WO2010106920A1 - Method for manufacturing thin film transistor, and thin film transistor - Google Patents

Method for manufacturing thin film transistor, and thin film transistor Download PDF

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Publication number
WO2010106920A1
WO2010106920A1 PCT/JP2010/053530 JP2010053530W WO2010106920A1 WO 2010106920 A1 WO2010106920 A1 WO 2010106920A1 JP 2010053530 W JP2010053530 W JP 2010053530W WO 2010106920 A1 WO2010106920 A1 WO 2010106920A1
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Prior art keywords
thin film
film transistor
metal
layer
metal oxide
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PCT/JP2010/053530
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French (fr)
Japanese (ja)
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誠 本田
桂 平井
千代子 竹村
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コニカミノルタホールディングス株式会社
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Priority to JP2011504807A priority Critical patent/JPWO2010106920A1/en
Publication of WO2010106920A1 publication Critical patent/WO2010106920A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
    • H01L29/7869—Thin film transistors, i.e. transistors with a channel being at least partly a thin film having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02551—Group 12/16 materials
    • H01L21/02554—Oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02565—Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02614—Transformation of metal, e.g. oxidation, nitridation

Definitions

  • the present invention relates to a thin film transistor manufacturing method and a thin film transistor.
  • An organic thin film transistor having a metal oxide film with few defects formed by anodizing the surface of a gate electrode as a gate insulating layer is disclosed (for example, see Patent Documents 3 and 4).
  • An organic thin film transistor having a gate oxide film made of an oxide of a gate electrode material and a gate insulating layer made of an organic compound and improved withstand voltage characteristics is disclosed (for example, refer to Patent Document 5).
  • a metal layer that forms the gate electrode is subjected to a thermal oxidation treatment (temperature condition of 300 ° C. to 600 ° C.) to form a gate insulating layer on the surface of the gate electrode (see, for example, Patent Document 6).
  • a thermal oxidation treatment temperature condition of 300 ° C. to 600 ° C.
  • IZO zinc indium oxide
  • Patent Document 7 Etc.
  • organic thin film transistors have a drawback in that the durability required for electronic devices is a problem, and the devices that can be used are limited.
  • oxide film formation by thermal oxidation treatment is exposed to extremely high temperatures, it is difficult to apply to resin substrates that are now required, and in the case of using an inorganic oxide semiconductor, the nest semiconductor has a low process temperature.
  • a vacuum-type sputtering method is used for film formation, and even if a flexible resin substrate can be applied, there is a problem that efficient production such as so-called roll-to-roll cannot be performed.
  • thermal oxidation or plasma oxidation is used for the oxidation of the precursor.
  • thermal oxidation method is used to oxidize the precursor, it is usually difficult to achieve the required performance unless the treatment is performed at a very high temperature range of 300 ° C. or higher and substantially 550 ° C. or higher.
  • Non-Patent Documents 1, 2, and 3 It is also known that an amorphous oxide semiconductor is formed by thermal oxidation or the like using an organic metal or metal chloride as a precursor (see, for example, Non-Patent Documents 1, 2, and 3).
  • metal alkoxide when metal alkoxide is used as a precursor, high temperature treatment is required, and there is a performance deterioration due to residual carbon.
  • chloride when chloride is used as a precursor, there is a problem of halogen emission.
  • these precursors are often decomposable with respect to water, so that they are often dissolved in an organic solvent and have problems in the production environment.
  • JP 2003-179242 A Japanese Patent Laid-Open No. 2005-223231 JP 2003-258260 A JP 2003-258261 A JP 2004-235298 A US Patent Application Publication No. 2006/0003485 US Pat. No. 7,427,776
  • An object of the present invention is to provide a gate insulating layer that can be manufactured at a low temperature and under atmospheric pressure and has good insulating properties (high insulating strength), and a semiconductor layer. It is an object of the present invention to provide a method for producing a thin film transistor that can be formed on a low substrate, has excellent continuity productivity such as roll-to-roll, and can be produced at high performance and at low cost.
  • the object of the present invention has been achieved by the following constitution.
