WO2011148686A1 - Method for production of thermoelectric conversion module, and thermoelectric conversion module - Google Patents

Method for production of thermoelectric conversion module, and thermoelectric conversion module Download PDF

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WO2011148686A1
WO2011148686A1 PCT/JP2011/055075 JP2011055075W WO2011148686A1 WO 2011148686 A1 WO2011148686 A1 WO 2011148686A1 JP 2011055075 W JP2011055075 W JP 2011055075W WO 2011148686 A1 WO2011148686 A1 WO 2011148686A1
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semiconductor element
type semiconductor
thermoelectric conversion
metal oxide
conversion module
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French (fr)
Japanese (ja)
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圭史 西尾
努 飯田
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学校法人東京理科大学
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Definitions

  • the present invention relates to a method for manufacturing a thermoelectric conversion module and a thermoelectric conversion module.
  • Thermoelectric conversion refers to the mutual conversion of thermal energy and electrical energy using the Seebeck effect or Peltier effect. If thermoelectric conversion is used, it is possible to extract electric power from the heat flow using the Seebeck effect.
  • thermoelectric conversion is direct conversion, it has characteristics such that excess waste products are not discharged during energy conversion, and effective use of exhaust heat is possible. For this reason, research on thermoelectric conversion modules has been actively conducted.
  • thermoelectric conversion modules have a so-called ⁇ -type structure.
  • the ⁇ -type structure includes an n-type semiconductor element, a p-type semiconductor element (hereinafter, the n-type semiconductor element and the p-type semiconductor element may be collectively referred to as “semiconductor element”), one end of the n-type semiconductor element, A common electrode to which one end of the p-type semiconductor element is joined, and an electrode to be joined independently to the other end of the n-type semiconductor element and the other end of the p-type semiconductor element (hereinafter, the common electrode and the electrode are combined) It may be referred to as “electrode etc.”).
  • thermoelectric conversion module having a ⁇ -type structure In the manufacture of a thermoelectric conversion module having a ⁇ -type structure, a method using a paste (see Patent Document 1) and a method using solder (see Patent Document 2) are employed as a bonding method between a semiconductor element and an electrode. Neither the method using paste nor the method using solder is satisfactory in terms of productivity because it is necessary to bond a semiconductor element and an electrode for each ⁇ -type thermoelectric conversion module. Therefore, in order to increase the productivity of the thermoelectric conversion module having a ⁇ -type structure, a method of manufacturing a plurality of thermoelectric conversion modules having a ⁇ -type structure at the same time is desired. However, there is currently no such method. is there.
  • thermoelectric conversion module in the power generation by the thermoelectric conversion module, it is desirable to use the waste heat from the incinerator or industrial furnace as it is.
  • the heat resistance of the thermoelectric conversion module becomes a problem, and when the waste heat reaches about 600 ° C., it is difficult to generate power.
  • thermoelectric conversion module that can be used in a high temperature environment of about 600 ° C. requires improvement of heat resistance of p-type semiconductor elements and n-type semiconductor elements. Although development of a thermoelectric conversion module with high heat resistance is underway (see Patent Document 3), no thermoelectric conversion module having sufficient heat resistance and high power generation performance has been developed.
  • the present invention has been made to solve the above-described problems, and has as its object to provide a method for manufacturing a thermoelectric conversion module with high productivity, and a thermoelectric conversion that can be used in a high temperature environment and has high power generation performance. To provide a module.
  • thermoelectric conversion module n-type conductive metal oxide powder or p-type conductive metal oxide powder
  • the productivity of the thermoelectric conversion module is increased by joining the electrodes and the like by a specific method, and further, the power generation performance of the thermoelectric conversion module is improved by using the metal powder and the conductive metal oxide powder in combination. I also found a dramatic improvement.
  • thermoelectric conversion module can be used in a high temperature environment. It has also been found that this is possible, and further, it has also been found that the power generation performance of the thermoelectric conversion module is drastically improved by selecting the material constituting the thermoelectric conversion module.
  • the present invention has been made on the basis of such findings, and is specifically as follows.
  • thermoelectric conversion module comprising: an electrode that is independently joined to the other end of the type semiconductor element; and a metal powder and / or between the n type semiconductor element and the common electrode and the electrode An n-type conductive metal oxide powder is disposed, a metal powder and / or a p-type conductive metal oxide powder is disposed between the p-type semiconductor element and the common electrode, and the n-type semiconductor element.
  • thermoelectric conversion module of joining between the common electrode and the electrode and the p-type semiconductor element.
  • thermoelectric conversion module (2)
  • the metal powder and / or the n-type conductive metal oxide powder and the metal powder and / or the p-type conductive metal oxide powder are green compacts of the thermoelectric conversion module according to (1). Production method.
  • thermoelectric conversion module as described in (1) or (2) which arrange
  • the p-type semiconductor element is a sintered body mainly composed of a metal oxide different from the p-type conductive metal oxide used for joining the common electrode and the electrode, and the n-type semiconductor
  • the element is any one of (1) to (3) which is a sintered body containing magnesium silicide as a main component or containing magnesium silicide as a main component and containing at least one element selected from Sb and Al as a dopant.
  • the p-type semiconductor element applies a DC pulse current parallel to the pressing direction while uniaxially pressing a mixture of the metal oxide powder and the metal oxide plate crystal.
  • thermoelectric conversion module comprising a bonded body, a sintered body of a mixture of a metal and an n-type conductive metal oxide, or a sintered body of an n-type conductive metal oxide.
  • thermoelectric conversion module according to (6), wherein a joint between the common electrode and the electrode is formed of a sintered body of a mixture of a metal and an n-type conductive metal oxide.
  • the p-type semiconductor element is a sintered body whose main component is a metal oxide different from the p-type conductive metal oxide constituting the junction, and the n-type semiconductor element is mainly made of magnesium silicide.
  • thermoelectric conversion module according to (8), wherein the sintered body containing magnesium silicide as a main component includes a dopant.
  • thermoelectric conversion module according to (9), wherein the dopant is at least one element selected from Sb and Al.
  • the metal oxide constituting the p-type semiconductor element is selected from Na x CoO 2 , CaCo 2 O 4 , CuYO 2 , SrRuO 3 , and Sr 2 RuO 4 (8) to (10)
  • the thermoelectric conversion module of any one is selected from Na x CoO 2 , CaCo 2 O 4 , CuYO 2 , SrRuO 3 , and Sr 2 RuO 4 (8) to (10)
  • the p-type conductive metal oxide constituting the sintered body of the joint is selected from SrRuO 3 , ReO 3 , Cu 2 O and CuO, according to any one of (6) to (11) Thermoelectric conversion module.
  • the n-type conductive metal oxide constituting the sintered body of the joint is In 2 O 3 , SnO 2 , In 2 O 3 —SnO 2 , or Nb or La-doped SrTiO 3 , ZnO (6
  • the thermoelectric conversion module according to any one of (12) to (12).
  • thermoelectric conversion module of the present invention According to the method for manufacturing a thermoelectric conversion module of the present invention, a plurality of ⁇ -type thermoelectric conversion modules can be manufactured at a time. For this reason, compared with the manufacturing method of the conventional thermoelectric conversion module of the above-mentioned pi type structure, the manufacturing method of the thermoelectric conversion module of the present invention has high productivity.
  • thermoelectric conversion module having high power generation performance is obtained.
  • a conductive metal oxide is used in combination, the performance is dramatically improved.
  • thermoelectric conversion module of the present invention preferably uses a p-type semiconductor element and an n-type semiconductor element that have high heat resistance, and thus the obtained thermoelectric conversion module can be used in a high temperature environment.
  • thermoelectric conversion module of the present invention when a specific metal oxide is used as the p-type semiconductor element of the thermoelectric conversion module of the present invention, the power generation performance of the thermoelectric return module is greatly enhanced.
  • thermoelectric conversion module of Example 1 It is a figure which shows typically the thermoelectric conversion module manufactured with the method of this invention. It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 1.
  • FIG. It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 2.
  • FIG. It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 3.
  • FIG. It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 4.
  • FIG. It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 5.
  • FIG. It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 6.
  • FIG. 1 is a schematic diagram of a thermoelectric conversion module according to the present invention, in which an n-type semiconductor element 10, a p-type semiconductor element 11, a common electrode at which one end of an n-type semiconductor element and one end of a p-type semiconductor element are joined. 12 and an electrode 13 that is independently joined to the other end of the n-type semiconductor element and the other end of the p-type semiconductor element.
  • an n-type semiconductor element 10 a p-type semiconductor element 11
  • a common electrode at which one end of an n-type semiconductor element and one end of a p-type semiconductor element are joined.
  • 12 and an electrode 13 that is independently joined to the other end of the n-type semiconductor element and the other end of the p-type semiconductor element.
  • thermoelectric conversion module ⁇ N-type semiconductor element> It does not specifically limit as an n-type semiconductor element which comprises the thermoelectric conversion module of this invention, The conventionally well-known n-type semiconductor element used for a thermoelectric conversion module can be used.
  • magnesium silicide Mg 2 Si
  • WO2011 / 013609A1 it is preferable to use those disclosed in WO2011 / 013609A1.
  • Magnesium silicide shown in the international number WO2011 / 002035A1 has a melting point of 1358K, a linear expansion coefficient of 15.5 ⁇ 10 ⁇ 6 / K (293 ° C.), is thermally stable, and has high thermoelectric conversion efficiency.
  • magnesium silicide has a Young's modulus of about 120 GPa and has excellent rigidity.
  • Magnesium silicide can contain a dopant selected as necessary. Although it does not specifically limit as a dopant contained in magnesium silicide, For example, when Sb, Al, etc. are used, it is effective in reducing an electrical resistivity or improving durability.
  • the content of the dopant is not particularly limited, but is preferably 0.1 to 1% by mass. It is particularly preferable to use magnesium silicide containing Sb as a dopant as the n-type semiconductor element.
  • the method for producing magnesium silicide is not particularly limited, but, for example, the method described in the above-mentioned international publication proposed by the present inventors is preferable, and can be performed by the following procedure. First, using magnesium (Mg) and silicon (Si) as raw materials, both are mixed, melted and reacted to synthesize magnesium silicide, pulverized into powder, and then this powder is sintered to form n-type A desired magnesium silicide useful as a thermoelectric conversion element can be obtained.
  • Mg magnesium
  • Si silicon
  • magnesium silicide powder when magnesium silicide is synthesized using magnesium and silicon as raw materials, the synthesis temperature is higher than the melting point of magnesium silicide (1358 K) (for example, 1370 to 1400 K). A method of synthesizing the whole as a melt is preferred. This is because uniform magnesium silicide can be obtained.
  • the obtained magnesium silicide is pulverized to form magnesium silicide powder.
  • the average particle diameter of the magnesium silicide powder is not particularly limited, but is preferably adjusted to, for example, 25 to 100 ⁇ m.
  • a conventionally known method such as a hot press sintering method, a hot isostatic pressing method, or a discharge plasma sintering method can be employed.
  • a discharge plasma sintering method it is most preferable to employ a discharge plasma sintering method. This is because a dense sintered body can be obtained in a short time.
  • Discharge plasma sintering is a method of obtaining a sintered body by applying a DC pulse current in a direction parallel to the pressing direction while uniaxially pressing magnesium silicide powder.
  • spark plasma sintering can be performed by the following method using a conventionally known apparatus. First, a mold filled with a sample is set on a sintering stage in a chamber, sandwiched between graphite electrodes, and pulsed while conducting pressure. Next, the temperature of the sample is rapidly raised from room temperature to 700 to 2500 ° C. within a few minutes. Finally, the sample is held for several minutes at the temperature after the temperature rise to obtain a sintered body.
  • the rate of temperature rise affects the quality of magnesium silicide. It is preferable to set 600 ° C. or less at a temperature increase rate of 80 to 120 ° C./min, 600 to 700 ° C. at a temperature increase rate of 40 to 60 ° C./min, and 700 ° C. or more at a temperature increase rate of 20 to 40 ° C./min.
  • the other conditions are preferably set such that the pressure is 20 to 70 MPa, the temperature after the temperature rise is 700 to 900 ° C., and the holding time is 30 seconds to 15 minutes.
  • thermoelectric conversion module The p-type semiconductor element which comprises the thermoelectric conversion module of this invention is not specifically limited, The conventionally well-known p-type semiconductor used for a thermoelectric conversion module can be used. In particular, it is preferable to use a sintered body containing a metal oxide as a main component as a p-type semiconductor element.
  • the “main component” means that other components may be contained in the p-type semiconductor element as long as the effects of the present invention are not impaired.
  • the metal oxide examples include Na x CoO 2 , CaCo 2 O 4 , CuYO 2 , SrRuO 3 , and Sr 2 RuO 4 .
  • CuYO 2 may be doped with a divalent alkaline earth metal such as Ca, Mg, Sr, etc., or oxygen may be excessive to form CuYO 2 + x .
  • SrRuO 3 and Sr 2 RuO 4 Nb may be doped.
  • a p-type semiconductor element mainly containing SrRuO 3 is preferable. This is because the junction between the electrode and the p-type semiconductor element tends to be in ohmic contact.
  • metal oxide is excellent in heat resistance, it is preferable as a p-type semiconductor element used in a thermoelectric conversion module used in a high temperature environment.
  • the metal oxide sintered body can be manufactured by the following procedure. First, metal oxide powder is prepared using a metal organic compound or an inorganic compound as a raw material. The powder is then sintered.
  • the metal oxide powder can be prepared by a conventionally known method starting from a solution containing a metal element, such as a sol-gel method, a thermal decomposition method of a metal-organic complex, or a coprecipitation method.
  • the sol-gel method is a solution in which a starting material such as a metal organic compound or inorganic compound is dissolved in a solvent to cause a chemical reaction such as hydrolysis or polycondensation in the solution. This is a method of forming a sol solution in which oxide fine particles are dissolved.
  • a gelled product in which the sol solution is aggregated is formed.
  • the gelled product is heat-treated to remove the solvent remaining inside, an aggregate of metal oxide fine particles is obtained.
  • the aggregate is pulverized to obtain a metal oxide powder.
  • the method for sintering the metal oxide powder is not particularly limited, and examples thereof include a hot press sintering method, a hot isostatic pressing method, and a discharge plasma sintering method.
  • a hot press sintering method a hot press sintering method
  • a hot isostatic pressing method a hot isostatic pressing method
  • a discharge plasma sintering method it is most preferable to employ a discharge plasma sintering method. This is because a dense sintered body can be obtained in a short time.
  • some metal oxide crystals are anisotropic in electrical resistivity.
  • a metal oxide sintered body is manufactured by the following method.
  • a metal oxide powder is prepared using a conventionally known method such as a sol-gel method or a coprecipitation method.
  • a plate-like crystal is produced from the metal oxide powder using, for example, a flux method.
  • the flux refers to a solvent, and is a generic name for substances used as a solvent when a solute does not dissolve in water.
  • the flux method is a method for precipitating a single crystal by, for example, dissolving constituent elements using sodium, sodium chloride, lithium chloride or the like as a flux (flux) and controlling the temperature and pressure.
  • a DC pulse current is applied in a direction parallel to the pressing direction while a mixture of the metal oxide powder and the plate crystal of the metal oxide is uniaxially pressed to obtain a sintered body.
  • structural anisotropy is imparted to the sintered body by the TGG method (Tampled Grain Growth method).
  • TGG method stampled Grain Growth method
  • plate-like crystals with high structural anisotropy are embedded in polycrystalline particles, aligned so that the plate-like crystals are aligned by uniaxial pressing, and heat treatment is performed, whereby the powder becomes plate-like crystals.
  • An oriented sintered body can be obtained by applying a DC pulse current in a direction parallel to the pressing direction.
  • Examples of the oriented sintered body include Na x CoO 2 used in Examples.
  • the p-type semiconductor element fabricated as described above exhibits the same electrical resistivity as that of a metal and the same level of thermoelectromotive force as that of a semiconductor.
  • this p-type semiconductor element exhibits a very high thermoelectromotive force among materials exhibiting a low electrical resistivity equivalent to that of metal, and thus is preferable as a p-type semiconductor element used for a thermoelectric conversion module.
