WO2021014834A1 - Procédé de production de substrat de composé du groupe iii et substrat produit par ce procédé de production - Google Patents

Procédé de production de substrat de composé du groupe iii et substrat produit par ce procédé de production Download PDF

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WO2021014834A1
WO2021014834A1 PCT/JP2020/023611 JP2020023611W WO2021014834A1 WO 2021014834 A1 WO2021014834 A1 WO 2021014834A1 JP 2020023611 W JP2020023611 W JP 2020023611W WO 2021014834 A1 WO2021014834 A1 WO 2021014834A1
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substrate
group iii
gan
iii compound
seed
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PCT/JP2020/023611
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English (en)
Japanese (ja)
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芳宏 久保田
永田　和寿
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信越化学工業株式会社
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Priority claimed from JP2019180194A external-priority patent/JP7204625B2/ja
Application filed by 信越化学工業株式会社 filed Critical 信越化学工業株式会社
Priority to CN202080053287.8A priority Critical patent/CN114144864A/zh
Priority to KR1020227000694A priority patent/KR20220042111A/ko
Priority to US17/628,745 priority patent/US11932936B2/en
Priority to EP20842948.0A priority patent/EP4006213A4/fr
Publication of WO2021014834A1 publication Critical patent/WO2021014834A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/34—Nitrides
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C30B25/18—Epitaxial-layer growth characterised by the substrate
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/38—Nitrides

Definitions

  • the present invention relates to a method for producing a group III compound substrate such as GaN-based or AlN-based, which is large in size, has extremely few warpages, voids, and lattice defects, and has high characteristics and high quality, and a substrate manufactured by the manufacturing method.
  • the present invention relates to a method for manufacturing a large-sized, high-quality GaN substrate or a large-sized, high-quality AlN substrate, and a GaN substrate or AlN substrate manufactured by the manufacturing method.
  • Substrates of group III compounds such as crystalline GaN-based and AlN-based have a wide bandgap, and have excellent high-frequency characteristics with extremely short wavelength luminescence and high withstand voltage. For this reason, group III compound substrates are expected to be applied to devices such as lasers, Schottky diodes, power devices, and high-frequency devices. However, at present, it is difficult to grow large-scale, high-quality crystals of these group III compounds, so that the price is high, which hinders the expansion of applications and widespread use of these substrates.
  • a bulk GaN substrate in which GaN crystals are grown in a liquid such as liquid ammonia or Na flux is generally of relatively high quality.
  • a sapphire substrate, a GaAs substrate, a SiC substrate, and a SCAM (ScAlMgO) are used by using the organic metal vapor phase growth method (MOCVD method) and the hydride vapor phase growth method (HVPE method, THVPE method, etc.) in which crystals are grown by the vapor phase method.
  • a large-sized, that is, a large-sized, high-quality substrate can be manufactured in principle.
  • single crystal substrates such as GaN substrates and SCAM substrates that have the same or relatively close lattice constant and thermal expansion coefficient as GaN crystals are currently manufactured only in small size, and large single crystal substrates are available. Since there is no such thing, it is difficult to increase the size by epitaxial deposition.
  • Non-Patent Document 1 a plurality of tile-shaped substrates obtained by cutting a GaN single crystal obtained by the Na flux method into a honeycomb shape are bonded on a susceptor made of thermally decomposed graphite (PG), and the GaN single crystal is used. It is described that a crystal is enlarged, the enlarged GaN single crystal is used as a seed substrate, and GaN is grown on the seed substrate by an HVPE method or the like to obtain a large GaN substrate.
  • PG thermally decomposed graphite
  • Patent Document 1 a plurality of tile-shaped substrates obtained by cutting a GaN single crystal obtained from a known method such as a vapor phase method into a honeycomb shape are bonded on a susceptor made of thermally decomposed graphite (PG) to form a GaN single crystal. It is described that a large-sized GaN single crystal is used as a seed substrate, and GaN is grown on the seed substrate by an HVPE method or the like to obtain a large-sized GaN substrate.
  • PG thermally decomposed graphite
  • these methods include a PG susceptor, which can be said to be a base substrate, an alumina-based adhesive or a zirconia-based adhesive used when the PG susceptor is attached to a seed substrate, and a tile-shaped GaN single crystal or a SCAM single crystal which is a seed substrate. Since the difference in the coefficient of thermal expansion between the two and the above becomes large, the seed substrate moves, peels off, warps, etc. due to expansion and contraction due to temperature changes, and the crystal orientation and uniformity must be maintained during the film formation reaction period. It was difficult to form a film with the same orientation.
  • a large GaN substrate can be produced by using a single crystal substrate such as a Si substrate, a sapphire substrate, a SiC, or a GaAs substrate for which a relatively large diameter product is available, as a base substrate and a seed substrate. Attempted. However, due to the large mismatch of the lattice constant and the coefficient of thermal expansion between these single crystal substrates and the GaN crystal, various defects increase in the GaN substrate obtained by epitaxial deposition, and warpage and cracks occur. It becomes easier and becomes a problem.
  • a sintering aid is applied to a polycrystalline powder of GaN or AlN having the same or similar lattice constant and thermal expansion coefficient, or a powder having a mullite composition as described in Patent Document 2.
  • Ceramics are produced by adding and sintering, and the obtained ceramics are used as a base substrate, and single crystal thin films such as Si substrate, sapphire substrate, SiC substrate, GaAs substrate, GaN substrate, and AlN substrate are formed on the base substrate.
