JPS63303886A - Silicon oxide discharge device in single crystal pulling-up device - Google Patents

Abstract

PURPOSE:To carry out a preferable single crystal silicon pulling-up operation without retaining the silicon oxide of high concn. on the inner peripheral wall of crucible by forming plural fins on the periphery of ring member in the silicon oxide discharge device. CONSTITUTION:The silicon oxide discharge device 10 is constituted in such a way that plural fins 12 is formed on the inner peripheral surface of an angular ring member 11 and an angular cap member 13 is projected to the side direction on the upper end part of the ring member 11. This silicon oxide discharge device 10 is fitted in the upper inner wall of crucible. The silicon oxide gas of high concn. positioned near the molten liquid surface of inner peripheral surface of crusible flows upwards from the crucible along the fins 12 of the silicon oxide discharge device 10 without retaining.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a silicon oxide discharge device in a silicon single crystal pulling device using the Czochralski method (CZ method).

[Conventional technology]

As shown in FIG. 3, the single crystal pulling device inserts a wire 4 (
(or pulling shaft) A seed crystal (not shown) attached to the seed crystal holder 7 at the lower end is immersed, a single crystal is formed by natural solidification, and the wire 4 is pulled up while rotating to grow the single crystal 5. It is something. The silicon in the crucible 2 is melted by the heat of the heater 1 provided around the crucible. A crucible shaft 6 supporting the crucible 2 is rotated by a motor or the like to prevent temperature non-uniformity in the molten silicon 3 within the crucible 2.

Incidentally, crucibles used in single crystal pulling apparatuses are generally made of quartz glass (SiO□). Therefore, the following chemical reaction occurs with the molten silicon 3, and silicon oxide (SiOx) gas harmful to crystal growth evaporates from the molten liquid surface.
□ S i Oz + S i 4 S i Ox +
O! Therefore, in order to discharge such harmful gases to the outside of the pulling furnace A, an inert gas 8 such as argon gas is introduced from the upper part of the furnace as shown in FIG.

[Problem that the invention seeks to solve]

Figures 5 to 8 show the flow of silicon oxide gas when inert gas is introduced, and Figure 5 shows the flow of silicon oxide gas when inert gas is introduced.
．． After 2 seconds, Figure 6 after 0.4 seconds, Figure 7 after 0.6 seconds,
FIG. 8 shows the state after 1.0 seconds.

Even if the inert gas is introduced as shown, the silicon oxide gas 9 near the molten liquid surface around the inner wall of the crucible 2 does not flow downward and stagnates (see FIG. 4). Since the stagnant silicon oxide gas 9 has a high concentration (50%), there is a problem that dislocations occur in the silicon single crystal during the crystal pulling operation.

For this reason, as shown in JP-A-61-44792, it is conceivable to form a plurality of gaps above the melt surface on the side wall of the crucible, but it is extremely difficult to form holes in the crucible, that is, in the quartz glass. Have difficulty.

This invention was created to solve the above problems, and provides a silicon oxide discharge device in a single crystal pulling device that does not cause stagnation of silicon oxide gas and does not require cutting or the like on the crucible. The purpose is to

[Means for solving the problem] The silicon oxide discharge device in the single crystal pulling device of the present invention is attached around the upper end of the inner wall of the crucible, and has a plurality of fins formed around an annular ring member. It is characterized by:

〔Example〕

The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 shows an embodiment of a silicon oxide discharge device 10 of the present invention.

The silicon oxide discharge device 10 includes an annular ring member 11
A plurality of fins 12 are formed on the inner peripheral surface of the ring member 11, and a ring-shaped cap member 13 is provided at the upper end of the ring member 11 so as to protrude laterally. The ring member 11, fin 12, and cap member 13 forming the silicon oxide discharge device 10 have sufficient heat resistance and are integrally molded. The outer diameter of the ring member 11 is relative to the inner diameter of the upper part of the crucible 2.
Form it so that it has a slight tight fit.

In addition to the illustrated embodiment, a plurality of fins may be formed on the outer peripheral surface of the ring member. In this case, the ring member is provided with a plurality of holes, and a cap member is not provided. A plurality of holes are bored in the same way as in the ring member.

The silicon oxide discharge device 10 formed as described above is
As shown in the figure, it is fitted onto the upper inner wall of the crucible 2.

Since the crucible 2 rotates as described in the prior art, the highly concentrated silicon oxide gas located near the molten liquid surface around the inner wall of the crucible 2 flows upward to the crucible 2 along the fins 12 of the silicon oxide discharge device 10. , never stagnate.

〔Effect of the invention〕

■ Highly concentrated silicon oxide does not stagnate around the inner wall of the crucible, making it possible to pull single crystals smoothly.

■ There is no need to perform cutting on the crucible (it is easy to manufacture and inexpensive.

■ Can be easily attached to ready-made crucibles.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the silicon oxide discharge device of the present invention, FIG. 2 is a sectional view showing an example of use, FIG. 3 is a sectional view showing a pulling furnace of a conventional single crystal pulling device, and FIG. FIG. 4 is an enlarged view of the main part of FIG. 3 showing the flow of inert gas, and FIGS. 5 to 8 are enlarged views of the main part showing the flow of silicon oxide gas. A... Drawing furnace, 1... Heater, 2.
...crucible, 3...molten silicon, 4.
...Wire, 5...Single crystal, 6...
... Crucible axis, 7 ... Seed crystal holder, 8 ...
...Inert gas, 9...Silicon oxide gas, 10...Silicon oxide discharge device, 11...
Ring member, 12...fin, 13...
Cap member Fig. 3 Fig. 4 (Fig. 5 Fig. 6)

Claims (1)

[Claims] 1. A silicon oxide discharge device in a single crystal pulling device, which is attached around the upper end of an inner wall of a crucible, and is characterized by having a plurality of fins formed around an annular ring member.