JP2018125395A - Dispersion liquid for forming semiconductor element, and semiconductor film and semiconductor element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously achieve improvement in film formability and mobility of a semiconductor film and improvement in flexibility thereof.SOLUTION: A dispersion liquid for forming a semiconductor element contains particles and a solvent. The particles have a core-shell structure composed of a core containing a metal oxide and a shell containing an organic compound. The average particle diameter of the particles is 5 nm or more and 500 nm or less. A semiconductor element (100) includes electrodes (140, 150) and a semiconductor film (160) obtained by applying the dispersion liquid, which is in contact with the electrodes (140, 150).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dispersion for forming a semiconductor element, and a semiconductor film and a semiconductor element using the same.

  In recent years, with the development of thin and light display elements such as organic electroluminescence (organic EL) elements, development of materials having high carrier mobility (hereinafter referred to as mobility) as semiconductor elements is required. Currently, metal oxides such as indium, gallium, and zinc oxide, which are high mobility metal oxides, have been developed (Patent Document 1).

  Moreover, the current semiconductor element is mainly silicon, and the process requires an expensive vacuum apparatus and a high temperature process. Further, since photolithography is used, it is necessary to go through a plurality of steps. For this reason, there exists a problem that the manufacturing cost of a semiconductor element is high. Therefore, as a method for forming a layer made of inorganic semiconductor particles having high mobility, a non-vacuum process such as a coating method has been actively studied.

International Publication No. 2005/088726 Pamphlet

  By the way, in the case of an inorganic semiconductor film, a high temperature of about 300 ° C. or higher is required as a thin film formation temperature. For this reason, a glass substrate or a silicon wafer must be used as the substrate for forming the inorganic semiconductor film, and it is extremely difficult to apply to products such as resin substrates that require impact resistance and flexibility.

  Accordingly, an object of the present invention is to provide a semiconductor element-forming dispersion that can simultaneously improve the film formability, mobility, and flexibility of a semiconductor film, and a semiconductor film and a semiconductor element using the same. To do.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.

  That is, one aspect of the dispersion for forming a semiconductor element of the present invention has a core-shell structure that includes particles and a solvent, and the particles include a core that includes a metal oxide and a shell that is an organic compound. The average particle size of the particles is 5 nm or more and 500 nm or less.

The semiconductor device for forming dispersions of the present invention, the mobility of the case of the film is preferably not more than 0.0001 cm ² / Vs or more 10 cm ² / Vs.

  In the dispersion for forming a semiconductor element of the present invention, the relative dielectric constant is preferably 5 or more.

  In the dispersion for forming a semiconductor element of the present invention, the organic compound is preferably a cyano group-containing organic compound.

  Another embodiment of the semiconductor film of the present invention is characterized by a semiconductor film obtained by applying the above-described dispersion for forming a semiconductor element.

  One embodiment of the semiconductor element of the present invention includes an electrode and the semiconductor film described above in contact with the electrode.

  By using the dispersion for forming a semiconductor element of the present invention, it is possible to simultaneously realize the film formability, mobility and flexibility of the semiconductor film.

It is sectional drawing which shows typically an example of the semiconductor element in this Embodiment. It is sectional drawing which shows typically an example of the semiconductor element in this Embodiment. It is sectional drawing which shows typically an example of the semiconductor element in this Embodiment. It is sectional drawing which shows the manufacturing method of the semiconductor element in this Embodiment in order of a process.

  Hereinafter, an embodiment of the present invention (hereinafter abbreviated as “embodiment”) will be described in detail.

(Dispersion)
A semiconductor element dispersion liquid (hereinafter, also simply referred to as a dispersion liquid) according to the present embodiment will be described in detail. The dispersion according to the present embodiment includes particles having a core-shell structure including a core containing a metal oxide and a shell containing an organic compound, and a solvent.

  The dispersion may further contain a dispersant. By adding the dispersant, the dispersant is adsorbed on the outside of the organic compound constituting the shell, or the organic compound and the dispersant react to improve the dispersibility of the particles, and the storage stability of the dispersion also improves. .

  In the present embodiment, the core-shell structure refers to, for example, a state in which the periphery of a core containing a metal oxide is covered with an organic compound layer (shell layer) containing an organic compound. There may be an intermediate layer between the core and the shell layer. Further, it is not necessary to cover the entire surface of the core with the shell layer, and it is preferable to cover 30% or more of the surface area of the core, and more preferably 50% or more. Covering with a shell layer of 30% or more is preferable because the dispersibility and the film formability are improved.

  From the viewpoint of semiconductor properties and dispersion stability, the proportion of the metal oxide in the particles having a core-shell structure is preferably 30% by mass or more and 95% by mass or less, and 35% by mass when the total particle is 100% by mass. % To 90% by mass, more preferably 40% to 85% by mass.

  Further, the average particle size of the particles having a core-shell structure is preferably 5 nm or more and 500 nm or less, more preferably 5 nm or more and 300 nm or less from the viewpoint of semiconductor characteristics and dispersion stability.

  In the dispersion liquid according to the present embodiment, by making the particles have a core-shell structure, the metal oxide constituting the core and the organic compound constituting the shell are uniformly dispersed in the dispersion liquid and the semiconductor film. Therefore, the particles can be prevented from aggregating when the semiconductor film is formed, and the mobility of the semiconductor film is improved. As a result, there is an effect that the film formability, mobility improvement and flexibility improvement of the semiconductor film can be realized at the same time.

  Hereinafter, the constituent elements of the dispersion according to the present embodiment will be described in more detail.