  • a method of manufacturing a thin film transistor comprising: forming a metal oxide film on a surface of the gate electrode by anodizing the surface of the gate electrode, wherein the gate insulating film is a metal oxide film.
  • the gate electrode contains a metal material selected from the group consisting of tantalum, aluminum, titanium, niobium, zirconium, hafnium, neodymium, chromium, molybdenum, and molybdenum-tantalum alloy. Manufacturing method.
  • a silicon oxide precursor layer is formed on at least a part of the gate insulating film by a solution coating method, an oxidation conversion is performed to form an insulating layer containing silicon oxide, and then a solution coating method is performed on the insulating layer containing silicon oxide.
  • the method for producing a thin film transistor according to 1 or 2 above comprising the steps of: forming a semiconductor precursor layer by oxidation, and oxidizing the semiconductor precursor layer to form a metal oxide semiconductor layer.
  • the semiconductor precursor layer has a step of forming a solution containing water containing a metal salt as a main component on a part of the surface of the gate insulating film by a coating method.
  • the gate electrode is composed of at least two layers of a metal oxide conductive layer and a metal layer containing a metal material from the substrate side, and a gate insulating film is formed by anodizing the metal layer. 10.
  • a gate insulating film having good insulation (high insulation strength) is formed on the surface of the gate electrode at a low temperature and under a normal pressure, and the resulting gate insulating layer can be formed at a low temperature and under a normal pressure. It has been found that by combining with a metal oxide semiconductor layer, a method for manufacturing a thin film transistor that is excellent in productivity, can be manufactured at low cost, and exhibits high gain transistor characteristics can be provided.
  • the surface of the gate electrode has good insulation (high insulation strength) at low temperature and normal pressure.
  • the method of manufacturing a thin film transistor according to the present invention is the method of manufacturing a thin film transistor having a gate electrode, a gate insulating film, a metal oxide semiconductor layer, a source electrode and a drain electrode on a substrate.
  • the film is a metal oxide film
  • the step of forming the metal oxide film on the surface of the gate electrode by anodizing the surface of the gate electrode has a good insulating property on the surface of the gate electrode (insulation A method for manufacturing a thin film transistor exhibiting high gain transistor characteristics is obtained by forming a gate insulating film having high strength and combining the obtained gate insulating film and a metal oxide semiconductor layer.
  • Examples of the anodic oxidation method according to the present invention include a method of anodizing using an oxygen plasma process described in JP 2007-214525 A, JP 2003-258260 A, JP 2003-258261 A, and the like.
  • the wet anodic oxidation method described also referred to as electrochemical anodic oxidation method
  • electrochemical anodic oxidation method From the viewpoint of obtaining a gate insulating film with good insulation (insulation strength), a wet anodic oxidation method ( The electrochemical anodizing method is preferred.
  • the electrochemical anodic oxidation method can be formed at low temperature, and can form a high dielectric constant and high-quality gate insulating film. By combining this with an oxide semiconductor film formed at a low temperature, the heat resistance is low.
  • a thin film transistor which has a flexible plastic or the like as a substrate and has favorable transistor characteristics can be provided.
  • the voltage of a metal oxide film (also referred to as a metal acid underlayer) formed on the surface of a metal layer used as a gate electrode is in the range of 50V to 200V.
  • the voltage application is continued for 1 minute to 120 minutes, and gate insulation is performed in the range of 40 nm to 500 nm (preferably in the range of 100 nm to 250 nm, more preferably in the range of 100 nm to 150 nm). It is preferable to adjust the thickness of the layer.
  • the formed gate insulating film is subjected to a sealing treatment.
  • the anodized film is porous at the time of formation, but by performing sealing treatment, it is possible to close the surface holes and form an insulating film with high smoothness.
  • SiO 2 is preferably capable of good interface formation and various semiconductor materials.
  • the method for forming the buffer layer is not particularly limited, such as CVD and sputtering, but in the present invention, continuous film formation is possible under atmospheric pressure, and at a low temperature of 300 ° C. or lower, preferably 200 ° C. or lower. It is preferable that a film can be formed.
