JP5493160B2 - Functional material and manufacturing method thereof - Google Patents

Description

  The present invention relates to a functional material formed by subjecting two or more types of solid materials to high-gravity field treatment and a method for manufacturing the functional material.

  Examples of the junction include a pn junction, a pin junction, a hetero junction, a Schottky junction, and a MOS junction. A pn junction is a junction between a p-type semiconductor and an n-type semiconductor, and a pin junction is a junction between a p-type semiconductor, an intrinsic semiconductor, and an n-type semiconductor. A heterojunction is a junction between semiconductors having different band gaps, a Schottky junction is a junction between a metal and a semiconductor, and a MOS junction is a junction between a metal, an insulator, and a semiconductor.

  Diodes and transistors are manufactured by epitaxial growth, surface bonding, or point bonding of n-type and p-type semiconductors. At this time, the width of the reaction layer varies depending on the type of the diode or transistor, and is related to performance. Here, the reaction layer is a layer existing at the boundary (junction surface) between the n-type semiconductor and the p-type semiconductor. For example, the n-type impurity concentration gradient starts to increase rapidly, and the p-type This is a layer existing between the point where the impurity concentration gradient starts to increase rapidly.

  When manufacturing n-type and p-type semiconductors in diodes and transistors, junction surfaces are formed by diffusion treatment. However, sufficient time and temperature are required to form the bonding surface, and the thickness of the reaction layer formed increases with the formation of the bonding surface.

  In a pn junction doped with a large amount of impurities, the Fermi level of the p-type semiconductor is very high compared to the Fermi level of the n-type semiconductor, the height of the potential barrier generated at the junction is very large, and the diffusion potential difference is also large. Thus, the width of the forbidden band in the depletion layer becomes extremely thin. As a result, electrons are allowed to pass through the forbidden band due to the tunnel effect, indicating the properties of the tunnel (Ezaki) diode. Examples of the tunnel effect include a MOS junction and a pin junction.

  As the semiconductor material, there are Si, Ge, Se, Te, C and the like as a single substance. Examples of III-V semiconductors include GaAs, GaP, InAs, InP, InGaAs, AlGaAs, GaAsP, InGaN, AlGaN, AlGaInP, SiC, GaInNAs, and GaN, and II-VI semiconductors include ZnO, CdTe, and CdSe. ZnSe and the like.

  Examples of organic semiconductors include acene groups such as tethyracene and pentacene, and diamine derivatives such as oligothiophene derivatives, phthalocyanines, and pericin derivatives. Examples of the polymer include polythiophene such as poly (3-alkylthiophene), polyfluorene, polyphenylene vinylene, and polytriallylamine.

  The Josephson element is an electronic element using the Josephson effect (see Patent Document 1). The Josephson effect is a phenomenon in which a superconducting current flows between two weakly coupled superconductors by the tunnel effect of a superconducting electron pair. It can be said that it is the phenomenon that most clearly shows the characteristics of superconductivity in that a micro quantity of the phase of the wave function can be observed macroscopically. There are also important practical examples of quantum mechanical circuits based on the Josephson effect, such as a superconducting quantum interferometer (SQUID). The types of weak coupling include a tunnel junction, a submicron size bridge, a point contact, and the like. As the tunnel barrier, an insulator having a thickness of about 2 nm, a normal metal or a semiconductor having a thickness of about 10 nm are used. A superconducting current flowing through a weak coupling is called a Josephson current, and a tunnel junction exhibiting the Josephson effect is called a Josephson junction. When handled as an electronic device, it is called a Josephson element.

  Thermocouples and thermoelectric conversion elements that use the Seebeck effect are manufactured by joining different thermoelectric elements. A cooling element using the Pelcher effect is also manufactured by joining different thermoelectric elements.

In thermocouples, Cr, Co, Fe, Cu, Pt, Re, Ir, Rh, Pd, W, Ag, Au, and alloys such as alumel, chromel, and constantan are used. In the thermoelectric conversion element and the Pelcher element, in addition to the same material as the thermocouple, Bi—Sb alloy, In—Pb alloy, Se—Te alloy, Cd—Sb intermetallic compound, Bi—Te intermetallic compound, Se— A quaterdite-type compound such as Te solid solution or M _x Co ₄ Sb ₁₂ (M = Ge, Sb or Pb) is used. Further, the characteristics can be improved by doping impurities into these materials or changing the composition of these materials.

JP 2003-168831 A

  Conventionally, the formation of a reaction layer of a certain width or more is unavoidable on the junction surface between semiconductors of a junction diode or junction transistor or the junction surface of an electrode, which may deviate from the function of an ideal diode or transistor. there were.

Conventionally, in a semiconductor laser or a light emitting diode, it is inevitable to form a reaction layer having a certain width or more on a junction surface between semiconductors or an electrode junction surface. For this reason, an ideal interface or well-type potential cannot be formed, and the function of an ideal semiconductor laser or light emitting diode may be lost.

  When the reaction layer is thick at the junction interface, the tunnel effect is less likely to occur, and the function of the ideal tunnel diode or Josephson element may be lost. Examples of devices that require an ideal tunnel effect include MOS junctions and pin junctions.

  In a thermoelectric element, formation of a reaction layer having a width greater than a certain width is unavoidable on the bonding surface between a semiconductor and a metal or the bonding surface of an electrode, and the function of an ideal thermoelectric power is sometimes deviated. In thermocouples, the formation of a reaction layer having a certain width or more on the metal bonding surface is unavoidable, and the thermocouple may deviate from the ideal thermocouple function. In the Josephson element, the formation of a reaction layer having a certain width or more is unavoidable at the joint surface between the superconductors and the electrodes, and the function of the ideal Josephson element may be lost.

  In addition to vapor deposition and epitaxial bonding, thermal diffusion is used for bulk elements, but bonding may be insufficient depending on conditions.

  As described above, conventionally, the reaction layer becomes thick on the bonding surface, or the bonding becomes insufficient, and a desired function may not be obtained.

  The present invention has been made in view of such problems, and its purpose is to provide a functional material manufacturing method and a manufacturing method thereof capable of thinning a reaction layer or obtaining sufficient bonding on a bonding surface. It is to provide a manufactured functional material.