  • the common electrode and the electrode are metal materials.
  • a metal material what is used as an electrode of a general thermoelectric conversion module can be used.
  • transition metal materials such as nickel (Ni), titanium (Ti), copper (Cu), aluminum (Al), and iron (Fe) are exemplified.
  • nickel (Ni) is preferable because it has a high melting point of 1728 K and is excellent in heat resistance.
  • the common electrode and the electrode may be the same type of metal or different types of metals.
  • thermoelectric conversion module In the method for producing a thermoelectric conversion module of the present invention, a metal powder and / or a conductive metal oxide powder (in this specification, a metal powder and / or a conductive metal oxide powder is used between a semiconductor element and an electrode, etc. Sintered by applying a DC pulse current in a direction parallel to the direction in which the pressure is applied, while applying pressure in the direction in which the semiconductor element is sandwiched between electrodes. The semiconductor element is bonded to the electrode or the like. The use of the powder in this manner and the sintering of the powder together can bring about an effect of forming a tightly bonded state with the electrode.
  • the “conductivity” of the conductive metal oxide powder means that the conductivity measured by a four-terminal method is 10 3 S / cm or more using the conductive metal oxide powder as a dense sintered body.
  • the metal constituting the metal powder disposed between the semiconductor element and the electrode has a low electric resistance and is the same metal as the metal constituting the common electrode and / or the electrode, or has an ohmic contact with the semiconductor element. It is necessary to form.
  • the resistance value of the metal powder is preferably 10 ⁇ 6 ⁇ cm or less.
  • the metal constituting the metal powder include transition metal materials such as nickel, titanium (Ti), copper (Cu), aluminum (Al), and iron (Fe).
  • the metal species of the metal powder and the metal species used for the electrode or the like may be the same or different, but are preferably the same.
  • the p-type conductive metal oxide constituting the p-type conductive metal oxide powder disposed between the p-type semiconductor element and the electrode or the like forms an ohmic contact with the common electrode and the electrode.
  • it means a substance whose temperature characteristic of electrical conduction shows metallic behavior.
  • the conductive metal oxide is p-type and exhibits high electrical conductivity, and must be different from the metal oxide constituting the semiconductor.
  • the reason is that since the p-type semiconductor element and the metal cannot form an ohmic contact, the semiconductor element and the electrode are joined via a sintered body made of a conductive metal oxide exhibiting a metallic electric conduction behavior. This is because the resistance at the bonding interface can be reduced. In addition, when the junction between the semiconductor element and the metal is in ohmic contact, the resistance at the junction interface is reduced even when only the metal powder is used.
  • the p-type conductive metal oxide that can be used is not particularly limited, and is appropriately changed according to the type of p-type semiconductor, the type of metal used as a common electrode or an electrode.
  • SrRuO 3 , ReO 3 , Cu 2 O, and CuO can be mentioned.
  • the n-type conductive metal oxide constituting the n-type conductive metal oxide powder disposed between the n-type semiconductor element and the electrode forms an ohmic contact with the common electrode and the electrode.
  • it means a substance whose temperature characteristic of electrical conduction shows metallic behavior.
  • the conductive metal oxide is n-type and exhibits high electrical conductivity, and it is necessary to use a material different from the material constituting the n-type semiconductor. The reason is the same as in the case of a p-type semiconductor.
  • the n-type conductive metal oxide that can be used is not particularly limited, and is appropriately changed depending on the type of the n-type semiconductor, the type of metal used as the common electrode or the electrode.
  • the n-type semiconductor In 2 O 3 , SnO 2 , In 2 O 3 —SnO 2 , or Nb or La-doped SrTiO 3 , ZnO can be used. This is because the junction between the electrode and the n-type semiconductor element tends to be in ohmic contact.
  • the particle size of the metal powder and conductive metal oxide powder affects the density of the sintered body.
  • the particle diameter is not particularly limited as long as a sintered body dense to a desired level can be obtained, but is preferably 20 ⁇ m or less, more preferably 3 ⁇ m or less, and nanoparticles can also be used. .
  • the metal powder is preferably used as a green compact.
  • the green compact refers to a metal powder or the like that is pressed and hardened.
  • the green compact can be produced, for example, by compacting. By sandwiching the green compact between the electrode or the like and the semiconductor element, and sintering and densifying using the discharge plasma method, it becomes easy to join the electrode or the like and the semiconductor element.
  • Adhesion between a sintered body of metal powder or green compact and an electrode or the like easily proceeds because both are metal materials.
  • the adhesion between the sintered body of metal powder or the like or the green compact and the semiconductor element is presumed to proceed by the interaction of the oxide film on the particle surface of the metal powder or the like with the surface of the semiconductor element.
  • the sintered body becomes a part of the electrode.
  • a nickel (Ni) plate is used as an electrode or the like and nickel powder is used as a metal powder
  • the bulk of nickel is formed by sintering, and the sintered body is integrated with the nickel plate.
  • the sintered body of the mixed powder becomes a composite electrode of metal and conductive metal oxide, and a module as an electrode between the electrode and the semiconductor element Part of
  • thermoelectric conversion module of this invention has high productivity.
  • the p-type semiconductor element and the n-type semiconductor element are thermally expanded by heating with the discharge plasma for the above-described bonding. If the thermal expansion coefficient of the p-type semiconductor element and the thermal expansion coefficient of the n-type semiconductor element are different, it is assumed that the semiconductor element that is likely to expand is damaged. However, in the manufacturing method of the present invention, metal powder or the like or the green compact plays a role as a buffer material, and thus is caused by the difference between the thermal expansion coefficient of the p-type semiconductor element and the thermal expansion coefficient of the n-type semiconductor element. Damage to the semiconductor element can be suppressed.
  • p-type conductive metal oxide powder When a sintered body containing a metal oxide as a main component is used as the p-type semiconductor element, the junction between the electrode and the p-type semiconductor element tends not to be in ohmic contact. Therefore, p-type conductive metal oxide powder, or a mixture of metal powder and p-type conductive metal oxide powder can be used so that the junction between the electrode and the p-type semiconductor element is in ohmic contact.
  • the same effect can be obtained by using a green compact formed by compacting a p-type conductive metal oxide powder or a mixture of a metal powder and a p-type conductive metal oxide powder. The same applies to the n-type semiconductor element and the n-type conductive metal oxide.
  • the volume ratio of the metal powder to the p-type conductive metal oxide powder is preferably 3/7 to 9/1. If the volume ratio is 3/7 or more, it is preferable because the degree of sintering of the mixture is increased and the thermoelectric element and the electrode can be joined. If it is 9/1 or less, ohmic contact can be easily obtained. This is preferable. A more preferable range of the volume ratio is 5/5 to 7/3. The same applies to the metal powder and the n-type conductive metal oxide.
  • thermoelectric conversion module of the present invention can be manufactured.
  • thermoelectric conversion module of the present invention is made of a material having excellent heat resistance for both the p-type semiconductor element and the n-type semiconductor element. Therefore, the thermoelectric conversion module of the present invention can be used even in a high temperature environment of about 600 ° C. Moreover, both the p-type semiconductor element and the n-type semiconductor element used in the thermoelectric conversion module of the present invention have high performance as a thermoelectric conversion material.
  • the metal oxide used for the production of the p-type semiconductor element is preferably one selected from Na x CoO 2 , CaCo 2 O 4 , CuYO 2 , SrRuO 3 , and Sr 2 RuO 4 .
  • CuYO 2 is preferably doped with a divalent alkaline earth metal such as Ca, Mg, Sr, etc., and is preferably made into CuYO 2 + x by excess oxygen.
  • SrRuO 3 and Sr 2 RuO 4 are preferably doped with Nb.
  • the dopant contained in magnesium silicide is preferably at least one element selected from Sb and Al.
  • thermoelectric conversion module of this invention may be manufactured by methods other than the manufacturing method of the above-mentioned this invention.
  • the production by the method of the present invention is preferable from the following points.
  • conventional methods using paste and solder often do not allow these materials to withstand use at high temperatures, but use metal powders or conductive metal oxide powders. Therefore, there is almost no problem of heat resistance such as paste and solder.
  • ⁇ Manufacture of n-type semiconductor elements Magnesium silicide containing 0.5% by mass of Sb as a dopant (Union Material Co., Ltd., using Example 5 of WO2011 / 002035) is pulverized in an alumina mortar and using a 75 ⁇ m sieve made by Tokyo Screen Co., Ltd. Classification was performed to obtain a raw material powder.
  • the raw material powder was sintered using a discharge plasma sintering apparatus (Dr. Sinter LabSPS-515, manufactured by Sumitomo Coal Mining Co., Ltd.). Sintering conditions are as follows.
  • Raw material powder is filled in a graphite mold, pre-pressurization shown in Table 1 is applied, electricity is applied while performing uniaxial pressure molding, and raw material powder is shown in Table 1 at a temperature increase rate shown in Table 1.
  • the sintered body was manufactured by heating to the holding temperature and heat treatment at the holding temperature shown in Table 1 for the holding time.
  • the appearance of the sintered body of Condition 1 to the sintered body of Condition 6 was visually observed. It was confirmed that the sintered body of condition 1 was cracked, and the sintered bodies of condition 2 to condition 3 were cracked on the surface. The density of the sintered bodies of Condition 4 to Condition 6 in which no cracks were confirmed on the surface was measured. The density of the sintered body under condition 4 was 94.5%, the density of the sintered body under condition 5 was 97.2%, and the density of the sintered body under condition 6 was 99.7%. It was confirmed that the sintered body of Condition 6 was the most dense.
  • the optimum sintering condition was determined, and an n-type semiconductor element used for manufacturing the thermoelectric conversion module was obtained under this condition.
  • the preliminary pressurizing force is 50 MPa
  • the holding temperature is 800 ° C.
  • the holding time is 1 minute
  • the temperature rising rate is 0 to 600 ° C. in the range of 100 ° C./min
  • the temperature in the range of 600 to 700 ° C. is 50 ° C. / Min
  • the range of 700-800 ° C. is 30 ° C./min.
  • a sample of 5.4 mm (length) ⁇ 10.5 mm (width) ⁇ 8.5 mm (height) was cut out from the sintered body and used.
  • a part of the precursor was taken out and mixed with NaCl and KCl at a weight ratio of 2: 1: 1 (precursor: NaCl: KCl).
  • This mixture was placed in a crucible as a sample, sealed with Aron ceramics and allowed to stand for a day, and then heat treated to cure the Aron ceramics.
  • Temperature conditions temperature rise to 100 ° C in 75 minutes, hold for 2 hours, heat up to 200 ° C in 50 minutes, hold for 2 hours, heat up to 300 ° C in 20 minutes, hold for 1 hour, cool to room temperature in 60 minutes It was.
  • heat treatment for producing plate crystals was performed. As heat treatment conditions, the temperature was raised to 1100 ° C. in 100 minutes, held for 12 minutes, slowly cooled to 700 ° C.
  • a graphite mold is filled with a precursor of Na x CoO 2 sample and a plate-like crystal, a pre-pressurizing pressure of 50 MPa is applied, energized while performing uniaxial pressing, and the temperature is raised to 700 ° C. in 7 minutes. The temperature was raised to ⁇ 850 ° C. in 3 minutes and heated at this temperature for 10 minutes to produce a sintered body.
  • This sintered body was used as a p-type semiconductor element for manufacturing the following thermoelectric conversion module. Specifically, a 4.5 mm (vertical) ⁇ 9.5 mm (horizontal) ⁇ 8.5 mm (height) sample was cut out from the sintered body and used.
  • Example 1 0.5 g of nickel metal powder (2 to 3 ⁇ m, purity 99.9%) is filled into a cylindrical mold having an inner diameter of 20 mm and a height of 40 mm, and a green compact is produced under a pressure of 30 MPa. Cut out to ⁇ 5 mm ⁇ 0.5 mm. Moreover, the nickel plate was used as a common electrode and an electrode. Using the green compact, nickel plate, n-type semiconductor element, and p-type semiconductor element, the thermoelectric conversion module of Example 1 was manufactured by the following method.
  • the green compacts were respectively arranged on the upper surfaces of the two nickel plates.
  • an n-type semiconductor element is arranged so that the surface of 5.4 mm (vertical) ⁇ 10.5 mm (horizontal) is in contact with one green compact, and 4.5 mm (vertical) ⁇ on the other green compact.
  • the p-type semiconductor element was arranged so that the surface of 9.5 mm (horizontal) was in contact.
  • the green compacts were respectively disposed on the back surfaces of the surfaces where the green compacts contact the n-type and p-type semiconductor elements.
  • One nickel plate serving as a common electrode was placed on these green compacts so that the bottom surface of the nickel plate was in contact with the green compact.
  • thermoelectric conversion module was manufactured by processing.
  • thermoelectric property evaluation apparatus manufactured by ULVAC-RIKO. Specifically, a thermocouple was installed on the nickel plate, and the surface temperature on the high temperature side and the surface temperature on the low temperature side were measured. Then, a constant current was applied between the nickel plates of the thermoelectric conversion module, and the voltage drop was measured. Finally, power was calculated from the voltage drop and constant current. The measurement conditions and results are shown in Table 2 and FIG. Note that the surface temperature on the low temperature side is all 100 ° C.
  • thermoelectric conversion module of the present invention can be used in an environment of about 200 to 600 ° C. Further, the thermoelectric conversion module of the present invention has a power generation performance of 6.645 mW under a temperature difference of 500 ° C. Therefore, it was confirmed that the power generation performance is equivalent to a general thermoelectric conversion module. .
  • the SrRuO 3 powder mixed with the nickel metal powder is a p-type conductive metal having a particle size of 10 ⁇ m or less by further heat-treating the SrRuO 3 precursor powder in an atmospheric furnace at 1000 ° C. for 5 hours. An oxide powder was obtained.
  • the thermoelectric conversion module of Example 3 was manufactured.
  • the thermoelectric conversion module of Example 3 was manufactured.
  • thermoelectric conversion module of Example 1 When the power generation performance of the thermoelectric conversion module of Example 1 is compared with the power generation performance of the thermoelectric conversion modules of Examples 2 to 4, metal powder and p-type are used as powders for joining the electrode and the p-type semiconductor element. It was confirmed that the power generation performance of the thermoelectric conversion module was improved by using the mixture with the conductive metal oxide powder.
  • the magnesium silicide used in the examples has a small resistance at the bonding interface even when bonded to the metal electrode, even if n-type conductive metal oxide powder is not used, the power generation performance is not greatly reduced. .
  • the resistance of the bonding interface increases in the bonding between the n-type semiconductor element and the metal electrode, the resistance of the bonding interface can be reduced by using the n-type conductive metal oxide powder. Conceivable.
  • thermoelectric conversion modules of Examples 2 to 4 From Table 1 and Tables 2 to 4, it was confirmed that there was almost no difference in voltage drop between the thermoelectric conversion modules of Examples 2 to 4 and the thermoelectric conversion module of Example 1. On the other hand, regarding the current value, it was confirmed that the current flowing through the thermoelectric conversion modules of Examples 2 to 4 was very high compared to the current flowing through the thermoelectric conversion module of Example 1. From these results, it can be confirmed that the thermoelectric conversion modules of Examples 2 to 4 have very low resistance at the interface between the electrode and the like and the semiconductor element as compared with the thermoelectric conversion module of Example 1.
  • thermoelectric conversion module of Example 5 was manufactured in the same manner as the thermoelectric conversion module of Example 1 except that a SrRuO 3 sintered body was used as the p-type semiconductor element. Specifically, a heat-treated sintered body of SrRuO 3 was manufactured by the following method, and 4.5 mm (length) ⁇ 9.5 mm (width) ⁇ 7.5 mm (height) from the sintered body. 1) was used as a p-type semiconductor element.
  • the graphite mold is filled with the above-mentioned precursor of SrRuO 3 sample, a pre-pressurizing force of 50 MPa is applied, energized while performing uniaxial pressing, and the temperature is raised to 1100 ° C. in 11 minutes, and this temperature is increased for 4 minutes.
  • a sintered body was produced by heating. This sintered body was heat-treated in the atmosphere under the conditions of a processing temperature of 1300 ° C. and a processing time of 12 hours to obtain a SrRuO 3 sintered body.
