JPH0412000B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrode structure for mechanically supporting a heating resistor and supplying current in an apparatus for manufacturing single crystals of Si, GaP, GaAs, etc. Regarding.

[Conventional technology]

When producing a single crystal of Si, GaP, GaAs, etc. in a crucible placed in an airtight container, a resistance heating method is generally used in which a resistor made of high-purity graphite is used as a heating source. This heating resistor is placed close to the crucible within the airtight container, and an electrode device is provided through the airtight container for mechanical support and electrical connection of the heating resistor. The first condition required for this electrode structure is to supply a stable current for a long period of time to the heating resistor placed inside the airtight container. In particular, with the increase in diameter and capacity of single crystals,
It is required to stably supply a large current without causing poor contact or poor insulation. Second, since the heating resistor requires disassembly and assembly during maintenance and inspection, an electrode structure that allows easy removal and attachment of the heating resistor is required.

FIG. 2 shows an example of this type of electrode structure that has been used in the past, including a supporting electrode 1 made of high-purity graphite, and a wall 2 of an airtight container connected to one end of the supporting electrode 1. It consists of a copper water-cooled electrode 3 that penetrates through and is attached thereto. The water-cooled electrode 3 is equipped with a threaded groove on the tip 4 with a slightly small diameter.
Using an insulating plate 5, insulating bushes 6, 7, insulating cylinder 8, nuts 9, 10, O-ring 11, etc.,
It is attached to the vessel wall 2 while maintaining electrical insulation and airtightness. Further, the supporting electrode 1 is formed in a cylindrical shape, and screw holes 14 and 15 are coaxially bored inward from the flat lower end surface 12 and upper end surface 13 along the axis. The supporting electrode 1 is attached by screwing its screw hole 14 onto the tip 4 of the water-cooled electrode 3. The heating resistor 16 has a mounting hole 17 and is attached to the flat upper end surface 13 of the supporting electrode 1.
The support electrode 1 is fixed to the support electrode 1 by tightening a bolt 18 placed thereon and made of high-purity graphite through the hole 17 into the screw hole 15 of the support electrode 1 . With the above configuration, electrical connection between the mechanical support of the heating resistor 16 and the water-cooled electrode 3 is obtained.

[Problem that the invention seeks to solve]

However, the conventional electrode structure as described above has the following problems. That is,
Since the bolts 18 for fastening the heating resistor 16 to the supporting electrode 1 are in direct contact with the heating resistor 16, high-purity graphite is generally used as the material of the bolts 18. However, since the bolts 18 and the supporting electrode 1 made of high-purity graphite are brittle, the bolts 18 cannot be securely fastened to the supporting electrode 1, and the supporting electrode 1 cannot be firmly fastened to the water-cooled electrode 3. Therefore, there was a risk that the mechanical support of the heating resistor 16 would become unstable, or that the electrical connection between the water-cooled electrode 3 and the heating resistor 16 would become unstable. Furthermore, since the joint between the bolt 18 and the supporting electrode 1 is exposed to high heat, the bolt 18 tends to loosen due to thermal expansion, which contributes to the instability of the mechanical support and electrical connection. . Therefore, there is a drawback that temperature control of the single crystal in the crucible becomes unstable, making it impossible to obtain the desired high quality single crystal.

[Means for solving problems]

Therefore, an object of the present invention is to provide a novel electrode device that effectively eliminates the drawbacks of the conventional electrode devices of this type described above, and is characterized by the use of mechanically strong bolts. By fastening this bolt directly to the water-cooled electrode at a location away from the heating resistor, a strong mechanical bond and good electrical connection can be achieved between the water-cooled electrode, the supporting electrode, and the heating resistor. The aim is to obtain all at once.

〔Example〕

An embodiment of the electrode device according to the present invention will be described in detail below with reference to FIG. Note that parts corresponding to those in FIG. 2 are indicated by the same reference numerals.

In FIG. 1, the supporting electrode 1 includes an inner cylindrical body 21 (first conductive member) and an outer cylindrical body 22 (second conductive member) made of high-purity graphite, which are arranged coaxially on the inside and outside. sexual parts). The inner cylindrical body 21 is a cylindrical body whose lower end is closed except for the center hole 23, and whose upper end is provided with a flange 24 for engaging with the upper surface of the heating resistor 16. Mechanically, the shaped body 22 is formed as a simple cylindrical body that functions as a spacer. The copper water-cooled electrode 3 has an upper portion 25 with a large diameter that protrudes into the container, and a portion with a smaller diameter than the upper portion 25 that extends into the container wall 2.
an intermediate portion 26 that penetrates the vessel wall 2 with a smaller diameter;
and a lower portion 27 projecting to the outside are integrally connected. and between the lower surface of the upper part 25 and the vessel wall 2, and between the outer periphery of the intermediate part 26 and the vessel wall 2.
Appropriate insulating bushes 6 and 7 are interposed between them, and a small diameter bolt 29 is inserted between the insulating block 28, which is inserted into the lower part 27 and fixed to the outer surface of the vessel wall 2, and the intermediate part 26. By screwing, the water-cooled electrode 3 is attached to the vessel wall 2 in an electrically insulated manner. 11 is an O-ring for keeping the inside of the container airtight.

