JP5546737B2 - Manufacturing method of semiconductor substrate - Google Patents

Description

  The present invention relates to a method for producing a semiconductor substrate having a patterned thin film semiconductor layer.

  Conventionally, in order to manufacture a circuit substrate having conductive wiring on a substrate, a photoresist or the like is applied on the substrate bonded with a metal foil, a desired circuit pattern is exposed, and chemical etching is performed. A method of forming a pattern has been used. In this method, since a metal foil can be used as the conductive wiring, a volume resistivity is small and a high-performance conductive substrate can be manufactured. However, this method has many steps and is complicated. In addition, there is a disadvantage that a photoresist material is required.

On the other hand, a method of directly printing a pattern on a base material with a paint in which metal fine particles are dispersed has attracted attention. Such a method for printing a pattern directly on a substrate does not require the use of a photoresist or the like, and is a highly productive method.
From such a point of view, an organic semiconductor has attracted attention as a semiconductor that can be formed by coating, but has not been put into practical use because it has low mobility and is unstable in the atmosphere.
As a method of printing a pattern directly on a base material with a paint in which metal fine particles are dispersed, a metal pattern such as copper is formed in a pattern and then reduced and fired to obtain a metal pattern. It has been proposed to form a wiring pattern (Patent Document 1).
Specifically, the method for forming a fine copper-based wiring pattern proposed in Patent Document 1 is to draw an ultrafine pattern using a dispersion of copper oxide nanoparticles, and then make the copper oxide nanoparticles in the pattern. This is a method of forming a sintered copper-based wiring pattern having a low impedance and extremely fine corresponding to a digital high-density wiring by subjecting to a reduction treatment and firing the produced copper nanoparticles. However, Patent Document 1 does not disclose semiconductor nanoparticles and semiconductor compound metal nanoparticles.

On the other hand, Non-Patent Document 1 presents a field effect transistor having a conductive channel made of a lead selenium (PbSe) semiconductor nanocrystal using a liquid phase process as a solution-based process of an inorganic semiconductor. . Nanocrystals are insulative, and an example in which this material is formed into a pattern and then reduced with hydrazine is presented.
However, since hydrazine is explosive and dangerous, and PbSe is toxic, there is a problem in putting it to practical use.

Patent Document 2 proposes a method of manufacturing a thin film semiconductor using nanoparticles, including a step of forming a nanoparticle film on a substrate and performing a heat treatment. The step of forming a nanoparticle film includes a step of dispersing nanoparticles in a solvent and preparing a nanoparticle solution, a step of mixing a precipitant with the nanoparticle solution, and a nanoparticle solution containing the precipitant. And a step of vapor-depositing on the substrate.
Examples of the nanoparticles include HgTe, HgSe, HgS, CdTe, CdSe, CdS, ZnTe, ZnSe, ZnS, PbTe, PbSe, PbS, and ZnO.
The nanoparticle solution containing the precipitant is deposited on the substrate by any one of spin coating, dip coating, stamping, spraying, Langmuir-Blodgett, and printing. It is disclosed that it can be used. Furthermore, the example which heat-processes a nanoparticle film | membrane at 100 to 185 degreeC for 10 to 200 minutes and obtains a semiconductor layer is disclosed.
However, the method described in Patent Document 2 is not a practical method because it has low semiconductor characteristics because it is not subjected to reduction treatment, and has a relatively long heating time of 10 to 200 minutes.
That is, since the surfaces of the nanoparticles are easily oxidized, good semiconductor characteristics cannot be expressed unless the nanoparticles are sintered together after removing the oxide film on the surface of the nanoparticles by reduction treatment.

  Patent Document 3 proposes a thin film forming method for forming a thin film by applying nanoparticles to a substrate and subjecting the nanoparticles applied on the substrate to atmospheric pressure plasma processing as a thin film forming method. ing. Nanoparticles applied to the excitation gas on the substrate by supplying a gas between the opposing electrodes under an atmospheric pressure or a pressure near atmospheric pressure and generating a high-frequency electric field between the electrodes to make the gas an excitation gas Is a thin film formation method using atmospheric pressure plasma treatment. The nanoparticle is a metal atom-containing compound, and the metal atom of the metal atom-containing compound is at least one selected from the group consisting of In, Ga, Al, Sn, Ge, Sb, Bi, and Zn. A method is disclosed.

  However, the specific thin film forming method described in Patent Document 3 is a method in which a thin film is applied to a substrate by spray coating or spin coating, and the thin film is formed by an atmospheric pressure plasma method. Description of pattern printing In addition, the nanoparticles are examples relating to Sn / In composite nanoparticles, and the obtained thin film only describes a Sn / In transparent conductive film.

JP 2004-119686 A JP 2007-273949 A JP 2007-182605 A Science, 310, p86

  Under such circumstances, the present invention provides a thin film semiconductor having practically sufficient mobility using germanium (Ge) nanoparticles having excellent semiconductor characteristics (hereinafter sometimes simply referred to as “Ge nanoparticles”). It aims at providing the method of manufacturing with high productivity.

The inventors of the present invention have intensively studied a method of directly pattern-printing Ge nanoparticles on a base material without using a complicated process such as a photoresist to form a thin film semiconductor. As a result, Ge nanoparticles are formed on the base material. The present inventors have found that the above-described problem can be solved by printing a coating liquid containing the coating liquid in a pattern to form a printed layer and then firing the printed layer to form a patterned semiconductor layer. The present invention has been completed based on such findings.
That is, the present invention
(1) A semiconductor substrate on which a coating layer containing germanium (Ge) nanoparticles is printed in a pattern on a substrate to form a printed layer, and then the printed layer is baked to form a patterned semiconductor layer a method of manufacturing, calcination is state, and are due to performing heat of 600 ° C. or higher in a reducing atmosphere, the germanium (Ge) nanoparticles, the dispersion medium in the presence of a surfactant (a ) In which the germanium (Ge) nanoparticle dispersion dispersed with an average particle size of 100 nm or less is not compatible with the surfactant at an arbitrary ratio, and the dispersion medium (A) is at a certain ratio. By adding the compatible liquid (B) to the germanium (Ge) nanoparticle dispersion, the germanium (Ge) nanoparticle is precipitated, and the germanium (Ge) nanoparticle having a process of removing the supernatant dispersion medium (A) is removed. Dispersion medium for particle dispersion Are those obtained through the triggering method method, a manufacturing method of the surfactant is a nonionic surfactant der Ru semiconductor substrate,
(2) A semiconductor substrate on which a coating layer containing germanium (Ge) nanoparticles is printed in a pattern on a substrate to form a printed layer, and then the printed layer is baked to form a patterned semiconductor layer A hydrogen plasma method is used for the firing , and the germanium (Ge) nanoparticles are dispersed in a dispersion medium (A) in the presence of a surfactant with an average particle size of 100 nm or less. The germanium (Ge) nanoparticle dispersion is not compatible with the surfactant in an arbitrary ratio, and the liquid (B) compatible with the dispersion medium (A) in a certain ratio is germanium (Ge). By adding to the nanoparticle dispersion, the germanium (Ge) nanoparticles were precipitated and obtained through a dispersion medium replacement method of the germanium (Ge) nanoparticle dispersion having a process of removing the supernatant dispersion medium (A) The interface Sex agent Ru nonionic surfactants der, a method of manufacturing a semiconductor substrate, characterized in that,
(3) The method for producing a semiconductor substrate according to (1) or (2), wherein the Ge nanoparticles have a particle size of 1 to 100 nm,
(4) The method for producing a semiconductor substrate according to any one of (1) to (3) , wherein at least the surface of the Ge nanoparticles is oxidized,
(5) said substrate, Si wafer, comprising selected from quartz glass, and ceramic substrates, wherein (1) to a method of manufacturing a semiconductor substrate according to any one of (4) and,
(6) The method for producing a semiconductor substrate according to any one of (2) to (4) , wherein the substrate is made of a plastic film having a melting point of 200 ° C. or higher .
Is to provide.

