JPH0161238B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation heating apparatus used for manufacturing single crystals by the floating zone method.

A radiation heating device places a thermal light source at one focus of a reflecting mirror made of a spheroidal mirror, places a sample at the other focus, and heats the light (radiation) emitted from the thermal light source.
The light is focused on a focal point on the sample side and heats the sample. This device has a single elliptical type where the reflecting mirror is made up of only one spheroidal surface, a bielliptic type where the reflecting mirror is made up of a combination of two spheroidal surfaces, and a bielliptic type where the reflecting mirror is made up of a combination of two spheroidal surfaces, and a three or more spheroidal reflecting mirror. There is a multi-elliptical type that is composed of a combination of surfaces.

Usually, in a radiation heating device, a core tube made of heat-resistant glass such as quartz is attached to the outside of the sample in order to prevent contamination of the reflecting mirror and to surround the sample with a desired atmospheric gas. The present invention relates to a structure for mounting this furnace core tube.

Next, the drawbacks of the conventional radiation heating device will be explained with reference to the drawings.

FIG. 1 is a partial side view showing a main part of a conventional single elliptical radiation heating device in cross section.

In the figure, 101 is a reflecting mirror, and its reflecting mirror surface 102 is an ellipsoid of revolution obtained by rotating an ellipse with F ₁ and F ₂ as focal points on an axis passing through F ₁ F ₂ . Further, the reflecting mirror 101 is a fixed reflecting mirror section 1 fixed to the device.
03 and an opening/closing reflecting mirror section 104 that can be opened and closed. 105 is one focal point F ₁ of the reflecting mirror surface 102
A halogen lamp is usually used, but a xenon lamp is often used when high heating temperatures are required.

106 is the upper sample, 107 is the lower sample,
The end faces of these samples 106 and 107 are reflective mirror surfaces 1
The light emitted from the thermal light source lamp 105 is focused on _{the focal point F 2 and} heats the samples 106 and 107 in the melting zone 108.
(melting zone).

Further, 109 is a reactor core tube, and a reflecting mirror surface 102
In addition to preventing the gas generated from the samples from reaching and adhering to the reflecting mirror surface and reducing the reflection efficiency, the reactor core tube is also sealed off from the samples 106 and 107 to prevent the reflection efficiency from decreasing. It is installed for the purpose of filling the surrounding area with atmospheric gas at a predetermined pressure, and is made of heat-resistant glass such as quartz. The core tube 109 has upper and lower core tube attachment rings 110, 111 and O-ring holders 112, 11.
Upper shaft bearing 116 and lower shaft bearing 117 by 3 and 0 rings 114 and 115, respectively.
Fixed.

On the other hand, the upper sample 106 is attached to the upper shaft 119 via the upper sample holder 118, and the lower sample 107 is attached to the upper shaft 119 via the upper sample holder 118.
is connected to the lower shaft 12 via the lower sample holder 120.
1, respectively.

The upper shaft 119 has an upper shaft bearing 116,
It is rotatably fixed by an upper shaft holder 122 and an upper slough stopper 123, and is rotated by a belt drive from a motor 124 fixed to the upper shaft holder 122. Also, the lower shaft 121
are lower shaft bearing 117, lower shaft holder 1
25 and a lower thrust stopper 126, and is rotated by a belt drive from a motor 127 fixed to the lower shaft holder 125.

Pulley 12 for rotationally driving the upper and lower shafts
8, 129 are upper and lower shaft holders 122, 12
5, and the upper and lower shafts and pulleys 128, 129 are connected to each other by means such as screws or pins so that torque can be transmitted, and the upper and lower shafts and pulleys 128, 129 are removable. It has a structure.

Further, the reflecting mirror 101 is fixed to the main frame 130, the upper and lower shaft bearings 116, 117 and the lower shaft holder 125 are fixed to the movable frame 131, and the movable frame 131 is attached to the main frame 13.
Feed screw 1 of sample feed mechanism 132 fixed at 0
33 allows it to move up and down. That is, the relative positions of the sample and the reflecting mirror can be moved by the sample feeding mechanism 132. Furthermore, the upper shaft holder 122 is moved up and down with respect to the movable frame 131 by the feed screw 134 of the shaft adjustment mechanism 133 fixed to the movable frame 131, so that the vertical relative positions of the upper shaft and the lower shaft can be adjusted.

