JPS62162688A - Production of compound semiconductor crystal - Google Patents

Abstract

PURPOSE:To produce a compound semiconductor crystal without any inclusion in good yield at a high growth rate, by placing a coil surface of a high-frequency oscillating coil for high-frequency induction heating obliquely to the crystal growth direction of a raw material melt. CONSTITUTION:Composition elements are contained in a graphite boat 11 inserted into a quartz reaction tube 10 placed in a pressure vessel and the quartz reaction tube 10 is slowly moved in the direction of arrow (C) while preparing a raw material melt 2 melted by a high-frequency oscillating coil 5 while heating to prepare a compound semiconductor crystal. The coil surface (B-B) of the high-frequency oscillating coil 5 is tilted about 30 deg. at the crystal growth direction. Thereby a crystal melt interface appears obliquely to the top or bottom surface of the boat 11. Since the composition elements shifting to a larger side than the stoichiometry and extruded in the crystal growth are extruded to the top or bottom surface of the crystal, the shifted composition elements are not incorporated into the interior of the crystal. As a result, the aimed compound semiconductor without any inclusion can be prepared in good yield at a high growth rate.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a compound semiconductor, particularly a 1-VA compound semiconductor, by a boat growth method using high-frequency induction heating.

<Prior Art> A known method for producing a compound semiconductor crystal is to produce it from the constituent elements constituting the compound semiconductor by a so-called boat growth method such as a horizontal Bridgman method or a zone melting method.

Among the methods for producing compound semiconductor crystals using this boat growth method, the method in which the constituent elements of the compound semiconductor are melted by high-frequency induction heating has the advantage of being able to quickly produce large amounts of the desired compound semiconductor crystals. It is superior to the heating method of

High-frequency induction application #41 is excited by the change in magnetic field caused by high-frequency application 1ζ.It actively utilizes the ohmic loss caused by the induced current and heats the conductor placed in the alternating magnetic field, that is, the object to be heated, to the desired temperature. It is something that gets you a rise.

A typical example of semiconductor crystal growth using high-frequency induction heating is the high-pressure zone melting method (hereinafter referred to as r
HPZM method) will be explained.

In this HPZM method, as shown in FIG. 2, indium (In) 4 is placed in a graphite bowl 1-3 inserted into the center of a quartz reaction tube 2 inside a pressure vessel 1, and is heated and melted by a high-frequency transmitter coil 5. , the melting point of the raw material (1! (1nP)) is maintained at a temperature higher than the melting point of the raw material.
I
Prepare nP melt.

The inside of the pressure vessel 1 is normally maintained at a pressure of about 10 to 50 atmospheres to prevent rupture due to an increase in internal pressure due to vaporization of the inside P of the quartz reaction tube 2.

In this state, the quartz reaction tube 2 is gradually moved in the direction of arrow C, and [nPi! l! I by solidifying the liquid
An nP crystal is obtained.

However, in the production of InP crystals by this HPZM method, conventionally, when high-frequency induction heating is performed, the coil plane B--B of the high-frequency transmitting coil 5 has been arranged in a direction perpendicular to the crystal growth direction C, as shown in FIG. When a current is passed through the high frequency coil in such a state, the heat generating portion of the graphite bow 1-11, which is the object to be heated, becomes 13 in FIG. Under such conditions, the graphite boat 11 is moved to grow crystals, but the solidification heat accompanying the growth escapes from the boat 11, so the raw material melt solidifies from the outer periphery of the reaction vessel and the crystals grow. grow up. When the moving speed of the graphite boat 11 is increased, the crystal melt interface becomes extremely convex with respect to the crystal growth direction, as shown in FIG. 314. Therefore, this type of crystal growth method uses stoichiome in the melt state!
・Since it is impossible to make ri (5toichioa+etry) completely equal, during crystal growth, melt state tenostoichiometry (Stoichio@etr
y) The compositional elements that are shifted to the larger side should be pushed out to the tip of the raw material melt by the amount of the shift.

As shown in FIG. 3, when the crystal-melt interface 14 becomes extremely convex, the concentration of the shifted compositional elements increases in the convex portion 15.
InP was incorporated into the crystal, resulting in a poor yield of the resulting InP crystal, and it was not possible to increase the growth rate.

On the other hand, in the specification of Japanese Patent Publication No. 57-27075, a heel crystal and silicon as a dopant are placed in a quartz boat together with gallium, and arsenic is By placing the quartz container vacuum-sealed in a transparent quartz container into a heating furnace consisting of a high-temperature furnace section and a low-temperature furnace section that have heat dissipation holes and have a structure in which temperature distribution differs in the vertical direction,
This shows that the interface between the solid and liquid of the raw material melt during crystal growth can be tilted with respect to the growth direction, and the impurity concentration on the inner surface of a 100-sided wafer can be made uniform.

<Problems to be Solved by the Invention> However, since the method for manufacturing compound semiconductor single crystals disclosed in the specification of Japanese Patent Publication No. 57-27075 follows a resistance heating method, the temperature at the growth interface is It is difficult to increase the gradient, that is, the temperature gradient between the high temperature furnace and the low temperature furnace.

This becomes more difficult especially in high temperature environments such as the I-I P Z M method.

