JP2013100208A - Selection method of member used for manufacturing periodic table group 13 metal nitride semiconductor crystal, and manufacturing method of periodic table group 13 metal nitride semiconductor crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to accurately and conveniently select members of a reaction vessel, a stirring blade, a seed crystal holding rod, a seed crystal holding table, a baffle, a gas introduction pipe, a valve or the like that can be used for manufacturing a periodic table group 13 metal nitride semiconductor crystal, and to provide a manufacturing method of the periodic table group 13 metal nitride semiconductor crystal in which an adverse effect is not caused by the change in quality and/or the deterioration of the members.SOLUTION: The volume and/or the size of the member is measured, the volume change and/or the dimensional change from the unused state is made an indicator, and the member used for the manufacturing of the periodic table group 13 metal nitride semiconductor crystal is selected, thereby the member not to affect the crystal growth negatively can be selected accurately and simply. The influence that incorporates hydrogen is large for the expansion of the member, thereby the selection method of the member is especially suitable for the manufacturing method in which the component including a hydrogen element exists in a reaction system.

Description

  The present invention relates to a method for selecting a member used for manufacturing a periodic table group 13 metal nitride semiconductor crystal and a method for manufacturing a periodic table group 13 metal nitride semiconductor crystal.

  Periodic table Group 13 metal nitride semiconductors typified by gallium nitride have a large band gap, and the transition between bands is a direct transition type. It has been put to practical use as a light emitting element on the short wavelength side. These elements are preferably manufactured using a high-quality substrate made of the same kind of material and having a low dislocation density, and a manufacturing technique of a periodic table group 13 metal nitride semiconductor crystal that can be such a substrate is used. It has been actively studied. As typical production methods, vapor phase epitaxial growth methods such as halide vapor phase epitaxy (HVPE) and metal organic chemical vapor deposition (MOCVD) are generally known. From the above viewpoint, etc., studies on a liquid phase epitaxial growth method such as a sodium flux method are also in progress.

  Regarding liquid phase epitaxial growth methods such as the sodium flux method, the problem that reaction vessels used for production swell, infiltrate and deteriorate has been reported, and ceramics made of titanium nitride or zirconium nitride have been reported as a method for solving such problems. It has been proposed to use a manufactured reaction vessel (see Patent Document 1). In addition, since a ceramic reaction vessel is inferior in workability and mechanical durability, a metal member containing a Group 4-6 element in the periodic table with a nitride layer formed on the surface (reaction vessel, stirring blade, seed) It has been proposed to use a crystal holding rod, a seed crystal holding table, a baffle, a gas introduction pipe and a valve (see Patent Document 2). It has been reported that the use of such a member having excellent corrosion resistance and workability can greatly reduce the manufacturing cost.

JP 2006-265069 A International Publication No. 2010/140665

A material excellent in corrosion resistance is selected as a member such as a reaction vessel used for the production of the Group 13 metal nitride semiconductor crystal of the periodic table, but deterioration and / or deterioration progresses by repeated and / or long-time use. There are things to do. If a member that has reached such a state is used in the manufacture of semiconductor crystals, it may adversely affect crystal growth. Therefore, it is necessary to determine whether or not the member can be used before use. Although it is possible to grasp the state of alteration and / or deterioration by analyzing the member precisely, if the operation becomes complicated, it is not preferable from the viewpoint of efficiency and cost, but if it is not possible to accurately determine whether it can be used, This adversely affects the production of nitride semiconductor crystals.
That is, the present invention provides a method for accurately and simply selecting a member that can be used in the manufacture of a periodic table group 13 metal nitride semiconductor crystal, and a periodic table that is not adversely affected by alteration and / or deterioration of the member. It is an object of the present invention to provide a method for producing a group metal nitride semiconductor crystal.

As a result of intensive studies to solve the above problems, the present inventors have repeatedly and / or used for a long time in the production of Group 13 metal nitride semiconductor crystals of the periodic table. It has been clarified that the growth rate of the group 13 metal nitride semiconductor crystal of the periodic table is remarkably reduced when the crystal growth is performed using the member expanded to a specific size. Further, when used in a production method in which a component containing a hydrogen element (H ₂ , NH ₃ , CH _4, etc.) is present in the reaction system, it has been clarified that the member particularly takes in hydrogen and expands. Based on these findings, the present inventors have conducted further intensive studies. As a result, by observing the expansion coefficient of the member, it has been found that a member that may adversely affect crystal growth can be grasped. A method for selecting members to be used in the manufacture of Group III nitride semiconductor crystals was established.

That is, the present invention is as follows.
(1) A method for selecting a member to be used for producing a Group 13 metal nitride semiconductor crystal of the periodic table, wherein the volume and / or dimension of the member is measured, and the volume change and / or dimension from an unused state. A member selecting method, wherein the member is selected using a change as an index.
(2) The member selection method according to (1), wherein a member having a maximum dimensional change rate from an unused state is 0.8% or less.
(3) The method for selecting a member according to (1) or (2), wherein a member whose volume change rate from an unused state is 2.4% or less is selected.
(4) The method for selecting a member according to any one of (1) to (3), wherein the member includes at least one selected from Group 4 to 6 elements of the periodic table, Sc, Y, Ni, and Pd.
(5) The member is composed of 90% by weight or more of a metal or alloy containing at least one selected from Group 4 to 6 elements of the periodic table, Sc, Y, Ni and Pd. (1 The method for selecting a member according to any one of (4) to (4).
(6) The member according to any one of (1) to (5), wherein the member is formed with a nitride containing at least one selected from Group 4 to 6 elements of the periodic table on the surface. Selection method.
(7) The member according to any one of (1) to (6), wherein the production of the Group 13 metal nitride semiconductor crystal of the periodic table is a production method in which a component containing a hydrogen element is present in the reaction system. Selection method.
(8) In any one of (1) to (7), the member is at least one selected from a reaction vessel, a stirring blade, a seed crystal holding rod, a seed crystal holding table, a baffle, a gas introduction pipe, and a valve. The method for selecting the described member.
(9) A selecting step for selecting a member by the method for selecting a member according to any one of (1) to (8), a step for preparing a solution or melt containing a raw material and a solvent, and the solution or melt A method for producing a periodic table group 13 metal nitride semiconductor crystal comprising a growth step of epitaxially growing a periodic table group 13 metal nitride semiconductor crystal, wherein the step of producing the melt or solution and / or the growth step comprises The method for producing a periodic table group 13 metal nitride semiconductor crystal, which is performed using the member selected in the selection step and / or an apparatus including the member.
(10) The method for producing a periodic table group 13 metal nitride semiconductor crystal according to (9), wherein the growth step includes a component containing a hydrogen element in the reaction system.