(Metal oxide particles)
The metal oxide particles used in the dispersion according to this embodiment will be described. In the dispersion according to the present embodiment, one of the preferred embodiments of the core containing a metal oxide is metal oxide particles. The metal oxide particles may be composed only of a metal oxide, or may contain a metal other than the metal oxide.

Examples of the metal oxide used for the metal oxide particles include copper oxide (I), copper oxide (II), iron oxide, zinc oxide, silver oxide, titanium oxide (rutile, anatase), and zinc oxide doped with aluminum (AZO). ), Zinc oxide doped with gallium (GZO), indium tin oxide (ITO), tin oxide, tin oxide doped with fluorine (FTO), indium oxide, indium gallium / zinc oxide, nickel oxide, CuAlO ₂ , CuGaO ₂ , SrCu ₂ O ₂ , LaCuOS, LaCuOSe, CuInO ₂ , ZnRh ₂ O _4, 12CaO · 7Al ₂ O ₃ (C12A7), Ga ₂ O _{3 and the} like. Two or more of these metal oxides used for the metal oxide particles may be used in combination.

  The metal oxide is preferably indium oxide or zinc oxide, zinc oxide doped with aluminum (AZO), zinc oxide doped with gallium (GZO) from the viewpoint of transparency, carrier mobility, and low cost. Indium oxide is most preferred.

  The metal oxide particles may be subjected to heat treatment (annealing treatment, etc.) before preparing the dispersion. The heat treatment temperature is preferably 300 ° C. or higher and 1000 ° C. or lower, and more preferably 400 ° C. or higher and 800 ° C. or lower. By performing the heat treatment, the surface defects of the metal oxide can be controlled, leading to an improvement in mobility when a semiconductor film is formed.

  The average particle size of the metal oxide particles is preferably 1 nm or more and 450 nm or less, and more preferably 3 nm or more and 280 nm or less. The average particle diameter of the metal oxide particles is measured using a transmission electron microscope or a scanning electron microscope.

(Indium oxide particles)
Indium oxide (III) (manufactured by Sigma-Aldrich), Indium Oxide Nanoparticulars (manufactured by SkySpring Nanomaterials Inc), indium oxide (SP) (manufactured by Rare Metal Co., Ltd.) However, it is not limited to these.

  A typical method for producing indium oxide particles is to neutralize and precipitate indium ions such as indium chloride aqueous solution by adding alkali such as ammonia or caustic soda to produce indium hydroxide in the atmosphere or reducing atmosphere. A method of crystallizing by heat treatment (baking) at a high temperature of 500 ° C. or higher has been proposed.

  The crystal type of indium oxide is a cubic crystal and a bixbyte type, and can be identified by X-ray diffraction measurement.

  In the X-ray diffraction spectrum of the indium oxide particles, the half width of the main peak is a measure representing the crystallinity of indium oxide. When X-ray diffraction measurement of indium oxide particles is performed, a diffraction peak of (222) plane which is a cubic and bixbyite main peak appears at a diffraction angle 2θ = 30 to 31 °. And the half width can be measured from the main peak. The half width obtained from the X-ray diffraction showing the crystallinity of indium oxide is preferably 5.0 ° or less, more preferably 3.0 ° or less, and more preferably 2.0 ° from the viewpoint of carrier mobility in the indium oxide particles. The following is more preferable. In addition, since the film formability is deteriorated when the crystallinity of the indium oxide particles is too high, the half width is preferably 0.004 ° or more, more preferably 0.01 ° or more, and further preferably 0.1 ° or more. .

(Organic compounds)
The organic compound used in the dispersion according to this embodiment will be described. In light of prevention of carrier recombination and high mobility, the relative dielectric constant of the organic compound is preferably 5 or more and 150 or less, and more preferably 10 or more and 100 or less. Thus, the organic compound functions as a dielectric.

  When the organic compound is a dielectric as described above, it is possible to improve the film-formability by being present around the metal oxide particles as the core, and also has an effect on carrier movement and defect control. .

In this embodiment mode, the organic compound is not particularly limited, but an organic compound including a highly polar atom or a functional group is preferable because of its large dielectric constant. The dipole moment that serves as an index of polarity can be estimated by the sum of the coupling moments. As the organic compound having a relative dielectric constant of 5 or more, a compound having a substituent having a bond moment of 1.4D (D = 3.333564 × 10 ⁻³⁰ Cm) or more is preferable. Examples of the substituent having a bond moment of 1.4D or more include OH, CF, CCl, C═O, N═O, and CN. Examples of organic compounds having these substituents and having a relative dielectric constant of 5 or more include fluorine-based resins, glycerin, thioglycerol, and cyano group-containing organic compounds. From the viewpoint of mobility, fluorine-based resins and cyano group-containing organic compounds are preferred. In particular, a cyano group-containing organic compound is preferable, and further a cyanoethyl group-containing organic compound is preferable.

  Here, the cyano group-containing organic compound is a compound containing one or more cyano groups. The cyano group-containing organic compound is more preferably a cyanoethyl group-containing organic compound. Specific examples of the cyano group-containing organic compound include cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl saccharose (cyanoethyl sucrose), cyanoethyl cellulose, cyanoethyl hydroxyethyl cellulose, cyanoethyl starch, cyanoethyl hydroxypropyl starch, cyanoethyl glycidol pullulan, cyanoethyl sorbitol and the like. .

Specific examples of fluorine-based resin, a _{C 2 F 4-n H n} (n is 0 to 3) a polymer as a skeleton, specifically, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, etc. Is mentioned. Moreover, these may be copolymerized, and based on the fluororesin, it may be copolymerized with another resin. In addition, a part of hydrogen in the chemical formula may be substituted with chlorine. For example, polychlorotrifluoroethylene and the like can be mentioned.

