JP2014055091A - Method for producing group iii-v compound crystal, method for producing seed crystals formed substrate, group iii-v compound crystal, semiconductor device, group iii-v compound crystal producing apparatus, seed crystals formed substrate producing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a group III-V compound crystal that may produce a large size group III-V compound crystal having few defects efficiently.SOLUTION: A method for producing a group III-V compound crystal 13 comprising: a seed crystals formed substrate providing step for providing a seed crystals formed substrate obtained by forming a plurality of group III-V compound seed crystals 12a on a substrate 11; a contact step for contacting the surface of the seed crystals 12a to a metal melt; and a crystal growth step for forming and growing a group III-V compound crystal 13 by reacting a group III element and a group V element in the metal melt using the seed crystals 12a as nuclei in which a plurality of the group III-V compound crystals grown from a plurality of the seed crystals 12a are joined by the growth of the group III-V compound crystal, in which a plurality of the seed crystals 12a are formed by removing a part of a group III-V compound layer 12 formed on the substrate 11 by a physical processing.

Description

  The present invention relates to a group III-V compound crystal manufacturing method, a seed crystal forming substrate manufacturing method, a group III-V compound crystal, a semiconductor device, a group III-V compound crystal manufacturing apparatus, and a seed crystal forming substrate manufacturing apparatus.

  III-V compound semiconductors (also called III-V semiconductors or GaN-based semiconductors) such as gallium nitride (GaN) are widely used as materials for various semiconductor elements such as laser diodes (LD) and light-emitting diodes (LEDs). It is used.

  As a method for easily producing a group III-V compound semiconductor, for example, a vapor phase epitaxy method (also simply referred to as “vapor phase growth method”) is used (Patent Documents 1 to 4). However, the vapor phase epitaxial growth method has a limited time for crystal growth, so that the thickness of the crystal to be grown is limited, and it is difficult to obtain a III-V group compound crystal having a large thickness.

  For this reason, a liquid phase growth method (LPE: Liquid Phase Epitaxy) in which crystals are grown in a liquid phase is used as a method capable of producing a higher quality III-V compound single crystal. This liquid phase growth method has a problem of requiring high temperature and high pressure, but recent improvements have made it possible to perform at a relatively low temperature and low pressure, making it suitable for mass production (patented) Literature 5-7). In the liquid crystal growth method (LPE), for example, a III-V compound crystal layer serving as a seed crystal is formed on a sapphire substrate by metal organic chemical vapor deposition (MOCVD), and then the liquid phase. A method of further growing the group III-V compound crystal by a growth method may be used (Patent Documents 5 to 7). Note that the metal organic chemical vapor deposition method (MOCVD) is a kind of vapor phase epitaxial growth method, and is used auxiliary to form a group III-V compound crystal layer that becomes a seed crystal.

Japanese Examined Patent Publication No. 7-54806 JP-A-10-305420 JP 2005-516415 gazette Japanese Patent No. 4562001 Japanese Patent No. 4920875 Japanese Patent No. 4422473 Japanese Patent No. 4588340

  In order to effectively use the III-V compound crystal industrially (for example, in a semiconductor device or the like), the size of the III-V compound crystal must be large enough to be effectively used. Further, it is preferable that defects such as distortion, dislocation, warpage and the like of the III-V group compound crystal are as small as possible. However, as described below, it is extremely difficult to produce a high-quality group III-V compound crystal having a large size and few defects such as distortion, dislocation, and warp by the conventional method for producing a group III-V compound crystal. It is.

  That is, first, when manufacturing a III-V compound crystal by vapor phase epitaxial growth or the like, a substrate for epitaxial growth is required. As this substrate, an inexpensive sapphire substrate is generally used. However, since the lattice constant, the thermal expansion coefficient, and the like are considerably different between the sapphire substrate and the III-V group compound crystal, defects such as strain, dislocation, and warp occur in the III-V group crystal. This defect problem becomes more prominent as the crystal becomes larger. In the present invention, “sapphire” refers to an aluminum oxide crystal or a crystal containing aluminum oxide as a main component unless otherwise specified.

  In order to solve the problem of the difference in lattice constant, it is conceivable to grow a III-V compound crystal from a III-V compound seed crystal having a large size and few defects, instead of the sapphire substrate. More specifically, for example, a group III-V compound substrate may be used instead of the sapphire substrate, and this may be used as a seed crystal. However, a large group III-V compound seed crystal such as a group III-V compound substrate is very expensive and therefore expensive. In addition, in the prior art, it is almost impossible to obtain a high-quality III-V compound seed crystal having a large size and few defects such as distortion, dislocation and warpage. For this reason, the grown group III-V compound crystal inherits the crystal defects of the seed crystal, and it is difficult to fundamentally solve the problem.

  In addition, as a method for producing a III-V group compound crystal having a large size and few defects, a method of growing a micro seed crystal in a liquid phase over a long period of time can be considered. However, it is extremely difficult to obtain large-sized crystals in this way.

  In view of the above, in Patent Documents 6 and 7, in order to produce a group III-V compound crystal with few defects, a plurality of group III-V compound crystals grown from a plurality of seed crystals formed on a substrate are grown. It is described that they are bound (associated). As a method for forming the plurality of seed crystals, in Patent Document 6, a plurality of seed crystals are formed by removing a part of the seed crystals formed (formed) on the substrate by vapor phase epitaxial growth by etching or the like. . In Patent Document 7, a mask film having a plurality of through holes is formed on a seed crystal formed (film formation) on a substrate by a vapor phase epitaxial growth method, and a portion exposed from the plurality of through holes is Multiple seed crystals are used. 17A to 17E schematically show an example of the method of Patent Document 6, and FIGS. 18A to 18C show an example of the method of Patent Document 7. Is shown schematically. 17 and 18, the left side is a plan view, and the right side is a cross-sectional view. 17 is a cross-sectional view seen in the BB ′ direction of the left side of the figure, and the right side cross-sectional view of FIG. 18 is a cross section seen in the CC ′ direction of the left side of the figure. FIG.

  In the method of FIG. 17, first, as shown in FIG. 17A, a laminated substrate in which a III-V compound layer 12 is formed on a substrate 11 is prepared. Next, as shown in FIG. 4B, a plurality of resists (etching masks) 15 are formed in a dot shape, stripe shape, or the like (dot shape in the figure) on a part of the III-V compound layer 12. And cover the III-V compound layer 12. In this state, when the III-V group compound layer 12 is treated with an etching solution or the like, the portion not covered with the resist 15 is removed and only the portion covered with the resist 15 is removed, as shown in FIG. It remains as seed crystal 12a. Further, the resist 15 is removed as shown in FIG. Then, a group III-V compound crystal is grown from each of the plurality of seed crystals 12a and bonded (associated) to form a group III-V compound crystal 13 as shown in FIG. On the other hand, in the method shown in FIG. 18, first, as shown in FIG. Next, as shown in FIG. 4B, a mask film 17 having a plurality of through holes in the form of dots, stripes, etc. (dots in the figure) is formed on the III-V compound layer 12, and III The V group compound layer 12 is covered. As a result, a plurality of portions exposed from the through holes (that is, not covered with the mask film 17) are defined as III-V group compound crystals 12a. Then, a group III-V compound crystal is grown from each of the seed crystals 12a and combined (associated) to form a group III-V compound crystal 13 as shown in FIG. According to these methods, the grown group III-V compound crystal is less likely to inherit defects such as dislocations of the seed crystal, rather than using the group III-V compound layer formed on the substrate as a seed crystal as it is. It is considered that a group III-V compound crystal with few defects is obtained.

  However, the methods of Patent Documents 6 and 7 have a risk that the crystal growth rate is lower and the crystal production efficiency is worse than using the seed crystal formed on the substrate as it is. In the methods of Patent Documents 6 and 7, it is difficult to completely remove residues such as an etching solution and a resist (etching mask) after etching. Therefore, due to these residues, the group III-V compound crystals grow with defects, or the grown group III-V compound crystals do not orderly and a large defect occurs on the associated surface. There is a risk. In addition, with the recent improvement in performance of semiconductor devices, III-V group compound crystals with fewer defects are required.

  Accordingly, the present invention provides a III-V compound crystal manufacturing method, a seed crystal-forming substrate manufacturing method, and a III-V group compound capable of efficiently manufacturing a high-quality III-V compound crystal having a large size and few defects. It is an object of the present invention to provide a crystal manufacturing apparatus and a seed crystal forming substrate manufacturing apparatus. Furthermore, the present invention provides a group III-V compound crystal and a semiconductor device that can be produced as described above.

In order to achieve the above object, the III-V compound crystal production method of the present invention comprises:
A seed crystal forming substrate providing step of providing a seed crystal forming substrate in which a plurality of group III-V compound seed crystals are formed on the substrate;
Contacting a surface of the plurality of group III-V compound seed crystals with a metal melt;
A crystal growth step in which a group III element and a group V element are reacted in the metal melt to generate and grow a group III-V compound crystal using the group III-V compound seed crystal as a nucleus,
In the crystal growth step, a plurality of III-V compound crystals grown from the plurality of III-V compound seed crystals are combined to grow a group III-V compound crystal. A manufacturing method comprising:
The plurality of group III-V compound seed crystals are group III-V compound seed crystals formed by physically removing a part of the group III-V compound layer formed on the substrate. It is characterized by.

The method for producing a seed crystal-forming substrate of the present invention is a method for producing the seed crystal-forming substrate used in the method for producing a group III-V compound crystal of the present invention,
A laminated substrate providing step of providing a laminated substrate in which a III-V group compound layer is laminated on the substrate;
A III-V compound seed crystal forming step of forming a plurality of III-V compound seed crystals by removing a part of the III-V compound layer by physical processing.