  According to the present invention, a member that can be used in the production of a periodic table group 13 metal nitride semiconductor crystal can be selected accurately and simply, and in addition, the periodicity is not adversely affected by deterioration and / or deterioration of the member. Table 13 Group 13 metal nitride semiconductor crystals can be manufactured.

It is a conceptual diagram of the apparatus which nitrides the member surface. It is a conceptual diagram of the apparatus used for the manufacturing method of the periodic table group 13 metal nitride semiconductor crystal of this invention.

The method for selecting members used for the production of the Group 13 metal nitride semiconductor crystal of the periodic table and the method for producing the Group 13 metal nitride semiconductor crystal of the periodic table will be described in detail below. Unless it is contrary, it is not limited to these contents.

<Selection method of member used for production of periodic table group 13 metal nitride semiconductor crystal>
The present invention relates to a member used for manufacturing a periodic table group 13 metal nitride semiconductor crystal (hereinafter sometimes referred to as “group 13 nitride semiconductor crystal”), which does not adversely affect crystal growth. This is the method of selection. The present inventors repeatedly expand and / or use the group 13 nitride semiconductor crystal for a long time, so that the member expands cumulatively (not a temporary expansion due to heating or the like, but an observation in a room temperature state). It has been found that the growth rate of the group 13 nitride semiconductor crystal is remarkably reduced when crystal growth is performed using a member expanded to a specific size. Although such a principle has not been fully clarified, when the member absorbs the components present in the reaction system and expands and expands to a certain level or more, impurities are easily released from the member. This is probably because crystal growth is inhibited. The component absorbed by the member differs depending on the material of the member and the manufacturing method of the Group 13 nitride semiconductor crystal, but the production includes a component containing hydrogen element (H ₂ , NH ₃ , CH _4, etc.) in the reaction system. When used in the method, it was found that mainly hydrogen was taken up.
The expansion of the member, that is, the volume change, can be easily calculated by measuring the volume of the unused member in advance, compared with the measurement result at the time of selection. Therefore, in selecting a member, it is possible to easily determine a member that does not adversely affect crystal growth by observing the volume change of the member and using this result as an index.

The present invention is a method for selecting a member to be used for manufacturing a group 13 nitride semiconductor crystal, but the method for manufacturing a group 13 nitride semiconductor crystal targeted by the present invention is not particularly limited, and halide vapor phase growth is possible. For any growth method such as vapor phase epitaxy such as metal organic chemical vapor deposition (MOCVD) or liquid phase epitaxy such as melt growth, high pressure solution method, flux method, and low temperature method Is applicable. However, as described above, since the influence of taking in hydrogen is large with respect to the expansion of the member, it is particularly suitable for a production method in which a component containing a hydrogen element exists in the reaction system. Examples of the “component containing hydrogen element” include H ₂ , NH ₃ , hydrocarbons such as CH ₄ , C ₂ H ₆ , C ₃ H ₈ , hydrogen halides such as HF, HCl, HBr, HI, etc. Is mentioned. In particular, when used in a liquid phase epitaxial growth method containing H ₂ in the reaction system, the selection method of the present invention can be suitably used. Further, the type of the Group 13 nitride semiconductor crystal to be manufactured is not particularly limited, and in addition to a nitride composed of one type of Group 13 metal such as GaN, AlN, InN, two or more types of GaInN, GaAlN, etc. Examples include composite nitrides made of Group 13 metals.

The present invention is characterized in that a volume change and / or a dimensional change from an unused state is used as an index in order to select a member to be used for manufacturing a Group 13 nitride semiconductor crystal. As described above, the present inventors have found that a member expands cumulatively when used repeatedly and / or for a long time in the production of a group 13 nitride semiconductor crystal, and further expands to a specific size. It has been found that the crystal growth rate is remarkably reduced when crystal growth is carried out by using. That is, by observing the expansion coefficient of the member, it is possible to grasp a member that may adversely affect the crystal growth. Since the expansion coefficient can be grasped by measuring the volume change or dimensional change of the member, these values can be used as an index for selecting the member. Volume change (dimension change) is selected by measuring in advance the volume (dimension) of a member that is not used for manufacturing the Group 13 nitride semiconductor crystal (hereinafter also referred to as “unused state”). It can be easily calculated by comparing with the volume (dimension) sometimes measured. Moreover, when the volume (dimension) of the member in an unused state is not measured, it may be calculated using the value of the volume (dimension) in a state where it is clear that the member is not expanded. . The volume change (dimension change) is not particularly limited as long as it is a value representing a quantitative change of the volume (dimension), and is calculated by the difference between the volume (dimension) at the time of selection and the volume (dimension) in an unused state. In addition to the volume change amount (dimensional change amount), the volume change rate (dimensional change rate) calculated by the following equations [1] and [2] may be used. Moreover, the value processed by the desired calculation method may be sufficient if it represents the quantitative change of a volume (dimension).