In the first functional material manufacturing method of the present invention, the first material and the second material made of a solid material different from the first material are in contact with or joined to each other. A high-gravity field that applies high gravity of at least 10,000 g (g = 9.8 m / s ² ) or more to the second material in a direction intersecting the contact surface or bonding surface with the second material of the first material. The processing is performed. Here, the first specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the first material is greater than the second specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the second material. Is larger, the high-gravity field process is performed after the first material is arranged on the gravity direction side in relation to the second material. When the first specific gravity equivalent amount is smaller than the second specific gravity equivalent amount, the high-gravity field process is performed after the second material is arranged on the gravity direction side in relation to the first material.

  The first functional material of the present invention is a thin film, plate or bulk functional material. This functional material is formed by the above-described first functional material manufacturing method.

  In the first functional material and the method for producing the same according to the present invention, when the first specific gravity equivalent amount is larger than the second specific gravity equivalent amount, the first material is arranged on the gravity direction side of the second material, and the first specific gravity is obtained. When the equivalent amount is smaller than the second specific gravity equivalent amount, the high-gravity field process is performed after the second material is arranged on the gravity direction side of the first material. Thereby, when the high gravity field process is performed in a state where the first material and the second material are in contact with each other, the material arranged on the side opposite to the direction of gravity is caused by the pressure generated by the gravity, and the gravity direction side The first material and the second material are bonded to each other at the contact surface. In addition, when high gravity field treatment is performed in a state where the first material and the second material are joined, gravity-induced diffusion occurs at the joining surface, so that an atom having a large specific gravity equivalent (atomic weight / atomic volume) is generated. Diffuses in the direction of gravity, and atoms with a small specific gravity equivalent (atomic weight / atomic volume) diffuse in the direction opposite to the direction of gravity. Thereby, atoms diffused by thermal diffusion are pulled back by gravity-induced diffusion, or thermal diffusion and gravity-induced diffusion antagonize. As a result, since thermal diffusion is suppressed or prevented, the concentration gradient of atoms becomes steep at the junction surface. When the gravity-induced diffusion rate is higher than the thermal diffusion rate at least under the same temperature condition, the concentration gradient of atoms becomes steeper at the junction surface. That is, the diffusion due to the concentration difference is suppressed by the high gravity field process.

The manufacturing method of the 2nd functional material of this invention consists of the material which contains the 1st material which consists of a solid material containing a 1st impurity, and the 2nd impurity different from a 1st impurity in the solid material different from a 1st material. With the second material in contact with or bonded to each other, the first material and the second material are at least 10,000 g in the direction intersecting the contact surface or bonding surface of the first material with the second material. g = 9.8 m / s ² ) or higher gravitational field treatment for applying high gravity. Here, the third specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the specific gravity of atoms of the first impurity is greater than the fourth specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the specific gravity of the atoms of the second impurity. Is larger, the high-gravity field process is performed after the first material is arranged on the gravity direction side in relation to the second material. When the third specific gravity equivalent amount is smaller than the fourth specific gravity equivalent amount, the high-gravity field process is performed after the second material is arranged on the gravity direction side in relation to the first material. The first impurity is, for example, an n-type impurity or a p-type impurity, and the second impurity is, for example, an impurity having a conductivity type different from that of the first impurity.

  The second functional material of the present invention is a thin film, plate or bulk functional material. This functional material is formed by the above-described second functional material manufacturing method.

  In the second functional material and the method of manufacturing the same according to the present invention, when the third specific gravity equivalent amount is larger than the fourth specific gravity equivalent amount, the first material is arranged on the gravity direction side of the second material, and the third specific gravity is obtained. When the equivalent amount is smaller than the fourth specific gravity equivalent amount, the high-gravity field process is performed after the second material is arranged on the gravity direction side of the first material. Thereby, when the high gravity field process is performed in a state where the first material and the second material are in contact with each other, the material arranged on the side opposite to the direction of gravity is caused by the pressure generated by the gravity, and the gravity direction side The first material and the second material are bonded to each other at the contact surface. In addition, when high gravity field treatment is performed in a state where the first material and the second material are joined, gravity-induced diffusion occurs at the joining surface, so that an atom having a large specific gravity equivalent (atomic weight / atomic volume) is generated. Diffuses in the direction of gravity, and atoms with a small specific gravity equivalent (atomic weight / atomic volume) diffuse in the direction opposite to the direction of gravity. Thereby, atoms diffused by thermal diffusion are pulled back by gravity-induced diffusion, or thermal diffusion and gravity-induced diffusion antagonize. As a result, since thermal diffusion is suppressed or prevented, the impurity concentration gradient becomes steep at the junction surface. When the gravity-induced diffusion rate is faster than the thermal diffusion rate at least under the same temperature condition, the impurity concentration gradient becomes steeper at the junction surface. That is, the diffusion due to the concentration difference is suppressed by the high gravity field process.

  In the first and second functional materials and the manufacturing methods thereof described above, the “junction” includes, for example, a pn junction, a pin junction, a heterojunction, a Schottky junction, a MOS junction, and the like. The same applies to the “joining” mentioned below. A pn junction is a junction between a p-type semiconductor and an n-type semiconductor, and a pin junction is a junction between a p-type semiconductor, an intrinsic semiconductor, and an n-type semiconductor. A heterojunction is a junction between semiconductors having different band gaps, a Schottky junction is a junction between a metal and a semiconductor, and a MOS junction is a junction between a metal, an insulator, and a semiconductor.

  In the first and second functional materials and the manufacturing methods thereof described above, the following materials can be used as the first material and the second material.

  For example, a simple substance of Si, Ge, Se, Te, or C can be used as the first material and the second material. The simple substance of C includes, for example, diamond, fullerene, nanotube, nano-onion, nanohorn, or graphite. Examples of III-V semiconductors include GaAs, GaP, InAs, InP, InGaAs, AlGaAs, GaAsP, InGaN, AlGaN, AlGaInP, SiC, GaInNAs, and GaN. Examples of the II-VI group semiconductor include ZnO, CdTe, CdSe, and ZnSe. When these materials are used as the first material and the second material, a semiconductor device such as a junction diode, a junction transistor, a semiconductor laser, or a light emitting diode can be manufactured by the above-described manufacturing method. It is.

