Coating liquid for forming metal oxide film, oxide insulator film, field effect transistor, display element, image display device and system

Abstract

A field effect transistor comprises: a source and a drain; a gate; a semiconductor layer; and a gate insulating layer, wherein the gate insulating layer is an oxide insulator film containing an A element and a B element, the A element is one or more selected from the group consisting of Zr and Hf, and the B element is one or more selected from the group consisting of Be and Mg.

Description

Technical Field

[0001] The present invention relates to a coating liquid for forming a metal oxide film, an oxide insulator film, a field effect transistor, a display element, an image display device, a system, a method for manufacturing an oxide insulator film, and a method for manufacturing a field effect transistor. Background Art

[0002] In recent years, among flat panel displays, liquid crystal displays (LCDs) or organic EL displays using active matrix thin film transistors (AM-TFTs) as backplanes have become mainstream. Semiconductors used for TFTs are roughly divided into the following three types: amorphous silicon (a-Si), low temperature polycrystalline silicon (LTPS), and oxide semiconductors based on In-Ga-Zn-O (IGZO). Among them, expectations for oxide semiconductor TFTs (hereinafter referred to as oxide TFTs) are high, and research and development have been conducted worldwide (for example, see non-patent document 1).

[0003] Meanwhile, the gate insulating film is a key part constituting the TFT. In industry, SiO2 or SiON films formed by chemical vapor deposition (CVD) have been used since earlier times. In industry, films of SiO2 or SiON formed by chemical vapor deposition (CVD) have been used as gate insulating films in all three types of TFTs.

[0004] In recent years, with the development of larger screen displays, higher resolutions, and finer pixel sizes, there has been an increasing need to improve the mobility of semiconductors and the relative dielectric constant of gate insulating films.

[0005] Therefore, there is a need to provide a field effect transistor using an oxide insulator film having a high dielectric constant.

[0006] Typical methods of forming the semiconductor layer and the gate insulating layer are, for example, sputtering, chemical vapor deposition (CVD), and atomic layer deposition (ALD).

[0007] However, there is a problem that these vacuum processes require complicated and expensive equipment and safety measures regarding the gas source, and the process cost is high. In addition, the limitation of the source gas makes it difficult to freely control the formulation and physical properties of the oxide film.

[0008] In recent years, attention has been paid to the liquid phase method which is easy to implement and can reduce costs. In the liquid phase method, a large-area metal oxide film can be easily produced at a low processing temperature.

[0009] Therefore, even in a field effect transistor using an oxide insulator film having a high dielectric constant, there is a need to provide a field effect transistor having a large area using an oxide insulator film having a high dielectric constant that is easily manufactured at a low process temperature.

[0010] Citation List

[0011] Non-patent literature

[0012] NPL 1: Thin Film Transistors, Cherie R. Kagan (editor), Paul Andry (editor), Publisher: CRC Press (2003 / 2 / 25) Summary of the invention

[0013] Technical issues

[0014] An object of the present invention is to provide a field effect transistor which includes an oxide insulator film having a high dielectric constant as a gate insulating layer and has high performance.

[0015] Technical solutions to the problem

[0016] Means for solving the above-mentioned problems are as follows.

[0017] That is, the field effect transistor of the present invention comprises: a source electrode and a drain electrode; a gate electrode; a semiconductor layer; and a gate insulating layer. The gate insulating layer is an oxide insulator film containing an A element and a B element, wherein the A element is one or more selected from the group consisting of Zr and Hf, and the B element is one or more selected from the group consisting of Be and Mg.

[0018] Beneficial effects of the present invention

[0019] According to the present invention, it is possible to provide a field effect transistor which includes an oxide insulator film having a high dielectric constant as a gate insulating layer and has high performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram showing an example of a bottom-gate / bottom-contact field-effect transistor.

[0021] Figure 2 is a schematic structural diagram showing an example of a bottom-gate / top-contact field-effect transistor.

[0022] Figure 3 is a schematic structural diagram showing an example of a top-gate / bottom-contact field-effect transistor.

[0023] Figure 4 is a schematic structural diagram showing an example of a top-gate / top-contact field-effect transistor.

[0024] Figure 5 is a schematic structural diagram showing an example of a top gate / ILD field effect transistor.

[0025] Fig. 6A is a view showing one example of a method for manufacturing the field effect transistor of the present invention (part 1).

[0026] Figure 6B is a view showing one example of a method for manufacturing the field effect transistor of the present invention (part 2).

[0027] Figure 6C is a view showing one example of a method for manufacturing the field effect transistor of the present invention (Part 3).

[0028] Fig.6D is a view showing one example of a method for manufacturing the field effect transistor of the present invention (Part 4).

[0029] Figure 7 It is a block diagram showing the structure of a television device in another embodiment.

[0030] Figure 8 This is an explanatory diagram (1) of a television set according to another embodiment.

[0031] Fig. 9 This is an explanatory diagram (2) of a television device according to another embodiment.

[0032] Fig.10 This is an explanatory diagram (3) of a television device according to another embodiment.

[0033] Fig.11 This is an explanatory diagram of a display element in another embodiment.

[0034] Fig.12 This is an explanatory diagram of organic EL in another embodiment.

[0035] Fig.13 This is an explanatory diagram (4) of a television device according to another embodiment.

[0036] Fig.14 This is an explanatory diagram (1) of another display element in another embodiment.

[0037] Fig.15 This is an explanatory diagram (2) of another display element in another embodiment. DETAILED DESCRIPTION

[0038] (Coating liquid for forming a metal oxide film)

[0039] The coating liquid for forming a metal oxide film of the present invention contains at least element A and element B, preferably contains element C, and if necessary, also contains other components such as a solvent.

[0040] The coating liquid for forming a metal oxide film includes, for example, at least a metal source, and if necessary, also includes other components such as a solvent. The metal source includes at least a compound containing element A that contains element A and a compound containing element B that contains element B, preferably includes a compound containing element C that contains element C, and if necessary, also contains other components.

[0041] The coating liquid for forming a metal oxide film is a coating liquid for forming a metal oxide film that can easily form a large-area oxide insulator film with a high dielectric constant at a low process temperature.

[0042] The coating liquid for forming a metal oxide film can be suitably used for manufacturing the oxide insulator film of the present invention described below.

[0043] <Element A>

[0044] Element A is one or more elements selected from the group consisting of Zr (zirconium) and Hf (hafnium).

[0045] <Element B>

[0046] Element B is one or more selected from the group consisting of Be (beryllium) and Mg (magnesium).

[0047] <Element C>

[0048] Element C is one or more selected from the group consisting of Sc (scandium), Y (yttrium), and Ln (lanthanide elements).

[0049] Examples of Ln (lanthanide elements) include: La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), and Lu (lutetium).

[0050] <<Solvent>>

[0051] There is no particular limitation on the solvent, and it can be appropriately selected according to the intended purpose. Preferred examples thereof include organic solvents and water.

[0052] <<<Organic solvent>>>

[0053] There is no particular limitation on the organic solvent and it can be appropriately selected according to the intended purpose. The organic solvent is preferably at least one selected from the group consisting of organic acids, organic acid esters, aromatic compounds, glycols, glycol ethers, polar aprotic solvents, alkane compounds, olefin compounds, ether compounds and alcohols.

[0054] -Organic Acids-

[0055] The organic acid is not particularly limited and can be appropriately selected depending on the intended purpose. Preferred examples thereof include acetic acid, lactic acid, propionic acid, octanoic acid, neodecanoic acid, and derivatives thereof.

[0056] These organic acids may be used alone or in combination.

[0057] -Organic acid esters-

[0058] The organic acid ester is not particularly limited and can be appropriately selected depending on the intended purpose. Preferred examples thereof include ethyl acetate, propyl acetate, methyl lactate, propyl propionate, and derivatives thereof.

[0059] These organic acid esters may be used alone or in combination.

