JPS6051692A - Growing apparatus of single crystal semiconductor - Google Patents

Abstract

PURPOSE:To provide a titled apparatus free from fear of a magnetic field leakage and with small consumption of energy by winding a coil at a position symmetrical to the center of a magnetic crucible in a chamber, and constituting the chamber proper capable of being cooled. CONSTITUTION:In titled apparatus, a seed crystal 20 which is hung freely rotatably by a chain 19 is immersed in a molten semiconductor material 24 in a crucible 16 which is supported freely rotatably by a supporting rod 14 in a chamber 11, and pulled up slowly to grow a single crystal 25. Said chamber 11 is formed of a nonmagnetic body 12 equipped with a cooling waterway 21 and a magnetic body 13 surrounding the outside thereof. In addition a couple of coils 211 and 212 generating respectively a pole having a different polarity and/or the other couple of coils 231 and 232 are wound at a position symmetrical to the center of the crucible 16 in said magnetic body 13. A magnetic field is then impressed to the molten semiconductor material 24 to restrain the heat convection. An unfavorable influence is not exerted upon various kinds of sensors for controlling in this way, and a high-quality single crystal semiconductor can be obtained with small consumption of energy.

Description

[Detailed description of the invention] [Technical field of invention] This article 9G relates to improvements in single crystal semiconductor growth equipment.

[Technical background of the invention and its problems]

Single crystal semiconductors used for manufacturing semiconductor devices are mainly manufactured by the Czochralski method (CZ method). For example, when manufacturing single crystal silicon, this method
It is as follows. In other words, a quartz crucible is rotatably supported in a chamber, a silicon raw material is put into this quartz crucible, it is melted by a heater placed around the quartz crucible, and the molten silicon is suspended from above the crucible so as to be rotatable. Single-crystal silicon is grown by dipping the seed crystal and pulling it up.

By the way, in this method, during the growth of single crystal silicon, forced convection and thermal convection occur in the molten silicon due to rotation, so the impurity concentration unevenness (striation) in the grown single crystal silicon becomes significant. There is a drawback that it becomes difficult to freely control the concentration.

Therefore, a technique is known in which a magnetic field is applied to the molten semiconductor raw material during the growth of a single crystal semiconductor (for example,
104791, JP-A-56-104795, JP-A-56
-121339, JP-A-57-149894, etc.).

The schematic structure of these conventional single crystal semiconductor growth apparatuses is as shown in FIG. 1 or 2.

That is, in the apparatus shown in FIG. 1, a crucible 2 is rotatably supported in a chamber 1, and two normal conducting magnets are placed outside the chamber 1 at positions corresponding to both sides of the crucible 2.
J11J2 are arranged so that the poles having different polarities face each other. In this device, a seed crystal 5 is immersed in the molten semiconductor raw material 4 while applying horizontal tap water (indicated by a broken line in the figure) to the M-strand conductor raw material 4 in the root 2 by a normal conducting magnet 31r32. By pulling it up, a single crystal half body 6 is grown.

The device shown in FIG. 2 is the same as the device shown in FIG.
In place of the normal conductive magnet 31132 in the cage, a ring-shaped normal conductive or superconducting magnet 7 is arranged around the outer periphery of the Y member 1. In this device, is the normal conducting or superconducting magnet 7 used? While applying a vertical magnetic field (indicated by a broken line in the figure) to the molten semiconductor raw material 4 in the molten semiconductor raw material 2, a seed crystal is immersed in the molten semiconductor raw material 4 and pulled up, thereby growing a single crystal semicircular body 6. be done.

These devices can suppress convection within the molten semiconductor raw material 4, thereby reducing the occurrence of striations in the grown single crystal semiconductor, and making it easier to control the level of impurity concentration. There is.

However, conventional devices have the following shortcomings.

(1) In the apparatus shown in FIG. 1, two normal conducting magnets are arranged on the left and right sides of the chamber, so the entire apparatus becomes extremely large. In addition, the cooling system for the chamber and the magnet are separate systems, which increases energy consumption. Also,
In the device shown in Figure 2, when a superconducting magnet is used and the refrigerant for cooling the magnet is a closed circuit, the energy consumption is small, but when a normal conducting magnet is used, the energy consumption is small compared to the device shown in Figure 1. Similarly, energy consumption is high.

