JP2000313697A - Preparation of oxide single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing an oxide single crystal having a stoichiometric composition at an inexpensive manufacturing cost by using metal Ga. SOLUTION: A raw material mixture 3 comprising metal Ga and an oxide compound is mixed in a dry state. The raw material mixture 3 is contained in a platinum crucible 5, heat-treated in air at about 500 deg.C and successively heat-treated in oxygen at about 1,000 deg.C to form Ga2O3 in the raw material mixture 3 and to prepare a powdery raw material oxide 4. The raw material oxide 4 is baked to prepare a powder crystal 7. The powder crystal 7 is used as a melt by a Czochralski method to pull a oxide single crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an oxide single crystal used as an optical material.

[0002]

2. Description of the Related Art Oxide materials such as ceramics and oxide single crystals are indispensable in the field of electronic devices. Ceramics are used as packages and piezoelectric ceramics, and oxide single crystals are used as key devices for a wide range of electronics such as piezoelectric devices, laser devices, and other optical applications. In general, the oxide single crystal is made of a complex oxide containing oxygen, and research and development aiming at high quality and new functions having properties different from those of conventional ones have been actively conducted. For example, Y-Al garnet (hereinafter referred to as YA
G), Li-Ta-O (hereinafter, referred to as LT) and Li-Nb-O (hereinafter, referred to as LN) are typical oxide single crystals.

[0003] Also, "Sov. Phys. Dokl.2"
7 (6), June 1982, 434. B. V. Mi
As described in ll et al ", Ca ₃ G
Numerous substituted materials having the same structure as a ₂ Ge ₄ O ₁₄ have been found and are expected to be applied as piezoelectric materials having new functions. In particular, La ₃ Ga ₅ SiO ₁₄ and La ₃ Ta _0.5 Ga
Oxide single crystals containing Ga such as _5.5 O ₁₄ and La ₃ Nb _0.5 Ga _5.5 O ₁₄ are urgently developed as communication devices for digital applications. Usually, La ₂ O ₃ , Ga ₂ O ₃ , SiO ₂ , Ta ₂ O ₅ and Nb oxide are used as raw materials for producing these oxide single crystals.

[0004]

However, in the production of these oxide single crystals, a large amount of Ga ₂ O ₃ is consumed. Since Ga ₂ O ₃ has a high unit price, there has been a problem that the production cost of these oxide single crystals is increased. On the other hand, since metal Ga is relatively inexpensive, if the metal Ga is oxidized to produce Ga ₂ O ₃ to produce an oxide single crystal, the production cost can be reduced.

[0005] In the following, La ₃ Ta _0.5
A method for producing Ga _5.5 O ₁₄ will be described. First, after heating and melting the metal Ga to a temperature equal to or higher than the melting point (about 30 ° C.), the La ₂ O ₃ powder and the Ta ₂ O ₅ powder are put into a mortar to prepare a raw material mixture. Thereafter, the raw material mixture is put into a platinum crucible, heated to about 1000 ° C. in the air, and a reaction between the raw material mixtures is performed together with oxidation of the metal Ga, whereby powdery La ₃ Ta _0.5 Ga _5.5 O ₁₄ is removed. Make it. Further, using the powdery La ₃ Ta _0.5 Ga _5.5 O ₁₄ as a melt, the crystal is pulled up by the Czochralski method to produce a La ₃ Ta _0.5 Ga _5.5 O ₁₄ single crystal.

