JPH03215382A - Producing device of crystal - Google Patents

Abstract

PURPOSE:To enable to uniform crystal growth without defect by providing heat sources at first foci and a crystalline raw material at a second focus in spheroidal reflectors and controlling an electric power supplying to the heat sources with a controller according to a measured energy of heat rays. CONSTITUTION:Heat sources 107 and 107' are provided at first focus parts and a crystalline raw material 101 is provided at a second focus part in spheroidal reflectors 100 and 100'. Said raw material 101 is fixed at top ends of rotatable shafts 105 and 106 and heat rays from said heat sources 107 and 107' are concentrated to the raw material 101. Energy of said heat rays is measured by brightness detectors 111 and 111' and a measured value for a rotation of the shafts is memorized. Then, an electric power supplied to the heat sources 107 and 107' is controlled by lamp controllers 114 and 114' so as the memorized value to attain a previously set value, thus uniform crystal without defect is grown.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a crystal manufacturing apparatus used for crystal growth, etc.
In particular, it relates to a crystal manufacturing apparatus using the fused zone method.

[Conventional technology]

A crystal manufacturing device places a heat source at the first focal point of a reflecting mirror made of a spheroidal surface, places a crystal material at the second focal point, concentrates the infrared rays, and heats and melts the crystal material to grow the crystal. It is something to do. This device includes a single ellipsoid type in which the reflecting mirror is composed of only one spheroidal surface, a bielliptic type in which the reflecting mirror is composed of a combination of two spheroidal surfaces and shares a second focal point, Furthermore, there is a multi-ellipsoid type in which the reflecting mirror is composed of a combination of three or more spheroidal surfaces and shares a second focal point.

Next, a conventional crystal manufacturing apparatus will be explained with reference to the drawings.

FIG. 2 is an explanatory diagram showing a cross section of a heating furnace portion of a crystal manufacturing apparatus having a conventional structure and a block diagram of a heat source control system disclosed in Japanese Patent Application Laid-Open No. 58-181094.

In the figure, 200 and 200' are spheroidal reflectors, 2
01 is a polycrystalline material, and 202 is a single crystalline material. These crystalline materials are attached to an upper shaft 205 and a lower shaft 206 by an upper chuck 203 and a lower chuck 204, respectively, and supply power to heat sources 207 and 207', such as xenon lamps or halogen lamps, and draw electricity from the heat source 207. When infrared rays are generated, a molten zone 208 is formed between the polycrystalline material 201 and the single crystal material 202, that is, at the second focal point of the crystal manufacturing apparatus. 20
Reference numeral 9 denotes a furnace for protecting the spheroidal reflector from gas generated from the polycrystalline material 201 and the single-crystalline material 202, and for creating a vacuum around the polycrystalline material 201 and the single-crystalline material 202 or filling them with inert gas or the like. It is a core tube. 210 and 2l
O' is a window opened in the spheroidal reflecting mirrors 200 and 200', respectively, and numbers C 211 and 211' are brightness detection elements such as photodiodes. Also 2
12 and 212' are amplifier circuits that amplify the outputs of the brightness detection elements 211 and 211', respectively, and also include a conversion circuit to voltage output when the brightness detection elements 211 and 211' are of current output type. 213 and 213' are heat source controllers and brightness detection elements 2+1 and 211, respectively.
The brightness of the heat sources 207 and 207' matches the brightness setting value set in advance by receiving the signal from the heat source 207 and 207' through the amplifier circuits 212 and 212' and comparing it with the brightness setting value input separately. As heat sources 207 and 20
This is a controller that independently controls the power supplied to 7'.

Crystal growth is carried out in the molten zone 208 by a moving mechanism (not shown).
is performed by moving in the direction of the polycrystalline material 201, that is, by moving the spheroidal reflecting mirrors 200 and 200' in the direction of the polycrystalline material 20+. Rotating mechanisms (not shown) respectively attached to the upper shaft 205 and the lower shaft 206 rotate the polycrystalline material 201 and the single crystal material 20 through the chucks 203 and 204.
2 is rotated and the melting zone 208 is also rotated to make the temperature distribution of the melting zone 208 uniform in the circumferential direction.
This is a mechanism for stirring inside the 08. Crystal growth usually takes a long time, from 1 to 10 days, but even if the brightness of the heat source may gradually decrease during this time, the brightness of the heat source is maintained at the brightness at the start of crystal growth. controlled by.