  • thermoelectric conversion module of Example 5 was evaluated in the same manner as the power generation performance of the thermoelectric conversion module of Example 1.
  • the measurement conditions and evaluation results of Example 5 are shown in Table 6 and FIG. Note that the surface temperature on the low temperature side is all 100 ° C.
  • the power generation of the thermoelectric conversion module can be achieved by changing the type of metal oxide constituting the p-type semiconductor element. It was confirmed that the performance was greatly improved.
  • thermoelectric conversion module of Example 6 was produced in the same manner as in Example 5 except that Nb was added when producing the starting solution so that Nb in the starting solution was 5 mol%.
  • thermoelectric conversion module of Example 6 was evaluated in the same manner as the power generation performance of the thermoelectric conversion module of Example 1.
  • the measurement conditions and evaluation results of Example 6 are shown in Table 7 and FIG. Note that the surface temperature on the low temperature side is all 100 ° C.
  • thermoelectric conversion module of Example 6 When comparing the power generation performance of the thermoelectric conversion module of Example 6 with the power generation performance of the thermoelectric conversion module of Example 5, the metal oxide constituting the p-type semiconductor element is changed to a metal oxide containing a dopant. It was confirmed that the power generation performance of the thermoelectric conversion module was improved.

Abstract

Disclosed are: a method for producing a thermoelectric conversion module with high productivity; and a thermoelectric conversion module which can be used under high temperature environments and has high power-generating performance. Disclosed is a method for producing a thermoelectric conversion module comprising an n-type semiconductor element, a p-type semiconductor element, a common electrode to which one end of the n-type semiconductor element and one end of the p-type semiconductor element are connected, and an electrode to which the other end of the n-type semiconductor element and the other end of the p-type semiconductor element are connected independently, wherein a metal powder and/or an electrically conductive metal oxide powder (an n-type electrically conductive metal oxide powder or a p-type electrically conductive metal oxide powder) is arranged between the semiconductor element and the electrodes and the like, and the semiconductor element and the electrodes and the like are connected to each other in a specific manner. A sintered material containing a metal oxide as the main component is used as the p-type semiconductor element, and a sintered material containing magnesium silicide as the main component is used as the n-type semiconductor element.

Description

熱電変換モジュールの製造方法及び熱電変換モジュールThermoelectric conversion module manufacturing method and thermoelectric conversion module
　本発明は、熱電変換モジュールの製造方法及び熱電変換モジュールに関する。 The present invention relates to a method for manufacturing a thermoelectric conversion module and a thermoelectric conversion module.
　熱電変換とは、ゼーベック効果やペルチェ効果を利用して、熱エネルギーと電気エネルギーとを相互に変換することをいう。熱電変換を利用すれば、ゼーベック効果を用いて熱流から電力を取り出すことが可能である。 Thermoelectric conversion refers to the mutual conversion of thermal energy and electrical energy using the Seebeck effect or Peltier effect. If thermoelectric conversion is used, it is possible to extract electric power from the heat flow using the Seebeck effect.
　また、上記の熱電変換は、直接変換であるがためにエネルギー変換の際に余分な老廃物を排出しないこと、排熱の有効利用が可能であること等の特徴を有している。このため、熱電変換モジュールの研究は盛んに行われている。 In addition, since the above-described thermoelectric conversion is direct conversion, it has characteristics such that excess waste products are not discharged during energy conversion, and effective use of exhaust heat is possible. For this reason, research on thermoelectric conversion modules has been actively conducted.
　一般的に熱電変換モジュールは、いわゆるπ型の構造を持つ。π型の構造は、ｎ型半導体素子と、ｐ型半導体素子と（以下、ｎ型半導体素子とｐ型半導体素子とを併せて「半導体素子」という場合がある）、ｎ型半導体素子の一端とｐ型半導体素子の一端とが接合される共通電極と、ｎ型半導体素子の他端及びｐ型半導体素子の他端にそれぞれ独立して接合される電極（以下、共通電極と電極とを併せて「電極等」という場合がある。）とからなる。 Generally, thermoelectric conversion modules have a so-called π-type structure. The π-type structure includes an n-type semiconductor element, a p-type semiconductor element (hereinafter, the n-type semiconductor element and the p-type semiconductor element may be collectively referred to as “semiconductor element”), one end of the n-type semiconductor element, A common electrode to which one end of the p-type semiconductor element is joined, and an electrode to be joined independently to the other end of the n-type semiconductor element and the other end of the p-type semiconductor element (hereinafter, the common electrode and the electrode are combined) It may be referred to as “electrode etc.”).
　π型構造の熱電変換モジュールの製造において、半導体素子と電極間の接合方法としては、ペーストを用いる方法（特許文献１参照）、はんだを用いる方法（特許文献２参照）が採用される。ペーストを用いる方法、はんだを用いる方法のいずれも、π型構造の熱電変換モジュール毎に半導体素子と電極との接合を行う必要があるため、生産性の点で満足のいくものではなかった。そこで、π型構造の熱電変換モジュールの生産性を高めるために、複数のπ型構造の熱電変換モジュールを一度に製造する方法が望まれているが、そのような方法は存在しないのが現状である。 In the manufacture of a thermoelectric conversion module having a π-type structure, a method using a paste (see Patent Document 1) and a method using solder (see Patent Document 2) are employed as a bonding method between a semiconductor element and an electrode. Neither the method using paste nor the method using solder is satisfactory in terms of productivity because it is necessary to bond a semiconductor element and an electrode for each π-type thermoelectric conversion module. Therefore, in order to increase the productivity of the thermoelectric conversion module having a π-type structure, a method of manufacturing a plurality of thermoelectric conversion modules having a π-type structure at the same time is desired. However, there is currently no such method. is there.
　また、熱電変換モジュールによる発電においては、焼却炉や工業炉からの廃熱をそのまま利用することが望ましい。しかしながら、熱電変換モジュールの耐熱性が問題となり、廃熱が６００℃程度になると、発電が困難になるのが現状である。 Also, in the power generation by the thermoelectric conversion module, it is desirable to use the waste heat from the incinerator or industrial furnace as it is. However, the heat resistance of the thermoelectric conversion module becomes a problem, and when the waste heat reaches about 600 ° C., it is difficult to generate power.
　６００℃程度の高温環境下で使用可能な熱電変換モジュールの開発には、ｐ型半導体素子及びｎ型半導体素子の耐熱性の改善が必要になる。耐熱性の高い熱電変換モジュールの開発は進められているものの（特許文献３参照）、充分な耐熱性と高い発電性能を兼ね備える熱電変換モジュールは開発されていない。 Development of a thermoelectric conversion module that can be used in a high temperature environment of about 600 ° C. requires improvement of heat resistance of p-type semiconductor elements and n-type semiconductor elements. Although development of a thermoelectric conversion module with high heat resistance is underway (see Patent Document 3), no thermoelectric conversion module having sufficient heat resistance and high power generation performance has been developed.
特開２００９－１１７７９２号公報JP 2009-117772 A 特開２００９－０８８０６８号公報JP 2009-080868 A 特開２００７－１５０１１２号公報JP 2007-150112 A
　本発明は、以上の課題を解決するためになされたものであり、その目的は、熱電変換モジュールを高い生産性で製造する方法、及び高温環境下で使用可能で且つ高い発電性能を有する熱電変換モジュールを提供することにある。 The present invention has been made to solve the above-described problems, and has as its object to provide a method for manufacturing a thermoelectric conversion module with high productivity, and a thermoelectric conversion that can be used in a high temperature environment and has high power generation performance. To provide a module.
　本発明者らは、以上の課題を解決するために鋭意研究を重ねた。その結果、半導体素子と電極等との間に金属粉末及び／又は導電性金属酸化物粉末（ｎ型導電性金属酸化物粉末又はｐ型導電性金属酸化物粉末）を配置して、半導体素子と電極等とを特定の方法で接合することで、熱電変換モジュールの生産性が高まることを見出し、さらに、金属粉末と導電性金属酸化物粉末とを併用することで、熱電変換モジュールの発電性能が飛躍的に向上することも見出した。また、ｐ型半導体素子として金属酸化物を主成分とする焼結体を用い、ｎ型半導体素子としてマグネシウムシリサイドを主成分とする焼結体を用いれば、熱電変換モジュールは、高温環境下で使用可能であることを見出し、さらに、熱電変換モジュールを構成する材料の選択により、熱電変換モジュールの発電性能が飛躍的に向上することも見出した。本発明はこのような知見に基づいてなされたものであり、具体的には以下の通りである。 The present inventors have intensively studied to solve the above problems. As a result, a metal powder and / or conductive metal oxide powder (n-type conductive metal oxide powder or p-type conductive metal oxide powder) is disposed between the semiconductor element and the electrode, etc. It is found that the productivity of the thermoelectric conversion module is increased by joining the electrodes and the like by a specific method, and further, the power generation performance of the thermoelectric conversion module is improved by using the metal powder and the conductive metal oxide powder in combination. I also found a dramatic improvement. In addition, if a sintered body mainly composed of metal oxide is used as a p-type semiconductor element and a sintered body mainly composed of magnesium silicide is used as an n-type semiconductor element, the thermoelectric conversion module can be used in a high temperature environment. It has also been found that this is possible, and further, it has also been found that the power generation performance of the thermoelectric conversion module is drastically improved by selecting the material constituting the thermoelectric conversion module. The present invention has been made on the basis of such findings, and is specifically as follows.
　（１）　ｎ型半導体素子と、ｐ型半導体素子と、前記ｎ型半導体素子の一端と前記ｐ型半導体素子の一端とが接合される共通電極と、前記ｎ型半導体素子の他端及び前記ｐ型半導体素子の他端にそれぞれ独立して接合される電極と、を備える熱電変換モジュールの製造方法であって、前記ｎ型半導体素子と、前記共通電極及び電極との間に金属粉末及び／又はｎ型導電性金属酸化物粉末を配置し、前記ｐ型半導体素子と、前記共通電極及び電極との間に金属粉末及び／又はｐ型導電性金属酸化物粉末を配置し、前記ｎ型半導体素子及びｐ型半導体素子を前記共通電極及び前記電極で挟む方向に圧力を印加しながら、前記圧力が印加される方向と平行な方向に直流パルス電流を印加して焼結し、前記ｎ型半導体素子と前記共通電極及び電極との間及び前記ｐ型半導体素子と前記共通電極及び電極との間を接合する熱電変換モジュールの製造方法。 (1) An n-type semiconductor element, a p-type semiconductor element, a common electrode where one end of the n-type semiconductor element and one end of the p-type semiconductor element are joined, the other end of the n-type semiconductor element, and the p A thermoelectric conversion module comprising: an electrode that is independently joined to the other end of the type semiconductor element; and a metal powder and / or between the n type semiconductor element and the common electrode and the electrode An n-type conductive metal oxide powder is disposed, a metal powder and / or a p-type conductive metal oxide powder is disposed between the p-type semiconductor element and the common electrode, and the n-type semiconductor element. And applying a DC pulse current in a direction parallel to the direction in which the pressure is applied while applying pressure in a direction in which the p-type semiconductor element is sandwiched between the common electrode and the electrode, and sintering the n-type semiconductor element And the common electrode and the electrode During and method of manufacturing the thermoelectric conversion module of joining between the common electrode and the electrode and the p-type semiconductor element.
　（２）　前記金属粉末及び／又はｎ型導電性金属酸化物粉末、並びに前記金属粉末及び／又はｐ型導電性金属酸化物粉末は、圧粉体である（１）に記載の熱電変換モジュールの製造方法。 (2) The metal powder and / or the n-type conductive metal oxide powder and the metal powder and / or the p-type conductive metal oxide powder are green compacts of the thermoelectric conversion module according to (1). Production method.
　（３）　前記ｎ型半導体素子と前記共通電極及び電極との間に、金属粉末とｎ型導電性金属酸化物粉末との混合物を配置し、前記ｐ型半導体素子と前記共通電極及び電極との間に、金属粉末とｐ型導電性金属酸化物粉末との混合物を配置する（１）又は（２）に記載の熱電変換モジュールの製造方法。 (3) A mixture of metal powder and n-type conductive metal oxide powder is disposed between the n-type semiconductor element and the common electrode and electrode, and the p-type semiconductor element and the common electrode and electrode are The manufacturing method of the thermoelectric conversion module as described in (1) or (2) which arrange | positions the mixture of metal powder and p-type electroconductive metal oxide powder in between.
　（４）　前記ｐ型半導体素子は、前記共通電極及び前記電極との接合に用いられる前記ｐ型導電性金属酸化物と異なる金属酸化物を主成分とする焼結体であり、前記ｎ型半導体素子は、Ｓｂ、Ａｌから選択される少なくとも一種の元素をドーパントとして含むマグネシウムシリサイドを主成分とする焼結体又はマグネシウムシリサイドを主成分とする焼結体である（１）乃至（３）のいずれか１に記載の熱電変換モジュールの製造方法。 (4) The p-type semiconductor element is a sintered body mainly composed of a metal oxide different from the p-type conductive metal oxide used for joining the common electrode and the electrode, and the n-type semiconductor The element is any one of (1) to (3) which is a sintered body containing magnesium silicide as a main component or containing magnesium silicide as a main component and containing at least one element selected from Sb and Al as a dopant. A method for producing the thermoelectric conversion module according to claim 1.
　（５）　前記ｐ型半導体素子は、前記金属酸化物の粉体と前記金属酸化物の板状結晶との混合物を、一軸加圧成形しながら加圧方向と平行に直流パルス電流を印加して、焼結させた焼結体である（４）に記載の熱電変換モジュールの製造方法。 (5) The p-type semiconductor element applies a DC pulse current parallel to the pressing direction while uniaxially pressing a mixture of the metal oxide powder and the metal oxide plate crystal. The method for producing a thermoelectric conversion module according to (4), wherein the sintered body is sintered.
　（６）　ｎ型半導体素子と、ｐ型半導体素子と、前記ｎ型半導体素子の一端と前記ｐ型半導体素子の一端とが接合される共通電極と、前記ｎ型半導体素子の他端及び前記ｐ型半導体素子の他端にそれぞれ独立して接合される電極と、を備え、前記ｐ型半導体素子の端部と前記共通電極及び電極との接合部が、金属の焼結体、金属とｐ型導電性金属酸化物の混合物の焼結体又はｐ型導電性金属酸化物の焼結体から構成され、前記ｎ型半導体素子の端部と前記共通電極及び電極との接合部が、金属の焼結体、金属とｎ型導電性金属酸化物の混合物の焼結体又はｎ型導電性金属酸化物の焼結体から構成される熱電変換モジュール。 (6) an n-type semiconductor element, a p-type semiconductor element, a common electrode at which one end of the n-type semiconductor element and one end of the p-type semiconductor element are joined, the other end of the n-type semiconductor element, and the p An electrode that is independently joined to the other end of the p-type semiconductor element, and the junction between the end of the p-type semiconductor element and the common electrode and the electrode is a sintered metal, a metal and p-type It is composed of a sintered body of a mixture of conductive metal oxides or a sintered body of p-type conductive metal oxides, and the joint between the end of the n-type semiconductor element and the common electrode and the electrode is made of a sintered metal. A thermoelectric conversion module comprising a bonded body, a sintered body of a mixture of a metal and an n-type conductive metal oxide, or a sintered body of an n-type conductive metal oxide.
　（７）　前記ｐ型半導体素子の端部と前記共通電極及び電極との接合部が、金属とｐ型導電性金属酸化物の混合物の焼結体から構成され、前記ｎ型半導体素子の端部と前記共通電極及び電極との接合部が、金属とｎ型導電性金属酸化物の混合物の焼結体から構成される（６）に記載の熱電変換モジュール。 (7) The junction between the end of the p-type semiconductor element and the common electrode and the electrode is composed of a sintered body of a mixture of a metal and a p-type conductive metal oxide, and the end of the n-type semiconductor element The thermoelectric conversion module according to (6), wherein a joint between the common electrode and the electrode is formed of a sintered body of a mixture of a metal and an n-type conductive metal oxide.