[0060] -Aromatic compounds-

[0061] The aromatic compound is not particularly limited and can be appropriately selected depending on the intended purpose. Preferred examples thereof include toluene, xylene, mesitylene, tetralin, cyclohexylbenzene, and derivatives thereof.

[0062] These aromatic compounds may be used alone or in combination.

[0063] -diol-

[0064] The diol is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably an alkanediol and a dialkylene glycol. The diol preferably contains 2 to 6 carbon atoms. The diol is more preferably at least one selected from the group consisting of diethylene glycol, 1,2-ethylene glycol, 1,2-propylene glycol and 1,3-butylene glycol.

[0065] These diols may be used alone or in combination.

[0066] -Diol ether-

[0067] The glycol ether is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably an alkylene glycol monoalkyl ether. The glycol ether preferably contains 3 to 8 carbon atoms.

[0068] Alkylene glycol monoalkyl ether is preferably selected from at least one of the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol-1-monomethyl ether and propylene glycol-1-monobutyl ether. These alkylene glycol monoalkyl ethers have a boiling point of about 120 degrees Celsius to about 180 degrees Celsius, which makes it possible to bake the coating liquid in a short time at a relatively low temperature. And, after baking, an oxide film with less impurities such as carbon and organic matter can be obtained.

[0069] These glycol ethers may be used alone or in combination.

[0070] -Polar aprotic solvents-

[0071] Polar aprotic solvents advantageously dissolve metal sources and exhibit high stability after dissolution. Therefore, when a polar aprotic solvent is used as a coating liquid for forming a metal oxide film, a metal oxide film having high homogeneity and few defects can be obtained.

[0072] The polar aprotic solvent is not particularly limited and can be appropriately selected according to the intended purpose. Preferred examples thereof include isophorone, propylene carbonate, tetrahydrofuran, dihydrofuran-2(3H)-one, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone and derivatives thereof.

[0073] These polar aprotic solvents may be used alone or in combination.

[0074] -Alkane compounds-

[0075] The alkane compound is not particularly limited and can be appropriately selected depending on the intended purpose. For example, n-hexane, cyclohexane, n-nonane, tetradecane, decalin, and derivatives thereof are preferred.

[0076] These alkane compounds may be used alone or in combination.

[0077] -Olefin compounds-

[0078] The olefin compound is not particularly limited and can be appropriately selected depending on the intended purpose. For example, 1-dodecene, 1-tetradecene, and derivatives thereof are preferred.

[0079] These olefin compounds may be used alone or in combination.

[0080] -Ether compounds-

[0081] The ether compound is not particularly limited and can be appropriately selected depending on the intended purpose. For example, tetrahydrofuran, polyethylene glycol, and derivatives thereof are preferred.

[0082] These ether compounds may be used alone or in combination.

[0083] -alcohol-

[0084] The alcohol is not particularly limited and can be appropriately selected depending on the intended purpose. For example, methanol, ethanol, isopropanol, tert-butyl alcohol, and derivatives thereof are preferred.

[0085] These alcohols may be used alone or in combination.

[0086] The coating liquid for forming the metal oxide film is obtained by, for example, dissolving a metal source as a solute in a solvent.

[0087] <Metal Source>

[0088] The metal source is at least one selected from the group consisting of inorganic salts, oxides, hydroxides, metal complexes, and organic acid salts.

[0089] Examples of the inorganic salt include nitrates, sulfates, chlorides, carbonates, acetates, and phosphates. These inorganic salts may be used alone or in combination.

[0090] Examples of organic acid salts include carboxylates, phenols, and derivatives thereof. These organic acid salts may be used alone or in combination.

[0091] Examples of the carboxylates include aliphatic carboxylates, aromatic carboxylates, hydroxycarboxylates, dicarboxylates, tricarboxylates and oxocarboxylates. These carboxylates may be used alone or in combination.

[0092] As long as the metal source as the solute is uniformly dissolved in the solvent, it can be dissociated into ions. In this case, concentration segregation is difficult to occur in the coating liquid for forming the metal oxide film, which enables the coating liquid for forming the metal oxide film to be used for a long time. In addition, the film manufactured by using the coating liquid has a uniform formulation. Therefore, when used in the gate insulating layer and semiconductor layer of a TFT, for example, characteristic uniformity is also advantageous.

[0093] Hereinafter, each metal type will be described one by one in terms of metal sources.

[0094] <<Compounds containing element A>>

[0095] Examples of the compound containing the A element include zirconium-containing compounds and hafnium-containing compounds.

[0096] -Zirconium-containing compounds-

[0097] There is no particular limitation on the zirconium-containing compound and it can be appropriately selected according to the intended purpose. Examples of the zirconium-containing compound include zirconium oxynitrate dihydrate, anhydrous zirconium chloride, hydrated zirconium chloride, zirconium oxysulfate, zirconium acetate tetrahydrate, zirconium oxide, zirconium hydroxide, zirconium acetylacetonate and zirconium 2-ethylhexanoate.

[0098] These zirconium-containing compounds may be synthesized products or commercially available products.

[0099] -Hafnium-containing compounds-

[0100] The hafnium-containing compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the hafnium-containing compound include anhydrous hafnium nitrate, anhydrous hafnium chloride, hafnium chloride tetrahydrofuran complex, hafnium sulfate, hafnium acetate, hafnium oxide, hafnium hydroxide, hafnium acetylacetonate, and hafnium 2-ethylhexanoate.

[0101] These hafnium-containing compounds may be synthesized products or commercially available products.

[0102] <<Compounds containing element B>>

[0103] Examples of the compound containing the B element include a beryllium-containing compound and a magnesium-containing compound.

[0104] -Beryllium compounds-

[0105] There is no particular limitation on the beryllium-containing compound and it can be appropriately selected according to the intended purpose. Examples of the beryllium-containing compound include beryllium nitrate trihydrate, beryllium chloride tetrahydrate, beryllium sulfate tetrahydrate, beryllium acetate, beryllium oxide, beryllium hydroxide, beryllium fluoride, basic beryllium carbonate, beryllium acetylacetonate and basic beryllium propionate.

[0106] These beryllium-containing compounds may be synthesized products or commercially available products.

[0107] -Magnesium compounds-

[0108] There is no particular limitation on the magnesium-containing compound and it can be appropriately selected according to the intended purpose. Examples of the magnesium-containing compound include magnesium nitrate hexahydrate, magnesium chloride hexahydrate, magnesium acetate tetrahydrate, magnesium oxide, magnesium hydroxide, magnesium acetylacetonate, magnesium propionate, magnesium 2-ethylhexanoate, magnesium benzoate tetrahydrate, magnesium lactate trihydrate, magnesium 2-ethylbutyrate, magnesium salicylate tetrahydrate, trimagnesium citrate nonahydrate, and magnesium diphenoxide.

[0109] These magnesium-containing compounds may be synthetic products or commercially available products.

[0110] <<Compounds containing C element>>

[0111] Examples of the C element-containing compound include a scandium-containing compound, an yttrium-containing compound, and a lanthanoid-containing compound.

[0112] - Scandium-containing compounds -

[0113] The scandium-containing compound can be appropriately selected depending on the intended purpose. Examples of the scandium-containing compound include scandium nitrate pentahydrate, scandium chloride hexahydrate, hydrated scandium acetate, scandium oxide, scandium hydroxide, scandium acetylacetonate, and scandium 2-ethylhexanoate.

[0114] These scandium-containing compounds may be synthesized products or commercially available products.

[0115] -Yttrium-containing compounds-

[0116] The yttrium-containing compound can be appropriately selected depending on the intended purpose. Examples of the yttrium-containing compound include yttrium nitrate hexahydrate, yttrium chloride hexahydrate, yttrium acetate tetrahydrate, yttrium oxide, yttrium hydroxide, yttrium acetylacetonate, and yttrium 2-ethylhexanoate.

[0117] These yttrium-containing compounds may be synthesized products or commercially available products.

[0118] -Compounds containing lanthanide elements-

[0119] A lanthanum-containing compound, a cerium-containing compound, and a lutetium-containing compound will be described below as typical examples of the lanthanoid-containing compound.

