JPS6335600B2 - - Google Patents

Description

[Detailed description of the invention]

[Background and Objectives of the Invention] The present invention relates to a method for producing a compound semiconductor, and more particularly to a method for producing a single crystal of a compound semiconductor by pulling and growing a single crystal of a compound semiconductor from a melt synthesized by contacting a non-volatile component melt with volatile component vapor. It is something. [Conventional technology] Conventionally, gallium phosphide (GaP), indium phosphide (InP), gallium arsenide (GaAs), etc.
A method for manufacturing compound semiconductors containing non-volatile components and volatile components of group compound semiconductors is to melt these separately manufactured polycrystals in a crucible and pull up single crystals from this melt. The Kralski method has become mainstream. Unlike this pulling method using polycrystals, a method has been proposed in which a melt of a non-volatile component is reacted with vapor of a volatile component to produce a melt of the target compound, and a single crystal is pulled directly from this melt. There is. For example, a cold room container containing volatile components is provided below a crucible containing a melt of nonvolatile components covered with an inert liquid, and a porous material such as boron nitride (BN) is placed between the crucible and the cold room container. A partition wall made of a material with pores or a material with pores is provided, and the volatile component vapor is supplied through the partition wall to the non-volatile component melt while controlling the vapor pressure by heating the cold room container and reacting with the non-volatile component melt. It has been proposed to pull a single crystal from a liquid (Special Publication No. 12152/1983). However, even under a high-pressure inert gas atmosphere, if the vapor pressure of the volatile component vapor is controlled to be stoichiometrically equivalent and then supplied to the nonvolatile component melt, the vapor pressure of the volatile component will be high. Therefore, a considerable amount of unreacted volatile components evaporate during the reaction. In addition, due to the reaction near the melting point of the crystal, due to the reaction with an inert liquid component such as B ₂ O ₃ as a melt coating material,
This increases the amount of impurities such as boron. Therefore, in order to suppress the loss of volatile components and the contamination of impurities, when the temperature is lower than the melting point of the crystal and the vapor pressure of the volatile component vapor is lower than the stoichiometrically equivalent vapor pressure, For example, in the case of InP, since the specific gravity of InP is smaller than that of In melt,
The InP melt tries to float above the melt, but the InP melt is formed at the P vapor outlet, which delays the further progress of the reaction, so it takes time for the reaction to proceed uniformly to the inside of the crucible. There's a problem. [Object of the Invention] The present invention has been made in view of the above-mentioned prior art, and its purpose is to improve the reaction between non-volatile components and volatile components without allowing volatile component vapor to escape outside the reaction system. It is an object of the present invention to provide a method for manufacturing a compound semiconductor, which can be performed smoothly and with less contamination of impurities, and can grow high-quality crystals. [Summary of the Invention] That is, the gist of the present invention is that, as a first step, the temperature inside the crucible is lowered to below the melting point of the compound semiconductor, and the temperature of the volatile component storage container is controlled to stoichiometrically control the volatile component vapor. After reacting with the nonvolatile component melt at a vapor pressure lower than the equivalent vapor pressure, and performing the reaction at this low vapor pressure, the temperature in the crucible is raised to around the melting point of the compound semiconductor as a second step. The temperature of the volatile component storage container is raised to cause the volatile component vapor to react with the unreacted non-volatile component melt at a vapor pressure that is stoichiometrically equivalent. After the reaction is completed, a single crystal of the compound semiconductor is manufactured by a pulling method. [Example] The present invention will be described in detail below using the example shown in FIGS. 1 and 2. FIG. 1 is a schematic diagram showing an example of a manufacturing apparatus for implementing the present invention. In Figure 1,
Reference numeral 1 denotes a reaction vessel having a heat-resistant, pressure-resistant, and airtight structure.The side wall of the reaction vessel 1 is provided with a gas inlet 2 for inert gas such as nitrogen or argon, and a gas outlet 3. A crystal pulling rod 4 is mounted so as to be vertically movable. Inside the reaction vessel 1, a crucible 5 made of graphite and a volatile component storage container 6 are installed.
A steam introduction pipe 7 is detachably attached to the volatile component storage container 6, and the steam introduction pipe 7 extends to the bottom of the crucible 5 as shown in the figure, and a steam discharge port 8 at the tip of the steam introduction pipe 7 As shown in FIGS. 2a or 2b, the pores 8a have tapered tips, or a filter plate 8b is attached. 9 is a heating furnace for the crucible 5, and 10 is a heating furnace for the nonvolatile component storage container 6. 11 is a non-volatile component melt in the crucible 5; 12 is a compound semiconductor melt; 13 is a compound semiconductor melt;
indicates a liquid sealing material, and 14 is a volatile component contained in the volatile component storage container 6. The reason why the steam introduction tube 7 is made detachable is to enable it to be removed each time crystal growth occurs. This was done in order to facilitate the adjustment of the steam discharge pressure and to increase the
This is to prevent backflow of the compound semiconductor melt 12 and the compound semiconductor melt 12.