　（８）　前記ｐ型半導体素子は、前記接合部を構成するｐ型導電性金属酸化物と異なる金属酸化物を主成分とする焼結体であり、前記ｎ型半導体素子は、マグネシウムシリサイドを主成分とする焼結体である（６）又は（７）に記載の熱電変換モジュール。 (8) The p-type semiconductor element is a sintered body whose main component is a metal oxide different from the p-type conductive metal oxide constituting the junction, and the n-type semiconductor element is mainly made of magnesium silicide. The thermoelectric conversion module according to (6) or (7), which is a sintered body as a component.
　（９）　前記マグネシウムシリサイドを主成分とする焼結体が、ドーパントを含むものである（８）に記載の熱電変換モジュール。 (9) The thermoelectric conversion module according to (8), wherein the sintered body containing magnesium silicide as a main component includes a dopant.
　（１０）　前記ドーパントは、Ｓｂ、Ａｌから選択される少なくとも一種の元素である（９）に記載の熱電変換モジュール。 (10) The thermoelectric conversion module according to (9), wherein the dopant is at least one element selected from Sb and Al.
　（１１）　前記ｐ型半導体素子を構成する前記金属酸化物が、ＮａｘＣｏＯ２、ＣａＣｏ２Ｏ４、ＣｕＹＯ２、ＳｒＲｕＯ３、及びＳｒ２ＲｕＯ４から選択される（８）乃至（１０）のいずれか１に記載の熱電変換モジュール。 (11) The metal oxide constituting the p-type semiconductor element is selected from Na x CoO 2 , CaCo 2 O 4 , CuYO 2 , SrRuO 3 , and Sr 2 RuO 4 (8) to (10) The thermoelectric conversion module of any one.
　（１２）　前記接合部の焼結体を構成するｐ型導電性金属酸化物がＳｒＲｕＯ３、ＲｅＯ３、Ｃｕ２Ｏ及びＣｕＯから選択される（６）乃至（１１）のいずれか１に記載の熱電変換モジュール。 (12) The p-type conductive metal oxide constituting the sintered body of the joint is selected from SrRuO 3 , ReO 3 , Cu 2 O and CuO, according to any one of (6) to (11) Thermoelectric conversion module.
　（１３）　前記接合部の焼結体を構成するｎ型導電性金属酸化物がＩｎ２Ｏ３、ＳｎＯ２、Ｉｎ２Ｏ３－ＳｎＯ２、もしくはＮｂ又はＬａドープＳｒＴｉＯ３、ＺｎＯである（６）乃至（１２）のいずれか１に記載の熱電変換モジュール。 (13) The n-type conductive metal oxide constituting the sintered body of the joint is In 2 O 3 , SnO 2 , In 2 O 3 —SnO 2 , or Nb or La-doped SrTiO 3 , ZnO (6 The thermoelectric conversion module according to any one of (12) to (12).
　本発明の熱電変換モジュールの製造方法によれば、一度に複数のπ型構造の熱電変換モジュールを製造することができる。このため、先述の従来のπ型構造の熱電変換モジュールの製造方法と比較して、本発明の熱電変換モジュールの製造方法は、高い生産性を有する。 According to the method for manufacturing a thermoelectric conversion module of the present invention, a plurality of π-type thermoelectric conversion modules can be manufactured at a time. For this reason, compared with the manufacturing method of the conventional thermoelectric conversion module of the above-mentioned pi type structure, the manufacturing method of the thermoelectric conversion module of the present invention has high productivity.
　特に、本発明の製造方法において、電極及び共通電極と半導体素子との接合に金属粉末及び／又は導電性金属酸化物を用いると、高い発電性能を有する熱電変換モジュールが得られ、特に金属粉末と導電性金属酸化物を併用すると、その性能は飛躍的に向上する。 In particular, in the manufacturing method of the present invention, when metal powder and / or conductive metal oxide is used for joining the electrode and common electrode to the semiconductor element, a thermoelectric conversion module having high power generation performance is obtained. When a conductive metal oxide is used in combination, the performance is dramatically improved.
　本発明の熱電変換モジュールは、使用されるｐ型半導体素子及びｎ型半導体素子として耐熱性が高いものを用いることが好ましく、したがって、得られる熱電変換モジュールは、高温環境下で使用可能である。 The thermoelectric conversion module of the present invention preferably uses a p-type semiconductor element and an n-type semiconductor element that have high heat resistance, and thus the obtained thermoelectric conversion module can be used in a high temperature environment.
　特に、本発明の熱電変換モジュールのｐ型半導体素子として、特定の金属酸化物を使用すると、熱電返還モジュールの発電性能が非常に高まる。 In particular, when a specific metal oxide is used as the p-type semiconductor element of the thermoelectric conversion module of the present invention, the power generation performance of the thermoelectric return module is greatly enhanced.
本発明の方法で製造される熱電変換モジュールを模式的に示す図である。It is a figure which shows typically the thermoelectric conversion module manufactured with the method of this invention. 実施例１の熱電変換モジュールの発電性能の評価結果を示す図である。It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 1. FIG. 実施例２の熱電変換モジュールの発電性能の評価結果を示す図である。It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 2. FIG. 実施例３の熱電変換モジュールの発電性能の評価結果を示す図である。It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 3. FIG. 実施例４の熱電変換モジュールの発電性能の評価結果を示す図である。It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 4. 実施例５の熱電変換モジュールの発電性能の評価結果を示す図である。It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 5. FIG. 実施例６の熱電変換モジュールの発電性能の評価結果を示す図である。It is a figure which shows the evaluation result of the electric power generation performance of the thermoelectric conversion module of Example 6.
　以下、本発明の実施形態について説明するが、本発明は以下の実施形態に限定されない。 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.
　図１は、本発明の熱電変換モジュールの概略図であり、ｎ型半導体素子１０と、ｐ型半導体素子１１と、ｎ型半導体素子の一端とｐ型半導体素子の一端とが接合される共通電極１２と、ｎ型半導体素子の他端及びｐ型半導体素子の他端にそれぞれ独立して接合される電極１３と、を備える。以下、熱電変換モジュールの各部品について、ｎ型半導体素子、ｐ型半導体素子、共通電極及び電極の順で説明した後、本発明の製造方法について説明する。 FIG. 1 is a schematic diagram of a thermoelectric conversion module according to the present invention, in which an n-type semiconductor element 10, a p-type semiconductor element 11, a common electrode at which one end of an n-type semiconductor element and one end of a p-type semiconductor element are joined. 12 and an electrode 13 that is independently joined to the other end of the n-type semiconductor element and the other end of the p-type semiconductor element. Hereinafter, after describing each part of the thermoelectric conversion module in the order of the n-type semiconductor element, the p-type semiconductor element, the common electrode, and the electrode, the manufacturing method of the present invention will be described.
＜ｎ型半導体素子＞
　本発明の熱電変換モジュールを構成するｎ型半導体素子としては特に限定されず、熱電変換モジュールに用いられる従来公知のｎ型半導体素子を使用することができる。 <N-type semiconductor element>
It does not specifically limit as an n-type semiconductor element which comprises the thermoelectric conversion module of this invention, The conventionally well-known n-type semiconductor element used for a thermoelectric conversion module can be used.
　従来公知のｎ型半導体素子の中でも、対環境性、経済性等の面で、マグネシウムシリサイド（Ｍｇ２Ｓｉ）を用いるのが好ましく、さらに本発明者等が提案し、ＷＯ２００８／０７５７８９Ａ１、ＷＯ２０１１／００２０３５Ａ１及びＷＯ２０１１／０１３６０９Ａ１の国際公開公報に示されるものを用いることが特に好ましい。 Among the conventionally known n-type semiconductor elements, it is preferable to use magnesium silicide (Mg 2 Si) in terms of environmental friendliness, economy, and the like. It is particularly preferable to use those disclosed in WO2011 / 013609A1.
　上記国際番号ＷＯ２０１１／００２０３５Ａ１に示されるマグネシウムシリサイドは、融点が１３５８Ｋ、線膨張係数が１５．５×１０－６／Ｋ（２９３℃）であり、熱的に安定で熱電変換効率も高い。加えて、マグネシウムシリサイドはヤング率が約１２０ＧＰａであり、優れた剛性も有する。 Magnesium silicide shown in the international number WO2011 / 002035A1 has a melting point of 1358K, a linear expansion coefficient of 15.5 × 10 −6 / K (293 ° C.), is thermally stable, and has high thermoelectric conversion efficiency. In addition, magnesium silicide has a Young's modulus of about 120 GPa and has excellent rigidity.
　マグネシウムシリサイドには、必要に応じて選択されるドーパントを含めることができる。マグネシウムシリサイドに含まれるドーパントとしては、特に限定されないが、例えば、Ｓｂ、Ａｌ等が用いると、電気抵抗率を低下させ、あるいは耐久性を高めるのに有効である。また、該ドーパントの含有量は特に限定されないが、０．１～１質量％であることが好ましい。なお、ドーパントとしてＳｂを含むマグネシウムシリサイドをｎ型半導体素子として使用することが特に好ましい。 Magnesium silicide can contain a dopant selected as necessary. Although it does not specifically limit as a dopant contained in magnesium silicide, For example, when Sb, Al, etc. are used, it is effective in reducing an electrical resistivity or improving durability. The content of the dopant is not particularly limited, but is preferably 0.1 to 1% by mass. It is particularly preferable to use magnesium silicide containing Sb as a dopant as the n-type semiconductor element.
　マグネシウムシリサイドの製造法は、特に限定されないが、例えば、本発明者等が提案した先述の国際公開公報に記載される方法が好ましく、次のような手順で行うことができる。先ず、マグネシウム（Ｍｇ）とシリコン（Ｓｉ）を原料として、両者を混合後、溶融し反応させてマグネシウムシリサイドを合成し、それを粉砕して粉末にし、次いでこの粉末を焼結させて、ｎ型熱電変換素子として有用な所期のマグネシウムシリサイドを得ることができる。 The method for producing magnesium silicide is not particularly limited, but, for example, the method described in the above-mentioned international publication proposed by the present inventors is preferable, and can be performed by the following procedure. First, using magnesium (Mg) and silicon (Si) as raw materials, both are mixed, melted and reacted to synthesize magnesium silicide, pulverized into powder, and then this powder is sintered to form n-type A desired magnesium silicide useful as a thermoelectric conversion element can be obtained.
　マグネシウムシリサイドの粉末の製造において、マグネシウムとシリコンを原料として、マグネシウムシリサイドの合成を実施する際には、合成温度をマグネシウムシリサイドの融点（１３５８Ｋ）より高い温度（例えば１３７０～１４００Ｋ）で実施し、系全体を融液とした状態で合成する方法が好ましい。均一なマグネシウムシリサイドを得ることができるからである。得られたマグネシウムシリサイドを粉砕し、マグネシウムシリサイドの粉末にする。なお、マグネシウムシリサイドの粉末の平均粒子径は、特に制限はないが、例えば２５～１００μｍに調整することが好ましい。 In the production of magnesium silicide powder, when magnesium silicide is synthesized using magnesium and silicon as raw materials, the synthesis temperature is higher than the melting point of magnesium silicide (1358 K) (for example, 1370 to 1400 K). A method of synthesizing the whole as a melt is preferred. This is because uniform magnesium silicide can be obtained. The obtained magnesium silicide is pulverized to form magnesium silicide powder. The average particle diameter of the magnesium silicide powder is not particularly limited, but is preferably adjusted to, for example, 25 to 100 μm.
　マグネシウムシリサイドの粉末を焼結する方法としては、ホットプレス焼結法、熱間等方圧加圧焼結法、放電プラズマ焼結法等の従来公知の方法を採用することができる。従来公知の焼結方法の中でも、放電プラズマ焼結法の採用が最も好ましい。短時間で緻密な焼結体を得ることができるからである。 As a method for sintering the magnesium silicide powder, a conventionally known method such as a hot press sintering method, a hot isostatic pressing method, or a discharge plasma sintering method can be employed. Among the conventionally known sintering methods, it is most preferable to employ a discharge plasma sintering method. This is because a dense sintered body can be obtained in a short time.
　放電プラズマ焼結は、マグネシウムシリサイドの粉末を一軸加圧成形しながら、加圧方向と平行な方向に直流パルス電流を印加して、焼結体を得る方法である。放電プラズマ焼結は、具体的には従来公知の装置を用いて、以下の方法で行うことができる。先ず、試料を充填した型をチャンバー内の焼結ステージ上にセットしてグラファイト電極で挟み、加圧しながらパルス通電を行う。次いで、試料の温度を数分以内に室温より一気に７００～２５００℃へ急速昇温する。最後に、昇温後の温度で数分間試料を保持して焼結体を得る。 Discharge plasma sintering is a method of obtaining a sintered body by applying a DC pulse current in a direction parallel to the pressing direction while uniaxially pressing magnesium silicide powder. Specifically, spark plasma sintering can be performed by the following method using a conventionally known apparatus. First, a mold filled with a sample is set on a sintering stage in a chamber, sandwiched between graphite electrodes, and pulsed while conducting pressure. Next, the temperature of the sample is rapidly raised from room temperature to 700 to 2500 ° C. within a few minutes. Finally, the sample is held for several minutes at the temperature after the temperature rise to obtain a sintered body.
　焼結条件の中でも、昇温速度がマグネシウムシリサイドの品質に特に影響を与える。６００℃以下を昇温速度８０～１２０℃／分、６００～７００℃までを昇温速度４０～６０℃／分、７００℃以上を昇温速度２０～４０℃／分に設定することが好ましい。なお、他の条件は、圧力を２０～７０ＭＰａ、昇温後の温度を７００～９００℃、保持時間を３０秒～１５分に設定することが好ましい。 Among the sintering conditions, the rate of temperature rise affects the quality of magnesium silicide. It is preferable to set 600 ° C. or less at a temperature increase rate of 80 to 120 ° C./min, 600 to 700 ° C. at a temperature increase rate of 40 to 60 ° C./min, and 700 ° C. or more at a temperature increase rate of 20 to 40 ° C./min. The other conditions are preferably set such that the pressure is 20 to 70 MPa, the temperature after the temperature rise is 700 to 900 ° C., and the holding time is 30 seconds to 15 minutes.
＜ｐ型半導体素子＞
　本発明の熱電変換モジュールを構成するｐ型半導体素子は特に限定されず、熱電変換モジュールに用いられる従来公知のｐ型半導体を使用することができる。特に、ｐ型半導体素子として金属酸化物を主成分とする焼結体の使用が好ましい。ここで、「主成分」とは、本発明の効果を害さない範囲で他の成分がｐ型半導体素子に含まれていてもよいことを指す。 <P-type semiconductor element>
The p-type semiconductor element which comprises the thermoelectric conversion module of this invention is not specifically limited, The conventionally well-known p-type semiconductor used for a thermoelectric conversion module can be used. In particular, it is preferable to use a sintered body containing a metal oxide as a main component as a p-type semiconductor element. Here, the “main component” means that other components may be contained in the p-type semiconductor element as long as the effects of the present invention are not impaired.
　金属酸化物としては、ＮａｘＣｏＯ２、ＣａＣｏ２Ｏ４、ＣｕＹＯ２、ＳｒＲｕＯ３、及びＳｒ２ＲｕＯ４等を例示することができる。また、例えば、ＣｕＹＯ２ではＣａ、Ｍｇ、Ｓｒ等の２価のアルカリ土類金属をドープしてもよく、酸素を過剰にしてＣｕＹＯ２＋ｘにしてもよい。また、ＳｒＲｕＯ３及びＳｒ２ＲｕＯ４では、Ｎｂをドープしてもよい。これらの中でも、特に、ＳｒＲｕＯ３を主成分とするｐ型半導体素子が好ましい。電極等とｐ型半導体素子との接合がオーミック接触になりやすい傾向にあるからである。 Examples of the metal oxide include Na x CoO 2 , CaCo 2 O 4 , CuYO 2 , SrRuO 3 , and Sr 2 RuO 4 . In addition, for example, CuYO 2 may be doped with a divalent alkaline earth metal such as Ca, Mg, Sr, etc., or oxygen may be excessive to form CuYO 2 + x . In SrRuO 3 and Sr 2 RuO 4 , Nb may be doped. Among these, a p-type semiconductor element mainly containing SrRuO 3 is preferable. This is because the junction between the electrode and the p-type semiconductor element tends to be in ohmic contact.