When manufacturing a single crystal with such a conventional structure, a crystal to be used as a seed crystal is used as the lower sample 107, and a sintered material of the same material as the seed crystal for the crystal to be grown is used as the upper sample 106. Using a rod or polycrystalline material rod, adjust the sample feeding mechanism and shaft adjustment mechanism to set the opposing end surfaces of the upper and lower samples near the focal point _F2 of the reflector, then turn on the thermal light source lamp to heat the upper and lower samples. The upper and lower samples are joined by the melting region 108, and the sample feeding mechanism 1
32, the upper and lower samples are gradually moved downward to gradually move the melting zone and grow a desired single crystal.

In this case, an atmosphere gas suitable for each sample (e.g. O ₂ , N ₂ , Ar, He, etc.) is placed around the sample.
It is desirable to cover the inside of the furnace tube 109 with a certain amount of air by injecting the atmospheric gas through the atmospheric gas inlet 135 opened in the lower shaft bearing and exhausting it through the atmospheric gas outlet 136 in the upper shaft bearing. This can be achieved by filling it with a flow of atmospheric gas.

Also, some samples generate gas when heated, but the inside of the core tube is O-ring 114, 1
15, 137, 138. The generated gas will not reach the surface of the reflector, be cooled and adhere to it, and reduce the reflectance of the reflector.
Even if the furnace core tube becomes cloudy due to adhesion of generated gas, 1
If the core tube is replaced after each experiment, the reduction in heating efficiency will be small and pose no practical problem. Of course, there are cases in which the generated gas is harmful, but by passing the gas emitted from the atmospheric gas outlet through a harmful gas treatment means such as a trap, it is possible to prevent it from adversely affecting the health of the workers.

Furthermore, in order to reduce the amount of gas generated, it is possible to reduce the pressure of the atmospheric gas in the reactor core tube to several atmospheres, but in this case as well, by closing the valve (not shown) connected to the atmospheric gas inlet and outlet, the high-pressure atmosphere can be reduced. It is possible to seal gas within the reactor core tube.

Although the core tube plays a large role in this way, there have been many problems in the past in attaching and detaching it. Next, we will discuss the method of attaching and detaching the core tube in conventional equipment and the problems associated with attaching and detaching it.

FIG. 2 is a cross-sectional view of the main part of the radiation heating apparatus shown in FIG. 1, showing an operation for attaching and detaching the furnace tube in the conventional radiation heating apparatus. As you can see from the figure,
When attaching and detaching the reactor core tube, first open the opening/closing reflector 104, then open the upper shaft 11 with the upper sample 106.
9 and lower shaft 121 with lower sample 107
are removed from the device by pulling them upward and downward, respectively, and then the core tube mounting rings 110, 111 and the O-ring holders 112, 11 are removed.
The reactor core tube with the No. 3 and O rings 114 and 115 still attached is inserted or removed obliquely into the upper shaft bearing 116.

Conventional radiation heating equipment was designed to perform operations like this, so in order to pull the shaft up and down with the sample still attached, a space larger than the length including the shaft and sample was created above and below the equipment. It was necessary to secure. Therefore, the height of the apparatus needs to be more than twice the total length _S1 from the upper shaft to the lower shaft in FIG. 1, making the height of the apparatus extremely large. For example, in a conventional single elliptical radiation heating device, the length from the bottom end of the lower shaft to the top end of the lower sample is approximately 400 mm, so there is approximately 400 mm at the bottom of the device.
Since the length from the top of the upper shaft to the bottom of the upper device is approximately 550 mm, a space with a height of approximately 550 mm is required above the device, for a total of approximately 950 mm. The extra height was needed.

Furthermore, when attaching and detaching the upper and lower shafts, it is necessary to perform troublesome work such as releasing the connection between the pulley and the upper and lower shafts and removing the thrust stopper. He was forced to work in an awkward position and was extremely difficult to work with. For example, in the example shown in FIG. 1, the upper pulley 128 is located above the floor.
1650mm, and the position of the lower pulley 129 is above the floor.
It is 450mm.

Furthermore, in order to attach or remove the core tube in conventional equipment, it is necessary to attach obstacles such as core tube rings 110 and 111 to the core tube in advance, and to fix the core tube to the upper and lower shaft bearings using the screws of the core tube attachment ring. The work involved poor workability due to the screw connection.

As described above, with conventional radiation heating equipment, the height of the equipment is large, and the work of attaching and detaching the reactor core tube is extremely complicated.
There were drawbacks such as being forced to work in an awkward position. The present invention eliminates these drawbacks by:
The structure is such that the core tube can be held inside the reflector. A detailed explanation will be given below with reference to the drawings.

