JPH0416587A - Single crystal pulling up device - Google Patents

Abstract

PURPOSE:To improve a pulling up speed by forming the inside surface of an upper chamber to a shape to reflect and concentrate the radiation heat from a heater and a melt surface to a region where the melt surface and the inside surface of a crucible housing the melt come into contact. CONSTITUTION:The shape of the inside surface of the upper chamber 7 is formed to the shape to allow the reflection and concentration of the radiation heat 18 and 19 from the surface of the melt 12 and the heater 4 to the region 13 where the inside surface of the quartz crucible 1 and the surface of the melt 12 come into contact. The region 13 is locally subjected to heat insulation and the temp. of the melt 12 is maintained higher than the temp. at a crystal growth boundary 14. The melt 12 is, therefore, prevented from starting solidifying from the inside surface of the quartz crucible 1 even if the quantity of the heat that the melt 12 receives from the heater is decreased (is guided to the direction where the temp. over the entire part of the melt is lowered). The pulling up speed of a single crystal 11 is easily adjusted to a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a single crystal pulling device using the Czochralski method, and particularly to a device capable of pulling a single crystal ingot at high speed.

[Prior Art 1] As a single crystal growing apparatus, a single crystal pulling apparatus using the Czochralski method is known.

As a means for increasing the pulling speed in a single crystal pulling apparatus using the Czochralski method, an apparatus whose vertical cross-sectional view is shown in FIG. 4 is disclosed in Japanese Patent Publication No. 57-40119. In this device, a radiant screen 15 made of metal or a material with a metal surface capable of reflecting radiant heat is placed on top of a quartz crucible to surround a single crystal ingot (hereinafter simply referred to as single crystal) 11, and a heater 4 This device also blocks radiant heat from the surface of the melt 12 to the single crystal 11 to help cool the single crystal, promote single crystallization, and pull it up.

However, when pulling the single crystal 11 using the above-mentioned device, since the radiation screen 15 surrounds the single crystal 11, there is a problem that the radiation screen 15 comes into contact with the single crystal 11, and there are restrictions on the upper and lower limits of the position of the quartz crucible l. Therefore, there were operational problems such as the amount of raw material that could be charged was limited and the operating range was narrowed.

[Problems to be Solved by the Invention] The present invention provides a novel lifting device and attempts to solve the above-mentioned problems of the prior art by using a radiation scone.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a single crystal pulling apparatus using the Czochralski method, in which the upper chamber is
The unit has an inner surface shape capable of reflecting and concentrating radiant heat from a heater provided in the apparatus and a surface of the melt onto a region where the surface of the melt and the inner surface of a crucible containing the melt are in contact. A crystal pulling device is provided.

[Action J The present invention will be explained using the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the state of reflection of radiant heat in the apparatus shown in FIG. 1.

When growing a single crystal from the melt 12, the solidification rate, that is, the pulling rate, is determined by the heat dissipation from the crystal growth interface 14 minus the heat supply to the crystal growth interface 14. Specifically, from the heater 4 which is a heat supply source to the crystal growth interface 14
As the distance between the two points increases, the heat supply becomes smaller and the pulling speed can be increased.

However, pulling the crystal growth interface 14 upwards from the heat source means that the temperature of the other free surfaces of the melt 12 is also decreasing, and the inner surface of the quartz crucible 1 comes into contact with the surface of the melt 12. Solidification of the melt 12 begins in the region 13, inhibiting the growth of single crystals.

In the present invention, as shown in FIGS. 1 and 2, the inner surface shape of the upper chamber 7 is different from the surface of the melt 12 and the
By making the shape capable of reflecting and concentrating the radiant heat 18 and 19 from the quartz crucible onto the region 13 where the inner surface of the quartz crucible l and the surface of the melt 12 are in contact, the region 13 is locally kept warm and compared to the crystal growth interface 14. Thus, the temperature of the melt 12 can be kept high.

From this, even if the amount of heat that the melt I2 receives from the heater is reduced by raising the position of the quartz crucible 1, that is, the temperature of the entire melt is lowered, the melt 12 is removed from the inner surface of the quartz crucible 1. : Solidification does not start, and the pulling speed of the single crystal 11 can be easily increased.

The specific shape of the inner surface of the upper chamber 7 is not particularly limited as long as it satisfies the reflection conditions described above, and can be determined by taking into consideration the size of each part of the device. As the material, stainless steel, tungsten, molybdenum, etc. are preferably used.

The apparatus of the present invention can be used for growing single crystals of silicon, germanium, etc.

[Example J FIG. 1 is a longitudinal sectional view of an embodiment of the invention.

The design of the inner surface shape of the upper chamber 7 in this embodiment is as follows:
When 45 kg of polycrystalline silicon is charged into a quartz crucible with a diameter of 400 mm and a depth of 300 mm, the distance between the surface of the melt 12 and the upper end of the heater 4 after melting the raw material is 1.
The design was performed based on the position set to 00 mm. The above-mentioned inner surface shape is geometrically shaped so that the radiant heat 18 from the surface of the melt 12 is concentrated at the part where the quartz crucible l and the surface of the melt 12 are in contact, and the radiant heat 19 from the heater 4 is concentrated at the upper part of the quartz crucible l. I divided it scientifically.

Note that stainless steel was used as the reflective material.

A single crystal having a diameter of 6 inches was pulled using the apparatus configured as described above.

FIG. 3 is a diagram showing changes over time in the pulling rate when silicon single crystals are grown using the apparatus having the upper chamber 7 having the above-described configuration according to the present invention and the conventional apparatus (FIG. 4). It is.

Compared to conventional equipment, a higher pulling speed could be obtained by using the equipment of the present invention.

[Effects of the Invention] According to the present invention, single crystals such as silicon can be pulled at a higher speed than conventional equipment, and running costs can be reduced by eliminating the need for consumables such as radiation screens. It can also have a lowering effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the state of reflection of radiant heat, FIG. 3 is a diagram showing changes in pulling speed over time in the present invention and conventional equipment, and FIG. 4 is a vertical cross-sectional view of a conventional device. l-... Quartz crucible 2... Graphite crucible 3... Crucible support shaft 4... Heater 5... Insulating tube 6... Pulling shaft 7... Upper chamber 8... Gas rectifying tube 9... Argon gas inlet 10... Argon gas outlet 11... Single crystal 12... Melt 13... Region 14 where the inner surface of the quartz crucible is in contact with the melt surface
...Crystal growth interface 15...Radiation screen 16...Screen auxiliary stand 17...Screen support 18.19...Radiant heat

Claims (1)

[Scope of Claims] 1. In a single crystal pulling apparatus using the Czochralski method, an upper chamber receives radiant heat from a heater provided in the apparatus and the melt surface, and houses the melt surface and the melt. A single crystal pulling device characterized by having an inner surface shape that allows reflection to be concentrated in a region in contact with an inner surface of a crucible.