  • Attempts have also been made to obtain a large-sized GaN substrate by transferring and bonding them together to form a seed substrate, and then heteroepitaxially growing GaN on the seed substrate.
  • it is difficult to obtain a substrate having high characteristics because metal impurities in the ceramic raw material or due to the sintering aid or the like are diffused and contaminated during the epitacal GaN film formation.
  • Patent Document 3 AlN ceramics, which is relatively close to the coefficient of thermal expansion of GaN, is used as the base substrate, and the entire substrate is made of a multilayer of inorganic substances such as Si, SiO 2 , and Si 3 N 4. After wrapping it in a film and sealing it, after laminating SiO 2 on it, a thin film of Si ⁇ 111> of the seed substrate is transferred and bonded, and then GaN is epitaxially formed to prevent the diffusion of metal impurities from the base substrate. Proposals have been made. However, since many steps are required for wrapping and sealing with a multi-layered inorganic substance, it is costly and uneconomical, and it is extremely difficult to ensure a perfect sealing property by the multi-layered film.
  • the present invention has been made in view of the above circumstances, and provides a method for producing a large-sized, high-quality group III compound substrate such as a GaN-based or AlN-based substrate, and a group III compound substrate obtained by the method, particularly a GaN substrate or an AlN substrate.
  • the purpose is to do.
  • the present invention provides the following method for producing a group III compound substrate and the substrate thereof. That is, [1]
  • the seed substrate is formed by a base substrate forming step of forming a base substrate of Group III nitride by a vapor phase synthesis method, a seed substrate forming step of forming a seed substrate on the base substrate, and a hydride vapor phase growth method.
  • a method for producing a Group III compound substrate which comprises a Group III compound crystal forming step of forming a Group III compound crystal on the substrate.
  • the group III nitride of the base substrate is GaN or AlN
  • the seed substrate is a substrate of Si ⁇ 111>, sapphire, SiC, GaAs, SCAM (ScAlMGO 4 ) or GaN
  • the seed substrate is formed.
  • the seed substrate is formed on the base substrate by transferring the seed substrate to the base substrate in a thin film.
  • a method for producing a group III compound substrate is
  • the base substrate is a substrate of at least one substance selected from the group consisting of amorphous, polycrystalline, single crystal, and ceramics of Group III nitride, and other than Group III metal elements in the base substrate.
  • the base substrate is formed by molding a powder of Group III nitride obtained by the hydride vapor phase growth method to prepare a molded product, and after incorporating a Group III metal into the molded product by an impregnation method, the molded product is used.
  • a substrate obtained by sintering the molded product or a powder of Group III nitride obtained by the hydride vapor phase growth method is molded to prepare a molded product, which becomes a Group III metal when reduced.
  • the Group III compound according to any one of the above [1] to [5] which is a substrate obtained by incorporating the compound into the molded product by an impregnation method, and then nitriding and sintering the molded product.
  • Substrate manufacturing method For the base substrate, a group III metal was added and mixed with the powder of the group III nitride obtained by the hydride vapor phase growth method to prepare a mixture, and the mixture was molded to prepare a molded product.
  • the N-plane group III nitride layer is formed on the seed substrate at a temperature of 400 to 800 ° C. by the low temperature MOCVD method or by the THVPE method.
  • the N-plane III-nitride layer forming step the N-plane III-nitride layer is formed on the seed substrate at a temperature of 500 to 600 ° C. by a low-temperature MOCVD method [10].
  • the method for producing a group III compound substrate according to. [12] The total of the thickness of the seed substrate or the thickness of the seed substrate and the thickness of the N-plane group III nitride layer formed in the N-plane III group nitride layer forming step is 50 to The method for producing a group III compound substrate according to any one of the above [1] to [11], which is 2000 nm.
  • a peeling layer forming step of forming a peeling layer made of a material having a peelable cleavage property is further included on the base substrate, and the seed substrate forming step forms a seed substrate on the peeling layer.
  • SCAM ScAlMgO 4
  • BN boron nitride
  • graphite graphite
  • the intermediate layer is a film of a Si-based compound
  • the seed substrate forming step forms a seed substrate on the intermediate layer.
  • the intermediate layer forming step of forming an intermediate layer on the base substrate is further included, the intermediate layer is a film of a Si-based compound, and the seed substrate forming step forms a seed substrate on the intermediate layer.
  • a larger and higher quality group III compound substrate can be obtained at low cost while taking advantage of the high film formation rate, which is a feature of the hydride vapor phase growth method. That is, since an extremely thick Group III compound substrate having a large diameter and no variation can be produced, a large-diameter Group III compound substrate having excellent crystal characteristics and low cost can be easily obtained.
  • FIG. 1 is a diagram for explaining a reaction apparatus used for producing a base substrate and forming crystals on a seed substrate in Example 1.
  • FIG. 2 is a diagram for explaining a reaction apparatus used for producing a base substrate and forming crystals on a seed substrate in Example 1.
  • the method for producing a group III compound substrate of the present invention includes a base substrate forming step of forming a base substrate of a group III nitride by a vapor phase synthesis method, a seed substrate forming step of forming a seed substrate on the base substrate, and a hydride gas.
  • the phase growth method includes a group III compound crystal forming step of forming a group III compound crystal on a seed substrate.
  • a base substrate of group III nitride is formed by a vapor phase synthesis method.