FIG. 3 is a cross-sectional side view of a main part of a single elliptical radiation heating device showing an embodiment of the present invention. In the figure, 201 is a reflecting mirror, and its reflecting mirror surface 202 is an ellipsoid of revolution having focal points F ₁ ' and F ₂ '. Further, the reflecting mirror 201 includes a fixed reflecting mirror section 203 and an openable/closable reflecting mirror section 204.
A thermal light source lamp 205 is placed at one focal point F ₁ ' of the reflecting mirror surface 202. 206 is the upper sample, 2
07 is the lower sample, and 208 is the melting zone.

A furnace core tube 209 is composed of a glass tube 210 made of heat-resistant glass such as quartz and a cap 211 made of a heat-resistant elastic material such as silicone rubber placed over both ends of the glass tube 210. The furnace core tube 209 is pressed and fixed within the reflector by a furnace tube holder 213 by the pressing force of a compression coil spring 212 . The core tube holder 213 can be moved up and down within the reflector by operating a lever 214.

On the other hand, the upper sample 206 is attached to the upper sample holder 21.
5 to an upper shaft 216, and the upper shaft 216 is rotatably fixed by an upper shaft bearing 217 and rotationally driven by a motor 218. Further, the lower sample 207 is fixed to the lower shaft 220 via the lower sample holder 219.
0 is rotatably fixed by a lower shaft bearing 221 and rotationally driven by a motor 222.

Further, the reflecting mirror 201, the upper shaft bearing 217, and the lower shaft bearing 221 are attached to the device frame 22.
The reflecting mirror feeding mechanism 224, the upper shaft feeding mechanism 225, and the lower shaft feeding mechanism 226 fixed to the mirror 3 can be moved vertically independently by respective feeding screws.

Also, the inner side 227 of the reflecting mirror 201 has an O ring 22.
8, 229, 230, 231, and 232 to maintain airtightness from the outside air. Furthermore, the inside and outside of the reactor core tube 209 at the inner side 227 of the reflector are sealed with a cap 211 of the reactor core tube to prevent the reflector surface from being contaminated by gases generated from the sample or the like. Further, the reflecting mirror 201 includes a furnace core tube 209.
An atmospheric gas inlet 233 and an exhaust port 234 communicating with the inside of the sample are provided, so that the area around the sample can be covered with a predetermined atmospheric gas. Here, the seal in the cap 211 of the furnace tube does not have to be completely airtight as long as it can prevent the gas generated from the sample from reaching the reflecting mirror surface 202.

FIG. 4 is a partially sectional side view showing the operation of attaching and detaching the reactor core tube in the embodiment shown in FIG.
The attachment and detachment of the reactor core tube in the illustrated embodiment will be explained with reference to FIG. 4.

When attaching the reactor core tube, first open the opening/closing reflector 204 as shown in FIG. 4, and attach the upper sample 206 and lower sample 207 to the upper shaft 216 and lower shaft 220, respectively, through the opening window 236 of the reflector created at this time. Then, upper shaft 21
6 and the lower shaft 220 are moved up and down by the respective feed mechanisms 225 and 226, and the upper sample and the lower sample are positioned outside the space into which the reactor core tube is inserted. Next, lift the furnace tube holder 213 from the lever 214, insert the furnace tube into the reflector through the opening window 236, and clamp the furnace tube 209 with the furnace tube holder 213 by the pressing force of the compression coil spring 212 as shown in FIG. . For this reason, the length of the reactor core tube is made smaller than the reflector opening 236. Next, the positions of the upper sample 206 and the lower sample 207 are adjusted using the feed mechanisms 225 and 226 so that their opposing end surfaces are near the focal point F ₂ ', and the opening/closing reflector 2
04, preparation for sample melting is completed. In this state, if the thermal light source lamp 205 is turned on and the sample is heated, the upper and lower samples are joined together in the melting zone 208 where they are heated and melted, as shown in FIG.

When manufacturing a single crystal by the floating zone method, a seed crystal is used as the lower sample 207, a sintered bar of the same material is used as the upper sample 206, and the reflecting mirror 201 is moved by the reflecting mirror feeding mechanism 224. The crystal is grown on the seed crystal by gradually moving the seed crystal upward, resulting in the melting zone 208 gradually moving upward.

At the end of crystal growth, the upper sample is pulled upwards, the upper sample and the lower sample are separated in the melting zone, and the opening and closing reflector is opened by holding them for cooling.
Remove the reactor core tube and sample in the reverse order of installation.