  In addition, as the first material and the second material, it is possible to use low molecular weight materials, for example, diamine derivatives such as acene group such as tethyracene and pentacene, oligothiophene derivatives, phthalocyanines, and pericin derivatives. Further, as the first material and the second material, a polymer material such as polythiophene such as poly (3-alkylthiophene), polyfluorene, polyphenylene vinylene, polytriallylamine, or the like can be used. When these materials are used as the first material and the second material, for example, an organic semiconductor device can be manufactured by the manufacturing method described above.

  In addition, a superconductor can be used as at least one of the first material and the second material. When such a material is used as at least one of the first material and the second material, for example, a Josephson element can be manufactured by the manufacturing method described above.

  Further, as the first material and the second material, it is also possible to use alloys such as Cr, Co, Fe, Cu, Pt, Re, Ir, Rh, Pd, W, Ag, Au, alumel, chromel, constantan and the like. is there. When such materials are used as the first material and the second material, for example, a thermocouple, a thermoelectric conversion element, and a Peltier element can be manufactured by the manufacturing method described above.

Further, as the first material and the second material, all solid solution bismuth (Bi) -antimony (Sb) alloy, cadmium (Cd) -antimony intermetallic compound, bismuth-tellurium (Te) semiconductor compound (Bi _2). Te ₃ ), or a solid solution type selenium (Se) -tellurium-based semiconductor solid solution, or kutteudite type compounds such as M _x Co ₄ Sb ₁₂ (M = Ge, Sb or Pb) can be used. When such materials are used as the first material and the second material, for example, a thermoelectric conversion element or a Pelcher element can be manufactured by the above-described manufacturing method.

Further, in the first and second functional materials and the manufacturing methods thereof described above, at least 10,000 under a temperature condition that allows the first material and the second material to maintain a solid state in the high gravity field treatment. It is preferable to apply a gravitational acceleration of g (g = 9.8 m / s ² ) or more to the first material and the second material. This is because it is possible to cause gravity-induced diffusion. The gravitational acceleration is more preferably 100,000 g or more. This is because gravity-induced diffusion can be caused in many types of materials.

  Also, in high-gravity field processing, for example, the first material and the second material are installed in a rotor that can rotate at high speed around one axis, and then the rotor is rotated at a high speed and generated by the high-speed rotation. The centrifugal force to be applied can be applied to the first material and the second material as gravity. At this time, a plurality of planes that are parallel or inclined by a predetermined angle in relation to the rotation axis are provided in the rotor, and each plane is used as an installation surface (fixed surface) for installing (fixing) the first material and the second material. It is also possible to use it. Thereby, it is possible to easily apply gravity to the first material and the second material in a direction orthogonal to or intersecting with the contact surface or the joint surface. Further, since many first materials and second materials can be installed (fixed) in the rotor, it is possible to produce a large amount of functional materials at a time.

  In the case of using the rotor as described above, the first material and the second material can be heated through the rotor heated by contact heating, radiation heating or laser heating in the high gravity field treatment. It is. Regardless of whether or not the above-described rotor is used, it is also possible to directly heat the first material and the second material by contact heating, radiation heating or laser heating in the high-gravity field treatment.

  In addition, in the high gravity field treatment, from the viewpoint of increasing the diffusion coefficient, the temperature of the first material and the second material is equal to or higher than the recrystallization temperature of the first material and the second material, and the first material and the second material It is preferable that the two materials are in a temperature range below the temperature at which the solid state can be maintained. In the nanometer level diffusion such as the interface, the temperature of the first material and the second material may be lower than the recrystallization temperature of the first material and the second material (for example, about 300 ° C.). The temperature of the first material and the second material may be a temperature close to the recrystallization temperature of the first material and the second material, or a temperature close to the melting point temperature of the first material and the second material. Also good. The recrystallization temperature is usually about half the melting point (Kelvin).

  It is also possible to anneal the first material and the second material after performing the high gravity field treatment. This is because the crystalline state of the first material and the second material can be improved and the characteristics of the highly functional material can be improved by performing the annealing.

  According to the first and second functional materials of the present invention and the manufacturing method thereof, the first material and the second material are set in a predetermined positional relationship, and then high gravity field processing is performed on them. . Here, when the high-gravity field treatment is performed in a state where the first material and the second material are in contact with each other, the first material and the second material are bonded at the contact surface, so that sufficient bonding is obtained. Can do. In addition, the treatment time can be shortened as compared with the diffusion treatment at normal pressure, and the production can be performed at a lower temperature. On the other hand, when the high gravity field treatment is performed in a state where the first material and the second material are bonded, the concentration gradient of atoms or impurities diffused by thermal diffusion becomes steep, so that the reaction layer at the bonding surface Can be made thinner.

  Thus, in the present invention, sufficient bonding can be obtained, and the reaction layer can be thinned on the bonding surface, so that a desired function can be obtained easily and reliably. By thinning the reaction layer at the junction interface, an ideal function of an element such as a Zener diode, an avalanche diode, a pin diode, a tunnel diode, a Josephson element, or a MOS transistor can be reliably obtained. In addition, for example, an ideal thermoelectric function and a thermocouple function can be reliably obtained.

It is sectional drawing showing the example of 1 structure of the rotor used for the manufacturing method which concerns on one embodiment of this invention. It is sectional drawing showing the example of 1 structure of the sample of FIG. It is sectional drawing showing the other structural example of the sample of FIG.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The description will be given in the following order.

1. Embodiment (Case where high-gravity field treatment is applied to two types of materials)
2. Modification (Case where high-gravity field processing is applied to 3 or more materials)

<Embodiment>
FIG. 1A shows an example of a cross-sectional configuration of a high-gravity field generator used in a method for manufacturing a functional material according to an embodiment of the present invention. FIG. 1B illustrates an example of a cross-sectional configuration of the high-gravity field generating device in FIG.

