insulating cylinder provided along the inner wall of a furnace, and a temperature having a steep temperature gradient region having a locally large temperature gradient in an internal space surrounded by the heaters. In a heat treatment apparatus that forms a distribution along a direction in which heaters are arranged, a gap corresponding to the steep temperature gradient region is provided between specific heaters sandwiching the steep temperature gradient region, and the heat insulating cylinder is provided in the steep temperature gradient region. A heat treatment apparatus, wherein a corresponding partial region is formed of a material having higher thermal conductivity than other regions. 2. A heat insulating member is interposed between each heater, and the heat insulating member between the specific heaters is formed of a material having a lower thermal conductivity than other heat insulating members. The heat treatment apparatus according to claim 1.