  According to the present invention, on the base material, a coating liquid containing Ge nanoparticles is printed in a pattern to form a printed layer, and then the printed layer is baked to form a patterned semiconductor layer. Compared to the case where a thin film is once formed on the entire substrate and a thin film semiconductor layer with a predetermined pattern is formed using a photoresist, as in the case of manufacturing a semiconductor thin film using amorphous silicon or the like, material costs, number of processes, processing costs, etc. are greatly increased. Thus, a semiconductor substrate having practically sufficient semiconductor characteristics can be manufactured with high productivity and low cost.

  In the method for producing a semiconductor substrate of the present invention, on the substrate, a coating liquid containing Ge nanoparticles is printed in a pattern to form a printed layer, and then the printed layer is baked to form a patterned semiconductor layer. A method of manufacturing a semiconductor substrate to be formed, characterized in that the baking is performed by heating at 600 ° C. or higher in a reducing atmosphere or using a process of generating hydrogen radicals.

  The substrate used in the present invention is not particularly limited as long as it is used for a semiconductor substrate. For example, Si wafer, glass such as quartz glass, inorganic material such as ceramic substrate, film, sheet, Alternatively, various plate-like plastics can be used, but a film form is preferable from the viewpoint of thinning.

Examples of the plastic that can be used as the film substrate include those having a melting point of 200 ° C. or higher in consideration of the heat resistance of the reduction treatment. For example, polyimide, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), Examples thereof include polyphenylene sulfide, polyether ether ketone, polyether sulfone, and liquid crystal polymer.
Moreover, you may form an easily bonding component film on the surface of a base material. Alternatively, easy adhesion treatment by corona treatment, dry UV irradiation treatment, plasma treatment or the like may be performed.

The Ge nanoparticles used in the production method of the present invention are those having an average particle diameter of 1 to 100 nm, such as dispersibility in coating liquid, reduction treatment, easiness of firing, and fine line reproducibility during pattern formation. It is preferable from the viewpoint.
If the average particle size of the Ge nanoparticles is less than 1 nm, synthesis may be difficult. If the average particle size exceeds 100 nm, the dispersion stability of the coating solution is poor, the melting point becomes too high, and sintering becomes difficult. The fine line reproducibility during pattern formation may be inferior.
From the above viewpoint, the average particle diameter of the Ge nanoparticles is more preferably in the range of 1 to 50 nm, and further preferably in the range of 2 to 30 nm.
Further, in order to enhance the dispersion stability of the coating solution, the surface treatment of Ge nanoparticles may be performed, or a dispersant composed of a polymer, an ionic compound, a surfactant or the like may be added.

  Water and / or an organic solvent can be used as a dispersion medium for forming a coating solution containing Ge nanoparticles and dispersing the Ge nanoparticles. Examples of the organic solvent include methanol, ethanol, n-propanol, isopropanol, n-butanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin and other alcohols; toluene, xylene and other aromatic hydrocarbons; acetone, methyl ethyl ketone , Ketones such as methyl isobutyl ketone, cyclohexanone, isophorone; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate; tetrahydrofuran, dioxane, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (Ethyl cellosolve), ethers such as ethylene glycol monobutyl ether (butyl cellosolve), hexane, etc. Aliphatic hydrocarbons, alicyclic hydrocarbons such as cyclohexane, chloroform, dichloroethane, and some halogen-substituted hydrocarbon dichlorobenzene, and the like.

In addition, in the coating liquid, for example, polyester resin, acrylic resin, or urethane is used for the purpose of enhancing adhesion to a substrate, enhancing film forming property, imparting printability, and enhancing dispersibility. Resin or the like is added as a resin binder.
Furthermore, an inorganic binder such as ethyl silicate and a silicate oligomer may be used in order to maintain adhesion or film-forming property with the base material after firing at a high temperature. Moreover, you may add a viscosity modifier, a surface tension modifier, a stabilizer, etc. as needed.

  The coating solution containing the Ge nanoparticles of the present invention preferably has a solid content concentration of 5 to 60% by mass. If the solid content concentration is less than 5% by mass, a sufficient film thickness may not be obtained. If the solid content concentration exceeds 60% by mass, the dispersibility is inferior, and the coating liquid containing Ge nanoparticles on the substrate is printed in a pattern. May be difficult. From the above viewpoint, the solid content concentration in the metal fine particle dispersion is more preferably in the range of 10 to 50% by mass.

The method for printing a coating solution containing Ge nanoparticles on a substrate is not particularly limited, and gravure printing, screen printing, spray coating, spin coating, comma coating, bar coating, knife coating, offset printing, flexographic printing. Methods such as printing, ink jet printing, and dispenser printing can be used. Of these, gravure printing, flexographic printing, and inkjet printing are preferable from the viewpoint that fine patterning can be performed.
In addition, in the present invention, since the coating liquid containing Ge nanoparticles can be directly printed on the base material in a desired pattern, productivity is remarkably improved as compared with the conventional method using a photoresist. Can do.

  The coating liquid containing Ge nanoparticles on the substrate may be dried by a normal method after printing. Specifically, for example, it is heated and dried at a temperature of about 80 to 120 ° C. for about 0.1 to 20 minutes using a normal oven or the like. The film thickness of the printed portion after drying can be controlled by appropriately changing the coating amount and the average particle diameter of Ge nanoparticles according to the application, etc., but is usually in the range of 0.01 to 100 μm, preferably 0. .1 to 50 μm. Drying may be performed by heating in a reducing atmosphere described below, or by baking with hydrogen radicals, or may be performed without heating in air.