  • the film thickness of the buffer layer for example, a method of forming a SiO 2 by applying a perhydropolysilazane solution and irradiating ultraviolet light of 120 nm to 300 nm at a temperature of 200 ° C. or less. Is preferably in the range of 10 nm to 100 nm.
  • the metal oxide film constituting the gate insulating film according to the present invention tantalum, aluminum, titanium, niobium, zirconium, hafnium, chromium, molybdenum, and molybdenum-tantalum alloy, which are metal materials used as a gate electrode to be described later It is preferable that it is comprised from the oxide of the metal material selected from the metal material group formed from.
  • the metal oxide semiconductor layer according to the present invention forms a semiconductor precursor layer (also referred to as a metal oxide precursor thin film), and then converts the semiconductor precursor layer into a metal oxide semiconductor layer by means such as baking. It is preferably formed through a process.
  • a solution obtained by dissolving a metal salt selected from nitrate, sulfate, phosphate, carbonate, acetate or oxalate in an appropriate solvent is used on a substrate. It is preferable to coat continuously, and productivity can be improved significantly.
  • metal in the metal salt Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rb , Sr, Y, Zr, Nb, Mo, Cd, In, Ir, Sn, Sb, Cs, Ba, La, Hf, Ta, W, Tl, Pb, Bi, Ce, Pr, Nd, Pm, Eu, Gd , Tb, Dy, Ho, Er, Tm, Yb, Lu and the like.
  • these metal salts preferably contain one or more of any of indium (In), tin (Sn), and zinc (Zn), and may be used in combination. .
  • the other metal contains a salt of either gallium (Ga) or aluminum (Al).
  • composition ratio of metal By the method of the present invention, a metal oxide semiconductor thin film containing a single metal atom or a plurality of metal atoms selected from the metal atoms described above is produced.
  • the metal oxide semiconductor any state of single crystal, polycrystal, and amorphous can be used, but an amorphous thin film is preferably used.
  • the ratio of metal C is 0 to 2 in the above formula. Although the reason is not clear, it is presumed that the oxidation reaction temperature of the precursor material containing metal C is relatively high.
  • the solvent for dissolving the metal salt is not particularly limited as long as it dissolves the metal compound to be used in addition to water.
  • Water alcohols such as ethanol, propanol and ethylene glycol, ethers such as tetrahydrofuran and dioxane, Esters such as methyl acetate and ethyl acetate, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, glycol ethers such as diethylene glycol monomethyl ether, acetonitrile, and aromatic solvents such as xylene and toluene, hexane, cyclohexane, and tridecane ⁇ -terpineol, alkyl halide solvents such as chloroform and 1,2-dichloroethane, N-methylpyrrolidone, carbon disulfide and the like can be used.
  • aqueous solution using water as a solvent.
  • the solvent according to the present invention may be a single solvent or a mixed solvent.
  • the above metal salts such as nitrates are not decomposable with respect to water, and water can be used as a solvent, so that they can be preferably used in the production process and the environment.
  • metal salts such as metal chlorides are severely deteriorated and decomposed in the atmosphere (particularly in the case of gallium, etc.) and strong deliquescence.
  • inorganic salts such as nitrates according to the present invention are deliquescent and deteriorated. It is also preferable in terms of manufacturing environment that it is easy to use.
  • metal salts according to the present invention nitrates that exhibit excellent properties in terms of performance such as degradation, decomposition, and easy dissolution in water and deliquescence are most preferable.
  • a thin film containing a metal oxide precursor is formed by applying and forming an aqueous solution containing a metal salt on a substrate.
  • a spray coating method As a method of forming a metal oxide precursor thin film by coating and forming an aqueous solution containing a metal salt on a substrate, a spray coating method, a spin coating method, a blade coating method, a dip coating method, a casting method, Examples include roll coating methods, bar coating methods, die coating methods, mist methods, printing methods such as relief printing, intaglio printing, lithographic printing, screen printing, and ink jet printing, and methods using coating in a broad sense. The method etc. are mentioned.