Furthermore, a fluorine ion exchange resin is mentioned as a specific example of a fluorine resin. Specifically, the general formula _{CF 2 = CF-O (CF} 2 CF X) n O- (CF 2) m and fluorinated vinyl compound represented by -W, fluorinated olefin of the formula _CF 2 = CFZ And consisting of at least a binary copolymer. Here, X is F or a perfluoroalkyl group having 1 to 3 carbon atoms, n is an integer of 0 to 3, m is an integer of 1 to 5, Z is H, Cl, F, or carbon It is a perfluoroalkyl group of number 1-3. W is any of the groups represented by COOH, SO ₃ H, SO ₂ F, SO ₂ Cl, SO ₂ Br, COF, COCl, COBr, CO ₂ CH ₃ , and CO ₂ C ₂ H _5. .

  In this embodiment, the organic compound is preferably an organic compound having a molecular weight of 600 or more from the viewpoint of film formability.

(solvent)
Next, the solvent used for the dispersion according to the present embodiment will be described. As the solvent, water, pentane, hexane, peptane, octane, nonane, decane, 2-methylhexane, decalin, tetralin, methanol, ethanol, n-propanol, 2-propanol, n-butanol, t-butanol, ethylene glycol, Diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, ethylene glycol mono 2-ethylhexyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether , Tripropylene glycol n-butyl ether, dipropylene Ketones such as glycol methyl ether, tripropylene glycol methyl ether, glycerin acetone, methyl ethyl ketone, aromatics such as benzene, xylene, toluene, phenol, aniline, diphenyl ether, dimethyl sulfoxide, dimethylformamide, acetonitrile, methyl acetate, tetrahydrofuran, lactic acid Examples include butyl and N-methylpyrrolidone. Moreover, it is also possible to mix and use these.

(Dispersant)
The dispersant that can be added to the dispersion according to the present embodiment will be described. Examples of the dispersant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  Specifically, examples of the anionic surfactant include fatty acid sodium, monoalkyl sulfate, alkylbenzene sulfonate, and monoalkyl phosphate. Examples of the cationic surfactant include alkyl trimethyl ammonium salt, dialkyl dimethyl ammonium salt, alkyl benzyl methyl ammonium salt and the like.

  Examples of amphoteric surfactants include alkyl dimethylamine oxide and alkyl carboxybetaine.

  Nonionic surfactants include polyoxyethylene alkyl ethers, fatty acid sorbitan esters, alkyl polyglycosides, fatty acid ethanolamides, alkyl monoglyceryl ethers, and the like.

  Further, as other dispersing agents, for example, “Disperbyk-102”, “Disperbyk-111”, “Disperbyk-142”, “Disperbyk-145”, “Disperbyk-110”, “Disperbyk-180” manufactured by BYK Chemie, “Disperbyk-2013”, “Byk-9076”, “ANTI-TERRA-U”, “Pricesurf M208F”, “Pricesurf DBS” manufactured by Daiichi Kogyo Seiyaku Co., Ltd. may be mentioned. Also, Triton X-45, Triton X-100, Triton X, Triton A-20, Triton X-15, Triton X-114, Triton X-405, Tween # 20, Tween # 40, Tween # 60, Tween # 80 , Tween # 85, Pluronic F-68, Pluronic F-127, Span 20, Span 40, Span 60, Span 80, Span 83, Span 85, "Surflon S-211", "Surflon S-221" manufactured by AGC Seimi Chemical "Surflon S-231", "Surflon S-232", "Surflon S-233", "Surflon S-242", "Surflon S-243", "Surflon S-611", "No. 3" manufactured by 3M VecFC-4430 "," NovecFC-4432 ", DIC" MegaFuck F-444 "," MegaFuck F-558 ", and the like.

  From the standpoint of improving dispersibility, phosphoric acid polyester-based dispersants, alkylammonium salt-based dispersants, alkylolamine salt-based dispersants, and copolymer-based dispersants having pigment affinity are preferred. Specifically, it is preferable to use “Disperbyk-111”, “Disperbyk-145”, “Disperbyk-180”, and “Disperbyk-2013” manufactured by Big Chemie.

  The addition amount of the dispersant is preferably 0.1% by mass or more and 20% by mass or less, and more preferably 0.2% by mass or more and 10% by mass or less with respect to the entire dispersion from the viewpoint of the stability of the dispersion. .

  As the concentration of the dispersion, when the total of the metal oxide particles, the organic compound and the solvent is 100% by mass, the content of the metal oxide particles is preferably 0.01% by mass or more and 20% by mass or less, more Preferably, it is 0.1 mass% or more and 10 mass% or less, More preferably, it is 0.2 mass% or more and 8 mass% or less.

  Further, the content of the organic compound is preferably 0.01% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 10% by mass or less, and further preferably 0.2% by mass. It is 8% by mass or more.

  The solvent content is preferably 60% by mass or more and 99.98% by mass or less, more preferably 80% by mass or more and 99.8% by mass or less, and still more preferably 84% by mass. Above, it is 99.6 mass% or less.

(Production method of dispersion)
A method for producing the dispersion according to the present embodiment will be described in detail. In a state where the metal oxide particles are dispersed in a solvent, an organic compound dissolved in the solvent is added and subjected to a dispersion treatment with a ball mill (including a planetary ball mill), a bead mill, a high-pressure jet mill, a homogenizer, an ultrasonic disperser or the like. By further dispersing in the state where both the metal oxide particles and the organic compound coexist, a core-shell structure is formed by reaction or interaction between the functional group of the organic compound and the surface of the metal oxide.