The group III-V compound crystal of the present invention is a group III-V compound crystal produced by the method for producing a group III-V compound crystal of the present invention, or a dislocation density of 1 × 10 ² cm ⁻² or less. This is a group III-V compound crystal.

  The semiconductor device of the present invention is a semiconductor device including the III-V group compound crystal of the present invention which is a semiconductor.

The III-V compound crystal production apparatus of the present invention comprises:
It is a manufacturing apparatus used for the III-V group compound crystal manufacturing method of the present invention,
The manufacturing apparatus includes a group III-V compound seed crystal forming unit that removes a part of the group III-V compound layer by physical processing to form the plurality of group III-V compound seed crystals.

The seed crystal forming substrate manufacturing apparatus of the present invention is
It is a manufacturing apparatus used for the seed crystal formation substrate manufacturing method of the present invention,
The manufacturing apparatus includes a group III-V compound seed crystal forming unit that removes a part of the group III-V compound layer by physical processing to form the plurality of group III-V compound seed crystals.

  According to the III-V compound crystal manufacturing method, the seed crystal forming substrate manufacturing method, the III-V compound crystal manufacturing apparatus, and the seed crystal forming substrate manufacturing apparatus of the present invention, a high-quality III with a large size and few defects. A group V compound crystal can be produced efficiently. Moreover, according to this invention, the III-V group compound crystal and semiconductor device which can be manufactured by the above can be provided.

FIG. 1 is a process diagram schematically showing an example of a method for producing a group III-V compound crystal of the present invention. FIG. 2 is a process cross-sectional view schematically showing another example of the method for producing a group III-V compound crystal of the present invention. FIG. 3 is a process plan view schematically showing still another example of the method for producing a group III-V compound crystal of the present invention. FIG. 4 is a perspective view schematically showing still another example of the method for producing a group III-V compound crystal of the present invention. FIG. 5 is a perspective view showing an example of a laser processing apparatus that can be used as the III-V group compound crystal manufacturing apparatus of the present invention or the seed crystal forming substrate manufacturing apparatus of the present invention. FIG. 6 is a perspective view of a state in which a workpiece in the laser processing apparatus of FIG. 5 is fixed to a frame. FIG. 7 is a perspective view showing a state in which the workpiece of FIG. 6 is positioned below the condenser in the laser beam irradiation means. FIG. 8 is a view showing a state in which the workpiece of FIG. 6 is positioned below the condenser in the laser beam irradiation means. FIG. 8A is a front view, and FIG. 8B is a cross-sectional view. FIG. 9 is a schematic diagram and a photograph showing a group III-V compound seed crystal and its arrangement in the examples. FIG. 10 is a photograph of a group III-V compound crystal grown from the group III-V compound seed crystal of FIG. FIG. 11 is a schematic diagram showing the size, shape, and arrangement of a group III-V compound seed crystal in a reference example. FIG. 12 is a photograph illustrating the shape of the group III-V compound seed crystal of FIG. FIG. 13 is a photograph of a group III-V compound crystal grown from the group III-V compound seed crystal of FIGS. FIG. 14 is a photograph showing a longitudinal section of a group III-V compound crystal produced in another example. FIG. 15 is a photograph showing a longitudinal section of a group III-V compound crystal produced in yet another example. FIG. 16 is a diagram schematically illustrating the structure of the LPE apparatus used in the example. FIG. 17 is a process diagram schematically showing an example of a method for producing a group III-V compound crystal. FIG. 18 is a process diagram schematically showing another example of a method for producing a group III-V compound crystal.

  Hereinafter, the present invention will be described with examples. However, the present invention is not limited by the following description.

<1. Method for Producing III-V Group Compound Crystal>
The manufacturing method of the III-V group compound crystal | crystallization of this invention can be performed as follows, for example.

<1-1. Step of providing seed crystal forming substrate>
First, a seed crystal forming substrate in which a plurality of group III-V compound seed crystals (hereinafter sometimes simply referred to as “seed crystals”) is formed on the substrate is provided (seed crystal forming substrate providing step). The plurality of seed crystals are seed crystals formed by physically removing a part of the III-V group compound layer formed on the substrate. In the seed crystal formation substrate providing step, a seed crystal formation substrate prepared in advance may be obtained, or may be manufactured by the method for manufacturing a seed crystal formation substrate of the present invention.

  As described above, the method for producing a seed crystal-forming substrate of the present invention includes a laminated substrate providing step of providing a laminated substrate in which a III-V group compound layer is laminated on a substrate, and a part of the III-V group compound layer. And a III-V compound seed crystal forming step of forming the plurality of III-V compound seed crystals by physical processing. Hereinafter, the laminated substrate providing step and the III-V group compound seed crystal forming step will be described with examples.

<1-1-1. Laminated substrate provision process>
First, as shown in FIG. 1A, a laminated substrate in which a III-V group compound layer 12 is laminated on a substrate 11 is provided (a laminated substrate providing step). The laminated substrate may be prepared in advance or manufactured. In the case of manufacturing, for example, the III-V group compound layer can be stacked on the substrate by the seed crystal forming substrate manufacturing method of the present invention. Although the substrate 11 is not particularly limited, for example, a sapphire substrate, a silicon carbide substrate, a gallium oxide (Ga ₂ O ₃ ) substrate, a silicon (Si) substrate, a silicon nitride (also referred to as Si ₃ N ₄ , silicon nitride) substrate, gallium, for example. Examples thereof include an arsenic (GaAs) substrate and a lithium aluminate (LiAlO ₂ ) substrate. The shape and size of the substrate 11 are not particularly limited, and can be appropriately set according to, for example, the shape and size of the group III-V compound crystal to be manufactured. The shape of the substrate may be, for example, a rectangle as shown in FIG. 1A, or may be a circle, a polygon, a square, a hexagon, an octagon, or the like. The size of the substrate 11 may be, for example, a major axis of 5 to 20 cm. Although the thickness of the board | substrate 11 is not specifically limited, For example, it is 0.01-2 mm, Preferably it is 0.05-1.5 mm, More preferably, it is 0.1-1 mm. The thickness of the III-V compound layer 12 is not particularly limited, but is, for example, 0.5 to 1000 μm, preferably 1 to 100 μm, more preferably 5 to 50 μm, and further preferably 5 to 30 μm. The method for forming the III-V compound layer 12 is not particularly limited, and may be, for example, a vapor phase epitaxial growth method or a liquid phase growth method. In the present invention, examples of the group III (group 13) element include aluminum (Al), gallium (Ga), and indium (In), and examples of the group V (group 15) element include nitrogen ( N), phosphorus (P), arsenic (As), and antimony (Sb). The III-V group compound layer 12 may be formed of, for example, Al _x Ga _y In _1-xy N or Al _x Ga _y In _1-xy P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1). III-V group compounds represented by (II) may be used, and group III nitrides are preferred. More specifically, examples of the III-V group compound layer 12 include AlGaN, InGaN, InAlGaN, AlN, GaP, and GaN represented by the above-mentioned composition, and GaN is particularly preferable.

<1-1-2. III-V Group Seed Crystal Formation Step>
Next, as shown in FIG. 1B, a part of the group III-V compound layer 12 is removed by physical processing to form a plurality of group III-V compound seed crystals 12a (group III-V). Compound seed crystal formation step). Thereby, the plurality of group III-V compound seed crystals can be easily formed without using a resist (etching mask), an etching solution, or the like. The physical processing is not particularly limited, and examples thereof include cutting processing or processing by causing particles or waves to collide with the III-V group compound layer. Among these, processing by causing particles or waves to collide with the III-V group compound layer is preferable. Examples of processing by causing particles or waves to collide with the III-V group compound layer include, for example, laser light irradiation, particle (ion or electron) beam irradiation, milling processing, shot blasting, abrasive water jet, and ultrasonic processing. Etc. Among these, laser beam irradiation is particularly preferable. This is because, according to the laser beam irradiation, precise processing can be performed more easily. Specifically, for example, the portion of the III-V group compound layer to be removed may be irradiated with laser light. The wavelength of the laser beam is not particularly limited, but it is preferably a wavelength that can remove a portion of the III-V group compound layer that is desired to be removed without affecting the substrate. For this purpose, the wavelength of the laser beam is preferably a wavelength that is absorbed by the III-V group compound layer and transmits through the substrate. In this case, the absorption rate of the laser beam with respect to the III-V group compound layer is, for example, 20% or more, preferably 50% or more, particularly preferably 80% or more, and ideally 100%. The transmittance of the laser beam with respect to the substrate is, for example, 90% or more, preferably 95% or more, particularly preferably 98% or more, and ideally 100%. In addition, although the measuring method of the absorption factor with respect to the said III-V group compound layer and the transmittance | permeability with respect to the said board | substrate of the said laser beam is not specifically limited, For example, it can measure using a common spectrophotometer. The wavelength of the laser beam is, for example, 150 to 1300 nm, preferably 193 to 1100 nm, more preferably 193 to 500 nm, and still more preferably 193 to 400 nm. The wavelength of the laser beam can be appropriately set in consideration of the material of the substrate and the III-V compound layer. When the substrate is a sapphire substrate and the III-V compound layer is GaN, the wavelength of the laser light is preferably 200 to 500 nm, more preferably 200 to 350 nm, and particularly preferably 230 to 300 nm. More specifically, for example, laser light having a wavelength of 266 nm or 355 nm can be used.