Since the present invention has such a structure,
The upper and lower shafts only need to have enough movement to create space for the core tube to be installed, and the sum of the movement of the upper and lower shafts is the length L of the core tube plus the installation allowance and some margin. The value is sufficient.

Therefore, the height of the device is the total length S ₂ from the upper shaft to the lower shaft in Figure 3, the length L of the reactor core tube, a slight installation allowance α ₁ and a margin α ₂ , which is the height H ₂ = S ₂ +L+
It only requires α ₁ + α ₂ , which is much lower than in the conventional case. For example, when the height of the reactor core tube is 160 mm, the height can be reduced by about 750 mm compared to conventional equipment.

Furthermore, all operations for moving the upper and lower shafts can be performed using a switch (not shown) on the front of the device, and loading and unloading of the sample and the reactor core tube can all be performed through the opening window of the open reflector. All the work involved in attaching and detaching can be done at a convenient height in front of the device, and there is no need to take an unreasonable working posture at a low or high position unlike in the past.

Furthermore, since the work of fixing the reactor core tube is only by raising and lowering the lever of the reactor core tube holder, it is much simpler and more efficient than the conventional fixing work of the reactor core tube by tightening screws.

As described above, by implementing the present invention, the height of the equipment can be significantly reduced, and the operation of attaching and detaching the reactor core tube is simplified, and all attachment and detachment operations can be performed at a location in front of the equipment with a good working posture. This has the advantage of significantly improving work efficiency.

Although a single elliptical radiation heating device has been described here, the present invention is of course applicable to bielliptic and polyelliptic radiation heating devices.

FIG. 5 is a sectional view showing the periphery of a reflecting mirror of a bielliptic radiation heating device in which the present invention is applied, where 301 is a reflecting mirror, 302 is F ₁ ″,
303 is a reflecting mirror surface formed by a spheroid with focal points F _{2 '} ' and F ₃ ''; 304 is a fixed reflecting mirror;
5 is an openable/closeable reflector, 306 is an upper sample,
307 is a lower sample, 308 is a melting zone, 309 is a furnace tube, 310 is a furnace tube holder, 311 is an upper shaft, 312 is a lower shaft, and 313 and 314 are thermal light source lamps. This is the same as the embodiment shown in FIG.

Note that the thermal light source lamp 20 mentioned in the description of the embodiment
5, 313, and 314 may be any lamp that generates thermal radiation, such as a halogen lamp, a xenon lamp, a mercury lamp, or a tungsten lamp.

Furthermore, in the above explanation, the case where the radiation heating apparatus is applied to crystal growth using the floating zone method has been explained, but the radiation heating apparatus according to the present invention can be used for crystal growth other than the floating zone method (for example, epitaxial growth, etc.). ), and of course can also be used for melting samples, heating samples, etc.

[Brief explanation of drawings]

Figure 1 is a partial side view of the main part of a conventional example of a single elliptical radiation heating device, and Figure 2 is a partial side view of the main part of a conventional single elliptical radiation heating device.
Figure 3 is a partial side view showing the attachment and detachment operation of the reactor core tube in the conventional example, with the main part cut away;
FIG. 4 is a side view showing a cross-section of the main part of a single elliptical radiation heating device showing an embodiment, and FIG. FIG. 5 is a sectional view of the main parts of a bielliptic radiation heating device showing another embodiment of the present invention. In the figure, 101, 201, 301 are reflecting mirrors, 202, 302 are spheroidal reflecting mirror surfaces, 10
4,204,305 is an opening/closing reflector, 105,20
5,313,314 are thermal light sources, 106,206,
306 is the upper sample, 107, 207, 307 is the lower sample, 108, 208, 308 is the melting area, 10
9, 209, 309 are the core tubes, 213, 310 are the core tube holders, 216, 311 are the upper shafts, 2
20 and 312 are lower shafts, 223 is a main frame, 224 is a reflecting mirror feeding mechanism, 225 is an upper shaft feeding mechanism, and 226 is a lower shaft feeding mechanism.

Claims (1)

[Claims] 1. In a radiation heating device in which a thermal light source lamp is placed at one focus of a reflecting mirror consisting of one or more spheroidal surfaces, and the sample placed at the other focus is also heated by concentrating the light, A reactor core tube of a size that can be inserted through the opening window of the reflector that is created when the openable reflector is opened is pressed and held in the axial direction of the shaft inside the reflector by a reactor core tube holder, and the upper shaft with the sample mounted thereon. and a radiation heating device characterized in that the lower shaft is movable with the sample attached so that the upper and lower sample positions are at a height out of the space in which the reactor core tube is to be attached.