  The surface of the metal oxide particles may be modified with an organic functional group in advance. Thereby, dispersibility in a solvent is improved and a uniform semiconductor film can be formed. Examples of the method for modifying the organic functional group include cyanoethylation.

(Semiconductor film)
A semiconductor film manufactured by applying the dispersion liquid of this embodiment will be described in detail. The semiconductor film according to this embodiment includes particles having a core-shell structure in which metal oxide particles are used as a core and an organic compound is used as a shell. The semiconductor film may be a film composed only of the particles, or may be a film composed of the particles and other components. Examples of other components include any one or more of a solvent, a binder component, and an inorganic component.

The semiconductor film (also referred to as a composite body) in this embodiment has the following characteristics.
(1) The content of the metal oxide is 10% by mass or more and 95% by mass or less with respect to the total of 100% by mass of the metal oxide particles and the organic compound.
(2) The content of the organic dielectric is 5% by mass or more and 90% by mass or less with respect to the total of 100% by mass of the metal oxide particles and the organic compound.

  By using a semiconductor film containing metal oxide particles having a core-shell structure and an organic compound, the flexibility of the semiconductor film can be improved.

  By including particles having a core-shell structure, there is an effect of increasing the conduction path of carriers. When a semiconductor film is formed using only metal oxide particles, a large number of portions where the metal oxide particles are not connected to each other are generated. Therefore, by making the metal oxide particles and the organic compound have a core-shell structure, it is possible to increase the number of contacts between the metal oxide particles in a pseudo manner. In addition, even if the metal oxide particles are not actually closely connected, it is presumed that carriers can pass through the inside of the semiconductor film when the organic compound enters at intervals of several nm. Moreover, when there are too many metal oxide particles in a semiconductor film, there exists a problem that the film formability to a board | substrate falls.

  Further, by using a core-shell structure in which the metal oxide is a core and the organic compound is a shell, peripheral oxygen (that is, air existing on the vacant wall of the particle interface) can be blocked. As a result, the number of carriers deactivated by oxygen can be reduced, so that carrier density and mobility can be improved.

  The content of the metal oxide particles in the semiconductor film is preferably 10% by mass or more and 20% by mass or more from the viewpoint of semiconductor characteristics when the total of the metal oxide particles and the organic dielectric is 100% by mass. More preferably, 35% by mass is further preferable, and 40% by mass is even more preferable. Further, from the same viewpoint, the content of the metal oxide particles is preferably 95% by mass or less, more preferably 90% by mass or less, further preferably 85% by mass or less, and still more preferably 80% by mass or less.

  Moreover, 5 mass% or more is preferable from a flexible viewpoint, and, as for content of the organic compound in a semiconductor film, 10 mass% or more is more preferable. Further, from the same viewpoint, the content of the organic compound is preferably 90% by mass or less, more preferably 60% by mass or less, further preferably 40% by mass or less, and further preferably 30% by mass or less.

  In addition, it is preferable that the semiconductor film has a core-shell structure in which the metal oxide particle is a core and the organic compound is a shell because the metal oxide particles can be uniformly dispersed in the semiconductor film.

(Semiconductor element)
The semiconductor element in this embodiment includes an electrode and the semiconductor film described above formed in contact with the electrode.

  Examples of the semiconductor element include a diode, a transistor, a thin film transistor, a memory, a photodiode, a light emitting diode, a light emitting transistor, and a sensor.

  Transistors and thin film transistors (hereinafter collectively referred to as transistor elements) include various display devices such as active matrix display, liquid crystal display, distributed liquid crystal display, electrophoretic display, electrochromic display, organic light emitting display, and electronic paper. It can be used for various display elements such as a particle rotation type display element.

  In these display devices, the transistor element is used for a display pixel switching transistor, a signal driver circuit element, a memory circuit element, a signal processing circuit element, and the like.

  A switching transistor of a display device or a display element (hereinafter collectively referred to as a display device) is disposed in each pixel of the display device and switches a display state of each pixel. Since such an active drive element does not require patterning of the opposing conductive substrate, depending on the circuit configuration, the pixel wiring is simplified compared to a passive drive type display device that does not have a transistor that switches the display state of the pixel. Can be Usually, one to several switching transistors are arranged per pixel. Such a display device has a structure in which a data line and a gate line which are two-dimensionally formed on a substrate surface intersect each other, and the data line and the gate line are respectively joined to the gate electrode, the source electrode and the drain electrode of the transistor. ing. It is possible to divide the data line and the gate line, and to add a current supply line and a signal line.

  Each pixel of the display device can be provided with a function of recording a signal by adding a capacitor in addition to the pixel wiring and the transistor. Furthermore, a driver circuit for data lines and gate lines, a memory circuit for pixel signals, a pulse generator, a signal divider, a controller, and the like can be mounted on the substrate over which the display device is formed.

  When the semiconductor element is a thin film transistor, the element structure may be, for example, a structure of substrate / gate electrode / insulator layer (dielectric layer) / source electrode / drain electrode / semiconductor layer (bottom contact structure), substrate / Semiconductor layer / source electrode / drain electrode / insulator layer (dielectric layer) / gate electrode structure (top gate structure), substrate / gate electrode / insulator layer (dielectric layer) / semiconductor layer / source electrode / drain electrode (Top contact structure) and the like. The insulator layer (dielectric layer) is a gate insulating film, and is made of, for example, an organic compound film having a relative dielectric constant of 3 to 150. A plurality of source electrodes, drain electrodes, and gate electrodes may be provided. Further, a plurality of semiconductor layers may be provided in the same plane or may be provided in a stacked manner.