　また、金属酸化物は、耐熱性に優れるため、高温環境下で使用される熱電変換モジュールに用いるｐ型半導体素子として好ましい。 Moreover, since metal oxide is excellent in heat resistance, it is preferable as a p-type semiconductor element used in a thermoelectric conversion module used in a high temperature environment.
　金属酸化物の焼結体の製造は、次の手順で行うことができる。先ず、金属の有機化合物や無機化合物を原料として、金属酸化物の粉末を作製する。次いで、この粉末を焼結させる。 The metal oxide sintered body can be manufactured by the following procedure. First, metal oxide powder is prepared using a metal organic compound or an inorganic compound as a raw material. The powder is then sintered.
　金属酸化物の粉末の作製は、ゾル・ゲル法、金属－有機錯体の熱分解法や共沈法等の金属元素を含む溶液を出発とする従来公知の方法を用いて行うことができる。ゾル・ゲル法とは、一般に、金属の有機化合物や無機化合物等の出発原料を溶媒に溶かして溶液として、溶液中で加水分解や縮重合等の化学反応を起こし、溶液を金属酸化物又は水酸化物の微粒子が溶解したゾル溶液にする方法である。かかるゾル溶液の反応をさらに進行させると、ゾル溶液が凝集したゲル化物が形成される。かかるゲル化物を熱処理して内部に残された溶媒を取り除くと、金属酸化物の微粒子の凝集物が得られる。この凝集物を粉砕して金属酸化物の粉体を得る。 The metal oxide powder can be prepared by a conventionally known method starting from a solution containing a metal element, such as a sol-gel method, a thermal decomposition method of a metal-organic complex, or a coprecipitation method. In general, the sol-gel method is a solution in which a starting material such as a metal organic compound or inorganic compound is dissolved in a solvent to cause a chemical reaction such as hydrolysis or polycondensation in the solution. This is a method of forming a sol solution in which oxide fine particles are dissolved. When the reaction of the sol solution is further advanced, a gelled product in which the sol solution is aggregated is formed. When the gelled product is heat-treated to remove the solvent remaining inside, an aggregate of metal oxide fine particles is obtained. The aggregate is pulverized to obtain a metal oxide powder.
　金属酸化物の粉末を焼結させる方法は特に限定されないが、例えば、ホットプレス焼結法、熱間等方圧加圧焼結法、放電プラズマ焼結法等を例示することができる。これらの焼結方法の中でも、放電プラズマ焼結法の採用が最も好ましい。短時間で緻密な焼結体を得ることができるからである。 The method for sintering the metal oxide powder is not particularly limited, and examples thereof include a hot press sintering method, a hot isostatic pressing method, and a discharge plasma sintering method. Among these sintering methods, it is most preferable to employ a discharge plasma sintering method. This is because a dense sintered body can be obtained in a short time.
　ところで、金属酸化物の結晶の中には、電気抵抗率に異方性のあるものが存在する。金属酸化物の結晶において、電気抵抗率の異方性が存在する場合、熱電変換モジュール中で電気が流れる方向と電気抵抗率が低くなる方向とを揃えることが好ましい。電気が流れる方向と電気抵抗率が低くなる方向とを揃えるためには、例えば、以下の方法で金属酸化物の焼結体を製造する。 Incidentally, some metal oxide crystals are anisotropic in electrical resistivity. When there is anisotropy in electrical resistivity in the metal oxide crystal, it is preferable to align the direction in which electricity flows in the thermoelectric conversion module with the direction in which the electrical resistivity decreases. In order to align the direction in which electricity flows and the direction in which the electrical resistivity decreases, for example, a metal oxide sintered body is manufactured by the following method.
　先ず、ゾル・ゲル法や共沈法等の従来公知の方法を用いて、金属酸化物の粉体を作製する。
　次いで、例えばフラックス法を用いて金属酸化物の粉体から板状結晶を作製する。ここで、フラックスとは、溶媒のことであり、溶質が水に溶けない場合等に溶媒とする物質の総称をいう。フラックス法とは、例えばナトリウム、塩化ナトリウム、塩化リチウム等を融剤（フラックス）として用いて構成元素を溶解させ、温度圧力を制御することによって、単結晶を析出させる方法である。
　最後に、金属酸化物の粉体と上記金属酸化物の板状結晶との混合物を一軸加圧成形しながら、加圧方向と平行な方向に直流パルス電流を印加して焼結体を得る。ここでは、真空プラズマ焼結中に、ＴＧＧ法（Ｔａｍｐｌａｔｅｄ　Ｇｒａｉｎ　Ｇｒｏｗｔｈ法）によって、焼結体に構造異方性が付与される。ＴＧＧ法とは、多結晶粒子に構造異方性の高い板状結晶を埋入し、一軸加圧により板状結晶が並ぶように向きを揃え、熱処理を加えることにより、粉体が板状結晶よりａ－ｃ面方向に影響を受けて成長し、構造異方性を金属酸化物に持たせる方法をいう。なお、この方法は、真空プラズマ焼結法と同時に行うことが可能である。 First, a metal oxide powder is prepared using a conventionally known method such as a sol-gel method or a coprecipitation method.
Next, a plate-like crystal is produced from the metal oxide powder using, for example, a flux method. Here, the flux refers to a solvent, and is a generic name for substances used as a solvent when a solute does not dissolve in water. The flux method is a method for precipitating a single crystal by, for example, dissolving constituent elements using sodium, sodium chloride, lithium chloride or the like as a flux (flux) and controlling the temperature and pressure.
Finally, a DC pulse current is applied in a direction parallel to the pressing direction while a mixture of the metal oxide powder and the plate crystal of the metal oxide is uniaxially pressed to obtain a sintered body. Here, during vacuum plasma sintering, structural anisotropy is imparted to the sintered body by the TGG method (Tampled Grain Growth method). In the TGG method, plate-like crystals with high structural anisotropy are embedded in polycrystalline particles, aligned so that the plate-like crystals are aligned by uniaxial pressing, and heat treatment is performed, whereby the powder becomes plate-like crystals. It refers to a method in which a metal oxide has structural anisotropy by growing under the influence of the ac plane direction. This method can be performed simultaneously with the vacuum plasma sintering method.
　また、ゾル・ゲル法や共沈法等の金属元素を含む溶液を出発とする従来公知の方法で板状結晶が得られる場合には、得られた板状結晶のみを一軸加圧成形しながら、加圧方向と平行な方向に直流パルス電流を印加することで配向性焼結体を得ることができる。配向性焼結体としては、実施例で使用されるＮａｘＣｏＯ２等を例示することができる。 When plate crystals are obtained by a conventionally known method starting with a solution containing a metal element such as a sol-gel method or a coprecipitation method, only the obtained plate crystals are uniaxially pressed. An oriented sintered body can be obtained by applying a DC pulse current in a direction parallel to the pressing direction. Examples of the oriented sintered body include Na x CoO 2 used in Examples.
　上記のようにして作製したｐ型半導体素子は、金属と同程度の電気抵抗率を示し、半導体と同程度の熱起電力を示す。つまり、このｐ型半導体素子は、金属と同程度の低い電気抵抗率を示す材料の中で、非常に高い熱起電力を示すため、熱電変換モジュールに使用するｐ型半導体素子として好ましい。 The p-type semiconductor element fabricated as described above exhibits the same electrical resistivity as that of a metal and the same level of thermoelectromotive force as that of a semiconductor. In other words, this p-type semiconductor element exhibits a very high thermoelectromotive force among materials exhibiting a low electrical resistivity equivalent to that of metal, and thus is preferable as a p-type semiconductor element used for a thermoelectric conversion module.
＜共通電極及び電極＞
　共通電極及び電極は、金属材料である。金属材料としては、一般的な熱電変換モジュールの電極として使用されるものを使用できる。具体的には、ニッケル（Ｎｉ）、チタン（Ｔｉ）、銅（Ｃｕ）、アルミニウム（Ａｌ）、鉄（Ｆｅ）等の遷移金属系材料が例示される。これらの中でも、ニッケル（Ｎｉ）は、融点が１７２８Ｋと高いため、耐熱性にも優れるので好ましい。共通電極と電極とは同じ種類の金属であっても、異なる種類の金属であってもよい。 <Common electrode and electrode>
The common electrode and the electrode are metal materials. As a metal material, what is used as an electrode of a general thermoelectric conversion module can be used. Specifically, transition metal materials such as nickel (Ni), titanium (Ti), copper (Cu), aluminum (Al), and iron (Fe) are exemplified. Among these, nickel (Ni) is preferable because it has a high melting point of 1728 K and is excellent in heat resistance. The common electrode and the electrode may be the same type of metal or different types of metals.
＜熱電変換モジュールの製造方法＞
　本発明の熱電変換モジュールの製造方法では、半導体素子と電極等との間に金属粉末及び／又は導電性金属酸化物粉末（本明細書において、金属粉末及び／又は導電性金属酸化物粉末を「金属粉末等」という場合がある。）を配置し、半導体素子を電極等で挟む方向に圧力を印加しながら、圧力が印加される方向と平行な方向に直流パルス電流を印加して焼結し、半導体素子と電極等との間を接合する。こうして粉末を用いることと、さらにそれを焼結することを合わせて、電極と密な接合状態を形成する効果をもたらすことができる。 <Method for manufacturing thermoelectric conversion module>
In the method for producing a thermoelectric conversion module of the present invention, a metal powder and / or a conductive metal oxide powder (in this specification, a metal powder and / or a conductive metal oxide powder is used between a semiconductor element and an electrode, etc. Sintered by applying a DC pulse current in a direction parallel to the direction in which the pressure is applied, while applying pressure in the direction in which the semiconductor element is sandwiched between electrodes. The semiconductor element is bonded to the electrode or the like. The use of the powder in this manner and the sintering of the powder together can bring about an effect of forming a tightly bonded state with the electrode.
　また、半導体素子と電極等との接合に金属及び／又は導電性金属酸化物を用いるのは、ｎ型並びにｐ型半導体素子は多くの金属と直接オーミック接触を得ることができないためである。ここで導電性金属酸化物粉末の「導電性」とは、導電性金属酸化物粉末を緻密な焼結体とし、４端子法で測定した電導度が１０３Ｓ／ｃｍ以上のことを指す。 The reason why metals and / or conductive metal oxides are used for the junction between the semiconductor element and the electrode is that n-type and p-type semiconductor elements cannot obtain direct ohmic contact with many metals. Here, the “conductivity” of the conductive metal oxide powder means that the conductivity measured by a four-terminal method is 10 3 S / cm or more using the conductive metal oxide powder as a dense sintered body.
　さらに、粉末を用いることに加えて焼結するのは、電極と密な接触状態を形成するためである。 Furthermore, the reason why sintering is performed in addition to the use of powder is to form a close contact state with the electrode.
　半導体素子と電極等との間に配置される金属粉末を構成する金属は、電気抵抗が低く、上記共通電極及び／又は電極を構成する金属と同一の金属か、又は上記半導体素子とオーミック接触を形成するものであることが必要である。ここで、金属粉末の抵抗値は、１０－６Ωｃｍ以下であることが好ましい。上記金属粉末を構成する金属としては、例えば、ニッケル、チタン（Ｔｉ）、銅（Ｃｕ）、アルミニウム（Ａｌ）、鉄（Ｆｅ）等の遷移金属系材料が例示される。金属粉末の金属種と電極等に用いられる金属種とは、同じであっても、異なっていてもよいが、同じであることが好ましい。 The metal constituting the metal powder disposed between the semiconductor element and the electrode has a low electric resistance and is the same metal as the metal constituting the common electrode and / or the electrode, or has an ohmic contact with the semiconductor element. It is necessary to form. Here, the resistance value of the metal powder is preferably 10 −6 Ωcm or less. Examples of the metal constituting the metal powder include transition metal materials such as nickel, titanium (Ti), copper (Cu), aluminum (Al), and iron (Fe). The metal species of the metal powder and the metal species used for the electrode or the like may be the same or different, but are preferably the same.
　また、ｐ型半導体素子と電極等との間に配置されるｐ型導電性金属酸化物粉末を構成するｐ型導電性金属酸化物とは、共通電極及び電極とオーミック接触を形成するものであり、電気伝導の温度特性が金属的挙動を示す物質を意味する。該導電性金属酸化物としては、ｐ型で高い電気伝導を示すものであることを特徴とし、上記半導体を構成する金属酸化物とは異なるものを用いる必要がある。 The p-type conductive metal oxide constituting the p-type conductive metal oxide powder disposed between the p-type semiconductor element and the electrode or the like forms an ohmic contact with the common electrode and the electrode. In other words, it means a substance whose temperature characteristic of electrical conduction shows metallic behavior. The conductive metal oxide is p-type and exhibits high electrical conductivity, and must be different from the metal oxide constituting the semiconductor.
　その理由は、ｐ型半導体素子と金属とがオーミック接触を形成できないため、金属的な電気伝導挙動を示す導電性金属酸化物から構成される焼結体を介して半導体素子と電極等とを接合することによって、接合界面の抵抗を小さくすることができるからである。なお、半導体素子と金属との接合がオーミック接触になる場合には、金属粉末のみの使用であっても、接合界面の抵抗は小さくなる。 The reason is that since the p-type semiconductor element and the metal cannot form an ohmic contact, the semiconductor element and the electrode are joined via a sintered body made of a conductive metal oxide exhibiting a metallic electric conduction behavior. This is because the resistance at the bonding interface can be reduced. In addition, when the junction between the semiconductor element and the metal is in ohmic contact, the resistance at the junction interface is reduced even when only the metal powder is used.
　使用可能なｐ型導電性金属酸化物としては、特に限定されず、ｐ型半導体の種類、共通電極又は電極として使用する金属の種類に応じて適宜変更する。例えば、ＳｒＲｕＯ３、ＲｅＯ３、Ｃｕ２Ｏ、ＣｕＯが挙げられる。本発明においては、これらのｐ型導電性金属酸化物の中でも、ＳｒＲｕＯ３を使用することが好ましい。電極等とｐ型半導体素子との接合がオーミック接触になりやすい傾向にあるからである。 The p-type conductive metal oxide that can be used is not particularly limited, and is appropriately changed according to the type of p-type semiconductor, the type of metal used as a common electrode or an electrode. For example, SrRuO 3 , ReO 3 , Cu 2 O, and CuO can be mentioned. In the present invention, among these p-type conductive metal oxides, it is preferable to use SrRuO 3 . This is because the junction between the electrode and the p-type semiconductor element tends to be in ohmic contact.
　また、ｎ型半導体素子と電極等との間に配置されるｎ型導電性金属酸化物粉末を構成するｎ型導電性金属酸化物とは、共通電極及び電極とオーミック接触を形成するものであり、電気伝導の温度特性が金属的挙動を示す物質を意味する。該導電性金属酸化物としては、ｎ型で高い電気伝導を示すものであることを特徴とし、上記ｎ型半導体を構成する材料とは異なるものを用いる必要がある。その理由はｐ型半導体の場合と同様である。 The n-type conductive metal oxide constituting the n-type conductive metal oxide powder disposed between the n-type semiconductor element and the electrode forms an ohmic contact with the common electrode and the electrode. In other words, it means a substance whose temperature characteristic of electrical conduction shows metallic behavior. The conductive metal oxide is n-type and exhibits high electrical conductivity, and it is necessary to use a material different from the material constituting the n-type semiconductor. The reason is the same as in the case of a p-type semiconductor.
　使用可能なｎ型導電性金属酸化物としては、特に限定されず、ｎ型半導体の種類、共通電極又は電極として使用する金属の種類に応じて適宜変更する。例えば、Ｉｎ２Ｏ３、ＳｎＯ２、Ｉｎ２Ｏ３－ＳｎＯ２、もしくはＮｂ又はＬａドープＳｒＴｉＯ３、ＺｎＯが挙げられる。電極等とｎ型半導体の半導体素子との接合がオーミック接触になりやすい傾向にあるからである。 The n-type conductive metal oxide that can be used is not particularly limited, and is appropriately changed depending on the type of the n-type semiconductor, the type of metal used as the common electrode or the electrode. For example, In 2 O 3 , SnO 2 , In 2 O 3 —SnO 2 , or Nb or La-doped SrTiO 3 , ZnO can be used. This is because the junction between the electrode and the n-type semiconductor element tends to be in ohmic contact.
