JPH0728964U - Single crystal growth equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a single crystal growth apparatus capable of easily separating a radiation screen from an upper chamber wall. A radiation screen is arranged around a single crystal to be grown and above a molten liquid surface as a raw material, and the upper edge of the radiation screen is brought into contact with an upper chamber wall, and the upper end of the radiation screen is In a single crystal growth apparatus sandwiched by a plurality of holding members fixed to the upper chamber wall, at least one or more of the plurality of holding members is fixed to the upper chamber wall, and the fixing device. The single crystal growth apparatus comprises a holder provided so as to be movable relative to the upper chamber wall and the holder holds the upper end of the radiation screen between the holder and the upper chamber wall.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a single crystal growth apparatus used in the Czochralski method.

[0002]

[Prior art]

 In this type of single crystal growth apparatus, conventionally, a single crystal is grown around a single crystal for various purposes such as accelerating single crystallization, increasing the pulling rate, and suppressing the carbon concentration in the single crystal. A radiant screen is provided.

For example, in Japanese Examined Patent Publication No. 57-40119 (the mounting structure of the radiation screen is schematically shown in FIG. 7) and Japanese Patent Laid-Open No. 62-138386 (not shown), the radiation screen is provided through a plurality of components. 21 is attached to the bottom of the chamber 22. Further, in Japanese Patent Publication No. 62-138384, as shown in FIG. 8, a flange portion 23 is bent at the upper edge of the radiation screen 21, and the flange portion 23 is hooked on the upper opening 24 of the chamber 22. ing.

Among the conventional single crystal growth apparatuses described in JP-B-57-40119 and JP-A-62-138386, it is difficult to manufacture the radiation screen 21 due to the large number of parts, and the chamber 22 Since the radiation screen 21 is attached to the lower part of the furnace, the radiation screen 21 must be attached or detached each time when the furnace is assembled and disassembled.

Further, in the radiation screen described in Japanese Patent Laid-Open No. 62-138384, it is difficult to form the flange portion 23, and the size of the radiation screen 21 is limited by the size of the top opening 24 of the chamber 22. There is a problem that

Therefore, the present inventors have previously provided a single crystal growth apparatus capable of solving the above-mentioned problems. As shown in FIGS. 7 and 8, the improved single crystal growth apparatus is a single crystal growth apparatus in which a radiation screen 9 is disposed above the melt surface, and the upper edge of the radiation screen 9 is located at the upper chamber wall 1a. And the upper end of the radiation screen 9 is held by a plurality of holding members 11, 11 fixed to the upper chamber wall 1a. Since the radiation screen 9 is attached to the upper chamber wall 1a via the holding members 11 and 11 in the single crystal growth apparatus having the above-described structure, the radiation screens of various sizes are irrespective of the size of the upper opening of the chamber. The radiant screen attached to the upper chamber wall is integrated with the upper chamber wall, so that when the furnace is assembled and disassembled, the radiant screen also moves together with the upper chamber wall attached and detached. This has the advantage of eliminating the work of attaching and removing the radiation screen itself.

More specifically, in FIG. 7, reference numeral 1 denotes a chamber in which a shaft 2 which rotates and moves up and down and a pedestal 3 fixed to the shaft 2 are arranged. A quartz crucible 4 is placed on the pedestal 3. Reference numeral 5 denotes a heater arranged on the outer circumference of the quartz crucible 4, 6 denotes a single crystal, and 7 denotes a wire having a seed crystal 8 attached to its lower end. 1b is a viewing window.

Reference numeral 9 denotes a substantially frustoconical cylindrical radiation screen attached to the upper chamber wall 1a of the chamber 1 by a bolt 10, and as shown in FIG. 8, four holding members 11 are arranged at 90 °. The holding members 11 hold the upper end of the radiating screen 9 in a horizontal direction at intervals. Each holding member 11 is formed with a long hole 11a for inserting the shaft of the bolt 10 for fixing the member 11 to the upper chamber wall 1a.