Although the output of the laser beam is not particularly limited, it is, for example, 0.01 to 100 W, preferably 0.05 to 50 W, more preferably 1 to 20 W. The spot diameter of the laser beam is not particularly limited, but is, for example, 1 to 400 μm, preferably 5 to 150 μm, and more preferably 10 to 80 μm. Energy density of the laser beam is not particularly limited, for example, 0.001~20J / cm ^2, preferably 0.002~10J / cm ^2, more preferably 0.006~5J / cm ^2. The moving speed (feeding speed) of the laser beam spot is not particularly limited, but is, for example, 1 to 1000 mm / s, preferably 10 to 500 mm / s, and more preferably 50 to 300 mm / s. The direction in which the laser beam is irradiated is not particularly limited. For example, the irradiation may be performed from the group III-V compound layer side, and the group III-V compound layer may be irradiated from the substrate side through the substrate. However, irradiation from the III-V group compound layer side is preferable. Further, the laser beam medium and the oscillator are not particularly limited, and examples thereof include a YAG laser, a CO ₂ laser, a YVO ₄ laser, a YLF laser, a disk laser, a DPSS laser, an excimer laser, and a fiber laser. The laser beam may be a pulse laser beam or a CW (Continuous wave) laser beam. In the case of a pulse laser beam, the frequency is not particularly limited, but is, for example, 10 Hz to 100 MHz, preferably 1 to 1000 kHz (1 MHz), and more preferably 10 to 200 kHz. The pulse width of the pulse laser beam is not particularly limited, but from the viewpoint of suppressing thermal diffusion, for example, 0.2 ps (0.2 picosecond or 200 fs [femtosecond]) to 10 ns, preferably 5 to 500 ps (picosecond). More preferably, it is 5 to 200 ps.

  The shape of the group III-V compound seed crystal 12a is not particularly limited, and examples thereof include a stripe shape and a dot shape, and a dot shape is particularly preferable. In the case of a dot shape, the shape may be, for example, a circle as shown in FIG. 1B, or an ellipse, a polygon, a regular polygon, a triangle, a regular triangle, a quadrangle, a square, a rectangle, a pentagon, and a regular pentagon. , Hexagons, regular hexagons, etc. The size of the group III-V compound seed crystal 12a is not particularly limited. However, the smaller the group III-V compound seed crystal 12a, the easier it is to obtain a high-quality group III-V compound crystal in the later-described crystal growth step. The reason for this is not clear, but it is considered that the smaller the group III-V compound seed crystal 12a, the more difficult crystal defects such as dislocations are inherited by the grown group III-V compound crystal. When the group III-V compound crystal 12a has a stripe shape, the width thereof is, for example, 1 mm or less, preferably 0.5 mm or less, more preferably 0.3 mm or less, and the lower limit value is not particularly limited. That's it. When the group III-V compound crystal 12a has a dot shape, the long diameter of the dot (the longest diameter, for example, the long side in the case of a rectangle) is, for example, 1.0 mm or less, preferably 0.5 mm or less, more preferably 0. .3 mm or less, particularly preferably 0.25 mm or less. The lower limit value of the major axis of the dots is not particularly limited, and the smaller the better, the better, for example, 0.01 mm or more. The interval between the seed crystals 12a adjacent to each other is, for example, 0.01 to 10 mm, preferably 0.05 to 5 mm, more preferably 0.1 to 1.0 mm, still more preferably 0.15 to 0.75 mm, Especially preferably, it is 0.2-0.5 mm. The arrangement of the seed crystal 12a is not particularly limited. For example, as shown in FIG. 1B, it is assumed that a plurality of congruent rectangles (rectangles) are spread on the substrate 11 without gaps, and the seed crystal 12a may be arranged at each vertex of the rectangle. Instead of the rectangle, for example, a square, a rhombus, a trapezoid, or the like may be used. For example, as shown in FIG. The arrangement relationship between the seed crystals 12a adjacent to each other is not particularly limited. For example, the same planes of crystal planes (a-plane, c-plane or m-plane in the case of hexagonal crystal) generated and grown from various adjacent crystals may be arranged so as to be substantially parallel. good. Alternatively, the same axes among the crystal axes (a-axis, c-axis, or m-axis in the case of hexagonal crystal) generated from the various crystals adjacent to each other may be arranged so as to overlap each other. In this case, the angle formed by the crystal planes or crystal axes is preferably less than 30 °, more preferably 5 ° or less, still more preferably 1 ° or less, still more preferably 0.1 ° or less, More preferably, it is 0.02 ° or less, and particularly preferably 0 °. Further, the arrangement of the group III-V compound seed crystal is not limited to these, and may be any arrangement such as a spiral shape, a concentric circle shape, and a radial shape.

  As described above, the seed crystal forming substrate providing step can be performed. However, these are examples, and the seed crystal formation substrate providing step in the present invention is not limited to these.

<1-2. Contact process and crystal growth process>
Next, the surfaces of the plurality of group III-V compound seed crystals are brought into contact with the metal melt (contacting step). Further, by reacting the group III element and the group V element in the metal melt, a group III-V compound crystal is generated and grown using the seed crystal as a nucleus (crystal growth step).

The composition of the group III-V compound crystal produced and grown from the seed crystal may be the same as or different from the composition of the seed crystal (composition of the group III-V compound layer in the multilayer substrate). Are preferably the same. The III-V group compound crystal is, for example, Al _x Ga _y In _1-xy N or Al _x Ga _y In _1-xy P (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1). III-V compound crystals represented by (II) may be used, and group III nitride crystals are preferable. More specifically, examples of the III-V group compound crystal include AlGaN, InGaN, InAlGaN, AlN, GaP, GaN and the like represented by the above-mentioned composition, and GaN is particularly preferable. The composition of the group III-V crystal can be adjusted by the type and amount ratio of the group III element and the group V element in the crystal growth step. For example, when the group III-V compound crystal is a group III nitride crystal, the group V element to be reacted in the crystal growth step is preferably nitrogen. In this case, the metal melt is an alkali metal melt, and in the crystal growth step, a group III element and the nitrogen are reacted in the alkali metal melt in an atmosphere containing nitrogen. More preferably, a group III nitride crystal is generated and grown using the seed crystal as a nucleus.

  The contact step and the crystal growth step can be performed as follows, for example.

In the contact step and the crystal growth step, for example, a sodium flux method (Na flux method), which is one of manufacturing methods of gallium nitride (GaN) used for a semiconductor substrate of an LED or a power device, may be used. good. For example, first, a seed crystal (for example, a GaN thin film formed on a sapphire substrate) is set in a crucible. Moreover, sodium (Na) and gallium (Ga) are accommodated in the crucible together with the seed crystal in an appropriate ratio. Next, sodium and gallium in the crucible are melted in an environment of high temperature (for example, 800 to 1000 ° C.) and high pressure (for example, several tens of atmospheres), and nitrogen gas (N ₂ ) is introduced into the melt. Let it melt. Thereby, the GaN seed crystal in the said crucible can be grown and the target GaN crystal can be manufactured. The reaction conditions in the method for producing a group III-V compound crystal of the present invention may be performed, for example, by the same method as in the general sodium flux method or by appropriately changing it. For example, Ga may be any other group III element. The nitrogen gas may be other nitrogen-containing gas as described below.

In the production method of the present invention, when the crystal growth step is performed in an atmosphere containing nitrogen, the form of nitrogen in the “atmosphere containing nitrogen” is not particularly limited. For example, gas, nitrogen molecule, nitrogen compound Etc. The “under nitrogen-containing atmosphere” is preferably a nitrogen-containing gas atmosphere. This is because the nitrogen-containing gas dissolves in the flux and becomes a raw material for growing a group III-V compound crystal. As the nitrogen-containing gas, other nitrogen-containing gas such as ammonia gas (NH ₃ ) may be used in addition to or instead of the nitrogen gas (N ₂ ) described above. When a mixed gas of nitrogen gas and ammonia gas is used, the mixing rate is arbitrary. In particular, use of ammonia gas is preferable because the reaction pressure can be reduced.

  The alkali metal melt (flux) may use other alkali metals such as lithium in addition to or in place of sodium. More specifically, the alkali metal melt is at least selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). For example, it may be a mixed flux of Na and Li. The alkali metal melt is particularly preferably a sodium melt. Further, the alkali metal melt may or may not contain one or more kinds of components other than alkali metals. The component other than the alkali metal is not particularly limited, and examples thereof include an alkaline earth metal. Examples of the alkaline earth metal include calcium (Ca), magnesium (Mg), strontium (Sr), and barium. There are (Br) and radium (Ra). Among them, Ca and Mg are preferable, and Ca is more preferable. Moreover, as a component other than the alkali metal, for example, carbon (carbon simple substance or carbon compound) may or may not be included. Preferred are simple carbon and carbon compounds that generate cyan (CN) in the melt. Carbon may be a gaseous organic substance. Examples of such carbon simple substance and carbon compound include cyanide, graphite, diamond, fullerene, carbon nanotube, methane, ethane, propane, butane, and benzene. The carbon content is not particularly limited, and is, for example, in the range of 0.01 to 20 atoms (at.)%, 0.05 to 15 based on the total of the melt, the group III element, and the carbon. Atom (at.)% Range, 0.1 to 10 atom (at.)% Range, 0.1 to 5 atom (at.)% Range, 0.25 to 7.5 atom (at.)% Range, 0.25-5 atom (at.)% Range, 0.5-5 atom (at.)% Range, 0.5-2.5 atom (at.)% Range, 0.5 In the range of ~ 2 atoms (at.)%, In the range of 0.5-1 atoms (at.)%, In the range of 1-5 atoms (at.)%, Or in the range of 1-2 atoms (at.)%. is there. Among these, the range of 0.5-5 atom (at.)%, The range of 0.5-2.5 atom (at.)%, The range of 0.5-2 atom (at.)%, 0.5 A range of ˜1 atom (at.)%, A range of 1 to 5 atom (at.)%, Or a range of 1 to 2 atom (at.)% Is preferred.

