JP5640331B2 - FIELD EFFECT TRANSISTOR, MANUFACTURING METHOD THEREOF, AND IMAGE DISPLAY DEVICE - Google Patents

Description

  The present invention relates to a field effect transistor, a manufacturing method thereof, and an image display device using the field effect transistor. In particular, the present invention relates to a field effect transistor with improved adhesion between a substrate and a field effect transistor, a method for manufacturing the same, and an image display device.

  In recent years, many of the display devices such as a liquid crystal display, an organic EL display, and an electrophoretic display that have been widely used in recent years use an active matrix type drive device using a thin film transistor (TFT) as a display switching device. For such a TFT as a display switch, a field effect transistor (FET) made of a semiconductor disposed between a gate electrode, a gate insulating layer, a source electrode-drain electrode, and a source electrode-drain electrode is used. The driving principle of the FET is to control the charge transfer between the source electrode and the drain electrode, that is, the current, by controlling the amount of charge carriers consisting of electrons or holes in the semiconductor by applying a voltage to the gate electrode. It plays the role of a switch by a special action.

  Conventionally, the semiconductors of the TFT array as described above are those using amorphous or polycrystalline thin film silicon as a semiconductor. Generally, each layer such as an electrode, a semiconductor, and an insulating layer of a thin film silicon TFT is used. Requires a vacuum process and a high-temperature process of 300 ° C. or higher, and is formed by a relatively complicated and expensive process.

  On the other hand, in recent years, semiconductor materials that can be formed at low temperatures such as transparent oxide semiconductors and organic semiconductors have been developed, and it is possible to realize low-temperature, high-speed, and low-cost processes such as having electrical conductivity characteristics higher than amorphous silicon. It has become. In addition, by adopting a low temperature process, a flexible base material such as a plastic film or paper is adopted, and application to production by roll-to-roll or production of a flexible device is expected.

  In order to form a TFT, a patterning technique by photolithography is generally used. Since strong acids and strong alkalis are used for resist development and peeling in photolithography, etching of semiconductors and electrodes, etc., materials such as electrodes, insulators, and semiconductors formed on the substrate are removed from the substrate by these developers and etchants. There was a problem of peeling. In particular, when a plastic film is used as a substrate, the adhesion between the plastic and the metal or metal oxide is not sufficient, and even if the adhesion is improved by surface treatment of the substrate such as UV / ozone treatment or corona treatment, This problem is remarkable because the bond with the substrate is chemically decomposed by alkali or alkali.

JP 2004-200365 A JP 2001-352068 A JP 2002-28961 A JP 2003-258260 A

  In the present invention, the adhesion between a plastic film substrate and a field effect transistor is chemically enhanced by forming a base layer, and the field effect transistor is formed by a plastic film by immersion in a strong acid or strong alkali used in a photolithography process. To provide a field effect transistor, a method of manufacturing the same, and an image display device that can be manufactured with good reproducibility without peeling from a substrate.

  The invention according to claim 1 of the present invention is a field effect transistor having a substrate, a gate electrode, a gate insulating layer, a source electrode, a drain electrode, and a semiconductor, wherein the polymer compound and the metal are formed on the substrate. A field effect transistor comprising an underlayer containing a mixture with a compound.

  The invention according to claim 2 of the present invention is the field effect transistor according to claim 1, wherein the polymer compound of the underlayer has a bond through a metal and an oxygen atom.

  The invention according to claim 3 of the present invention is characterized in that the underlayer contains an organic molecule having a bond with a polymer compound or metal via an oxygen atom or a nitrogen atom. This is a field effect transistor.

  In the invention according to claim 4 of the present invention, the metal of the underlayer is at least one selected from Group 4 elements, Group 5 elements, Group 6 elements, Group 13 elements, zinc, and tin. The field effect transistor according to any one of claims 1 to 3 is provided.

  The invention according to claim 5 of the present invention is the field effect transistor according to claim 4, wherein the underlayer contains at least two kinds of metals.

  The invention according to claim 6 of the present invention is the field effect transistor according to claim 5, wherein the underlayer contains a silicon compound.

  In the invention according to claim 7 of the present invention, the content ratio of the metal atom in the underlayer and the monomer in the polymer compound is from 1: 1 to 1: 5, and the content ratio of the metal atom to the organic molecule is 1: 7. The field effect transistor according to claim 1, wherein the field effect transistor is 1 or more and 1: 6 or less.

  The invention according to claim 8 of the present invention is the field effect transistor according to any one of claims 1 to 7, wherein the semiconductor is made of a material mainly composed of a metal oxide. is there.

  The invention according to claim 9 of the present invention is the field effect transistor according to any one of claims 1 to 7, wherein the semiconductor is made of a material mainly composed of an organic compound. .

  The invention according to claim 10 of the present invention is the field effect transistor according to any one of claims 1 to 9, wherein the substrate is a flexible substrate.

  The invention according to claim 11 of the present invention is the field effect transistor according to claim 10, characterized in that the substrate is mainly composed of paper or plastic.

  The invention according to claim 12 of the present invention is a field effect type characterized in that a solution containing a polymer compound and a metal compound is applied on a substrate, the solution is dried, and the solution is baked to form an underlayer. This is a method for manufacturing a transistor.

  The invention according to claim 13 of the present invention is the method for manufacturing a field effect transistor according to claim 12, wherein the surface of the substrate is treated before forming the underlayer.