  • a high-purity base substrate can be obtained. Therefore, when a group III compound crystal is formed on the seed substrate by the hydride vapor phase growth method, metal impurities are diffused and contaminated from the base substrate into the group III compound crystal. Can be suppressed.
  • the group III nitride of the base substrate is preferably GaN or AlN.
  • the base substrate is preferably a substrate of at least one substance selected from the group consisting of amorphous, polycrystalline, single crystal, and ceramics of Group III nitride.
  • the group III compound substrate to be obtained is a GaN substrate or an AlN substrate
  • the base substrate is an amorphous, polycrystalline, single crystal of GaN or AlN that is closer to the thermal expansion coefficient of the GaN substrate or AlN substrate. It is preferable that any of the ceramics or a mixture of these is used.
  • a powder of Group III nitride obtained by the hydride vapor phase growth method is molded to prepare a molded product, and a Group III metal is contained in the molded product by an impregnation method, and then the molded product is sintered.
  • the substrate obtained in the above process or the powder of the Group III nitride obtained by the hydride vapor phase growth method is molded to prepare a molded product, and the Group III compound which becomes a Group III metal when reduced is molded by the impregnation method. It is preferable that the substrate is obtained by nitrided and sintered the molded product after being contained in the body.
  • the base substrate is formed by adding and mixing a group III metal to the powder of the group III nitride obtained by the hydride vapor phase growth method to prepare a mixture, molding the mixture to prepare a molded product, and then molding. It may be a substrate obtained by nitriding and sintering a body. As a result, a large-diameter, high-purity base substrate can be produced at low cost.
  • the base substrate is formed by using gallium nitride powder produced by heating high-purity Ga 2 O 3 powder in an ammonia atmosphere. ..
  • the base substrate is formed by using the powder of the group III nitride obtained by nitriding the powder of the group III oxide.
  • the base substrate was formed by molding the powder of the group III nitride obtained by nitriding the powder of the group III oxide to prepare a molded body, and the group III metal was contained in the molded body by the impregnation method.
  • a substrate obtained by sintering the molded body or a powder of a group III nitride obtained by nitrided powder of a group III oxide is molded to prepare a molded body, and when it is reduced, III It may be a substrate obtained by incorporating a group III compound to be a group metal into a molded body by an impregnation method, and then nitriding and sintering the molded body. Further, for the base substrate, a group III metal is added and mixed with the group III nitride powder obtained by nitriding the group III oxide powder to prepare a mixture, and the mixture is molded to form a molded body. It may be a substrate obtained by nitriding and sintering a molded body after production. By using a high-purity group III oxide, a large-diameter, high-purity base substrate can be produced at low cost.
  • the base substrate can be produced using the GaN or AlN powder produced as follows.
  • GaN or AlN powder can be produced by directly nitriding Ga metal or Al metal in an NH 3 atmosphere, and Ga metal or Al metal is arced in NH 3.
  • GaN or AlN powder can be produced by causing a plasma reaction.
  • GaN powder or AlN powder can also be produced by nitriding the Ga metal or Al metal while pulverizing it in N 2 or NH 3 .
  • a GaN or AlN substrate is produced by adding a sintering aid such as SiO 2 or a binder to the GaN powder or AlN powder thus obtained, mixing, molding, and sintering. Can be done.
  • a sintering aid such as SiO 2 or a binder
  • impurities are mixed in from the crushing container and crushed media used at the time of manufacturing, especially when crushing the raw metal, or the electrode components are contaminated due to the consumption of the arc electrode, and metals other than Ga or Al are generated. Since a large amount of impurities are mixed, it is not suitable for the base substrate forming step in the method for producing a group III compound substrate of the present invention.
  • a method for producing a base substrate suitable for the method for producing a group III compound substrate of the present invention for example, Ga metal or Al metal or a halide thereof is subjected to a gas phase oxidation reaction to cause Ga 2 O 3 powder or Al 2 O 3 after obtaining the powder, after preparing a molded body by molding them, and a method of nitriding in a reducing atmosphere such as N 2, NH 3.
  • a gas phase oxidation reaction to cause Ga 2 O 3 powder or Al 2 O 3 after obtaining the powder, after preparing a molded body by molding them, and a method of nitriding in a reducing atmosphere such as N 2, NH 3.
  • a hydride vapor phase growth method is carried out under reduced pressure using high-purity Ga chloride or Ga bromide or Al chloride or Al bromide and NH 3 as raw materials, and GaN or directly.
  • a method for obtaining an AlN substrate the above vapor phase growth method is carried out at normal pressure or higher to obtain a high-purity GaN or AlN powder, and then the powder is pressure-molded and sintered to obtain GaN or
  • a high-purity Ga metal or a high-purity Al metal is further added and mixed, and then pressure-molded to prepare a molded product.
  • a step of impregnating the pores of the substrate with high-purity Ga metal or high-purity Al metal and then nitriding and sintering is provided. May be good.
  • high-purity Ga 2 O 3 powder or Al 2 O 3 powder is heated in an ammonia atmosphere. It is also possible to obtain a high-purity GaN powder or a high-purity AlN powder, and a GaN or AlN base substrate can be obtained using this.
  • the total content of metal impurities other than group III metal elements in the base substrate is 5000 mass ppm or less in terms of metal.
  • the total content of metal impurities other than the group III metal element in the base substrate is 5000 mass ppm or less in terms of metal, the diffusion of impurities from the base substrate to the group III compound crystal is suppressed, and the high-characteristic group III compound A substrate can be obtained.