The selection method of the present invention may use either volume change or dimensional change as an index, or may use both volume change and dimensional change as an index. You can choose. For example, when the shape of the member to be measured is complex or when the expansion of the member is very small, it is preferable to use the volume change as an index, while when the volume measurement is difficult or the expansion is partially When it occurs locally, it is preferable to use a dimensional change as an index. In particular, when the shape of the member to be measured is not complicated, for example, when it is a simple shape such as a rectangular parallelepiped, a cube, or a cylinder, there may be a certain correlation between the volume change rate and the dimensional change rate. is there. Specifically, assuming that the member to be measured is a cube and expands by the same amount on each side, when the dimensional change rate of one side is 0.5%, the volume change rate of the member is expressed by the equation [1. ], It can be calculated as {(1 + 0.5 × 0.01) ³ −1 ³ } / 1 ³ × 100≈1.5%.

  There are no particular restrictions on the types of dimensions when measuring dimensional changes. In addition to values such as the length, width, and height of a member, in the case of a member having a cylindrical shape, the inner diameter, outer diameter, and depth Etc. can also be used. The number of dimensions to be measured is not limited to one, and a plurality of kinds of dimensions may be measured, and those values may be used as appropriate. From the viewpoint of measurement accuracy and simplicity, it is preferable to select a representative dimensional change and use the value as an index, and it is more preferable to use a dimension that maximizes the dimensional change rate. In the present invention, the dimensional change rate at the dimension at which the dimensional change rate is maximum is referred to as “maximum value of dimensional change rate”. More preferably, this maximum value is used as an index.

  As a method for measuring the volume (dimension), a known method can be used as appropriate. Specifically, a method for measuring a dimension using a ruler, a measure, a caliper, or the like, or a method for measuring using a laser displacement meter And a method of measuring using an image capturing / image processing apparatus, a method of measuring using an Archimedes method of measuring a removal volume of a liquid when an object to be measured is put in a liquid such as water, and the like.

Specifically, the phrase “volume change and / or dimensional change is used as an index” means that a criterion for comparison with a measured value of volume change and / or dimensional change is set in advance, and the measured value is determined from the criterion. Is larger, it is determined that the member is not used, and in other cases, it is determined that the member may be used. The determination criteria used for the determination can be appropriately set according to the type of member, the type of material, the manufacturing method of the group 13 nitride semiconductor crystal, and the like. For example, the volume change and / or dimensional change of a member used for the production of a group 13 nitride semiconductor crystal is measured, and the crystal growth rate when the member is used is further calculated to determine the volume change and / or dimensional change. By finding the relationship between the crystal growth rate and the crystal growth rate, it is possible to derive a numerical value as a criterion. Although the specific criterion is not particularly limited, when the volume change rate is used, it is usually 2.4% or less, preferably 1.2% or less. Moreover, although a minimum is not specifically limited, Usually, setting it as 0.0% or more is mentioned. When the maximum value of the dimensional change rate is used, the criterion is usually 0.8% or less, preferably 0.4% or less. Moreover, although a minimum is not specifically limited, Usually, setting it as 0.0% or more is mentioned. When crystal growth is performed using a member exceeding the upper limit, the crystal growth rate tends to be slow. The smaller the criterion value, the lower the risk of selecting a member that cannot be used for crystal growth. However, if the criterion value is too small, the member that should originally be usable for crystal growth is determined to be unusable. This may cause the cost of the member at the time of manufacture.

  The present invention is a method for selecting a member characterized by using a volume change and / or a dimensional change from an unused state as an index. The “use” in the present invention is a group 13 nitride semiconductor crystal. In addition to the case where the member is actually used in the manufacture of the above, even if the condition does not lead to crystal growth, if the member is exposed to the atmospheric gas, melt or solution in crystal growth, Members are included as “used”. As described above, it is considered that the member expands by absorbing a component present in the reaction system. Therefore, the component may be absorbed by exposure to an atmospheric gas, a melt or a solution. There is. Note that the step of nitriding a member to be described later is not included in the “use”.

  The member targeted by the selection method of the present invention is not particularly limited as long as it is used for the production of a Group 13 nitride semiconductor crystal, but is exposed to an atmospheric gas, a solution, a melt, or the like in the crystal growth process. Possible members can be mentioned. Specifically, a reaction vessel, a stirring blade, a seed crystal holding rod, a seed crystal holding table, a baffle, a gas introduction pipe, a valve, and the like can be given.

The material of the member targeted by the selection method of the present invention is not particularly limited as long as it can be used for the production of a Group 13 nitride semiconductor crystal. However, as described above, the member may expand by taking in hydrogen. Therefore, it has a high affinity with hydrogen and is particularly suitable for a member containing a metal element that can form a hydride. Specifically, a member containing at least one selected from Group 4 to 6 elements of the periodic table (Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W), Sc, Y, Ni, Pd. Can be mentioned. Among them, a member containing an element whose standard generation energy ΔG ^f _{0 of the} hydride is less than 0 is preferable. In particular, Ti and Zr have standard generation free energies ΔG ^f ₀ of their hydrides of −80.3 kJ / mol and −128.8 kJ / mol, respectively, and have a particularly high affinity with hydrogen. Is particularly suitable.