  The invention according to claim 14 of the present invention is the method for producing a field effect transistor according to claim 13, wherein the step of treating the surface of the substrate is a hydrophilic treatment.

  The invention according to claim 15 of the present invention is characterized in that the hydrophilization treatment is any one of UV / ozone treatment, oxygen plasma treatment, nitrogen plasma treatment, and corona treatment. Type transistor manufacturing method.

  In the invention according to claim 16 of the present invention, the metal in the metal compound is at least one selected from Group 4 elements, Group 5 elements, Group 6 elements, Group 13 elements, zinc, and tin. The field-effect transistor manufacturing method according to any one of claims 12 to 15, wherein the field-effect transistor is manufactured.

  The invention according to claim 17 of the present invention is the method for producing a field effect transistor according to any one of claims 12 to 16, wherein at least two kinds of metal compounds are used as the metal compound. Is.

  The invention according to claim 18 of the present invention is the method for producing a field effect transistor according to claim 17, wherein a silicon compound is used as the metal compound.

  The field effect type according to any one of claims 12 to 18, wherein the invention according to claim 19 includes a step of forming a semiconductor made of a material mainly composed of a metal oxide. This is a method for manufacturing a transistor.

  The field effect transistor according to any one of claims 12 to 18, wherein the invention according to claim 20 includes a step of forming a semiconductor made of a material mainly composed of an organic compound. This is a manufacturing method.

  According to a twenty-first aspect of the present invention, there is provided an image display device using the field effect transistor according to any one of the first to eleventh aspects.

  The invention according to claim 22 of the present invention is the image display device according to claim 21, wherein the image display device is any one of a liquid crystal display device, an organic EL, and an electronic paper.

  According to the present invention, the adhesion between the plastic film substrate and the field effect transistor is chemically enhanced by forming the base layer, and the field effect transistor can be obtained by immersion in a strong acid or strong alkali used in the photolithography process. It is possible to provide a field effect transistor, a method for manufacturing the same, and an image display device that can be manufactured with good reproducibility without peeling from the plastic film substrate.

1 is a schematic cross-sectional view showing a field effect transistor according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing a field effect transistor according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing a field effect transistor according to an embodiment of the present invention. It is a schematic diagram which shows the chemical structure of the base layer used for the field effect transistor which concerns on embodiment of this invention. It is a schematic diagram which shows the formation solution of the base layer used for the field effect transistor which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the image display apparatus which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  1 to 3 are schematic sectional views showing a field effect transistor 100 according to an embodiment of the present invention. In the embodiment of the present invention, for example, FIG. 1 shows a bottom gate structure and a bottom contact, and FIG. 2 shows a bottom gate structure and a top contact. FIG. 3 shows a top gate structure. The field effect transistor 100 according to the embodiment of the present invention is not limited to the structure described above, and can be applied to any structure.

  As shown in FIGS. 1 to 3, a field effect transistor 100 according to an embodiment of the present invention includes a substrate 10, a base layer 20, a gate electrode 30, a gate insulating layer 40, a source electrode 50, a drain electrode 60, and a semiconductor. 70.

  As the substrate 10 used for the field effect transistor 100 according to the embodiment of the present invention, any material can be used as long as the surface is insulative, sheet-like, and the surface is flat. For example, paper, soda lime glass, Uses quartz glass, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cycloolefin polymer, polyimide (PI), polyethersulfone (PES), polymethyl methacrylate (PMMA), polycarbonate (PC), polyallylate, etc. can do. In addition, even conductive or semiconductive substrates such as stainless steel sheets, aluminum foils, copper foils, silicon wafers, etc. can be coated or vapor-deposited on the surface with insulating materials such as polymer materials or metal oxides. Can be used. Further, the substrate 10 may be provided with a surface treatment layer such as an easy adhesion layer on the surface, or may be subjected to a surface treatment such as a corona treatment, a plasma treatment, or a UV / ozone treatment as a hydrophilic treatment.

  The underlayer 20 used in the field effect transistor 100 according to the embodiment of the present invention is characterized by containing a mixture of a polymer compound and a metal compound. A mixture of a polymer compound and a metal compound is obtained from a mixture having a bond between a polymer compound skeleton and a metal by mixing and reacting respective precursors in a solution. The reaction may be performed in a solution before the underlayer 20 is formed, or may be performed by heating or drying after the underlayer 20 is applied or printed.

  In the underlayer 20 according to the embodiment of the present invention, the polymer compound and the metal have a bond through an oxygen atom. Specifically, this will be described with reference to FIG. FIG. 4 is a schematic diagram showing a chemical structure of the underlayer 20 used in the field effect transistor 100 according to the embodiment of the present invention. As shown in FIG. 4, in the underlayer 20 according to the embodiment of the present invention, metal atoms are bonded to a polymer via oxygen atoms. M represents a metal atom, R represents an organic molecule, and O represents an oxygen atom. As shown in FIG. 4, the underlayer 20 according to the embodiment of the present invention is crosslinked by bonding a polymer to a metal atom through an oxygen atom or a nitrogen atom.