Mobility of the semiconductor element (e.g., mobility of the thin film transistor described above), in order to use the device for displaying an image is preferably at least 0.0001 cm ² / Vs, more preferably at least 0.001 cm ² / Vs, More preferably, 0.01 cm ² / Vs or more. In other words, the mobility of when the dispersion according to the present embodiment was film is preferably not less than 0.0001 cm ² / Vs, more preferably at least ^{0.001cm 2 / Vs, 0.01cm 2 /} Vs or higher Further preferred.

  As a configuration of the transistor element, in addition to the thin film transistor, any of a MOS (metal-oxide (insulator layer) -semiconductor) type transistor and a bipolar type transistor can be employed. Examples of the element structure of the bipolar transistor include a structure of n-type semiconductor layer / p-type semiconductor layer / n-type semiconductor layer and a structure of p-type semiconductor layer / n-type semiconductor layer / p-type semiconductor layer. An electrode is connected to the semiconductor layer. A semiconductor film containing indium oxide particles and an organic compound of this embodiment is used for at least one of the p-type semiconductor layer and the n-type semiconductor layer.

  When the semiconductor element is a diode, the element structure includes, for example, a structure of electrode / n-type semiconductor layer / p-type semiconductor layer / electrode. The semiconductor film according to this embodiment is used for the p-type semiconductor layer or the n-type semiconductor layer.

  The semiconductor film is in contact with the electrode, and at least a part of the bonding surface between the semiconductor film and the electrode can be a Schottky junction and / or a tunnel junction. Examples of such a junction structure include, for example, an electrode / Schottky junction (tunnel junction) / semiconductor layer / electrode structure, an electrode / semiconductor layer / tunnel junction / semiconductor layer / electrode structure, and an electrode / Schottky junction ( (Tunnel junction) / semiconductor layer / tunnel junction / semiconductor layer / electrode.

  These Schottky junctions and tunnel junctions are not only usable for adjustment of diode characteristics and tunnel junction elements. If a magnetic material or a photoresponsive material is used for the Schottky junction and the tunnel junction, a more sophisticated semiconductor element can be manufactured.

  In addition, a diode can be formed only by applying a Schottky junction and / or a tunnel junction to the semiconductor film according to this embodiment. A semiconductor element having such a junction structure is preferable because a diode or a transistor can be manufactured with a simple structure. Furthermore, various elements such as an inverter, an oscillator, a memory circuit, and a sensor can be formed by bonding a plurality of semiconductor elements having such a bonded structure.

  The semiconductor element of this embodiment can also be used as an arithmetic element or a storage element in an electronic device such as an IC card, a smart card, or an electronic tag. In that case, even if these are a contact type or a non-contact type, they can be applied without any problem.

  These IC cards, smart cards, and electronic tags are composed of a memory, a pulse generator, a signal divider, a controller, a capacitor, and the like, and may further include an antenna and a battery.

  Furthermore, the semiconductor element of this embodiment can be used as a sensor, and can be applied to various sensors such as a gas sensor, a biosensor, a blood sensor, an immune sensor, an artificial retina, and a taste sensor.

  Next, a specific example of a semiconductor element using the semiconductor film of this embodiment will be described. FIG. 1 is a cross-sectional view showing an example of a configuration example of a semiconductor element 100 according to the present embodiment. As shown in FIG. 1, the semiconductor element 100 is a thin film transistor having a bottom contact structure, and includes a substrate 110, a gate electrode 120 formed on the substrate 110, and an insulation formed on the substrate 110 to cover the gate electrode 120. The body layer 130, the source electrode 140, the drain electrode 150, and the semiconductor layer 160 are included. The source electrode 140 is formed on the substrate 110 and covers one end of the gate electrode 120 with the insulator layer 130 interposed therebetween. The drain electrode 150 is formed on the substrate 110 and covers the other end of the gate electrode 120 with the insulator layer 130 interposed therebetween. The semiconductor layer 160 is formed on the gate electrode 120 with the insulator layer 130 interposed therebetween. From the insulator layer 130 that appears between the source electrode 140 and the drain electrode 150 (ie, a gap), the semiconductor layer 160 is formed on the source electrode 140. And over the drain electrode 150.

  Examples of the material of the substrate 110 include glass or resin. Examples of the material for the gate electrode 120, the source electrode 140, and the drain electrode 150 include metals, conductive ceramic materials, carbon, and conductive organic materials. Each material of the gate electrode 120, the source electrode 140, and the drain electrode 150 is more preferably gold, silver, aluminum, copper, indium tin oxide (ITO) from the viewpoint of obtaining good bonding and adhesion with metal oxide or silicon. Or an indium-gallium alloy. The semiconductor layer 160 is a body layer of a thin film transistor (that is, a layer in which a channel is formed), and is formed using a semiconductor film containing indium oxide particles and an organic compound in this embodiment.

  FIG. 2 is a cross-sectional view schematically showing an example of the semiconductor element 200 according to the present embodiment. As shown in FIG. 2, the semiconductor element 200 is a thin film transistor having a top gate structure, and includes a substrate 210, a source electrode 240 and a drain electrode 250 formed on the substrate 210, and a source electrode formed on the substrate 210. 240, the semiconductor layer 260 covering the drain electrode 250, the insulator layer 230 formed on the semiconductor layer 260, and the gate electrode 220 formed on the insulator layer 230. As shown in FIG. 2, the source electrode 240 and the drain electrode 250 are arranged apart from each other. The semiconductor layer 260 is formed from the substrate 210 appearing between the source electrode 240 and the drain electrode 250 (that is, the gap) to the source electrode 240 and the drain electrode 250. The semiconductor layer 260 is formed using a semiconductor film containing indium oxide particles and an organic compound of this embodiment. The gate electrode 220 is formed over the semiconductor layer 260 with the insulator layer 230 interposed therebetween, and the gate electrode 220, the source electrode 240, and the drain electrode 250 connect the insulator layer 230 and the semiconductor layer 260. Are provided so as to face each other.