  The addition ratio of the alkali metal to the group III element is, for example, 0.1 to 99.9 mol%, preferably 1 to 99 mol%, more preferably 5 to 98 mol%. The molar ratio when using a mixed flux of alkali metal and alkaline earth metal is, for example, alkali metal: alkaline earth metal = 99.99 to 0.01: 0.01 to 99.99, preferably 99. .9 to 0.05: 0.1 to 99.95, more preferably 99.5 to 1: 0.5 to 99. The purity of the melt is preferably high. For example, the purity of Na is preferably 99.95% or more. As the high purity flux component (for example, Na), a commercially available product having a high purity may be used, or a product obtained by increasing the purity by a method such as distillation after purchasing a commercially available product may be used.

  The reaction temperature and pressure between the group III element and the nitrogen-containing gas are not limited to the above values, and may be set as appropriate. The appropriate reaction temperature and pressure vary depending on the components of the melt (flux), the atmospheric gas components, and the pressure thereof. For example, the temperature is 100 to 1500 ° C., the pressure is 100 Pa to 20 MPa, and preferably the temperature is 300 to 1200 ° C. The pressure is 0.01 MPa to 20 MPa, more preferably the temperature is 500 to 1100 ° C., the pressure is 0.1 MPa to 10 MPa, and further preferably the temperature is 700 to 1100 ° C. and the pressure is 0.1 MPa to 10 MPa. The reaction time, that is, the crystal growth (growth) time is not particularly limited, and may be set as appropriate so that the crystal grows to an appropriate size. For example, it is 1 to 1000 hr, preferably 5 to 600 hr. Preferably, it is 10 to 400 hours.

In the production method of the present invention, in some cases, the seed crystal may be dissolved by the flux before the nitrogen concentration increases. In order to prevent this, nitride may be present in the flux at least at the initial stage of the reaction. Examples of the nitride include Ca ₃ N ₂ , Li ₃ N, NaN ₃ , BN, Si ₃ N ₄ , and InN. These may be used alone or in combination of two or more. Good. Moreover, the ratio in the said flux of the said nitride is 0.0001 mol%-99 mol%, for example, Preferably, it is 0.001 mol%-50 mol%, More preferably, it is 0.005 mol%-10 mol%.

In the production method of the present invention, impurities can be present in the mixed flux. In this way, an impurity-containing GaN crystal can be manufactured. Examples of the impurities include silicon (Si), alumina (Al ₂ O ₃ ), indium (In), aluminum (Al), indium nitride (InN), silicon oxide (SiO ₂ ), and indium oxide (In ₂ O ₃ ). Zinc (Zn), magnesium (Mg), zinc oxide (ZnO), magnesium oxide (MgO), germanium (Ge), and the like.

  The production method of the present invention may further include a stirring step of stirring the melt. The step of performing the stirring step is not particularly limited, and may be performed, for example, at least one before the crystal growth step, at the same time as the crystal growth step, and after the crystal growth step. More specifically, for example, it may be performed before the crystal growth step, simultaneously with the crystal growth step, or both.

  Moreover, for the reaction conditions in the contact step and the crystal growth step, for example, the reaction conditions described in Patent Documents 5 to 7 may be referred to. For example, an apparatus used for the contact process and the crystal growth process is not particularly limited, but may be the same as an apparatus (LPE apparatus) used for a general liquid phase growth method. It may be the same.

  As described above, the contact step and the crystal growth step can be performed. However, these are merely examples, and the contact step and the crystal growth step in the present invention are not limited to these.

  2 and 3 schematically show an example of a state of growth of a group III-V crystal in the crystal growth step. 2 is a cross-sectional view, and FIG. 3 is a plan view. However, FIG. 2 is not a strict representation of the cross section of FIG.

  First, as shown in FIG. 2A and FIG. 3A, a seed crystal forming substrate in which a plurality of group III-V compound seed crystals 12a are formed on a substrate 11 is provided (seed crystal forming substrate providing step). . This is subjected to the contact step in contact with the metal melt, and further to the crystal growth step as shown in FIGS. 2 (b) to (e) or FIGS. 3 (b) to (e). That is, first, as shown in FIG. 2B or FIG. 3B, a III-V group crystal 13 is generated from the seed crystal 12a and grows. This III-V group crystal 13 further grows and bonds as shown in FIG. 2 (c) or FIG. 3 (c). This is further grown as shown in FIG. 2D or FIG. 3D, and then cut along the dotted line 14 as necessary. The cutting direction may be a direction parallel to the substrate plane, as shown in FIG. 2D or FIG. 3D, or any other direction. Further, as the group III-V crystal 13 after cutting, as shown in FIG. 2 (e) or FIG. 3 (e), the one laminated (bonded) to the substrate 11 may be used, or the other is used. May be.

  In FIG. 3, the crystal 13 generated and grown from the seed crystal 12 a is a hexagonal crystal, and the seed crystal 12 a is arranged so that the a axes of the crystals 13 adjacent to each other overlap each other. However, as described above, the arrangement of the group III-V compound seed crystal is not limited to this.

  In addition, the III-V group compound manufactured by the manufacturing method of the III-V group crystal | crystallization of this invention (For example, in the state of FIG.2 (d) or (e) or FIG.3 (d) or (e)) The thickness of the crystal is not particularly limited, but is, for example, 0.01 mm or more, preferably 0.05 mm or more, more preferably 0.1 mm or more, further preferably 0.2 mm or more, and particularly preferably 0.4 mm or more. According to the present invention, for example, a group III-V compound crystal having a thickness exceeding several mm can be produced. Further, beyond this, the thickness of the III-V group compound crystal can be increased to a limit limited by the size of the crystal growth (growth) vessel. The upper limit value of the thickness of the III-V group compound crystal is not particularly limited and is preferably as large as possible, but is, for example, 300 mm or less. As the thickness of the group III-V compound crystal is larger, a larger number of products (for example, a group III-V compound substrate for a semiconductor device) manufactured from the group III-V compound crystal can be cut out. The method for cutting out the product is not particularly limited. For example, the group III-V compound crystal may be sliced to a thickness suitable for the product and cut into a size suitable for the product. However, as described above, the thickness of the group III-V compound crystal produced by the method for producing a group III-V compound crystal of the present invention is not particularly limited.

  According to the method for producing a group III nitride crystal of the present invention, as described above, a high-quality group III-V compound crystal having a large size and few defects can be efficiently produced. The reason for this is not clear, but it is presumed that since there is no use of an etching resist (etching mask), an etching solution, a mask film having a through-hole, etc., they have no influence on crystal growth. Therefore, according to the present invention, it is considered that a crystal with fewer defects such as dislocations can be produced more efficiently than a method using an etching resist (etching mask), an etching solution, a mask film having a through hole, and the like. It is done.

  Note that, in the contact step and the crystal growth step, as shown in FIG. 4A, a plurality of stacked substrates in which a plurality of seed crystals 12a are formed on the substrate 11 may be arranged. That is, from the state of FIG. 4A, the contact step and the crystal growth step are performed to grow (grow) the crystal 13. Thereby, the grown crystal | crystallization couple | bonds within each unit shown in figure, and as shown in FIG.4 (b), the one big crystal | crystallization 13 can be manufactured.

  Recent advances in technology have made it possible to manufacture large-sized semiconductor crystals, thereby expanding the range of semiconductor device designs. For example, in a silicon semiconductor substrate or the like, a large-sized crystal having a diameter of 6 inches (about 15 cm), 8 inches (about 20 cm), 12 inches (about 30 cm), 18 inches (about 45 cm) or the like has been put into practical use, or Practical application is under consideration. However, it has been impossible to produce such a large crystal in a group III-V compound crystal such as GaN. According to the conventional method for producing a group III-V compound crystal, during the production or use of the crystal due to the difference in thermal expansion coefficient between the substrate (for example, sapphire substrate) and the crystal (for example, GaN crystal). The warpage of the substrate may cause crystal warpage, distortion, cracking, and the like. This problem becomes more prominent if a large group III-V compound crystal is produced using a large substrate. For example, in addition to the crystal being easily broken, it is considered that the crystal defects inherited by the crystal grown from the seed crystal are further increased due to the warp, distortion, etc. of the crystal. Up to now, III-V group compound crystals such as GaN have been manufactured using a 2-inch substrate (diameter: about 5 cm), and no III-V group compound crystals larger than the size of the substrate have been manufactured.

  However, for example, as shown in FIG. 4, by arranging a plurality of the laminated substrates in parallel, it is possible to manufacture a large-sized crystal while reducing problems such as crystal warpage, distortion, and cracking due to substrate warpage. it can. That is, by arranging a plurality of the laminated substrates in parallel, the III-V group compound crystal is not limited to the size of the laminated substrate itself, but is limited by the size of the crystal growth (growing) vessel. Can be increased.

  In FIG. 4, 2 × 2 = 4 stacked substrates are arranged in the vertical and horizontal directions, but the number to be arranged is not limited to this, and is arbitrary, for example, 1 × 2 = 2 vertical and horizontal, and 1 × 3 = 3 vertical and horizontal. The number may be 3 or 3 × 3 = 9.

<1-3. Substrate separation process>
The method for producing a group III-V crystal of the present invention may or may not include steps other than the seed crystal formation substrate providing step, the contact step, and the crystal growth step as appropriate. . For example, the method for producing a group III-V crystal of the present invention may or may not further include a substrate separation step for separating the group III-V compound crystal from the substrate. That is, the group III-V crystal produced by the method for producing a group III-V crystal of the present invention may be used while being stacked on the substrate, or may be used separately from the substrate. If the group III-V crystal has a thickness large enough to eliminate the need for reinforcement by the substrate, high performance when used in a semiconductor device or the like (for example, for light emitting elements such as LDs and LEDs). (Improvement of brightness when there is).

  The substrate separation step can be performed as follows, for example.