Moreover, as a member used for manufacture of a group 13 nitride semiconductor crystal, it is preferable that it is a material rich in workability and mechanical durability, and a member is mainly comprised with the metal (bulk body). More preferred. Specifically, 90% by weight or more, more preferably 99% by weight or more of the member is made of a metal or alloy containing at least one selected from Group 4 to 6 elements of the periodic table, Sc, Y, Ni, Pd. More preferably. Further, the member may contain an oxide, nitride, carbide, or the like in addition to the metal or alloy. In particular, Group 4 to 6 elements of the periodic table have a standard free energy of formation ΔG ^f ₀ of nitride of less than 0, and form a stable nitride. By forming such a nitride layer on the surface, durability suitable for the manufacture of a Group 13 nitride semiconductor crystal can be obtained. Therefore, the member targeted by the present invention preferably contains a nitride containing at least one selected from Group 4 to 6 elements of the periodic table, and particularly has a nitride layer formed on the surface. preferable. The thickness of the nitride layer is not particularly limited, but is usually about 10 nm to 1 mm, preferably 100 nm to 100 μm, more preferably 1 μm to 10 μm.

When the member used for manufacturing the Group 13 nitride semiconductor crystal is a member having a nitride layer formed on the surface, the method of forming the nitride layer is not particularly limited, but the PVD method (Physical Vapor Deposition) And a method of laminating a nitride layer by a vapor deposition method such as a CVD method (Chemical Vapor Deposition), a method of separately producing a nitride, and laminating it on the surface of a member, and the like. Another example is a method of forming a nitride layer by nitriding the composition of the member surface itself. Among these, since the shape of the member is not limited and the nitride layer can be formed relatively easily, a method of forming the nitride layer by nitriding the composition of the member surface itself is more preferable.

The method of nitriding the composition of the member surface itself is not particularly limited as long as the nitride layer is stably formed on the surface. For example, heating is performed in a nitrogen atmosphere at 100 to 1500 ° C., preferably 700 ° C. or higher. By holding, a stable nitride layer can be formed. It is also possible to perform nitriding using an alkali metal nitride, alkaline earth metal nitride or the like as a nitriding agent, for example, usually in the presence of a nitriding agent, 200 to 1500 ° C., preferably 600 to 800. A stable nitride layer can be formed by heating and holding the member at a temperature of ° C. In the case of a nitrogen atmosphere, it is more preferable to circulate N ₂ gas in an amount converted to normal temperature and normal pressure, preferably 1 to 10000 cm ³ / min and 10 to 1000 cm ³ / min.

  The present invention is a method for selecting a member to be used for manufacturing a periodic table group 13 metal nitride semiconductor crystal. “A method for determining the replacement time of a member to be used for manufacturing a periodic table group 13 metal nitride semiconductor crystal” Or “a method for determining whether to continue using the group 13 metal nitride semiconductor crystal in the periodic table” is synonymous with the selection method of the present invention, and is included in the present invention.

<Method for Producing Periodic Table Group 13 Metal Nitride Semiconductor Crystal of the Present Invention>
According to the member selection method of the present invention, a member that does not adversely affect crystal growth can be selected accurately and simply, but the member selected by such a selection method and / or an apparatus including the selected member is used. A manufacturing method for manufacturing a Group 13 nitride semiconductor crystal is also one aspect of the present invention. Specifically, it is a manufacturing method that includes the method for selecting a member of the present invention as a selection step, and manufactures a Group 13 nitride semiconductor crystal using a liquid phase epitaxy (Liquid Phase Epitaxy). In the liquid phase epitaxial growth method, the member is easily deteriorated and / or deteriorated through the liquid phase, and the crystal growth is likely to be adversely affected. By including the method for selecting a member of the present invention as a process, it is possible to accurately and easily determine whether or not the member can be used, and it can be said that this is an efficient method for producing a Group 13 nitride semiconductor crystal. Hereinafter, the method for producing a Group 13 nitride semiconductor crystal of the present invention will be described in detail.

The method for producing a group 13 nitride semiconductor crystal of the present invention includes the following steps.
(1) Selection process for selecting members to be used for manufacturing (2) Process for producing solution or melt containing raw materials and solvent (3) Epitaxial growth of Group 13 metal nitride semiconductor crystals in the periodic table in solution or melt Growth process

  (1) The selection process of selecting a member to be used for manufacturing is the above-described method for selecting a member of the present invention. This step is a step for selecting a member that may be incorporated into a member or an apparatus that can be used in the step (2) for producing the melt or solution and the growth step (3).

(2) The step of preparing a solution or melt containing a raw material and a solvent means a step of preparing a solution or melt for liquid phase used for epitaxial growth as a pre-stage of the growth step, and (3) solution Alternatively, the growth step of epitaxially growing the periodic table group 13 metal nitride semiconductor crystal in the melt means a growth step using a liquid phase epitaxial growth method. Specifically, the growth process using the liquid phase epitaxial method includes a temperature difference (Gradient Transport) method, a slow cooling method, a temperature cycling method, which are mainly used in the flux method, Crucible Acceleration Rotation (Accelerated Crucible Rotation Technique) method, Top-Seeded Solution Growth
) Method, solvent transfer method and solvent-transfer floating-zone method, which is a variation thereof, and evaporation method, and a method in which these methods are arbitrarily combined. The details of these steps are not particularly limited and can be carried out by appropriately adopting known conditions, but the reaction vessel, stirring blade, seed crystal holding rod, seed crystal holding table, baffle, used in these steps, Regarding the members such as the gas introduction pipe and the valve, the members selected in the member selection step (1) are used. The member selecting step (1) can select a member that does not adversely affect the crystal growth, and is efficient as a method for manufacturing a Group 13 nitride semiconductor crystal. The solution or melt containing the raw material and the solvent does not need to be completely dissolved in the solvent, and may be a heterogeneous system in which the solid raw material is dispersed or present in the solution as a solid. In addition, the “liquid phase that is a solution or melt” in the growth step is not necessarily intended to be the same as the “solution or melt” in the step of producing the solution or melt. The “solution or melt” in the process of preparing the solution or melt is prepared for use in the growth process, but the “solution or melt” in the growth process includes a by-product generated by the reaction of epitaxial growth. This is because the composition may not be the same as the initial composition (before the start of epitaxial growth).