[High gravity field generator]
First, a high gravity field generator will be described. This high-gravity field generating device can be suitably applied to a plate-like sample, and a rotor 10 capable of stably rotating at high speed for a long time around a single axis AX, and the rotor 10 as a shaft. And a drive unit (not shown) that rotates at high speed around AX. The rotor 10 has a point-symmetric shape around the axis AX in a plane orthogonal to the axis AX, and has, for example, a bell-like shape as shown in FIG. On the bottom surface of the rotor 10, an opening 10 </ b> A that communicates the internal space 10 </ b> B provided in the rotor 10 and the external space of the rotor 10 is provided. For example, as illustrated in FIGS. 1A and 1B, the internal space 10 </ b> B is surrounded by a polyhedral side surface having a plurality of flat surfaces (installation surfaces 10 </ b> C) parallel to the axis AX. The internal space 10B is further surrounded by a bottom surface 10D having a flat surface orthogonal to the axis AX or intersecting the installation surface 10C at an acute angle, and an upper surface 10E facing the bottom surface 10D and the opening 10A with a predetermined gap. It is a polygonal column space. The installation surface 10C is a surface on which the sample 20 is installed, and has a role of defining the direction of centrifugal force applied to the sample 20 when the rotor 10 is rotated. Further, the bottom surface 10D serves to prevent the sample 20 from falling off the installation surface 10C or slipping out to the outside when the sample 20 is installed on the installation surface 10C when the rotor 10 is stopped or rotated. Have. Therefore, this high-gravity field generating apparatus installs (fixes) the sample 20 at a predetermined position in the internal space 10B, and rotates the rotor 10 at a high speed with the axis AX as the central axis, thereby making a predetermined relative to the sample 20 It has a function of applying a centrifugal force in a direction (for example, a direction orthogonal to or intersecting with the axis AX). 1A illustrates the case where the bottom surface 10D has a flat surface orthogonal to the axis AX, the bottom surface 10D has a flat surface that intersects the installation surface 10C at an acute angle. May be. Further, for example, a structure such as a protrusion that positively prevents the sample 20 from falling off the installation surface 10C or sliding and jumping out may be provided on the bottom surface 10D.

This high-gravity field generator can apply a gravitational acceleration of at least 10,000 g (g = 9.8 m / s ² ) or more to the sample 20, and has a gravitational force of about 100,000 g or 1 million g. It is also possible to apply acceleration. That is, the high gravity field generator can generate gravity-induced diffusion described below in many types of materials. In addition, as shown in FIG. 1B, this high-gravity field generating apparatus can install (fix) the sample 20 on each installation surface 10C of the rotor 10, so that a large amount of functional materials can be produced at one time. It is also possible to do.

  In addition, although not shown in the drawing, this high-gravity field generator heats at least one of the rotor 10 and the sample 20 in both cases of rotation and non-rotation (for example, contact heating, radiation heating, laser heating, etc.). It has a heater that can do this. Here, when the rotor 10 itself is directly heated by the heater, the rotor 10 is made of a material that can transfer the heat of the rotor 10 to the sample 20 (for example, Inconel (resistant to high temperatures). Steel), Ti (titanium) -6Al (aluminum) -4V (vanadium) alloy, etc.). Further, when the sample 20 itself is directly heated by the heater, the rotor 10 is provided with a mechanism for transmitting the energy generated from the heater directly to the sample 20. The rotor 10 may include a cooler for cooling at least one of the rotor 10 and the sample 20 in addition to the heater.

[Sample 20]
Next, the sample 20 will be described. 2A and 2B show an example of a cross-sectional configuration of the sample 20 placed in the rotor 10. FIG. 2A and 2B illustrate a case where the sample 20 is disposed (fixed) so as to contact the side surface (installation surface 10C) and the bottom surface 10D of the internal space 10B. For example, as shown in FIGS. 2A and 2B, the sample 20 is obtained by contacting or joining solid materials 21 and 22 having different materials. A contact surface 20 </ b> A or a joint surface 20 </ b> B between the solid material 21 and the solid material 22 is parallel to the axis AX of the rotor 10 and is orthogonal to the rotation surface of the rotor 10.

  The above-mentioned “junction” includes, for example, a pn junction, a heterojunction, a Schottky junction, a pi junction or an in junction included in a pin junction, an MO junction or an OS junction included in a MOS junction, and the like. A pn junction is a junction between a semiconductor containing a p-type impurity and a semiconductor containing an n-type impurity. A heterojunction is a junction between semiconductors having different band gaps. A Schottky junction is a metal and a semiconductor. It is a joint with. A pin junction is a junction of a p-type semiconductor, an intrinsic semiconductor and an n-type semiconductor, a pi junction is a junction of a p-type semiconductor and an intrinsic semiconductor, and an in junction is an intrinsic semiconductor and an n-type semiconductor. It is a joint with. The MOS junction is a metal / insulator / semiconductor junction, the MO junction is a metal / insulator junction, and the OS junction is an insulator / semiconductor junction.

  When the solid materials 21 and 22 are in contact with each other, the solid materials 21 and 22 are joined at the contact surface 20A by the pressure generated by gravity. Further, when the solid materials 21 and 22 are bonded to each other, the thickness of the reaction layer (not shown) existing on the bonding surface 20B is reduced by gravity-induced diffusion when the solid materials 21 and 22 are bonded to each other. It is. The reaction layer is a layer existing at the boundary (bonding surface 20B) between the solid material 21 and the solid material 22.

  The reaction layer is, for example, a layer existing between a place where the concentration gradient of atoms contained in the solid material 21 starts to increase rapidly and a position where the concentration gradient of atoms contained in the solid material 22 starts to increase rapidly. It is. When the sample 20 is made of a pn junction semiconductor, the reaction layer exists between a place where the concentration gradient of the n-type impurity starts to increase rapidly and a position where the concentration gradient of the p-type impurity starts to increase rapidly. It is a layer to do.

  The solid materials 21 and 22 have a thin film shape, a plate shape, or a bulk shape. The solid materials 21 and 22 may be any materials that can be joined or materials that can cause gravity-induced diffusion, such as semiconductors, covalently bonded compounds, ionic compounds, organic substances, thermoelectric substances, and the like. It is constituted by. The solid materials 21 and 22 are made of, for example, a single crystal, a polycrystal, an amorphous, a polymer, a zeolite, an interlayer compound, a layered compound, or the like. The solid materials 21 and 22 may be a material system common to each other or may be a material system different from each other.

  Here, examples of the semiconductor include a single element of a group III, IV or V element, an alloy of a group III-V element, a transition element compound, a nitride, or a transition metal oxide. Examples of covalently bonded compounds and ionic compounds include strong correlation materials such as copper oxide superconductors and oxide giant magnetoresistive materials, perovskite oxides, and recent iron-based oxide superconductors (LnOMPn (Ln = lanthanum series). Element, M = transition metal, Pn = P, As or Sb) -based compounds), skutterudite-type compounds, and the like, and the like. At least one of the solid material 21 and the solid material 22 may be a superconductor.