  As a polymer compound that gives a mixture of a polymer compound and a metal compound, it is necessary to select a polymer that reacts with a metal compound or the like and has a bond via an oxygen atom. For example, a polymer compound having a functional group that can be a precursor that can be converted into a hydroxyl group, an alcohol group, a carboxyl group, an epoxy group, or a substituent thereof is desirable. That is, it is desirable that a functional group exemplified in the monomer unit of the polymer is included in each unit, at regular intervals or at random. Specific polymer materials include acrylic resin or block copolymer, acrylic polyol resin, ester polyol resin, etc. using polyvinyl alcohol, polyvinyl phenol, acetyl cellulose, epoxy resin, hydroxyalkyl acrylate, etc. is not.

  The metal compound precursor that gives a mixture of a polymer compound and a metal compound includes a hydroxyl group, an alcohol group, a carboxyl group, an epoxy group, or a polymer compound having a functional group that can be converted into a substituent thereof. And a compound that can have a bond through an oxygen atom can be used. A metal alkoxide compound, halogenated compound, alkylated compound, cyclopentadienyl compound, amino compound, acetylacetonate compound, isocyanate -To compounds and the like. The specific metal atom is preferably at least one metal selected from Group 4 elements, Group 5 elements, Group 6 elements, Group 13 elements, zinc, and tin. It is preferable that the bond with the intervening polymer compound does not dissociate or hardly dissociates with respect to the acid or alkali. Two or more metal compounds may be used, or metal compounds each having a different metal atom may be used.

  The underlayer 20 according to the embodiment of the present invention may contain a silicon atom when it contains two or more kinds of metal atoms, but is bonded to a polymer compound via an oxygen atom of the silicon atom (silicon-oxygen- Since carbon bonds are not resistant to alkali and the bonds are dissociated, it is necessary to prevent the silicon compound from being mixed in too much. It is preferable that the silicon atom content in the underlayer 20 according to the embodiment of the present invention does not exceed 3 times the amount of other metal atoms. Specific metal compounds include tetraisopropyl titanate, tetrabutyl titanate, titanium tetrakisacetylacetonate, titanium chloride, titanium dioctyloxybis (octylene glycolate), titanium diisopropoxybis (triethanolaminate), titanium Lactate, tetrapropyl zirconate, tetrabutyl zirconate, zirconium tetrakisacetylacetonate, zirconium tributoxymonoacetylacetonate, zirconia chloride, zirconium octoate, tetrakisdimethylaminozirconium, tetrapropylhafnate, tetrabutylhafnate, hafniumtetrakis Acetyl acetonate, hafnium chloride, pentaethyl niobate, pentabutoxy niobate, niobium chloride, pentaethyl Tantalate, pentabutyl tantalate, tantalum chloride, molybdenum chloride, zinc chloride, zinc oxalate, zinc propionate, aluminum isopropoxide, aluminum butoxide, aluminum chloride, triisobutylaluminum, aluminum trisacetylacetonate, indium trisacetylacetonate Indium chloride, tin chloride, butyltin chloride, tetraethyl silicate, tetraisopropyl silicate, tetrabutyl silicate and the like are not limited thereto.

  The underlayer 20 according to the embodiment of the present invention may include a polymer compound or an organic molecule having a bond with a metal atom through a metal atom and an oxygen atom or a nitrogen atom. The organic molecule has a bond with a metal atom in order to obtain structural stability of the underlayer 20 by crosslinking and high insulation, and further, to provide an effect of imparting stability to a highly reactive metal compound, This is to provide a coating solution for forming the underlayer 20 by imparting solubility by mixing them.

  The organic molecule used for the underlayer 20 according to the embodiment of the present invention needs to select an organic molecule having a bond through an oxygen atom or a nitrogen atom by reacting with the polymer compound or the metal compound. For example, a hydroxyl group, alcohol group, aldehyde group, carboxyl group, epoxy group, amino group, isocyano group, imino group, acrylic group, ester group, sulfonic acid group, or a functional group that can be converted into a substituent thereof Organic molecules having groups are desirable. More specifically, ethylene glycol, propylene glycol, glucose, urea, guanidine, phenol, cresol, catechol, catecholamine, melamine, hydroxyethyl acrylate, oxalic acid, malonic acid, succinic acid, adipic acid, phthalic acid, isophthalic acid, Examples include, but are not limited to, terephthalic acid or similar compounds thereof.

  The underlayer 20 according to the embodiment of the present invention is selected from at least one of the above metal atoms, a metal compound corresponding to the metal atom is dissolved in a solvent, and the above-described polymer and organic molecule are appropriately selected. In addition, it can be obtained by dissolving in the same solvent or another kind of solvent and mixing after considering the conditions as appropriate. FIG. 5 is a schematic view showing a solution for forming the underlayer 20 used in the field effect transistor 100 according to the embodiment of the present invention. In the case of only the metal compound, the reactivity of the metal compound is fast and the polymerization proceeds even at room temperature. Therefore, when the amount exceeds a certain amount when used for crosslinking of the polymer, it aggregates and precipitates in the solvent. Thus, by binding organic molecules to a part of the metal compound, the solubility can be controlled and a stable solution can be obtained.