In the first method for producing a semiconductor substrate of the present invention, the printed layer is baked at 600 ° C. or higher in a reducing atmosphere.
Before firing in a reducing atmosphere, in order to remove organic substances such as a dispersant contained in the Ge nanoparticle dispersion, heating may be performed in the atmosphere at a temperature of 300 to 500 ° C. for 30 minutes to 2 hours. preferable. By this heat treatment, organic substances are oxidatively decomposed and removed.
In the method of the present invention, the reason why the reducing atmosphere is used is that Ge nanoparticles are easily oxidized because they are fine particles. In particular, the surface is made of insulating germanium oxide, and the Ge nanoparticles are applied in a pattern. This is for reducing and removing the oxide film and the like on the surface because the particles are not electrically connected to each other and sufficient semiconductor characteristics cannot be obtained. Moreover, you may use the oxidation Ge nanoparticle oxidized to the inside of particle | grains in this invention.
As a reduction method for obtaining a reducing atmosphere, a method using a reducing gas such as carbon monoxide, ammonia or hydrogen, a method using a reducing liquid such as glycol, diol or aldehyde, or NaBH ₄ or LiAlH. A method using a reducing agent such as
From the viewpoint of promoting the reduction and firing of Ge nanoparticles, it is important that the heating temperature is 600 ° C. or higher. The upper limit of the temperature depends on the heat resistance of the substrate, and the substrate must be deformed or melted. However, the temperature is generally about 1000 ° C. from the viewpoint of safety when using a reducing agent.
In addition, when performing this heat processing at 600 degreeC or more, since heat resistance is requested | required also for a base material, it is preferable to select a base material from glass, such as Si wafer and quartz glass, and a ceramic substrate.

In the second method for producing a semiconductor substrate of the present invention, the printing layer is fired by a process of generating hydrogen radicals.
When hydrogen radicals are used for firing the printed layer, the surface oxide film of the Ge nanoparticles is reduced and the organic components of the coating solution are removed while activating the Ge nanoparticles and firing as a thin semiconductor layer It is. If this process for generating hydrogen radicals is used, Ge nanoparticles can be fired at a relatively low temperature, so that a heat-resistant plastic film such as polyimide, PEN, and PET can be used as a base material. .
An example of a process for generating hydrogen radicals is a hydrogen plasma method.

  In the hydrogen plasma method, for example, a substrate is placed in a parallel plate electrode type plasma apparatus. At this time, it is better to place the substrate on the anode (anode) side so as not to be damaged by plasma ions, etc. If the substrate can be heated, the effect of the separation will be enhanced by heat. The When heat is applied, the substrate temperature can be set to 900 ° C. or higher if the base material is relatively heat resistant, such as quartz or Si wafer. It is effective to use a product made of the same. Also, when using a substrate such as a plastic film, it is more convenient to use a metal such as stainless steel for the chamber of the plasma apparatus because the substrate temperature cannot be so high.

  When hydrogen gas is introduced and high frequency power is applied between the parallel plate electrodes, plasma is generated. In the plasma, highly active neutral hydrogen radicals are generated together with hydrogen ions and electrons. The generated hydrogen radicals and ions reach the surface of the base material coated with Ge nanoparticles, and the Ge nanoparticles are fired while removing the oxide film on the surface of the Ge nanoparticles. At the same time, organic substances such as a dispersant are decomposed by hydrogen radicals. The water and carbon gasified by reaction are exhausted by a pump.

  The Ge nanoparticles used in the present invention are obtained by dispersing the Ge nanoparticle dispersion dispersed in the dispersion medium (A) in the presence of a surfactant with an average particle size of 100 nm or less in any proportion with the surfactant. A liquid (B) that is not compatible and is compatible with the dispersion medium (A) in a certain ratio is added to the Ge nanoparticle dispersion to precipitate Ge nanoparticles, and the supernatant dispersion medium (A) is added to the dispersion medium (A). It is preferable to use what was obtained through the dispersion medium substitution method of the Ge nanoparticle dispersion which has a removal process.

The Ge nanoparticles used in the present invention are used by replacing the dispersion medium in the Ge nanoparticle dispersion with a dispersion medium suitable for the coating liquid in order to prepare a coating liquid.
That is, Ge nanoparticles are synthesized by a physical synthesis method such as a spark erosion method, a gas evaporation method, or a vacuum deposition method, but are dispersed in an average particle size of 100 nm or less in the dispersion medium (A) used at the time of synthesis. The Ge nanoparticle dispersion is added to the Ge nanoparticle dispersion with a liquid (B) that is incompatible with the surfactant at an arbitrary ratio and compatible with the dispersion medium (A) at a certain ratio. It is preferable to use what was obtained through the dispersion medium substitution method of Ge nanoparticle dispersion which has a process which sediments Ge nanoparticle and removes the supernatant dispersion medium (A).
Here, the vacuum vapor deposition method is a method described below for producing a simple substance of Ge, a Ge alloy or a Ge compound by contacting the dispersion medium (A) in which the surfactant is dissolved. The production method of this Ge nanoparticle dispersion may be abbreviated as “vacuum deposition method”.

  And finally, it is preferable that Ge nanoparticle dispersion liquid is further disperse | distributed in the dispersion medium (C) mentioned later.

  The average particle diameter of the Ge nanoparticles is not particularly limited as long as it is 100 nm or less, but even when the average particle diameter is 10 nm or less, the dispersion medium can be stably replaced. Further, Ge particles obtained using the dispersion medium replacement method of the present invention can be used. The average particle diameter of Ge nanoparticles in the nanoparticle dispersion is usually 1 nm to 100 nm, preferably 1 nm to 50 nm, more preferably 1 nm to 20 nm, particularly preferably 1 nm to 15 nm, and further preferably 1 nm to 10 nm. The smaller the average particle diameter, the more preferable because the stable dispersion medium replacement of the present invention is possible.

  The shape of the Ge nanoparticles is not particularly limited, and may be any of spherical, rod-like, fiber-like, plate-like, and amorphous, but is preferably amorphous in view of dispersibility. The dispersion medium replacement method of the present invention is preferably applied to a dispersion of amorphous Ge nanoparticles. Therefore, the amorphous nanoparticle dispersion is particularly preferable as the Ge nanoparticle dispersion prepared by the dispersion medium replacement method of the present invention.

<Dispersion medium (A)>
The Ge nanoparticle dispersion which is the target of the dispersion medium replacement method of the present invention is one in which Ge nanoparticles are dispersed in the dispersion medium (A). That is, the dispersion medium (A) is a target for substitution. As long as the dispersion medium (A) can disperse Ge nanoparticles, the chemical structure, boiling point, vapor pressure and the like are not particularly limited. Since the dispersion medium replacement method of the present invention is also an alternative to the vacuum distillation of the dispersion medium, it is preferable that the dispersion medium (A) is a high boiling point solvent from the viewpoint of the effects of the present invention.