  As the semiconductor, for example, a simple substance of Si, Ge, Se, Te, or C can be given. In addition to diamond, fullerenes, nanotubes, nano-onions, nanohorns, graphite, etc. are included in the simple substance of C. If impurities are added to these, peculiar semiconductor characteristics, superconducting characteristics, photocatalytic characteristics, batteries, etc. It is known to exhibit the function of Other semiconductors include III-V semiconductors mainly containing GaAs, GaP, InAs, InP, InGaAs, AlGaAs, GaAsP, InGaN, AlGaN, AlGaInP, SiC, GaInNAs, or GaN, ZnO, CdTe, CdSe, or ZeSe. The II-VI group semiconductor mainly contained is mentioned. When these materials are used as the solid materials 21 and 22, p-type impurities or n-type impurities may or may not be added to these materials. Moreover, when these materials are used as the solid materials 21 and 22, it is possible to manufacture semiconductor devices such as a junction diode, a junction transistor, a semiconductor laser, and a light emitting diode by a manufacturing method described later. It is.

  Examples of organic semiconductors include acene groups such as tethyracene and pentacene, and diamine derivatives such as oligothiophene derivatives, phthalocyanines, and pericin derivatives. Examples of the polymer include polythiophene such as poly (3-alkylthiophene), polyfluorene, polyphenylene vinylene, and polytriallylamine. When these materials are used as the solid materials 21 and 22, for example, an organic semiconductor device can be manufactured by a manufacturing method described later.

Thermoelectric materials can be improved in characteristics by doping impurities or changing the composition. Examples of thermoelectric materials include a solid solution bismuth (Bi) -antimony (Sb) alloy, a cadmium (Cd) -antimony intermetallic compound, a bismuth-tellurium (Te) semiconductor compound (Bi ₂ Te ₃ ), or Examples thereof include a solid solution type selenium (Se) -tellurium-based semiconductor solid solution. For example, ⁷⁶ Se, ⁷⁸ Se, ⁸⁰ Se and ⁸² Se of selenium (Se), ¹²⁵ Te, ¹²⁶ Te, ¹²⁸ Te and ¹³⁰ Te of tellurium (Te), ²⁸ Si, ²⁹ Si and ³⁰ Si of silicon (Si), etc. Is mentioned. Also included are kutteudite-type compounds such as M _x Co ₄ Sb ₁₂ (M = Ge, Sb or Pb). When these materials are used as the solid materials 21 and 22, for example, a thermoelectric conversion element or a Pelcher element can be manufactured by a manufacturing method described later.

  Further, Cr, Co, Fe, Cu, Pt, Re, Ir, Rh, Pd, W, Ag, Au, and alloys such as alumel, chromel, and constantan can be used as the solid materials 21 and 22. In this case, for example, a thermocouple, a thermoelectric conversion element, and a Pelcher element can be manufactured by a manufacturing method described later.

  Here, the first specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the solid material 21 is greater than the second specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the solid material 22. 2 is also preferable, for example, as shown in FIG. 2A, the solid material 21 is preferably arranged on the centrifugal force direction side (gravity direction side) in relation to the solid material 22. When the first specific gravity equivalent amount is smaller than the second specific gravity equivalent amount, for example, as shown in FIG. 2B, the solid material 22 has a centrifugal force direction side (in relation to the solid material 21). It is preferable to be arranged on the gravity direction side). In such a case, as will be described in detail later, the reaction layer formed on the contact surface 20A or the bonding surface 20B between the solid material 21 and the solid material 22 can be thinned. For example, when the above-described semiconductor is used as the solid materials 21 and 22 and the solid materials 21 and 22 include impurities (p-type impurities and n-type impurities), the following may be performed. preferable. That is, the third specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the specific gravity of atoms of the impurity (first impurity) contained in the solid material 21 is equal to that of the impurity (second impurity) contained in the solid material 22. In the case where it is larger than the fourth specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the specific gravity of the solid material 21, for example, as shown in FIG. It is preferable to arrange on the direction side (gravity direction side). When the third specific gravity equivalent amount is smaller than the fourth specific gravity equivalent amount, for example, as shown in FIG. 2B, the solid material 22 has a centrifugal force direction side (in relation to the solid material 21). It is preferable to be arranged on the gravity direction side). In such a case, as will be described in detail later, the reaction layer formed on the contact surface 20A or the bonding surface 20B between the solid material 21 and the solid material 22 can be thinned.

  Next, a processing procedure for the sample 20 will be described. In the following, the solid material 21 is composed of atoms with a large specific gravity equivalent (the first specific gravity equivalent), and the solid material 22 is composed of atoms with a small specific gravity equivalent (the second specific gravity equivalent). It shall be. Note that, for example, the above-described semiconductor is used as the solid materials 21 and 22, and the solid material 21 has a large specific gravity equivalent (the third specific gravity equivalent) impurity (p-type impurity or n-type impurity). And when the solid material 22 contains a small impurity equivalent to the specific gravity (the fourth specific gravity equivalent) (an impurity having a conductivity different from that of the impurity contained in the solid material 21). It holds.

  First, as shown in FIG. 2A, the solid material 21 is on the installation surface 10C side (centrifugal force direction side), and the solid material 22 is on the opposite side to the installation surface 10C (opposite side to the centrifugal force direction). The sample 20 is arranged (fixed) in the internal space 10B of the rotor 10 so as to be arranged.

Next, the rotor 10 is rotationally driven at high speed, and the centrifugal force generated by the high speed rotation is applied to the sample 20 as gravity. At this time, the direction of the centrifugal force faces the direction intersecting (orthogonal) with the contact surface 20 </ b> A of the sample 20. Further, the gravitational acceleration needs to be at least 10,000 g (g = 9.8 m / s ² ) or more, and preferably 100,000 g or more.

  As a result, when the high-gravity field process is performed in a state where the solid materials 21 and 22 are in contact with each other, the solid material 22 is pressed against the solid material 21 by the pressure generated by gravity, and the solid materials 21 and 22 are pressed. Are joined at the contact surface 20A.