  The manufacturing method of the present invention is not particularly limited as long as it is a Group 13 nitride semiconductor crystal manufacturing method including a member selection method as a step, but as described above, in the reaction system, This is particularly effective in a manufacturing method having such a condition because the member may take in hydrogen and expand under conditions where a component containing a hydrogen element is present in the material, and may adversely affect crystal growth. Below, the manufacturing method of the liquid phase epitaxial method in which hydrogen exists in a reaction system is mentioned as an example.

FIG. 2 is a conceptual diagram of a production apparatus used in a production method of a liquid phase epitaxial method in which hydrogen is present in the reaction system. In FIG. 2, 104 represents a reaction vessel, 101 represents a Li ₃ GaN ₂ composite nitride (solid) as a raw material, 102 represents a LiCl molten salt as a solvent, and 100 represents a gallium nitride crystal as a seed crystal. Such a production method is characterized in that hydrogen is contained in the gas phase, and crystal growth is performed using hydrogen (nitrogen is also contained in the gas phase).
In the growth process of such a manufacturing method, Li ₃ GaN ₂ composite nitride in a liquid phase (Li ₃ GaN ₂ composite nitride is considered to form a complex salt with LiCl and dissolve), and a seed crystal also exists in the liquid phase. It reaches the surface and undergoes the reaction shown in the following reaction formula [3], and crystal growth proceeds.

In addition, hydrogen and nitrogen in the gas phase are dissolved directly or in the liquid phase to hydrogenate and / or nitride the Li ₃ N produced by the above formula [3], thereby lithium hydride, lithium imide, or lithium An amide is formed. For example, lithium amide (LiNH ₂ ) is produced by a reaction represented by the following formula [4]. An increase in the Li ₃ N concentration in the vicinity of the gallium nitride crystal causes a decrease in the growth rate, and an abrupt decrease in the Li ₃ N concentration also leads to rapid GaN formation, leading to the generation of miscellaneous crystals and a decrease in crystallinity. Hydrogen and nitrogen play a role in appropriately controlling the growth rate, and are particularly important for obtaining a semiconductor crystal having high crystallinity. Note that the reactions that generate lithium hydride, lithium imide, and lithium amide are all equilibrium reactions, and Li ₃ N depends on the concentration of hydrogen and nitrogen.
The concentration can be adjusted.

[material]
The raw material used in the production method of the present invention can be appropriately set according to the target group 13 nitride semiconductor crystal. For example, as in the above-described Li ₃ GaN ₂ composite nitride, A compound nitride containing a Group 13 metal and a Group 1 metal and / or a Group 2 metal of the periodic table can be exemplified as a preferable example. In addition to Ga, Group 13 metals include Al, In, GaAl, GaIn, etc., and Group 1 metals and / or Group 2 metals include Na, Ca, Sr, Ba, Mg, etc., in addition to Li. Can be mentioned. As a composite nitride containing a Group 13 metal and a Group 1 metal and / or a Group 2 metal, in addition to Li ₃ GaN ₂ , Ca ₃ Ga ₂ N ₄ , B
a ₃ Ga ₂ N ₄ , Mg ₃ GaN _{3 and the} like. Group 13 metal and Group 1 metal and / or second
The compound nitride containing a group metal is, for example, a mixture of a group 13 metal nitride powder and a group 1 metal and / or a group 2 metal nitride powder (for example, Li ₃ N, Ca ₃ N ₂ ). After that, adjusting the temperature by raising the temperature and causing a solid phase reaction; preparing an alloy containing a Group 13 element and a Group 1 metal and / or Group 2 metal and heating in a nitrogen atmosphere; Can do. For example, Li ₃ GaN ₂ can be manufactured by heat-treating a Ga—Li alloy at 600 to 800 ° C. in a nitrogen atmosphere.

  As a raw material other than the composite nitride containing the Group 13 metal and the Group 1 metal and / or the Group 2 metal, the Group 13 metal nitride itself can be used. In addition, for example, a mixed nitride film synthesized by reacting with nitrogen plasma by a reactive sputtering method using a target made of an alloy of a Group 13 metal and a Group 1 metal and / or a Group 2 metal may be mentioned. it can. Such a mixed nitride film is suitable when a nitride that is difficult to synthesize chemically is used.

  When the raw material is a solid under the conditions in the growth process, such a solid raw material need not be completely dissolved in the solvent. Even when a part is not dissolved but is present in the reaction vessel, the amount consumed by crystal growth is supplied to the solvent as needed. Further, the amount of the raw material with respect to the solvent is not particularly limited and can be appropriately set according to the purpose, but if it is within the range of 5 to 50% by weight, the efficiency for continuous production can be improved. Space in the reaction vessel can be secured.

[solvent]
Although the solvent used for the manufacturing method of this invention is not specifically limited, The solvent which has a metal salt as a main component is preferable. The content of the metal salt is preferably 50% by weight or more, more preferably 70% by weight or more, and still more preferably 90% by weight or more. In particular, a molten salt obtained by melting a metal salt is preferably used as a solvent.

The type of the metal salt is not particularly limited as long as it does not inhibit crystal growth, but alkali metal such as Li, Na, K and / or alkaline earth metal halide such as Mg, Ca, Sr, carbonate, Examples thereof include nitrates and sulfurates. _{Specifically, LiCl, KCl, NaCl, CaCl} 2, BaCl 2, CsCl, LiBr, KBr, CsBr, LiF, KF, NaF, LiI, NaI, metal halides such as CaI _2, BaI ₂ preferably, LiCl, KCl, NaCl, CsCl, CaCl ₂ and BaCl ₂ are more preferable. The type of metal salt is not limited to one type, and a plurality of types of metal salts may be used in appropriate combination. Among these, it is more preferable to use lithium halide and a metal salt other than this together. The content of lithium halide is preferably 30% or more, more preferably 80% or more, based on the total amount of the metal salt.