  • the base substrate is a GaN substrate
  • the total content of metal impurities other than Ga is preferably 5000 mass ppm or less in terms of metal.
  • the base substrate is an AlN substrate
  • the total content of metal impurities other than Al is preferably 5000 mass ppm or less in terms of metal.
  • the seed substrate is formed on the base substrate. It is preferable to form the seed substrate on the base substrate by transferring the seed substrate to the base substrate as a thin film.
  • the seed substrate is preferably a substrate of Si ⁇ 111>, sapphire, SiC, GaAs, SCAM (ScAlMgO 4 ) or GaN.
  • the thickness of the seed substrate is preferably 50 to 2000 nm. When the thickness of the seed substrate is 50 nm or more, the effect of the seed substrate can be sufficiently exerted, and the occurrence of many defects during film formation can be suppressed.
  • the seed substrate when the thickness of the seed substrate is 2000 nm or less, it is possible to prevent the seed substrate from warping or cracking or peeling from the seed substrate.
  • the seed substrate may be formed directly on the base substrate, or at least one layer may be interposed between the seed substrate and the base substrate to form the seed substrate.
  • the substrate may be formed on the base substrate.
  • the seed substrate is preferably a substrate of Si ⁇ 111>, sapphire, SiC, GaAs, SCAM (ScAlMgO 4 ) or GaN.
  • Si ⁇ 111>, sapphire, SiC, GaAs, SCAM (ScAlMgO 4 ) or GaN has the same or similar crystal structure as GaN or AlN.
  • a step of implanting ions such as hydrogen and Ar into the surface of a substrate for supplying seed substrates of Si ⁇ 111>, sapphire, SiC, GaAs, SCAM (ScAlMgO 4 ) or GaN, and the surface portion where the ions are implanted is used as a base substrate. It is most preferable to transfer a uniform thin film to the base substrate through a step of joining and a step of peeling the ion-implanted surface portion bonded to the base substrate from the seed substrate supply substrate.
  • Group III compound crystal formation step a group III compound crystal is formed on the seed substrate by a hydride vapor phase growth method.
  • the group III compound crystal forming step it is preferable to form a group III compound crystal on a seed substrate by using a group III chloride and NH 3 as a gas phase growth raw material.
  • the group III compound crystal is preferably a gallium nitride (GaN) crystal or an aluminum nitride (AlN) crystal. Further, it may be a binary group III compound crystal to which Al, In, Ga or the like is added in order to improve the characteristics of the substrate, or a multidimensional group III compound crystal such as a ternary system.
  • the group III compound crystal can contain various dopants, if necessary. If the group III compound crystal is formed on the seed substrate, the group III compound crystal may be formed directly on the seed substrate, or at least one layer is formed between the group III compound crystal and the seed substrate. May be intervened to form Group III compound crystals on the seed substrate.
  • the case of manufacturing a GaN base or large and high-quality AlN-based group-III compound single crystal in a hydride vapor phase epitaxy a GaN by using the main GaCl 3 or AlCl 3 and NH 3 as a vapor deposition material
  • a hydride vapor phase growth method can be selected from the HVPE method and the THVPE method depending on the required crystal characteristics, but may also be combined with the organic metal vapor phase growth method (MOCVD method) in some cases.
  • MOCVD method organic metal vapor phase growth method
  • the THVPE method in which the crystal growth rate is high and the crystal diameter increases with growth, is particularly preferable.
  • the produced crystal may be used as it is as a substrate, or the produced crystal may be processed and the processed crystal may be used as a substrate. In some cases, the produced crystal may be used as a base substrate.
  • the method for producing a group III compound substrate of the present invention may further include an N-plane group III nitride layer forming step.
  • an N-plane group III nitride layer is formed on the seed substrate between the seed substrate forming step and the group III compound crystal forming step.
  • the group III nitrogen product layer on the N-plane is a group III nitrogen product layer whose surface is a surface on which nitrogen atoms are lined up.
  • the N-plane group III nitride layer forming step it is preferable to form the N-plane group III nitride layer on the seed substrate at a temperature of 400 to 800 ° C. by the low temperature MOCVD method or by the THVPE method. This makes it possible to easily form an N-plane III-nitride layer on the seed substrate.
  • the N-plane III-nitride layer is formed on the seed substrate by the low-temperature MOCVD method, the N-plane III-nitride layer is formed on the seed substrate at a temperature of 500 to 600 ° C. Is more preferable.
  • the HVPE method tends to form a surface in which Ga atoms are arranged on the upper surface or a surface in which Al atoms are arranged
  • the THVPE method using GaCl 3 or AlCl 3 as a raw material tends to form a surface in which N atoms are arranged on the upper surface. Therefore, when the N-plane III-nitride layer is an N-plane GaN layer or an N-plane AlN layer, it is preferable to form an N-plane III-nitride layer on the seed substrate by the THVPE method.
  • the total film thickness of the seed substrate and the group III nitride layer on the N-plane is preferably 50 to 2000 nm.
  • a group III nitride layer on the N-plane may be formed on the seed substrate by a low-temperature MOCVD method at a film formation temperature of preferably 400 to 800 ° C., more preferably 500 to 600 ° C.
  • the film formation temperature of the low-temperature MOCVD method is 400 ° C. or higher, the N-plane III-nitride layer can be formed on the seed substrate in a short time, and the film quality of the N-plane III-nitride layer can be improved. Can be done well.