  FIG. 3 is a cross-sectional view schematically showing an example of the semiconductor element 300 according to the present embodiment. As shown in FIG. 3, the semiconductor element 300 is a thin film transistor having a top contact structure, and includes a substrate 310, a gate electrode 320 formed on the substrate 310, and an insulation formed on the substrate 310 to cover the gate electrode 320. The semiconductor device includes a body layer 330, a semiconductor layer 360 formed over the insulator layer 330, and a source electrode 340 and a drain electrode 350. The semiconductor layer 360 is formed using a semiconductor film containing indium oxide particles and an organic compound of this embodiment. The source electrode 340 is formed on the substrate 310 and covers one end of the semiconductor layer 360. The drain electrode 350 is also formed on the substrate 310 and covers the other end of the semiconductor layer 360. The source electrode 340 and the drain electrode 350 are arranged apart from each other. The gate electrode 320, the source electrode 340, and the drain electrode 350 are provided so as to partially face each other with the insulator layer 330 and the semiconductor layer 360 interposed therebetween.

  Although not illustrated, the semiconductor element according to this embodiment may be a transistor in which a semiconductor layer is interposed between a source electrode and a drain electrode and these three layers are stacked in the film thickness direction. At this time, the gate electrode is preferably disposed in the semiconductor layer or in the vicinity of the source electrode (drain electrode).

  Subsequently, the material of each layer of the semiconductor element will be described. Examples of the material for the substrates 110, 210, and 310 include glass or resin. Examples of the materials of the gate electrodes 120, 220, and 320, the source electrodes 140, 240, and 340 and the drain electrodes 150, 250, and 350 include metals, conductive ceramic materials, carbon, and conductive organic materials. The materials of the gate electrodes 120, 220, 320, the source electrodes 140, 240, 340 and the drain electrodes 150, 250, 350 are more preferably gold from the viewpoint of obtaining good bonding and adhesion with metal oxide or silicon. Silver, aluminum, copper, ITO, or indium-gallium alloy is preferable. The semiconductor layers 160, 260, and 360 are thin film transistor body layers, and are formed of a semiconductor film containing indium oxide particles and an organic compound as described above. Since indium oxide particles and organic compounds have already been described, please refer to them. 1 to 3, the expression “semiconductor layer” is used, but the “semiconductor layer” is formed from a “semiconductor film”. Is not particularly distinguished.

  In addition, the thickness of the semiconductor layers 160, 260, and 360 (semiconductor film) is preferably 0.001 μm (1 nm) or more, more preferably 0.02 μm or more, and even more preferably 0.05 μm or more from the viewpoint of electrical characteristics. From the same viewpoint, the layer thickness of the semiconductor layers 160, 260, 360 (semiconductor film) is preferably 1 μm (1000 nm) or less, more preferably 0.4 μm or less, further preferably 0.2 μm or less, and 0.1 μm. The following are even more preferred:

(Semiconductor element manufacturing method)
As a manufacturing method of the semiconductor element described above, for example, the semiconductor layer is formed by applying the dispersion liquid according to the present embodiment in a predetermined pattern on each of predetermined regions on the electrode formed in advance or on the insulator layer. The method of forming is mentioned. As another method for manufacturing a semiconductor element, there is a method in which after a semiconductor film is formed on a substrate, the semiconductor film is patterned to form a semiconductor layer, and further, an electrode and an insulator layer are formed. . As a patterning method of the semiconductor film at this time, for example, a method of forming a pattern using a method such as screen printing, gravure printing, offset printing, ink jet printing, or spraying can be employed.

  In this embodiment mode, a semiconductor element can be formed over a substrate such as glass or resin. In addition, since the semiconductor film can be formed by a simple method such as printing or application of a solution, a large number of semiconductor elements can be easily formed on a large area at a time. Therefore, a semiconductor element and a device using the semiconductor element (the above-described display element, arithmetic element, memory element, and the like) can be manufactured at low cost. In addition, manufacturing a semiconductor element using a semiconductor film is effective in reducing the thickness and weight of an apparatus using the semiconductor element.

  Next, a method for manufacturing the semiconductor elements 100, 200, and 300 shown in FIGS. 1 to 3 will be described with reference to the drawings.

  4A to 4C are cross-sectional views illustrating the method of manufacturing the semiconductor element 100 according to the present embodiment in the order of steps. As shown in FIG. 4A, first, the gate electrode 120 is formed on the substrate 110.

  Next, as illustrated in FIG. 4B, the upper surface and side surfaces of the gate electrode 120 are covered with an insulator layer 130. Then, as shown in FIG. 4C, a source electrode 140 and a drain electrode 150 are formed over the substrate 110 and the insulator layer 130, respectively. Thereafter, the semiconductor layer 160 is formed, and the gap between the source electrode 140 and the drain electrode 150 is filled with the semiconductor layer 160. Thereby, the semiconductor element 100 shown in FIG. 1 is completed.

  The semiconductor element 200 shown in FIG. 2 can be manufactured in the following process order. That is, the source electrode 240 and the drain electrode 250 are formed on the substrate 210. Next, the semiconductor layer 260 is formed over the substrate 210 to cover the space between the source electrode 240 and the drain electrode 250 and the source electrode 240 and the drain electrode 250. Then, the insulator layer 230 is formed over the semiconductor layer 260. Thereafter, the gate electrode 220 is formed over the insulator layer 230. Thereby, the semiconductor element 200 shown in FIG. 2 is completed.