  The content ratio of the monomer in the metal atom and the polymer compound is preferably 1: 1 or more and 1: 5 or less, and the content ratio of the metal atom and the organic molecule is preferably 1: 1 or more and 1: 6 or less. . If the amount of metal atoms mixed is too large for the polymer or organic molecule, the rapidity of the reactivity of the metal compound will cause very fast curing, resulting in poor solubility and a tendency to lower insulation. It is in. In addition, when the amount of metal atoms mixed is too small relative to the polymer or organic molecule, the effect of adding the metal compound cannot be obtained, and resistance to acid or alkali cannot be obtained. At this time, the content ratio of the monomer or organic molecule in the metal atom and polymer in the underlayer 20 can be determined from the elemental composition ratio obtained by an elemental analysis technique such as XPS (X-ray photoelectron spectroscopy). The final mixture of the metal compound, polymer and organic molecule is preferably dissolved in the solution, and when insoluble matter is generated, it is preferably removed by filtering with a PTFE filter or the like. The solvent for dissolving the metal compound, the polymer, and the organic molecule needs to be appropriately selected according to the physical properties so that there is no sudden reaction promotion, and water, alcohol, an organic solvent, or the like can be used. More specifically, water, methanol, ethanol, isopropanol, normal butanol, normal pentanol, normal hexanol, toluene, xylene, mesitylene, tetralin, anisole, acetylacetone, cyclopentanone, cyclohexanone, ethylene glycol, diethylene glycol, pentane, hexane , Heptane, tetrahydrofuran and the like, but not limited thereto. A single solvent may be sufficient as a solvent and multiple types may be mixed.

  The underlayer 20 according to the embodiment of the present invention can be formed by applying or printing the forming solution obtained above, and drying or baking. As a specific forming method, existing wet coating methods such as micro gravure coating, dip coating, screen coating, die coating, and spin coating can be used. The baking temperature is appropriately selected so that the solvent used is almost completely evaporated, the obtained thin film is not redissolved, and sufficient adhesion to the substrate 10 is obtained. When using, it is preferable to select between 60 ° C. and 250 ° C., and when using a substrate 10 having low heat resistance such as a film substrate, the temperature is selected from about 60 ° C. to 200 ° C. The drying and firing may be performed under vacuum.

  Examples of the gate electrode 30, the source electrode 50, and the drain electrode 60 used in the field effect transistor 100 according to the embodiment of the present invention include Al, Cr, Mo, Cu, Au, Pt, Pd, Fe, Mn, and Ag. This metal can be formed by a method such as photolithography after being formed by a method such as PVD, CVD, or plating. In addition, transparent conductive materials such as indium tin oxide (ITO), fluorine doped tin oxide (FTO), aluminum doped zinc oxide (AZO), gallium doped zinc oxide (GZO), PEDOT: PSS, polyaniline, polythiophene, etc. However, it is more preferable to reduce the resistance by using a metal bus electrode when the wiring resistance is relatively high when these are used. In addition, after processing the above metals, transparent oxides, conductive materials such as organic conductive polymers or their precursors into solutions, pastes, nanoparticle dispersions, etc., they are coated by a printing method, dried, It can also be formed by baking, photocuring or aging. The printing method to be used is not particularly limited, but it is possible to use a patternable printing method such as letterpress printing, intaglio printing, planographic printing, reverse offset printing, screen printing, inkjet, thermal transfer printing, dispenser, etc. Since simplification, cost reduction, and high speed can be achieved, it is more preferable. Further, a spin coating, a die coating, a micro gravure coating, a dip coating, and the like may be combined with a patterning method such as photolithography. Further, a combination of the above printing methods may be used.

As the gate insulating layer 40 used for the field effect transistor 100 according to the embodiment of the present invention, silicon oxide, silicon nitride, silicon oxynitride (SiNxOy), aluminum oxide, tantalum oxide, yttrium oxide, hafnium oxide, hafnium aluminum Inorganic materials such as nates, zirconia oxide and titanium oxide, or polyacrylates such as PMMA (polymethyl methacrylate), PVA (polyvinyl alcohol), PS (polystyrene), polyimide, polyester, epoxy resin, polyvinylphenol (PVP), poly Examples include, but are not limited to, vinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polydimethylsiloxane (PDMS), and butadiene rubber. Not. In order to suppress the gate leakage current, the resistivity of the insulating material is preferably 10 ¹¹ Ωcm or more, more preferably 10 ¹⁴ Ωcm or more. The film thickness is preferably 50 nm to 2 μm.

  The gate insulating layer 40 according to the embodiment of the present invention includes a vacuum deposition method, an ion plating method, a sputtering method, a laser ablation method, a plasma CVD (Chemical Vapor Deposition) method, a photo CVD method, a hot wire CVD method, a spin coat method. It can be formed using a method such as a method, a dip coating method, a screen printing method, a micro gravure printing method, or a die coating method. The gate insulating layer 40 may be used as a single layer, or a stacked layer of a plurality of layers may be used. In addition, a material whose composition is inclined toward the growth direction of the layer is also preferably used. The gate insulating layer 40 described above may be subjected to surface treatment such as corona treatment, plasma treatment, UV / ozone treatment, but care must be taken so that the surface roughness due to the treatment does not become rough. The surface of the gate insulating layer 40 is preferably relatively smooth and free from pinholes, protrusions, and undulations.