　金属粉末、導電性金属酸化物粉末（以後、金属粉末等と総称することもある）の粒径は、焼結体の緻密さに影響を与える。上記粒径が大きいほど緻密な焼結体になりにくくなる傾向がある。所望の程度に緻密な焼結体を得ることができれば、上記粒径は特に限定されないが、２０μｍ以下であることが好ましく、さらに３μｍ以下であることがより好ましく、ナノ粒子を使用することもできる。 The particle size of the metal powder and conductive metal oxide powder (hereinafter sometimes collectively referred to as metal powder etc.) affects the density of the sintered body. The larger the particle size, the more difficult it becomes to be a dense sintered body. The particle diameter is not particularly limited as long as a sintered body dense to a desired level can be obtained, but is preferably 20 μm or less, more preferably 3 μm or less, and nanoparticles can also be used. .
　金属粉末等は、圧粉体にして用いることが好ましい。圧粉体とは金属粉末等に圧力を加えて押し固めたものを指す。圧粉体は、例えば、圧粉成形により作製することができる。圧粉体を電極等と半導体素子との間に挟み込み、放電プラズマ法を用いて焼結し緻密化することで、電極等と半導体素子とを接合させることが容易になる。 The metal powder is preferably used as a green compact. The green compact refers to a metal powder or the like that is pressed and hardened. The green compact can be produced, for example, by compacting. By sandwiching the green compact between the electrode or the like and the semiconductor element, and sintering and densifying using the discharge plasma method, it becomes easy to join the electrode or the like and the semiconductor element.
　半導体素子を電極等で挟む方向に圧力を印加しながら、圧力が印加される方向と平行な方向に直流パルス電流を印加すると、上記のような金属粉末等や圧粉体内で、粒子間に放電プラズマが発生する。この放電プラズマによる加熱で金属粉末等や圧粉体は焼結体になる（放電プラズマ焼結法による焼結体の製造）。金属粉末等や圧粉体は、焼結体になることで、電極等や、半導体素子と接着する。その結果、半導体素子と電極等との間が接合される。 When applying a DC pulse current in a direction parallel to the direction in which the pressure is applied while applying pressure in the direction in which the semiconductor element is sandwiched between electrodes, discharge occurs between the particles in the above metal powder or green compact. Plasma is generated. The metal powder or the green compact becomes a sintered body by the heating by the discharge plasma (manufacture of the sintered body by the discharge plasma sintering method). A metal powder or the like or a green compact is bonded to an electrode or the like or a semiconductor element by forming a sintered body. As a result, the semiconductor element and the electrode are joined.
　金属粉末等や圧粉体の焼結体と、電極等との接着は、両者ともに金属材料であるため容易に進む。また、金属粉末等や圧粉体の焼結体と、半導体素子との接着は、金属粉末等の粒子表面の酸化被膜が、半導体素子の表面と相互作用することにより進むと推測される。 Adhesion between a sintered body of metal powder or green compact and an electrode or the like easily proceeds because both are metal materials. In addition, the adhesion between the sintered body of metal powder or the like or the green compact and the semiconductor element is presumed to proceed by the interaction of the oxide film on the particle surface of the metal powder or the like with the surface of the semiconductor element.
　金属粉体を単独で用いた場合には、焼結体は電極の一部となる。例えば、電極等としてニッケル（Ｎｉ）プレートを用い、金属粉末としてニッケル粉末を用いた場合には、焼結によりニッケルのバルク体となり、焼結体はニッケルプレートと一体化する。
　金属粉末と導電性金属酸化物粉末の混合粉末を用いる場合には、混合粉末の焼結体は、金属と導電性金属酸化物のコンポジット電極になり、電極等と半導体素子の間の電極としてモジュールの一部となる。 When the metal powder is used alone, the sintered body becomes a part of the electrode. For example, when a nickel (Ni) plate is used as an electrode or the like and nickel powder is used as a metal powder, the bulk of nickel is formed by sintering, and the sintered body is integrated with the nickel plate.
When a mixed powder of metal powder and conductive metal oxide powder is used, the sintered body of the mixed powder becomes a composite electrode of metal and conductive metal oxide, and a module as an electrode between the electrode and the semiconductor element Part of
　この方法によれば、π型構造の熱電変換モジュールを、一度の製造工程で複数個製造することができる。したがって、従来の熱電変換モジュールの製造方法と比較して、本発明の熱電変換モジュールの製造方法は、生産性が高い。 According to this method, a plurality of π-type thermoelectric conversion modules can be manufactured in a single manufacturing process. Therefore, compared with the manufacturing method of the conventional thermoelectric conversion module, the manufacturing method of the thermoelectric conversion module of this invention has high productivity.
　また、ｐ型半導体素子及びｎ型半導体素子は、上記接合のための放電プラズマによる加熱によって熱膨張する。ｐ型半導体素子の熱膨張係数とｎ型半導体素子の熱膨張係数とが異なると、膨張しやすい方の半導体素子が損傷することが想定される。しかしながら、本発明の製造方法においては、金属粉末等又は圧粉体が緩衝材としての役割を果たすため、ｐ型半導体素子の熱膨張係数とｎ型半導体素子の熱膨張係数との差に起因する半導体素子の損傷が抑えられる。 Further, the p-type semiconductor element and the n-type semiconductor element are thermally expanded by heating with the discharge plasma for the above-described bonding. If the thermal expansion coefficient of the p-type semiconductor element and the thermal expansion coefficient of the n-type semiconductor element are different, it is assumed that the semiconductor element that is likely to expand is damaged. However, in the manufacturing method of the present invention, metal powder or the like or the green compact plays a role as a buffer material, and thus is caused by the difference between the thermal expansion coefficient of the p-type semiconductor element and the thermal expansion coefficient of the n-type semiconductor element. Damage to the semiconductor element can be suppressed.
　また、ｐ型導電性金属酸化物粉末の使用により以下の効果も奏される。ｐ型半導体素子として、金属酸化物を主成分とする焼結体を用いた場合、電極等とｐ型半導体素子との接合がオーミック接触になりにくい傾向にある。そこで、電極等とｐ型半導体素子との接合がオーミック接触になるように、ｐ型導電性金属酸化物粉末、金属粉末とｐ型導電性金属酸化物粉末の混合物を用いることができる。ここで、ｐ型導電性金属酸化物粉末、又は金属粉末とｐ型導電性金属酸化物粉末の混合物を圧粉成形してなる圧粉体を用いても同様の効果が得られる。なお、ｎ型半導体素子とｎ型導電性金属酸化物についても同様のことが言える。 Moreover, the following effects are also exhibited by using p-type conductive metal oxide powder. When a sintered body containing a metal oxide as a main component is used as the p-type semiconductor element, the junction between the electrode and the p-type semiconductor element tends not to be in ohmic contact. Therefore, p-type conductive metal oxide powder, or a mixture of metal powder and p-type conductive metal oxide powder can be used so that the junction between the electrode and the p-type semiconductor element is in ohmic contact. Here, the same effect can be obtained by using a green compact formed by compacting a p-type conductive metal oxide powder or a mixture of a metal powder and a p-type conductive metal oxide powder. The same applies to the n-type semiconductor element and the n-type conductive metal oxide.
　ｐ型半導体素子と電極等との接合においては、金属粉末とｐ型導電性金属酸化物粉末の混合物を用いることが好ましい。特に、金属粉末とｐ型導電性金属酸化物粉末との体積比（金属粉末／ｐ型導電性金属酸化物粉末）は３／７～９／１であることが好ましい。上記体積比が３／７以上であれば混合物の焼結度を高め、熱電素子と電極の接合が可能となるという理由で好ましく、９／１以下であればオーミック接触を得る事が容易となるという理由で好ましい。より好ましい上記体積比の範囲は５／５～７／３である。なお、金属粉末とｎ型導電性金属酸化物についても同様のことが言える。 In the joining of the p-type semiconductor element and the electrode or the like, it is preferable to use a mixture of metal powder and p-type conductive metal oxide powder. In particular, the volume ratio of the metal powder to the p-type conductive metal oxide powder (metal powder / p-type conductive metal oxide powder) is preferably 3/7 to 9/1. If the volume ratio is 3/7 or more, it is preferable because the degree of sintering of the mixture is increased and the thermoelectric element and the electrode can be joined. If it is 9/1 or less, ohmic contact can be easily obtained. This is preferable. A more preferable range of the volume ratio is 5/5 to 7/3. The same applies to the metal powder and the n-type conductive metal oxide.
　また、これらのｐ型導電性金属酸化物粉末を用いることで、電極等と、ｐ型半導体素子との接合が強固になるため好ましい。 It is also preferable to use these p-type conductive metal oxide powders because the bonding between the electrode and the p-type semiconductor element becomes strong.
　なお、放電プラズマ焼結を行う際の他の焼結条件は、使用する材料、材料の形状等に応じて適宜変更する。 It should be noted that other sintering conditions when performing discharge plasma sintering are appropriately changed according to the material used, the shape of the material, and the like.
　本発明の製造方法において、ｐ型半導体素子として金属酸化物を主成分とする焼結体を用い、ｎ型半導体素子としてドーパントを含むマグネシウムシリサイドを主成分とする焼結体又はマグネシウムシリサイドを主成分とする焼結体を用いれば、本発明の熱電変換モジュールを製造することができる。 In the manufacturing method of the present invention, a sintered body mainly composed of a metal oxide is used as a p-type semiconductor element, and a sintered body mainly composed of magnesium silicide containing a dopant is used as an n-type semiconductor element. When the sintered body is used, the thermoelectric conversion module of the present invention can be manufactured.
　本発明の熱電変換モジュールは、ｐ型半導体素子、ｎ型半導体素子ともに耐熱性に優れる材料からなる。したがって、本発明の熱電変換モジュールは、６００℃程度の高温環境下でも使用できる。また、本発明の熱電変換モジュールに使用されるｐ型半導体素子、ｎ型半導体素子はともに熱電変換材料としての性能が高い。
　特に、ｐ型半導体素子の製造に用いる金属酸化物としては、ＮａｘＣｏＯ２、ＣａＣｏ２Ｏ４、ＣｕＹＯ２、ＳｒＲｕＯ３、及びＳｒ２ＲｕＯ４から選択されるものの使用が好ましい。また、例えば、ＣｕＹＯ２ではＣａ、Ｍｇ、Ｓｒ等の２価のアルカリ土類金属をドープしても好ましく、酸素を過剰にしてＣｕＹＯ２＋ｘにしても好ましい。また、ＳｒＲｕＯ３及びＳｒ２ＲｕＯ４では、Ｎｂをドープしても好ましい。また、マグネシウムシリサイドに含まれるドーパントとしては、Ｓｂ、Ａｌから選択される少なくとも一種の元素が好ましい。 The thermoelectric conversion module of the present invention is made of a material having excellent heat resistance for both the p-type semiconductor element and the n-type semiconductor element. Therefore, the thermoelectric conversion module of the present invention can be used even in a high temperature environment of about 600 ° C. Moreover, both the p-type semiconductor element and the n-type semiconductor element used in the thermoelectric conversion module of the present invention have high performance as a thermoelectric conversion material.
In particular, the metal oxide used for the production of the p-type semiconductor element is preferably one selected from Na x CoO 2 , CaCo 2 O 4 , CuYO 2 , SrRuO 3 , and Sr 2 RuO 4 . Further, for example, CuYO 2 is preferably doped with a divalent alkaline earth metal such as Ca, Mg, Sr, etc., and is preferably made into CuYO 2 + x by excess oxygen. SrRuO 3 and Sr 2 RuO 4 are preferably doped with Nb. The dopant contained in magnesium silicide is preferably at least one element selected from Sb and Al.
　なお、本発明の熱電変換モジュールは、上述の本発明の製造方法以外の方法で製造してもよい。しかし、本発明の方法で製造することが以下の点から好ましい。
　第一に、上述の通り、本発明の製造方法により、本発明の熱電変換モジュールを製造することで、高い発電性能を備えるとともに高温環境下で使用可能な熱電変換モジュールを、高い生産性で製造することができる。
　第二に、従来から行われているペーストを用いる方法、はんだを用いる方法では、これらの材料が高温での使用に耐えることができない場合も多いが、金属粉末や導電性金属酸化物粉末の使用により、ペーストやはんだのような耐熱性の問題が生じることはほとんどない。 In addition, you may manufacture the thermoelectric conversion module of this invention by methods other than the manufacturing method of the above-mentioned this invention. However, the production by the method of the present invention is preferable from the following points.
First, as described above, by manufacturing the thermoelectric conversion module of the present invention by the manufacturing method of the present invention, a thermoelectric conversion module that has high power generation performance and can be used in a high temperature environment is manufactured with high productivity. can do.
Secondly, conventional methods using paste and solder often do not allow these materials to withstand use at high temperatures, but use metal powders or conductive metal oxide powders. Therefore, there is almost no problem of heat resistance such as paste and solder.
　以下、実施例を示し、本発明を具体的に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.
＜ｎ型半導体素子の製造＞
　ドーパントとしてＳｂを０．５質量％含むマグネシウムシリサイド（ユニオンマテリアル株式会社製、ＷＯ２０１１／００２０３５の実施例５のものを使用）をアルミナ乳鉢で粉砕し、東京スクリーン株式会社製の７５μｍのふるいを用いて分級して、原料粉末とした。この原料粉末を、放電プラズマ焼結装置（住友石炭鉱業株式会社製、Ｄｒ．Ｓｉｎｔｅｒ　ＬａｂＳＰＳ－５１５）を使用して焼結した。焼結条件は、グラファイト型に原料粉末を充填し、表１に示す予備加圧力を印加し、一軸加圧成形を行いながら通電し、表１に示す昇温速度で原料粉末を表１に示す保持温度まで加熱し、この保持温度で表１に示す保持時間加熱処理して焼結体を製造した。 <Manufacture of n-type semiconductor elements>
Magnesium silicide containing 0.5% by mass of Sb as a dopant (Union Material Co., Ltd., using Example 5 of WO2011 / 002035) is pulverized in an alumina mortar and using a 75 μm sieve made by Tokyo Screen Co., Ltd. Classification was performed to obtain a raw material powder. The raw material powder was sintered using a discharge plasma sintering apparatus (Dr. Sinter LabSPS-515, manufactured by Sumitomo Coal Mining Co., Ltd.). Sintering conditions are as follows. Raw material powder is filled in a graphite mold, pre-pressurization shown in Table 1 is applied, electricity is applied while performing uniaxial pressure molding, and raw material powder is shown in Table 1 at a temperature increase rate shown in Table 1. The sintered body was manufactured by heating to the holding temperature and heat treatment at the holding temperature shown in Table 1 for the holding time.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　条件１の焼結体～条件６の焼結体の外観を目視により観察した。条件１の焼結体は割れ、条件２の焼結体～条件３の焼結体は表面に亀裂が生じることが確認された。表面に亀裂の確認されなかった条件４の焼結体～条件６の焼結体の密度を測定した。条件４の焼結体の密度は９４．５％、条件５の焼結体の密度は９７．２％、条件６の焼結体の密度は９９．７％であった。条件６の焼結体が最も緻密であることが確認された。 The appearance of the sintered body of Condition 1 to the sintered body of Condition 6 was visually observed. It was confirmed that the sintered body of condition 1 was cracked, and the sintered bodies of condition 2 to condition 3 were cracked on the surface. The density of the sintered bodies of Condition 4 to Condition 6 in which no cracks were confirmed on the surface was measured. The density of the sintered body under condition 4 was 94.5%, the density of the sintered body under condition 5 was 97.2%, and the density of the sintered body under condition 6 was 99.7%. It was confirmed that the sintered body of Condition 6 was the most dense.