  Further, when the high gravitational field process is performed in a state where the solid materials 21 and 22 are bonded to each other, gravity-induced diffusion occurs on the bonding surface 20B. As a result, atoms having a large specific gravity equivalent (atomic weight / atomic volume) (atoms or impurities contained in the solid material 21) diffuse in the direction of gravity (that is, the direction away from the solid material 22). On the other hand, atoms with small specific gravity equivalents (atomic weight / atomic volume) (atoms or impurities contained in the solid material 22) diffuse in the direction opposite to the direction of gravity (that is, the direction away from the solid material 21).

  Here, the gravity-induced diffusion rate is faster than the thermal diffusion rate at least under the same temperature condition. This is because the movement speed (drift speed) increases in proportion to the magnitude of gravity, or the diffusion coefficient increases due to the generation of many holes. In addition, under the high gravity field, it is thought that diffusion occurs due to a mechanism that has not yet been elucidated, and the gravity-induced diffusion rate is also increased due to the influence. Thereby, atoms diffused by thermal diffusion are pulled back by gravity-induced diffusion, or thermal diffusion and gravity-induced diffusion antagonize. As a result, since thermal diffusion is suppressed or prevented, the concentration gradient of atoms becomes steep at the junction surface. When the gravity-induced diffusion rate is higher than the thermal diffusion rate at least under the same temperature condition, the concentration gradient of atoms becomes steeper at the junction surface. That is, the diffusion due to the concentration difference is suppressed by the high gravity field process.

  In addition, it is preferable to heat or cool the sample 20 with the above-described high-gravity field treatment. The sample 20 may be heated directly by a heater, or may be indirectly heated via the rotor 10 heated by the heater. For example, in high gravity field processing, from the viewpoint of increasing the diffusion coefficient, the temperature of the solid materials 21 and 22 is equal to or higher than the recrystallization temperature of the solid materials 21 and 22 and the solid materials 21 and 22 are in a solid state. It is preferable to heat the sample 20 so as to be within a temperature range equal to or lower than the temperature at which the temperature can be maintained. In the nanometer-level diffusion such as the interface, the temperature of the solid materials 21 and 22 may be lower than the recrystallization temperature of the solid materials 21 and 22 (for example, about 300 ° C.). The temperature of the solid materials 21 and 22 may be a temperature close to the recrystallization temperature of the solid materials 21 and 22 or may be a temperature close to the melting point temperature of the solid materials 21 and 22. The recrystallization temperature is usually about half the melting point (Kelvin).

  In addition, as the solid materials 21 and 22, a thin plate material or a thin film material having a single layer or a multilayer structure having a thickness of 2 mm or less may be used, or a thin film material having a thickness of 100 μm or less may be used. It is of course possible to use a bulk material (typically a material having a thickness exceeding 2 mm) as the solid material 21.

  By the way, it is preferable to anneal the sample 20 (solid materials 21 and 22) as necessary after performing the above-described high-gravity field treatment. By annealing, the crystal state of the solid materials 21 and 22 can be improved, and the characteristics of the solid materials 21 and 22 can be improved.

[Action / Effect]
Thus, in the method for producing a functional material according to the present embodiment, when the first specific gravity equivalent amount is larger than the second specific gravity equivalent amount, the solid material 21 is arranged on the gravity direction side of the solid material 22, and When the amount corresponding to the specific gravity is smaller than the amount corresponding to the second specific gravity, the high-gravity field process is performed after the solid material 22 is arranged on the gravity direction side of the solid material 21. Alternatively, when the third specific gravity equivalent amount is larger than the fourth specific gravity equivalent amount, the solid material 21 is arranged on the gravity direction side with respect to the solid material 22, and the third specific gravity equivalent amount is smaller than the fourth specific gravity equivalent amount. In this case, the high-gravity field process is performed after the solid material 22 is arranged on the gravity direction side of the solid material 21. As a result, when the high gravity field processing is performed in a state where the solid materials 21 and 22 are in contact with each other, the material disposed on the opposite side to the gravity direction causes the pressure generated by the gravity to move toward the gravity direction side. The solid materials 21 and 22 are bonded to each other at the contact surface 20A by being pressed against the arranged material. As a result, sufficient bonding can be obtained at the contact surface 20A, and a reaction layer is formed on the bonding surface. In addition, the treatment time can be shortened as compared with the diffusion treatment at normal pressure, and the production can be performed at a lower temperature.

  Further, when the high-gravity field treatment is performed in a state where the solid materials 21 and 22 are bonded to each other, gravity-induced diffusion occurs on the bonding surface 20B, and thus an atom having a large specific gravity equivalent (atomic weight / atomic volume). Alternatively, impurities diffuse in the direction of gravity, and atoms or impurities with a small specific gravity equivalent (atomic weight / atomic volume) diffuse in the direction opposite to the direction of gravity. Here, since the gravity-induced diffusion rate is faster than the thermal diffusion rate at least under the same temperature condition, the atoms diffused by thermal diffusion are pulled back by gravity-induced diffusion, and thermal diffusion and gravity-induced diffusion Antagonize. Thereby, since thermal diffusion is suppressed or prevented, the concentration gradient of atoms or impurities becomes steep at the junction surface. As a result, the reaction layer can be thinned or eliminated at the bonding surface 20B. For example, the thickness of the reaction layer on the bonding surface 20B can be 1 nm or less, 10 nm or less, or 100 nm or less. Further, for example, the thickness of the reaction layer on the bonding surface 20B can be set to be 1 atomic layer or more and 10 atomic layer or less, or can be set to a thickness causing a tunnel effect.

  As described above, in the present embodiment, sufficient bonding can be obtained on the contact surface 20A, and the reaction layer can be thinned or eliminated on the bonding surface 20B. You can definitely get it. By thinning the reaction layer at the junction interface, an ideal function of an element such as a Zener diode, an avalanche diode, a pin diode, a tunnel diode, a Josephson element, or a MOS transistor can be reliably obtained. In addition, for example, an ideal thermoelectric function and a thermocouple function can be reliably obtained. In the manufacturing method of the present embodiment, since the thickness of the reaction layer can be set to, for example, 1 atomic layer or more and 10 atomic layers or less, a new function can be imparted to the element. is there.

  From the above, in this embodiment, it is possible to manufacture not only a functional material that can be manufactured by a conventional method but also a functional material that is difficult to manufacture by a conventional method.