[0120] - Lanthanum-containing compounds -

[0121] Lanthanum (La) is an example of a lanthanide element (Ln).

[0122] The lanthanum-containing compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the lanthanum-containing compound include lanthanum nitrate hexahydrate, lanthanum chloride heptahydrate, hydrated lanthanum phosphate, hydrated lanthanum acetate, lanthanum oxide, lanthanum hydroxide, lanthanum acetylacetonate, and lanthanum 2-ethylhexanoate.

[0123] These lanthanum-containing compounds may be synthesized products or commercially available products.

[0124] -Cerium-containing compounds-

[0125] Cerium (Ce) is an example of a lanthanide element (Ln).

[0126] The cerium-containing compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the cerium-containing compound include cerium nitrate hexahydrate, cerium chloride heptahydrate, cerium acetate monohydrate, cerium oxide, cerium hydroxide, cerium acetylacetonate, and cerium 2-ethylhexanoate.

[0127] These cerium-containing compounds may be synthesized products or commercially available products.

[0128] -Lutetium-containing compounds

[0129] Lutetium (Lu) is an example of a lanthanide element (Ln).

[0130] There is no particular limitation on the lutetium compound, and it can be appropriately selected according to the intended purpose. Examples of the lutetium compound include: lutetium nitrate hexahydrate, lutetium chloride hexahydrate, lutetium acetate tetrahydrate, lutetium oxide, lutetium hydroxide, lutetium acetylacetonate, and lutetium 2-ethylhexanoate.

[0131] These lutetium compounds can be synthetic products or commercially available products.

[0132] The same description applies to other lanthanide elements such as Pr (praseodymium) and Gd (gadolinium).

[0133] <Method for manufacturing a coating liquid for forming a metal oxide film>

[0134] There is no particular limitation on the method for manufacturing a coating liquid for forming a metal oxide film, and it can be appropriately selected according to the purpose. A specific example of the method is as follows. Specifically, a metal salt diol solution and a metal salt diethylene glycol ether solution are separately manufactured. Then, the metal salt diol solution and the metal salt diethylene glycol ether solution are mixed in a desired ratio.

[0135] The coating liquid for forming a metal oxide film of the present invention is suitable for a coating liquid for manufacturing a metal oxide film. In particular, the coating liquid of the present invention is suitable for a coating liquid for manufacturing a gate insulating layer and an interlayer dielectric of a field effect transistor.

[0136] It should be noted that: in the present invention, the metal oxide may contain nitrogen. That is to say, the metal oxide may be a so-called nitrogen oxide.

[0137] (Oxide insulator film)

[0138] The oxide insulator film of the present invention contains at least element A and element B, preferably contains element C, and may further contain other components as needed.

[0139] The oxide insulator film is an insulating oxide.

[0140] The oxide includes nitrogen oxides.

[0141] <Element A>

[0142] Element A is one or more elements selected from the group consisting of Zr (zirconium) and Hf (hafnium).

[0143] <Element B>

[0144] Element B is one or more selected from the group consisting of Be (beryllium) and Mg (magnesium).

[0145] <Element C>

[0146] The C element is one or more selected from the group consisting of Sc (scandium), Y (yttrium) and Ln (lanthanide elements).

[0147] Examples of Ln (lanthanide elements) include La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium) and Lu (lutetium).

[0148] The electronic configuration of the d orbital of the metal ion contained in the oxide insulator film is preferably d 0 or 10 . The electronic configuration is d 0 or 10 The d orbital of is a closed shell structure. Therefore, there is no absorption in the visible light region, thus presenting a wide band gap energy.

[0149] (Method of Manufacturing Oxide Insulator Film)

[0150] The method for producing an oxide insulator film of the present invention comprises: applying the coating liquid for forming a metal oxide film of the present invention onto an object to be coated; and drying the coating liquid, followed by baking, and further comprising other steps if necessary.

[0151] The object to be coated is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the object to be coated include a glass substrate and a plastic substrate.

[0152] When an oxide insulator film is used in a gate insulating layer and an interlayer dielectric of a field effect transistor, the object to be coated is, for example, a substrate, a gate, and a semiconductor layer. The shape, structure, and size of the substrate are not particularly limited, and can be appropriately selected according to the intended purpose. The material of the substrate is not particularly limited, and can be appropriately selected according to the intended purpose. Examples thereof include glass and plastic.

[0153] There is no particular limitation on the method of coating, and it can be appropriately selected according to the intended purpose. Examples of the method include screen printing, roll coating, dip coating, spin coating, die coating, inkjet and nanoimprinting. Among them, spin coating and die coating are preferred because these methods are easy to combine with existing photolithography techniques.

[0154] There is no particular limitation on drying, and can be appropriately selected according to the intended purpose, as long as the volatile components of the coating solution for forming the metal oxide film can be removed. It should be noted that in drying, the volatile components do not need to be completely removed, and the volatile components can be removed to such an extent that the volatile components do not inhibit baking.

[0155] The baking time is not particularly limited and can be appropriately selected according to the intended purpose, as long as the temperature is equal to or higher than the temperature at which the metal element contained in the coating liquid forms an oxide and the temperature is equal to or lower than the temperature at which the substrate (object to be coated) is thermally deformed. The baking temperature is preferably 150 degrees Celsius to 600 degrees Celsius.

[0156] There is no particular restriction on the atmosphere for baking, and it can be appropriately selected according to the intended purpose. For example, an oxygen-containing atmosphere (e.g., in oxygen and air) is preferred. The above atmosphere can oxidize and gasify organic matter and anions contained in the metal source or solvents to be removed from the film. In addition, when the coating liquid is baked in a nitrogen-containing atmosphere (e.g., in nitrogen and in ammonia vapor), nitrogen can be incorporated into the film to form an oxynitride film. As a result, the physical properties of the film, such as relative dielectric constant and thermal expansion coefficient, can be controlled.

[0157] The time for baking is not particularly limited and can be appropriately selected according to the intended purpose.

[0158] The average thickness of the oxide insulator film to be formed is not particularly limited and can be appropriately selected according to the intended purpose. For example, as a gate insulating layer, the average thickness is preferably 1 nm to 500 nm, more preferably 10 nm to 300 nm, and particularly preferably 50 nm to 200 nm.

[0159] (Field Effect Transistor)

[0160] The field effect transistor of the present invention includes at least: a source electrode and a drain electrode; a gate electrode; a semiconductor layer; and a gate insulating layer; and further includes other components such as a substrate if necessary.

[0161] <Gate>

[0162] The gate electrode is not particularly limited and may be appropriately selected depending on the intended purpose as long as the gate electrode is, for example, an electrode to which a gate voltage is to be applied.

[0163] The material of the gate electrode is not particularly limited and can be appropriately selected according to the intended purpose. Examples of the material include metals (e.g., platinum, palladium, gold, silver, copper, zinc, aluminum, nickel, chromium, tantalum, molybdenum, tungsten, and titanium), alloys of these metals, mixtures of these metals, and stacked films. In addition, examples of the material include conductive oxides (e.g., indium oxide, zinc oxide, tin oxide, gallium oxide, and niobium oxide), composite compounds thereof, mixtures thereof, and stacked films thereof.

[0164] The average thickness of the gate electrode is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably 40 nm to 2 μm, more preferably 70 nm to 1 μm.

[0165] <Source and Drain>

[0166] The source electrode and the drain electrode are not particularly limited and can be appropriately selected depending on the intended purpose.

[0167] The material of the source electrode and the material of the drain electrode are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include the same materials as exemplified in the description of the gate electrode.

[0168] The average thickness of the source electrode and the drain electrode is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably 40 nm to 2 μm, more preferably 70 nm to 1 μm.

[0169] <Semiconductor Layer>

[0170] The semiconductor layer (active layer) is, for example, a semiconductor layer in which a channel is formed between a source electrode and a drain electrode.