  Also, the semiconductor element 300 shown in FIG. 3 can be manufactured in the following process order. That is, the gate electrode 320 is formed on the substrate 310. Next, an insulator layer 330 is formed over the substrate 310 to cover the upper surface and side surfaces of the gate electrode 320. Then, a semiconductor layer 360 is formed over the insulator layer 330. After that, the source electrode 340 and the drain electrode 350 are formed over the substrate 310 and the semiconductor layer 360. Thereby, the semiconductor element 300 shown in FIG. 3 is completed.

  The gate electrode, the source electrode, the drain electrode, the insulator layer, and the semiconductor layer, which are components of these semiconductor elements (for example, thin film transistors), can be formed by a method such as printing or coating. For this reason, it is not necessary to manufacture a semiconductor element under vacuum, and it can be performed under normal pressure.

  Examples of materials for the gate electrode, source electrode, and drain electrode (hereinafter referred to as electrode materials) include metals, conductive ceramic materials, carbon, and conductive organic materials. The electrode material is preferably gold, silver, aluminum, copper, indium tin oxide (ITO), or indium-gallium alloy from the viewpoint of good bonding and adhesion to metal oxide or silicon.

  Further, in order to form the gate electrode, the source electrode, and the drain electrode by a method such as printing and coating, the electrode material needs to be in a liquid state. Therefore, a liquid electrode material can be used alone as an electrode material, but a non-liquid electrode material needs to be dispersed in a liquid. Examples of using non-liquid electrode materials dispersed in liquid include powders of gold, silver, copper, indium tin oxide (ITO), osmium, palladium, nickel, cobalt, iron, aluminum, etc. dispersed in liquid An electroconductive paste is mentioned, More preferably, they are gold, aluminum, copper, and indium tin oxide (ITO). Since indium-gallium is a liquid alloy at room temperature, printing can be performed as it is, and the liquid can be fixed with a sealing material or the like.

  Alternatively, for the electrode material, the precursor can be used as long as the precursor is in a liquid form or is easily made into a solution. Examples of such electrode materials include organic metal complexes such as gold, silver, nickel, and indium, and solutions of inorganic metal complexes.

  The material of the insulator layer preferably has a high dielectric constant, and an insulating ceramic material, an organic compound, a polymer, or the like is used. However, since the material of the insulator layer needs to be liquid like the electrode material, a solution, dispersion, or precursor of these materials may be used. For example, an alcoholate, an acetylacetone complex, or a solution thereof can be applied or printed to form a thin film, and the thin film can be converted into an oxide or sulfide by radiation energy such as heat or light to form an insulator layer. As the material for the insulator layer, polymers such as polyvinylidene fluoride, polyacrylonitrile, polyester, liquid crystal polymer, and organic compounds having polarity can be preferably used. Furthermore, a material in which a high dielectric such as a ceramic material is dispersed in these organic compounds can be used as a material for the insulator layer.

  Further, as the substrates 110, 210, 310, glass substrates, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PC (polycarbonate), PP (polypropylene), polyethersulfone, polyimide, cycloolefin polymer, acrylic resin, Any commonly used substrate such as a plastic substrate such as a fluororesin, a melamine resin, and a phenol resin, an aluminum substrate, a stainless steel (SUS) substrate, a clay substrate, and a paper substrate can be used. PET (polyethylene terephthalate), PC (polycarbonate), PP (polypropylene), PEN (polyethylene naphthalate), polyethersulfone, polyimide, cycloolefin polymer, acrylic resin, fluorine resin, melamine from the viewpoint of light weight, flexibility, and low cost A plastic substrate such as a resin or a phenol resin or a paper substrate is preferable.

  Furthermore, if a plurality of printing devices and / or coating devices arranged in series in the order of the manufacturing process are used, a coating liquid for forming a semiconductor layer is continuously printed and / or coated on a continuous substrate (or sheet). be able to. Thereby, an electrode, a dielectric material layer, and a semiconductor layer can be continuously formed on a substrate (or sheet), and a semiconductor element can be manufactured.

  For example, in the case of manufacturing a thin film transistor having a structure (bottom contact structure) of substrate / gate electrode / insulator layer (dielectric layer) / source electrode / drain electrode / semiconductor layer, they are arranged in series in the order of the manufacturing process. The strip-shaped substrate is sequentially passed through the gate electrode printer, the insulator layer printer, the source / drain electrode printer, and the semiconductor layer printer. The strip-shaped substrate is, for example, the above-described sheet. Thereby, the constituent elements of the above-described thin film transistor are continuously formed on the substrate, and the thin film transistor is efficiently manufactured.

  Such a continuous thin film transistor manufacturing method has advantages such as a small equipment load, a shortened process, a significant reduction in the number of workers, and a low cost. In addition, since a large number of thin film transistors can be easily formed on a large-area substrate at a time, a large-area display device can be manufactured at low cost.

  As the printing method and coating method, known methods such as screen printing, gravure printing, offset printing, ink jet printing, spraying method, blade coating and the like can be used. In a plurality of printing devices and / or coating devices, the same printing method and coating method may be employed, or different printing methods and coating methods may be employed for each component.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

<Evaluation method>
Hereinafter, unless otherwise specified, the evaluation was performed under conditions of 25 ° C. and a humidity of 45%.

(1) Average particle diameter The average particle diameter of the particles was measured by a cumulant method using FPAR-1000 manufactured by Otsuka Electronics.