  • the film formation temperature of the low-temperature MOCVD method is 800 ° C.
  • the formation of a surface in which Ga atoms are arranged or a surface in which Al atoms are arranged is suppressed on the surface of the group III nitride layer, and the N-plane is formed.
  • a group III nitride layer can be easily formed.
  • the method for producing a group III compound substrate of the present invention may further include a release layer forming step of forming a release layer made of a substance having a releasable cleavage property on a base substrate.
  • a release layer forming step By providing a release layer between the base substrate and the seed substrate, the Group III compound crystals grown on the seed substrate and the base substrate can be easily separated, and the base substrate can be recycled without loss.
  • the method for producing a group III compound substrate of the present invention further includes a release layer forming step, the seed substrate is formed on the release layer in the seed substrate forming step.
  • the substances having cleaving property are SCAM (ScAlMgO4) crystal having cleaving property, hexagonal boron nitride (BN) having a crystal structure that is easily peeled off in layers, graphite, and PBN having a partially disordered layer structure. It is preferably at least one substance selected from the group consisting of (thermally decomposed boron nitride) and PG (thermally decomposed graphite), and at least one selected from the group consisting of SCAM crystals, boron nitride and graphite. It is more preferably a substance.
  • the release layer may be adhered to the base substrate using a normal heat-resistant inorganic adhesive, or by a physical method such as a reduced pressure vapor phase method or spatter. A release layer of any thickness may be laminated on the base substrate.
  • the method for producing a group III compound substrate of the present invention may further include an intermediate layer forming step.
  • Si, SiO 2 as a base for forming the seed substrate, on the base substrate between the base substrate shaping step and the seed substrate forming step, or on the peeling layer when the peeling layer is formed, A film of a Si-based compound such as Si 3 N 4 or SiO x N y is formed.
  • contamination of metal impurities from the base substrate and the release layer can be further suppressed, and a large-sized, warped, void, and lattice defect can be extremely reduced, and a high-quality group III compound substrate with high characteristics can be produced.
  • SiO 2 and Si 3 N 4 are preferable, and SiO 2 is more preferable.
  • the method for forming the intermediate layer is not particularly limited, but it is preferable to form the intermediate layer by a plasma CVD (chemical vapor deposition) method or the like. Further, after forming the intermediate layer, it is preferable to polish the intermediate layer by CMP (chemical mechanical polishing) or the like.
  • the group III compound substrate of the present invention is produced by the method for producing a group III compound substrate of the present invention.
  • a group III compound substrate of the present invention By the method for producing a group III compound substrate of the present invention, an extremely thick group III compound substrate can be obtained for the first time with a large diameter and no variation.
  • a substrate with excellent crystal characteristics and low cost can be obtained, and the group III compound substrate can be applied to devices such as lasers, power devices, and high-frequency devices, which have not been widely used in terms of characteristics and cost. It becomes.
  • Example 1 (1) Preparation of Base Substrate The fabrication of the base substrate in Example 1 will be described with reference to FIGS. 1 and 2.
  • An alumina mat-like heat insulating material 10 is placed inside a stainless steel reactor (the inner surface is coated by spraying zirconia very thinly in advance) with an inner diameter of 1500 mm and a height of 1800 mm, which has a water-cooled jacket and an exhaust port.
  • Heating device 9 inner diameter 1000 mm x height 1300 mm
  • gas supply pipe 5 gas supply pipe 5 (same material as the above reactor, center tube 6; inner diameter ⁇ 30 mm, second tube 8; inner diameter ⁇ 40 mm) having a cylindrical rod-shaped SiC heater , Outermost pipe 7; inner diameter ⁇ 50 mm) was provided.
  • PBN pyrolytic boron nitride
  • a 520 mm ⁇ 520 mm PBN-coated graphite susceptor revolutionary jig 4 for arranging and storing the susceptors 3 at 120 ° intervals was prepared. While heating the susceptor surface to 1250 ° C. with a heater, the susceptor revolution jig 4 rotates at 10 rpm to revolve the susceptor 3, and the force of the revolution gear is used to rotate each of the three susceptors 3 at 30 rpm. It was. After confirming the stability of the temperature and rotation of the susceptor, the GaCl 3 gas from the central tube 6 of the triple tube, the NH 3 gas from the outermost tube 7 and the central tube 6 and the outermost tube 7 were placed inside the reactor 1.
  • the GaN film growth was carried out at a film growth rate of about 30 ⁇ m / h for 30 hours to form GaN crystals 2 on the PBN.
  • the obtained GaN crystal was peeled from the PBN susceptor at a portion where PBN was easily delaminated. Then, the peeled GaN crystal was made into a disk having a diameter of 155 mm by a lathe.
  • the PBN layer of the disc was completely removed by polishing the disc with a fixed grindstone. Further, using a grindstone, both sides of the disk were further polished to a disk thickness of 750 ⁇ m.
  • the GaN surface was mirror-finished by CMP to smooth the surface of the disk, and a GaN base substrate was produced.
  • the difference in the coefficient of thermal expansion between the GaN base substrate and the GaN single crystal was measured, it was as small as about 0.1 ⁇ 10 -6 / ° C.
  • the coefficient of thermal expansion of the GaN single crystal is about 5.6 ppm / K at 500 ° C.
  • the GaN substrate at the top layer (the GaN substrate at the position farthest from the seed substrate) is X-ray locking on the (100) plane.