In order to increase the solubility of a composite nitride containing a Group 13 metal and a Group 1 metal and / or a Group 2 metal, for example, Li ₃ N, Ca ₃ N ₂ , Mg ₃ N ₂ , Sr ₃ it is preferable that N _2, Ba ₃ N ₂ group 1 metal or a nitride of group 2 metals, such as such are included in the solvent.

Metal salts generally have a high hygroscopic property and therefore contain a large amount of moisture. First periodic table of the present invention
In order to produce a Group 3 metal nitride semiconductor crystal, it is necessary to remove impurities that can be an oxygen source such as moisture as much as possible, that is, it is preferable to purify the solvent in advance. Although the purification method is not particularly limited, for example, a method in which a reactive gas is blown into a solvent using an apparatus described in JP-A-2007-084422 can be mentioned. For example, when a metal salt that is solid at room temperature is used as a solvent, it is melted by heating to hydrogen chloride, hydrogen iodide, hydrogen bromide, ammonium chloride, ammonium bromide, ammonium iodide, chlorine, bromine, or iodine. Impurities such as moisture can be removed by bubbling with a reactive gas such as. It is particularly preferable to use hydrogen chloride for the molten salt of chloride.

[Seed crystal (underlying substrate)]
In order to obtain an industrially sufficient crystal, it is preferable to install a seed crystal in the liquid phase in which the epitaxial growth proceeds. The seed crystal is the same type as the target group 13 nitride semiconductor crystal such as GaN, InGaN, AlGaN, etc., metal oxide such as sapphire, ZnO, BeO, silicon-containing material such as SiC, Si, or GaAs or the like can be used. Considering the consistency with the Group 13 nitride semiconductor crystal grown in the present invention, the Group 13 nitride is most preferable. The shape of the seed crystal is not particularly limited, and may be a flat plate shape or a rod shape. In the case of using a rod-shaped seed crystal, it is possible to produce a bulk crystal by first growing in the seed crystal portion and then performing crystal growth in the vertical direction while also performing crystal growth in the horizontal direction. In order to efficiently grow the group 13 nitride crystal on the seed crystal, it is preferable that no miscellaneous crystal is grown or attached around the seed crystal. A miscellaneous crystal is a crystal having a small particle diameter that grows other than on the seed crystal. When the miscellaneous crystal exists near the seed crystal, the group 13 nitride component in the liquid phase is grown on the seed crystal and the growth of the miscellaneous crystal. As a result, the growth rate of the group 13 nitride semiconductor crystal on the seed crystal cannot be sufficiently obtained.

[Temperature, pressure and other conditions]
In the growth step, the growth temperature for growing the Group 13 nitride semiconductor crystal in the reaction vessel is usually 200 ° C. or higher, preferably 400 ° C. or higher, more preferably 600 ° C. or higher, and usually 1000 ° C. Hereinafter, it is preferably 850 ° C. or lower, more preferably 800 ° C. or lower. Further, in the growth step, the pressure in the reaction vessel for growing the group 13 nitride semiconductor crystal can be appropriately selected depending on the conditions and is not particularly limited. However, the production apparatus becomes simple and industrially advantageous. Since it can be produced, it is usually 10 MPa or less, preferably 3 MPa or less, more preferably 0.3 MPa or less, more preferably 0.11 MPa or less, and usually 0.01 MPa or more, preferably 0.09 MPa or more.

  The hydrogen in the growth step may be sequentially supplied into the gas phase or a necessary amount may be prepared in the reaction vessel in advance, but it is preferable to supply it sequentially into the gas phase. The flow rate of the hydrogen gas is usually 0.0001 to 10 L / min, preferably 0.001 to 5 L / min, more preferably 0.01 to 1 L / min, in an amount converted to normal temperature and normal pressure. Within the above range, the concentration of by-products can be kept moderate. The hydrogen concentration in the gas phase is usually 0.001 to 99.9 mol%, preferably 0.1 to 99 mol%, more preferably 1 to 90 mol%.

  Nitrogen in the growth step may be sequentially supplied into the gas phase or a necessary amount may be prepared in advance in the reaction vessel. However, it is preferable to supply nitrogen sequentially into the gas phase. The flow rate of nitrogen gas is usually 0.001 to 100 L / min, preferably 0.01 to 50 L / min, more preferably 0.1 to 10 L / min in terms of the amount converted to normal temperature and normal pressure. Within the above range, the concentration of by-products can be kept moderate.

In order to uniformly distribute hydrogen dissolved from the gas phase to the liquid phase in the solution or melt, it is desirable to stir the solution or melt. The stirring method is not particularly limited, but is a method of rotating and stirring the seed crystal, a method of rotating by stirring with a stirring blade, a method of stirring by giving a flow by bubbling gas into the solution or melt, Examples include a method of creating a flow with a pump and stirring.

  The growth rate of crystal growth can be adjusted by the temperature, pressure, etc., and is not particularly limited, but is usually in the range of 0.1 μm / h to 1000 μm / h, preferably 1 μm / h or more, and 10 μm / h. h or more is more preferable, and 100 μm or more is further more preferable.