The boiling point at 1 atm of the dispersion medium (A) is not particularly limited, but is preferably 40 ° C. or higher, more preferably 100 ° C. or higher, and particularly preferably 200 ° C. or higher.
Also, the vapor pressure of the dispersion medium (A) is not particularly limited, but the vapor pressure at 25 ° C. is preferably 10 ⁻³ Pa or less, more preferably 10 ⁻⁴ Pa or less, more preferably 10 ^−5. It is particularly preferred that it is Pa or less. In particular, when a Ge nanoparticle dispersion is prepared by a vacuum vapor deposition method to be described later, the dispersion medium (A) is limited to a high boiling point and a low vapor pressure. When applied to the Ge nanoparticle dispersion obtained by the vacuum evaporation method, it is particularly preferable that the dispersion medium (A) has a high boiling point and a low vapor pressure as described above.

In the present invention, the “germanium gas” is dispersed in the low vapor pressure liquid by bringing the gas into contact with the low vapor pressure liquid. The “low vapor pressure liquid” refers to a liquid that has a low vapor pressure at the dispersion temperature and does not substantially volatilize at 10 ⁻³ Pa. If the vapor pressure is not low, it may evaporate and interact with the “germanium gas” to adversely affect dispersibility.
The vapor pressure is preferably 10 ⁻¹⁰ Pa to ^{10 −5} Pa at 25 ° C., particularly preferably 10 ⁻⁸ Pa to 10 ⁻⁶ Pa at 25 ° C. The boiling point at 1 atm of such a low vapor pressure liquid is not particularly limited, but is preferably 180 ° C. or higher, more preferably 200 ° C. or higher, particularly preferably 220 ° C. or higher, and further preferably 240 ° C. or higher for the same reason as described above.

Specifically, for example,
It may have a substituent such as alkylbenzenes such as toluene, xylene and ethylbenzene, 1-methylnaphthalene, sabotalene, cadalene, and alkylnaphthalenes such as “naphthalene having an alkyl group having 2 to 20 carbon atoms”. Aromatic hydrocarbons ";
Ketones such as cyclohexanone, methylisoptyl ketone, isophorone;
Alkylene such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, dipropylene glycol monopropyl ether acetate Glycol monoalkyl ether acetates; ethers such as alkyl diphenyl ether, polyphenyl ether, polyalkylphenyl ether;
Lactones such as γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone, and δ-caprolactone;
Silicone compounds such as silicones and polyalkylsiloxanes;
Fluorocarbons;
Polyhydric alcohols;
And the like are preferable. These are used alone or in a mixture of two or more.

  In particular, when the dispersion medium replacement method of the present invention is applied to a Ge nanoparticle dispersion obtained by a vacuum vapor deposition method, alkyl naphthalene, alkyl diphenyl ether, polyphenyl ether, polyphenyl ether, and the like are particularly preferable as the dispersion medium (A). Examples include alkylphenyl ether, silicone pond, polyalkylsiloxane, and fluorocarbon oil. Here, the alkyl group is not particularly limited, but preferably has 4 to 24 carbon atoms, more preferably has 8 to 22 carbon atoms, and particularly preferably has 12 to 20 carbon atoms. Commercially available diffusion pump oil is also preferred.

  When the dispersion medium (A) is an aliphatic and / or aromatic hydrocarbon, the total number of carbon atoms is preferably 14 or more, more preferably 20 or more, and 25 or more. It is particularly preferred that These are used alone or in combination of two or more.

<Surfactant>
The Ge nanoparticle dispersion which is the target of the dispersion medium replacement method of the present invention is one in which Ge nanoparticles are dispersed in the dispersion medium (A) in the presence of a surfactant. Here, the “surfactant” is not particularly limited as long as Ge nanoparticles can be well dispersed in the dispersion medium (A), but further, the requirements described later in relation to the dispersion medium (A). It is necessary to be a “surfactant” such that a suitable liquid (B) satisfying the above condition exists.

  Specifically, carboxylate-based, sulfonate-based, sulfate ester-based, phosphate ester-based and the like anionic surfactants; cationic surfactants; amphoteric surfactants; ethers, ester ethers , Ester-based, nitrogen-containing, etc. nonionic surfactants; fluorine-based surfactants; reactive surfactants, and the like. Among these, there is a combination of “dispersion medium (A), surfactant and liquid (B)” that satisfies the requirements of the present invention when the nonionic surfactant gives good dispersibility and the dispersion medium is replaced. It is preferable in that it is easy to do.

  Of these, nitrogen-containing nonionic surfactants and ester-based nonionic surfactants are more preferable for the same reason as described above. The nonionic surfactant such as nitrogen-containing system is not particularly limited as long as it is a surfactant having an amine or imide group, but having a polyalkenyl group is highly lipophilic, This is particularly preferable from the viewpoint of high solubility in a low vapor pressure liquid which is preferable as the dispersion medium (A). The ester-based surfactant is not particularly limited as long as it is a compound having an ester group and having a surfactant activity. However, the ester surfactant is an ester of a polyhydric alcohol and a carboxylic acid. ) Is particularly preferred because of its high solubility in a low vapor pressure liquid, low reactivity and high stability. Moreover, it is especially preferable also from the point that "the liquid (B) which satisfy | filled the requirement of compatibility" mentioned later exists.

  The polyalkenyl group preferably has 5 to 30 carbon atoms, more preferably 10 to 25 carbon atoms, and particularly preferably 12 to 22 carbon atoms.

  As the carboxylic acid, a carboxylic acid having 8 to 28 carbon atoms is preferable, a carboxylic acid having 12 to 24 carbon atoms is more preferable, and a carboxylic acid having 15 to 22 carbon atoms is particularly preferable.

  Although it does not specifically limit as said polyhydric alcohol, Specifically, saccharides, such as ethylene glycol, polyethyleneglycol; propylene glycol, polypropylene glycol; glycerin, polyglycerin; pentaerythritol, trimethylolpropane; sucrose, glucose, etc. Preferred examples include sugar alcohols such as sorbit (reduced saccharides); cyclized products resulting from dehydration of sugar alcohols such as sorbitan. Among these, as the polyhydric alcohol, sugar alcohol or a cyclized product obtained by dehydration of the sugar alcohol is particularly preferable because it is excellent in dispersibility, dispersion stability, and high concentration dispersibility.

  The hydroxyl group of the polyhydric alcohol may be substantially all esterified with an acid or may not be all esterified and a hydroxyl group may remain, but those having one or more hydroxyl groups remaining are preferred.