  Moreover, in the high gravity field generator used in the manufacturing method of the present embodiment, the site (installation surface 10C) where the sample 20 is installed is a flat surface. Therefore, it is possible to process a larger sample than a conventional apparatus using a cylindrical sample capsule, and it is possible to process a large amount of samples at a time. Therefore, by using this high gravitational field generator, high productivity can be obtained and the production cost can be greatly reduced.

<Modification>
In the above embodiment, two kinds of materials (solid materials 21 and 22) are contacted or joined and then subjected to high-gravity field treatment, but three or more kinds of materials are contacted or joined. Thus, high-gravity field processing may be performed on these. For example, as shown in FIG. 3A, a solid material 23 different from the solid material 21 is disposed on the gravity direction side, and in contact with or bonded to the solid material 21, two kinds of materials (solid material 21) are arranged. , 22) may be contacted or joined and then subjected to a high gravity field treatment.

  At this time, when the specific gravity equivalent (atomic weight / atomic volume) of the solid material 23 corresponding to the specific gravity of atoms is larger than the specific gravity equivalent (atomic weight / atomic volume) of the solid material 21 corresponding to the specific gravity of atoms. Can thin the reaction layer formed on the contact surface between the solid material 21 and the solid material 23 or the reaction layer formed on the bonding surface. Conversely, when the specific gravity equivalent (atomic weight / atomic volume) of the solid material 23 corresponding to the specific gravity of atoms is smaller than the specific gravity equivalent (atomic weight / atomic volume) of the solid material 21 corresponding to the specific gravity of atoms. Can thicken the reaction layer formed on the contact surface of the solid material 21 and the solid material 23 or the reaction layer formed on the bonding surface. For example, the thickness of the reaction layer can be increased to 10 nm or more, 100 nm or more, 1 μm or more, or 10 μm or more. For example, when the above-described semiconductor is used as the solid materials 21 and 23 and the solid materials 21 and 23 contain impurities, the following can be performed. That is, the specific gravity equivalent amount (atomic weight / atomic volume) of the impurities contained in the solid material 23 corresponds to the specific gravity equivalent (atomic weight / atom) of the impurities contained in the solid material 21. If it is larger than the above, the reaction layer formed on the contact surface between the solid material 21 and the solid material 23 or the reaction layer formed on the bonding surface can be thinned. On the contrary, the specific gravity equivalent amount (atomic weight / atomic volume) of the impurities contained in the solid material 23 corresponds to the specific gravity equivalent (atomic weight / atomic volume) of the impurities contained in the solid material 21. If it is smaller than (atomic capacity), the reaction layer formed on the contact surface between the solid material 21 and the solid material 23 or the reaction layer formed on the bonding surface can be thickened. For example, the thickness of the reaction layer can be increased to 10 nm or more, 100 nm or more, 1 μm or more, or 10 μm or more.

  Further, for example, as shown in FIG. 3B, a solid material 24 different from the solid material 22 is arranged on the side opposite to the direction of gravity, and in contact with or joined to the solid material 22, After the materials (solid materials 21 and 22) are contacted or joined, high-gravity field treatment may be performed on them.

  At this time, when the specific gravity equivalent (atomic weight / atomic volume) of the solid material 24 corresponding to the specific gravity of atoms is larger than the specific gravity equivalent (atomic weight / atomic volume) of the solid material 22 corresponding to the specific gravity of atoms. The thickness of the reaction layer formed on the contact surface between the solid material 22 and the solid material 24 or the reaction layer formed on the bonding surface can be increased. For example, the thickness of the reaction layer can be increased to 10 nm or more, 100 nm or more, 1 μm or more, or 10 μm or more. On the contrary, when the specific gravity equivalent (atomic weight / atomic volume) of the solid material 24 corresponding to the specific gravity of atoms is smaller than the specific gravity equivalent (atomic weight / atomic volume) of the solid material 22 corresponding to the specific gravity of atoms. Can thin the reaction layer formed on the contact surface between the solid material 22 and the solid material 24 or the reaction layer formed on the bonding surface. Further, for example, when the above-described semiconductor is used as the solid materials 22 and 24 and the solid materials 22 and 24 contain impurities, the following is possible. That is, the specific gravity equivalent amount (atomic weight / atomic volume) of the impurities contained in the solid material 24 corresponds to the specific gravity equivalent (atomic weight / atom) of the impurities contained in the solid material 22. If it is larger than the above, the reaction layer formed on the contact surface between the solid material 22 and the solid material 24 or the reaction layer formed on the bonding surface can be thickened. For example, the thickness of the reaction layer can be increased to 10 nm or more, 100 nm or more, 1 μm or more, or 10 μm or more. On the contrary, the specific gravity equivalent amount (atomic weight / atomic volume) of the impurities contained in the solid material 24 is equivalent to the specific gravity equivalent (atomic weight / atomic volume) of the impurities contained in the solid material 22. If it is smaller than the atomic volume, the reaction layer formed on the contact surface between the solid material 22 and the solid material 24 or the reaction layer formed on the bonding surface can be made thin.

  As described above, when three or more kinds of materials are contacted or bonded and then subjected to high-gravity field treatment, for example, a MOS junction, a pin junction, a pnp junction, an npn junction, a thyristor, etc. It can be produced. Further, when the reaction layer is formed on the contact surface between the solid material 21 and the solid material 22 or the reaction layer formed on the joint surface between the solid material 21 and the solid material 22 is thinned by the high gravity field treatment. In addition, it is possible to increase or decrease the thickness of the reaction layer present on the bonding surface between the solid material 21 and the solid material 23 and the bonding surface between the solid material 22 and the solid material 24.

  In the above embodiment, the installation surface 10C of the rotor 10 is a plane parallel to the axis AX1 (rotation axis), but the inclined surface is inclined by a predetermined angle with respect to the axis AX1 (rotation axis). It may be. In the above embodiment, the rotor 10 as shown in FIG. 1A is used to perform the high-gravity field processing on the sample 20, but other devices (for example, Japanese Patent Laid-Open No. 2003-2003) are used. Conventionally used devices such as those described in Japanese Patent No. 103199 and Japanese Patent Laid-Open No. 9-290178 may be used.