The upper surface 30 of the upper part 25 of the water-cooled electrode 3 is formed flat and has a screw hole 31 in its center. , the lower end surface 33 of the outer cylindrical body 22 of the supporting electrode 1 is received.

The heating resistor 16 has an inner cylindrical body 21 at its base.
The inner cylindrical body 21 is inserted into the mounting hole 34 and placed on the upper end surface 35 of the outer cylindrical body 22. Bolt 36 inserted into cylindrical body 21
The supporting electrode 1, the water-cooling electrode 3, and the heating resistor 16 are connected by fastening the electrode to the water-cooled electrode 3 using a suitable jig. In this case, the inner diameter of the inner cylindrical body 21 is large enough to allow the head of the bolt 36 to pass through and rotate, and the hole 23 at the lower end of the inner cylindrical body 21 is formed in the peripheral wall of the inner cylindrical body 21. It is dimensioned to receive the lower surface of the bolt 36 and to allow the shank of the bolt 36 to be inserted therethrough. Further, the upper end surface 35 of the outer cylindrical body 22 receives the lower surface of the heating resistor 16, and the lower end surface 33 of the outer cylindrical body 22 is received by the step 32 on the upper surface of the water-cooled electrode 3, functioning as an intervening cylinder. and the length of the outer cylindrical body 22 is the first
As shown in the figure, the dimensions are set so that the lower end surface of the inner cylindrical body 21 does not come into contact with the upper surface 30 of the water-cooled electrode 3. Therefore, by tightening the bolts 36, the heating resistor 16 is sandwiched together with the outer cylindrical body 22 between the lower surface of the flange 24 of the inner cylindrical body 21 and the upper surface of the water-cooled electrode 3. , solid mechanical support of the heating resistor 16, and mainly the outer cylindrical body 2 between the water-cooled electrode 3 and the heating resistor 16.
A good power supply path is formed through 2.

The bolt 36 is made of molybdenum or tungsten, which is a mechanically strong high-melting point material, and enables the inner cylindrical body 21 to be firmly fastened to the water-cooled electrode 3.

〔Effect of the invention〕

The configuration of one embodiment of the electrode device according to the present invention has been clarified from the above explanation, and according to such a configuration, the connection between the supporting electrode 1, the water-cooled electrode 3, and the heating resistor 16 can be maintained by cooling. This can be done by tightening the bolts 36 in the vicinity of the water-cooled electrode 3 and away from the heating resistor 16, so there is no loosening of the bolts due to heat, and the mechanically strong high Since the bolts 36 made of molybdenum or tungsten, which are melting point materials, can be firmly fastened, strong mechanical support of the heating resistor 16 and the connection between the water-cooled electrode 3 and the heating resistor 16 can be achieved.
A good and stable electrical connection can be obtained all at once. In addition, since the heating resistor 16 can be attached and detached by simply attaching and detaching the bolts 36, the heating resistor 16 can be easily attached and detached.
Furthermore, there are many advantages such as being able to accurately position the heating resistor 16 within the closed container.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the electrode device of the present invention, and FIG. 2 is a sectional view showing a conventional electrode device. In the drawings, 1 is a supporting electrode, 2 is a vessel wall, and 3 is a supporting electrode.
is a water-cooled electrode, 16 is a heating resistor, 21 is an inner cylindrical body, 22 is an outer cylindrical body, 28 is an insulating block,
36 indicates bolts, respectively.

Claims (1)

[Scope of Claims] 1. A water-cooled electrode that penetrates a tube wall of a container and is attached thereto, and a base end connected to the water-cooled electrode within the container, and a heating resistor that is removably attached at a distal end. In an electrode structure including a supporting electrode, the supporting electrode includes a first electrically conductive member having a means at one end that engages with a first surface of the heating resistor; a second conductive member interposed between a second surface of the body opposite to the first surface and the water-cooled electrode, and the first conductive member is connected to a bolt at the other end. By being fastened to the water-cooled electrode with . An electrode structure for a heating resistor, characterized in that a base end portion of the supporting electrode is configured to be connected to the water-cooled electrode. 2. The first conductive member of the supporting electrode is
a lower end portion having an inner diameter that allows the head of the bolt to be inserted and rotated; a lower end portion that receives the lower surface of the bolt head and has a hole through which the shank of the bolt is inserted; and the first surface of the heating resistor. an inner cylindrical body having an upper end having a flange forming means for engaging the second electrically conductive member, the second electrically conductive member being disposed outside and coaxially with the first electrically conductive member; and the second of the heating resistor.
Claim 1 comprising an outer cylindrical body interposed as a spacer between the surface of the water-cooled electrode and the upper surface of the water-cooled electrode.
Electrode structure described in section. 3. The electrode structure according to claim 1, wherein the first and second conductive members are made of graphite. 4. The electrode structure according to claim 1, wherein the bolt is made of a high melting point material. 5. The electrode structure according to claim 4, wherein the high melting point material is made of molybdenum. 6. The electrode structure according to claim 4, wherein the high melting point material is tungsten.