【table】

[Table] Next, an example of a specific manufacturing method will be described using the case of growing an InP single crystal as an example. The pressure-temperature-composition relationship of InP is shown in Table 1, which indicates that, for example, indium (In)
Assuming that the temperature is 1057°C and phosphorus (P) is 585°, the composition of the InP melt is 1:1 in terms of chemical equivalence, and the pressure at this time is 40 atmospheres. As a growth method, a non-volatile component (In) 11 and a sealing material (B ₂ O ₃ ) 13 are placed in a crucible 5, and an excess of the volatile component (P) 14 is placed in a volatile component storage container 6. put in. Then, when the temperature of the crucible 5 is raised by the heating furnace 9, In1 reaches 156℃.
1 becomes a melt and flows to the bottom of the crucible 5. When the temperature further increases to 460℃, B ₂ O ₃ 13 melts,
Cover In11. Then, the temperature of the crucible 5 is raised to about 1000°C. At the same time, the volatile component storage container 6 is heated by the heating furnace 10, while maintaining the pressure balance.
Raise the temperature to 420℃. Under these conditions, the vapor pressure of P is 1.1 atm, which is stoichiometrically lower than the equivalent amount, as shown in Table 1, and the P vapor passes through the steam inlet pipe 7 and the steam outlet 8, and the P vapor passes through the steam inlet pipe 7 and the steam outlet 8. Mixed into the melt 11, an InP compound semiconductor melt 12 with a P composition of about 34% (specific gravity of about 5.6) is formed, and the InP compound semiconductor melt 12 has a specific gravity of about 7.3.
It is liberated in a layer between 2.5 and 13 B ₂ O ₃ . In this way, by reacting with the In melt at a temperature lower than the melting point of the crystal and at a P vapor pressure lower than the stoichiometrically equivalent amount, the InP compound semiconductor melt 12
may be liberated between In11 and _B2O313 in _a layered manner, so P vapor does not escape through _B2O313 , and contamination of _impurities from _B2O313 is suppressed _. be able to. When the reaction of In11 in the crucible 5 is almost completed, inert gas is introduced from the gas inlet 2, and while maintaining pressure balance, the crucible 5 is heated to the melting point of InP, 1057.
The temperature of the volatile component storage container 6 is raised to 585°C to bring the vapor pressure of P to 40 atmospheres, which is the stoichiometric equivalent, and the mixture is left for a while until the entire reaction becomes uniform. Once the InP compound semiconductor melt 12 with stable stoichiometric properties is produced, the single crystal pulling rod 4 is gradually lowered to perform seeding and pull and grow the InP compound semiconductor single crystal. In this way, a compound semiconductor is manufactured. According to the embodiment of the present invention described above, since In and P are first reacted directly at the gas phase-liquid layer interface at a relatively low temperature and low vapor pressure, P is removed from the reaction system. There is almost no escape from
In addition, the boron impurity concentration can be reduced to 1/10 of the conventional method, resulting in high quality crystals. Furthermore, although the synthesis reaction rate is initially a little slow due to the compound semiconductor melt such as InP generated by the reaction, the reaction speeds up by increasing the P vapor pressure, and the synthesis reaction proceeds extremely smoothly, making it suitable for mass production. It is. [Effects of the Invention] As explained above, according to the present invention, the reaction between the non-volatile components and the volatile components can be carried out favorably and smoothly without escaping the volatile component vapor to the outside of the reaction system. In addition, there is an effect that high-quality crystals can be grown with less contamination of impurities.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a manufacturing apparatus for carrying out the compound semiconductor manufacturing method of the present invention, and FIG. 2 is a structure showing an example of the steam outlet of the steam introduction pipe in FIG. 1. It is an explanatory diagram. 1: Reaction container, 2: Gas inlet, 3: Gas outlet, 4: Single crystal pulling rod, 5: Crucible, 6: Volatile component storage container, 7: Steam inlet pipe, 8: Steam outlet, 9, 10: heating furnace, 11: non-volatile component melt, 12: compound semiconductor melt, 13: sealing material,
14: Volatile component.

Claims (1)

[Claims] 1. A non-volatile component melt and a liquid sealant are stored in a crucible, and a volatile component storage container storing volatile components is provided outside the crucible, and connected to the volatile component storage container. Insert the tip of the vapor introduction tube to the bottom of the nonvolatile component melt, supply volatile component vapor from the tip of the vapor introduction tube to cause a synthesis reaction, and form a compound semiconductor from the melt obtained by the synthesis reaction. In the method for manufacturing, as a first step, the temperature inside the crucible is made equal to or lower than the melting point of the compound semiconductor, and the temperature of the volatile component storage container is controlled so that the volatile component vapor becomes stoichiometrically equivalent. After performing the reaction at this low vapor pressure, the temperature inside the crucible is raised to around the melting point of the compound semiconductor as a second step, The temperature of the volatile component storage container is raised to cause the volatile component vapor to react with the unreacted non-volatile component melt at a stoichiometrically equivalent vapor pressure, and the reaction is completed. A method for manufacturing a compound semiconductor, comprising: manufacturing a single crystal of the compound semiconductor by a pulling method. 2. The method for manufacturing a compound semiconductor according to claim 1, wherein the compound semiconductor containing a volatile component is indium phosphide, gallium arsenide, or a gallium phosphide compound semiconductor.