  That is, first, by irradiating the III-V group compound crystal with laser light from the substrate side, the bond between the III-V group compound crystal and the substrate is broken (bond breaking step). Thereafter, the substrate is peeled from the III-V group compound crystal (substrate peeling step). For example, when the III-V group compound crystal contains a gallium (Ga) element, by irradiating the bonding portion with the substrate with laser light, the bonding portion is destroyed and changed to metal gallium. Since metallic gallium has a melting point of about 30 ° C., the group III-V compound crystal can be easily peeled from the substrate. Moreover, even when the III-V group compound crystal does not contain a gallium (Ga) element, it becomes easy to peel from the substrate by breaking the bond with the substrate by laser light irradiation. In the substrate separation step, the separation point between the group III-V compound crystal and the substrate is not particularly limited. Specifically, for example, it may be separated at the interface between the group III-V compound crystal and the substrate, or a part of the group III-V compound crystal (for example, the group III-V compound seed crystal). A part of the derived part) may remain on the substrate.

  The reason for irradiating the laser beam from the substrate side in the bond breaking step is to not break the portion other than the bond portion with the substrate in the III-V group compound crystal. For this reason, the wavelength of the laser beam is a wavelength that is absorbed by the III-V group compound layer and passes through the substrate. Specifically, the absorption rate of the laser beam with respect to the III-V group compound layer is, for example, 20% or more, preferably 50% or more, particularly preferably 80% or more, and ideally 100%. . The transmittance of the laser beam with respect to the substrate is, for example, 90% or more, preferably 95% or more, particularly preferably 98% or more, and ideally 100%. In addition, although the measuring method of the absorption factor with respect to the said III-V group compound layer and the transmittance | permeability with respect to the said board | substrate of the said laser beam is not specifically limited, For example, it can measure using a common spectrophotometer. More preferably, the wavelength of the laser beam in the bond breaking step is longer than the absorption edge of the substrate and shorter than the absorption edge of the III-V group compound crystal. The wavelength of the laser beam is, for example, 193 to 1300 nm, preferably 193 to 1100 nm, more preferably 193 to 500 nm, and still more preferably 193 to 400 nm. The wavelength of the laser beam can be appropriately set in consideration of the material of the substrate and the III-V compound layer. When the substrate is a sapphire substrate and the III-V group compound crystal is a GaN crystal, the wavelength of the laser light is preferably 193 to 500 nm, more preferably 193 to 355 nm, and still more preferably 200 to 350 nm, particularly Preferably it is 230-300 nm.

The output of the laser beam is not particularly limited, but is, for example, 0.01 to 100 W, preferably 0.1 to 20 W, and more preferably 1 to 20 W. The spot diameter of the laser beam is not particularly limited, but is, for example, 1 to 400 μm, preferably 5 to 100 μm, and more preferably 10 to 80 μm. Energy density of the laser beam is not particularly limited, for example, 0.001~20J / cm ^2, preferably 0.002~10J / cm ^2, more preferably 0.003~2J / cm ^2. The moving speed (feeding speed) of the laser beam spot is not particularly limited, but is, for example, 1 to 1000 mm / s, preferably 10 to 500 mm / s, and more preferably 50 to 300 mm / s. The direction in which the laser beam is irradiated is not particularly limited. For example, the irradiation may be performed from the group III-V compound layer side, and the group III-V compound layer may be irradiated from the substrate side through the substrate. However, irradiation from the III-V group compound layer side is preferable. Further, the laser beam medium and the oscillator are not particularly limited, and examples thereof include a YAG laser, a CO ₂ laser, a YVO ₄ laser, a YLF laser, a disk laser, a DPSS laser, an excimer laser, and a fiber laser. The laser beam may be a pulse laser beam or a CW (Continuous wave) laser beam, but a pulse laser beam is preferable. In the case of a pulse laser beam, the frequency is not particularly limited, but is, for example, 10 Hz to 100 MHz, preferably 1 to 1000 kHz (1 MHz), and more preferably 10 to 200 kHz. The pulse width of the pulse laser beam is not particularly limited, but is, for example, 0.2 ps (200 fs) to 10 ns, preferably 0.2 to 500 ps, more preferably 5 to 200 ps. The pulse width maintains the quality by narrowing the thermal decomposition reaction region at the interface between the III-V compound and the substrate to ensure releasability and preventing excessive heat input to the compound substrate. Therefore, the pulse width is preferably such that the thermal diffusion length is 200 nm or less, for example, 200 ps or less.

  The substrate separation step can be performed as described above. For example, when the III-V group compound crystal of the present invention is used for a light emitting layer of a light emitting element (for example, LD, LED, etc.), the sapphire substrate used for crystal growth does not contribute to light emission. For this reason, the light emitting layer may be bonded to a reflective substrate made of molybdenum or the like, and then the sapphire substrate or the like may be peeled off (lifted off) from the light emitting layer.

  In the method for producing a group III-V compound crystal of the present invention, for example, as described above, the substrate used for crystal growth may be used without being separated from the group III-V compound crystal. The grown III-V group compound crystal may be used as it is, or may be used in a semiconductor device or the like after being divided into a plurality together with the substrate or after being separated from the substrate. Conversely, as shown in FIG. 4, a plurality of the substrates may be used and a larger group III-V compound crystal may be used.

<2. Group III-V compound crystal manufacturing apparatus, seed crystal forming substrate manufacturing apparatus>
Next, a group III-V compound crystal manufacturing apparatus and a seed crystal forming substrate manufacturing apparatus of the present invention will be described.

  The method for producing a group III-V compound crystal of the present invention may be performed using any method, but is preferably performed using the apparatus for producing a group III-V compound crystal of the present invention. The seed crystal forming substrate manufacturing method of the present invention may be performed using any method, but is preferably performed using the seed crystal forming substrate manufacturing apparatus of the present invention.

  The III-V compound crystal manufacturing apparatus of the present invention is a manufacturing apparatus used for the III-V compound crystal manufacturing method of the present invention as described above, and a part of the III-V compound layer is physically disposed. It is a manufacturing apparatus including a group III-V compound seed crystal forming unit that is removed by processing to form the plurality of group III-V compound seed crystals. When the III-V group compound crystal manufacturing method of the present invention includes the substrate separation step, the manufacturing apparatus irradiates the III-V group compound crystal with laser light from the substrate side in the substrate separation step. It is preferable to further include a substrate separation laser light irradiation means. Moreover, the seed crystal forming substrate manufacturing apparatus of the present invention is a manufacturing apparatus used for the seed crystal forming substrate manufacturing method of the present invention, wherein a part of the III-V group compound layer is removed by physical processing, and It is a manufacturing apparatus including a group III-V compound seed crystal forming means for forming a plurality of group III-V compound seed crystals. In the seed crystal-forming substrate manufacturing apparatus of the present invention, the physical processing is laser light irradiation, and the III-V group compound seed crystal forming unit irradiates a part of the III-V compound layer with laser light. Preferably, it is a group III-V compound seed crystal forming laser beam irradiation means that forms the group III-V compound seed crystal.

  Hereinafter, the III-V compound crystal manufacturing apparatus and the seed crystal forming substrate manufacturing apparatus of the present invention will be described in detail with examples. However, the III-V group compound crystal manufacturing apparatus and seed crystal forming substrate manufacturing apparatus of the present invention are not limited to the following examples.

  The perspective view of FIG. 5 shows an example of a laser processing apparatus that can be used as the III-V group compound crystal manufacturing apparatus of the present invention or the seed crystal forming substrate manufacturing apparatus of the present invention. As illustrated, the laser processing apparatus 10 includes a stationary base 20, a holding table mechanism 30, a laser light irradiation unit support mechanism 40, and a laser light irradiation unit 50. The holding table mechanism 30 is installed on the stationary base 20, holds the workpiece, and is movable in the machining feed direction indicated by the arrow X. The laser beam irradiation unit support mechanism 40 is installed on the stationary base 20 and is movable in the indexing feed direction indicated by the arrow Y. The arrow Y is orthogonal to the machining feed direction indicated by the arrow X as shown. The laser beam irradiation unit 50 is attached to the laser beam irradiation unit support mechanism 40 and is movable in the condensing point position adjustment direction indicated by the arrow Z. The arrow Z is orthogonal to the arrows X and Y as shown.

  The holding table mechanism 30 includes a guide rail 310, a first sliding block 320, a second sliding block 330, a cylindrical support cylinder 340, a cover table 350, and a holding table 360. There are two (a pair) guide rails 310, which are arranged on the stationary base 20 in parallel along the machining feed direction indicated by the arrow X. The first sliding block 320 is disposed on the pair of guide rails 310 and is movable in the machining feed direction indicated by the arrow X. The second sliding block 330 is disposed on the first sliding block 320 and is movable in the indexing feed direction indicated by the arrow Y. The cover table 350 and the holding table 360 as the workpiece holding means are supported on the second sliding block 330 by a cylindrical support cylinder 340.

  On the lower surface of the first sliding block 320, two (a pair) guided grooves 3210 that fit into the pair of guide rails 310 are provided. In addition, two (a pair) guide rails 3220 are formed on the upper surface of the first sliding block 320 in parallel along the index feed direction indicated by the arrow Y. The first sliding block 320 is movable in the machining feed direction indicated by the arrow X along the pair of guide rails 310 by fitting the pair of guided grooves 3210 into the pair of guide rails 310. The illustrated holding table mechanism 30 has a processing feed means 370 for moving the first sliding block 320 along the pair of guide rails 310 in the processing feed direction indicated by the arrow X. Processing feed means 370 includes a male threaded rod 3710. The male screw rod 3710 is installed between the pair of guide rails 310 and 310 in parallel with the guide rail 310. The processing feed means 370 further includes a drive source such as a pulse motor 3720 for driving the male screw rod 3710 to rotate. One end of the male screw rod 3710 is rotatably supported by a bearing block 3730 fixed to the stationary base 20. The other end of the male screw rod 3710 is connected to the output shaft of the pulse motor 3720. The male screw rod 3710 is screwed (fitted) into a through female screw hole of a female screw block (not shown) protruding from the lower surface of the central portion of the first sliding block 320. Therefore, the first slide block 320 can be moved along the pair of guide rails 310 in the processing feed direction indicated by the arrow X by driving the male screw rod 3710 forward or reversely by the pulse motor 3720.

