JPH0492884A - Device of pulling up single crystal - Google Patents

Abstract

PURPOSE:To reduce adhesion of SiO to an inner crucible and to continuously pull up single crystal for many hours in a device of feeding a Si raw material to gap between an inner and an outer crucible and successively pulling up single crystal by adopting specific constitution as the shape of the inner crucible. CONSTITUTION:In a device wherein an inner crucible 11 is arranged, a Si raw material 8 is fed 7 to gap between the inner 11 and an outer crucibles 1 and single crystal 6 is continuously pulled up, the inner crucible 11 comprises a cylindrical lower part and an upper part which is bent into a trumpet shape with a enlarge diamete on the top.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an apparatus for producing silicon single crystals as a functional electronic material.

[Prior Art] In silicon single crystal manufacturing, there is an apparatus that pulls a silicon single crystal while continuously supplying a solid raw material. It is known to use an inner crucible in order to prevent the solid raw material supplied at this time from precipitating on a single crystal and becoming polycrystallized before it is completely melted. For example, JP-A-63-303
In the No. 893 publication, as shown in FIG. 3, a silicon single crystal 35 is pulled while supplying a solid raw material 33 to a crucible 31 through a supply pipe 32, and the supplied raw material 33 is pulled up into a single crystal 3.
An inner crucible 36 is used to prevent precipitation on the surface of the molten metal.

[Problems to be Solved by the Invention] Such a conventional cylindrical shape of the inner crucible 36 impedes the flow of Ar gas in the furnace. As a result, the atmosphere in the furnace does not flow smoothly due to the arrangement of the inner crucible (and SiO is deposited on the inner crucible 36). If pulling is performed for a long time in such a state, the deposited and grown SiO will There is a problem in that the raw material 33 falls onto the surface of the melt 34 and causes polycrystallization of the single crystal 35. Also, scattering 38 of the raw material 33 is unavoidable.

In order to solve the above problems, the present invention provides a technique regarding an appropriate shape of the inner crucible.

[Means for Solving the Problems 1] In order to solve the above problems, the present invention has an inner crucible whose lower part is cylindrical and whose upper part is curved into a trumpet-like shape.
This allows r gas to flow smoothly to the outside of the inner crucible without stagnation.

[Operation] According to the present invention, since the shape of the inner crucible is curved outward in a trumpet-like shape at the upper part thereof, the Ar atmosphere in the furnace is smoothly moved from the inside in the radial direction to the outside of the crucible. flows.

As a result, SiO evaporated from the melt and carried by the Ar gas is discharged to the outside of the crucible without adhering to the inner crucible. Therefore, polycrystallization of the single crystal due to deposition of SiO and dropping to the liquid surface can be prevented, and continuous pulling of the single crystal for a long period of time has become possible.

[Example] Fig. 1 is a configuration diagram showing an example of an apparatus for pulling raw materials while continuously supplying them using an inner crucible according to the present invention. Moreover, FIG. 2 is a shape diagram of the inner crucible of the embodiment according to the present invention used in the configuration example of FIG. 1.

In FIG. 1, a crucible 1 is rotated by a rotating device 2, heated by a heater 3, and holds a melt 4.

The pulling wire 5 pulls up the single crystal 6 while growing it. The crucible 1 includes an inner crucible 11 according to an embodiment of the present invention.

Polycrystalline powder raw material silicon 8 is charged to the outside of inner crucible 11 through supply pipe 7 and melted. As shown in FIG. 2, this inner crucible 11 has a trumpet shape with a cylindrical lower part and an upwardly opened upper part. Its specific dimensions are shown in FIG. This inner crucible 11 is suspended from a hanging device 12.

Using the inner crucible 11 of the embodiment shown in FIG. 2 in an outer crucible 1 with a diameter of 18 inches (457 mm),
While rotating, raw materials were continuously supplied using the configuration shown in FIG. 1, and a silicon single crystal 6 having a diameter of 6 inches (150 mm) was pulled and produced.

In the example, the upper part of the inner crucible was curved outward to allow the Ar gas 13,14 to flow smoothly, thereby reducing the adhesion of SiO to the inner crucible. As a result, the time during which SiO can be pulled up until it is deposited, falls to the liquid surface, and polycrystallization of a single crystal occurs can be increased by 1.5 to 2.0 times compared to the conventional method.

In addition, it was possible to prevent the supplied raw materials and dust contained in the raw materials from entering the inner crucible, thereby preventing polycrystallization of the single crystal.

In addition, although the case where the inner crucible is suspended from above was explained in the above example, the present invention is not limited to this.
The inner and outer crucible may be integrated at the bottom.

[Effects of the Invention] The present invention provides a single-crystal Si manufacturing method in which an inner crucible is disposed, raw materials are supplied to the gap between the inner and outer crucibles, and the material is continuously pulled. Because I made sure that there was
The Ar gas in the furnace allowed the SiO in the middle of the inner crucible to be smoothly discharged to the outside of the crucible, reducing the adhesion of SiO to the inner crucible and making continuous pulling possible for a long time.

Furthermore, since the upper curved portion of the inner crucible covers the gap between the inner and outer crucibles for supplying raw materials, there is also the effect of preventing dust contained in the raw materials from entering the inner crucible and turning the single crystal into polycrystals.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus showing an example of pulling the raw material using the inner crucible according to the present invention, FIG. 2 is a schematic diagram of the inner crucible of the present invention shown in FIG. 1, and FIG. FIG. 2 is an explanatory diagram of an example of a method for pulling a single crystal while continuously supplying . 1... Crucible 2... Rotating device 3...
・Heater 4-... Melt 5... Pulling wire 6... Single crystal 7... Supply pipe
8... Polycrystalline raw material 11... Inner crucible
12... Hanging device 13, l4-A r

Claims (1)

[Claims] 1 In a single crystal pulling device that is equipped with an inner crucible and feeds raw materials into the gap between the inner and outer crucibles and continuously pulls the crystal, the inner crucible has a cylindrical lower part and a trumpet-shaped upper part with a curved diameter expansion. A single crystal pulling device characterized by: