JPH0597594A - Synthesis of group iii-v compound semiconductor composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition (crystal) economically and safely by suppressing the deformation of an ampule due to the rapid As gas shortage in a boat during the synthesis. CONSTITUTION:Arbenic 2 as a raw material for the final GaAs composition and Ga 1 in a quartz boat 3 are put into a quartz ampule 5. The Ga 1 is incorporated, in advance, with a specified proportion of GaAs polycrystal. Its amount is such as to be 5-95wt.% of the amount off a GaAs melt to be produced. In case of <5wt.%, the synthetic reaction will proceed vigorously; for >95%, the final GaAs crystal of stoichiometric composition can hardly be obtained, or the synthetic reaction will hardly proceed, leading to time consuming. In this way, preaddition of a specified amount of the GaAs polycrystal to the Ga 1 in the boat 3 does not cause the synthetic reaction rapidly, suppressing the deformation of the ampule 5 due to the rapid As gas shortage in the boat 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Ga by the horizontal boat method.
The present invention relates to a method for synthesizing a III-V group compound semiconductor composition such as As, and more particularly, to a method in which destruction of a closed container due to a synthesis reaction is prevented.

[0002]

2. Description of the Related Art III-V compound semiconductor crystals, especially Ga
As is an industrially important semiconductor material and is widely used for applications such as a light emitting element, a high frequency element, and an integrated circuit element. The most common method of manufacturing the so-called horizontal boat method. This is GaA housed in a boat
A single crystal is grown by solidifying the melt from one end. During growth, GaAs melt (melting point 1238
Dissociation of As from (.degree. C.) occurs. Therefore, it is necessary to prevent the volatilization thereof, and normally, As is contained in an ampoule constituting a closed container, and dissociation is prevented by the partial pressure of vaporized As gas.

In order to obtain a GaAs melt by the horizontal boat method, the following two methods have been widely used.

(1) A method in which a polycrystal synthesized by the boat method and other methods (vertical crystal growth method, etc.) is housed in a boat as a raw material and melted.

(2) A method in which GaAs is synthesized in the boat by reacting the raw material Ga housed in the boat with the sublimated and gasified raw material As to form a melt.

Since the method of (1) includes the case of synthesizing by the method of (2), basically GaAs is often synthesized by the method of (2). Therefore, here, an example of a crystal manufacturing apparatus for growing a single crystal by the method (2) is schematically shown in FIG.

The ampoule 5 is heated by heaters 6 and 7. The GaAs synthesis part at one end of the ampoule 5 is heated by the high temperature heater 6 which gives the melt holding temperature,
The s supply section is heated by a low temperature heater 7 which gives a vapor pressure temperature. The raw material Ga1 is stored in the boat 3 in the GaAs synthesis section, and the raw material As2 is stored in the As supply section. Then, the Ga stored in the boat 3 is changed to GaAs by the high temperature heater 6.
Heat to the melting point of. Then, the temperature of the raw material As2 is raised by the low-temperature heater 7 and controlled at a sublimation point of around 610 ° C. to cause gasification of As, and As gas transported through the diffusion barrier 4 and Ga in the boat GaAs is synthesized by the reaction of.

Among the members used in this apparatus, quartz glass is the most widely used as a boat material. In addition, BN or AlN which is inactive with GaAs, or SiC or Si ₃ N ₄ which can withstand high temperature may be used as a growth member. The ampoule must contain As gas as described above, and quartz is usually used. The diffusion barrier 4 is also made of quartz.

[0009]

By the way, in the GaAs synthesis method by the lateral boat method described above, it is necessary to reduce the pressure difference between the inside and outside of the ampoule. This is because the quartz ampoule does not withstand a large pressure and thus easily breaks when the pressure difference is large, and at the high temperature near the melting point of GaAs, it easily softens and easily breaks from deformation. As a device for that purpose, a method of controlling the temperature of the As supply unit is generally performed. That is, the pressure of As sublimated at 610 ° C. is almost 1
It is equal to the atmospheric pressure, and by controlling this, the destruction of the ampoule 5 is prevented.

However, in the synthetic reaction, the reaction proceeds all at once, so the As partial pressure is momentarily lowered and the ampoule is often deformed and destroyed. In order to prevent this, it is necessary to raise the temperature of the As supply section to rapidly increase the supply of As.
I can't really catch up. This is because it is difficult to control the start of the reaction, so it is difficult to set the timing for raising the temperature of the As supply part, and because the reaction rate is high, the gasification of As to keep the As partial pressure for depressurization constant cannot keep up. is there. When the ampoule is destroyed, not only other components such as boats are destroyed, but also high purity and expensive Ga and As become unusable, which causes great economic damage, and also poisonous As gas and As oxide gas from the ampoule. Is a serious safety issue. Conventionally, there has been no means for effectively solving such a problem. This problem is common not only to GaAs but also to other III-V group compound semiconductors.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, suppress the deformation of the ampoule due to a sudden shortage of the group V element gas in the boat during the synthesis reaction, and manufacture the crystal economically and safely III (EN) A method for synthesizing a -V compound semiconductor composition.

[0012]

DISCLOSURE OF THE INVENTION The present invention is provided in a closed container.
A GaAs melt was synthesized by accommodating As, which is a raw material for a III-V group compound semiconductor composition, for example, a GaAs composition, and Ga put in a boat, and reacting As gas vaporized after heating with liquid Ga. Then, in the method for synthesizing a III-V group compound semiconductor composition for obtaining a GaAs composition from this melt, a fixed ratio of GaAs is contained in Ga contained in the boat.
A polycrystal is added in advance. In Ga, 5% or more, 95% or more of the amount of GaAs melt to be generated
The following GaAs polycrystals are preferably added. If the amount is less than 5%, the synthesis reaction will occur violently and the problem cannot be solved. A stoichiometric composition of G at 95% or more
It does not easily become aAs, or the synthesis reaction is difficult to proceed, which takes time. What is stoichiometry is Ga
And As is a 1: 1 composition. Usually, when a rapid reaction occurs, As is taken in by a chain reaction and G
The formation of aAs results in a stoichiometry composition, but at 95% or more, the reactivity is poor and stoichiometry is less likely to occur. In addition, it takes a long time to make stoichiometry.

The above-mentioned GaAs composition means GaAs single crystal and GaAs polycrystal, and can be applied not only to GaAs single crystal production but also to GaAs polycrystal synthesis. Further, as the III-V group compound semiconductor to which the present invention can be applied, In addition to GaAs, an As-based compound semiconductor (for example, In
There is As). Furthermore, since InP and GaP can be synthesized while maintaining the pressure balance inside and outside the ampoule, they can also be applied to these.

Although an ampoule is usually used as the closed container, it is not necessary to use an ampoule as long as a group V element atmosphere such as As can be formed.

[0015]

When a certain proportion of a group III-V compound semiconductor polycrystal, for example, GaAs polycrystal, is added in advance to a group III element, for example, Ga, accommodated in a boat, a large reaction heat during the reaction between Ga and As occurs. Is absorbed by the heat capacity of GaAs,
Also, by diluting the amount of Ga and As with respect to the total amount,
Since the total heat of reaction can be reduced, the synthetic reaction does not occur rapidly. Therefore, the deformation of the ampoule due to the sudden shortage of As gas in the boat during the synthesis reaction can be suppressed.

[0016]

EXAMPLES Examples of the present invention applied to GaAs will be described below together with comparative examples using Table 1. The conditions of Examples 1-2 and Comparative Examples 1-3 are as follows.

Example 1 The same crystal growth apparatus as in FIG. 1 was used. 170m inside diameter
GaAs was synthesized using a quartz ampoule having a length of 1000 mm. In a quartz boat with a width of 110 mm and a depth of 60 mm, 2,500 g of GaAs polycrystal, which is about 24% of the target 10,373 g of GaAs, and G of 3,795.
A and a were charged in a boat and placed near the end of the synthesis part of the ampoule. The end of the supply part was charged with 4,095 g of As, and the ampoule was evacuated to a vacuum of 10 ⁻⁴ torr and then sealed by welding.

After raising the temperature of the boat to 1238 ° C., the temperature of the As portion was gradually raised to 610 ° C. After a lapse of a certain time after completion of the temperature rise, a GaAs synthesis reaction occurred while emitting a flash of light due to reaction heat, and a melt was formed.

Example 2 The same as Example 1 except for the charge amount of the raw material (Table 1). Approximately 82% of the target 10,367 g of GaAs, that is, 8,500 g of GaAs polycrystal was added.

Comparative Example 1 In the same manner as in Example 1, only the charge amount of the raw material was changed. The quartz boat is charged with only 5,000 g of Ga, and the polycrystalline GaAs is zero. 5,390g of As
After charging and sealing, GaAs was synthesized to form a melt. The formed melt was gradually cooled and solidified, and the composition was estimated from the ratio of the charged Ga and the synthesized GaAs. In the case of 1: 1 composition, GaAs is 10,
It becomes 373 g.

Comparative Example 2 The same as Example 1 except the charge amount of the raw material (Table 1). 415 g of GaAs polycrystal, which is about 4% of the targeted 10,373 g of GaAs, was added.

Comparative Example 3 The same as Example 1 except the charge amount of the raw material (Table 1). 9,970 g of GaAs polycrystal, which is about 96% of the target 10,374 g of GaAs, was added.

[0023]

[Table 1]

As can be seen from Table 1, in Examples 1 and 2, GaAs having a stoichiometric composition could be synthesized without deformation or destruction of the ampoule. In comparative example 1 of the conventional method, ampoule rupture was large, and in comparative example 1 in which the GaAs polycrystal was as small as 4%, ampoule rupture was large. Further, in Comparative Example 3 in which the GaAs polycrystal was as large as 96.1%, it was difficult to obtain a stoichiometry composition, and Ga was excessive on average.

[0025]

According to the present invention, the raw material to be accommodated in the boat
Since a certain proportion of the group III-V compound semiconductor polycrystal is added to the group III element, deformation of the closed container due to a sudden gas shortage of the group V element s in the boat during the synthesis reaction is suppressed, which is economical and safe. Crystals can be produced.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a crystal growth apparatus by a boat method according to an embodiment of the present invention.

[Explanation of symbols]

 1 Ga 2 As 3 Quartz Boat 4 Diffusion Barrier 5 Quartz Ampoule 6 High Temperature Heater 7 Low Temperature Heater

Claims (1)

[Claims] 1. A closed vessel containing a group V element, which is a raw material for a III-V group compound semiconductor composition, and a group III element placed in a boat, and a group V element gas which is vaporized after heating and is in a liquid state. II
In a method for synthesizing a III-V group compound semiconductor composition, a III-V group compound semiconductor melt is synthesized by a reaction with a group I element, and a III-V group compound semiconductor composition is obtained from the melt. A method for synthesizing a III-V compound semiconductor composition, comprising adding 5% to 95% of a III-V compound semiconductor polycrystal of the V compound semiconductor composition to the boat as a raw material.