  Specific examples of ester surfactants include (poly) ethylene glycol fatty acid esters such as ethylene glycol monofatty acid ester, ethylene glycol difatty acid ester, polyethylene glycol monofatty acid ester, and polyethylene glycol difatty acid ester; propylene (Poly) propylene glycol fatty acid esters such as glycol monofatty acid ester, propylene glycol difatty acid ester, polypropylene glycol monofatty acid ester, polypropylene glycol difatty acid ester; glycerin monofatty acid ester, glycerin difatty acid ester, polyglycerin fatty acid ester ( Poly) glycerin fatty acid esters; sugar fatty acid esters such as sucrose fatty acid ester and glucose fatty acid ester; sorby Sugar alcohol fatty acid esters such as fatty acid esters of glucose (glucose alcohol of glucose); fatty acid esters of “cyclized products of dehydration of sugar alcohol” such as sorbitan (cyclized product by dehydration of sorbit); polyoxyethylene glycerin fatty acid ester Polyoxyethylene fatty acid esters such as polyoxyethylene castor oil and polyoxyethylene hydrogenated castor oil; polyoxyethylene sugar alcohol fatty acid esters such as polyoxyethylene sorbite fatty acid ester; Oxyethylene chain-containing “fatty acid esters of cyclized product by dehydration of sugar alcohol” and the like are preferable. These are used alone or in combination of two or more.

The concentration of the surfactant in the Ge nanoparticle dispersion that is the subject of the dispersion medium replacement method of the present invention is not particularly limited and can be adjusted as appropriate. 0.3-50 mass parts of an agent is preferable, 1-20 mass parts is more preferable, and 3-10 mass parts is especially preferable.
If the amount of the surfactant is too small, the dispersibility may be insufficient and may not be dispersed well. On the other hand, if the amount is too large, the viscosity of the dispersion becomes too high. May become difficult.

  The concentration of Ge nanoparticles in the Ge nanoparticle dispersion that is the target of the dispersion medium replacement method of the present invention is not particularly limited, but is 1 to 90 parts by mass of Ge nanoparticles with respect to 100 parts by mass of the Ge nanoparticle dispersion. Is preferable, 10-80 mass parts is more preferable, and 20-70 mass parts is especially preferable. By using the present invention, it is possible to replace a dispersion medium of a high concentration Ge nanoparticle dispersion.

<Liquid (B)>
The dispersion medium replacement method of the present invention is a dispersion medium replacement method for a Ge nanoparticle dispersion in which Ge nanoparticles are dispersed in a dispersion medium (A) in the presence of a surfactant, Is added to the Ge nanoparticle dispersion by adding a liquid (B) that is incompatible with an arbitrary ratio and compatible with the dispersion medium (A) to a certain ratio, thereby precipitating the Ge nanoparticles. It has a process of removing the supernatant dispersion medium (A).

That is, in the dispersion medium replacement method of the present invention, by adding the liquid (B) to the Ge nanoparticle dispersion, the Ge nanoparticles are settled, and the supernatant “dispersion medium (A) and liquid (B )) "Alone" is removed by decantation or the like. Here, the requirements that the liquid (B) satisfies are as follows.
(1) It is incompatible with the surfactant in the Ge nanoparticle dispersion to be dispersed medium at an arbitrary ratio.
(2) It is compatible with the dispersion medium (A) in the Ge nanoparticle dispersion that is the target of the dispersion medium substitution at a certain ratio.

When the liquid (B) satisfying the requirements (1) and (2) is used, the dispersion medium (A) can be suitably replaced with the dispersion medium (C) described later, and the dispersion is maintained before and after the dispersion medium replacement. It is possible to provide a dispersion medium replacement method having excellent properties.
Regarding requirement (1), it is essential that the liquid (B) is incompatible with the surfactant at an arbitrary ratio. If the compatibility between the liquid (B) and the surfactant in the Ge nanoparticle dispersion is too high, that is, if the liquid (B) and the surfactant are compatible at an arbitrary ratio, the liquid (B) When Ge is added to the Ge nanoparticle dispersion, Ge nanoparticles dispersed therein may not settle.

  The boiling point and vapor pressure of the liquid (B) are not particularly limited, but are preferably lower boiling point and higher vapor pressure than the dispersion medium (A). After adding the liquid (B), the precipitated Ge nanoparticles are left in the container, and the mixed liquid of the dispersion medium (A) and the liquid (B) is removed by decantation, and the liquid (B) is added again and decantation is performed. Although it is preferable to repeat, the liquid (B) remaining in the last decantation is easily distilled off under reduced pressure without heating, if necessary.

  The boiling point of the liquid (B) at 1 atm is preferably 180 ° C. or lower, more preferably 150 ° C. or lower, and particularly preferably 100 ° C. or lower.

Specifically, the liquid (B) is mainly determined depending on the compatibility relationship with the surfactant and the dispersion medium (A), and is not particularly limited.
alcohol systems such as n-propanol, iso-propanol (hereinafter abbreviated as “IPA”), butanol, pentanol, hexanol;
Ketones such as acetone, ethyl methyl ketone (hereinafter abbreviated as “MEK”), cyclohexanone, methyl isoptyl ketone;
Ethers such as ethyl methyl ether, diethyl ether, furan, tetrahydrofuran;
Ester systems such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate;
Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monoethyl ether ← teracetate, dipropylene Alkylene glycol monoalkyl ether acetates such as glycol monopropyl ether acetate, diethylene glycol monobutyl ether acetate (hereinafter abbreviated as “BDGAc”), dipropylene glycol monobutyl ether acetate;
Lactone systems such as γ-ptyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone, δ-caprolactone;
Halogenated hydrocarbon systems such as chloroform, dichloroethane, 1,1-dipromoethane, 1,1,1-trichloroethane;
Etc. These are used alone or in a mixture of two or more.

<Dispersion medium (C)>
In the present invention, after the above-mentioned “process of adding the liquid (B) to the Ge nanoparticle dispersion to settle the Ge nanoparticles and removing the supernatant dispersion medium (A)”, the dispersion medium (C It is preferable for the purpose of the present invention to obtain a “Ge nanoparticle dispersion liquid” by adding a process of adding (A). The “Ge nanoparticle dispersion liquid” is a dispersion medium (C) in which germanium (Ge) simple substance, germanium (Ge) alloy or germanium (Ge) compound Ge nanoparticles are dispersed. A small amount of dispersion medium (A) or liquid (B) may remain in the “Ge nanoparticle dispersion”. In addition, the thing before a dispersion medium substitution is called "Ge nanoparticle dispersion", and the thing after dispersion medium substitution is called "Ge nanoparticle dispersion liquid."

  The dispersion medium (C) can be appropriately selected from those suitable for various uses of the Ge nanoparticle dispersion. Therefore, as the dispersion medium (C), general-purpose solvents or dispersions generally used for inks, paints, catalyst materials, medical use, etc. as well as solvents or dispersion media for production of ICs, semiconductors, conductive films, filters, etc. A medium.

  The dispersion medium (C) is preferably compatible with the surfactant at least in a certain ratio, but is compatible with an arbitrary ratio, so that the dispersibility and dispersion stability of the Ge nanoparticle dispersion can be improved. Are particularly preferred from the standpoints of properties, high-concentration dispersibility, and dispersion maintenance.