  • the coating film may be patterned by photolithography, laser ablation, or the like.
  • an ink jet method, a spray coating method, and the like that can be patterned by a droplet jetting method and can be applied with a thin film, and an ink jet method is particularly preferable.
  • a semiconductor precursor layer thin film containing a metal salt is formed by dropping a metal salt aqueous solution and volatilizing a solvent (water) at about 150 ° C.
  • a solvent water
  • the temperature (° C.) of the base material also referred to as a substrate
  • the temperature range of 50% to 150% of the boiling point (° C.) of the main solvent of the solution is adjusted to a temperature range of 50% to 150% of the boiling point (° C.) of the main solvent of the solution, and the solution is applied and formed into a film.
  • the thickness of the semiconductor precursor layer according to the present invention is preferably adjusted in the range of 1 nm to 200 nm, preferably 5 nm to 100 nm.
  • metal oxide semiconductor layer also referred to as metal oxide layer or metal oxide film
  • a method for manufacturing a metal oxide semiconductor layer (metal oxide layer) according to the present invention will be described.
  • a metal oxide layer (also referred to as a metal oxide film) according to the present invention can be obtained by oxidizing a metal ion (also referred to as a metal salt) contained in the metal oxide precursor thin film according to the present invention. .
  • the metal oxide semiconductor layer according to the present invention includes a metal oxide semiconductor obtained by oxidizing at least one of metal salts selected from nitrates, sulfates, phosphates, carbonates, acetates or oxalates. A layer is preferred.
  • Metal oxide semiconductor As the metal oxide semiconductor according to the present invention, any state of single crystal, polycrystal, and amorphous can be used, but an amorphous oxide is preferably used.
  • the electron carrier concentration of an amorphous oxide, which is a metal oxide according to the present invention, formed from a metal compound material that is a precursor of a metal oxide semiconductor only needs to be less than 10 18 / cm 3 .
  • the electron carrier concentration is a value measured at room temperature.
  • the room temperature is, for example, 25 ° C., specifically, a certain temperature appropriately selected from the range of about 0 ° C. to 40 ° C.
  • the electron carrier concentration of the amorphous oxide according to the present invention may not satisfy less than 10 18 / cm 3 in the entire range of 0 ° C. to 40 ° C.
  • a carrier electron density of less than 10 18 / cm 3 may be realized at 25 ° C. Further, when the electron carrier concentration is further reduced to 10 17 / cm 3 or less, more preferably 10 16 / cm 3 or less, a normally-off TFT can be obtained with a high yield.
  • the measurement of electron carrier concentration can be obtained by Hall effect measurement.
  • the film thickness of the semiconductor active layer containing a metal oxide semiconductor As the film thickness of the semiconductor active layer containing a metal oxide semiconductor, the characteristics of the obtained transistor are often greatly influenced by the film thickness of the metal oxide semiconductor layer, and the film thickness varies depending on the semiconductor. Generally, it is preferably 1 ⁇ m or less, particularly preferably 10 nm to 300 nm.
  • the precursor material metal salt
  • composition ratio production conditions, and the like
  • the electron carrier concentration is preferably 10 12 / cm 3 or more and less than 10 18 / cm 3. More preferably, it is 10 13 / cm 3 or more and 10 17 / cm 3 or less, and particularly preferably in the range of 10 15 / cm 3 or more and 10 16 / cm 3 or less.
  • Examples of a method for converting the semiconductor precursor layer formed from the metal inorganic salt into a metal oxide semiconductor layer by heat treatment include an oxidation treatment such as an oxygen plasma method, a thermal oxidation method, and a UV ozone method.
  • an oxidation treatment such as an oxygen plasma method, a thermal oxidation method, and a UV ozone method.
  • microwave irradiation described later can be exemplified.
  • thermal oxidation heat treatment is preferably performed in a temperature range of 100 ° C. to 400 ° C. It is more preferable to carry out in the presence of oxygen from the viewpoint of promoting the reaction.
  • the oxidation treatment can be performed at a relatively low temperature by using a metal salt selected from nitrate, sulfate, phosphate, carbonate, acetate or oxalate according to the present invention.