As described above, the single crystal growth apparatus is characterized in that the radiant screen 9 is attached to the upper chamber wall 1a of the chamber 1 via the holding member 11, and the radiant screen 9 is attached to the upper chamber wall 1a of the chamber 1. The radiation screen 9 used inevitably has a large height L. Here, regarding the height L of the radiant screen 9, when the height L is 250 mm A and when it is 350 mm B, the temperature distribution in the furnace and the oxygen concentration distribution in the single crystal are described below. It is as follows.

FIG. 9 shows the investigation result of the temperature distribution. When the height L is large B, the high temperature is maintained by the secondary radiation of the radiant screen 9 even in the portion far from the liquid surface, and the single crystal trap is generated. The heat history between the tail and tail was made uniform.

The homogenization of the thermal history should be reflected in the oxygen concentration distribution in the single crystal. FIG. 10 shows the examination result (Δ [Oi] evaluation) of the oxygen concentration distribution.

That is, FIG. 10 shows each part in the longitudinal direction of the single crystal on the horizontal axis and the Δ [Oi] value on the vertical axis.

Δ [Oi] = Δ [Oi] ^I −Δ [Oi] ^N (Δ [Oi] I: [Oi] value before heat treatment) (Δ [Oi] N: [Oi] value after heat treatment) Heat treatment condition: 800 ° C. × 4 Hr + 1,000 ° C. × 16 Hr FIG. 10 shows that when the height L is large, B has more uniform portions of Δ [Oi] distribution. That is, the height L is increased by mounting the radiant screen 9 on the upper chamber wall 1a, which makes the heat uniform (and thus the oxygen concentration distribution uniform), and the quality of the single crystal is long. It has the advantage of being uniform in direction, and there are no problems.

[0014]

[Problems to be solved by the device]

 Thus, the previously proposed single crystal growth apparatus is one in which the upper end of the radiation screen is held by the plurality of holding members that are fixed to the upper chamber wall, and the radiation screen is attached to the upper chamber wall of the chamber. Radiation screens of various sizes can be used regardless of the size of the upper opening of the chamber. The radiation screen attached to the upper chamber wall here is integrated with the upper chamber wall. In this case, there was an advantage that the work of assembling and dismantling the furnace became easy because the work of mounting and removing the radiation screen itself became unnecessary.

However, when the furnace is assembled and disassembled without removing the upper chamber wall, the apparatus has a problem that it takes time to separate the radiation screen from the upper chamber wall.

Accordingly, the present invention has an object of proposing a single crystal growth apparatus capable of easily separating the radiation screen from the upper chamber wall while having the advantages of the previously proposed single crystal growth apparatus. And

[0017]

[Means for Solving the Problems]

 According to the present invention, a radiant screen is arranged around the single crystal to be grown and above the molten liquid surface as a raw material, and the upper edge of the radiant screen is brought into contact with the upper chamber wall. In a single crystal growth apparatus having an upper end held by a plurality of holding members fixed to the upper chamber wall, at least one of the plurality of holding members is a fixture fixed to the upper chamber wall. A single crystal growth apparatus comprising a holder provided so as to be movable with respect to the fixture, and holding the upper end of the radiation screen between the holder and the upper chamber wall by the holder.

[0018]

[Action]

 The radiant screen is held by the plurality of holding members with its upper edge abutting against the upper chamber wall. When the radiation screen is to be removed from the upper chamber wall as necessary, the holder of the holding member is moved with respect to the fixture, and the holder is separated from the radiation screen. At this time, since the fixing member of the holding member is fixed to the upper chamber wall, the holding member itself does not have to be removed from the upper chamber wall.

[0019]

【Example】

 In the present invention, the single crystal growth apparatus is basically the same as that described above. That is, as shown in FIG. 7, a shaft 2 that rotates and moves vertically and a pedestal 3 fixed to the shaft 2 are arranged in a chamber 1, and a quartz crucible 4 is mounted on the pedestal 3. It has been placed. Reference numeral 5 is a heater, 6 is a single crystal, 7 is a wire having a seed crystal 8 attached to its lower end, and 1b is a viewing window.