[0171] The material of the semiconductor layer is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include polycrystalline silicon (p-Si), amorphous silicon (a-Si), oxide semiconductors, and organic semiconductors such as pentacene. Among them, oxide semiconductors are preferred in terms of the stability of the interface between the semiconductor layer and the gate insulating layer.

[0172] The semiconductor layer can be formed of, for example, an n-type oxide semiconductor.

[0173] The n-type oxide semiconductor constituting the semiconductor layer is not particularly limited and can be appropriately selected according to the intended purpose. The n-type oxide semiconductor preferably contains: at least one selected from the group consisting of indium (In), zinc (Zn), tin (Sn) and titanium (Ti); an alkaline earth metal or a rare earth element; more preferably contains In and an alkaline earth element or a rare earth element.

[0174] Examples of rare earth elements include scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0175] The average thickness of the semiconductor layer is not particularly limited and can be appropriately selected depending on the intended purpose. The average thickness is preferably 1 nm to 200 nm, more preferably 5 nm to 100 nm.

[0176] <Gate Insulation Layer>

[0177] The gate insulating layer is an oxide insulator film.

[0178] The oxide insulator film is the oxide insulator film of the present invention. That is, the oxide insulator film contains at least the A element and the B element, preferably contains the C element, and further contains other components if necessary.

[0179] The gate insulating layer of the field effect transistor preferably has characteristics such as high dielectric constant, high insulation and high chemical durability. In addition, in order to achieve high insulation, a film having a wide band gap energy and being amorphous is preferred.

[0180] Conventionally, as high-k gate insulating films in the CMOS field, many crystalline oxides that are perovskite oxides have been considered, including: Zr, Hf or Ln (e.g., Gd2O3, Pr2O3, LaAlO3, La2O3, ZrO2, HfO2, SrZrO3, CaHfO3, LaScO3 and La2Zr2O7) (Non-patent literature: ISRN Nanotechnology, Vol. 2012, (2012) 35). It is reported that these insulating films have relatively high relative dielectric constant values ​​of about 10 to about 40. However, these insulating films have not yet been put into practical use.

[0181] In order to suppress gate leakage, the grain boundaries present in the polycrystalline film are disadvantageous, and highly amorphous oxides are preferred. From this point of view, in the (Ca, Sr, Ba) O-(Zr, Hf) O2 system, there are perovskite crystal phases and layered perovskite crystal phases with various formulations, and crystals are easily precipitated at relatively low temperatures.

[0182] At the same time, in the (Be, Mg) O-(Zr, Hf) O2 system of the oxide insulator film of the present invention, there is neither a perovskite phase nor a layered perovskite phase, so it is easy to maintain an amorphous film. In addition, the band gap energy becomes larger, so that the insulation is excellent.

[0183] Here, both rare earth oxide (RE2O3) and (Zr, Hf) oxide have high heat resistance, and their melting points are greater than 2000 degrees C. However, in the RE2O3-(Zr, Hf)O2 system, a pyrochlore crystal phase represented by La2Zr2O7 exists, and the crystal phase is generated at a relatively low temperature (for example, 650 degrees Celsius for La2Zr2O7).

[0184] However, the three-component system of (Be,Mg)O-RE2O3-(Zr,Hf)O2, which is a preferred mode of the oxide insulator film of the present invention, can increase the amorphous properties, can expand the band gap energy and can improve the chemical durability, which makes it possible to provide an excellent oxide insulator film.

[0185] In addition, the electronic configuration of the d orbital of the metal ion contained in the oxide insulator film of the present invention is preferably d 0 or 10 . The electronic configuration is d 0 or 10 The d orbital of is a closed shell structure. Therefore, there is no absorption in the visible light region, thus presenting a wide band gap energy.

[0186] The average thickness of the gate insulating layer is not particularly limited and can be appropriately selected depending on the intended purpose. The average thickness is preferably 10 nm to 1 μm, more preferably 30 nm to 300 nm.

[0187] <Substrate>

[0188] The shape, structure, and size of the substrate are not particularly limited and can be appropriately selected depending on the intended purpose.

[0189] The substrate is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the substrate include a glass substrate and a plastic substrate.

[0190] The material of the glass substrate is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the material include alkali-free glass and silica glass.

[0191] The material of the plastic substrate is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the material include polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN).

[0192] Note that it is preferred that the substrate be subjected to pretreatment (eg, oxygen plasma, UV-ozone, and cleaning by UV irradiation) to clean the surface and improve adhesion.

[0193] The structure of the field effect transistor is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the structure include: bottom gate / bottom contact field effect transistor ( Figure 1 ), bottom-gate / top-contact field-effect transistor ( Figure 2 ), top-gate / bottom-contact field-effect transistor ( Figure 3 ), top-gate / top-contact field-effect transistor ( Figure 4 ) and TG-ILD (top gate interlayer dielectric) structures ( Figure 5 ).

[0194] exist Figures 1 to 5, reference numeral 1 denotes a substrate, reference numeral 2 denotes a gate, reference numeral 3 denotes a gate insulating layer, reference numeral 4 denotes a source, reference numeral 5 denotes a drain, 6 denotes a semiconductor layer, reference numeral 7 denotes a first interlayer dielectric, reference numeral 8 denotes a second interlayer dielectric, and reference numeral 9 denotes a third interlayer dielectric.

[0195] The field effect transistor of the present invention can be suitably used as a field effect transistor for pixel driving circuits and logic circuits such as liquid crystal displays, organic EL displays, and electrochromic displays.

[0196] (Method of Manufacturing Field Effect Transistor)

[0197] The method for manufacturing a field effect transistor of the present invention includes: applying the coating liquid for forming a metal oxide film of the present invention to form a gate insulating layer (a step of forming a gate insulating layer), and if necessary, also includes other steps, such as a step of forming a gate electrode, a step of forming a source electrode and a drain electrode, and a step of forming a semiconductor layer.

[0198] <Step of Forming Gate Insulating Layer>

[0199] The step of forming the gate insulating layer is not particularly limited and can be appropriately selected according to the intended purpose, as long as the step is a step of applying the coating solution of the present invention for forming a metal oxide film to form a gate insulating layer. For example, the step includes applying the coating solution of the present invention for forming a metal oxide film and drying the coating solution, and then baking.

[0200] By performing the step of forming the gate insulating layer, the gate insulating layer as the oxide insulator film of the present invention can be obtained.

[0201] There is no particular limitation on the coating method, and it can be appropriately selected according to the intended purpose. Examples of the method include screen printing, roll coating, dip coating, spin coating, die coating, inkjet and nanoimprinting. Among them, spin coating and die coating are preferred because these methods are easy to use in combination with existing photolithography techniques.

[0202] There is no particular limitation on drying, and can be appropriately selected according to the intended purpose, as long as the volatile components of the coating solution for forming the metal oxide film can be removed. It should be noted that in drying, the volatile components do not need to be completely removed, and the volatile components can be removed to such an extent that the volatile components do not inhibit baking.

[0203] The baking time is not particularly limited and can be appropriately selected according to the intended purpose, as long as the temperature is equal to or higher than the temperature at which the metal element contained in the coating liquid forms an oxide and the temperature is equal to or lower than the temperature at which the object to be coated is deformed by heat. The baking temperature is preferably 150 to 600 degrees Celsius.

[0204] There is no particular restriction on the atmosphere for baking, and it can be appropriately selected according to the intended purpose. For example, an oxygen-containing atmosphere (e.g., in oxygen and air) is preferred. The above atmosphere can oxidize and gasify organic matter and anions contained in the metal source or solvents to be removed from the film. In addition, when the coating liquid is baked in a nitrogen-containing atmosphere (e.g., in nitrogen and in ammonia vapor), nitrogen can be incorporated into the film to form an oxynitride film. As a result, the physical properties of the film, such as relative dielectric constant and thermal expansion coefficient, can be controlled.

[0205] The time for baking is not particularly limited and can be appropriately selected according to the intended purpose.