  The periodic table group 13 metal nitride semiconductor crystal according to the present invention can be used for various applications. In particular, as a substrate for manufacturing a light emitting element on a relatively short wavelength side such as an ultraviolet to blue light emitting diode or a semiconductor laser, and a light emitting element on a relatively long wavelength side of green to red, it is further used for a semiconductor device such as an electronic device. It is also useful as a substrate.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

<Reference Example 1: Nitriding treatment of Ti reaction vessel (member) and crystal growth of GaN using Ti reaction vessel with no use history after nitriding treatment>
(Nitriding process for members)
The nitriding process described below will be described with reference to FIG.
(1) In an Ar box, in a Ti reaction vessel 104 (height 200.0 mm, outer diameter 34 mm, inner diameter 30 mm), 1.5 g of Li ₃ GaN ₂ as a raw material (nitriding agent) 101 having a nitriding action, In addition, 4.5 g of LiCl was sequentially added as the solvent 102. Solid Li ₃ GaN ₂ having a particle diameter of less than 2 μm was excluded using a sieve and a particle having a particle diameter of 2 μm or more was selected and used. (2) The Ti reaction vessel 104 was placed in the quartz reaction tube 105, and the gas introduction port 110 and the gas exhaust port 106 of the quartz reaction tube 105 were closed.
(3) The quartz reaction tube 105 was taken out from the Ar box and set in the electric furnace 111. (4) The quartz reaction tube was evacuated using a vacuum pump.
(5) The valve 109 is opened, N ₂ gas is introduced from the gas introduction ring 110 and the quartz reaction tube is filled with N ₂ atmosphere. Then, the valve 107 is opened, and the N ₂ gas is supplied through the gas exhaust pipe 106 to 100 cm. ^It was distributed at ³ / min.
(6) Using an electric furnace 111, the temperature inside the Ti reaction vessel 105 is raised from room temperature to 745 ° C. over 1 hour, LiCl is melted and held at 750 ° C. for 60 hours. The inner wall surface was nitrided.

(Crystal growth process)
The crystal growth process described below will be described with reference to FIG.
(1) In an Ar box, 1.5 g of solid Li ₃ GaN ₂ is put in a Ti reaction vessel 104 having no use history after nitriding, and then 15 g of LiCl is pulverized and mixed well in a tungsten carbide mortar. To Ti reaction vessel 104. Solid Li ₃ GaN ₂ having a particle diameter of less than 2 μm was excluded using a sieve and a particle having a particle diameter of 2 μm or more was selected and used.
(2) The Ti reaction vessel 104 was set in the quartz reaction tube 105, and the gas inlet 110 and the gas exhaust port 106 of the quartz reaction tube were closed.
(3) The quartz reaction tube 105 was taken out from the Ar box and set in the electric furnace 111. After connecting the gas introduction tube to the quartz reaction tube 105 and reducing the pressure in the introduction tube, the gas introduction port 110 of the quartz reaction tube is further opened to decompress the inside of the quartz reaction tube 105 and then 10 vol% of H ₂ . H ₂ / N ₂ mixed condensate pressurized with gas, the quartz reaction tube 105 was set to H ₂ / N ₂ mixed gas atmosphere of H ₂ 10 vol%. Thereafter, the gas exhaust port 106 of the quartz reaction tube was opened, and the H ₂ / N ₂ mixed gas was circulated at a flow meter set value of 100 cm ³ / min (value at standard conditions of 20 ° C. and 1 atm).
(4) Heating of the electric furnace was started, and the temperature was raised in one hour until the inside of the Ti reaction vessel 104 reached from room temperature to 750 ° C., thereby melting LiCl as a salt. After maintaining at 750 ° C. for 1 hour as a pretreatment, the seed 100 attached to the tip of the seed holding rod 108 is put into the solution (molten salt) 102 in the Ti reaction vessel, and the rotation speed of the seed crystal becomes 100 rpm. As described above, crystal growth was performed while rotating the seed crystal holding rod. At the bottom of the solution 102, Li ₃ GaN _{2 as the} raw material 101 exists in a solid state. As the seed crystal, a GaN substrate having a main surface inclined in the (0001) plane direction by 5 ° from the (10-10) plane was used.
(5) After growing for 6.3 hours, the seed crystal 100 was pulled up from the solution 102 and then the heating of the furnace was stopped, and the quartz reaction tube 105 was cooled. After cooling, the seed crystal was taken out from the quartz reaction tube 105, the salt adhering to the seed crystal was dissolved in water, and the weight of the seed crystal was measured with a weigh scale. The increase in weight of seed crystals grown was 4.9 mg. When the crystal growth rate was calculated by dividing the weight increase of the seed crystal by the growth time, the crystal growth rate was 56.6 μm / day.

<Example 1: After nitriding treatment of Ti reaction vessel (member), there is a use history after nitriding treatment, which includes a member selection step, and the change rate of length is 0. Crystal growth>
After the nitriding process, use of a reaction vessel that has a history of use for crystal growth, and before the crystal growth step, a process for selecting a member for measuring the length (height) of the reaction vessel (rate of change in length) In the same manner as in Reference Example 1 except that the crystal growth was performed under the following conditions (not an essential difference in confirming the effect of the comparison experiment). Then, GaN crystal growth was performed.

(Nitriding process for members)
It carried out on the same conditions as the reference example 1.

(Part selection process)
It was 200.0 mm when the length of reaction container made from Ti was measured with the caliper. Since the length (height) immediately after the nitriding treatment was 200.0 mm, the length change rate was calculated to be zero. Since the rate of change in length is 0, the rate of change in volume is also considered to be 0. The use of this reaction vessel was used for crystal growth without any particular judgment as to whether or not it could be used based on the rate of change in length.

(Crystal growth process)
A GaN substrate having a (11-22) plane as the main surface was used as the seed crystal.
-Crystal growth time was 6.8h.
When the weight of the seed crystal before and after crystal growth was measured, the crystal growth amount was 3.6 mg, and when the crystal growth rate was calculated, the crystal growth rate was 37.5 μm / day.