Therefore, when the crystal melt solidifies, the stoichiometry
In order to prevent compositional elements that deviate from the crystal from being incorporated into the crystal, the growth rate must be kept sufficiently low, making mass production difficult.

On the other hand, the high-frequency induction heating method has the advantage of being able to increase the temperature gradient during solidification because it can heat locally, but as shown in the specification of Japanese Patent Publication No. 57-27075, Since it is not possible to use a heating method that divides the heating method into a low-temperature section and a low-temperature section, it has not been possible to tilt the raw material melt interface in the crystal growth direction.

The present invention aims to eliminate the drawbacks of the conventional compound semiconductor crystal manufacturing methods described above, improve the yield of compound semiconductor crystal manufacturing, and provide a compound semiconductor crystal manufacturing method that has a high growth rate.

Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention arranges the constituent elements of a compound semiconductor crystal to be manufactured on a boat, and then heats these constituent elements by high frequency induction to generate the crystal. When manufacturing a compound semiconductor crystal by crystal-growing the raw material melt, the coil surface of the high-frequency transmission coil for high-frequency induction heating is arranged so as to be inclined to the crystal growth direction of the raw material melt, and the crystal melt interface is It is characterized in that the growth is grown tilted toward the top or bottom surface.

Due to the above structure, the heat-generating parts on the boat appear in the parts that are tilted with respect to the top and bottom of the boat.
Even if the crystal growth rate of the raw material melt is increased, the crystal melt interface will appear inclined with respect to the top or bottom surface of the boat.

Therefore, the compositional elements which are largely deviated from the stoichiometry that are pushed out during crystal growth are pushed out to the upper or lower surface of the crystal, so that these deviated compositional elements are not taken into the crystal.

Example of implementation Next, one embodiment of the present invention will be described.

FIG. 1 shows the configuration of the main parts of a manufacturing apparatus using the HPZM method used to carry out the method for manufacturing compound semiconductor crystals of the present invention. While creating a raw material melt 12 by heating and melting a graphite boat 11 containing constituent elements placed in a quartz reaction tube 10 with a high-frequency coil 5, move the quartz reaction tube 10 in the direction of arrow C.
The target compound semiconductor crystal is produced by gradually moving in a direction. However, the coil plane B-B of the high-frequency transmitting coil 5 in Fig. 1 is approximately 30° with respect to the crystal growth direction.
The appropriate angle of inclination is to keep it tilted.

With this equipment, InP was grown at a crystal growth rate of 60 ma/h.
When we prepared In inclusion (1ncl
It was possible to produce a high-quality InP polycrystalline body free from oxidation. Moreover, the yield reached 90%, confirming an extremely high yield.

On the other hand, as shown in FIG. 3, the coil plane B-B of the high-frequency transmitting coil 5 was arranged to be perpendicular to the crystal growth direction (cl) using the same apparatus as the apparatus of the previous example.
When the crystal was produced, a crystal with a total length of 300 m was obtained at a crystal growth rate of 60 m/h, but the first half was 150 m long.
Inclusions were observed from the center to the bottom of the ingot, and the yield was only 60%. In order to eliminate In inclusions, the crystal growth rate had to be reduced to 20 mm/h.

More than 1 ton of fruit! Although InP has been explained as an example and a comparative example, other
-■ Group compound semiconductor crystals can also be produced in a similar manner. Furthermore, the compound semiconductor crystal obtained by this method can be produced not only as a polycrystal but also as a single crystal, and is particularly suitable for a method for producing a polycrystalline compound semiconductor.

<Effects of the Invention> As is clear from the above description, when compound semiconductor crystals are manufactured by the boat growth method using high-frequency induction heating, according to the present invention, the high-frequency transmitting coil surface is tilted with respect to the crystal growth direction of the raw material melt. By arranging them in this way, it is possible to manufacture compound semiconductor crystals with good yield and without inclusions. Moreover, it is possible to accelerate the growth rate.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the main parts of a high-pressure zone melting compound semiconductor crystal manufacturing apparatus used to carry out the compound semiconductor crystal manufacturing method of the present invention, and FIG. 2 is a schematic diagram of a conventional high-pressure zone melting compound semiconductor crystal manufacturing apparatus. FIG. 3 is a block diagram of a main part of a conventional high-pressure shimmelting compound semiconductor crystal manufacturing apparatus using high-frequency induction heating. In the drawing, 1-Pressure vessel, 2.10. Quartz reaction tube, 3.11.. Boat, 5. High-frequency transmitting coil, 12. Raw material melt, 14. Crystal melt interface, B-B. High-frequency transmitting coil. Coil surface, C. Crystal growth direction. Patent application agent Sumitomo Electric Industries Co., Ltd.

Claims (1)

[Claims] After placing the constituent elements of the compound semiconductor crystal to be manufactured on a boat, high-frequency induction heating is used to produce the compound semiconductor crystal by crystal-growing the raw material melt produced by high-frequency induction heating of these constituent elements. A method for producing a compound semiconductor crystal, characterized in that the coil surface of a high-frequency transmitting coil for use is arranged to be inclined with respect to the crystal growth direction of a raw material melt, and the crystal melt interface is grown with the crystal melt interface inclined toward the upper or lower surface of a boat.