(2) Film thickness The layer thickness of the semiconductor film was measured at the step portion of the film measured by a stylus profiling system (Dektak XTL, manufactured by Bruker Corporation).

(3) Mobility of semiconductor film The mobility of the semiconductor film was measured using a parameter analyzer (4200-SCS manufactured by Keithley). The element structure is not particularly limited, but unless otherwise specified, an n-type silicon wafer with a 200 nm thermal oxide film (electric resistivity is 0.001 to 0.0015 Ω · cm) is used as a substrate, and the film thickness is 2 nm As a wafer with a gold electrode, a titanium electrode having an adhesion layer, 22 nm-thick gold as an electrode, and having a channel length of 50 μm and a channel width of 500 μm was used.

[Example 1]
(Washing process)
The wafer with a gold electrode was washed with semicoclean 56, ultrapure water, acetone, and 2-propanol, and then subjected to UV ozone treatment.

(Dispersion preparation process)
As the indium oxide (In ₂ O ₃ ) particles, indium oxide (III) nanopowder <100 nm particle size (TEM), 99.9% trace metals basis> (manufactured by Sigma-Aldrich) was used.

  The indium oxide particles were annealed at 600 ° C. for 1 hour in air using a muffle furnace SSTR-11K (manufactured by ISUZU). The particles, cyanoethyl saccharose (CR-U, manufactured by Shin-Etsu Chemical Co., Ltd.) and dimethyl sulfoxide (DMSO, manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and added to a container for a planetary ball mill. Then, the dispersion liquid was obtained by mixing and dispersing with a planetary ball mill. The mixing ratio, bead diameter, and ball mill operation time were as shown in Table 1.

  In the obtained dispersion, it was confirmed from the increase in average particle diameter that the particles showed a core-shell structure with indium oxide particles as the core and cyanoethyl saccharose as the shell.

(Film formation process)
The dispersion was applied to a wafer with a gold electrode, and film formation was performed under the spin coating conditions shown in Table 1. As a result, a uniform semiconductor film could be produced. The semiconductor film was dried at 150 ° C. for 10 minutes to obtain a transistor element.

[Example 2]
Except for the mixing ratio of indium oxide, cyanoethyl saccharose, and dimethyl sulfoxide, it is the same as Example 1. In Example 2, as in Example 1, the particles showed a core-shell structure in the obtained dispersion. In addition, a uniform semiconductor film could be produced using the dispersion, and a transistor element was obtained.

[Example 3]
Except for the mixing ratio of indium oxide, cyanoethyl saccharose, and dimethyl sulfoxide, it is the same as Example 1. Also in Example 3, as in Examples 1 and 2, the particles exhibited a core-shell structure in the obtained dispersion. In addition, a uniform semiconductor film could be produced using the dispersion, and a transistor element was obtained.

[Comparative Example 1]
The same as Example 1 except that cyanoethyl saccharose was not mixed and the mixing ratio of indium oxide and dimethyl sulfoxide. In Comparative Example 1, unlike Examples 1 to 3, in the obtained dispersion, the particles were composed only of indium oxide. In Comparative Example 1, a transistor element could be manufactured, but the transistor did not operate as an electrical property.

  Table 1 shows the average particle diameter of the particles in the dispersions obtained in Examples 1 to 3 and Comparative Example 1, the thickness of the semiconductor film, and the mobility. In Table 1, CRU represents cyanoethyl saccharose, the bead diameter represents the diameter of the ball used in the planetary ball mill, and the film thickness and mobility represent the film thickness of the semiconductor film and the carrier in the semiconductor film constituting the transistor element. The mobility of. N. D means that it did not become a transistor element.

  As shown in Table 1, those in which the particles of Examples 1 to 3 had a core-shell structure were transistor elements and exhibited good mobility.

  In particular, the mobility was highest in Example 3. This is probably because the ratio of the metal oxide as the core to the organic compound as the shell is optimal, and as a result of the good film formability, the mobility has increased.

  In addition, this invention is not limited to embodiment described above or each Example. Based on the knowledge of a person skilled in the art, design changes or the like may be added to the embodiments and examples, and the embodiments and examples may be arbitrarily combined, and aspects such changes may also be added. It is included in the scope of the present invention.

  According to the present invention, the film formability, mobility, and flexibility of the semiconductor film can be realized at the same time, so that the present invention can be applied to various semiconductor elements.

100, 200, 300 Semiconductor element 110, 210, 310 Substrate 120, 220, 320 Gate electrode 130, 230, 330 Insulator layer (gate insulating film)
140, 240, 340 Source electrode 150, 250, 350 Drain electrode 160, 260, 360 Semiconductor layer (semiconductor film)

Claims (6)

Particles and a solvent,
The particles have a core-shell structure composed of a core containing a metal oxide and a shell containing an organic compound,
The average particle diameter of the particles is 5 nm or more and 500 nm or less. A semiconductor element-forming dispersion liquid. Mobility on the membrane is a semiconductor device for forming dispersions according to claim 1, characterized in that not more than 0.0001 cm ² / Vs or more 10 cm ² / Vs.   The dispersion for forming a semiconductor element according to claim 1, wherein the organic compound has a relative dielectric constant of 5 or more.   The dispersion for forming a semiconductor element according to any one of claims 1 to 3, wherein the organic compound is a cyano group-containing organic compound.   The semiconductor film obtained by apply | coating the dispersion liquid for semiconductor element formation in any one of Claims 1-4.   A semiconductor element comprising: an electrode; and the semiconductor film according to claim 5 in contact with the electrode.

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