  The dispersion medium (C) is preferably one that makes the liquid (B) compatible at a certain ratio. If the liquid (B) is not compatible even with a small amount, the liquid (B) may remain even by decantation, so that the Ge nanoparticle dispersion may be separated into two layers.

  The dispersion medium (C) can be selected depending on the application. Specifically, for example, hydrocarbon solvents such as toluene, xylene, n-hexane and tetradecane; ester solvents such as ethyl acetate and butyl acetate; propylene Glycol solvents such as glycol monoethyl ether, propylene glycol monoethyl ether acetate, dipropylene glycol monoethyl ether, diethylene glycol monoptyl ether acetate; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone. However, it is not limited to them. These may be used alone or in combination of two or more.

<Ge nanoparticle dispersion>
The method for preparing the Ge nanoparticle dispersion used in the present invention is not particularly limited, and the dispersion medium (A) can be replaced with any Ge nanoparticle dispersion prepared by any method. It is preferably applied to Ge nanoparticle dispersions prepared by the method.
That is, it is preferably used for a Ge nanoparticle dispersion produced by bringing a gas of a metal simple substance, a metal alloy or a metal compound into contact with the dispersion medium (A) in which the surfactant is dissolved.

The liquid (B) is added to the dispersion medium (A) of the Ge nanoparticle dispersion prepared by the vacuum deposition method to precipitate the Ge nanoparticles, and then the dispersion medium (C) is added to the Ge nanoparticle dispersion. It is preferable to replace the dispersion medium (A) of the nanoparticle dispersion with the dispersion medium (C). The dispersion medium (A) used in the vacuum deposition method is limited to those having a high boiling point and a low vapor pressure, and the dispersion medium is not suitable for various uses as it is. The method becomes more effective.
Further, in the relationship between the surfactant suitably used in the vacuum deposition method and the liquid (B) in the present invention, there are actually various combinations that satisfy the requirements (1) and (2). In order to replace the Ge nanoparticle dispersion with a dispersion medium, the Ge nanoparticle dispersion is preferably applied to a Ge nanoparticle dispersion prepared by a vacuum deposition method.

  Hereinafter, “Ge nanoparticle dispersion prepared by vacuum deposition method” to which the dispersion medium replacement method of the present invention can be suitably applied will be described.

  The “Ge simple substance, Ge alloy or Ge compound” dispersed by the vacuum deposition method (hereinafter may be abbreviated as “Ge etc.”) is not particularly limited as long as it becomes a gas by heating or the like. The method for making the gas is not particularly limited, and is performed by a known heating method. The heating temperature is not particularly limited, and varies depending on the type of Ge or the like, but is preferably 400 to 2000 ° C, more preferably 600 to 1700 ° C, particularly preferably 800 to 1600 ° C, and further preferably 1000 to 1400 ° C.

  In the vacuum deposition method, a Ge nanoparticle dispersion is obtained by bringing a gas such as Ge into contact with the dispersion medium (A). At that time, an inert gas such as helium, argon, nitrogen, etc .; dispersion medium, dispersion aid, etc. This does not exclude the coexistence of organic gases, etc., but there is no need for them to coexist because of the working principle of the vacuum deposition method in which molecules are brought into contact with a liquid to create a dispersed state at the liquid phase interface.

The pressure when forming the dispersion by bringing the gas of “Ge or Ge compound” into contact with the dispersion medium (A) described later is not particularly limited, but is preferably 10 ⁻¹ Pa or less. It is particularly preferably 10 ⁻² Pa or less. Moreover, it is preferable that it is 10 ^<-4 > Pa or more, and it is especially preferable that it is 10 ^<-3 > Pa or more. If the pressure is too high, that is, the degree of vacuum is poor, problems such as the need to increase the heating temperature and the influence of the gas intervening there and the quality of the Ge nanoparticles may occur. If the pressure is too small, that is, the degree of vacuum is unnecessarily high, the dispersion medium (A) may volatilize, productivity may drop, or the vacuum pump may be overloaded.

If the dispersion medium (A) in the vacuum deposition method is not low vapor pressure, it may evaporate and interact with the “Ge gas or Ge compound gas” to adversely affect the dispersibility.
In the present invention, the vapor pressure of the dispersion medium (A) is preferably 10 ⁻³ Pa or less at 25 ° C., but more preferably 10 ⁻¹⁰ Pa to ^{10 −5} Pa at 25 ° C. in the vacuum deposition method. Particularly preferably, it is 10 ⁻⁸ Pa to 10 ⁻⁶ Pa at 25 ° C. The boiling point of the dispersion medium (A) at 1 atm is not particularly limited, but for the same reason as above, it is preferably 180 ° C. or higher, more preferably 200 ° C. or higher, particularly preferably 220 ° C. or higher, and further 240 ° C. or higher. preferable.

  In the vacuum vapor deposition method, when the gas is brought into contact with the dispersion medium (A), the gas becomes solid Ge nanoparticles and is dispersed in the dispersion medium (A). It is preferable that the ester surfactant is dissolved in Dispersion particles having a small average particle diameter can be formed by dissolving an ester surfactant, and a dispersion having excellent dispersibility, dispersion stability, high concentration dispersibility, etc. even with a small particle diameter. Can be obtained.

  Although the density | concentration of Ge nanoparticle in Ge nanoparticle dispersion manufactured by the vacuum evaporation method does not have limitation in particular, 1-90 mass parts is preferable with respect to 100 mass parts of Ge nanoparticle dispersion, 10-80 masses Part is more preferable, and 20 to 70 parts by mass are particularly preferable. If the vacuum deposition method is used, a high concentration Ge nanoparticle dispersion can be obtained, and “maintenance of high concentration dispersibility”, which is a feature of the dispersion medium replacement method of the present invention, can be suitably applied.

  The vacuum deposition method will be described in more detail using the manufacturing apparatus shown in FIG. 1 as an example. However, FIG. 1 is an example of a specific apparatus, and the present invention is not limited to this.

In FIG. 1, the chamber (1) has a drum shape rotating around the fixed shaft (2), and the inside of the chamber (1) is evacuated to high vacuum through the fixed shaft (2).
A dispersion medium (A) (3) in which a surfactant is dissolved is placed in the chamber (1), and the surfactant is applied to the inner wall of the chamber (1) by the rotation of the drum-shaped chamber (1). A film (4) of the dissolved dispersion medium (A) (3) is formed. Inside the chamber (1), a container (6) for containing Ge or the like (5) is fixed. Ge or the like (5) is heated to a predetermined temperature, for example, by passing a current through a resistance wire, and is released into the chamber (1) as a gas.