  On the lower surface of the second sliding block 330, a pair of guided grooves 3310 that fits with the pair of guide rails 3220 provided on the upper surface of the first sliding block 320 are provided. By fitting the pair of guided grooves 3310 into the pair of guide rails 3220, the second sliding block 330 can move in the index feed direction indicated by the arrow Y. In addition, the illustrated holding table mechanism 30 includes a first index feeding means 380. The first index feed means 380 is a means for moving the second slide block 330 along the pair of guide rails 3220 provided in the first slide block 320 in the index feed direction indicated by the arrow Y. . The first index feed means 380 includes a male screw rod 3810. The male screw rod 3810 is disposed between the pair of guide rails 3220 and 3220 in parallel with the guide rail 3220. The first index feed means 380 further includes a driving source such as a pulse motor 3820 for driving the male screw rod 3810 to rotate. One end of the male screw rod 3810 is rotatably supported by a bearing block 3830 fixed to the upper surface of the first slide block 320. The other end of the male screw rod 3810 is connected to the output shaft of the pulse motor 3820. Further, the male screw rod 3810 is screwed (fitted) into a through female screw hole of a female screw block (not shown) protruding on the lower surface of the central portion of the second sliding block 330. Therefore, by driving the male screw rod 3810 forward or backward by the pulse motor 3820, the second sliding block 330 can move along the pair of guide rails 3220 in the index feed direction indicated by the arrow Y.

  The laser beam irradiation unit support mechanism 40 includes a guide rail 410 and a movable support base 420. The guide rails 410 are two (a pair) and are arranged on the stationary base 20 in parallel along the index feed direction indicated by the arrow Y. The movable support base 420 is disposed on the pair of guide rails 410 so as to be movable in the direction indicated by the arrow Y. The movable support base 420 includes a movement support portion 4210 that is movably disposed on the pair of guide rails 410, and a mounting portion 4220 that is attached to the movement support portion 4210. The mounting portion 4220 is provided with a pair of guide rails 4230 extending in the direction of condensing point position adjustment indicated by an arrow Z on one side surface in parallel with each other. The illustrated laser beam irradiation unit support mechanism 40 includes a second index feed means 430. The second index feed means 430 is a means for moving the movable support base 420 along the pair of guide rails 410 in the index feed direction indicated by the arrow Y. The second index feeding means 430 includes a male screw rod 4310. The male screw rod 4310 is disposed between the pair of guide rails 410 and 410 in parallel with the guide rail 410. The second index feed means 430 further includes a drive source such as a pulse motor 4320 for driving the male screw rod 4310 to rotate. One end of the male screw rod 4310 is rotatably supported by a bearing block (not shown) fixed to the stationary base 20. The other end of the male screw rod 4310 is connected to the output shaft of the pulse motor 4320. Further, the male screw rod 4310 is screwed (fitted) into a female screw hole of a female screw block (not shown) protruding from the lower surface of the central portion of the moving support portion 4210 constituting the movable support base 420. For this reason, the movable support base 420 can be moved along the pair of guide rails 410 in the index feed direction indicated by the arrow Y by driving the male screw rod 4310 forward or backward by the pulse motor 4320.

  The illustrated laser beam irradiation unit 50 includes a unit holder 510 and laser beam irradiation means 60 attached to the unit holder 510. The unit holder 510 is provided with a pair of guided grooves 5110 slidably fitted to a pair of guide rails 4230 provided in the mounting portion 4220. The pair of guided grooves 5110 are supported so as to be movable in the condensing point position adjustment direction indicated by the arrow Z by fitting into the pair of guide rails 4230. The laser beam irradiation means 60 is, for example, a group III-V compound seed crystal formation laser beam irradiation means (group III-V compound seed crystal formation means) in the seed crystal formation substrate manufacturing apparatus of the present invention, or III of the present invention. It can be used as a substrate separation laser beam irradiation means in a group V compound crystal manufacturing apparatus.

  The illustrated laser beam irradiation unit 50 includes a condensing point position adjusting unit 530. The condensing point position adjusting means 530 is a means for moving the unit holder 510 along the pair of guide rails 4230 in the condensing point position adjusting direction indicated by the arrow Z. The condensing point position adjusting means 530 includes a male screw rod (not shown) disposed between the pair of guide rails 4230 and a drive source such as a pulse motor 5320 for rotationally driving the male screw rod. The male screw rod (not shown) is driven to rotate normally or reversely by a pulse motor 5320, whereby the unit holder 510 and the laser beam irradiation means 60 are adjusted along the pair of guide rails 4230 as indicated by the arrow Z. It can move in the direction. In the illustrated embodiment, the laser beam irradiation means 60 can be moved upward by the forward rotation driving of the pulse motor 5320, and the laser light irradiation means 60 can be moved downward by the reverse rotation driving of the pulse motor 5320.

  The illustrated laser beam irradiation means 60 includes a cylindrical casing 610 disposed substantially horizontally. In the casing 610, a laser oscillator (laser light oscillation means, not shown) is arranged. This laser oscillator can emit laser light. Examples of the laser beam include a pulse laser beam and a CW laser beam, and a pulse laser beam is preferable. The laser oscillator is not particularly limited. For example, <1-1-2. Group III-V compound seed crystal forming step> or <1-3. Substrate separation step>. The wavelength, output, spot diameter, energy density, moving speed (feeding speed), frequency, pulse width, etc. of the laser light emitted from the laser oscillator are not particularly limited. For example, <1-1-2. Group III-V compound seed crystal forming step> or <1-3. Substrate separation step>. For example, when the laser beam is a pulsed laser beam used in the substrate separation step, the pulse width, as described above, narrows the region of the thermal decomposition reaction at the interface between the group III-V compound and the substrate, so that the peelability is good. In order to maintain the quality and maintain the quality by preventing excessive heat input to the compound substrate, the pulse width is preferably such that the thermal diffusion length is 200 nm or less, for example, 200 ps or less. The laser beam oscillated from the laser oscillator is processed by a work piece (for example, a III-V group compound layer laminated on a substrate) from a condenser 640 located at the tip of the casing 610 and held on a holding table 360. The laminated substrate or a laminate in which a group III-V compound crystal is laminated on the substrate) is irradiated. An imaging unit 90 is provided at the tip of the casing 610. The imaging unit 90 includes, for example, a normal imaging device (CCD) that captures an image with visible light, an infrared illumination unit that irradiates a workpiece with infrared rays, an optical system that captures infrared rays emitted by the infrared illumination unit, and the It includes an image sensor (infrared CCD) that outputs an electrical signal corresponding to the infrared rays captured by the optical system. The imaging unit 90 sends the captured image signal to a control unit (not shown).

  Next, an example of a laser processing method by the laser processing apparatus 10 in FIG. 5 will be described. This laser processing method is, for example, the above-mentioned III-V compound seed crystal forming step in the seed crystal production substrate manufacturing method or III-V compound crystal manufacturing method of the present invention, or the III-V group compound crystal of the present invention. It can be used in the substrate separation step in the manufacturing method. First, as shown in FIG. 6, a workpiece 400 (upper layer portion 200, lower layer portion 300) having two layers is pasted on an adhesive tape T mounted on an annular frame F (workpiece pasting step). At this time, the workpiece 400 is attached to the adhesive tape T with the front surface 200b up and the back surface 30b side. The adhesive tape T may be formed from a resin sheet such as polyvinyl chloride (PVC), for example. The annular frame F is installed on the holding table 360 shown in FIG. In the workpiece 400, for example, the upper layer portion 200 may be the substrate 11 of FIG. 1, and the lower layer portion 300 may be the III-V group compound layer 12 or the III-V group compound crystal of FIG. Conversely, the upper layer portion 200 may be the III-V group compound layer 12 or the III-V group compound crystal of FIG. 1, and the lower layer portion 300 may be the substrate 11 of FIG. That is, if necessary, the laser beam may be irradiated from either the substrate side or the III-V group compound layer side (or the III-V group compound crystal side).

  Next, the holding table 360 shown in FIG. 5 is moved to the laser light irradiation region where the condenser 640 of the laser light irradiation means 60 is located. Accordingly, as shown in the perspective view of FIG. 7 and the front view of FIG. 8A, the workpiece 400 is disposed below the condenser 640, and the workpiece 400 can be irradiated with the laser beam. For example, first, as shown in FIG. 8A, the end 230 (the left end in FIG. 8A) of the workpiece 400 is disposed directly below the light collector 640. Next, the condensing point P of the laser light emitted from the condenser 640 is matched with the vicinity of the surface 200b (upper surface) of the workpiece 400 as shown in FIG. Alternatively, as shown in the cross-sectional view of FIG. 8B, the laser beam is focused on the interface 30 a of the two-layer workpiece 400 including the upper layer portion 200 and the lower layer portion 300. Then, laser light is irradiated from the condenser 640 of the laser light irradiation means 60, the processing feed means 370 (FIG. 5) is operated, and the holding table 360 (FIG. 5) is indicated by an arrow X1 in FIG. It is moved in the direction at a predetermined processing feed rate. In addition, when the laser beam irradiated from the collector 640 is a pulse laser beam, it is preferable that the pulse width and the moving speed of the process feed means 370 are synchronizing. Accordingly, the pulse laser beam can be irradiated one shot at a high speed while switching the pulse laser beam on and off at a high speed. In this way, by irradiating a necessary portion of the workpiece 400 with laser light, for example, removal of a part of the III-V group compound layer in the III-V group compound seed crystal forming step, or A bond breaking step for breaking the bond with the substrate in the III-V compound crystal can be performed.