　条件１～条件６の結果に基づいて、最適な焼結条件を決定し、この条件で熱電変換モジュールの製造に使用するｎ型半導体素子を得た。具体的な条件は、予備加圧力が５０ＭＰａ、保持温度が８００℃、保持時間が１分、昇温速度が０～６００℃の範囲は１００℃／分、６００～７００℃の範囲は５０℃／分、７００～８００℃の範囲は３０℃／分である。なお、後述する熱電変換モジュールの製造においては、焼結体から５．４ｍｍ（縦）×１０．５ｍｍ（横）×８．５ｍｍ（高さ）の試料を切り出して用いた。 Based on the results of Condition 1 to Condition 6, the optimum sintering condition was determined, and an n-type semiconductor element used for manufacturing the thermoelectric conversion module was obtained under this condition. Specifically, the preliminary pressurizing force is 50 MPa, the holding temperature is 800 ° C., the holding time is 1 minute, the temperature rising rate is 0 to 600 ° C. in the range of 100 ° C./min, and the temperature in the range of 600 to 700 ° C. is 50 ° C. / Min, the range of 700-800 ° C. is 30 ° C./min. In the manufacture of the thermoelectric conversion module described later, a sample of 5.4 mm (length) × 10.5 mm (width) × 8.5 mm (height) was cut out from the sintered body and used.
＜ｐ型半導体素子の製造＞
　エチレングリコールモノメチルエーテル（和光純薬株式会社製）に、クエン酸１水和物（和光純薬株式会社製）を加え攪拌した後、無水酢酸ナトリウム（和光純薬株式会社製）、硝酸コバルト（和光純薬株式会社製）を大気下常温で加え攪拌することで出発溶液を得た。出発溶液は、オイルバスで６０℃、１時間還流をした後、大気中の炉内で１０５℃、８時間の条件で乾燥させ、続いて４５０℃、２時間の条件で熱処理を加えることでＮａｘＣｏＯ２試料の前駆体を作成した。なお、熱処理は全てアルミナ坩堝で行った。 <Manufacture of p-type semiconductor elements>
After adding citric acid monohydrate (Wako Pure Chemical Industries, Ltd.) and stirring to ethylene glycol monomethyl ether (Wako Pure Chemical Industries, Ltd.), anhydrous sodium acetate (Wako Pure Chemical Industries, Ltd.), cobalt nitrate (Japanese A starting solution was obtained by adding and stirring at room temperature in the atmosphere. The starting solution was refluxed in an oil bath at 60 ° C. for 1 hour, dried in an oven in the atmosphere at 105 ° C. for 8 hours, and then heat treated at 450 ° C. for 2 hours to add Na. x CoO 2 sample precursors were prepared. All heat treatments were performed in an alumina crucible.
　上記前駆体の一部を取り出し、ＮａＣｌ及びＫＣｌと重量比が２：１：１（前駆体：ＮａＣｌ：ＫＣｌ）になる割合で混合した。この混合物を試料として坩堝に入れ、アロンセラミックスで密封して一日放置した後、アロンセラミックスを硬化させるために熱処理を行った。温度条件は１００℃まで７５分で昇温、２時間保持、２００℃まで５０分で昇温、２時間保持、３００℃まで２０分で昇温、１時間保持、６０分で室温まで冷却を行った。次に板状結晶作製のための熱処理を行った。熱処理条件は、１１００℃まで１００分で昇温、１２分保持、５時間かけて７００℃までゆっくり冷却させ、室温まで７０分かけて冷却を行った。試料を取りだし、蒸留水でＮａＣｌとＫＣｌを溶かしアスペクト比が５０の板状結晶を得た。電子顕微鏡写真により、板状結晶は、構造異方性が高く、平均径が５～１０μｍで均質な厚さで生成していることが確認された。 A part of the precursor was taken out and mixed with NaCl and KCl at a weight ratio of 2: 1: 1 (precursor: NaCl: KCl). This mixture was placed in a crucible as a sample, sealed with Aron ceramics and allowed to stand for a day, and then heat treated to cure the Aron ceramics. Temperature conditions: temperature rise to 100 ° C in 75 minutes, hold for 2 hours, heat up to 200 ° C in 50 minutes, hold for 2 hours, heat up to 300 ° C in 20 minutes, hold for 1 hour, cool to room temperature in 60 minutes It was. Next, heat treatment for producing plate crystals was performed. As heat treatment conditions, the temperature was raised to 1100 ° C. in 100 minutes, held for 12 minutes, slowly cooled to 700 ° C. over 5 hours, and cooled to room temperature over 70 minutes. A sample was taken out and NaCl and KCl were dissolved in distilled water to obtain a plate-like crystal having an aspect ratio of 50. Electron micrographs confirmed that the plate-like crystals had a high structural anisotropy, an average diameter of 5 to 10 μm and a uniform thickness.
　グラファイト型に、ＮａｘＣｏＯ２試料の前駆体及び板状結晶を充填し、５０ＭＰａの予備加圧力を印加し、一軸加圧成形を行いながら通電し、７００℃まで７分で昇温し、７００～８５０℃まで３分で昇温し、この温度で１０分間加熱して焼結体を製造した。この焼結体をｐ型半導体素子として、以下の熱電変換モジュールの製造に用いた。具体的には焼結体から４．５ｍｍ（縦）×９．５ｍｍ（横）×８．５ｍｍ（高さ）の試料を切り出して用いた。 A graphite mold is filled with a precursor of Na x CoO 2 sample and a plate-like crystal, a pre-pressurizing pressure of 50 MPa is applied, energized while performing uniaxial pressing, and the temperature is raised to 700 ° C. in 7 minutes. The temperature was raised to ˜850 ° C. in 3 minutes and heated at this temperature for 10 minutes to produce a sintered body. This sintered body was used as a p-type semiconductor element for manufacturing the following thermoelectric conversion module. Specifically, a 4.5 mm (vertical) × 9.5 mm (horizontal) × 8.5 mm (height) sample was cut out from the sintered body and used.
＜実施例１＞
　０．５ｇのニッケル金属の粉末（２～３μｍ、純度９９．９％）を、内径２０ｍｍ×高さ４０ｍｍの円筒形金型に充填し、加圧力３０ＭＰａの条件で圧粉体を製造し、１３ｍｍ×５ｍｍ×０．５ｍｍに切り出した。また、共通電極及び電極としてはニッケルプレートを用いた。圧粉体、ニッケルプレート、ｎ型半導体素子、ｐ型半導体素子を用いて、以下の方法で実施例１の熱電変換モジュールを製造した。 <Example 1>
0.5 g of nickel metal powder (2 to 3 μm, purity 99.9%) is filled into a cylindrical mold having an inner diameter of 20 mm and a height of 40 mm, and a green compact is produced under a pressure of 30 MPa. Cut out to × 5 mm × 0.5 mm. Moreover, the nickel plate was used as a common electrode and an electrode. Using the green compact, nickel plate, n-type semiconductor element, and p-type semiconductor element, the thermoelectric conversion module of Example 1 was manufactured by the following method.
　先ず、２枚のニッケルプレートの上面に、それぞれ圧粉体を配置した。次いで、一方の圧粉体上に５．４ｍｍ（縦）×１０．５ｍｍ（横）の面が接するようにｎ型半導体素子を配置し、他方の圧粉体上に４．５ｍｍ（縦）×９．５ｍｍ（横）の面が接するようにｐ型半導体素子を配置した。次いで、圧粉体とｎ型、ｐ型半導体素子とが接する面の裏面に圧粉体をそれぞれ配置した。これらの圧粉体上に共通電極となる１枚のニッケルプレートを、ニッケルプレートの底面が圧粉体と接するように配置した。
　次いで、電極として用いる２枚のニッケルプレートの底面、共通電極として用いる１枚のニッケルプレートの上面に、それぞれグラファイト電極を配置した。
　最後に、グラファイト電極間に予備加圧力１５ＭＰａを印加し、一軸加圧成形を行いながら通電し、１００℃／分の昇温速度で６００℃まで圧粉体を加熱し、この温度で２分間加熱処理して熱電変換モジュールを製造した。 First, the green compacts were respectively arranged on the upper surfaces of the two nickel plates. Next, an n-type semiconductor element is arranged so that the surface of 5.4 mm (vertical) × 10.5 mm (horizontal) is in contact with one green compact, and 4.5 mm (vertical) × on the other green compact. The p-type semiconductor element was arranged so that the surface of 9.5 mm (horizontal) was in contact. Next, the green compacts were respectively disposed on the back surfaces of the surfaces where the green compacts contact the n-type and p-type semiconductor elements. One nickel plate serving as a common electrode was placed on these green compacts so that the bottom surface of the nickel plate was in contact with the green compact.
Next, graphite electrodes were respectively disposed on the bottom surfaces of two nickel plates used as electrodes and on the top surface of one nickel plate used as a common electrode.
Finally, pre-pressurization pressure of 15 MPa is applied between the graphite electrodes, electricity is applied while performing uniaxial pressing, and the green compact is heated to 600 ° C. at a rate of 100 ° C./min, and heated at this temperature for 2 minutes. The thermoelectric conversion module was manufactured by processing.
＜発電性能の評価＞
　発電性能の評価は、市販の熱電特性評価装置（アルバック理工社製、「ＺＥＮ－２」）を用いて行った。具体的には、ニッケルプレートの上に熱電対を設置して、高温側の表面温度と低温側の表面温度とを測定した。そして、熱電変換モジュールのニッケルプレート間に一定電流を印加して、降下電圧を測定した。最後に降下電圧と一定電流の値から電力を算出した。測定条件と結果とを表２、図２に示した。なお、低温側の表面温度は全て１００℃である。 <Evaluation of power generation performance>
The power generation performance was evaluated using a commercially available thermoelectric property evaluation apparatus (“ZEN-2” manufactured by ULVAC-RIKO). Specifically, a thermocouple was installed on the nickel plate, and the surface temperature on the high temperature side and the surface temperature on the low temperature side were measured. Then, a constant current was applied between the nickel plates of the thermoelectric conversion module, and the voltage drop was measured. Finally, power was calculated from the voltage drop and constant current. The measurement conditions and results are shown in Table 2 and FIG. Note that the surface temperature on the low temperature side is all 100 ° C.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　上記の表２に示す評価結果から、本発明の熱電変換モジュールは、２００～６００℃程度の環境下で使用できることが確認された。また、本発明の熱電変換モジュールは、温度差が５００℃の条件における、電力の最大値が６．６４５ｍＷであることから、発電性能が一般的な熱電変換モジュールと同等であることが確認された。 From the evaluation results shown in Table 2 above, it was confirmed that the thermoelectric conversion module of the present invention can be used in an environment of about 200 to 600 ° C. Further, the thermoelectric conversion module of the present invention has a power generation performance of 6.645 mW under a temperature difference of 500 ° C. Therefore, it was confirmed that the power generation performance is equivalent to a general thermoelectric conversion module. .
＜実施例２＞
　ｐ型半導体素子と電極等との接合において、圧粉体を製造するためのニッケル金属の粉末を、ニッケル金属の粉末と下記の方法で製造されたＳｒＲｕＯ３の粉末との混合物（ニッケル金属の粉末の質量／ＳｒＲｕＯ３の粉末の質量＝７／３）に変更した以外は実施例１と同様の方法で実施例２の熱電変換モジュールを製造した。 <Example 2>
In joining a p-type semiconductor element and an electrode or the like, a nickel metal powder for producing a green compact is mixed with a mixture of nickel metal powder and SrRuO 3 powder produced by the following method (nickel metal powder). Mass / SrRuO 3 powder mass = 7/3). A thermoelectric conversion module of Example 2 was produced in the same manner as in Example 1.
＜ＳｒＲｕＯ３の粉末の製造方法＞
　蒸留水に、クエン酸１水和物（和光純薬株式会社製）を加え攪拌した後、酢酸ストロンチウム（関東化学株式会社製）を大気下常温で加え攪拌し、この溶液に塩化ルテニウム（ＩＩ）（フルヤ金属株式会社製）を乾燥窒素下常温で加え攪拌することで出発溶液を得た。出発溶液は、大気中の炉内で８０℃、８時間の条件で乾燥させ、続いて５５０℃、５時間の条件で熱処理を加えることでＳｒＲｕＯ３試料の前駆体を作成した。なお、熱処理は全てアルミナ坩堝で行った。 <Method for Producing SrRuO 3 Powder>
After adding citric acid monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) to distilled water and stirring, strontium acetate (manufactured by Kanto Chemical Co., Ltd.) was added and stirred at room temperature in the atmosphere, and ruthenium (II) chloride was added to this solution. (Fluya Metal Co., Ltd.) was added at room temperature under dry nitrogen and stirred to obtain a starting solution. The starting solution was dried in an atmospheric furnace at 80 ° C. for 8 hours, followed by heat treatment at 550 ° C. for 5 hours to prepare a precursor of a SrRuO 3 sample. All heat treatments were performed in an alumina crucible.
　ニッケル金属の粉末と混合するＳｒＲｕＯ３の粉末は、上記ＳｒＲｕＯ３前駆体粉末をさらに大気炉内で１０００℃、５時間の条件で熱処理を加えることで、粒径が１０μｍ以下のｐ型導電性金属酸化物粉末とした。 The SrRuO 3 powder mixed with the nickel metal powder is a p-type conductive metal having a particle size of 10 μm or less by further heat-treating the SrRuO 3 precursor powder in an atmospheric furnace at 1000 ° C. for 5 hours. An oxide powder was obtained.
＜実施例３＞
　ニッケル金属の粉末の質量／ＳｒＲｕＯ３の粉末の質量＝７／３を、ニッケル金属の粉末の質量／ＳｒＲｕＯ３の粉末の質量＝６／４に変更した以外は、実施例２と同様の方法で実施例３の熱電変換モジュールを製造した。 <Example 3>
The mass of the nickel metal powder / the mass of the SrRuO 3 powder = 7/3 was changed to the mass of the nickel metal powder / the mass of the SrRuO 3 powder = 6/4 in the same manner as in Example 2. The thermoelectric conversion module of Example 3 was manufactured.
＜実施例４＞
　ニッケル金属の粉末の質量／ＳｒＲｕＯ３の粉末の質量＝７／３を、ニッケル金属の粉末の質量／ＳｒＲｕＯ３の粉末の質量＝５／５に変更した以外は、実施例２と同様の方法で実施例３の熱電変換モジュールを製造した。 <Example 4>
The mass of the nickel metal powder / the mass of the SrRuO 3 powder = 7/3 was changed to the mass of the nickel metal powder / the mass of the SrRuO 3 powder = 5/5 in the same manner as in Example 2. The thermoelectric conversion module of Example 3 was manufactured.
＜発電性能の評価＞
　実施例２～４の熱電変換モジュールの発電性能の評価を、実施例１の熱電変換モジュールの発電性能の評価と同様の方法で行った。実施例２の測定条件及び評価結果を表３及び図３に、実施例３の測定条件及び評価結果を表４及び図４に、実施例４の測定条件及び評価結果を表５及び図５に示した。なお、低温側の表面温度は全て１００℃である。 <Evaluation of power generation performance>
Evaluation of the power generation performance of the thermoelectric conversion modules of Examples 2 to 4 was performed in the same manner as the evaluation of the power generation performance of the thermoelectric conversion module of Example 1. The measurement conditions and evaluation results of Example 2 are shown in Table 3 and FIG. 3, the measurement conditions and evaluation results of Example 3 are shown in Tables 4 and 4, and the measurement conditions and evaluation results of Example 4 are shown in Tables 5 and 5. Indicated. Note that the surface temperature on the low temperature side is all 100 ° C.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　実施例１の熱電変換モジュールの発電性能と、実施例２～４の熱電変換モジュールの発電性能とを比較すると、電極等とｐ型半導体素子とを接合するための粉末として、金属粉末とｐ型導電性金属酸化物粉末との混合物を用いることで、熱電変換モジュールの発電性能が向上することが確認された。なお、実施例で使用しているマグネシウムシリサイドは、金属電極と接合しても接合界面の抵抗が小さいため、ｎ型導電性金属酸化物粉末を用いなくても、発電性能の大きな低下にはつながらない。ただし、ｎ型半導体素子と金属電極との接合において、接合界面の抵抗が大きくなる場合には、ｎ型導電性金属酸化物粉末を使用することで、接合界面の抵抗を小さくすることができると考えられる。 When the power generation performance of the thermoelectric conversion module of Example 1 is compared with the power generation performance of the thermoelectric conversion modules of Examples 2 to 4, metal powder and p-type are used as powders for joining the electrode and the p-type semiconductor element. It was confirmed that the power generation performance of the thermoelectric conversion module was improved by using the mixture with the conductive metal oxide powder. In addition, since the magnesium silicide used in the examples has a small resistance at the bonding interface even when bonded to the metal electrode, even if n-type conductive metal oxide powder is not used, the power generation performance is not greatly reduced. . However, when the resistance of the bonding interface increases in the bonding between the n-type semiconductor element and the metal electrode, the resistance of the bonding interface can be reduced by using the n-type conductive metal oxide powder. Conceivable.
