JP3386167B2 - Single crystal growth equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single crystal growing apparatus using the Bridgman method or the like. A single crystal growth apparatus using the Bridgman method stores a molten material in a crucible, moves it from a high temperature side to a low temperature side in a furnace having an appropriate temperature distribution, and melts the raw material. Is a device for growing a single crystal by gradually solidifying.
Conventionally, such a single crystal growth apparatus is provided with a seismic device 10 on a floor 8 as shown in FIG. 3, for example, and the entire single crystal growth device 20 is placed on the seismic device 10 to remove the ground. The effect of vibration is removed. [0003] However, since the single crystal growth apparatus is long vertically, even if a seismic device is provided at the lower end thereof,
In an important crystal growth part, there is a problem that the influence of vibration cannot be avoided. According to the investigation by the present inventors, in a crystal growth apparatus installed on a laboratory floor, an acceleration level of 40 to 5 was obtained.
The vibration of 0 dB was measured, and it was found that the vibration increased further when the peripheral machinery and the like operated. Further, at a position 2 m above the lower end of the crystal growth apparatus, 50 to 55
A dB acceleration level has been detected. The position 2 m above the lower end substantially corresponds to the solid-liquid interface level of single crystal growth in the Bridgman single crystal growth apparatus. The present invention prevents the most important vibration of the solid-liquid interface of a vertically long apparatus for growing a single crystal from such a molten raw material, and produces a uniform single crystal without being affected by the vibration. It is an object to provide a single crystal growth apparatus. SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems, and its technical means is to provide an apparatus for growing a single crystal from a molten raw material at a solid-liquid interface level. A single crystal growth apparatus characterized by having a support structure in which a support portion of the apparatus is provided at a height of 1 m or less from above and below, and the support section is mounted on an upper surface of the seismic device. In this apparatus, the position of the supporting portion is more preferably at a height within 0.5 m above and below the solid-liquid interface level, and it is more preferable to further reduce the difference in height. Should be matched. In the apparatus of the present invention, a support is provided at a position close to the solid-liquid interface for growing a single crystal, and the support is supported via an earthquake-resistant device. Or it becomes the vicinity thereof. Therefore, the acceleration of vibration is minimized at the most important crystal growth interface. It is preferable that the height of the support portion and the height of the solid-liquid interface be as close as possible, and ideally, they should be completely coincident. However, in practice, it is not necessary to set the height so strictly. On the other hand, if the height position with respect to the support portion is within 1 m vertically, the desired effect can be achieved,
More preferably, it is good to be within 0.5 m above and below. As the seismic device, an air spring, an oil damper, a magnetic levitation device, or the like is used. A two-dimensional seismic device for horizontal movement may be used, but a three-dimensional seismic device may be used. In addition, as for the vibration isolation level, a countermeasure against microvibrations of 25 to 100 Hz is usually easy, and the apparatus of the present invention is a seismic device corresponding to a weak ground motion of 0 to 10 Hz, which is generally considered to be difficult. And corresponds to seismic intensity 5 (80 to 250 gal). FIG. 1 is a side view of a single crystal growth apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. This device is a crucible 1
This is a device in which a molten raw material 2 is housed in a furnace, and is moved downward in a furnace 4 having a temperature gradient by a heater 3, and a seed crystal is arranged at a lower end of the crucible 1 to grow a single crystal 5. In the apparatus of the present invention, four support portions 6 are provided at heights substantially coincident with the solid-liquid interface 7, and are supported on a frame 9 erected from a floor 8 via an earthquake-resistant device 10. did. Since the harmful vibration in the single crystal growth apparatus is mainly horizontal vibration, a two-dimensional seismic apparatus was used as the seismic apparatus 10. FIG. 4 shows the vibration acceleration at the solid-liquid interface level in the example of the present invention in comparison with the conventional example. In FIG. 4, A is on the floor of the conventional example in which a seismic device is provided at the lower end of the single crystal apparatus, B is about 2 m above the lower end of the apparatus of the conventional example, C is the solid-liquid interface level of the example, and D is about 1 m. It is a measured value of each vibration acceleration at the solid-liquid interface level of the example when the vibration mill at a remote position is operated. In the example, the vibration acceleration was 28 to 32 dB, and was not affected even if artificial vibration occurred within 1 m. E in FIG. 4 is the data of the vibration acceleration at the solid-liquid interface level of the embodiment device when an earthquake of seismic intensity 3 accidentally occurred. In the apparatus of the embodiment, even if there is an earthquake with a seismic intensity of about 3, the crystal growth can be continued without abnormality. Since the single crystal growth apparatus of the present invention is constructed as described above, vibration at the solid-liquid interface can be significantly reduced, and artificial vibration is generated within 1 m of the apparatus. However, it was not affected, and excellent crystal growth could be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing a single crystal growth apparatus according to an embodiment of the present invention. FIG. 2 is a plan view showing a single crystal growth apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing a conventional single crystal growth apparatus. FIG. 4 is a graph showing the effect of the present invention. [Description of Signs] 1 crucible 2 molten material 3 heater 4 furnace 5 single crystal 6 support 7 solid-liquid interface 8 floor 9 frame 10 seismic device

Claims (1)

(57) [Claim 1] In a device for growing a single crystal from a molten raw material, a support portion of the device is provided at a height within 1 m above and below the solid-liquid interface level, and the support portion is provided. A single crystal growth apparatus mounted on an upper surface of a seismic device.