  • the FWHM Full Width at Half Maximum
  • the average of any three points in the plane was 15 arcsec, and the variation was 1 arcsec, and this substrate was a substrate with extremely good crystallinity.
  • the average of any three points in the plane is 55 arcsec in the FWHM of the X-ray locking curve of the (100) plane.
  • the variation was 8 arcsec, and the crystallinity was slightly inferior to that of the GaN substrate in the uppermost layer, but this substrate was also a substrate with good crystallinity.
  • metal contamination on the GaN substrate was below the detection limit for both the GaN substrate in the uppermost layer and the GaN substrate in the lowermost layer.
  • Comparative Example 1 A GaN powder obtained by reacting Ga metal with arc plasma in NH 3 was prepared. This GaN powder was molded on a substrate by a press to prepare a molded product. NH 3 atmosphere molded body was prepared base substrate and fired at a firing temperature of 1300 ° C.. Other than that, the GaN substrate of Comparative Example 1 was produced by the same method as the method for producing the GaN substrate of Example 1. As a result of measuring the metal contamination of the GaN substrate in the uppermost layer, it was found that a total of 8500 mass ppm of metal impurities such as Cu and Fe, which are thought to be from the Cu electrode of the arc plasma apparatus, were mixed in the GaN substrate.
  • metal impurities such as Cu and Fe
  • Such a GaN substrate having a high content of metal impurities cannot be flowed to the line due to concerns about contamination of the device manufacturing line. Further, when the FWHM of the GaN substrate of Comparative Example 1 was measured, the average of any three points in the plane was 7800 arcsec and the variation was 3000 arcsec due to the influence of metal impurities, and the GaN substrate of Comparative Example 1 was extremely It was a substrate with poor crystallinity.
  • Example 2 (1) Fabrication of base substrate
  • the total pressure of GaCl 3 and NH 3 is 3 Torr in gauge pressure under positive pressure, that is, at normal pressure + 3 Toor pressure, GaCl.
  • High-purity GaN powder was prepared by a hydride vapor phase reaction using 3 and NH 3 as raw materials. To this, 1 part by mass of Ga metal was added to 100 parts by mass of GaN powder and mixed to prepare a mixture. The mixture was pressure-molded with a pressure press under the conditions of a pressure of 30 kg / cm 2 and a temperature of 25 ° C. to prepare a molded product. The molded product was nitrided and sintered at a firing temperature of 1200 ° C. in a mixed gas atmosphere of 10% by volume N 2 gas and 90% by volume NH 3 gas to prepare a base substrate.
  • the GaN substrate in the uppermost layer is the average of any three points in the plane in the FWHM of the X-ray locking curve of the (100) plane.
  • the variation was 1 arcsec, and this substrate was a substrate having extremely good crystallinity.
  • the average of any three points in the plane is 45 arcsec and the variation is 4 arcsec in the FWHM of the X-ray locking curve of the (100) plane.
  • the crystallinity was slightly inferior to that of the GaN substrate in the uppermost layer, this substrate was also a substrate with good crystallinity.
  • the GaN substrate crystal of Example 2 is a large-sized, high-quality GaN crystal substrate. It is presumed that the GaN substrate of Example 2 having good crystallinity and few metal impurities is due to the effect of the N-plane GaN layer laminated on Si ⁇ 111> of the seed substrate.
  • Example 3 (1) Fabrication of base substrate
  • the total pressure of GaCl 3 and NH 3 is 3 Torr in gauge pressure under positive pressure, that is, at normal pressure + 3 Toor pressure, GaCl.
  • High-purity GaN powder was prepared by a hydride vapor phase reaction using 3 and NH 3 as raw materials. 30kg / cm under the temperature conditions of the pressure ⁇ 1050 ° C. for 2, in N 2 gas atmosphere, the mixture heating and pressure molding in a heated press to prepare a ⁇ 6-inch wafer-shaped base substrate.
  • the transferred SCAM thin film was lightly polished with CMP to make the thickness of the SCAM thin film 0.7 ⁇ m, which was used as a seed substrate.
  • the N-plane GaN crystal was not laminated on the seed substrate. Further, the SCAM substrate remaining on the glass substrate after the SCAM thin film was peeled off could be used again as a seed substrate.
  • a GaN crystal is formed on the seed substrate in the same manner as in Example 1, and the obtained GaN crystal is processed to prepare the GaN substrate of Example 3. did.
  • the obtained GaN crystal could be easily peeled off from the SCAM thin film which is the seed substrate. Further, in the region several hundred ⁇ m from the seed substrate of the obtained GaN crystal, the GaN crystal was slightly colored yellow, but in the other regions, the GaN crystal was not colored.
  • the GaN substrate in the uppermost layer is the average of any three points in the plane in the FWHM of the X-ray locking curve of the (100) plane.
  • the variation was 2 arcsec, and this substrate was a substrate having extremely good crystallinity.
  • the average of any three points in the plane is 20 arcsec and the variation is 3 arcsec in the FWHM of the X-ray locking curve of the (100) plane.
  • the crystallinity of the GaN substrate in the lowermost layer was almost the same as the crystallinity of the GaN substrate in the uppermost layer.
  • GaCl 3 gas was changed to GaCl gas, and the film formation method was changed from the THVPE method to the HVPE method. Except for this, a GaN crystal was formed on the seed substrate in the same manner as in Example 3, and the obtained GaN crystal was processed to prepare the GaN substrate of Comparative Example 2. However, the flow rate of the GaCl gas was changed so that the supply amount of the Ga element was the same as that in the case of the GaCl 3 gas.