<3. III-V Group Compound Crystal, Semiconductor Device>
As described above, the III-V group compound crystal of the present invention is a group III-V compound crystal produced by the production method of the present invention, or a III-V having a dislocation density of 1 × 10 ² cm ⁻² or less. Group compound crystals. The Group III nitride crystal of the present invention is, for example, large in size and high quality with few defects. In the group III-V compound crystal produced by the production method of the present invention, the dislocation density is not particularly limited, but is preferably low, for example, 1 × 10 ² cm ⁻² or less. The dislocation density is preferably less than 1 × 10 ² cm ⁻² , more preferably 50 cm ⁻² or less, more preferably 30 cm ⁻² or less, still more preferably 10 cm ⁻² or less, and particularly preferably 5 cm ⁻² or less. is there. The lower limit value of the dislocation density is not particularly limited, but ideally is 0 or a value less than or equal to the measurement limit value by the measuring instrument. The value of the dislocation density may be, for example, the average value of the entire crystal, but is more preferable if the maximum value in the crystal is equal to or less than the value. Further, in the group III nitride crystal of the present invention, the half-value width of the reference reflection component (002) and the asymmetric reflection component (102) of the half-value width by XRC (X-ray rocking curve diffraction method) is not particularly limited, For example, it is 100 seconds or less, preferably 30 seconds or less. The lower limit value of the measured value of the XRC half width is not particularly limited, but ideally is 0 or a value less than or equal to the measurement limit value by the measuring device.

  The use of the group III nitride crystal of the present invention is not particularly limited. For example, the group III nitride crystal can be used for a semiconductor device due to its properties as a semiconductor. As described above, the semiconductor device of the present invention is a semiconductor device including the III-V group compound crystal of the present invention which is a semiconductor.

  The group III nitride crystal of the present invention can provide a very high-performance semiconductor device, for example, by being large in size and having few defects and high quality. In addition, according to the present invention, for example, as described above, it is also possible to provide a III-V group compound (for example, GaN) crystal having a diameter of 6 inches or more, which is impossible with the prior art. As a result, for example, in power devices and LEDs, which are based on the large diameter of Si (silicon), by using a III-V group compound in place of Si, higher performance can be achieved. is there. As a result, the impact of the present invention on the semiconductor industry is extremely large.

  Note that the semiconductor device of the present invention is not particularly limited, and any semiconductor device that operates using a semiconductor may be used. Examples of articles that operate using a semiconductor include a semiconductor element, an inverter, and the electric device using the semiconductor element and the inverter. The semiconductor device of the present invention may be various electric devices such as a mobile phone, a liquid crystal television, a lighting device, a power device, a laser diode, a solar cell, a high-frequency device, a display, or a semiconductor used for them. It may be an element, an inverter, or the like. Although the said semiconductor element is not specifically limited, For example, a laser diode (LD), a light emitting diode (LED), etc. are mentioned. For example, a laser diode (LD) that emits blue light is applied to a high-density optical disk, a display, and the like, and a light-emitting diode (LED) that emits blue light is applied to a display, illumination, and the like. Further, the ultraviolet LD is expected to be applied to biotechnology and the like, and the ultraviolet LED is expected to be an alternative ultraviolet source for the mercury lamp. Moreover, the inverter which used the III-V group compound of this invention as a power semiconductor for inverters can also be used for electric power generation, such as a solar cell, for example. Furthermore, as described above, the group III-V compound crystal of the present invention is not limited to these, and can be applied to other arbitrary semiconductor devices or other broad technical fields.

  Next, examples of the present invention will be described. However, the present invention is not limited to the following examples.

In the following examples and reference examples, the LPE apparatus having the structure shown in the schematic diagrams of FIGS. 16A and 16B was used for the production (growth) of crystals. As shown in FIG. 16A, this LPE apparatus includes a source gas tank 361 for supplying source gas (nitrogen gas in this embodiment), a pressure regulator 362 for adjusting the pressure of the growth atmosphere, and a leak A valve 363, a stainless steel container 364 for crystal growth, and an electric furnace 365. FIG. 16B is an enlarged view of the stainless steel container 364, and a crucible 366 is set inside the stainless steel container 364. In this example, all the crucibles made of aluminum oxide (Al ₂ O ₃ ) were used. In this example, Ga: Na represents a substance amount ratio (molar ratio) between gallium and sodium used. In addition, as a laser beam irradiation apparatus, DFL 7560 (trade name) manufactured by DISCO Corporation was used.

Example 1
First, a laminated substrate (manufactured by Furuuchi Chemical Co., Ltd., trade name GaN Template Type 10) in which a GaN layer having a thickness of about 8 μm was laminated on a 430 μm-thick sapphire substrate (0.18 × 0.12 cm) was prepared. Next, laser light irradiation is performed from the GaN layer side of the multilayer substrate under the conditions shown in Table 1 below, and a part of the GaN layer is removed to form a GaN seed crystal. A seed crystal forming substrate on which a plurality of the GaN seed crystals were formed was manufactured.
[Table 1]
Wavelength Output Frequency Spot diameter Feed rate
(Nm) (W) (kHz) (μm) (mm / s)
1030 15 200 50 200

  FIG. 9 shows the shape, size, and arrangement of the GaN crystal on the seed crystal formation substrate. That is, the GaN seed crystal was a square with a side of 0.5 mm, and as shown in FIG. 9A, each side was parallel and arranged to face each other at intervals of 0.5 mm. FIG. 9B shows a photograph of a part of the plurality of GaN crystals. FIG. 9 (c) shows an enlarged photograph of one GaN seed crystal in FIG. 9 (b). Further, FIGS. 9D to 9F show SEM (Scanning Electron Microscope) images. FIG. 9D is an SEM view of a part of the plurality of GaN crystals. FIG. 9 (e) is an enlarged SEM view of one GaN seed crystal in FIG. 9 (d). Further, FIG. 9 (f) is an enlarged SEM view of a part of the side of the GaN seed crystal in FIG. 9 (e). In FIG. 9, the GaN seed crystals adjacent to each other in the long side direction of the sapphire substrate are arranged so that the m axes overlap each other, and the GaN seed crystals adjacent to each other in the short side direction of the sapphire substrate Arranged to overlap.

Using this seed crystal formation substrate, crystal growth (growth) was performed under the following conditions in a nitrogen gas atmosphere to produce a GaN crystal. The following “C [mol%] 0.5” indicates that 0.5 mol% of carbon powder was added to the total amount of gallium (Ga), sodium (Na) and the carbon powder. In operation, first, the crucible 366 was placed in a stainless steel container 364, and the stainless steel container 364 was placed in an electric furnace (heat-resistant and pressure-resistant container) 365. Nitrogen gas is introduced into the stainless steel container 364 from the raw material gas tank 361 and simultaneously heated by a heater (not shown) in the electric furnace (heat-resistant pressure-resistant container) 365 as described in the following reaction condition 1 or reaction condition 2. Crystal growth (growth) was carried out by reacting for 96 hours under the above high temperature and high pressure conditions to produce the desired GaN crystal.

(Reaction condition 1)
Temperature [° C.] 870
Pressure [MPa] 4.0
Time [h] 96
Ga: Na 27:73
C [mol%] 0.5
Crucible Al ₂ O ₃

(Reaction condition 2)
Temperature [° C] 850
Pressure [MPa] 4.4
Time [h] 96
Ga: Na 27:73
C [mol%] 0.5
Crucible Al ₂ O ₃

Furthermore, after the GaN crystal is manufactured, laser light (pulse laser beam) is irradiated under the conditions shown in Table 2 below, and then the sapphire substrate is peeled from the GaN crystal, whereby the GaN crystal is removed from the sapphire substrate. Separated (substrate separation step). In addition, the GaN crystal manufactured in this example and other examples described later could be separated from the sapphire substrate by force without irradiating the laser beam. However, by peeling the sapphire substrate from the GaN crystal after laser light irradiation under the above conditions, the GaN crystal can be smoothly removed without damaging the interface between the GaN crystal and the substrate and the GaN crystal body. It was separated from the sapphire substrate.
[Table 2]
Wavelength Output Frequency Pulse width Spot diameter Feed rate
(Nm) (W) (Hz) (ns) (μm) (mm / s)
Condition 248 0.08 50 10 400 20

  The GaN crystal was manufactured several times under the above conditions. A photograph of the manufactured GaN crystal is shown in FIG. As shown in the figure, in any of FIGS. 10A to 10C, a high-quality GaN crystal having a large size and few defects could be manufactured. 10A is a crystal manufactured (grown) under the reaction condition 1, and FIGS. 10B and 10C are crystals manufactured (grown) under the reaction condition 2. is there.

(Reference example)
A GaN crystal was produced in the same manner as in Example 1 except that the shape, size, and arrangement of the GaN seed crystal were as shown in FIG. 11 (a) or (b). Note that “18 mm” and “12 mm” in FIG. 11A represent the major axis and the minor axis of the sapphire substrate, respectively. In the figure, “1.0 mm”, “0.5 mm”, and “0.25 mm” represent the diameter of each GaN seed crystal (circular). In the figure, the distance between the centers of adjacent GaN seed crystals is 4.5 mm. In FIG. 11B, as shown, the shape of the GaN seed crystal is a circle, a regular triangle or a regular hexagon, and the major axis is 0.5 mm. The distance between the centers of GaN crystals adjacent to each other was 5 mm.

  12 (a) to 12 (c) show enlarged SEM diagrams of the GaN seed crystals in FIG. 11 (b). As shown in the figure, a regular triangle, regular hexagon or circular shape can be clearly confirmed.