  The entire outer wall of the chamber (1) is cooled by the water flow (8). The atoms (9) released into the vacuum from the heated Ge or the like (5) are taken in from the surface of the film (4) of the dispersion medium (A) (3) in which the surfactant is dissolved. Ge nanoparticles (10) are formed. Next, the dispersion medium (A) (3) in which Ge nanoparticles (10) such as Ge are dispersed is dispersed in the dispersion medium (A) (3) at the bottom of the chamber (1) as the chamber (1) rotates. At the same time, a new “dispersion medium (A) (3) membrane (4)” is fed to the top of the chamber (1).

  By continuing this process, the dispersion medium (A) (3) at the bottom of the chamber (1) becomes a dispersion in which Ge nanoparticles such as Ge (5) are dispersed at a high concentration.

  Although the action and principle of the vacuum deposition method are not clear, a gas such as Ge is not directly aggregated in the gas phase but is directly taken into the dispersion medium (A) whose surface is covered with a surfactant, and the dispersion medium ( When aggregation occurs in A) and it has a certain average particle diameter, it is considered that the aggregated particles are surrounded by the surfactant and stabilized as Ge nanoparticles.

<Ge nanoparticle dispersion>
By using the dispersion medium substitution method of the Ge nanoparticle dispersion of the present invention, a Ge nanoparticle dispersion liquid in which Ge nanoparticles such as Ge are dispersed in the dispersion medium (C) is obtained. According to the dispersion medium replacement method of the present invention, the average particle diameter of the Ge nanoparticles in the Ge nanoparticle dispersion after the dispersion medium replacement is the average particle diameter of the Ge nanoparticles in the Ge particle dispersion before the dispersion medium replacement. It can be 1.2 times or less with respect to the diameter. In another aspect of the present invention, the average particle diameter of the Ge nanoparticles in the Ge nanoparticle dispersion after the dispersion medium substitution is the average particle diameter of the Ge nanoparticles in the Ge nanoparticle dispersion before the dispersion medium substitution. It is a Ge nanoparticle dispersion liquid that is 1.2 times or less of that. Furthermore, it is possible to make it 1.1 times or less. The dispersion medium replacement method for the Ge nanoparticle dispersion of the present invention is excellent in dispersion maintenance.

  Here, the average particle diameter of the Ge nanoparticles is obtained by randomly selecting 100 Ge nanoparticles using a transmission electron micrograph of 100,000 times, measuring the diameter, and taking the average. It was.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples unless it exceeds the gist.

Production Example 1
<Preparation of Ge nanoparticle dispersion>
Using 380 g of Lion diffusion pump oil (A) (manufactured by Lion Corporation) as a dispersion medium (A), 20 g of polyisobutenyl succinic acid tetraamine imide (manufactured by Sanyo Chemical Industries) was added and stirred. Lion diffusion pump oil (A) is an alkylnaphthalene having an alkyl group having 12 to 16 carbon atoms.

A dispersion was produced using the apparatus shown in FIG. In the vessel (6), germanium (Ge) particles were put, and the dispersion medium (A) was put in the rotating drum type chamber (1). By suctioning with a vacuum pump, the pressure in the chamber (1) was allowed to reach 10 ⁻³ Pa. Next, the chamber (1) was rotated while being cooled with a water flow (7), and heated until germanium (Ge) was dissolved and evaporated.

  The germanium (Ge) particles are dissolved, and the gas of germanium (Ge) is deposited on the surface of the dispersion medium (A) in which the surfactant is dissolved, and is taken into the surfactant, whereby germanium (Ge) Ge. A Ge nanoparticle dispersion in which nanoparticles were dispersed was formed. By observation with a transmission electron microscope, it was confirmed that Ge nanoparticles having an average particle diameter of about 2 nm to 15 nm were dispersed without aggregation.

<Dispersion medium replacement method of germanium (Ge) Ge nanoparticle dispersion>
To 50 g of the Ge nanoparticle dispersion prepared above, methyl ethyl ketone (MEK) was added as a liquid (B) to prepare a total of 500 mL. After stirring, the mixture was allowed to stand at 25 ° C. for 1 day. The nanoparticles settled. The precipitated Ge nanoparticles were completely phase separated from MEK in which alkylnaphthalene as the dispersion medium (A) was dissolved.

  The supernatant “MEK in which the dispersion medium (A) was dissolved” was discarded by decantation, MEK was added again, and the mixture was allowed to stand for 10 hours. The dispersion medium (A) was almost removed by decanting again.

  MEK was distilled off under reduced pressure at 30 ° C. until about 5 mL. Next, toluene was added as a dispersion medium (B) to Ge nanoparticles precipitated in a small amount of MEK. The Ge nanoparticles re-dispersed well in toluene. As a result, alkylnaphthalene [dispersion medium (A)] can be replaced with general-purpose dispersion medium toluene [dispersion medium (B)]. Finally, Ge nanoparticles in which Ge nanoparticles are dispersed in toluene A dispersion was prepared.

By observation with a transmission electron microscope, a stable Ge nanoparticle dispersion liquid was obtained without changing the average particle diameter before and after the dispersion medium substitution (average particle diameter is 1.2 times or less). It was confirmed. That is, it was confirmed that Ge nanoparticles having an average particle diameter of about 2 nm to 18 nm were dispersed without aggregation even after the dispersion medium substitution.
The average particle diameter of the Ge nanoparticles hardly changed before and after the dispersion medium substitution, and it was confirmed by observation with a transmission electron microscope that the particles were dispersed without being aggregated even when the dispersion medium was substituted.

<Preparation of coating solution containing Ge nanoparticles>
A coating liquid having a solid content of 22% by mass was prepared using the Ge nanoparticle dispersion medium substitute obtained above.
Using the coating solution, a semiconductor substrate was produced by printing in a pattern on the substrate, and the semiconductor performance was evaluated.

Evaluation Method The semiconductor substrates obtained in each Example and Comparative Example were evaluated based on mobility and carrier density. The evaluation method is as follows.
(Measurement method of carrier density and measurement method of semiconductor mobility)
In accordance with the van der Pauw method described in the book “Semiconductor Evaluation Technology” (published by Takashi Katoda, Sangyo Tosho Co., Ltd.), p. A sample piece having an electrode formed thereon was prepared and used for measurement.

Example 1
The Ge nanoparticle-containing coating solution was formed into a pattern on a 0.188 mm thick PET substrate (Toray Co., Ltd. Lumirror U34) by inkjet printing (FUJIFILM Dimatix DMP-2831), and then hydrogenated. Reduction by plasma treatment gave a semiconductor substrate.
The hydrogen plasma treatment uses “PED-350 Special Type” manufactured by Canon Anelva Engineering Co., Ltd. as an apparatus, and a 6-inch Si wafer as a transfer substrate, and a 5 cm × 2 cm size PET base material is polyimide on it. The adhesive was fixed with an adhesive tape (No. 360UL manufactured by Nitto Denko Corporation). The pressure in the chamber is 10 Pa, the gas used is a mixed gas of argon / hydrogen = 96/4 (volume ratio), the flow rate is 100 ml / min, the high-frequency power is 500 W, and the plasma treatment time is 15 minutes (5 minutes irradiation) This was repeated three times as it was left for 10 minutes.
About the said semiconductor, when the film thickness was measured with the stylus type surface shape measuring device (Dektak6M by ULVAC, Inc.), it was 0.7 micrometer. In addition, Mitsubishi Chemical Co. The surface resistivity was measured using Loresta Gp (MCP-T610) manufactured according to JIS K7194. The surface resistance was 3 × 10 ⁺⁵ Ω / □. Moreover, when the mobility was measured by the Van der Pauw method, it was about 5 cm ² / Vs. The carrier density was about 10 ¹⁷ / cm ³ .