(11) Various sensors for executing computer control are installed in the breeding device. However, in both the apparatuses shown in FIGS. 1 and 2, the magnetic field acts at a location far away from the molten semiconductor raw material, so such leakage magnetic fields can cause sensor malfunctions and distort the image of the TV screen. For example, diameter control may become impossible. Therefore, there is a drawback that the sensor must be installed at a farther position or a shield must be provided for each sensor.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and is a single crystal semiconductor capable of realizing high quality single crystal semiconductors with less energy consumption and without affecting the various sensors used for control. This is intended to provide a semiconductor growth apparatus 5f.

[Summary of the invention]

The single-crystal semiconductor growth device of the present invention has a chamber made of a non-magnetic material and a magnetic material surrounding the outside thereof, and the roots of the magnetic material are located at vertically symmetrical positions with respect to the center. Applying a magnetic field to the molten semiconductor raw material by winding at least one pair of coils around the inner surface of the magnetic material so as to generate different poles, and flowing a coolant within the non-magnetic material or between the non-magnetic material and the magnetic material. It is characterized by:

According to such a device, since the chamber itself serves as a yoke, there is no fear of magnetic field leakage and no adverse effects on various control sensors. In addition, by flowing a refrigerant inside the non-magnetic body or between the non-magnetic body and the amphoteric body, the entire chamber can be cooled, and the temperature rise caused by the heater and coil can be prevented at the same time, reducing energy consumption. Less is.

[Embodiment J of the Invention Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

Reference numeral 11 in FIG. 3 is a chamber consisting of a non-magnetic stainless steel 12 with an inner diameter of 610 mm and a magnetic stainless steel 13 surrounding the outside with a thickness of 15 fins or more, with an open top and bottom.

A support rod 4 is rotatably inserted into the lower opening of the chamber 11 to support the graphite protector 15, and the protector 15 has an internal diameter of 12 inches (304,8 scale).
The quartz crucible 16 is protected. A heater 17 and a heat insulating tube 18 are disposed on the outer periphery of the insulating body 5. Further, a chain 19 is suspended from the upper opening of the chamber 11, and holds a seed crystal 20.

Further, a cooling water passage 2 is provided inside the non-magnetic stainless steel 12 constituting the chamber 11, so that cooling water flows therethrough. 1 more chamber 11
On the upper and lower inner surfaces of the magnetic stainless steel 13 constituting the crucible 16, two pairs of coils 221 g 222 r are installed in the winding grooves so that poles of different polarity are generated at positions that are approximately vertically symmetrical with respect to the center of the crucible 16. 231 + 2 J
″2 are wound.These coils 221 + 22
x +231.23. A direct current of 20 A or more can be applied to the tube.

Growth of a single crystal semiconductor using the above apparatus is performed as follows. First, a silicon raw material, for example, is placed in the crucible 16 and melted by the heater 17 in an atmosphere of, for example, argon gas. As shown in FIG. 4, coils 221, 22. and coils 231 and 232 (shown by broken lines in the figure, the combined magnetic field acts almost vertically) is applied to the non-magnetic stainless steel 1.
2. Pour cooling water into the tank. In this state, molten silicon 2
Seed crystal 20f in 4: soaked, crucible 16 and seed crystal 20 and 1
Single crystal silicon 25 is grown by pulling up seed crystal 20 while rotating in one direction.

According to the above device, the coil 221 r is attached to the magnetic stainless steel 13 constituting the chamber I.
22*1231 + 232 is wound, and the magnetic stainless steel spool 13 itself becomes a yoke, and the inside thereof can be used as a closed circuit for the magnetic field, so that the magnetic field does not leak to the outside. Therefore, there is no adverse influence of various sensors for control, and for example, diameter control can be performed satisfactorily. Further, since cooling water is flowing inside the non-magnetic stainless steel 12 that constitutes the chamber 11, the entire chamber 11 can be cooled. Therefore, the temperature rise due to the heater 17 and the coil J 21 y
222 r 2JJ 1232 can be prevented at the same time, resulting in less energy consumption.