<Example 2: Using a Ti reaction vessel having a use history after nitriding treatment after nitriding treatment of a Ti reaction vessel (member), including a member selection step, and a rate of change in length of 0.5% GaN crystal growth>
After the nitriding process, using a reaction vessel that has a history of use for crystal growth, and before the crystal growth step, the reaction vessel selection step (length change rate) that measures the length (height) of the reaction vessel In the same manner as in Reference Example 1 except that the crystal growth was performed under the following conditions (not an essential difference in confirming the effect of the comparison experiment). Then, GaN crystal growth was performed.

(Nitriding process for members)
It carried out on the same conditions as the reference example 1.

(Part selection process)
It was 201.0 mm when the length of reaction container made from Ti was measured with the caliper. Since the length immediately after the nitriding treatment was 200.0 mm, the rate of change in length was calculated to be 0.5%. Since the length change rate is 0.5%, the volume change rate is considered to be 1.5%. The use of this reaction vessel was used for crystal growth without any particular judgment as to whether or not it could be used based on the rate of change in length.

(Crystal growth process)
conditions:
-As the seed crystal, a GaN substrate having a main surface inclined in the (0001) plane direction by 6 ° from the (10-10) plane was used.
-Crystal growth time was 7h.
When the weight of the seed crystal before and after crystal growth was measured, the amount of crystal growth was 4.5 mg. When the crystal growth rate was calculated, the crystal growth rate was 56.5 μm / day.

<Comparative Example 1: Nitriding treatment of Ti reaction vessel (member) and GaN crystal growth using Ti reaction vessel with history of use after nitriding treatment and length change rate of 1.0%>
After the nitriding process, use of a reaction vessel with a history of use for crystal growth, and before the crystal growth step, a reaction vessel selection step for measuring the length of the reaction vessel (whether it can be used depending on the rate of change in length) In the same manner as in Reference Example 1, except that crystal growth was performed under the following conditions (not an essential difference in confirming the effect of this comparison experiment): Crystal growth was performed.

(Nitriding process for members)
The conditions were the same as in Reference Example 1.

(Part selection process)
It was 202.0 mm when the length of reaction container made from Ti was measured with the caliper. Since the length immediately after nitriding was 200.0 mm, the rate of change in length was calculated to be 1.0%. Since the length change rate is 1.0%, the volume change rate is considered to be 3.0%. The use of this reaction vessel was used for crystal growth without any particular judgment as to whether or not it could be used based on the rate of change in length.

(Crystal growth process)
conditions:
A GaN substrate having a (11-22) plane as the main surface was used as the seed crystal.
-Crystal growth time was 6.5h.
When the weight of the seed crystal before and after crystal growth was measured, the amount of crystal growth was 0.2 mg, and the crystal growth rate was calculated. As a result, the crystal growth rate was 2.3 μm / day. The results of Reference Example 1, Examples 1 and 2, and Comparative Example 1 are collectively shown in Table 1.

  From the results of Table 1, it is confirmed that the member (reaction vessel) used in the crystal growth process expands and changes in size compared to the unused state. Further, it is apparent that the growth rate of the group 13 nitride semiconductor crystal is remarkably reduced when crystal growth is performed using a member expanded to a specific size.

100 seed crystals (GaN)
101 Raw material (Li ₃ GaN ₂ )
102 Melt or solvent (LiCl)
103 wire (made of Ta)
104 Reaction vessel 105 Quartz reaction tube 106 Gas exhaust tube 107 Valve 108 Seed crystal holding rod (W)
109 Valve 110 Gas introduction pipe 111 Electric furnace

Claims (10)

A method for selecting a member to be used for manufacturing a periodic table group 13 metal nitride semiconductor crystal,
A method for selecting a member, comprising measuring the volume and / or size of the member, and selecting the member using a volume change and / or a dimensional change from an unused state as an index. The member selection method according to claim 1, wherein a member having a maximum dimensional change rate from an unused state is 0.8% or less. The method for selecting a member according to claim 1 or 2, wherein a member having a volume change rate from an unused state of 2.4% or less is selected. The member selection method according to any one of claims 1 to 3, wherein the member includes at least one selected from Group 4 to 6 elements of the periodic table, Sc, Y, Ni, and Pd. The said member is what comprised 90 weight% or more with the metal or alloy containing the at least 1 sort (s) chosen from the periodic table group 6-6 element, Sc, Y, Ni, and Pd. The method for selecting a member according to any one of the above. The member selection method according to any one of claims 1 to 5, wherein a nitride containing at least one selected from Group 4 to 6 elements of the periodic table is formed on the surface of the member. The member selection method according to any one of claims 1 to 6, wherein the production of the Group 13 metal nitride semiconductor crystal of the periodic table is a production method in which a component containing a hydrogen element is present in a reaction system. The member according to any one of claims 1 to 7, wherein the member is at least one selected from a reaction vessel, a stirring blade, a seed crystal holding rod, a seed crystal holding table, a baffle, a gas introduction pipe, and a valve. Selection method. A selection step of selecting a member by the member selection method according to any one of claims 1 to 8, a step of preparing a solution or melt containing a raw material and a solvent, and a periodic table in the solution or melt. A manufacturing method of a periodic table group 13 metal nitride semiconductor crystal including a growth step of epitaxially growing a group 13 metal nitride semiconductor crystal,
The group 13 metal of the periodic table, wherein the step of producing the melt or solution and / or the growth step is performed using the member selected in the selection step and / or an apparatus including the member. A method for producing a nitride semiconductor crystal. The method for producing a periodic table group 13 metal nitride semiconductor crystal according to claim 9, wherein the growth step includes a component containing a hydrogen element in a reaction system.

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