In FIG. 1, a radiation screen 9 is attached to the upper chamber wall 1a of the chamber 1 with bolts 10. Like the previous example, four holding members 11 are horizontally arranged at 90 ° intervals. Then, the holding member 11 holds the upper end of the radiation screen 9. Each holding member 11 is formed with a long hole 11a for inserting the shaft of the bolt 10 for fixing the member 11 to the upper chamber wall 1a.

According to the present invention, at least one of the plurality of holding members 11 is provided so as to be movable with respect to the fixture 11b fixed to the upper chamber wall 1a and the fixture 11b. The holding tool 11c holds the upper end of the radiation screen 9 between the holding tool 11c and the upper chamber wall 1a.

As shown in FIGS. 2 and 3, the holding member 11 including the fixing tool 11b and the holding tool 11c is configured so that the holding tool 11c rotates about a shaft 11d of the fixing tool 11b as a fulcrum. The tip 11e of the holder 11c has a tapered surface so that the upper end of the radiation screen 9 can be held.

The holding member 11 shown in FIG. 4 relates to another embodiment, and in this case, the holding tool 11c can be slid with respect to the fixing tool 11b.

The holding member 11 used in the present invention, especially the holding member 11 including the fixing tool 11b and the holding tool 11c, is not limited to the one shown in the figure, and the holding tool 11c is provided so as to be movable with respect to the fixing tool 11b. The structure may be arbitrary as long as it has

[0025]

As described above, according to the present invention, in the single crystal growth apparatus in which the radiation screen is arranged above the melt surface, the upper end of the radiation screen is fixed by the plurality of holding members fixed to the upper chamber wall. And the radiant screen is attached to the upper chamber wall of the chamber. Therefore, radiant screens of various sizes can be used regardless of the size of the upper opening of the chamber.

Further, according to the present invention, at least one of the plurality of holding members is provided with a fixture fixed to the upper chamber wall and a holder movably provided with respect to the fixture. The holding tool holds the upper end of the radiation screen between the upper chamber wall and the upper chamber wall, so that the holding tool is moved with respect to the fixing tool and the holding tool is detached from the radiation screen. The radiation screen can be easily separated from the chamber wall. According to the present invention, the fixing member is fixed to the upper chamber wall, and the holding member itself is removed when the radiation screen is removed. Since it does not have to be removed from the chamber wall, the work of attaching and removing the radiation screen can be performed extremely easily.

[Brief description of drawings]

FIG. 1 is a perspective view of a radiation screen using a holding member according to the present invention.

FIG. 2 is a perspective view of a holding member used in the present invention.

FIG. 3 is a perspective view of a holding member used in the present invention.

FIG. 4 is a perspective view of a holding member used in the present invention.

FIG. 5 is a vertical cross-sectional view of a conventional device.

FIG. 6 is a vertical cross-sectional view of a conventional device.

FIG. 7 is a vertical sectional view of the previously proposed device.

FIG. 8 is a perspective view of a radiation screen using the previously proposed holding member.

FIG. 9 is a graph showing the influence of the radiation screen on the temperature distribution in the furnace.

FIG. 10 is a graph showing the influence of the radiation screen on the oxygen concentration distribution.

[Explanation of symbols]

 1 Chamber 1a Upper chamber wall 9 Radiation screen 11 Holding member 11b Fixing tool 11c Holding tool

Claims (1)

[Scope of utility model registration request] 1. A radiant screen is arranged around a single crystal to be grown and above a molten liquid surface as a raw material, and an upper end edge of the radiant screen is brought into contact with an upper chamber wall, and an upper end of the radiant screen is provided. In a single crystal growth apparatus sandwiched by a plurality of holding members fixed to the upper chamber wall, wherein at least one of the plurality of holding members is
It is composed of a fixture fixed to the upper chamber wall and a holder movably provided with respect to the fixture, and the upper end of the radiation screen is held between the holder and the upper chamber wall by the holder. A single crystal growth apparatus characterized by the above.