  • the substrate diameter of the GaN substrate in the lowermost layer was about 6 inches, but the substrate diameter of the GaN substrate in the uppermost layer was about. It became 4 inches. From this, in Comparative Example 2, the GaN crystal formed on the seed substrate was dwarfed toward the upper layer. Therefore, it was not possible to obtain a large number of target ⁇ 6 inch GaN substrates, and the diameters of the obtained GaN substrates were different.
  • the average of any three points in the plane is 1350 arcsec and the variation is 200 arcsec in the FWHM of the X-ray locking curve of the (100) plane.
  • this substrate was a substrate with extremely poor crystallinity.
  • the content of metal impurities in the GaN substrate in the uppermost layer is 5300 mass ppm
  • the content of metal impurities in the GaN substrate in the lowermost layer is 95000 mass ppm.
  • the content of metal impurities was large.
  • Such a GaN substrate having a high content of metal impurities cannot be flowed to the line due to concerns about contamination of the device manufacturing line.
  • Example 4 (1) Preparation of Base Substrate A ⁇ 155 mm AlN substrate was prepared as a base substrate by the same method as in Example 1 except that the GaCl 3 gas was replaced with AlCl 3 gas and the reaction temperature was changed from 1250 ° C. to 1500 ° C. did.
  • the coefficient of thermal expansion of the AlN substrate is about 5.7 ppm at 500 ° C.
  • a plurality of ⁇ 2 inch AlN substrates (thickness 200 ⁇ m) were prepared by the flux method.
  • a plurality of ⁇ 2 inch AlN substrates were processed into a honeycomb shape.
  • a plurality of honeycomb-shaped AlN substrates were attached to a separately prepared glass substrate so as to form a ⁇ 6 inch disk.
  • hydrogen ions were injected into the AlN substrate to a depth of 1 ⁇ m, and the hydrogen ion driving surface of the AlN substrate into which the hydrogen ions were injected was bonded to the base substrate on which the SiO 2 film was formed and bonded to the base substrate.
  • the AlN thin film was peeled off from the AlN substrate, and the AlN thin film having a thickness of 1 ⁇ m was transferred to the base substrate. Then, the transferred AlN thin film was lightly polished with CMP to make the thickness of the AlN thin film 0.9 ⁇ m, which was used as a seed substrate.
  • the AlN substrate in the uppermost layer is the average of any three points in the plane in the FWHM of the X-ray locking curve of the (100) plane.
  • the variation was 3 arcsec, and this substrate was a substrate having extremely good crystallinity.
  • the average of any three points in the plane is 45 arcsec and the variation is 8 arcsec in the FWHM of the X-ray locking curve of the (100) plane.
  • the crystallinity was slightly inferior to that of the AlN substrate in the uppermost layer, but this substrate was also a substrate with good crystallinity.
  • metal contamination on the AlN substrate was below the detection limit for both the AlN substrate in the uppermost layer and the AlN substrate in the lowermost layer.
  • Example 5 (1) Preparation of Base Substrate A ⁇ 6 inch wafer-shaped base substrate was prepared in the same manner as in Example 3.
  • Si 3 N 4 film formation (intermediate layer formation) On the upper surface of the base substrate to 0.5 ⁇ m laminating Si 3 N 4 by plasma CVD apparatus and an Si 3 N 4 film, polished lightly the Si 3 N 4 film in CMP, the Si 3 N 4 film The thickness was 0.4 ⁇ m.
  • the SCAM thin film was peeled off from the SCAM substrate, and the SCAM thin film having a thickness of 1 ⁇ m was transferred to the base substrate.
  • the transferred SCAM thin film was lightly polished with CMP to make the thickness of the SCAM thin film 0.7 ⁇ m, which was used as a seed substrate.
  • the GaN substrate in the uppermost layer is the average of any three points in the plane in the FWHM of the X-ray locking curve of the (100) plane.
  • the variation was 2 arcsec, and this substrate was a substrate with good crystallinity.
  • the average of any three points in the plane is 22 arcsec and the variation is 3 arcsec in the FWHM of the X-ray locking curve of the (100) plane.
  • the crystallinity of the GaN substrate in the lowermost layer was almost the same as the crystallinity of the GaN substrate in the uppermost layer.
  • metal contamination on the GaN substrate was below the detection limit in the GaN substrates in the uppermost layer and the lowermost layer.
  • Example 6 (1) Preparation of Base Substrate Using GaCl 3 and NH 3 as raw materials, a base substrate made of GaN having a diameter of 8 inches and a thickness of 800 ⁇ m was prepared under the same conditions as in Example 1.
  • a low-temperature MOCVD reaction was carried out on this seed substrate at a film formation temperature of 550 ° C. using trimethylgallium (TMG) and NH 3 as raw materials for 3 hours, and 0.6 ⁇ m of N-plane GaN crystals were laminated on the seed substrate.
  • TMG trimethylgallium
  • NH 3 trimethylgallium
  • the total thickness of the seed substrate and the GaN crystal on the N-plane was 1.1 ⁇ m.
  • the stripped GaN crystal and the Si ⁇ 111> seed crystal were first cylindrically ground, and then the Si ⁇ 111> seed crystal was polished and removed, and then sliced to a thickness of 800 ⁇ m.