(Problem to be Solved by the Invention) However, if the shape of the single crystal material and polycrystalline material is an axially symmetrical cylinder, the light energy from the heat source reflected on the surface of these materials will always be constant; In some cases, monocrystalline and polycrystalline materials with corners are used, such as those shown in Figure 1. In this case, as the shaft rotates, the infrared light energy from the heat source measured by the brightness detection element is synchronized with the rotation. In addition to single-crystal materials and polycrystalline materials, chucks that are not axially symmetrical are also used, and in these cases, the brightness detection element is also used in synchronization with the rotation of the shaft. The infrared light energy from the heat source being measured was becoming stronger or weaker.In this way, the infrared light energy from the heat source measured by the brightness detection element changes, but the controller does not detect the brightness. Since the power supplied to the heat source is controlled so that the infrared light energy from the heat source measured by the element remains constant, the size of the molten zone also changes, which can lead to crystal defects.

The purpose of the present invention is to eliminate such conventional drawbacks, and to provide a crystal manufacturing apparatus in which the power supplied to the heat source is constant and crystal defects do not occur even when the shapes of single crystal materials, polycrystal materials, and chucks are not axially symmetrical. Our goal is to provide the following.

[Means for Solving the Problem] In order to achieve the above object, in the crystal manufacturing apparatus according to the present invention, a heat source is provided at the first focal point of the spheroidal reflecting mirror movable by a moving mechanism, and the spheroidal reflector is provided with a heat source. A crystal material attached to the tip of a rotatable shaft is provided at the second focal point of the reflecting mirror, infrared rays emitted from the heat source are concentrated on the crystal material, and the optical energy of the infrared rays is measured by a brightness detection element. , a crystal manufacturing apparatus using a fused zone method that controls electric power supplied to a heat source according to the amount of infrared rays to melt the crystal material and grow the crystal, wherein the brightness is detected during one rotation of the shaft; It has a memory that records measured values in the element, and a controller that controls the power supplied to the corresponding heat source so that the measured value recorded in the memory becomes a preset value.

Further, in the crystal manufacturing apparatus according to the present invention, the memory records the measured value of the brightness detection element during one revolution of the shaft, and the controller controls the heat source according to the minimum value of the measured values recorded in the memory. It has the function of controlling the supplied power. Further, in the crystal manufacturing apparatus according to the present invention, the measured value of the brightness detection element during one rotation of the shaft is recorded in a memory, and the controller controls the heat source according to the average value of the measured values recorded in the memory. It has the function of controlling the supplied power.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram showing a cross section of a heating furnace portion of a crystal manufacturing apparatus according to an embodiment of the present invention and a block diagram of a heat source control system.

In the figure, 100 and 100' are spheroidal reflectors, 1
01 is a polycrystalline material, and 102 is a single crystalline material. These crystal materials are attached to the upper shaft 105 and the lower shaft +06 by the upper chuck 103 and the lower chuck +04, respectively, and supply power to heat sources 107 and 107' such as xenon lamps or halogen lamps, and heat sources +07 When infrared rays are generated from the infrared rays, a molten zone +08 is formed between the polycrystalline material 101 and the single crystal material 102, that is, at the second focal point of the crystal manufacturing apparatus. 10
9 is a furnace for protecting the spheroidal reflector from gas generated from the polycrystalline material +01 and the single-crystalline material +02, and for creating a vacuum around the polycrystalline material 101 and the single-crystalline material +02 or filling it with inert gas, etc. It is a core tube. 110 and +1
0' is a window opened in the spheroidal reflector +00 and too', respectively, and Ill and Ill' are brightness detection elements such as photodiodes. Also 1
12 and 112' are amplifier circuits that amplify the outputs of the brightness detection elements +11 and Ill', respectively, and also include a conversion circuit to voltage output when the brightness detection elements Ill and Ill' are of current output type. +13 and ll3' are memory circuits, and the signals from the brightness detecting elements Ill and 111' during one rotation of the shaft 106 are amplified by an amplifying circuit +1.
2 and 112', this is recorded, and the minimum value and average value are output. 114 and 1
14' is a heat source controller that connects memory circuits 113 and 1;
By receiving the output from 13' and comparing it with the brightness setting value input separately, the heat source 107 is adjusted so that the brightness of the heat sources 107 and 107' matches the preset brightness setting value.
and 107' are controllers that independently control the power supplied to the controllers 107' and 107'.