When the oxidation of metal Ga is performed in air as described above, the oxygen in the air is not sufficiently large.
The whole is not oxidized, and unreacted metal Ga is formed. Also, Ga ₂ O is formed in addition to Ga ₂ O _3, the Ga ₂ O
Is volatile and is released into the air. Thus, powdery La ₃ Ta _0.5 Ga _5.5 O ₁₄ becomes a composition Ga is _{insufficient, La 3 Ta 0.5 Ga 5. 5} O 14 single crystal which is manufactured by performing the pulling of the crystal by Czochralski Stoichiometric composition cannot be obtained. To solve this problem,
It was considered that the reaction of the raw material mixture was carried out in pure oxygen together with the oxidation of metal Ga. In this case, since the oxygen is active, violently reacts with the metal Ga, without forming a Ga ₂ O, to form a Ga ₂ O ₃ at an accelerated rate. The temperature generated by the reaction heat is about 1800 ° C., and the melting point of the platinum crucible is 1770 ° C., which causes a problem that the platinum crucible is melted.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an oxide single crystal having a stoichiometric composition at a low manufacturing cost by using metal Ga. It is intended to provide a manufacturing method.

[0008]

According to the present invention, there is provided an oxide single crystal of the present invention.
The first invention in the manufacturing method is a method in which powdery metal Ga and
After dry-mixing the raw material mixture consisting of oxidized compounds,
In a heat treatment temperature of about 500 ° C.
Heat treatment at a temperature of about 1000 ° C.
Ga in the raw material mixture_TwoO_ThreeTo form a powdery raw material
After preparing the oxide, the raw material oxide is fired to form powder.
A crystal is prepared, and the powder crystal is prepared by the Czochralski method.
Can be used as a melt to pull up an oxide single crystal.
And features. The second invention relates to a powdery metal Ga and
After dry-mixing the raw material mixture composed of the oxidized compound,
Put the above mixture in a crucible and heat-treat in air
Heat treatment at a temperature of 1300 ° C. to 1400 ° C.,
Ga in the raw material mixture_TwoO_ThreeTo form a powdery raw material
After preparing the oxide, the raw material oxide is fired to form powder.
A crystal is prepared, and the powder crystal is prepared by the Czochralski method.
Can be used as a melt to pull up an oxide single crystal.
And features. The third invention relates to a powdery metal Ga and
After dry-mixing the raw material mixture composed of the oxidized compound,
Put the above mixture in a crucible and heat-treat in air
Heat treatment at a temperature of 1300 ° C. to 1400 ° C.
Ga in the feed mixture_TwoO_ThreeAs well as powdered raw acid
After the oxide is produced, the raw material oxide is
Baking at heat treatment temperature 1450 ℃ ~ 1500 ℃
Crystals are prepared and the powder is compacted by the Czochralski method.
Of oxide single crystal using crystal as melt
It is characterized by the following. According to a fourth aspect of the present invention,
In the method for producing an oxide single crystal of
Things are La_ThreeTa_0.5Ga_5.5O₁₄, La_ThreeGa_FiveSi
O₁₄, La_ThreeNb _0.5Ga_5.5O₁₄Be one of
It is characterized by.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the first embodiment of the present invention,
La ₃ T which is a typical oxide single crystal using metallic Ga
a _0.5 Ga _5.5 O ₁₄ (hereinafter, referred to LTGs) will be described with reference to FIG. 1 below manufacturing method. FIG. 1 is a process chart showing a manufacturing method according to the first embodiment of the present invention. First, as shown in FIG. 1A, purity 4N (99.99)
%) La ₂ O ₃ powder, Ta ₂ O ₅ powder and purity 6N (9%).
9.9999%) metal Ga powder (particle size: 1 mm to 5 m)
m) was determined to be 146.6 g, 33.1 g and 11 respectively.
Weigh 5.0 g. The metal Ga was put into the mortar 1 previously kept at about 60 ° C. to prepare a Ga melt, and the La melt was added to the Ga melt.
₂ O ₃ powder and Ta ₂ O ₅ powder are added. As described above, since the melting point of metallic Ga is about 30 ° C., this Ga melt is completed in about several minutes. Further, as shown in FIG. 1 (B), La is used together with the Ga melt in a mortar 1 using a pestle 2.
_A raw material mixture 3 is prepared by dry-mixing ₂ O ₃ powder and Ta ₂ O ₅ powder.

Next, as shown in FIG. 1 (C), the raw material mixture 3 is placed in a platinum crucible 5 and subjected to a heat treatment at a predetermined temperature in a predetermined atmosphere gas to produce a raw material oxide 4. The size of the platinum crucible is 10 mm in width and 15 m in length.
m, depth 5 mm.

Here, in the heat treatment, air or pure oxygen (100%) and air and pure oxygen are used in combination as an atmosphere gas, and the heat treatment temperature is changed in a range of about 400 ° C. to about 1000 ° C. Then, the raw material mixture 3 is subjected to a heat treatment to produce the raw material oxides 4 of the samples 1 to 7,
The optimum production conditions of the raw material oxide 4 in which all of the metal Ga was changed to Ga ₂ O ₃ without causing damage to the platinum crucible 5 were examined. It can be seen that all the metal Ga has changed to Ga ₂ O ₃ as follows. That is, La in the raw material mixture 3
_{The 2} O ₃ powder and the Ta ₂ O ₅ powder do not change by the heat treatment, but the metal Ga changes to Ga ₂ O ₃ , so that the raw material mixture 3
And the material oxide 4 causes a weight change. Since it is theoretically known that the weight ratio of the raw material oxide 4 to the raw material mixture 3 is + 13%, if the weight of the raw material oxide 4 is increased by + 13% from the weight of the raw material mixture 3, It can be seen that all of the metal Ga has changed to Ga ₂ O ₃ .
Table 1 shows the results. Table 1 is a table showing the weight ratio of the raw material oxide and the broken state of the platinum crucible when the atmosphere gas for processing the raw material mixture and the heat treatment temperature were changed.

[0012]

[Table 1]

In Table 1, the weight ratio is the weight of the raw material oxide 4 with respect to the weight of the raw material mixture 3. Sample 1 was prepared by mixing the raw material mixture 3 at a heat treatment temperature of 400 ° C. using air as an atmospheric gas.
In this case, the weight ratio did not change, and the platinum crucible 5 was not damaged. From this, the metal Ga
No oxidation was performed, and it was found that Ga ₂ O ₃ was not formed. Sample 2 was a case in which the raw material mixture 3 was heat-treated at a heat treatment temperature of 470 ° C. using air as the atmospheric gas. The weight ratio was + 7%, and the platinum crucible 5 was not damaged. Sample 3 was a case where the raw material mixture 3 was heat-treated at a heat treatment temperature of 500 ° C. using air as an atmospheric gas. The weight ratio was + 8%, and the platinum crucible 5 was not damaged. As described above, in the samples 2 and 3, the metal Ga was oxidized, but not all of the metal Ga became Ga ₂ O ₃ .
It can be seen that there is unreacted metal Ga.

Sample 4 was a case where the raw material mixture 3 was heat-treated at a heat treatment temperature of 1000 ° C. using air as an atmospheric gas. The weight ratio was + 5%, and the platinum crucible 5 was not damaged. Unreacted metal G as in samples 2 and 3
It can be seen that there is a, but the weight ratio is smaller than that of Samples 2 and 3. This is considered to be because Ga ₂ O was formed and evaporated due to insufficient supply of oxygen to the metal Ga. Sample 5 is a case where the raw material mixture 3 was heat-treated at a heat treatment temperature of 500 ° C. using pure oxygen (100%) as an atmosphere gas. The weight ratio was + 10%, and the platinum crucible 5 was partially damaged. was there. Metal Ga is
It can be seen that most of them are oxidized to form Ga ₂ O ₃ , but are still insufficient. If there is a large amount of oxygen, metal G
a rapidly reacts with oxygen to generate rapid heat generation, and the temperature generated by this heat generation corresponds to the melting point of the platinum crucible 5 (1770).
C.) or more, it is considered that the platinum crucible 5 was damaged.

Sample 6 is composed of pure oxygen (10
0%) and heat treatment of the raw material mixture 3 at a heat treatment temperature of 1000 ° C., the weight ratio was + 13%, and the platinum crucible 5 was partially damaged. Sample 7 was prepared by first heat-treating the raw material mixture 3 at a heat treatment temperature of 500 ° C. using air as the atmosphere gas and then using pure oxygen (100%) as the atmosphere gas at a heat treatment temperature of 1000 ° C. In the case where the raw material mixture 3 was heat-treated, the weight ratio was + 13%, and the platinum crucible 5 was not damaged. From the above, the raw material mixture 3 is heat-treated at a heat treatment temperature of about 500 ° C. using air as an atmosphere gas, and then pure oxygen (100%) is used as the atmosphere gas and the heat treatment temperature is about 100 ° C.
When the heat treatment is performed at 0 ° C., the optimal raw material oxide 4 in which all of the metal Ga is changed to Ga ₂ O ₃ can be obtained without damaging the platinum crucible 5.

Next, as shown in FIG. 1 (D), the raw material oxide 4 prepared under the conditions of the sample 7 is placed in a ceramic dish 6, heated to a temperature of 1470 ° C., and fired in air. , Powder crystal 7 was produced. When this powder crystal 7 was analyzed by X-ray diffraction, an LTG peak was observed. LTG
It was confirmed that a powder was obtained. Further, the powder crystal 7 was made to have an outer diameter of 50 m by the Czochralski method described later.
m, and melted in a crucible 12 having a height of 50 mm, and the crystal was pulled up to obtain an LTG single crystal 14.

In the first embodiment of the present invention, the raw material oxide 4
The platinum crucible 5 was used when manufacturing the
Instead, an alumina crucible may be used. Alumina is less likely to react with Ga at high temperatures than platinum, and the unit price is lower. For this reason, production costs can be significantly reduced. Next, a second embodiment of the present invention using a crucible made of alumina instead of the platinum crucible 5 will be described with reference to FIG. FIG. 2 is a process chart showing a manufacturing method according to the second embodiment of the present invention.

The raw material mixture 3 is placed in a mortar 1 by performing the same steps as in FIGS. 1A and 1B shown in the first embodiment of the present invention.
Is prepared. Next, as shown in FIG. 2, the raw material mixture 3 is placed in an alumina crucible 16 and subjected to a heat treatment at a predetermined temperature in a predetermined atmosphere gas to produce a raw material oxide 4. Here, in the heat treatment, air is used as an atmosphere gas,
The heat treatment of the raw material mixture 3 was performed by changing the heat treatment temperature in the range of 1000 ° C. to 1480 ° C., and samples 1 to 5
The raw material oxide 4 was manufactured, and the optimum conditions for forming the raw material oxide 4 in which all of the metal Ga changed to Ga ₂ O ₃ were examined. Table 2 shows the results. Table 2 is a table showing the weight ratio of the raw material oxide and the state when the heat treatment temperature of the raw material mixture was changed. The atmosphere gas for processing the raw material mixture was air, and the heat treatment time was all 2 hours.

[0019]

[Table 2]

In Table 2, the weight ratio is the weight of the raw material oxide 4 with respect to the weight of the raw material mixture 3. Sample 1 was a case where the raw material mixture 3 was heat-treated at a heat treatment temperature of 1000 ° C., the weight ratio was + 7%, and the raw material oxide 4 was in a powder state. Sample 2 is a case where the raw material mixture 3 was heat-treated at a heat treatment temperature of 1200 ° C., and the weight ratio was +11.
%, And the raw material oxide 4 was in a powder state. As described above, in the samples 1 and 2, the metal Ga was oxidized, but not all of the metal Ga became Ga ₂ O ₃ , and the unreacted metal G
It can be seen that there is a.

Sample 3 is a case where the raw material mixture 3 was heat-treated at a heat treatment temperature of 1300 ° C., and the weight ratio was +13.
%, And the raw material oxide 4 was in a powder state. Sample 4
Is a case where the raw material mixture 3 was heat-treated at a heat treatment temperature of 1400 ° C., the weight ratio was + 13%, and the raw material oxide 4 was in a powder state. Sample 5 has a heat treatment temperature of 148.
In the case where the raw material mixture 3 was heat-treated at 0 ° C., the weight ratio was + 13%, and the raw material oxide 4 was in a sintered state. Here, the sintering state is a state in which the raw material oxide 4 is solidified. Powder crystal 7 is prepared from sintered oxide 4 and powder crystal 7 is used as melt 13 when pulling up LTG single crystal 14 to be described later. Because it does not reach the inside of, a different phase occurs. For this reason, a good quality LTG single crystal 14 cannot be obtained.

From the above, the raw material mixture 3 is air as the atmospheric gas, and the heat treatment temperature is 1300 ° C. to 140 ° C.
When the heat treatment is performed at 0 ° C., it is possible to obtain the optimum raw material oxide 4 in which all the metal Ga is changed to Ga ₂ O ₃ , and a good LT
An optimal melt 13 for producing the G single crystal 14 can be obtained.

Next, as in the first embodiment of the present invention shown in FIG. 1 (D), the raw material oxide 4 prepared under the conditions of the samples 3 and 4 is placed in the ceramic dish 6, and the heat treatment temperature is 1470 ° C.
And fired in the air to produce powder crystal 7. When this powder crystal 7 was analyzed by X-ray diffraction, LT
G peak is observed. It was confirmed that LTG powder was obtained. Further, the powder crystal 7 was melted into an iridium crucible 12 having an outer diameter of 50 mm and a height of 50 mm by a Czochralski method described later, and the single crystal was pulled up to obtain an LTG single crystal 14.

At this time, when a large amount of powder crystal 7 is required to obtain a large LTG single crystal 14, the volume of powder crystal 7 becomes large. It is required to make it twice. The productivity can be improved as the number of productions of the powder crystal 7 decreases. Therefore, these samples 3 and 4 are shown in FIG.
Placed in a ceramic dish 6 as shown in FIG.
When the powder crystal 7 was manufactured by firing at 450 ° C. to 1500 ° C., it was experimentally confirmed that the volume of the powder crystal 7 was reduced.

As described above, air is used as the raw material mixture 3 as the atmospheric gas, and the heat treatment temperature is 1300 ° C. to 1400 ° C.
Heat treatment at 1450 ° C. to 1500 ° C. in oxygen to produce the powder crystal 7, compared to the case where only heat treatment was performed at a heat treatment temperature of 1300 ° C. to 1400 ° C. Can be reduced to approximately 体積. As a result, the number of powder crystals 7 to be put into crucible 12 for pulling single crystal of LTG 14 can be reduced, so that productivity is improved.

Here, LTG by the Czochralski method
A method for manufacturing a single crystal is described with reference to FIGS. FIG.
FIG. 1 is a cross-sectional view of a high-frequency induction heating type Czochralski furnace used for producing an LTG single crystal. As shown in FIG. 3, the Czochralski furnace 8 includes a high-frequency coil 1 for heating.
A crucible 12 made of iridium (Ir), which is surrounded by a plurality of heat retaining cylinders 11 and contains a melt 13, is provided inside the quartz tube 9.
The heights of the upper end of the high-frequency coil 10 and the upper end of the crucible 12 are almost uniform.

As the size of the crucible 12, for example, a crucible having an inner diameter approximately twice as large as the diameter of the crystal to be produced is used. At the upper center of the quartz tube 9 is provided a pulling rod 15 that rotates at a constant speed and is pulled up at a constant speed. The method for producing the LTG single crystal 14 is performed as follows. The powder crystal 7 is put in the crucible 12 and is melted by heating to produce a melt 13. The heating temperature at this time is about 1500 ° C. Next, the seed crystal of the LTG 14 was fixed to the lower end of the pulling rod 15, and
While slowly rotating at a rotation speed of 0 to 20 rpm, the seed crystal is pulled up at a speed of 1 to 3 mm / h, and L
A TG single crystal 14 is produced.

As described above, powdered metal Ga and La
_{After the} raw material mixture 3 composed of ₂ O ₃ powder and Ta ₂ O ₅ powder is dry-mixed, the raw material mixture 3 is placed in a platinum crucible 5 and heat-treated in air at a heat treatment temperature of about 500 ° C.
A heat treatment is performed in pure oxygen (100%) at a heat treatment temperature of about 1000 ° C. to form Ga ₂ O ₃ and produce a raw material oxide 4, which is then fired to form a powder crystal 7. Since the LTG single crystal 14 is pulled up by using the powder crystal 7 as the melt 13 by the Czochralski method, it is not necessary to use expensive Ga ₂ O ₃ , so that LTG is manufactured at low cost. be able to. The raw material price of the LTG single crystal 14 manufactured in this manner can be reduced to about half that in the case of using the conventional Ga ₂ O ₃ as a raw material.

The raw material mixture 3 is placed in an alumina crucible and heat-treated in air at a heat treatment temperature of 1300 ° C. to 1400 ° C. to form Ga ₂ O ₃ in the raw material mixture _{3 and} to form a powdery raw material oxide. After preparing the raw material oxide 4, the raw material oxide 4 is fired to prepare a powder crystal 7, and the powder crystal 7 is used as a melt 13 by the Czochralski method to obtain an LT.
Since the single crystal of G14 is pulled, expensive Ga ₂ O ₃
Therefore, the LTG single crystal 14 can be manufactured at low cost.

[0030] The raw material mixture 3 was placed in an alumina crucible, using air as the atmospheric gas, and subjected to heat treatment at a heat treatment temperature 1300 ° C. to 1400 ° C., Ga ₂ to the raw material mixture 3
After the formation of O ₃ and the preparation of the powdered raw material oxide 4, the raw material oxide 4 is subsequently calcined in oxygen at a heat treatment temperature of 1450 ° C. to 1500 ° C. to prepare a powder crystal 7. The powder crystal 7 is melted by the ski method 1
Since the LTG single crystal 14 is used to pull up the LTG single crystal 3, the volume of the powder crystal 7 can be reduced, so that the number of powder crystals 7 put in the crucible 12 can be reduced,
Productivity is improved.

Similarly, metal Ga, CaCO_Three
And GeO_TwoUsing Ca_ThreeGa_TwoGe _FourO₁₄, Metal Ga,
La_TwoO_ThreeAnd SiO_TwoUsing La_ThreeGa_FiveSiO₁₄,Money
Genus Ga, La_TwoO_ThreeAnd Nb_TwoO_FiveUsing La_ThreeNb_0.5G
a_5.5O₁₄Can be manufactured at low cost. Also metal
Ga and Gd_TwoO_ThreeUsing Gd-Ga garnet (GG
G) and metal Ga, Gd_TwoO_ThreeAnd Y_TwoO_ThreeUsing Gd-Y
-Has a garnet structure of Ga garnet (GYGG)
Can be produced at low cost.

[0032]

According to the method for producing an oxide single crystal of the present invention, after a raw material mixture composed of powdered metal Ga and an oxide compound is dry-mixed, the raw material mixture is placed in a platinum crucible, and the mixture is placed in air. A heat treatment is performed at a heat treatment temperature of about 500 ° C., and subsequently, a heat treatment is performed in oxygen at a heat treatment temperature of about 1000 ° C. to form Ga ₂ O ₃ in the raw material mixture and to prepare a powdery raw material oxide. This raw material oxide is fired to produce powder crystals, and the oxide single crystal is pulled up by the Czochralski method using the powder crystals as a melt, so that expensive Ga ₂ O ₃ must be used. Therefore, an oxide single crystal can be manufactured at low cost. Further, after the raw material mixture composed of powdered metal Ga and an oxide compound is dry-mixed, the raw material mixture is put into an alumina crucible, and is subjected to a heat treatment temperature of 1300 ° C. to 1400 ° C. in air.
C. to form Ga ₂ O ₃ in the raw material mixture and produce a powdery raw material oxide. Then, the raw material oxide is baked to produce powder crystals, which are produced by the Czochralski method. Since the oxide single crystal is pulled up using the powder crystal as a melt, it is not necessary to use expensive Ga ₂ O ₃ , so that the oxide single crystal can be manufactured at low cost. Furthermore, after the raw material mixture composed of the powdered metal Ga and the oxide compound is dry-mixed, the raw material mixture is placed in an alumina crucible, and a heat treatment temperature of 1300 in air.
After performing heat treatment at 1 to 1400 ° C. to form Ga ₂ O ₃ in the raw material mixture and to prepare a powdery raw material oxide, the raw material oxide is subsequently subjected to a heat treatment temperature of 1450 ° C. to 1500 ° C. in oxygen. The powder crystal is produced by baking in the same manner, and the oxide single crystal is pulled up by the Czochralski method using the powder crystal as a melt, so that the volume of the powder crystal can be reduced. The number of the powder crystals to be put into the crucible containing the liquid can be reduced, and the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a process chart showing a manufacturing method according to a first embodiment of the present invention.

FIG. 2 is a process chart showing a manufacturing method according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a high frequency induction heating type Czochralski furnace used for producing an LTG single crystal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mortar, 2 ... pestle, 3 ... Raw material mixture, 4 ... Raw material oxide, 5 ... Platinum crucible, 6 ... Ceramic dish, 7 ... Powder crystal, 8 ... Czochralski furnace, 9 ... Quartz tube, 10 ... High frequency coil , 11 ... insulated cylinder, 12 ... crucible, 13 ... melt,
14: LTG single crystal, 15: pulling rod, 16: alumina crucible

Claims (4)

[Claims] 1. A raw material mixture composed of powdered metal Ga and an oxide compound is dry-mixed, and then the raw material mixture is placed in a platinum crucible and heat-treated at a heat treatment temperature of about 500 ° C. in air. A heat treatment is performed at a heat treatment temperature of about 1000 ° C. to form Ga ₂ O ₃ in the raw material mixture and to prepare a powdery raw material oxide. A method for producing an oxide single crystal, wherein the oxide single crystal is pulled up by a Czochralski method using the powder crystal as a melt. 2. A raw material mixture composed of powdered metal Ga and an oxide compound is dry-mixed, and then the raw material mixture is placed in an alumina crucible and heat-treated at a heat treatment temperature of 1300 ° C. to 1400 ° C. in air. Ga in the raw material mixture
_After forming ₂ O ₃ and preparing a powdery raw material oxide, the raw material oxide is fired to prepare powder crystals, and the powder crystals are used as a melt by the Czochralski method to obtain an oxide. A method for manufacturing an oxide single crystal, comprising pulling the single crystal. 3. A raw material mixture composed of powdered metal Ga and an oxide compound is dry-mixed, and then the raw material mixture is placed in an alumina crucible and heat-treated at a heat treatment temperature of 1300 ° C. to 1400 ° C. in air. Ga _{2 in the} mixture
After the formation of O ₃ and the preparation of a powdery raw material oxide, the raw material oxide was subsequently subjected to a heat treatment temperature of 1 in oxygen.
Firing at 450 to 1500 ° C. to produce powder crystals,
A method for producing an oxide single crystal, wherein the oxide single crystal is pulled up by a Czochralski method using the powder crystal as a melt. 4. The powder crystal according to claim 1, wherein_ThreeTa_0.5Ga_5.5O
₁₄, La_ThreeGa_FiveSiO₁₄, La_ThreeNb _0.5Ga_5.5O₁₄of
4. The method as claimed in claim 1, wherein said first or second means is any one of the following.
Method for manufacturing oxide single crystal.