　表１と表２～４とから、降下電圧に関しては、実施例２～４の熱電変換モジュールと実施例１の熱電変換モジュールとでほとんど差がないことが確認された。一方、電流値に関しては、実施例２～４の熱電変換モジュールを流れる電流は、実施例１の熱電変換モジュールを流れる電流と比較して非常に高いことが確認された。これらの結果から、実施例２～４の熱電変換モジュールは、実施例１の熱電変換モジュールと比較して、電極等と半導体素子との界面の抵抗が非常に小さいことが確認できる。 From Table 1 and Tables 2 to 4, it was confirmed that there was almost no difference in voltage drop between the thermoelectric conversion modules of Examples 2 to 4 and the thermoelectric conversion module of Example 1. On the other hand, regarding the current value, it was confirmed that the current flowing through the thermoelectric conversion modules of Examples 2 to 4 was very high compared to the current flowing through the thermoelectric conversion module of Example 1. From these results, it can be confirmed that the thermoelectric conversion modules of Examples 2 to 4 have very low resistance at the interface between the electrode and the like and the semiconductor element as compared with the thermoelectric conversion module of Example 1.
＜実施例５＞
　ｐ型半導体素子として、ＳｒＲｕＯ３焼結体を用いた以外は、実施例１の熱電変換モジュールと同様の方法で、実施例５の熱電変換モジュールを製造した。なお、具体的には、以下の方法で、熱処理されたＳｒＲｕＯ３の焼結体を製造し、この焼結体から４．５ｍｍ（縦）×９．５ｍｍ（横）×７．５ｍｍ（高さ）の試料を切り出したものをｐ型半導体素子として使用した。 <Example 5>
A thermoelectric conversion module of Example 5 was manufactured in the same manner as the thermoelectric conversion module of Example 1 except that a SrRuO 3 sintered body was used as the p-type semiconductor element. Specifically, a heat-treated sintered body of SrRuO 3 was manufactured by the following method, and 4.5 mm (length) × 9.5 mm (width) × 7.5 mm (height) from the sintered body. 1) was used as a p-type semiconductor element.
　グラファイト型に、上述のＳｒＲｕＯ３試料の前駆体を充填し、５０ＭＰａの予備加圧力を印加し、一軸加圧成形を行いながら通電し、１１００℃まで１１分で昇温し、この温度で４分間加熱して焼結体を製造した。この焼結体に対して、大気下、処理温度１３００℃、処理時間１２時間の条件で熱処理を施しＳｒＲｕＯ３焼結体を得た。 The graphite mold is filled with the above-mentioned precursor of SrRuO 3 sample, a pre-pressurizing force of 50 MPa is applied, energized while performing uniaxial pressing, and the temperature is raised to 1100 ° C. in 11 minutes, and this temperature is increased for 4 minutes. A sintered body was produced by heating. This sintered body was heat-treated in the atmosphere under the conditions of a processing temperature of 1300 ° C. and a processing time of 12 hours to obtain a SrRuO 3 sintered body.
＜発電性能の評価＞
　実施例５の熱電変換モジュールの発電性能の評価を、実施例１の熱電変換モジュールの発電性能の評価と同様の方法で行った。実施例５の測定条件及び評価結果を表６、図６に示した。なお、低温側の表面温度は全て１００℃である。 <Evaluation of power generation performance>
The power generation performance of the thermoelectric conversion module of Example 5 was evaluated in the same manner as the power generation performance of the thermoelectric conversion module of Example 1. The measurement conditions and evaluation results of Example 5 are shown in Table 6 and FIG. Note that the surface temperature on the low temperature side is all 100 ° C.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　実施例５の熱電変換モジュールの発電性能と、実施例１の熱電変換モジュールの発電性能とを比較すると、ｐ型半導体素子を構成する金属酸化物の種類を変更することで、熱電変換モジュールの発電性能が大きく向上することが確認された。 Comparing the power generation performance of the thermoelectric conversion module of Example 5 and the power generation performance of the thermoelectric conversion module of Example 1, the power generation of the thermoelectric conversion module can be achieved by changing the type of metal oxide constituting the p-type semiconductor element. It was confirmed that the performance was greatly improved.
＜実施例６＞
　出発溶液中のＮｂが５ｍｏｌ％になるように、出発溶液を製造する際にＮｂを加えた以外は実施例５と同様の方法で、実施例６の熱電変換モジュールを製造した。 <Example 6>
A thermoelectric conversion module of Example 6 was produced in the same manner as in Example 5 except that Nb was added when producing the starting solution so that Nb in the starting solution was 5 mol%.
＜発電性能の評価＞
　実施例６の熱電変換モジュールの発電性能の評価を、実施例１の熱電変換モジュールの発電性能の評価と同様の方法で行った。実施例６の測定条件及び評価結果を表７、図７に示した。なお、低温側の表面温度は全て１００℃である。 <Evaluation of power generation performance>
The power generation performance of the thermoelectric conversion module of Example 6 was evaluated in the same manner as the power generation performance of the thermoelectric conversion module of Example 1. The measurement conditions and evaluation results of Example 6 are shown in Table 7 and FIG. Note that the surface temperature on the low temperature side is all 100 ° C.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　実施例６の熱電変換モジュールの発電性能と、実施例５の熱電変換モジュールの発電性能とを比較すると、ｐ型半導体素子を構成する金属酸化物を、ドーパントを含む金属酸化物に変更することで、熱電変換モジュールの発電性能が向上することが確認された。 When comparing the power generation performance of the thermoelectric conversion module of Example 6 with the power generation performance of the thermoelectric conversion module of Example 5, the metal oxide constituting the p-type semiconductor element is changed to a metal oxide containing a dopant. It was confirmed that the power generation performance of the thermoelectric conversion module was improved.
　１　　熱電変換モジュール
　１０　ｎ型半導体素子
　１１　ｐ型半導体素子
　１２　共通電極
　１３　電極 1 thermoelectric conversion module 10 n-type semiconductor element 11 p-type semiconductor element 12 common electrode 13 electrode

Claims (13)

  1. 　ｎ型半導体素子と、ｐ型半導体素子と、前記ｎ型半導体素子の一端と前記ｐ型半導体素子の一端とが接合される共通電極と、前記ｎ型半導体素子の他端及び前記ｐ型半導体素子の他端にそれぞれ独立して接合される電極と、を備える熱電変換モジュールの製造方法であって、
    　前記ｎ型半導体素子と、前記共通電極及び電極との間に金属粉末及び／又はｎ型導電性金属酸化物粉末を配置し、
    　前記ｐ型半導体素子と、前記共通電極及び電極との間に金属粉末及び／又はｐ型導電性金属酸化物粉末を配置し、
    　前記ｎ型半導体素子及びｐ型半導体素子を前記共通電極及び前記電極で挟む方向に圧力を印加しながら、前記圧力が印加される方向と平行な方向に直流パルス電流を印加して焼結し、前記ｎ型半導体素子と前記共通電極及び電極との間及び前記ｐ型半導体素子と前記共通電極及び電極との間を接合する熱電変換モジュールの製造方法。     an n-type semiconductor element; a p-type semiconductor element; a common electrode where one end of the n-type semiconductor element and one end of the p-type semiconductor element are joined; the other end of the n-type semiconductor element; and the p-type semiconductor element An electrode that is independently joined to the other end of the thermoelectric conversion module,
    A metal powder and / or an n-type conductive metal oxide powder is disposed between the n-type semiconductor element and the common electrode and the electrode,
    A metal powder and / or a p-type conductive metal oxide powder is disposed between the p-type semiconductor element and the common electrode and the electrode,
    While applying a pressure in a direction sandwiching the n-type semiconductor element and the p-type semiconductor element between the common electrode and the electrode, a DC pulse current is applied in a direction parallel to the direction in which the pressure is applied, and sintering is performed. The manufacturing method of the thermoelectric conversion module which joins between the said n-type semiconductor element, the said common electrode, and an electrode, and between the said p-type semiconductor element, and the said common electrode and an electrode.
  2. 　前記金属粉末及び／又はｎ型導電性金属酸化物粉末、並びに前記金属粉末及び／又はｐ型導電性金属酸化物粉末は、圧粉体である請求項１に記載の熱電変換モジュールの製造方法。 The method for producing a thermoelectric conversion module according to claim 1, wherein the metal powder and / or the n-type conductive metal oxide powder, and the metal powder and / or the p-type conductive metal oxide powder are green compacts.
  3. 　前記ｎ型半導体素子と前記共通電極及び電極との間に、金属粉末とｎ型導電性金属酸化物粉末との混合物を配置し、
    　前記ｐ型半導体素子と前記共通電極及び電極との間に、金属粉末とｐ型導電性金属酸化物粉末との混合物を配置する請求項１又は２に記載の熱電変換モジュールの製造方法。     A mixture of metal powder and n-type conductive metal oxide powder is disposed between the n-type semiconductor element and the common electrode and the electrode,
    The manufacturing method of the thermoelectric conversion module of Claim 1 or 2 which arrange | positions the mixture of metal powder and p-type electroconductive metal oxide powder between the said p-type semiconductor element, the said common electrode, and electrode.
  4. 　前記ｐ型半導体素子は、前記共通電極及び前記電極との接合に用いられる前記ｐ型導電性金属酸化物と異なる金属酸化物を主成分とする焼結体であり、
    　前記ｎ型半導体素子は、Ｓｂ、Ａｌから選択される少なくとも一種の元素をドーパントとして含むマグネシウムシリサイドを主成分とする焼結体又はマグネシウムシリサイドを主成分とする焼結体である請求項１乃至３のいずれか１に記載の熱電変換モジュールの製造方法。     The p-type semiconductor element is a sintered body mainly composed of a metal oxide different from the p-type conductive metal oxide used for joining the common electrode and the electrode,
    4. The n-type semiconductor element is a sintered body mainly composed of magnesium silicide containing at least one element selected from Sb and Al as a dopant, or a sintered body mainly composed of magnesium silicide. The manufacturing method of the thermoelectric conversion module of any one of.
  5. 　前記ｐ型半導体素子は、前記金属酸化物の粉体と前記金属酸化物の板状結晶との混合物を、一軸加圧成形しながら加圧方向と平行に直流パルス電流を印加して、焼結させた焼結体である請求項４に記載の熱電変換モジュールの製造方法。 The p-type semiconductor element is sintered by applying a DC pulse current parallel to the pressing direction while uniaxially pressing a mixture of the metal oxide powder and the metal oxide plate crystal. The method for producing a thermoelectric conversion module according to claim 4, wherein the sintered body is a sintered body.
  6. 　ｎ型半導体素子と、ｐ型半導体素子と、前記ｎ型半導体素子の一端と前記ｐ型半導体素子の一端とが接合される共通電極と、前記ｎ型半導体素子の他端及び前記ｐ型半導体素子の他端にそれぞれ独立して接合される電極と、を備え、
    　前記ｐ型半導体素子の端部と前記共通電極及び電極との接合部が、金属の焼結体、金属とｐ型導電性金属酸化物の混合物の焼結体又はｐ型導電性金属酸化物の焼結体から構成され、
    　前記ｎ型半導体素子の端部と前記共通電極及び電極との接合部が、金属の焼結体、金属とｎ型導電性金属酸化物の混合物の焼結体又はｎ型導電性金属酸化物の焼結体から構成される熱電変換モジュール。     an n-type semiconductor element; a p-type semiconductor element; a common electrode where one end of the n-type semiconductor element and one end of the p-type semiconductor element are joined; the other end of the n-type semiconductor element; and the p-type semiconductor element An electrode that is independently joined to the other end of
    The junction between the end of the p-type semiconductor element and the common electrode and the electrode is a sintered body of metal, a sintered body of a mixture of metal and p-type conductive metal oxide, or p-type conductive metal oxide. Composed of a sintered body,
    The junction between the end of the n-type semiconductor element and the common electrode and the electrode is made of a metal sintered body, a sintered body of a mixture of a metal and an n-type conductive metal oxide, or an n-type conductive metal oxide. Thermoelectric conversion module composed of a sintered body.
  7. 　前記ｐ型半導体素子の端部と前記共通電極及び電極との接合部が、金属とｐ型導電性金属酸化物の混合物の焼結体から構成され、
    　前記ｎ型半導体素子の端部と前記共通電極及び電極との接合部が、金属とｎ型導電性金属酸化物の混合物の焼結体から構成される請求項６に記載の熱電変換モジュール。     The junction between the end of the p-type semiconductor element and the common electrode and the electrode is composed of a sintered body of a mixture of metal and p-type conductive metal oxide,
    The thermoelectric conversion module according to claim 6, wherein a joint portion between the end portion of the n-type semiconductor element and the common electrode and the electrode is formed of a sintered body of a mixture of a metal and an n-type conductive metal oxide.
  8. 　前記ｐ型半導体素子は、前記接合部を構成するｐ型導電性金属酸化物と異なる金属酸化物を主成分とする焼結体であり、前記ｎ型半導体素子は、マグネシウムシリサイドを主成分とする焼結体である請求項６又は７に記載の熱電変換モジュール。 The p-type semiconductor element is a sintered body whose main component is a metal oxide different from the p-type conductive metal oxide constituting the junction, and the n-type semiconductor element is mainly composed of magnesium silicide. The thermoelectric conversion module according to claim 6, which is a sintered body.
  9. 　前記マグネシウムシリサイドを主成分とする焼結体が、ドーパントを含むものである請求項８に記載の熱電変換モジュール。 The thermoelectric conversion module according to claim 8, wherein the sintered body containing magnesium silicide as a main component includes a dopant.
  10. 　前記ドーパントは、Ｓｂ、Ａｌから選択される少なくとも一種の元素である請求項９に記載の熱電変換モジュール。 The thermoelectric conversion module according to claim 9, wherein the dopant is at least one element selected from Sb and Al.
  11. 　前記ｐ型半導体素子を構成する前記金属酸化物が、ＮａｘＣｏＯ２、ＣａＣｏ２Ｏ４、ＣｕＹＯ２、ＳｒＲｕＯ３、及びＳｒ２ＲｕＯ４から選択される請求項８乃至１０のいずれか１に記載の熱電変換モジュール。 The metal oxide constituting the p-type semiconductor elements, Na x CoO 2, CaCo 2 O 4, CuYO 2, SrRuO 3, and according to any one of claims 8 to 10 selected from Sr 2 RuO 4 Thermoelectric conversion module.
  12. 　前記接合部の焼結体を構成するｐ型導電性金属酸化物がＳｒＲｕＯ３、ＲｅＯ３、Ｃｕ２Ｏ及びＣｕＯから選択される請求項６乃至１１のいずれか１に記載の熱電変換モジュール。 The thermoelectric conversion module according to any one of claims 6 to 11, wherein the p-type conductive metal oxide constituting the sintered body of the joint is selected from SrRuO 3 , ReO 3 , Cu 2 O and CuO.
  13. 　前記接合部の焼結体を構成するｎ型導電性金属酸化物がＩｎ２Ｏ３、ＳｎＯ２、Ｉｎ２Ｏ３－ＳｎＯ２、もしくはＮｂ又はＬａドープＳｒＴｉＯ３、ＺｎＯである請求項６乃至１２のいずれか１に記載の熱電変換モジュール。 The n-type conductive metal oxide constituting the sintered body of the joint is In 2 O 3 , SnO 2 , In 2 O 3 —SnO 2 , or Nb or La-doped SrTiO 3 , ZnO. The thermoelectric conversion module according to any one of the above.
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