[0206] <Step of forming gate electrode>

[0207] The step of forming the gate electrode is not particularly limited and can be appropriately selected according to the intended purpose as long as the step is a step of forming the gate electrode. Examples of the step include: (i) a step of forming the gate electrode by forming a film by, for example, sputtering or dip coating and then patterning the film by photolithography; and (ii) a step of forming the gate electrode by directly forming a film having a desired pattern by a printing process such as inkjet printing, nanoimprinting, or gravure printing.

[0208] <Step of Forming Source and Drain Electrodes>

[0209] The step of forming the source and drain electrodes is not particularly limited and can be appropriately selected according to the intended purpose, as long as the step is a step of forming the source and drain electrodes to be spaced apart from each other. Examples of the step include: (i) a step of forming the source and drain electrodes by forming a film by, for example, sputtering or dip coating and then patterning the film by photolithography; and (ii) a step of forming the source and drain electrodes by directly forming a film having a desired pattern by a printing process such as inkjet printing, nanoimprinting, or gravure printing.

[0210] <Step of Forming Semiconductor Layer>

[0211] In one embodiment, the step of forming a semiconductor layer is not particularly limited and can be appropriately selected according to the intended purpose, as long as the step is a step of forming a semiconductor layer. Examples of the step include: (i) a step of forming a semiconductor layer by forming a film by, for example, sputtering or dip coating, and then patterning the film by photolithography; and (ii) a step of forming a semiconductor layer by directly forming a film having a desired pattern by a printing process such as inkjet printing, nanoimprinting, or gravure printing.

[0212] Here, we will refer to Figures 6A to 6D A method for fabricating a bottom gate / bottom contact field effect transistor is described.

[0213] First, on a substrate 1 formed of, for example, a glass substrate, a conductive film composed of, for example, aluminum is formed by a sputtering method, and the formed conductive film is patterned by photolithography to form a gate electrode 2 ( Fig. 6A ).

[0214] Next, a gate insulating layer 3 is formed on the gate electrode 2 and the substrate 1 to cover the gate electrode 2 ( Figure 6B ). The gate insulating layer 3 is an oxide insulator film of the present invention, and is obtained, for example, by applying a coating liquid for forming a metal oxide film of the present invention, drying the coating liquid, and then baking.

[0215] Then, a conductive film composed of, for example, ITO is formed on the gate insulating layer 3 by, for example, sputtering, and the formed conductive film is patterned by photolithography to form a source electrode 4 and a drain electrode 5 ( Figure 6C ).

[0216] Then, an oxide semiconductor film is formed on the gate insulating layer 3 by a sputtering method so as to cover the channel region formed between the source electrode 4 and the drain electrode 5, and the formed oxide semiconductor film is patterned by photolithography to form a semiconductor layer 6 ( Fig.6D ).

[0217] As described above, a field effect transistor is manufactured.

[0218] (Display Components)

[0219] The display element of the present invention includes at least a light control element and a driving circuit configured to drive the light control element, and if necessary, further includes other components.

[0220] There is no particular limitation on the optical control element, and it can be appropriately selected according to the intended purpose, as long as the optical control is an element configured to control light output according to a drive signal. Examples of the optical control element include: an organic electroluminescent (EL) element, an electrochromic (EC) element, a liquid crystal element, an electrophoretic element, and an electrowetting element.

[0221] The driving circuit is not particularly limited and can be appropriately selected depending on the intended purpose as long as the driving circuit includes the field effect transistor according to the embodiment. Other components are not particularly limited and can be appropriately selected depending on the intended purpose.

[0222] The display element according to another embodiment includes the field effect transistor according to the embodiment. Therefore, the gate insulating layer 13 has good insulating properties, so that good electrical properties can be obtained. As a result, high-quality display can be achieved.

[0223] (Image display device)

[0224] An image display device of the present invention includes at least a plurality of display elements, a plurality of wirings, and a display control device according to another embodiment, and further includes other components if necessary.

[0225] The plurality of display elements are not particularly limited and may be appropriately selected depending on the intended purpose as long as the plurality of display elements are arranged in a matrix according to another embodiment.

[0226] The plurality of wirings are not particularly limited and may be appropriately selected depending on the intended purpose as long as the plurality of wirings can apply gate voltages and image data signals to field effect transistors in the plurality of display elements, respectively.

[0227] The display control device is not particularly limited and can be appropriately selected depending on the intended purpose as long as the display control device can control the gate voltage and the signal voltage of the field effect transistor respectively via a plurality of wirings corresponding to image data.

[0228] Other components are not particularly limited and can be appropriately selected depending on the intended purpose.

[0229] An image display device according to another embodiment includes a display element including the field effect transistor according to the embodiment, and thus can display a high-quality image.

[0230] (system)

[0231] A system according to the present invention includes at least an image display device and an image data generating device according to another embodiment.

[0232] The image data generating device generates image data based on image information to be displayed and outputs the image data to the image display device.

[0233] The system includes the image display device according to another embodiment, and thus can display image information with high definition.

[0234] Hereinafter, a display element, an image display device, and a system according to another embodiment will be described in detail.

[0235] Figure 7 2 shows a schematic configuration of a television device 500 as a system according to another embodiment. Figure 7 The connecting lines in the figure show the flow of representative signals or representative information, and do not show all the connection relationships between the blocks.

[0236] According to another embodiment, a television device 500 includes, for example, a main control device 501, a tuner 503, an AD converter (ADC) 504, a demodulation circuit 505, a transport stream (TS) decoder 506, a sound decoder 511, a DA converter (DAC) 512, a sound output circuit 513, a speaker 514, an image decoder 521, an image·OSD synthesis circuit 522, an image output circuit 523, an image display device 524, an OSD drawing circuit 525, a memory 531, an operating device 532, a drive interface (drive IF) 541, a hard disk device 542, an optical disk device 543, an IR photodetector 551 and a communication control unit 552.

[0237] The main control device 501 is configured to control the entirety of the television device 500, and includes, for example, a CPU, a flash ROM, and a RAM. The flash ROM stores: for example, a program written in a code that can be decoded by the CPU; and various data for CPU processing. In addition, the RAM is a memory used for operation.

[0238] The tuner 503 is configured to select a preset channel from broadcast waves received by the antenna 610. The ADC 504 is configured to convert an output signal (analog information) of the tuner 503 into digital information. The demodulation circuit 505 is configured to demodulate the digital information from the ADC 504.

[0239] The TS decoder 506 is configured to perform TS decoding on the output signal of the decoding circuit 505 to separate the output signal into sound information and image information. The sound decoder 511 is configured to decode the sound information from the TS decoder 506. The DA converter (DAC) 512 is configured to convert the output signal of the sound decoder 511 into an analog signal.

[0240] The sound output circuit 513 is configured to output the output signal of the DA converter (DAC) 512 to the speaker 514. The image decoder 521 is configured to decode the image information from the TS decoder 506. The image·OSD synthesis circuit 522 is configured to synthesize the output signal of the image decoder 521 and the output signal of the OSD drawing circuit 525.

[0241] The image output circuit 523 is configured to output the output signal of the image·OSD synthesis circuit 522 to the image display device 524. The OSD drawing circuit 525 includes a character generator configured to display characters or graphics on the screen of the image display device 524. The OSD drawing circuit 525 is configured to generate a signal including display information according to instructions from the operating device 532 and the IR photodetector 551.

[0242] The memory 531 is configured to temporarily store audio-visual (AV) data. The operating device 532 includes an input medium (not shown) such as a control panel. The operating device 532 is configured to notify the main control device 501 of various information input by the user. The drive IF 541 is an interactive communication interface. An example of the drive IF 541 is based on the AT attachment package interface (ATAPI).

[0243] The hard disk device 542 includes, for example, a hard disk and a drive device configured to drive the hard disk. The drive device is configured to record data on the hard disk and reproduce the data recorded on the hard disk. The optical disk device 543 is configured to record data on an optical disk (e.g., DVD) and reproduce the data recorded on the optical disk.

[0244] The IR photodetector 551 is configured to receive an optical signal from the remote control transmitter 620 and notify the main control device 501 of the received optical signal. The communication control unit 552 is configured to control communication with the Internet. Various information can be obtained through the Internet.

[0245] like Figure 8 As shown, as an example, the image display device 524 includes a display unit 700 and a display control device 780. Fig. 9 As shown, as an example, the display unit 700 includes a display 710 in which a plurality of display elements 702 are arranged in a matrix form (herein represented by n×m).

[0246] like Fig.10 As shown, as an example, the display 710 includes "n" scan lines (X0, X1, X2, X3, ... Xn-2, Xn-1) arranged at constant intervals along the X-axis direction, "m" data lines (Y0, Y1, Y2, Y3, ... Ym-1) arranged at constant intervals along the Y-axis direction, and "m" power lines (Y0i, Y1i, Y2i, Y3i, ... Ym-1i) arranged at constant intervals along the Y-axis direction. Each display element 702 can be identified by each scan line and each data line.

[0247] like Fig.11As shown, as an example, each display element 702 includes an organic electroluminescent (EL) element 750 and a drive circuit 720 configured to allow the organic EL element 750 to emit light. Specifically, the display 710 is an organic EL display of a so-called active matrix system. The display 710 is a 32-inch color display. It should be noted that the size of the display is not limited to this size.

[0248] like Fig.12 As shown, as an example, the organic EL element 750 includes an organic EL thin film layer 740 , a cathode 712 , and an anode 714 .

[0249] The organic EL element 750 can be arranged, for example, next to a field effect transistor. In this case, the organic EL element 750 and the field effect transistor can be formed on the same substrate. However, the arrangement of the organic EL element 750 and the field effect transistor is not limited to the above arrangement. For example, the organic EL element 750 can be arranged on a field effect transistor. In this case, the gate is required to have transparency. Therefore, a conductive transparent oxide (for example, ITO (indium tin oxide), In2O3, SnO2, ZnO, Ga-doped ZnO, Al-doped ZnO, and Sb-doped SnO2) is used as a gate.

[0250] In the organic EL element 750, Al is used in the cathode 712. Note that Mg-Ag alloy, Al-Li alloy, ITO, etc. can be used. ITO is used for the anode 714. Oxides having conductivity such as In2O3, SnO2, or ZnO and Ag-Nd alloy can be used.

[0251] The organic EL thin film layer 740 includes an electron transport layer 742, a light emitting layer 744, and a hole transport layer 746. The electron transport layer 742 is coupled to the cathode 712, and the hole transport layer 746 is coupled to the anode 714. When a predetermined voltage is applied between the anode 714 and the cathode 712, the light emitting layer 744 emits light.

[0252] like Fig.11 As shown, the driving circuit 720 includes two field effect transistors 810 and 820 and a capacitor 830. The field effect transistor 810 is used as a switching element. The gate G is coupled to a predetermined scan line, and the source S is coupled to a predetermined data line. In addition, the drain D is coupled to one terminal of the capacitor 830.

[0253] The capacitor 830 is configured to store a state, ie, data, of the field effect transistor 810. The other terminal of the capacitor 830 is coupled to a predetermined power line.

[0254] The field effect transistor 820 is configured to supply a large current to the organic EL element 750. A gate G of the field effect transistor 820 is coupled to a drain D of the field effect transistor 810. A drain D of the field effect transistor 820 is coupled to an anode 714 of the organic EL element 750, and a source S of the field effect transistor 820 is coupled to a predetermined current supply line.

[0255] When the field effect transistor 810 becomes the “on” state, the organic EL element 750 is driven by the field effect transistor 820 .

[0256] As an example, Fig.13 As shown, the display control device 780 includes an image data processing circuit 782 , a scan line driving circuit 784 and a data line driving circuit 786 .

[0257] The image data processing circuit 782 determines the brightness 523 of the plurality of display elements 702 in the display 710 based on the output signal of the image output circuit 523. The scan line driving circuit 784 applies voltages to the "n" scan lines respectively according to the instruction of the image data processing circuit 782. The data line driving circuit 786 applies voltages to the "m" data lines respectively according to the instruction of the image data processing circuit 782.

[0258] As is clear from the above description, in the television device 500 according to the embodiment of the present invention, the image decoder 521, the image·OSD synthesis circuit 522, the image output circuit 523 and the OSD drawing circuit 525 constitute image data generating means.

[0259] In the above, the case where the light control element is an organic EL element has been described. However, the light control element is not limited thereto, and may be a liquid crystal element, an electrochromic element, an electrophoretic element, an electrowetting element.

[0260] For example, when the light control element is a liquid crystal element, a liquid crystal display is used as the display 710. In this case, Fig.14 As shown, it is not necessary to provide a current supply line for the display element 703.

[0261] In this case, if Fig.15 As shown, as an example, the driving circuit 730 can be composed of a field effect transistor 840, which is similar to Fig.11 Each field effect transistor (810 and 820) shown in FIG. In the field effect transistor 840, the gate G is coupled to a predetermined scan line, and the source S is coupled to a predetermined data line. In addition, the drain D is coupled to the pixel electrode of the liquid crystal element 770 and the capacitor 760. Fig.15, reference numeral 762 denotes a counter electrode (common electrode) of the capacitor 760 , and reference numeral 772 denotes a counter electrode (common electrode) of the liquid crystal element 770 .

[0262] In the above embodiment, the case where the system is a television device has been described. However, the system is not limited thereto. That is, there is no particular limitation on the system as long as it includes an image display device 524 serving as a device configured to display images and information. For example, the system may be a computer 524 system in which a computer (including a personal computer) is coupled to an image display device.

[0263] The image display device 524 can be used as a display unit in mobile information devices (e.g., mobile phones, portable music players, portable video players, electronic books, and personal digital assistants (PDAs)) and camera devices (e.g., still cameras and video cameras). In addition, the image display device 524 can be used as a display unit for various information in transportation systems (e.g., cars, airplanes, trains, and ships). In addition, the image display device 524 can be used as a display unit for various information in measuring devices, analyzing devices, medical equipment, and advertising media.

[0264] As above, the preferred embodiments, etc. have been described in detail. However, the present invention is not limited to the foregoing embodiments, and various modifications and substitutions may be made to the foregoing embodiments without departing from the scope described in the claims.

[0265] Example

[0266] The present invention will be described below by way of examples, but the present invention should not be construed as being limited to these examples.

[0267] (Example 1-1)

[0268] <Preparation of coating solution for forming oxide insulator film>

[0269] Zirconium oxynitrate dihydrate (0.50 mol) and magnesium nitrate hexahydrate (0.50 mol) were weighed, and then ethylene glycol monomethyl ether (500 mL), propylene glycol (1800 mL), water (1200 mL), and isopropyl alcohol (1800 mL) were added and dissolved to prepare a coating solution for forming oxide insulator film 1-1.

[0270] (Examples 1-2 to 1-12)

[0271] <Preparation of coating solution for forming oxide insulator film>

[0272] In the same manner as in Example 1-1, using the material formulations shown in Tables 1-1 and 1-2, coating liquids for forming oxide insulator films 1-2 to 1-12 of Examples 1-2 to 1-12 were prepared.

[0273] (Reference Examples 1-13 to 1-15)

[0274] <Preparation of coating solution for forming oxide insulator film>

[0275] In the same manner as in Example 1-1, using the material formulations shown in Tables 2-1 and 2-2, coating liquids for forming oxide insulator films 1-13 to 1-15 of Reference Examples 1-13 to 1-15 were prepared.

[0276] [Table 1-1]

[0277]

[0278] [Table 1-2]

[0279]

[0280] [Table 2-1]

[0281]

[0282] [Table 2-2]

[0283]

[0284] In Table 1-1, Table 1-2, Table 2-1, and Table 2-2, the names of materials and solvents are as follows.