  In the field effect transistor 100 according to the embodiment of the present invention, a self-assembled monolayer (not shown) may be formed at the interface between the semiconductor layer 70 and its lower layer. That is, in the case of a field effect transistor having a bottom gate structure as shown in FIG. 1 or FIG. 2, on the gate insulating layer 40, and in the case of a field effect transistor having a top gate structure as shown in FIG. Alternatively, a self-assembled monolayer may be formed respectively. The method for forming a self-assembled monolayer includes a method in which a compound that forms a self-assembled monolayer is deposited on a corresponding substrate under vacuum, a method in which a substrate is immersed in a solution of the compound, a Langmuir-Blodgett method, etc. However, the present invention is not limited to these. However, for example, as a method of obtaining only a self-assembled monolayer with a denser and more reliable compound, Langmuir 19, 1159 (2003). And J.A. Phys. Chem. B 110, 21101 (2006). It is more preferable to use the method described in 1. By forming the self-assembled monomolecular film between the interface between the semiconductor 70 and its lower layer, the wettability and surface energy of the semiconductor layer forming surface can be controlled, and the field effect transistor 100 having excellent characteristics can be obtained. Can be produced.

  Before forming the self-assembled monomolecular film, the surface of the gate insulating layer 40 or the base layer 20 may be subjected to surface treatment such as corona treatment, plasma treatment, or UV / ozone treatment. In particular, when the base layer 20 and the semiconductor layer 70 are in contact with each other as in the field-effect transistor 100 shown in FIG. 3, the surface layer 20 is subjected to such a surface treatment, so that the bond between oxygen and metal atoms is reduced. It can be partially cleaved to expose the hydroxyl group. Therefore, a dense self-assembled monomolecular film can be formed on the gate insulating film 30, and the field effect transistor 100 with excellent characteristics can be manufactured.

  As the semiconductor 70 used in the field effect transistor 100 according to the embodiment of the present invention, a metal oxide semiconductor material or an organic semiconductor material can be preferably used. The metal oxide semiconductor material used in the semiconductor 70 according to the embodiment of the present invention is an oxide containing one or more elements of zinc, indium, tin, tungsten, magnesium, and gallium, zinc oxide, indium oxide, Examples include, but are not limited to, materials such as indium zinc oxide, tin oxide, tungsten oxide (WO), and zinc gallium indium oxide (In—Ga—Zn—O). These materials are substantially transparent and have a band gap of 2.8 eV or more, and preferably a band gap of 3.2 eV or more. The structure of these materials may be single crystal, polycrystal, microcrystal, crystal / amorphous mixed crystal, nanocrystal scattered amorphous, or amorphous. The film thickness of the semiconductor 70 is desirably at least 20 nm.

  The semiconductor 70 made of a metal oxide is formed using a sputtering method, a pulse laser deposition method, a vacuum evaporation method, a CVD method, an MBE (Molecular Beam Epitaxy) method, a sol-gel method, etc., preferably a sputtering method, Pulse laser deposition, vacuum deposition, and CVD. Examples of the sputtering method include RF magnetron sputtering method, DC sputtering method, vacuum deposition method include heating evaporation method, electron beam evaporation method, ion plating method, and CVD method include hot wire CVD method and plasma CVD method. It is not something.

  Examples of the organic semiconductor material used in the semiconductor 70 according to the embodiment of the present invention include π-conjugated organic polymers exhibiting semiconductivity, such as polypyrroles, polythiophenes, polyanilines, polyallylamines, fluorenes, and polycarbazoles. , Polyindoles, poly (p-phenylene vinylenes) and the like, low molecular substances having a π-conjugated system, for example, polycyclic aromatic derivatives such as pentacene, phthalocyanine derivatives, perylene derivatives, tetrathiafulvalene derivatives, tetracyano Quinodimethane derivatives, fullerenes, carbon nanotubes and the like can be used, but are not limited thereto. The method for forming the organic semiconductor can be a vacuum deposition method, a CVD method, a printing method using a solution, or the like, but it is applied using a semiconductor soluble in a solvent from the viewpoint of productivity and cost reduction. More preferably, the method is used. When using the printing method, there is no particular limitation, but letterpress printing, intaglio printing, planographic printing, reverse offset printing, screen printing method, ink jet, thermal transfer printing, dispenser, spin coating, die coating, micro gravure coating, dip A coat or the like can be used, and the above printing methods may be used in combination.

  The field effect transistor 100 according to the embodiment of the present invention may be used by further forming a protective layer, an interlayer insulating film, an upper pixel electrode, a protective film, an etching stopper layer, and the like. For the protective layer and interlayer insulating film, polyvinylphenol (PVP), polystyrene (PS), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoro Reactions such as organic polymer compounds such as ethylene (PTFE), polyimide (PI), epoxy resin, polydimethylsiloxane (PDMS), butadiene rubber, or mixtures thereof, or alkoxysilane groups, vinyl groups, acrylate esters, epoxy groups, etc. A mixture with a compound having a functional substituent can be used, and furthermore, oxidation of silicon oxide, titanium oxide, tantalum oxide, aluminum oxide, niobium oxide, zirconium oxide, copper oxide, nickel oxide, indium oxide, hafnium oxide, etc. Thing, there is It can also be used such as composite oxides thereof or oxide mixtures, oxynitride.

  Although the details of the field effect transistor 100 according to the embodiment of the present invention have been described above along the structure of one pixel, the field effect transistor 100 according to the embodiment of the present invention normally has pixels arranged in an array. By arranging them, it can be used as a pixel lighting device of an image display device.