Example 2
After the Ge nanoparticle-containing coating solution was formed into a pattern on a 0.75 mm thick quartz substrate (Asahi Glass Co., Ltd., synthetic quartz AQ) by ink-jet printing (FUJIFILM Digitix DMP-2831), Heat treatment was performed at 350 ° C. for 60 minutes in the air. Then, it reduced at 650 degreeC by the reducing atmosphere using hydrogen gas, and obtained the semiconductor base material.
In the reduction, the temperature was raised at 10 ° C./min, held at 650 ° C. for 30 minutes, and then air-cooled. As a reducing gas, a mixed gas of argon / hydrogen = 96/4 (volume ratio) was used.
About the said semiconductor, when the film thickness was measured with the stylus type surface shape measuring device (Dektak6M by ULVAC, Inc.), it was 1.4 micrometers. In addition, Mitsubishi Chemical Co. The surface resistivity was measured using Loresta Gp (MCP-T610) manufactured according to JIS K7194. The surface resistance was 4 × 10 ⁺⁴ Ω / □. Moreover, when the mobility was measured by the van der Pauw method, it was about 9 cm ² / Vs. The carrier density was about 10 ¹⁶ / cm ³ .

Example 3
The coating liquid is printed on a 0.075 mm-thick polyimide film (trade name: Kapton 300H, manufactured by Toray DuPont) with a simple gravure printing machine (GP-2, Kurashiki Spinning Co., Ltd.) and 350 in the atmosphere. Heat treatment was performed at 60 ° C. for 60 minutes. Then, it reduced by hydrogen plasma processing and obtained the semiconductor substrate.
As in Example 1, the hydrogen plasma treatment uses “PED-350 special type” manufactured by Canon Anelva Engineering Co., Ltd. as an apparatus, and a 6-inch Si wafer as a transfer substrate, and 5 cm × 2 cm thereon. The size PET substrate was adhered and fixed with a polyimide adhesive tape (Nitto Denko No. 360UL). The pressure in the chamber was set to 10 Pa, the gas used was a mixed gas of argon / hydrogen = 96/4 (volume ratio), the flow rate was 100 ml / min, the high-frequency power was 500 W, and the plasma treatment time was 15 minutes. .
About the said semiconductor, when the film thickness was measured with the stylus type surface shape measuring device (Dektak6M by ULVAC, Inc.), it was 0.8 micrometer. In addition, Mitsubishi Chemical Co. The surface resistivity was measured using Loresta Gp (MCP-T610) manufactured according to JIS K7194. The surface resistance was 8 × 10 ⁺⁴ Ω / □. Moreover, when the mobility was measured by the van der Pauw method, it was about 8 cm ² / Vs. The carrier density was about 10 ¹⁶ / cm ³ .

  The present invention is a method for producing a semiconductor substrate with high practicality that a thin film semiconductor using germanium (Ge) nanoparticles can be produced with high productivity and at low cost. A TFT semiconductor for a display such as a liquid crystal, a solar cell, It can be used effectively for sensors.

It is a schematic sectional drawing of the apparatus used for an example of the manufacturing method of Ge nanoparticle used for the manufacturing method of the semiconductor base material of this invention.

Explanation of symbols

1 Chamber 2 Fixed shaft 3 Dispersing medium in which surfactant is dissolved (A)
4 Dispersion medium (A) film in which surfactant is dissolved 5 Metal etc. 6 Container 7 Water flow 8 Rotating direction 9 Atom 10 Ge nanoparticle

Claims (7)

  A method for producing a semiconductor substrate, comprising: printing a coating solution containing germanium (Ge) nanoparticles in a pattern on a substrate to form a printed layer; and firing the printed layer to form a patterned semiconductor layer. The firing is by heating at 600 ° C. or higher in a reducing atmosphere, and the germanium (Ge) nanoparticles are dispersed in the dispersion medium (A) in the presence of a surfactant. A liquid in which a germanium (Ge) nanoparticle dispersion dispersed with an average particle size of 100 nm or less is incompatible with the surfactant at an arbitrary ratio and compatible with the dispersion medium (A) at a certain ratio. (B) is added to the germanium (Ge) nanoparticle dispersion to settle the germanium (Ge) nanoparticles and remove the supernatant dispersion medium (A). Dispersion medium replacement method Are those obtained through the method of manufacturing the semiconductor substrate, wherein said surfactant is a nonionic surfactant.   A method for producing a semiconductor substrate, comprising: printing a coating solution containing germanium (Ge) nanoparticles in a pattern on a substrate to form a printed layer; and firing the printed layer to form a patterned semiconductor layer. In the firing, a hydrogen plasma method is used, and the germanium (Ge) nanoparticles are dispersed in a dispersion medium (A) in the presence of a surfactant with an average particle diameter of 100 nm or less ( A liquid (B) that is incompatible with the surfactant in any proportion with the Ge) nanoparticle dispersion and is compatible with the dispersion medium (A) in a certain proportion is dispersed in germanium (Ge) nanoparticles. It is obtained through a dispersion medium replacement method for a germanium (Ge) nanoparticle dispersion having a process of sedimenting the germanium (Ge) nanoparticles by adding to the body and removing the supernatant dispersion medium (A). , The surfactant A non-ionic surfactant, a method of manufacturing a semiconductor substrate, characterized in that.   The manufacturing method of the semiconductor substrate of Claim 1 or 2 whose particle size of the said germanium (Ge) nanoparticle is 1-100 nm.   The method for producing a semiconductor substrate according to claim 1, wherein at least the surface of the germanium (Ge) nanoparticles is oxidized.   The manufacturing method of the semiconductor base material in any one of Claims 1-4 with which the said base material is selected from Si wafer, quartz glass, and a ceramic base material.   The manufacturing method of the semiconductor base material in any one of Claims 2-4 which the said base material consists of a plastic film whose melting | fusing point is 200 degreeC or more. The dispersion medium (A) has a vapor pressure of 10 ⁻¹⁰ Pa to ^{10 −5} Pa at 25 ° C., and the concentration of the nonionic surfactant is 0 with respect to 100 parts by mass of the dispersion medium (A). the method of manufacturing a semiconductor substrate according to claim 1 .3～ 50 parts by weight.

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