  • the obtained 16 GaN substrates were subjected to final CMP polishing from lap polishing to obtain a smooth GaN substrate product having a thickness of 625 ⁇ m.
  • the GaN substrate immediately after crystal growth absorbed thermal stress by successive cleavage during the reaction due to the action of SCAM of the peeling layer, so that almost no warp occurred and no cracks occurred at all.
  • Example 7 (1) Preparation of base substrate A high-purity GaN powder was prepared in the same procedure as in Example 2. 10 parts by mass of Ga metal was added to 100 parts by mass of this GaN powder and mixed to prepare a mixture. The mixture was pressure-molded with a pressure press under the conditions of a pressure of 30 kg / cm 2 and a temperature of 25 ° C. to prepare a molded product. The molded product was nitrided and sintered at a firing temperature of 1200 ° C. in a mixed gas atmosphere of 10% by volume N 2 gas and 90% by volume NH 3 gas to prepare a base substrate.
  • Si 3 N 4 film formation (intermediate layer formation) A Si 3 N 4 film was laminated on the surface of this release layer with a plasma CVD apparatus, and the surface of the Si 3 N 4 film was polished to obtain a surface roughness Ra of the Si 3 N 4 film of 0.5 ⁇ m.
  • a low-temperature MOCVD reaction was carried out on this seed substrate at a film formation temperature of 550 ° C. using trimethylgallium (TMG) and NH 3 as raw materials for 3 hours, and 0.6 ⁇ m of N-plane GaN crystals were laminated on the seed substrate.
  • TMG trimethylgallium
  • NH 3 trimethylgallium
  • the total thickness of the seed substrate and the GaN crystal on the N-plane was 1.1 ⁇ m.
  • a GaN crystal was formed on the seed substrate under the same conditions as when the base substrate was produced, using the apparatus used for producing the base substrate.
  • the crystal growth rate was about 200 ⁇ m / h, and the GaN film growth was continued for 100 hours.
  • the obtained GaN crystal was easily peeled from the PBN of the peeling layer in the form of being integrated with the seed substrate.
  • the worrying thermal stress during cooling was absorbed by delamination. As a result, no cracks were generated in the GaN crystal, and almost no warpage was generated.

Abstract

Ce procédé de production de substrat de composé du groupe III comprend une étape de formation de substrat de base pour former un substrat de base de nitrure du groupe III par dépôt en phase vapeur, une étape de formation de substrat de germe pour former un substrat de germe sur le substrat de base, et une étape de formation de cristal de composé du groupe III pour former un cristal de composé du groupe III sur le substrat de germe par épitaxie en phase vapeur d'hydrure. Le substrat de composé du groupe III est caractérisé en ce qu'il est produit à l'aide de ce procédé de production de substrat de composé du groupe III. Grâce à la présente invention, il est possible d'obtenir un substrat de composé du groupe III de plus grande qualité et plus grand à moindre coût, tout en bénéficiant de la vitesse de formation de film élevée qui est caractéristique de l'épitaxie en phase vapeur d'hydrure.
PCT/JP2020/023611 2019-07-25 2020-06-16 Procédé de production de substrat de composé du groupe iii et substrat produit par ce procédé de production WO2021014834A1 (fr)

Priority Applications (4)

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CN202080053287.8A CN114144864A (zh) 2019-07-25 2020-06-16 Iii族化合物基板的制造方法和利用该制造方法制造的基板
KR1020227000694A KR20220042111A (ko) 2019-07-25 2020-06-16 Iii 족 화합물 기판의 제조 방법 및 그 제조 방법에 의해 제조한 기판
US17/628,745 US11932936B2 (en) 2019-07-25 2020-06-16 Method for producing a group III compound crystal by hydride vapor phase epitaxy on a seed substrate formed on a group III nitride base substrate
EP20842948.0A EP4006213A4 (fr) 2019-07-25 2020-06-16 Procédé de production de substrat de composé du groupe iii et substrat produit par ce procédé de production

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006528592A (ja) * 2003-07-24 2006-12-21 エス　オー　イ　テク　シリコン　オン　インシュレータ　テクノロジース エピタキシャル成長層の形成方法
JP2012116741A (ja) * 2010-11-12 2012-06-21 Sumitomo Electric Ind Ltd Ｉｉｉ族窒化物複合基板
JP2017210391A (ja) * 2016-05-27 2017-11-30 国立大学法人東北大学 窒化物半導体自立基板作製方法
WO2019054444A1 (fr) * 2017-09-14 2019-03-21 国立大学法人東京農工大学 Procédé de production d'un film de cristaux de nitrure de gallium

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Publication number Priority date Publication date Assignee Title
JP2006528592A (ja) * 2003-07-24 2006-12-21 エス　オー　イ　テク　シリコン　オン　インシュレータ　テクノロジース エピタキシャル成長層の形成方法
JP2012116741A (ja) * 2010-11-12 2012-06-21 Sumitomo Electric Ind Ltd Ｉｉｉ族窒化物複合基板
JP2017210391A (ja) * 2016-05-27 2017-11-30 国立大学法人東北大学 窒化物半導体自立基板作製方法
WO2019054444A1 (fr) * 2017-09-14 2019-03-21 国立大学法人東京農工大学 Procédé de production d'un film de cristaux de nitrure de gallium

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PHYS. STATUS SOLIDI B, vol. 254, no. 8, 2017, pages 1600671

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