  FIG. 6 is a schematic cross-sectional view showing an example of an image display device 300 using the field effect transistor 100 according to the embodiment of the present invention as a pixel lighting device. As shown in FIG. 6, an image display apparatus 300 according to an embodiment of the present invention is a field effect transistor array in which at least one field effect transistor 100 described above is arranged for each pixel, and is connected to an image display medium 303. To do. Examples of the image display medium 303 include an electrophoretic display medium (electronic paper), a liquid crystal display medium, an organic EL, an inorganic EL, and the like.

  In the example of the image display device 300 according to the embodiment of the present invention shown in FIG. 6, an interlayer insulating film 301 is formed on a substrate 110 on which a field effect transistor 100 is formed, and a source electrode 150 or a drain electrode 160 and a pixel electrode 302 are formed. Are connected, and the image display medium 303 is sandwiched between the pixel electrode 302 and the counter electrode 304. Since the field effect transistor 100 according to the embodiment of the present invention can be made transparent by selecting a material, it may be visible from either the counter electrode 304 side or the field effect transistor 100 side. In the example of the image display device 300 in FIG. 6, the pixel electrode 302 can be disposed on the entire surface of the interlayer insulating film 301. The image display device 200 can be manufactured by attaching an electrophoretic display medium having the counter electrode 302 formed thereon, for example.

  As another example of the image display device 300 according to the embodiment of the present invention, a partition wall for partitioning pixels is formed on the field effect transistor 100, and the pixel electrode 302 is extended from the source electrode 150 or the drain electrode 160. Alternatively, the image display medium 303 may be formed. For example, an organic EL formed using an inkjet method or a printing method can be used as a display medium.

  Hereinafter, the present invention will be described in detail by way of specific examples. However, these examples are for the purpose of explanation, and the present invention is not limited thereto.

First, the solution of the underlayer 20, a tetra -n- butyl titanate _{^{((n BuO) 4 Ti)}} 1g metal compound, a polyvinyl phenol (PVP) 1 g as the polymer, selected methylolmelamine 2g as organic molecules These were dissolved in n-butanol, toluene / n-butanol and toluene / n-butanol solvents, respectively, and mixed by carefully dropping while stirring under an Ar atmosphere to obtain an orange solution. Further, the obtained orange solution was passed through a 0.2 μm PTFE filter to obtain a transparent orange solution.

  Next, 2 mL of the obtained solution is spin-coated on a glass substrate and a PET substrate, dried at 90 ° C. for 10 minutes, and further baked at 120 ° C. for 1 hour to obtain a thin film (underlayer 20) having a thickness of 200 nm. It was. Prior to application of the solution, the glass substrate and the PET substrate were cleaned with a UV / ozone cleaner for 5 minutes.

  When the glass substrate and PET substrate on which the thin film obtained above was formed were immersed in a 2.38% tetramethylammonium hydroxide aqueous solution for 30 minutes, there was no peeling of the thin film.

  The obtained thin film was analyzed by XPS. The inside of the thin film was analyzed by etching with an Ar ion beam for 10 seconds. The content ratio of titanium and PVP monomers was 1: 3, and the content ratio of titanium and methylol melamine was 1: 2.

As in Example 1, first, the solution of the underlayer 20, tetra -n- butyl titanate as a metal compound _{^{((n BuO) 4 Ti)}} 1g, polyvinyl phenol (PVP) 1 g as the polymer, organic molecule 2 g of methylol melamine was selected and dissolved in n-butanol, toluene / n-butanol and toluene / n-butanol solvents, respectively, and a butanol solution of tetrabutyl silicate 1 g was prepared and carefully stirred under an Ar atmosphere. Was added dropwise to give an orange solution. Further, the obtained orange solution was passed through a 0.2 μm PTFE filter to obtain a transparent orange solution.

  Next, 2 mL of the obtained solution was spin-coated on a glass substrate and a PEN substrate, dried at 90 ° C. for 10 minutes, and further baked at 120 ° C. for 1 hour to obtain a thin film (underlayer 20) having a thickness of 200 nm. It was. Prior to application of the solution, the glass substrate and the PET substrate were cleaned with a UV / ozone cleaner for 5 minutes.

  When the glass substrate and the PEN substrate on which the thin film obtained above was formed were immersed in a 2.38% tetramethylammonium hydroxide aqueous solution for 30 minutes, the thin film was not peeled off.

  The obtained thin film was analyzed by XPS. The inside of the thin film was analyzed by etching with an Ar ion beam for 10 seconds. The content ratio of the titanium and PVP monomers was 1: 3, the content ratio of titanium and silicon was 1: 1, and the content ratio of titanium and methylol melamine was 1: 2.

  First, the solution of the underlayer 20 includes 1.5 g of a titanium diisopropoxybis (triethanolamate) 80% solution as a metal compound, 1 g of polyvinyl alcohol (PVA) as a polymer, and 3-amino- 2, g of 1,2,4-triazole was selected, dissolved in water, and mixed by careful dropwise addition with stirring under an Ar atmosphere to obtain a colorless solution. Further, the obtained colorless solution was passed through a 0.2 μm hydrophilic PTFE filter to obtain a transparent solution.

  Next, 2 mL of the obtained solution is spin-coated on a glass substrate and a PEN substrate, dried at 90 ° C. for 10 minutes, and further baked at 150 ° C. for 1 hour to obtain a thin film (underlayer 20) having a thickness of 100 nm. It was. Prior to application of the solution, the glass substrate and the PET substrate were cleaned with a UV / ozone cleaner for 5 minutes.