  • the formation of the metal oxide can be detected by XPS (X-ray photoelectron spectroscopy: also referred to as ESCA) and the conditions under which the conversion to the metal oxide semiconductor or the conductive material is sufficiently performed can be selected in advance.
  • XPS X-ray photoelectron spectroscopy: also referred to as ESCA
  • the substrate is preferably heated in the range of 50 ° C. to 300 ° C.
  • an inert gas such as argon gas is used as a discharge gas under atmospheric pressure, and a reaction gas (a gas containing oxygen) is introduced into the discharge space, and a high frequency electric field is applied to the discharge gas. Is excited to generate plasma, and contact with a reactive gas to generate plasma containing oxygen, and the substrate surface is exposed to this to perform oxygen plasma treatment.
  • a reaction gas a gas containing oxygen
  • oxygen plasma is generated as a reactive gas, oxygen plasma is generated, and the precursor thin film containing a metal salt is exposed to the plasma space, so that the precursor thin film is oxidized and decomposed by plasma oxidation. A layer made of a metal oxide is formed.
  • the high frequency power supply is 0.5 kHz or more and 2.45 GHz or less, and the power supplied between the counter electrodes is preferably adjusted to a range of 0.1 W / cm 2 or more and 50 W / cm 2 or less.
  • the gas used is basically a mixed gas of a discharge gas (inert gas) and a reaction gas (oxidizing gas).
  • the reaction gas is preferably oxygen gas, and is preferably contained in an amount of 0.01 to 10% by volume with respect to the mixed gas. It is more preferably 0.1% by volume to 10% by volume, and still more preferably 0.1% by volume to 5% by volume.
  • inert gas examples include Group 18 elements of the periodic table, specifically helium, neon, argon, krypton, xenon, radon, nitrogen gas, etc., in order to obtain the effects described in the present invention.
  • Helium, argon, and nitrogen gas are preferable.
  • normal temperature and normal pressure may be used to introduce the reaction gas between the electrodes which are the discharge space.
  • the UV ozone method is a method in which an oxidation reaction is advanced by irradiating ultraviolet light in the presence of oxygen. It is preferable to irradiate so-called vacuum ultraviolet light having a wavelength of ultraviolet light of about 100 nm to 450 nm, particularly preferably about 150 nm to 300 nm.
  • the light source may be a low-pressure mercury lamp, deuterium lamp, xenon excimer lamp, metal halide lamp, excimer laser, or the like.
  • the illuminance upon UV irradiation is preferably 1 mW to 10 W / cm 2 .
  • oxidation treatment it is preferable to perform heat treatment after the oxidation treatment or simultaneously with the oxidation treatment in addition to the oxidation treatment. Thereby, oxidation treatment can be promoted.
  • the substrate (also referred to as a base material) is in the range of 50 ° C. to 200 ° C., preferably 80 ° C. to 150 ° C.
  • the heating time is preferably 1 minute to 10 hours.
  • the heat treatment may be performed simultaneously with the oxidation treatment, and can be rapidly converted into a metal oxide semiconductor by oxidation.
  • the film thickness of the metal oxide semiconductor layer formed by oxidation treatment of metal ions is preferably 1 nm to 200 nm, more preferably 5 nm to 100 nm.
  • microwave irradiation microwave (0. 3 GHz to 50 GHz) is preferably used as a method for converting (oxidizing) a thin film formed from the metal inorganic salt material to be a semiconductor precursor (metal oxide precursor) into a metal oxide semiconductor.
  • microwave irradiation microwave (0. 3 GHz to 50 GHz) is preferably used as a method for converting (oxidizing) a thin film formed from the metal inorganic salt material to be a semiconductor precursor (metal oxide precursor) into a metal oxide semiconductor.
  • microwave irradiation microwave (0. 3 GHz to 50 GHz
  • the thin film is irradiated with electromagnetic waves, particularly microwaves (frequency 0.5 GHz to 50 GHz) in the presence of oxygen. Is preferred.