Crystal growth is carried out in the molten zone 108 by a moving mechanism (not shown).
is performed by moving in the direction of the polycrystalline material lot, that is, by moving the spheroidal reflectors 100 and 100' in the direction of the polycrystalline material lot. A rotating mechanism (
(not shown) rotates the polycrystalline material lot and the single crystal material 102 through the chuck 103 and the chuck 104, and also rotates the melting zone 108 to make the temperature distribution in the circumferential direction of the melting zone 108 uniform. Stir inside 108. In the present invention, the controllers 114, 11
4' is the measurement value output from the memories 113, 113', that is, the minimum value of the measurement value during one rotation of the light energy shaft in the brightness detection element, or the one rotation of the light energy shaft in the brightness detection element. The heat source is controlled based on the average value of the measured values.

Although this article has explained a type of crystal growth apparatus that grows crystals by moving a spheroidal reflector, this book also describes a type of crystal growth apparatus that grows crystals by moving a shaft to which a crystal material is attached. The invention can be practiced similarly. Furthermore, although a bielliptic crystal manufacturing apparatus has been described here, the present invention can be implemented in the same manner with a monoelliptic or polyelliptic crystal manufacturing apparatus.

Further, as the heat source mentioned in the above explanation, the present invention can be similarly implemented using any heat source such as a xenon lamp or a halogen lamp.

〔Effect of the invention〕

According to the crystal manufacturing apparatus according to the present invention, the shapes of the single crystal material, the polycrystalline material, and the chuck are not axially symmetrical, and the heat source is reflected from the surfaces of the single crystal material, the polycrystalline material, and the chuck and detected by the brightness detection element. Even if there is infrared light energy of Since the heat source is controlled by the minimum value, the power supplied to the heat source is stable, eliminating defects in the resulting crystal, and making it possible to obtain a uniform single crystal. In addition, the shapes of the single crystal material, polycrystalline material, and chuck are not axially symmetrical, and the infrared light energy from the heat source reflected by the surfaces of the single crystal material, polycrystalline material, and chuck and detected by the brightness detection element changes. By controlling the heat source using the average value measured during one revolution of the light energy shaft in the brightness detection element, the power supplied to the heat source is stabilized, and no defects occur in the resulting crystal. It becomes possible to obtain a uniform single crystal.

Regarding the control method, it is clear that the same effect can be obtained even if the control of the power supplied to the heat source is replaced with voltage control or current control.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a cross section of a heating furnace portion of a crystal manufacturing apparatus according to an embodiment of the present invention and a block diagram of a heat source control system, and FIG. 2 is a cross section of a heating furnace portion of a conventional crystal manufacturing apparatus. FIG. 2 is an explanatory diagram showing a block diagram of a control system for a heat source. 100, 100', 200, 200'...Spheroidal reflecting mirror 107, 107', 207, 207'...Heat source 108, 208...Melting zone Ill, 111
', 211, 211'...brightness detection element 112,
112', 212, 212'...Amplification circuit 113,
113'...Memory circuit

Claims (3)

[Claims] (1) The first spheroidal reflector that can be moved by a moving mechanism
A heat source is provided at the focal point of the spheroidal reflector, a crystal material attached to the tip of a rotatable shaft is provided at the second focal point of the spheroidal reflector, and the infrared rays emitted from the heat source are concentrated on the crystal material, thereby increasing the brightness. A crystal manufacturing apparatus using a fused zone method in which the optical energy of the infrared rays is measured by a detection element, the electric power supplied to the heat source is controlled according to the amount of infrared rays, and the crystal material is melted to grow the crystal, comprising: A memory for recording the measured value of the brightness detection element during one revolution of the shaft, and control of electric power supplied to the corresponding heat source so that the measured value recorded in the memory becomes a preset value. 1. A crystal manufacturing apparatus characterized by having a controller for performing the operation. (2) The memory records the measured value of the brightness detection element during one revolution of the shaft, and the controller has a function of controlling the power supplied to the heat source based on the minimum value of the measured values recorded in the memory. The crystal manufacturing apparatus according to claim 1, further comprising: (3) The controller has a function of recording the measured value of the brightness detection element during one rotation of the shaft in a memory, and controlling the electric power supplied to the heat source based on the average value of the measured values recorded in the memory. The crystal manufacturing apparatus according to claim 1, further comprising: