WO2014091969A1

WO2014091969A1 - Single-crystal production device, single-crystal production method using said device, and single crystal produced using said method

Info

Publication number: WO2014091969A1
Application number: PCT/JP2013/082495
Authority: WO
Inventors: 守道渡邊; 克宏今井; 吉川　潤; 潔松島; 聡太大河内
Original assignee: 日本碍子株式会社
Priority date: 2012-12-14
Filing date: 2013-12-03
Publication date: 2014-06-19
Also published as: JPWO2014091969A1

Abstract

In a single-crystal production device wherein a spraying means and a heating means are disposed facing each other with a seed substrate therebetween, a single crystal is produced from a powder by implementing: a film formation step in which the spraying means is used to spray the starting material powder towards the seed substrate to form a film upon a surface of the seed substrate; and a heating step in which the heating means is used to heat the film formed upon the surface of the seed substrate. As a result, a single-crystal production device is provided which exhibits excellent productivity, and which is capable of producing high-quality single crystals having few pores, even when using materials with which molten starting material is difficult to obtain.

Description

Single crystal manufacturing apparatus, single crystal manufacturing method using the apparatus, and single crystal manufactured by the method

The present invention relates to a single crystal manufacturing apparatus. More specifically, the present invention relates to a single crystal manufacturing apparatus capable of manufacturing a homogeneous single crystal with few pores with high productivity. The present invention also relates to a single crystal manufacturing method using such a single crystal manufacturing apparatus. Furthermore, the present invention also relates to a single crystal manufactured by such a single crystal manufacturing method.

For example, piezoelectric materials used for piezoelectric actuators used in various applications such as piezoelectric pumps and ink-jet printer ink heads, and various semiconductor elements such as light-emitting diodes (LEDs) and laser diodes (LDs). As the semiconductor material to be used, various inorganic materials such as ceramics are used. In order to improve the performance of such inorganic materials, it is known that it is important to increase the degree of crystal orientation in these inorganic materials.

For example, in piezoelectric ceramics, in order to exert a higher piezoelectric effect, a process for aligning the direction of electric dipoles in the crystal by applying an electric field to the piezoelectric ceramics (polarization process) is performed. The higher the degree of crystal orientation, the easier it is to polarize. As a result, high piezoelectric performance can be obtained.

By the way, as a method of forming a single crystal film or an alignment film including a film in which crystals are oriented to some extent (hereinafter sometimes referred to as “orientation film”), a single crystal or an oriented polycrystal to be produced is prepared. There is a method in which a raw material melt for a film is prepared and crystallized on a seed single crystal. However, raw materials such as oxides (such as zinc oxide (ZnO)), nitrides (such as gallium nitride (GaN)), and carbides (such as silicon carbide (SiC)) used in such a method are extremely May have a high melting point or may be easily decomposed. For such a raw material, it is difficult to obtain a raw material melt, and it has been difficult to apply the above method to such a material system. Therefore, for example, when a single crystal of GaN is to be produced, a Na flux method has been proposed in which a raw material is dissolved using sodium (Na) as a flux and precipitated into seeds to obtain a single crystal (for example, Patent Documents). 1). In addition, a GaN layer is formed on a heterogeneous substrate such as sapphire using a hydride vapor phase epitaxy, and the heterogeneous substrate is removed after the growth of the GaN layer, whereby a self-standing GaN single crystal substrate is formed. A method of obtaining is proposed (see, for example, Patent Document 2). However, these prior art methods have the problem that the crystal growth rate is slow.

On the other hand, a single crystal film and an orientation film can also be manufactured by a solid phase growth method (see, for example, Patent Document 3). Specifically, for example, it is disclosed that a single crystal or oriented polycrystal composed of an oxide having a perovskite structure and having a porosity of 0.01 to 8% by volume can exhibit excellent characteristics as a piezoelectric material or the like. Has been. In addition, it includes oriented polycrystals or crystal grains that form a predetermined number of low-angle grain boundaries per unit area by heat-treating a compact or sintered body of oxide powder having a specific composition at a predetermined temperature. It has been disclosed to efficiently produce a high-quality oxide ion conductive crystal substantially composed of a single crystal (see, for example, Patent Document 4).

In addition, in Patent Documents 3 and 4, as one method for producing a crystal, the contact portion is heated while the sintered body and the single crystal (seed substrate) are in contact with each other, and the other ends are also produced. It is disclosed that a predetermined temperature gradient is generated by performing temperature control for cooling a portion, and a polycrystalline sintered body is single-crystallized or oriented starting from a seed substrate (for example, Patent Document 3). 4 and FIG. 4 of Patent Document 4).

However, there are concerns about the following problems in the orientation of crystals by such solid phase growth. First, in order to bring the sintered body particles into the single crystal of the seed substrate by bringing the sintered body and the seed substrate into contact with each other and heating the contact portion as described above, solid phase growth is performed. The substrate surface is mirror-polished, the sintered body and the seed substrate are pressed into contact with each other, or a liquid phase material is filled in the interface so that there is no void at the interface between the two, and the two are brought into close contact with each other. This is very important. This complicates the manufacturing process and the manufacturing apparatus. In particular, it is extremely difficult to make a large-area sintered body and the seed substrate adhere to each other uniformly.

Also,
In the above prior art, a predetermined temperature gradient is generated by heating the contact portion between the polycrystalline sintered body and the seed substrate and cooling the other end region of the sintered body. Is small, solid phase growth occurs at the interface between the sintered body and the seed substrate, but grain growth progresses separately for each individual particle within the sintered body away from the interface. As a result, as the solid phase growth proceeds, the particles taken into the seed crystal become coarse, and finally the solid phase growth stops. Further, since coarse particles are separately taken into the seed crystal, pores are likely to remain in the film. On the other hand, if the temperature gradient is excessive to prevent such a problem, the workpiece itself may be damaged.

Therefore, in this technical field, the particle size of the raw material powder (raw material powder) is increased by the aerosol deposition method (hereinafter sometimes referred to as “AD method”) so that the particle size gradually increases with distance from the seed substrate. Of producing a high-quality single crystal film or oriented polycrystalline film by spraying raw material powders of different quality onto a seed substrate, depositing on the seed substrate, and heat-treating the film containing the raw material thus formed Is disclosed (for example, see Patent Document 5).

However, the manufacturing method of the single crystal film and the oriented polycrystalline film according to the above prior art is very complicated as described above and takes time. In addition, it is added to the film of raw material powder to shift the solid solution impurities mixed in the raw material powder and the orientation temperature to the lower temperature side in order to control the direction of solid phase growth and control the orientation of crystal grains. It is extremely difficult to accurately control the concentration distribution of the sintering aid in the film as intended, and it is difficult to obtain homogeneous crystals. Similarly to the methods described in Patent Documents 3 and 4, since particles existing in a region away from the interface between the film and the seed substrate grow into coarse particles by heat treatment, they are very large for solid phase growth. Energy is required and eventually solid phase growth stops. Further, since coarse particles are separately taken into the seed crystal, pores are likely to remain in the film. Further, in any of the above-described methods for producing a single crystal film and an oriented polycrystalline film, the production of the film and the heating of the film are performed by separate apparatuses. Therefore, the manufacturing process and the manufacturing means of the single crystal film become complicated, and there is a possibility of causing problems such as an increase in manufacturing cost.

By the way, in this technical field, it is a method of forming a ceramic film structure on a substrate using the AD method, and after film formation by the AD method (hereinafter sometimes referred to as “AD film formation”) or AD A method for improving film quality while suppressing the influence of heat treatment on a substrate by performing heat treatment by infrared laser irradiation during film formation has been proposed (see, for example, Patent Document 6 and Non-Patent Document 1).

The above method is not intended to be single crystallization by the epitaxial growth method, but for the purpose of improving film quality such as crystallinity, for example. Further, in the above method, since an infrared laser as a heat source is irradiated from the surface side of the film (opposite side of the substrate), a temperature gradient is generated inside the ceramic film structure so as to become a low temperature as it approaches the substrate. . However, in such a method, grain growth on the surface side of the film (distant from the interface) is given priority over solid phase growth at the interface between the film and the seed substrate. Will eventually be required and solid phase growth will eventually cease. Further, since coarse particles are separately taken into the seed crystal, pores are likely to remain in the film. That is, the heating mode in the above method is not necessarily suitable for single crystallization of the raw material powder.

In addition, in the above method, heating by infrared laser irradiation can be performed during AD film formation, but when the infrared laser irradiation is performed during film formation, the film formation chamber is filled with aerosol. Since the laser light is easily scattered, there is a problem that it is difficult to effectively irradiate the raw material powder with the laser light.

As described above, there is a need in the art for a single crystal manufacturing apparatus with excellent productivity that can produce a high-quality single crystal with few pores even in a material system in which it is difficult to obtain a raw material melt. .

US Pat. No. 5,868,837 JP 2003-178984 A JP 2003-267996 A Japanese Patent No. 3985144 Japanese Patent No. 4668254 Japanese Patent No. 4538609

As described above, there is a need in the art for a single crystal manufacturing apparatus with excellent productivity that can produce a high-quality single crystal with few pores even in a material system in which it is difficult to obtain a raw material melt. . The present invention has been made to meet such a demand. That is, an object of the present invention is to provide a single crystal production apparatus excellent in productivity capable of producing a high-quality single crystal having few pores even in a material system in which it is difficult to obtain a raw material melt. .

One object of the present invention is to
A raw material powder is sprayed toward the seed substrate to deposit the powder on the surface of the seed substrate, and an injection means for forming a film, and the film deposited on the surface of the seed substrate is heated. Heating means,
With
A film forming step of forming a film by spraying the powder toward the seed substrate by the spraying means to deposit the powder on the surface of the seed substrate, and a surface of the seed substrate by the heating means A heating step for heating the film formed thereon;
A single crystal production apparatus for producing a single crystal from the powder by executing
The spraying means and the heating means are arranged to face each other across the seed substrate;
It is achieved by a single crystal manufacturing apparatus characterized by the following.

The single crystal manufacturing apparatus according to the present invention can produce a high-quality single crystal with few pores with high productivity even in a material system in which it is difficult to obtain a raw material melt.

It is an example of the typical block diagram which shows the outline of a structure of the single crystal manufacturing apparatus 20 which concerns on one embodiment of this invention.

As a result of diligent research to achieve the above object, the present inventor sprays raw material powder onto the seed substrate by spraying means to deposit the powder on the surface of the seed substrate, thereby forming a film. In the single crystal manufacturing apparatus for producing a single crystal from powder by executing the step and the heating step of heating the film formed on the surface of the seed substrate by the heating means, the injection means and the heating means are seeded. By arranging them so as to face each other across the substrate, we found that even in a material system where it is difficult to obtain a raw material melt, a high-quality single crystal with few pores can be produced with high productivity, The present invention has been conceived.

That is, the first embodiment of the present invention is:
A raw material powder is sprayed toward the seed substrate to deposit the powder on the surface of the seed substrate, and an injection means for forming a film, and the film deposited on the surface of the seed substrate is heated. Heating means,
With
A film forming step of forming a film by spraying the powder toward the seed substrate by the spraying means to deposit the powder on the surface of the seed substrate, and a surface of the seed substrate by the heating means A heating step for heating the film formed thereon;
A single crystal production apparatus for producing a single crystal from the powder by executing
The spraying means and the heating means are arranged to face each other across the seed substrate;
Is a single crystal manufacturing apparatus.

As described above, the single crystal manufacturing apparatus according to the present embodiment includes a spraying unit that sprays a raw material powder toward a seed substrate, deposits the powder on the surface of the seed substrate, and forms a film. And heating means for heating the film formed on the surface of the seed substrate. Thereby, in the single crystal manufacturing apparatus according to this embodiment, the powder is deposited on the surface of the seed substrate by spraying the powder toward the seed substrate by the spraying means to form a film. A single crystal can be produced from the powder by performing a film forming step and a heating step of heating the film formed on the surface of the seed substrate by the heating means. The main component of the substance for obtaining a single crystal by the method for producing a single crystal according to this embodiment is not particularly limited. For example, various ceramics, oxides such as zinc oxide (ZnO), gallium nitride (GaN), etc. (The details will be described later).

The injection means may have any configuration as long as the raw material powder can be injected toward the seed substrate to deposit the powder on the surface of the seed substrate. Specifically, the injection means is, for example, an injection nozzle for injecting the raw material powder toward the seed substrate in the aerosol deposition method (AD method), the powder jet deposition method (PJD method), or the like. Can be included.

Further, the heating means may be a heating means having any configuration as long as the film formed on the surface of the seed substrate can be heated to grow a single crystal from the film. Typically, the heating means includes, for example, an infrared lamp (for example, a near infrared lamp), various lasers (for example, a CO ₂ laser, a YAG laser, an excimer laser, a semiconductor laser, etc.), a high-frequency heating device, and the like. Can be mentioned.

In the single crystal manufacturing apparatus according to this embodiment having the above-described configuration, the raw material powder is sprayed toward the seed substrate by the spraying means in the film forming step to deposit the powder on the surface of the seed substrate. Then, a film is formed, and the film formed on the surface of the seed substrate in the heating step is heated by the heating means to produce a single crystal from the raw material powder.

At this time, as described above, in the single crystal manufacturing apparatus according to the prior art in which energy (for example, infrared rays, laser light, etc.) serving as a heat source in the heating step is irradiated from the side where the injection means is disposed, Inside the film formed on the surface of the substrate, in addition to a temperature gradient that becomes lower as it gets closer to the seed substrate, it is injected from the injection means into a space that becomes a path for the energy that becomes the heat source to reach the powder. Since the applied powder is full, it is difficult for the energy serving as the heat source to reach the powder effectively, for example, by scattering the energy serving as the heat source. As a result, it is difficult to incorporate the film into the single crystal of the seed substrate and to effectively solid-phase grow the single crystal.

However, in the single crystal manufacturing apparatus according to the present embodiment, as described above, the spraying unit and the heating unit are arranged to face each other with the seed substrate interposed therebetween. Thereby, in the single crystal manufacturing apparatus according to the present embodiment, energy (for example, infrared rays, various laser beams, high-frequency electromagnetic waves, etc.) serving as a heat source is prevented from being scattered by the powder filling in the route to the film. In addition, the film can be heated from the contact portion side between the film and the seed substrate. As a result, in the single crystal manufacturing apparatus according to the present embodiment, energy that becomes a heat source can be effectively reached the film, and a temperature gradient that becomes higher as the seed substrate is approached is formed on the surface of the seed substrate. Since it can be generated inside the formed film, a high-quality single crystal can be efficiently solid-phase grown. In addition, for example, when the heating means and the injection means are not completely independent and the amount of powder injected from the injection means is extremely large, etc., the powder enters the vicinity of the heating means and becomes an energy that becomes a heat source. There is a possibility that (for example, infrared rays, various laser beams, high-frequency electromagnetic waves, etc.) are scattered by the powder in the path to reach the film. Moreover, when powder adheres to heating means, such as an infrared lamp, a failure may occur in the heating means. In such a case, the periphery of the injection unit and the route of reaching the film from the heating unit may be shielded by, for example, a porous filter. In this case, the porosity and the pore diameter of the porous filter are not particularly limited, but those that allow the carrier gas to permeate while suppressing the dispersion of the powder may be selected. Also, the material of the porous filter is not particularly limited, but when the porous filter is installed near the heat source, it is necessary to apply a material having heat resistance.

Incidentally, as described above, in the method for producing a single crystal according to the prior art, the production of the film and the heating of the film are generally performed by separate apparatuses. Therefore, in the single crystal manufacturing method according to the prior art, the manufacturing process and the manufacturing means of the single crystal become complicated, and there is a possibility of causing problems such as an increase in manufacturing cost. However, in the single crystal manufacturing apparatus according to this embodiment, as described above, the production of the film and the heating of the film can be performed by the same apparatus. As a result, according to the single crystal manufacturing apparatus according to the present embodiment, it is possible to avoid the complexity of the manufacturing process and manufacturing means of the single crystal, and to reduce problems such as an increase in manufacturing cost, for example.

The heating means provided in the single crystal manufacturing apparatus according to the present invention can heat the film under the conditions necessary for solid-phase growth of the single crystal from the film formed on the surface of the seed substrate. As long as it is, it is not particularly limited. However, as will be described in detail later, in order to more reliably and easily suppress the generation of pores in the process of obtaining a single crystal in the heating step and to efficiently solid-phase a good quality single crystal, for example, film formation When the step and the heating step are sequentially performed, it is desirable to employ a heating means that can realize a high temperature increase rate (that is, has a high heating efficiency). Also from this viewpoint, as the heating means provided in the single crystal manufacturing apparatus according to the present invention, as described above, for example, an infrared lamp (for example, a near infrared lamp), various lasers (for example, a CO ₂ laser, a YAG laser, Excimer laser, semiconductor laser, etc.), high-frequency heating device, and the like.

Accordingly, the second embodiment of the present invention provides:
A single crystal manufacturing apparatus according to the first embodiment of the present invention,
The heating means is a heating means for heating the film using any heat source selected from the group consisting of an infrared lamp, a laser, and a high-frequency heating device;
Is a single crystal manufacturing apparatus.

As described above, in the single crystal manufacturing apparatus according to this embodiment, the heating unit heats the film using any one of heat sources selected from the group consisting of an infrared lamp, a laser, and a high-frequency heating apparatus. It is a heating means. As a result, according to the single crystal manufacturing apparatus according to the present embodiment, in the heating step, the film is formed under conditions suitable for solid-phase growth of a good quality single crystal from the film formed on the surface of the seed substrate. Can be heated.

By the way, the film to be single-crystallized by the single-crystal manufacturing apparatus according to this embodiment does not necessarily efficiently absorb the energy supplied from the above-described heat source and convert it into heat, thereby efficiently increasing the temperature. It is not necessarily a material that can be used. In other words, it is assumed that the film to be single-crystallized by the single-crystal manufacturing apparatus according to this embodiment is a material that cannot efficiently absorb the energy supplied from the heat source described above and convert it into heat. Is done.

When a single crystal manufacturing apparatus according to this embodiment is used to crystallize such a film, a member that can efficiently absorb the energy supplied from the above-described heat source and convert it into heat (hereinafter “heat generation”). The heating step can be performed using a “member” in some cases. Specifically, in the single crystal manufacturing apparatus according to this embodiment, heat generated by efficiently absorbing energy supplied from the above-described heat source and converting it to heat on the side opposite to the side on which the seed substrate film is formed. A member is disposed, and a film formed on the surface of the seed substrate is heated by thermal energy generated from the heat generating member, so that a single crystal can be solid-phase grown from the film.

That is, the third embodiment of the present invention
A single crystal manufacturing apparatus according to the second embodiment of the present invention,
A heat generating member that absorbs the energy and generates heat; and the heat generating member is disposed on the opposite side of the seed substrate from the side on which the film is formed.
Is a single crystal manufacturing apparatus.

As described above, in the single crystal manufacturing apparatus according to this embodiment, the heat generating member that absorbs the energy and generates heat is disposed on the opposite side of the seed substrate from the side on which the film is formed. Thereby, in the single crystal manufacturing apparatus according to the present embodiment, the film to be single crystallized by the single crystal manufacturing apparatus according to the present embodiment efficiently absorbs the energy supplied from the heat source and converts it into heat. Even in the case of a material that cannot be done, the heating member arranged on the side opposite to the side on which the seed substrate film is formed efficiently absorbs the energy supplied from the heat source described above and converts it into heat, The film formed on the surface of the seed substrate can be heated by the heat generated from the heat generating member via the seed substrate, and a single crystal can be solid-phase grown from the film.

By the way, as the material constituting the heat generating member, for example, the energy supplied from the heat source described above can be efficiently absorbed and converted into heat, and the heat energy generated from the heat generating member passes through the seed substrate. Thus, a material that can be uniformly and efficiently transmitted to a film formed on the surface of the seed substrate is desirable. Examples of such materials include metals and ceramics having high thermal conductivity.

That is, the fourth embodiment of the present invention is
A single crystal manufacturing apparatus according to the third embodiment of the present invention,
The heat generating member comprises metal or ceramics;
Is a single crystal manufacturing apparatus.

As described above, the heat generating member included in the single crystal manufacturing apparatus according to this embodiment includes metal or ceramics. Specific examples of the metal suitable as the material included in the heat generating member include refractory metals such as platinum, niobium, tungsten, and molybdenum. Specific examples of ceramics suitable as a material included in the heat generating member include alumina, aluminum nitride, silicon carbide, and silicon nitride. Since the heat generating member is in direct contact with the seed substrate, it is necessary that the heat generating member has no reactivity with the seed substrate, and it is desirable to use a member that can withstand a desired heat treatment temperature and has high thermal conductivity. More preferably, it is further desirable to use a heat generating member having a thermal expansion coefficient close to that of the seed substrate.

By the way, as described at the beginning of the present specification, the present invention is not only related to a single crystal manufacturing apparatus capable of manufacturing a homogeneous single crystal with few pores with high productivity. It also relates to the single crystal production method used.

Accordingly, the fifth embodiment of the present invention provides:
Using the single crystal manufacturing apparatus according to any one of the first to fourth embodiments of the present invention, the film forming step and the heating step are sequentially performed, so that the single crystal is formed from the powder. Is a method for producing a single crystal.

As is clear from the description of the various embodiments as the single crystal manufacturing apparatus described above, according to the single crystal manufacturing method according to the present embodiment, a homogeneous single crystal with few pores can be manufactured with high productivity. Can do.

By the way, in the film forming step included in the single crystal manufacturing method according to the present invention, the raw material powder is deposited on the surface of the seed substrate, and the film forming method has good adhesion to the seed substrate and There is no particular limitation as long as it is possible to form a dense film on the seed substrate that does not generate pores (micron order (that is, a size of 1 μm or more)) in the film. However, as described above, the single crystal manufacturing apparatus according to the present invention is an injection unit that forms a film by spraying raw material powder toward a seed substrate to deposit the powder on the surface of the seed substrate. Is provided. Therefore, in the film forming step included in the method for producing a single crystal according to the present invention, the raw material powder is deposited on the surface of the seed substrate to form a film. It is desirable that the powder is deposited on the surface of the seed substrate by spraying toward the seed substrate. Specific examples of such a method include an aerosol deposition method (AD method) and a powder jet deposition method (PJD method).

Accordingly, the sixth embodiment of the present invention provides:
A method for producing a single crystal according to the fifth embodiment of the present invention, comprising:
The method for forming the film on the surface of the seed substrate in the film forming step is any method selected from the group consisting of an aerosol deposition method (AD method) and a powder jet deposition method (PJD method). thing,
Is a method for producing a single crystal.

As described above, in the method for producing a single crystal according to the present embodiment, an aerosol deposition method (AD method) or a powder jet deposition is used as a method for forming the film on the surface of the seed substrate in the film forming step. Any of the methods (PJD method) is adopted. As a result, according to the method for producing a single crystal according to this embodiment, a dense film having good adhesion to the seed substrate and having no pores (on the order of microns) in the film is reliably formed on the seed substrate. Can be formed. The details of each of the aerosol deposition method (AD method) and the powder jet deposition method (PJD method) are well known to those skilled in the art, and thus the description thereof is omitted in this specification.

By the way, in the solid-phase growth of a single crystal, the contact portion between the film and the seed substrate is heated, and a temperature gradient is generated in the film so that the temperature becomes higher as it approaches the seed substrate. It is desirable to incorporate it into a single crystal for solid phase growth. That is, in the heating step included in the single crystal manufacturing method according to the present invention, it is desirable to heat the film from the seed substrate side.

That is, the seventh embodiment of the present invention is
A method for producing a single crystal according to the sixth embodiment of the present invention, comprising:
The film is heated from the seed substrate side in the heating step;
Is a method for producing a single crystal.

As described above, in the single crystal manufacturing method according to this embodiment, the film is heated from the seed substrate side in the heating step. Thereby, in the single crystal manufacturing method according to the present embodiment, a temperature gradient is generated in the film so as to become a high temperature as it approaches the seed substrate. As a result, according to the method for producing a single crystal according to this embodiment, a high-quality single crystal with few pores can be produced with high productivity even in a material system in which it is difficult to obtain a raw material melt.

By the way, as a result of intensive studies, the present inventors have heated a film formed on the surface of the seed substrate so as to have a thickness of a predetermined value or less from the seed substrate side at a heating rate of a predetermined value or more. The inventors have found that a high-quality single crystal with few pores can be produced with high productivity. Such knowledge can also be applied to the single crystal manufacturing method according to the present embodiment.

That is, the eighth embodiment of the present invention is
A method for producing a single crystal according to the seventh embodiment of the present invention, comprising:
The film formed on the surface of the seed substrate in the film forming step has a thickness that is 100 μm or less in a direction perpendicular to the surface of the seed substrate, and the temperature of the film is increased in the heating step The speed is 30 ° C./min or more,
Is a method for producing a single crystal.

As described above, in the single crystal manufacturing method according to this embodiment, the film thickness that is the thickness in the direction perpendicular to the surface of the seed substrate of the film formed on the surface of the seed substrate in the film formation step. Is 100 μm or less, and the temperature rising rate of the film in the heating step is 30 ° C./min or more. Thereby, in the single crystal manufacturing method according to this embodiment, a high-quality single crystal with few pores can be produced with high productivity even in a material system in which it is difficult to obtain a raw material melt.

It should be noted that a detailed mechanism for obtaining a high-quality single crystal with few pores by heating a film having a thickness of a predetermined value or less as described above at a heating rate of a predetermined value or more has not yet been elucidated. However, by heating a film having a thickness below a predetermined value as described above at a rate of temperature increase above a predetermined value, an appropriate temperature gradient is generated inside the film, while suppressing grain growth in the film. It is considered that the generation of pores is suppressed because solid-phase growth proceeds sequentially from the interface between the film and the seed substrate.

In addition, as a heating means which can heat the film | membrane formed on the surface of a seed substrate as mentioned above from the seed substrate side, common stage heaters, such as a ceramic heater, can also be mentioned, for example. However, with such a stage heater, for example, it is difficult to realize a temperature increase rate defined in the single crystal manufacturing method according to the present embodiment. Also from this viewpoint, as described above, as the heating means provided in the single crystal manufacturing apparatus according to the present invention, for example, an infrared lamp (for example, a near infrared lamp), various lasers (for example, a CO ₂ laser, a YAG laser, Excimer laser, semiconductor laser, etc.) and a high-frequency heating device are desirable.

In addition, the film thickness (which is the thickness in a direction perpendicular to the surface of the seed substrate) formed on the surface of the seed substrate in the film forming step included in the method for manufacturing a single crystal according to this embodiment is 100 μm or less. It is desirable that the thickness is 30 μm or less. In addition, the temperature rising rate of the film in the heating step included in the method for producing a single crystal according to this embodiment is desirably 30 ° C./min or more, and more desirably 300 ° C./min or more.

Accordingly, the ninth embodiment of the present invention provides:
A method for producing a single crystal according to the eighth embodiment of the present invention, comprising:
A film thickness of the film formed on the surface of the seed substrate in the film forming step is 30 μm or less;
Is a method for producing a single crystal.

The tenth embodiment of the present invention is
A method for producing a single crystal according to any one of the eighth or ninth embodiments of the present invention,
The heating rate of the film in the heating step is 300 ° C./min or more,
Is a method for producing a single crystal.

By the way, in general, when an attempt is made to produce a single crystal mainly composed of oxide or nitride (for example, zinc oxide (ZnO), gallium nitride (GaN), etc.), if excessive thermal energy is given in the heating step, Due to decomposition and sublimation of the material, composition deviation and pores are likely to occur in the obtained crystal film. On the other hand, the single crystal manufacturing method according to the present invention that sequentially executes the film forming step and the heating step is performed by heating a film having a thickness of a predetermined value or less at a temperature rising rate of a predetermined value or more as described above. By generating an appropriate temperature gradient inside the film, it is possible to suppress the generation of pores in the obtained single crystal. That is, the single crystal manufacturing method according to the present invention, in which the film forming step and the heating step are sequentially performed, is particularly preferably applied when trying to obtain a single crystal mainly composed of oxide or nitride. Can do.

Accordingly, the eleventh embodiment of the present invention is
A method for producing a single crystal according to any one of the fifth to tenth embodiments of the present invention,
The main component of the film is any one material selected from the group consisting of oxides and nitrides;
Is a method for producing a single crystal.

Note that specific examples of oxides and nitrides that can be used as the main components of the film formed on the surface of the seed substrate in the method for producing a single crystal according to this embodiment include zinc oxide (ZnO) and nitridation, respectively. An example is gallium (GaN).

Thus, the twelfth embodiment of the present invention is
A method for producing a single crystal according to the eleventh embodiment of the present invention, comprising:
The oxide is zinc oxide (ZnO) and the nitride is gallium nitride (GaN);
Is a method for producing a single crystal.

As described above, for example, when a material with high sublimation properties such as zinc oxide (ZnO) and gallium nitride (GaN) is used as the main component of the film, the material is sublimated in the heating step, resulting in the result. It is desirable to suppress the occurrence of problems such as compositional deviation or pore formation in the single crystal. As a measure for achieving this object, for example, an upper limit is set for the maximum temperature reached in the heating step, or an upper limit is set for the holding time at the maximum temperature. However, in this case, it is necessary to set these upper limits with due consideration of the melting point of the substance used as the main component of the film, the thickness of the film, and the like.

Incidentally, the single crystal manufacturing method according to the present invention is a method for manufacturing a single crystal by an epitaxial growth method, and the main component of the single crystal and the main component of the seed substrate manufactured by the single crystal manufacturing method are the same. Or it may be different. In other words, the single crystal manufacturing method according to the present invention may be a homoepitaxial growth method or a heteroepitaxial growth method.

When the single crystal manufacturing method according to the present invention is a homoepitaxial growth method, the main component of the single crystal and the main component of the seed substrate produced by the single crystal manufacturing method are the same. In this case, for example, if the main component of the film formed on the surface of the seed substrate is zinc oxide (ZnO) or gallium nitride (GaN), the main component of the seed substrate is also zinc oxide (ZnO) or Gallium nitride (GaN). On the other hand, when the single crystal manufacturing method according to the present invention is a heteroepitaxial growth method, the main component of the single crystal manufactured by the single crystal manufacturing method is different from the main component of the seed substrate. In this case, for example, even if the main component of the film formed on the surface of the seed substrate is zinc oxide (ZnO) or gallium nitride (GaN), the main component of the seed substrate is not zinc oxide (ZnO), respectively. It is a substance that is not a substance or gallium nitride (GaN). A specific example of a substance that can be used as a main component of the seed substrate and is not zinc oxide (ZnO) or gallium nitride (GaN) is sapphire, for example.

Accordingly, the thirteenth embodiment of the present invention provides:
A method for producing a single crystal according to any one of the fifth to twelfth embodiments of the present invention,
The main component of the seed substrate is any one material selected from the group consisting of zinc oxide (ZnO), gallium nitride (GaN), and sapphire,
Is a method for producing a single crystal.

As described above, in the single crystal manufacturing method according to the present embodiment, any one material selected from the group consisting of zinc oxide (ZnO), gallium nitride (GaN), and sapphire is the main component of the seed substrate. It is. Therefore, when the main component of the film formed on the surface of the seed substrate and the main component of the seed substrate are both zinc oxide (ZnO) or gallium nitride (GaN), the single crystal manufacturing according to this embodiment is performed. The method is a homoepitaxial growth method. On the other hand, when the combination of the main component of the film formed on the surface of the seed substrate and the main component of the seed substrate is other than the above, the single crystal manufacturing method according to this embodiment is a heteroepitaxial growth method.

Further, in the method for producing a single crystal according to the present invention, the film formed on the seed substrate is not limited to the above-mentioned various main components as long as it does not adversely affect the properties of the resulting single crystal. (Dopant) may be contained. Specifically, as a component constituting the film, for example, zinc oxide (ZnO), aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P), Arsenic (As), Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Carbon (C), Sulfur (S), Silicon (Si), Lithium (Li), Sodium (Na), At least one element selected from the group consisting of potassium (K), magnesium (Mg), cadmium (Cd), selenium (Se), tellurium (Te), silver (Ag), and copper (Cu). A doped material or the like may be used.

That is, the fourteenth embodiment of the present invention is
A method for producing a single crystal according to any one of the fifth to thirteenth embodiments of the present invention,
The film is made of aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P), arsenic (As), fluorine (F), chlorine (Cl), bromine. (Br), iodine (I), carbon (C), sulfur (S), silicon (Si), lithium (Li), sodium (Na), potassium (K), magnesium (Mg), cadmium (Cd), selenium Containing at least one element selected from the group consisting of (Se), tellurium (Te), silver (Ag), and copper (Cu) as an impurity;
Is a method for producing a single crystal.

As described above, in the single crystal manufacturing method according to this embodiment, the film is made of aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P). Arsenic (As), Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Carbon (C), Sulfur (S), Silicon (Si), Lithium (Li), Sodium (Na) , Potassium (K), magnesium (Mg), cadmium (Cd), selenium (Se), tellurium (Te), silver (Ag), and at least one element selected from the group consisting of copper (Cu) As an impurity. Thereby, in the single crystal manufacturing method according to the present embodiment, for example, the conductivity of the resulting single crystal can be adjusted to a desired level. In the single crystal manufacturing method according to the present embodiment, when a substance containing aluminum (Al) or gallium (Ga) is used as the main component of the film formed on the surface of the seed substrate, aluminum (Al It goes without saying that gallium (Ga) cannot be contained as an impurity (dopant).

By the way, in the single crystal manufacturing method according to the present invention, as described above, the raw material powder is sprayed toward the seed substrate, and the powder is deposited on the surface of the seed substrate to form a film. And a heating means for heating the film formed on the surface of the seed substrate, wherein the powder is sprayed toward the seed substrate by the spraying means. A single crystal is produced from the powder by executing a film forming step for forming the film thereon and a heating step for heating the film formed on the surface of the seed substrate by the heating means. At this time, in the single crystal manufacturing method according to the present invention, a single crystal is produced from the raw material powder by executing the film forming step and then the heating step, as in the conventional single crystal manufacturing method. can do.

However, in the single crystal manufacturing apparatus according to the present invention, as described above, the production of the film (deposition step) and the heating of the film (heating step) can be performed by the same apparatus. In addition, in the single crystal manufacturing apparatus according to the present embodiment, as described above, the spraying means and the heating means are arranged so as to face each other with the seed substrate interposed therebetween. Therefore, in the single crystal manufacturing method according to the present invention using such a single crystal manufacturing apparatus, the heating step can be performed while the film forming step is performed.

That is, the fifteenth embodiment of the present invention is
By using the single crystal manufacturing apparatus according to any one of the first to fourth embodiments of the present invention, the film forming step and the heating step are performed in parallel, so that the single crystal is formed from the powder. Is a method for producing a single crystal.

As described above, in the single crystal manufacturing method according to this embodiment, the film forming step and the heating step are executed in parallel. That is, in the single crystal manufacturing method according to this embodiment, the heating step is performed while the film forming step is performed. Therefore, according to the single crystal manufacturing method according to the present embodiment, higher productivity can be achieved.

In the single crystal manufacturing method according to this embodiment, a film can be formed while the heating temperature by the heating means is kept constant, so that a stage heater or the like having a slow temperature rise rate can be used. However, even when the film is formed while the heating temperature by the heating means is kept constant, it is necessary to generate a temperature gradient in the collision particles when the particles collide with the seed substrate by jetting. Therefore, a method of heating the entire atmosphere uniformly is not desirable.

By the way, in the film forming step included in the method for producing a single crystal according to the present embodiment, the raw material powder is deposited on the surface of the seed substrate to form a film. It is desirable that the powder is deposited on the surface of the seed substrate by spraying a body toward the seed substrate. Specific examples of such a method include an aerosol deposition method (AD method) and a powder jet deposition method (PJD method).

Accordingly, the sixteenth embodiment of the present invention provides:
A method for producing a single crystal according to the fifteenth embodiment of the present invention, comprising:
The method for forming the film on the surface of the seed substrate in the film forming step is any method selected from the group consisting of an aerosol deposition method (AD method) and a powder jet deposition method (PJD method). thing,
Is a method for producing a single crystal.

Also in the single crystal manufacturing method according to the present embodiment, in solid phase growth of a single crystal, solid phase growth may occur simultaneously with film formation, but the solid phase growth rate may be slower than the film formation rate. . In the latter case (that is, when the solid-phase growth rate is slower than the film formation rate), the contact portion between the film and the seed substrate is heated as in the case of sequentially performing the film formation step and the heating step, It is desirable to cause the film to be incorporated into the single crystal of the seed substrate for solid-phase growth by generating a temperature gradient in the film that increases in temperature as it approaches the seed substrate. That is, also in the single crystal manufacturing method according to this embodiment, it is desirable to heat the film from the seed substrate side.

Accordingly, the seventeenth embodiment of the present invention provides:
A method for producing a single crystal according to the sixteenth embodiment of the present invention, comprising:
The film is heated from the seed substrate side in the heating step;
Is a method for producing a single crystal.

By the way, as described above, when a single crystal mainly composed of an oxide or nitride (for example, zinc oxide (ZnO), gallium nitride (GaN), etc.) is generally formed, excessive thermal energy is used in the heating step. , Compositional deviation and pores are likely to occur in the obtained crystal film due to decomposition and sublimation of the material. On the other hand, in the single crystal manufacturing method according to the present invention in which the film forming step and the heating step are performed in parallel, generation of pores in the single crystal obtained by generating an appropriate temperature gradient inside the film as described above. Can be suppressed. That is, the single crystal manufacturing method according to the present invention in which the film forming step and the heating step are performed in parallel is also preferably applied to obtain a single crystal mainly composed of oxide or nitride. Can do.

Accordingly, the eighteenth embodiment of the present invention provides:
A method for producing a single crystal according to any one of the fifteenth to seventeenth embodiments of the present invention,
The main component of the film is any one material selected from the group consisting of oxides and nitrides;
Is a method for producing a single crystal.

Further, specific examples of oxides and nitrides that can be used as the main components of the film formed on the surface of the seed substrate in the single crystal manufacturing method according to this embodiment include zinc oxide (ZnO) and nitridation, respectively. An example is gallium (GaN).

Accordingly, the nineteenth embodiment of the present invention provides:
A method for producing a single crystal according to the eighteenth embodiment of the present invention, comprising:
The oxide is zinc oxide (ZnO) and the nitride is gallium nitride (GaN);
Is a method for producing a single crystal.

By the way, also in the single crystal manufacturing method according to the present invention in which the film forming step and the heating step are executed in parallel, the main component of the single crystal and the main component of the seed substrate manufactured by the method are the same. Or it may be different. In other words, the single crystal manufacturing method according to the present invention in which the film forming step and the heating step are performed in parallel may also be a homoepitaxial growth method or a heteroepitaxial growth method. That is, the main component of the seed substrate used in the single crystal manufacturing method according to the present invention in which the film forming step and the heating step are performed in parallel also relates to the present invention in which the film forming step and the heating step are sequentially performed. Similar to the main component of the seed substrate used in the single crystal manufacturing method, it can be selected from the group consisting of zinc oxide (ZnO), gallium nitride (GaN), and sapphire.

Accordingly, the twentieth embodiment of the present invention provides:
A method for producing a single crystal according to any one of the fifteenth to nineteenth embodiments of the present invention,
The main component of the seed substrate is any one material selected from the group consisting of zinc oxide (ZnO), gallium nitride (GaN), and sapphire,
Is a method for producing a single crystal.

In the single crystal manufacturing method according to the present invention in which the film formation step and the heating step are performed in parallel, the film formed on the seed substrate also has no adverse effect on the properties of the resulting single crystal. In addition to the above-mentioned various main components, an impurity (dopant) may be contained. Specifically, as a component constituting the film, for example, zinc oxide (ZnO), aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P), Arsenic (As), Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Carbon (C), Sulfur (S), Silicon (Si), Lithium (Li), Sodium (Na), At least one element selected from the group consisting of potassium (K), magnesium (Mg), cadmium (Cd), selenium (Se), tellurium (Te), silver (Ag), and copper (Cu). A doped material or the like may be used.

That is, the twenty-first embodiment of the present invention
A method for producing a single crystal according to any one of the fifteenth to twentieth embodiments of the present invention,
The film is made of aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P), arsenic (As), fluorine (F), chlorine (Cl), bromine. (Br), iodine (I), carbon (C), silicon (Si), sulfur (S), lithium (Li), sodium (Na), potassium (K), magnesium (Mg), cadmium (Cd), selenium Containing at least one element selected from the group consisting of (Se), tellurium (Te), silver (Ag), and copper (Cu) as an impurity;
Is a method for producing a single crystal.

By the way, in the method of sequentially performing the film forming step and the heating step among the single crystal manufacturing methods according to various embodiments of the present invention, in the film forming step of forming a film on the surface of the seed substrate, the seed In the heating step of forming a film having a thickness of 100 μm or less in a direction perpendicular to the surface of the substrate, and then heating the film formed on the surface of the seed substrate to obtain a single crystal, A high-quality single crystal having few pores even in a material system in which it is difficult to obtain a raw material melt by heating the film from the seed substrate side and raising the temperature at a temperature rising rate of 30 ° C./min or more. Can be produced with high productivity.

That is, in the method of sequentially performing the film forming step and the heating step among the single crystal manufacturing methods according to various embodiments of the present invention, when the method is executed for only one cycle, the thickness of the obtained single crystal is Generally, it is 100 μm or less, more preferably 30 μm or less. Therefore, for example, when a single crystal having a larger thickness such as a single crystal wafer is to be manufactured, it is necessary to repeatedly execute the single crystal manufacturing method over a plurality of cycles. Moreover, even in the method of performing the film forming step and the heating step in parallel in the single crystal manufacturing method according to the present invention, it may be difficult to manufacture a single crystal having a desired large thickness. Even in such a case, it is necessary to repeatedly execute the single crystal manufacturing method according to the present invention over a plurality of cycles.

Accordingly, the twenty-second embodiment of the present invention provides:
Obtaining a single crystal by repeatedly executing the method for producing a single crystal according to any one of the fifth to twenty-first embodiments of the present invention,
Is a method for producing a single crystal.

As described above, according to the single crystal manufacturing method according to the present embodiment, the single crystal manufacturing method according to the present invention including the various embodiments described so far is repeatedly executed over a plurality of cycles. A single crystal having a desired thickness can be obtained.

Incidentally, as described above, the present invention also relates to a single crystal manufactured by the single crystal manufacturing method according to the present invention. In addition, the main component of the substance for obtaining a single crystal by the single crystal manufacturing method according to the present embodiment is not particularly limited. For example, various ceramics, oxides such as zinc oxide (ZnO), gallium nitride (GaN), and the like And nitrides thereof. Among these, it is desirable to apply the single crystal manufacturing method according to the present invention to single crystallization of zinc oxide (ZnO) and gallium nitride (GaN), and in particular to the single crystallization of zinc oxide (ZnO), the present invention. It is desirable to apply the single crystal manufacturing method according to the above.

That is, the twenty-third embodiment of the present invention is
Obtained by the single crystal manufacturing method according to the fifth to twenty-second embodiments of the present invention,
A zinc oxide (ZnO) single crystal characterized by

Further, as described above, in the single crystal manufacturing method according to the present invention, when only one cycle of the method of sequentially performing the film forming step and the heating step is performed, the thickness of the obtained single crystal film is generally 100 μm. Hereinafter, more preferably 30 μm or less. Even in a method in which the film forming step and the heating step are performed in parallel, it may be difficult to produce a single crystal having a desired large thickness. However, depending on the application, a single crystal having a thickness exceeding 30 μm may be desirable.

Accordingly, the twenty-fourth embodiment of the present invention provides:
A zinc oxide (ZnO) single crystal according to the twenty-third embodiment of the present invention,
A crystal thickness that is a thickness of the crystal in a direction orthogonal to the surface of the seed substrate of the film formed in the film forming step exceeds 30 μm;
A zinc oxide (ZnO) single crystal characterized by

Furthermore, depending on the application, a single crystal having a thickness exceeding 100 μm may be desirable. However, as described above, in the single crystal manufacturing method according to the present invention, when the method of sequentially executing the film forming step and the heating step is executed for only one cycle, the thickness of the obtained single crystal film is generally 100 μm. It becomes as follows. Even in a method in which the film forming step and the heating step are performed in parallel, it may be difficult to produce a single crystal having a desired large thickness. Therefore, for example, when a single crystal having a larger thickness such as a single crystal wafer is to be manufactured, it is necessary to repeatedly execute the single crystal manufacturing method according to the present invention over a plurality of cycles.

That is, the twenty-fifth embodiment of the present invention is
A zinc oxide (ZnO) single crystal according to the twenty-fourth embodiment of the present invention,
It is obtained by the single crystal manufacturing method according to claim 22, and a crystal thickness that is a thickness of the crystal in a direction orthogonal to a surface of the seed substrate of the film formed in the film forming step exceeds 100 μm. ,
A zinc oxide (ZnO) single crystal characterized by

Further, as described above, in the method for producing a single crystal according to the present invention, the film formed on the surface of the seed substrate does not adversely affect the characteristics of the resulting single crystal. In addition to the main components, impurities (dopants) may be contained. Specifically, as a component constituting the film, for example, aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P), arsenic (As), fluorine (F), chlorine (Cl), bromine (Br), iodine (I), carbon (C), silicon (Si), sulfur (S), lithium (Li), sodium (Na), potassium (K), magnesium (Mg), cadmium (Cd), selenium (Se), tellurium (Te), silver (Ag), at least one element selected from the group consisting of copper (Cu), zinc oxide (ZnO), etc. A material doped with the main component may be used. By containing these dopants, for example, desired characteristics such as n-type conversion, p-type conversion, or band gap control can be imparted to the single crystal.

Among these, aluminum (Al), gallium (Ga), indium (In), boron (B), fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and n-type dopants Silicon (Si) is desirable, and aluminum (Al), gallium (Ga), and indium (In) are particularly desirable. The content of these impurities (dopants) is preferably 0.02 at% or more, more preferably 0.1 at% or more. When the content of these impurities (dopants) is less than 0.02 at%, it is difficult to obtain the desired desired characteristics such as high conductivity (low electrical resistance), for example. Absent.

Accordingly, the twenty-sixth embodiment of the present invention provides:
A zinc oxide (ZnO) single crystal according to any one of the twenty-third to twenty-fifth embodiments of the present invention,
Containing at least one element selected from the group consisting of aluminum (Al), gallium (Ga), and indium (In) as impurities, and the impurity content is 0.02 at% or more. ,
A zinc oxide (ZnO) single crystal characterized by

The twenty-seventh embodiment of the present invention provides
A zinc oxide (ZnO) single crystal according to the twenty-sixth embodiment of the present invention,
The impurity content is 0.1 at% or more,
A zinc oxide (ZnO) single crystal characterized by

By the way, as described above, examples of the characteristics that can be achieved by adding an n-type dopant to the main component constituting the single crystal according to the present invention include high conductivity (low electrical resistance) and the like. Can do. In this case, for example, when a zinc oxide single crystal is used as a substrate of an electronic device using a pn junction such as an LED, the result is obtained when the single crystal itself is used as an electrode (cathode) on the n-type layer side. The resistivity of the obtained single crystal is desirably 1 × 10 ⁻³ Ω · cm or less. Thus, by using a conductive zinc oxide single crystal as a base material, not only a cathode is unnecessary, but also a vertical structure can be realized in a light emitting element such as an LED.

That is, the twenty-eighth embodiment of the present invention is
A zinc oxide (ZnO) single crystal according to any one of the twenty-third to twenty-seventh embodiments of the present invention,
Resistivity is 1 × 10 ⁻³ Ω · cm or less,
A zinc oxide (ZnO) single crystal characterized by

Hereinafter, the configuration of a single crystal manufacturing apparatus and a single crystal manufacturing method using the apparatus according to some embodiments of the present invention will be described in more detail. However, the following description is for illustrative purposes only, and the scope of the present invention should not be construed as being limited to the following description.

<Configuration of single crystal manufacturing equipment>
FIG. 1 is an example of a schematic configuration diagram showing an outline of the configuration of the single crystal manufacturing apparatus 20 according to one embodiment of the present invention as described above. As shown in FIG. 1, the single crystal manufacturing apparatus 20 according to the present embodiment injects powder (raw material powder) containing raw material components onto the surface of the seed substrate 21 in an atmosphere at atmospheric pressure lower than atmospheric pressure. It is configured as an apparatus used in an aerosol deposition method (AD method) for depositing and forming a film. The single crystal manufacturing apparatus 20 includes an aerosol generation unit 22 that generates an aerosol of raw material powder, and a crystal generation that injects the raw material powder onto the seed substrate 21 to form a film containing the raw material component, and single crystallization of the film The unit 30 includes a heating light source (heating means) 40 for heating the film formed on the seed substrate 21 with irradiation heat, and a thermocouple 35 for measuring the temperature of the seed substrate 21.

The aerosol generation unit 22 accommodates the raw material powder 11 and supplies the generated aerosol to the crystal generation unit 30 by the aerosol generation chamber 23 that generates the aerosol by the carrier gases 12 and 13 that are supplied from a gas cylinder (not shown). The raw material supply pipe 24 is provided. The crystal generation unit 30 includes a seed substrate 21, a film formation chamber 31 that sprays aerosol on the seed substrate 21 under reduced pressure conditions, and a substrate installation that is disposed inside the film formation chamber 31 and fixes the seed substrate 21. A stage 34 and an XY stage 33 that moves the substrate installation stage 34 in the X-axis-Y-axis directions are provided. The crystal generation unit 30 includes an injection nozzle (injection means) 36 that injects aerosol onto the seed substrate 21 through a rectangular slit 37 formed at the tip, a vacuum pump 38 that decompresses the film formation chamber 31, It has.

The substrate placement stage 34 and the XY stage 33 are hollow, and a heating light source 40 is disposed therein. Light (for example, infrared light) from the heating light source 40 is irradiated to the heat generating member 32 installed on the lower side of the seed substrate 21 (that is, the side opposite to the film), and the heat generating member 32 generates heat. The film can be heated from the back surface of the seed substrate 21. As described above, the heat source for heating the film is not particularly limited. For example, in addition to various lasers such as an infrared lamp, a CO ₂ laser, a YAG laser, an excimer laser, and a semiconductor laser, a high-frequency heating device is used. Etc. may be used. Further, when the seed substrate can be directly heated by these heating sources, the heat generating member 32 may not be provided.

In the single crystal manufacturing apparatus 20 according to the present embodiment, after the raw material powder is deposited on the surface of the seed substrate 21 to form a film, a heating step for performing single crystallization may be sequentially performed. Alternatively, a film formation step and a heating step (single crystal) are performed by spraying aerosol onto the seed substrate 21 while heating the seed substrate 21 from the back surface with light from the heating light source 40 to form a film on the surface of the seed substrate 21. May be performed simultaneously in parallel.

1. Preparation of Samples for Various Evaluations (1) Materials for Film and Seed Substrate In this example, various evaluations were made using various raw material powders for film formation (film formation powders) and seed substrates listed in Table 1 below. A sample was prepared. In this example, a ZnO single crystal substrate (10 mm × 10 mm square, thickness 0.5 mm, c-plane) was used as a seed substrate for any of the experimental examples. In this embodiment, an embodiment in which the film forming step and the heating step are sequentially executed is adopted.

(2) Preparation of film forming raw material powder The zinc oxide (ZnO) in which aluminum (Al) is used as the film forming raw material powder (film forming powder) in Experimental Examples 01 and 02 is as follows. It was prepared as follows. First, zinc oxide (ZnO) powder (volume basis median diameter (D50) = 0.8 μm) and aluminum oxide (Al ₂ O ₃ ) powder (volume basis D50 = 0.5 μm) are converted into atomic moles of aluminum (Al). They were weighed and mixed so that the ratio was 0.2 at%. The mixed powder thus obtained was wet mixed in a pot mill.

The powder thus wet-mixed was fired in air at 1400 ° C. for 5 hours to synthesize zinc oxide (ZnO) powder in which aluminum (Al) was dissolved. The synthetic powder thus obtained was wet-ground for 5 hours in a pot mill using zirconia balls so that the volume standard D50 was 2.6 μm. The zinc oxide (ZnO) in which aluminum (Al) was dissolved in 0.2 at% obtained as described above was used as a film forming raw material powder (film forming powder) in Experimental Examples 01 and 02. .

(3) Film-forming step In this example, in any of the experimental examples, the above-mentioned various film-forming powders were deposited on the surface of each seed substrate by the AD method using the single crystal manufacturing apparatus shown in FIG. To form a film. Specifically, nitrogen (N ₂ ) gas is flowed as a carrier gas at a flow rate of 6 L / min, the pressure in the aerosol generating chamber is 50 to 70 kPa, the pressure in the film forming chamber is 0.1 kPa or less, and the film forming powder The opening size of the injection nozzle (manufactured by SUS) was 10 mm × 0.8 mm. Further, as a nozzle scanning method during film formation, scanning was performed simultaneously with film formation at the scanning distance, scanning speed, and number of scans listed in Table 1.

(4) Heating step In the heating step, the various films were heated using the single crystal manufacturing apparatus shown in FIG. A near-infrared lamp was used as a light source for light heating. Also, since the above various films have a low near-infrared absorption coefficient, a platinum plate is disposed as a heating member on the surface opposite to the surface on which the seed substrate film is formed, and the surface on which the seed substrate film is formed. The film was heated from the seed substrate side by irradiating near infrared rays from the opposite side and causing the platinum plate to absorb the near infrared rays. The atmosphere, heating temperature (surface temperature), heating rate, and holding time in the heating step are as listed in Table 1. The thickness of the single crystal film after the heating step is also listed in Table 1.

2. Evaluation Method for Various Evaluation Samples (1) Cross-sectional SEM Observation The various evaluation samples that have undergone the above heating step are polished along a surface orthogonal to the main surface of the seed substrate, and a scanning electron microscope (JSM Co., Ltd., JSM) -6390), 40 fields of view were observed from the edge of the film on the polished surface (cross section) at a magnification of 5000 times. As a result of the cross-sectional SEM observation, there are no micron-order (ie, 1 μm or more) pores, and sub-micron order (ie, less than 1 μm) pores are detected in less than 10 locations, and When the interface between the film and the seed substrate disappeared after the heating step, it was judged that a dense single crystal was successfully obtained. In addition, when the state of the film before the heating step was observed by the same method, in all the experimental examples, pores on the order of microns (that is, a size of 1 μm or more) were not observed, and the relative density measured by the Archimedes method was It was 95% or more.

(2) In-plane rocking curve (XRC) measurement A multi-functional high-resolution X-ray diffractometer (Bulker AXS Co., Ltd., D8 DISCOVER) is used for the C-plane of various evaluation samples that have undergone the above heating step. In-plane rocking curve (XRC) measurements were made using under conditions. When a (100) peak was detected, it was judged that a single crystal was obtained satisfactorily.

・ Tube voltage: 40kV
・ Tube current 40mA
・ Anti-scattering slit: 3 °
・ Step width: 0.001 °
・ Scanning speed: 0.5 seconds / step ・ Incident angle: 1 °

(3) Secondary ion mass spectrometry (D-SIMS)
For each sample for evaluation that has undergone the above heating step, a secondary ion mass spectrometer (IMS-6f, manufactured by Ametec Corporation, Kameka Division) is used under the following conditions, and impurities (dopants) in the single crystallized film: As a result, the concentration and distribution state of aluminum (Al) were evaluated. The distribution state was uniform if the Al concentration in the film was in the range of 0.1 to 0.3 at%.

・ Ion species: Cs ⁺
・ Ion energy 14.5 keV
・ Charge compensation: Platinum (Pt) coating

(4) Resistivity measurement by four-probe method A low resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Loresta-AX, Loresta four-probe PSP probe (MCP-TP06P)) ) Was used to measure resistivity by the four-probe method. Measurements were generally made in accordance with JIS K 7194. The electrode spacing was 1.5 mm, the sample area was 10 mm × 10 mm, and the measurement location was only the center of the sample. The resistivity was calculated based on the following formula (1).

In the above formula, ρ represents resistivity [Ω · cm], F represents resistivity correction coefficient, t represents film thickness [cm], and R represents resistance [Ω]. The resistivity correction coefficient F was calculated using the formula described in JIS K 7194.

3. Evaluation Results of Various Evaluation Samples The results of the evaluation methods (1) to (3) for the various evaluation samples that have undergone the heating step are also listed in Table 1. As is clear from the evaluation results shown in Table 1, in each of Experimental Examples 01 and 02, the viewpoint of suppression of pores in the film, promotion of single crystallization, and homogeneous distribution of impurities (dopant) As a result, a single crystal having extremely good quality could be obtained. Incidentally, it was confirmed that aluminum (Al) as an impurity was uniformly contained in the film in a concentration range of 0.1 to 0.3 at%, and a very low resistivity of 1 × 10 ⁻³ Ω · cm or less. A single crystal having

Although several embodiments having specific configurations have been described above for the purpose of illustrating the present invention, the scope of the present invention is not limited to these exemplary embodiments, and It goes without saying that appropriate modifications can be made within the scope of the above and the matters described in the specification.

DESCRIPTION OF SYMBOLS 11 ... Raw material powder, 12 ... Carrier gas, 13 ... Pressure adjusting gas, 20 ... Single crystal manufacturing apparatus, 21 ... Seed substrate, 22 ... Aerosol production part, 23 ... Aerosol production chamber, 24 ... Raw material supply pipe, 30 ... Crystal generating section 31 ... Film forming chamber 32 ... Susceptor (heat generating member) 33 ... XY stage 34 ... Substrate setting stage 35 ... Thermocouple 36 ... Injection nozzle (injecting means) 37: Rectangular slit 38 ... Vacuum pump and 40 ... Light source for heating (heating means).

Claims

A raw material powder is sprayed toward a seed substrate to deposit the powder on the surface of the seed substrate, and an injection means for forming a film, and the film formed on the surface of the seed substrate are heated. Heating means,
With
A film forming step of forming the film on the surface of the seed substrate by spraying the powder toward the seed substrate by the spraying means, and the film formed on the surface of the seed substrate by the heating means. A heating step to heat the membrane;
A single crystal production apparatus for producing a single crystal from the powder by executing
The spraying means and the heating means are arranged to face each other across the seed substrate;
A single crystal manufacturing apparatus characterized by the above.
The single crystal manufacturing apparatus according to claim 1,
The heating means is a heating means for heating the film using any heat source selected from the group consisting of an infrared lamp, a laser, and a high-frequency heating device;
A single crystal manufacturing apparatus characterized by the above.
The single crystal manufacturing apparatus according to claim 2,
A heat generating member that absorbs the energy and generates heat; and the heat generating member is disposed on the opposite side of the seed substrate from the side on which the film is formed.
A single crystal manufacturing apparatus characterized by the above.
The single crystal manufacturing apparatus according to claim 3,
The heat generating member comprises metal or ceramics;
A single crystal manufacturing apparatus characterized by the above.
A single crystal manufacturing method for manufacturing a single crystal from the powder by sequentially executing the film forming step and the heating step using the single crystal manufacturing apparatus according to any one of claims 1 to 4. Method.
A method for producing a single crystal according to claim 5,
The method for forming the film on the surface of the seed substrate in the film forming step is any method selected from the group consisting of an aerosol deposition method (AD method) and a powder jet deposition method (PJD method). thing,
A method for producing a single crystal.
The method for producing a single crystal according to claim 6,
The film is heated from the seed substrate side in the heating step;
A method for producing a single crystal.
A method for producing a single crystal according to claim 7,
The film formed on the surface of the seed substrate in the film forming step has a thickness that is 100 μm or less in a direction perpendicular to the surface of the seed substrate, and the temperature of the film is increased in the heating step The speed is 30 ° C./min or more,
A method for producing a single crystal.
A method for producing a single crystal according to claim 8,
A film thickness of the film formed on the surface of the seed substrate in the film forming step is 30 μm or less;
A method for producing a single crystal.
A method for producing a single crystal according to any one of claims 8 and 9,
The heating rate of the film in the heating step is 300 ° C./min or more,
A method for producing a single crystal.
A method for producing a single crystal according to any one of claims 5 to 10,
The main component of the film is any one material selected from the group consisting of oxides and nitrides;
A method for producing a single crystal.
The method for producing a single crystal according to claim 11,
The oxide is zinc oxide (ZnO) and the nitride is gallium nitride (GaN);
A method for producing a single crystal.
A method for producing a single crystal according to any one of claims 5 to 12,
The main component of the seed substrate is any one material selected from the group consisting of zinc oxide (ZnO), gallium nitride (GaN), and sapphire,
A method for producing a single crystal.
A method for producing a single crystal according to any one of claims 5 to 13,
The film is made of aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P), arsenic (As), fluorine (F), chlorine (Cl), bromine. (Br), iodine (I), carbon (C), silicon (Si), sulfur (S), lithium (Li), sodium (Na), potassium (K), magnesium (Mg), cadmium (Cd), selenium Containing at least one element selected from the group consisting of (Se), tellurium (Te), silver (Ag), and copper (Cu) as an impurity;
A method for producing a single crystal.
The single crystal manufacturing which manufactures a single crystal from the said powder by performing the said film-forming step and the said heating step in parallel using the single crystal manufacturing apparatus of any one of Claim 1 thru | or 4. Method.
The method for producing a single crystal according to claim 15,
The method for forming the film on the surface of the seed substrate in the film forming step is any method selected from the group consisting of an aerosol deposition method (AD method) and a powder jet deposition method (PJD method). thing,
A method for producing a single crystal.
The method for producing a single crystal according to claim 16,
The film is heated from the seed substrate side in the heating step;
A method for producing a single crystal.
A single crystal manufacturing method according to any one of claims 15 to 17,
The main component of the film is any one material selected from the group consisting of oxides and nitrides;
A method for producing a single crystal.
The method for producing a single crystal according to claim 18,
The oxide is zinc oxide (ZnO) and the nitride is gallium nitride (GaN);
A method for producing a single crystal.
A single crystal manufacturing method according to any one of claims 15 to 19,
The main component of the seed substrate is any one material selected from the group consisting of zinc oxide (ZnO), gallium nitride (GaN), and sapphire,
A method for producing a single crystal.
A method for producing a single crystal according to any one of claims 15 to 20,
The film is made of aluminum (Al), gallium (Ga), indium (In), nitrogen (N), boron (B), phosphorus (P), arsenic (As), fluorine (F), chlorine (Cl), bromine. (Br), iodine (I), carbon (C), silicon (Si), sulfur (S), lithium (Li), sodium (Na), potassium (K), magnesium (Mg), cadmium (Cd), selenium Containing at least one element selected from the group consisting of (Se), tellurium (Te), silver (Ag), and copper (Cu) as an impurity;
A method for producing a single crystal.
A single crystal is obtained by repeatedly executing the single crystal manufacturing method according to any one of claims 5 to 21;
A method for producing a single crystal.
Obtained by the method for producing a single crystal according to any one of claims 5 to 22,
A zinc oxide (ZnO) single crystal characterized by
A zinc oxide (ZnO) single crystal according to claim 23,
A crystal thickness that is a thickness of the crystal in a direction orthogonal to the surface of the seed substrate of the film formed in the film forming step exceeds 30 μm;
A zinc oxide (ZnO) single crystal characterized by
A zinc oxide (ZnO) single crystal according to claim 24,
It is obtained by the single crystal manufacturing method according to claim 22, and a crystal thickness that is a thickness of the crystal in a direction orthogonal to a surface of the seed substrate of the film formed in the film forming step exceeds 100 μm. ,
A zinc oxide (ZnO) single crystal characterized by
A zinc oxide (ZnO) single crystal according to any one of claims 23 to 25,
Containing at least one element selected from the group consisting of aluminum (Al), gallium (Ga), and indium (In) as impurities, and the impurity content is 0.02 at% or more. ,
A zinc oxide (ZnO) single crystal characterized by
A zinc oxide (ZnO) single crystal according to claim 26,
The impurity content is 0.1 at% or more,
A zinc oxide (ZnO) single crystal characterized by
A zinc oxide (ZnO) single crystal according to any one of claims 23 to 27,
Resistivity is 1 × 10 −3 Ω · cm or less,
A zinc oxide (ZnO) single crystal characterized by