[0285] <Solute A>

[0286] ZrO(NO3)2·2H2O:Zirconium oxynitrate dihydrate

[0287] HfCl4: Hafnium chloride

[0288] ZrO(C8H 15 O2)2: Bis(2-ethylhexanoate)zirconium oxide

[0289] ZrCl4·8H2O: Zirconium dichloride octahydrate

[0290] Hf(acac)4:Hafnium acetylacetonate

[0291] Hf(C8H 15 O2)4: Hafnium tetra(2-ethylhexanoate)

[0292] <Solute B>

[0293] Mg(NO3)2·6H2O: Magnesium nitrate hexahydrate

[0294] BeSO4·4H2O: Beryllium nitrate tetrahydrate

[0295] Be(acac)2:Beryllium acetylacetonate

[0296] MgCl2·6H2O: Magnesium chloride hexahydrate

[0297] Mg(C8H 15 O2)2: Magnesium bis(2-ethylhexanoate)

[0298] CaCl2·2H2O: Calcium chloride dihydrate

[0299] BaCl2·2H2O: Barium chloride dihydrate

[0300] SrCl2: Strontium chloride

[0301] <Solute C>

[0302] Gd(C8H 15 O2)3: Gadolinium tris(2-ethylhexanoate)

[0303] LaCl3·7H2O: Lanthanum chloride heptahydrate

[0304] Y(C8H 15 O2)3: Yttrium tris(2-ethylhexanoate)

[0305] La(NO3)3·6H2O: Lanthanum nitrate hexahydrate

[0306] Sc(NO3)3·6H2O: Scandium nitrate hexahydrate

[0307] Ce(C8H 15 O2)3: Cerium tris(2-ethylhexanoate)

[0308] PrCl3·7H2O: Praseodymium nitrate heptahydrate

[0309] LuCl3·7H2O: Lutetium nitrate heptahydrate

[0310] <Solvent D>

[0311] EGME: Ethylene glycol monomethyl ether

[0312] EGIPE: Ethylene glycol monoisopropyl ether

[0313] <Solvent E>

[0314] PG: Propylene glycol

[0315] EG: Ethylene glycol

[0316] CHB: Cyclohexylbenzene

[0317] <Solvent F>

[0318] H2O: water

[0319] <Solvent G>

[0320] IPA: Isopropyl alcohol

[0321] EtOH: ethanol

[0322] MeOH: Methanol

[0323] (Example 2-1)

[0324] Using a spin coater, the coating liquid 1-1 in Table 1-1 and Table 1-2 was printed on an alkali-free glass substrate that had been subjected to UV ozone cleaning. The printing performance was good. The substrate was dried on a hot plate heated to 120°C for 10 minutes and then baked at 400°C in the atmosphere for 1 hour to obtain a transparent oxide film.

[0325] (Examples 2-2 to 2-12)

[0326] In the same manner as in Example 2-1, each of the coating solutions 1-2 to 1-12 in Tables 1-1 and 1-2 was printed / dried / baked to obtain similar transparent oxide films. Similar to the coating solution in Example 2-1, all coating solutions had good printing properties.

[0327] The correspondence between coating liquids 1-2 to 1-12 and Examples 2-2 to 2-12 is as follows.

[0328] Example 2-2: Coating liquid 1-2

[0329] Example 2-3: Coating liquid 1-3

[0330] ·Example 2-4: Coating liquid 1-4

[0331] ·Example 2-5: Coating liquid 1-5

[0332] ·Example 2-6: Coating liquid 1-6

[0333] Example 2-7: Coating liquid 1-7

[0334] Example 2-8: Coating liquid 1-8

[0335] ·Example 2-9: Coating liquid 1-9

[0336] ·Example 2-10: Coating liquid 1-10

[0337] Example 2-11: Coating liquid 1-11

[0338] ·Example 2-12: Coating liquid 1-12

[0339] (Reference Examples 2-13 to 2-15)

[0340] In the same manner as in Example 2-1, each of the coating solutions 1-13 to 1-15 in Tables 2-1 and 2-2 was printed / dried / baked to obtain similar transparent oxide films. Similar to the coating solution in Example 2-1, all coating solutions had good printing properties.

[0341] The correspondence between coating solutions 1-13 to 1-15 and reference examples 2-13 to 2-15 is as follows.

[0342] Reference Example 2-13: Coating Solution 1-13

[0343] Reference Example 2-14: Coating Liquid 1-14

[0344] Reference Example 2-15: Coating Solution 1-15

[0345] (Example 3-1)

[0346] On an alkali-free glass substrate cleaned by UV ozone, 100 nm of Al was deposited as a bottom electrode through a mask. Coating solution 1-1 in Table 1-1 and Table 1-2 was printed thereon by spin coating. The film forming property was good. The substrate was dried at 120°C for 1 hour in an air atmosphere in an oven, and then baked at 400°C for 1 hour in an air atmosphere to obtain an oxide insulator film. Subsequently, 100 nm of Al was deposited as an upper electrode through a mask to form a capacitor structure.

[0347] It can be confirmed that the capacitor manufactured in this embodiment has a relative dielectric constant ε of 10.4 or more in the range of 100 Hz to 1 MHz, and has a high relative dielectric constant. In addition, it can be confirmed that the value of dielectric loss tan δ is a low value of about 2% or less in the range from 100 Hz to 100 kHz.

[0348] (Example 4-1)

[0349] <Preparation of Field Effect Transistor>

[0350] -Formation of active layer-

[0351] The alkali-free glass substrate was ultrasonically cleaned with a neutral detergent, pure water and isopropyl alcohol. The substrate was dried and subjected to UV ozone treatment at 90 degrees Celsius for 10 minutes. On the alkali-free glass substrate, a coating liquid for forming an n-type oxide semiconductor film prepared as follows was applied by a spin coater. The resultant was dried at 120°C for 1 hour in an oven in an air atmosphere, and then baked at 400°C for 1 hour in an air atmosphere to obtain an n-type oxide semiconductor film. Then, an active layer having a predetermined shape was obtained by photolithography.

[0352] -Coating liquid for forming n-type oxide semiconductor film-

[0353] Magnesium chloride hexahydrate [Mg(NO3)2·6H2O] (0.3 mol), indium nitrate trihydrate [In(NO3)3·3H2O] (0.6 mol) and tin chloride pentahydrate [SnCl4·5H2O] (0.01 mol) were weighed. Then, N-methylpyrrolidone [NMP] (1500 mL), propylene glycol (1500 mL), water (1000 mL) and methanol (2000 mL) were added thereto and dissolved to prepare a coating solution for forming an n-type oxide semiconductor film.

[0354] -Formation of source and drain electrodes-

[0355] Next, an aluminum alloy film (100 nm) is formed thereon by DC magnetron sputtering, and patterned by photolithography to form source and drain electrodes. Here, the channel width defined by the length of the source and drain electrodes is set to 30 microns, and the channel length defined by the interval between the source and drain electrodes is set to 10 microns.

[0356] -Formation of Gate Insulation Layer-

[0357] Then, the coating liquid 1-1 was applied by a spin coater.

[0358] The substrate was dried on a hot plate heated to 120° C. for 10 minutes and baked in the atmosphere at 400° C. for 1 hour to obtain a gate insulating layer. The average thickness of the obtained gate insulating layer was about 130 nm.

[0359] - Gate formation -

[0360] A Mo film (100 nm) was formed by DC magnetron sputtering and patterned by photolithography to form a gate electrode.

[0361] -Formation of electrode pads-

[0362] Next, through holes are patterned in the gate insulating layer by photolithography to form electrode pads for the source and drain.

[0363] Finally, annealing was performed at 250° C. for 1 hour in the atmosphere.

[0364] As described above, a field effect transistor is produced.

[0365] (Examples 4-2 to 4-12)

[0366] A field effect transistor was produced in the same manner as in Example 4-1 except that the coating liquid 1-1 was changed to each of the following coating liquids.