  When the glass substrate and the PEN substrate on which the thin film obtained above was formed were immersed in a 2.38% tetramethylammonium hydroxide aqueous solution for 30 minutes, there was no peeling of the thin film.

  The obtained thin film was analyzed by XPS. The inside of the thin film was analyzed by etching with an Ar ion beam for 10 seconds. The content ratio of titanium and PVA monomer was 1: 2, and the content ratio of titanium and 3-amino-1,2,4-triazole was 1: 3.

  First, 1 g of tetrabutyl zirconate as a metal compound, 1 g of polyvinylphenol (PVP) as a polymer, and 3 g of methylol melamine as an organic molecule are mixed in the solution of the underlayer 20 in the same manner as in Example 1. A clear solution was obtained.

  Next, 2 mL of the obtained solution is spin-coated on a glass substrate and a PEN substrate, dried at 90 ° C. for 10 minutes, and further baked at 150 ° C. for 1 hour to obtain a thin film (underlayer 20) having a thickness of 100 nm. It was. Prior to application of the solution, the glass substrate and the PET substrate were cleaned with a UV / ozone cleaner for 5 minutes.

  When the glass substrate and the PEN substrate on which the thin film obtained above was formed were immersed in a 2.38% tetramethylammonium hydroxide aqueous solution for 30 minutes, there was no peeling of the thin film.

  The obtained thin film was analyzed by XPS. The inside of the thin film was analyzed by etching with an Ar ion beam for 10 seconds. The content ratio of the zirconium and PVP monomers was 1: 3, and the content ratio of zirconium and methylol melamine was 1: 3.

  A field effect transistor 100 having the same structure as that of FIG. 2 was manufactured. 125 μm-thick PEN was used as the substrate 10, and the surface of one side was subjected to UV / ozone cleaning for 5 minutes, and then the solution of the underlayer 20 produced in Examples 1 to 4 was applied by spin coating at 150 ° C. By baking for 1 hour, the underlayer 20 was formed with a film thickness of 100 nm.

Next, 50 nm of aluminum was formed as a gate electrode 30 on the underlayer 20 by vacuum deposition, and then patterned by photolithography and etching. Subsequently, SiON is formed to a thickness of 350 nm by RF sputtering using a silicon nitride (Si ₃ N ₄ ) target as the gate insulating layer 40 so as to cover the gate electrode 30, and then on the gate insulating layer 40. In addition, as a semiconductor 70, an InGaZnO ₄ target was used to form amorphous In—Ga—Zn—O with a film thickness of 15 nm by an RF sputtering method.

  Next, a resist was applied onto the semiconductor 70, dried and developed, and then ITO was formed to a thickness of 50 nm by DC magnetron sputtering, and lift-off was performed to form the source electrode 50 and the drain electrode 60.

-20V a transfer characteristic of a field-effect transistor 100 obtained from the above the gate voltage 20V, as measured by the drain voltage 15V, mobility ^{3.4cm 2 /Vs~8.2cm 2 / Vs, on} / off is About 10 ⁵ , the threshold voltage was −2V to 5V.

  The peeling of each thin film was not observed by the photolithography process, and the field effect transistor 100 could be manufactured with good reproducibility.

  A field effect transistor 100 having the same structure as that of FIG. 1 was manufactured. 125 μm-thick PEN was used as the substrate 10, and the surface of one side was subjected to UV / ozone cleaning for 5 minutes, and then the solution of the underlayer 20 produced in Examples 1 to 4 was applied by spin coating at 150 ° C. By baking for 1 hour, the underlayer 20 was formed with a film thickness of 100 nm.

Next, 50 nm of aluminum was formed as a gate electrode 30 on the underlayer 20 by vacuum deposition, and then patterned by photolithography and etching. Subsequently, SiON is formed to a thickness of 350 nm by RF sputtering using a silicon nitride (Si ₃ N ₄ ) target as the gate insulating layer 40 so as to cover the gate electrode 30, and then on the gate insulating layer 40. After applying a resist, drying and developing, titanium and gold are successively formed with a film thickness of 5 nm and a film thickness of 50 nm by a vacuum vapor deposition method using an electron beam, respectively, and then lifted off to form the source electrode 50. A pattern was formed as the drain electrode 60.

  Next, an octadecyltrimethoxysilane (OTS) self-assembled monomolecular film (not shown) is formed on the surface of the gate insulating layer 40 by a CVD method, and then pentacene is deposited as a semiconductor 70 at 60 ° C. to a thickness of 40 nm. Thus, a field effect transistor 100 was obtained.

-20V a transfer characteristic of a field-effect transistor 100 obtained from the above the gate voltage 20V, as measured by the drain voltage -15V, mobility ^{0.85cm 2 /Vs~1.2cm 2 / Vs, on} / off Was about 10 ⁵ , and the threshold voltage was −6V to −2V.

  The peeling of each thin film was not observed by the photolithography process, and a field effect transistor could be manufactured with good reproducibility.

[Comparative Example 1]
By making a 10: 1 mixture of PVP and methylolmelamine into a cyclohexanone solution, spin-coating 2 mL of the resulting solution onto a glass substrate and a PET substrate, drying at 90 ° C. for 10 minutes, and further baking at 150 ° C. for 1 hour A thin film having a thickness of 200 nm was obtained. Prior to application of the solution, the glass substrate and the PET substrate were cleaned with a UV / ozone cleaner for 5 minutes.