Furthermore, by applying a magnetic field, convection in the molten silicon 24 can be suppressed and the quality of the single crystal silicon 25 can be improved.

In fact, using the above device, 20 kg of high-purity silicon raw material was charged into the crucible 16, and the coil 221 H222r 23 was grown using the normal dislocation-free single crystal growth method using the dash method.
Single crystal silicon was grown with a diameter of 103±1 sieve, specific resistivity of 1 to 3 Ω・F, N-type, and crystal orientation (100) while applying a magnetic field of 30o Gauss according to s + 23 * , the results shown in Table 1 below were obtained.

In addition, the reference examples in Table 1 below are normal C without applying a magnetic field.
This is based on the Z method.

From Table 1 above, it can be seen that the specific resistivity fluctuates and the minute specific resistivity distribution lasts for several seconds.

Further, when comparing the device dimensions, leakage magnetic field, and cooling cost with the conventional device (comparative example) shown in FIG. 1, the results shown in Table 2 below were obtained.

Table 2 From Table 2 above, the single crystal semiconductor growth device of the present invention has compact device dimensions compared to conventional devices, and leakage 1
It can be seen that it is much better in terms of field and cooling costs.

In the above embodiment, two pairs of coils are wound on the upper and lower inner surfaces of the magnetic stainless steel that constitutes the chamber, but the present invention is not limited to this, and as shown in FIG.
21, 22. Alternatively, a diagonal magnetic field may be applied to the bath-molten silicon 24 using only a magnetic field.

In the above example, the cooling water was poured into the non-magnetic stainless steel that makes up the chamber, but the cooling water is not limited to this, and the cooling water can be flowed between the non-magnetic stainless steel and the magnetic stainless steel. Good too. Additionally, in addition to these, cooling water may also be allowed to flow inside the magnetic stainless steel to mainly prevent temperature rise due to the coil.

Furthermore, although the above description has been made regarding the case of growing single crystal silicon, it goes without saying that the apparatus of the present invention can also be used to grow other single crystal semiconductors such as GaAs.

〔Effect of the invention〕

As described in detail above, the single crystal semiconductor growth apparatus of the present invention does not require a shadow tube to touch each sensor for control.
This method has remarkable effects such as being able to produce high quality single crystal semiconductors with low energy consumption.

[Brief explanation of the drawing]

1 and 2 are schematic configuration diagrams of a conventional single crystal semiconductor growth apparatus, respectively, FIG. 3 is a sectional view of a single crystal semiconductor growth apparatus according to an embodiment of the present invention, and FIG. 4 is a schematic diagram of a conventional single crystal semiconductor growth apparatus. FIG. 5, which is an explanatory diagram showing the state of the Fli field, is a sectional view of a single crystal semiconductor growth apparatus in another embodiment of the present invention. 11... Chamber, 12... Non-magnetic stainless steel, 13... Magnetic stainless steel, 14
...Supporting rod, 15...Protection body, 16...Rutsu cod?
, 17... Heater, 18... Heat insulation cylinder, 19... Chain, 20... Seed crystal, 2... Cooling water flow path, 2
21 +22z r231 + 2 Jz...Coil, 24...Bath melt silicone, 25...Single bond 4-layer silicone. Applicant's representative Patent attorney Takehiko Suzue Figure 3 @ Figure 4 Figure 5

Claims (1)

[Claims] A single crystal semiconductor is grown by rotatably supporting a crucible in a chamber, dipping a seed crystal rotatably suspended from above the crucible into the molten semiconductor raw material in the crucible, and pulling up the seed crystal. In the apparatus, the chamber is formed of a non-magnetic material and a magnetic material surrounding the outside thereof, and the magnetic material is arranged such that poles of different polarity are generated at positions that are approximately vertically symmetrical with respect to the center of the crucible of the magnetic material. Single-crystal semiconductor growth characterized by applying a magnetic field to the molten semiconductor raw material by winding at least a pair of coils around the inner surface 1, and flowing a coolant in the non-magnetic body 1 or between the non-magnetic material and the magnetic material. Device.