  Further, in the above-described embodiment, the case where the opening 10A of the rotor 10 is directed vertically downward is illustrated, but the opening 10A may be directed vertically upward, or may be directed horizontally. . However, when the opening 10A faces vertically upward, the upper surface 10E in the above embodiment functions as a bottom surface, and when the opening 10A faces sideways, the side surface (installation surface 10C in the above embodiment). ) Functions as the bottom.

  DESCRIPTION OF SYMBOLS 10 ... Rotor, 10A ... Opening, 10B ... Internal space, 10C ... Installation surface, 10D ... Bottom surface, 10E ... Upper surface, 20 ... Sample, 20A ... Contact surface, 21,22 ... Solid material, AX ... Shaft.

Claims (17)

A first material made of a solid material and a second material made of a solid material different from the first material are brought into contact with or joined to each other, and a first specific gravity equivalent amount corresponding to the specific gravity of atoms of the first material ( When the atomic weight / atomic volume) is larger than the second specific gravity equivalent (atomic weight / atomic volume) corresponding to the specific gravity of the atom of the second material, the first material is related to the second material. Is arranged on the gravity direction side, and when the first specific gravity equivalent amount is smaller than the second specific gravity equivalent amount, the second material is arranged on the gravity direction side in relation to the first material, With respect to the first material and the second material, at least 10,000 g (g = 9.8 m / s ² ) or more in the direction intersecting the contact surface or the bonding surface with the second material of the first material. function material and performing high-gravity field process of applying the high gravity Manufacturing method. A first material made of a solid material containing a first impurity, and a second material made of a material containing a second impurity different from the first impurity in contact with or joined to a solid material different from the first material The third specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the first impurity is greater than the fourth specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the second impurity. Is larger, the first material is disposed in the direction of gravity in relation to the second material, and when the third specific gravity equivalent is smaller than the fourth specific gravity equivalent, In relation to the material, after the second material is arranged on the gravity direction side, the contact surface or the joint surface with the second material of the first material with respect to the first material and the second material At least 10,000 g in a direction crossing (g = 9.8 m / Method for producing a functional material which is characterized in that the high-gravity field processing to apply a ²⁾ or more high-gravity. The first material and the second material are joined by performing the high-gravity field treatment in a state where the first material and the second material are in contact with each other. A method for producing the functional material described. By performing the high-gravity field treatment, gravity-induced diffusion is caused inside both the first material and the second material, and diffusion due to a concentration difference is controlled by the gravity-induced diffusion. The manufacturing method of the functional material of Claim 1 or Claim 2. The first material and the second material have a reaction layer on their joint surfaces,
The function according to claim 1 or 2, wherein the thickness of the reaction layer is reduced by performing the high-gravity field treatment in a state where the first material and the second material are joined. Material manufacturing method. The method for producing a functional material according to claim 5, wherein the reaction layer is formed to have a thickness causing a tunnel effect by the high gravity field treatment. In a state where a third material different from the first material is bonded to the first material, or in a state where a fourth material different from the second material is bonded to the second material, the high gravity field treatment is performed. The method for producing a functional material according to claim 1, wherein the method is performed. The reaction layer existing on the joint surface between the first material and the third material or the joint surface between the second material and the third material is thickened by the high-gravity field treatment. A method for producing the functional material described in 1. The method for producing a functional material according to claim 1, wherein at least one of the first material and the second material is a superconductor. The first material and the second material may be a simple substance of Si, Ge, Se, Te, or C, GaAs, GaP, InAs, InP, InGaAs, AlGaAs, GaAsP, InGaN, AlGaN, AlGaInP, SiC, GaInNAs or The functional material according to claim 1, wherein the functional material is a group III-V semiconductor mainly containing GaN or a group II-VI semiconductor mainly containing ZnO, CdTe, CdSe, or ZeSe. Manufacturing method. The first material and the second material are all solid solution bismuth (Bi) -antimony (Sb) alloy, cadmium (Cd) -antimony intermetallic compound, bismuth-tellurium (Te) semiconductor compound (Bi _{2). 3. The} method for producing a functional material according to claim 1, wherein the functional material is Te ₃ ), a total solid solution type selenium (Se) -tellurium-based semiconductor solid solution, or a Kutteldite type compound. The first material and the second material are alloys of Cr, Co, Fe, Cu, Pt, Re, Ir, Rh, Pd, W, Ag, Au, alumel, chromel, constantan and the like. The manufacturing method of the functional material of Claim 1 or Claim 2 to do. 3. The method for producing a functional material according to claim 1, wherein the high-gravity field treatment is set to a temperature lower than a melting point temperature of the first material and the second material. 3. The method for producing a functional material according to claim 1, wherein the high-gravity field treatment is set to a temperature lower than a recrystallization temperature of the first material and the second material. The method for producing a functional material according to claim 1, wherein the first material and the second material are heated or cooled in the high-gravity field treatment. A thin film, plate or bulk functional material,
The functional material is
A first material made of a solid material and a second material made of a solid material different from the first material are brought into contact with or joined to each other, and a first specific gravity equivalent amount corresponding to the specific gravity of atoms of the first material ( When the atomic weight / atomic volume) is larger than the second specific gravity equivalent (atomic weight / atomic volume) corresponding to the specific gravity of the atom of the second material, the first material is related to the second material. Is arranged on the gravity direction side, and when the first specific gravity equivalent amount is smaller than the second specific gravity equivalent amount, the second material is arranged on the gravity direction side in relation to the first material, With respect to the first material and the second material, at least 10,000 g (g = 9.8 m / s ² ) or more in the direction intersecting the contact surface or the bonding surface with the second material of the first material. characterized in that formed by applying a high gravity Functional material. A thin film, plate or bulk functional material,
The functional material is
A first material made of a solid material containing a first impurity, and a second material made of a material containing a second impurity different from the first impurity in contact with or joined to a solid material different from the first material The third specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the first impurity is greater than the fourth specific gravity equivalent amount (atomic weight / atomic volume) corresponding to the atomic specific gravity of the second impurity. Is larger, the first material is disposed in the direction of gravity in relation to the second material, and when the third specific gravity equivalent is smaller than the fourth specific gravity equivalent, In relation to the material, after the second material is arranged on the gravity direction side, the contact surface or the joint surface with the second material of the first material with respect to the first material and the second material At least 10,000 g in a direction crossing (g = 9.8 m / Functional materials, characterized in that one formed by applying a ²⁾ or more high-gravity.

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