  FIG. 13 (a) shows a photograph of a GaN crystal grown from the GaN seed crystal of FIG. 11 (a). FIG. 13 (b) shows a photograph of a GaN crystal grown from the GaN seed crystal of FIG. 11 (b). In FIGS. 13A and 13B, the left-hand white portion schematically shows the shape, size, and arrangement of each GaN seed crystal. The right pyramid-shaped object is a GaN crystal grown from each GaN seed crystal. As shown in the figure, the size of the GaN crystal was different depending on the size of the GaN seed crystal, but a high quality GaN crystal with few defects was obtained from any GaN seed crystal. All GaN crystals had a hexagonal pyramid shape indicating hexagonal crystal.

  In addition, when the half width by XRC of the GaN crystal obtained (grown) by this reference example was measured at SPring-8 (a facility owned by RIKEN), 1.83 seconds (GaN ( 006) component) was obtained. Considering the spread of X-rays, it is said that the theoretical value of the full width at half maximum in a complete crystal of GaN (a crystal having no crystal defects) is 1.81 seconds (GaN (006) component). Therefore, considering the measurement error, the measured value of 1.83 seconds is considered to indicate that the crystal defect of the GaN crystal is 0 or almost 0.

(Example 2)
A GaN crystal was produced under the same reaction conditions 2 as in Example 1, and a CL (cathode luminescence) image was taken and the dislocation density was measured. Further, a GaN crystal was produced under the same conditions as those in the reaction condition 2 of Example 1 except that the length of one side was reduced to 0.25 mm without changing the center position of the GaN seed crystal, and its CL (cathode luminescence) was obtained. Sense) images were taken and the dislocation density was measured.

  14 and 15 show CL images of the GaN crystal. Both are CL images showing a longitudinal section after the GaN crystal is cut to a thickness of 2 mm in parallel with the sapphire substrate plane. FIG. 14 is a CL image when the diameter (length of one side) of the GaN seed crystal is 0.25 mm, and FIG. 15 is when the diameter (length of one side) of the GaN seed crystal is 0.5 mm. It is a CL image. As shown in FIG. 14, when the GaN seed crystal had a diameter of 0.25 mm, no dislocation dense region was observed in the CL image. Further, as shown in FIG. 15, when the diameter of the GaN seed crystal was 0.5 mm, no dark spots showing dislocations were observed in the CL image. As described above, the GaN crystal of FIGS. 14 and 15 is a crystal having a very small number of dislocations (that is, a dislocation density is extremely small), and it is difficult to observe the dislocation itself from the CL images of FIGS. Met. That is, as far as based on the CL images of FIGS. 14 and 15, the dislocation density observed in these GaN crystals was zero. 14 and 15 was measured at SPring-8 (a facility owned by RIKEN), the FWHM of the GaN crystal of FIGS. 14 and 15 was 1.83 seconds (like the GaN crystal of the reference example). A measured value of GaN (006) component was obtained. These measurement results show that the number of dislocations in the GaN crystal is extremely small (the dislocation density is extremely small) as compared with a general GaN crystal.

  As described above, according to the present invention, a high-quality III-V compound crystal manufacturing method, a seed crystal-forming substrate manufacturing method, a III-V compound crystal manufacturing apparatus, and a seed crystal formation that are large in size and have few defects. A substrate manufacturing apparatus can be provided. According to the present invention, for example, as described above, it is also possible to provide a III-V group compound (for example, GaN) crystal having a diameter of 6 inches or more, which is impossible with the prior art. The method for producing a group III-V compound crystal of the present invention and the use of the group III-V compound crystal produced thereby are not particularly limited, and as described above, can be applied to any semiconductor device or other wide technical fields. Is possible.

11 Substrate 12 III-V compound layer 12a III-V compound seed crystal 13 III-V compound crystal 14 Cut surface 15 Resist (etching mask)
17 Mask film 361 Source gas tank 362 Pressure regulator 363 Leak valve 364 Stainless steel vessel 365 Electric furnace 366 Crucible 10: Laser processing device 20: Stationary base 30: Holding table mechanism 320: First sliding block 330: Second sliding Block 370: Processing feed means 380: First index feed means 360: Holding table 3610: Holding member: Water supply means 40: Laser light irradiation unit support mechanism 420: Movable support base 430: Second index feed means 50: Laser light irradiation unit 510: Unit holder 60: Laser light irradiation means 640: Condenser 90: Imaging means 530: Condensing point position adjusting means 400: Work piece
F: Ring frame
T: Adhesive tape

Claims (25)

A seed crystal forming substrate providing step of providing a seed crystal forming substrate in which a plurality of group III-V compound seed crystals are formed on the substrate;
Contacting a surface of the plurality of group III-V compound seed crystals with a metal melt;
A crystal growth step in which a group III element and a group V element are reacted in the metal melt to generate and grow a group III-V compound crystal using the group III-V compound seed crystal as a nucleus,
In the crystal growth step, a plurality of III-V compound crystals grown from the plurality of III-V compound seed crystals are combined to grow a group III-V compound crystal. A manufacturing method comprising:
The plurality of group III-V compound seed crystals are group III-V compound seed crystals formed by physically removing a part of the group III-V compound layer formed on the substrate. Characterized by the
A method for producing a group III-V compound crystal. The group V element is nitrogen;
The metal melt is an alkali metal melt,
The group III-V compound is a group III nitride;
In the crystal growth step, a group III nitride crystal is formed using the group III-V compound seed crystal as a nucleus by reacting a group III element and the nitrogen in the alkali metal melt in an atmosphere containing nitrogen. The production method according to claim 1, wherein the production method is grown.   The manufacturing method according to claim 1, wherein the physical processing for removing a part of the III-V group compound layer to form the III-V group compound seed crystal is laser light irradiation.   The manufacturing method according to claim 3, wherein the wavelength of the laser beam is a wavelength that is absorbed by the III-V group compound layer and passes through the substrate.   The manufacturing method according to any one of claims 1 to 4, wherein a shape of the group III-V compound seed crystal is a dot shape, and a major axis of the dot is 1.0 mm or less.   The manufacturing method according to claim 5, wherein an interval between the III-V group compound seed crystals adjacent to each other is in a range of 0.1 to 1.0 mm.   The manufacturing method according to claim 1, wherein the group III-V compound seed crystal and the group III-V compound crystal are gallium nitride (GaN). It is a manufacturing method of the seed crystal formation board used for a manufacturing method of a III-V group compound crystal according to any one of claims 1 to 7,
A laminated substrate providing step of providing a laminated substrate in which a III-V group compound layer is laminated on the substrate;
And a III-V compound seed crystal forming step of forming a plurality of III-V compound seed crystals by removing a part of the III-V compound layer by physical processing. Method.   In the III-V group compound seed crystal forming step, the physical processing for forming a group III-V compound seed crystal by removing a part of the group III-V compound layer is performed by laser light irradiation. The manufacturing method according to claim 8.   The manufacturing method according to any one of claims 1 to 7, wherein the seed crystal forming substrate providing step includes a step of manufacturing the seed crystal forming substrate by the manufacturing method according to claim 8 or 9.   The manufacturing method according to any one of claims 1 to 7 and 10, further comprising a substrate separation step of separating the group III-V compound crystal from the substrate. The substrate separation step includes
A bond breaking step of breaking the bond between the III-V group compound crystal and the substrate by irradiating the III-V group compound crystal with laser light from the substrate side;
A substrate peeling step of peeling the substrate from the III-V group compound crystal,
The manufacturing method according to claim 11, wherein the wavelength of the laser beam is a wavelength that is absorbed by the III-V group compound layer and is transmitted through the substrate.   The manufacturing method according to claim 12, wherein a wavelength of the laser beam in the substrate separation step is longer than an absorption edge of the substrate and shorter than an absorption edge of the III-V group compound crystal. The substrate is a sapphire substrate;
The group III-V compound crystal is a GaN crystal, and
The manufacturing method according to claim 12 or 13, wherein a wavelength of the laser beam in the substrate separation step is in a range of 150 to 355 nm.   The manufacturing method according to claim 12, wherein the laser beam in the bond breaking step is a pulsed laser beam.   The manufacturing method according to claim 15, wherein the pulse width of the pulse laser beam is a pulse width at which a thermal diffusion length is 200 nm or less.   The manufacturing method according to claim 15 or 16, wherein a pulse width of the pulse laser beam is 200 ps (picosecond) or less.   The III-V group compound crystal manufactured by the manufacturing method as described in any one of Claim 1 to 7 and 10 to 17. A group III-V compound crystal having a dislocation density of 1 × 10 ² cm ⁻² or less.   20. A semiconductor device comprising a III-V group compound crystal according to claim 18 or 19, which is a semiconductor. It is a manufacturing apparatus used for the manufacturing method according to any one of claims 1 to 17,
A manufacturing apparatus comprising III-V compound seed crystal forming means for removing a part of the III-V group compound layer by physical processing to form the plurality of III-V compound seed crystals.   The manufacturing apparatus according to claim 21, wherein the manufacturing method is the manufacturing method according to claim 8. The manufacturing method according to claim 9,
The III-V compound seed crystal forming means forms the III-V compound seed crystal by removing part of the III-V compound layer by laser light irradiation. 23. The manufacturing apparatus according to claim 22, which is a laser beam irradiation means. The manufacturing method is a manufacturing method according to any one of claims 12 to 17,
The manufacturing apparatus according to claim 21, further comprising a substrate separating laser light irradiation unit that irradiates the III-V group compound crystal with laser light from the substrate side in the substrate separating step. The manufacturing method is the manufacturing method according to any one of claims 15 to 17,
The manufacturing apparatus according to claim 24, wherein the substrate separation laser light irradiation means is a means for irradiating the pulse laser beam according to any one of claims 15 to 17.