  When the glass substrate and PET substrate on which the thin film obtained above was formed were immersed in a 2.38% tetramethylammonium hydroxide aqueous solution for 15 minutes, the thin film was peeled off.

[Comparative Example 2]
A mixture of 1 g of PVP and 1 g of methylol melamine is made into a cyclohexanone solution, and a butanol solution of 1 g of tetrabutyl silicate is prepared and mixed by carefully adding dropwise with stirring in an Ar atmosphere. 2 mL of the resulting solution is mixed with a glass substrate and PEN. A thin film having a thickness of 100 nm was obtained by spin coating on a substrate, drying at 90 ° C. for 10 minutes, and baking at 180 ° C. for 1 hour. Prior to application of the solution, the glass substrate and the PEN substrate were cleaned for 5 minutes with a UV / ozone cleaner.

  When the glass substrate and PEN substrate on which the thin film obtained above was formed were immersed in a 2.38% tetramethylammonium hydroxide aqueous solution for 15 minutes, the thin film was peeled off.

  When comparing the field effect transistor 100 according to the example and the comparative example, the base layer 20 is formed on the substrate 10 to chemically improve the adhesion, and the field effect transistor 100 is peeled off from the substrate 10 by photolithography. And can be manufactured with good reproducibility.

  The present invention is used for a field effect transistor (FET) and a display element such as a liquid crystal display element, an organic EL, and an electronic paper having an active matrix TFT array using the same as a back plate.

  DESCRIPTION OF SYMBOLS 10 ... Substrate, 20 ... Underlayer, 30 ... Gate electrode, 40 ... Gate insulating layer, 50 ... Source electrode, 60 ... Drain electrode, 70 ... Semiconductor, 100 ... Field effect transistor, 110 ... Substrate, 120 ... Underlayer, DESCRIPTION OF SYMBOLS 130 ... Gate electrode, 140 ... Gate insulating layer, 150 ... Source electrode, 160 ... Drain electrode, 170 ... Semiconductor, 180 ... Protective layer, 301 ... Interlayer insulating film, 302 ... Pixel electrode, 303 ... Image display medium, 304 ... Opposite Electrode, 300 ... image display device

Claims (18)

A field effect transistor formed with a substrate, a gate electrode, a gate insulating layer, a source electrode, a drain electrode and a semiconductor,
An underlayer containing a mixture of a polymer compound, a metal compound, and an organic molecule on the substrate;
The polymer compound of the underlayer has a bond via a metal and an oxygen atom;
The organic molecule of the underlayer has a bond with the polymer compound or the metal through the oxygen atom or nitrogen atom,
The field effect transistor characterized in that the metal of the underlayer is at least one selected from Group 4 elements, Group 5 elements, Group 6 elements, Group 13 elements, zinc and tin .   The field effect transistor according to claim 1, wherein the underlayer includes at least two kinds of the metals.   The field effect transistor according to claim 2, wherein the underlayer includes a silicon compound.   The content ratio of the metal atom in the underlayer and the monomer in the polymer compound is 1: 1 or more and 1: 5 or less, and the content ratio of the metal atom and the organic molecule is 1: 1 or more and 1: 6 or less. The field effect transistor according to any one of claims 1 to 3, wherein the field effect transistor is.   5. The field effect transistor according to claim 1, wherein the semiconductor is made of a material containing a metal oxide as a main component.   5. The field effect transistor according to claim 1, wherein the semiconductor is made of a material containing an organic compound as a main component.   The field effect transistor according to claim 1, wherein the substrate is a flexible substrate.   8. The field effect transistor according to claim 7, wherein the substrate is mainly composed of paper or plastic. Apply a solution containing a polymer compound, a metal compound, and an organic molecule on the substrate,
Drying the solution;
A method of manufacturing a field effect transistor in which the solution is baked to form a base layer,
The polymer compound of the underlayer has a bond via a metal and an oxygen atom;
The organic molecule of the underlayer has a bond with the polymer compound or the metal through the oxygen atom or nitrogen atom,
The metal in the metal compound is at least one selected from Group 4 elements, Group 5 elements, Group 6 elements, Group 13 elements, zinc, and tin. Production method.   10. The method of manufacturing a field effect transistor according to claim 9, wherein the surface of the substrate is treated before forming the underlayer.   The method for manufacturing a field effect transistor according to claim 10, wherein the step of treating the surface of the substrate is a hydrophilization treatment.   12. The method of manufacturing a field effect transistor according to claim 11, wherein the hydrophilization treatment is any one of UV / ozone treatment, oxygen plasma treatment, nitrogen plasma treatment, and corona treatment.   The method of manufacturing a field effect transistor according to claim 9, wherein at least two kinds of metal compounds are used as the metal compound.   The method of manufacturing a field effect transistor according to claim 13, wherein a silicon compound is used as the metal compound.   15. The method of manufacturing a field effect transistor according to claim 9, further comprising a step of forming a semiconductor made of a material mainly containing a metal oxide.   15. The method for manufacturing a field effect transistor according to claim 9, further comprising a step of forming a semiconductor made of a material containing an organic compound as a main component.   An image display device using the field effect transistor according to claim 1.   The image display device according to claim 17, wherein the image display device is any one of a liquid crystal display device, an organic EL, and an electronic paper.