[0367] Example 4-2: Coating liquid 1-2

[0368] Example 4-3: Coating liquid 1-3

[0369] Example 4-4: Coating liquid 1-4

[0370] ·Example 4-5: Coating liquid 1-5

[0371] ·Example 4-6: Coating liquid 1-6

[0372] ·Example 4-7: Coating liquid 1-7

[0373] ·Example 4-8: Coating liquid 1-8

[0374] ·Example 4-9: Coating liquid 1-9

[0375] ·Example 4-10: Coating liquid 1-10

[0376] Example 4-11: Coating liquid 1-11

[0377] ·Example 4-12: Coating liquid 1-12

[0378] (Reference Examples 4-13 to 4-15)

[0379] A field effect transistor was produced in the same manner as in Example 4-1 except that the coating liquid 1-1 was changed to the following coating liquids.

[0380] Reference Example 4-13: Coating Solution 1-13

[0381] Reference Example 4-14: Coating Solution 1-14

[0382] Reference Example 4-15: Coating Solution 1-15

[0383] For example, aspects of the present invention are as follows.

[0384] <1> A field effect transistor, comprising:

[0385] Source and drain;

[0386] Gate;

[0387] a semiconductor layer; and

[0388] a gate insulating layer;

[0389] The gate insulating layer is an oxide insulator film containing an A element and a B element, wherein the A element is one or more selected from the group consisting of Zr and Hf, and the B element is one or more selected from the group consisting of Be and Mg.

[0390] <2> according to <1> In the field effect transistor, the semiconductor layer is an oxide semiconductor.

[0391] <3> according to <1> or <2> In the field effect transistor, the oxide insulator film further contains a C element, and the C element is one or more selected from the group consisting of Sc, Y and Ln (lanthanide elements).

[0392] <4> according to <1> to <3> The field effect transistor according to any one of the preceding claims, wherein the electronic configuration of the d orbital of the metal ion contained in the oxide insulator film is d 0 or 10 .

[0393] <5> An oxide insulator film comprising:

[0394] A element, wherein the A element is one or more elements selected from the group consisting of Zr and Hf; and

[0395] B element, wherein the B element is one or more elements selected from the group consisting of Be and Mg.

[0396] <6> according to <5> The oxide insulator film further comprises a C element, wherein the C element is one or more of the group consisting of Sc, Y and Ln (lanthanide elements).

[0397] <7> A coating solution for forming a metal oxide film, the coating solution comprising:

[0398] A element, wherein the A element is one or more elements selected from the group consisting of Zr and Hf; and

[0399] B element, wherein the B element is one or more elements selected from the group consisting of Be and Mg.

[0400] <8> according to <7> The coating solution for forming a metal oxide film further comprises a C element, wherein the C element is one or more of the group consisting of Sc, Y and Ln (lanthanide elements).

[0401] <9> according to <7> or <8> The coating solution for forming the metal oxide film further comprises a solvent.

[0402] <10> A display element, comprising:

[0403] a light control element configured to control light output according to a drive signal; and

[0404] The driving circuit comprises a <1> to <4> The field effect transistor of any one of the above is configured to drive the light control element.

[0405] <11> according to <10> The display element, wherein the light control element includes an electroluminescent element, an electrochromic element, a liquid crystal element, an electrophoretic element or an electrowetting element.

[0406] <12> An image display device configured to display an image corresponding to image data, the image display device comprising:

[0407] A plurality of display elements arranged in a matrix form, each of the plurality of display elements being <10> or <11> The display element;

[0408] a plurality of wirings configured to apply gate voltages to the field effect transistors in the plurality of display elements, respectively; and

[0409] A display control device is configured to control the gate voltages of the field effect transistors via a plurality of wirings in accordance with the image data.

[0410] <13> A system comprising:

[0411] according to <12> The image display device; and

[0412] An image data generating device is configured to generate image data based on image information to be displayed and output the image data to the image display device.

[0413] <14> A method for manufacturing an oxide insulator film, the method comprising: <7> to <9> Any one of the coating solutions for forming a metal oxide film is applied to an object to be coated, and the coating solution is dried, followed by baking.

[0414] <15> A method for manufacturing a field effect transistor including a source electrode and a drain electrode, a gate electrode, a semiconductor layer and a gate insulating layer, the method comprising: coating a <7> to <9> The coating solution for forming a metal oxide film as described in any one of the above is used to form the gate insulating layer.

[0415] Reference numerals list

[0416] 1 substrate

[0417] 2 Gate

[0418] 3 Gate insulation layer

[0419] 4 Source

[0420] 5 Drain

[0421] 6 Semiconductor layer

[0422] 7. First interlayer dielectric

[0423] 8 Second interlayer dielectric

[0424] 9 Third interlayer dielectric

Claims

1. A field effect transistor comprising: source and drain; gate; semiconductor layer; and a gate insulating layer; The gate insulating layer is an oxide insulator film containing element A and element B, wherein element A is one or more selected from the group consisting of Zr and Hf, and element B is one or more selected from the group consisting of Be and Mg. The oxide insulator film is an oxide insulator film of the (Be, Mg)O-(Zr, Hf)O2 system, and neither a perovskite phase nor a layered perovskite phase exists in the oxide insulator film.

2. The field effect transistor according to claim 1, wherein The semiconductor layer is an oxide semiconductor.

3. The field effect transistor according to claim 1 or 2, wherein: The oxide insulator film further contains a C element, and the C element is one or more selected from the group consisting of Sc, Y, and Ln (lanthanide elements).

4. The field effect transistor according to claim 1 or 2, wherein The electronic configuration of the d orbital of the metal ions contained in the oxide insulator film is d 0 or d 10 .

5. An oxide insulator film comprising: A element, wherein the A element is one or more elements selected from the group consisting of Zr and Hf; and B element, wherein the B element is one or more elements selected from the group consisting of Be and Mg, in, The oxide insulator film is an oxide insulator film of a (Be, Mg)O-(Zr, Hf)O2 system, and neither a perovskite phase nor a layered perovskite phase exists in the oxide insulator film. 6 . The oxide insulator film according to claim 5 , further comprising a C element, wherein the C element is one or more selected from the group consisting of Sc, Y, and Ln (lanthanide elements).

7. A coating solution for forming an oxide insulator film, the coating solution comprising: A element, wherein the A element is one or more elements selected from the group consisting of Zr and Hf; and B element, wherein the B element is one or more elements selected from the group consisting of Be and Mg, in, The oxide insulator film is an oxide insulator film of a (Be, Mg)O-(Zr, Hf)O2 system, and neither a perovskite phase nor a layered perovskite phase exists in the oxide insulator film. 8 . The coating liquid for forming an oxide insulator film according to claim 7 , further comprising a C element, wherein the C element is one or more selected from the group consisting of Sc, Y, and Ln (lanthanoid elements). 9 . The coating liquid for forming an oxide insulator film according to claim 7 , further comprising a solvent.

10. A display element comprising: a light control element configured to control light output according to a driving signal; and A driving circuit comprising the field effect transistor according to any one of claims 1 to 4 and configured to drive the light control element.

11. The display element according to claim 10, wherein The light control element includes an electroluminescent element, an electrochromic element, a liquid crystal element, an electrophoretic element or an electrowetting element.

12. An image display device configured to display an image corresponding to image data, the image display device comprising: a plurality of display elements arranged in a matrix, each of the plurality of display elements being a display element according to claim 10 or 11; a plurality of wirings configured to apply gate voltages to the field effect transistors in the plurality of display elements, respectively; and A display control device is configured to control the gate voltages of the field effect transistors via a plurality of wirings in accordance with the image data.

13. A system comprising: The image display device according to claim 12; as well as An image data generating device is configured to generate image data based on image information to be displayed and output the image data to the image display device.

14. A method for manufacturing an oxide insulator film, the method comprising: The coating liquid for forming an oxide insulator film according to any one of claims 7 to 9 is applied to an object to be coated, and the coating liquid is dried, followed by baking.

15. A method for manufacturing a field effect transistor comprising a source electrode, a drain electrode, a gate electrode, a semiconductor layer, and a gate insulating layer, the method comprising: The gate insulating layer is formed by applying the coating liquid for forming an oxide insulator film according to any one of claims 7 to 9.

Images