  • the thin film containing the metal salt material which is a precursor of the metal oxide semiconductor
  • the metal salt material which is a precursor of the metal oxide semiconductor
  • microwaves By irradiating the thin film containing the metal salt material, which is a precursor of the metal oxide semiconductor, with microwaves, electrons in the metal oxide precursor vibrate, Joule heat is generated, and the thin film is uniformly distributed from the inside. Heated. Since substrates such as glass and resin have almost no absorption in the microwave region, the substrate itself hardly generates heat, and only the thin film portion is selectively heated to be thermally oxidized, converted into a metal oxide semiconductor or a conductive material. It becomes possible.
  • microwave absorption concentrates on strongly absorbing substances and can be heated to 500 ° C. to 600 ° C. in a very short time.
  • the base material itself is hardly affected by heating by electromagnetic waves, and only the precursor thin film can be heated to the temperature at which the oxidation reaction takes place in a short time, and the metal oxide precursor is converted to metal oxide. It becomes possible to do.
  • the heating temperature and the heating time can be controlled by the output of the microwave to be irradiated and the irradiation time, and can be adjusted according to the precursor material and the substrate material.
  • a microwave refers to an electromagnetic wave having a frequency of 0.5 GHz to 50 GHz, and is used in 0.8 MHz and 1.5 GHz band, 2 GHz band, amateur radio, aircraft radar, etc. used in mobile communication. .2 GHz band, microwave oven, local radio, 2.4 GHz band used for VICS, 3 GHz band used for ship radar, etc., and 5.6 GHz used for other ETC communications are all electromagnetic waves in the microwave category. is there.
  • the precursor of the metal oxide semiconductor of the present invention can be selectively heated uniformly to a high temperature in a short time, similarly to ceramics.
  • the method of performing semiconductor conversion treatment by irradiating the semiconductor precursor layer containing the metal salt with microwaves is a method in which an oxidation reaction is selectively advanced in a short time.
  • the substrate can be controlled by controlling the microwave output, irradiation time, and the number of times of irradiation. It is preferable to perform the treatment so that the temperature is 50 ° C. to 200 ° C. and the surface temperature of the precursor-containing thin film is 200 ° C. to 600 ° C.
  • the temperature of the thin film surface, the temperature of the substrate, etc. can be measured with a surface thermometer using a thermocouple or a non-contact surface thermometer.
  • the metal oxide semiconductor thin film formed from the metal salt according to the present invention can be used in various devices, electronic circuits, etc., and is applied to a metal oxide in a low temperature process by applying an aqueous solution of a precursor material on a substrate.
  • a physical semiconductor material layer can be produced, and can be preferably applied to the manufacture of an electronic device using a resin substrate, especially a thin film transistor (TFT).
  • TFT thin film transistor
  • the conductive material used for the electrodes such as the source electrode, the drain electrode, and the gate electrode constituting the thin film transistor is not particularly limited as long as it has conductivity at a practical level as an electrode.
  • Fluorine-doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste and carbon paste lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium, manganese, zirconium, gallium, niobium, sodium Beam, sodium - potassium alloy, magnesium, lithium, aluminum, magnesium / copper mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, magnesium /
  • a metal material selected from the group consisting of tantalum, aluminum, titanium, niobium, neodymium, zirconium, hafnium, chromium, molybdenum and alloys thereof as the metal material constituting the gate electrode of the present invention.
  • the gate electrode according to the present invention may be composed of only the above metal material.
  • the gate electrode is composed of at least two layers of a metal oxide conductive layer and a metal layer containing a metal material from the substrate side. The structure which becomes can be mentioned.
  • the gate insulating film can be formed by anodizing the metal layer.
  • Metal oxide conductive layer (Metal oxide conductive layer) The metal oxide conductive layer according to the present invention will be described.
  • the metal oxide conductive layer according to the present invention is preferably composed of a metal oxide conductor such as ITO, ZnO, or SnO 2 capable of absorbing the above microwaves.
  • the metal oxide conductive layer generates heat by irradiating the above microwave irradiation from the back side of the substrate having the semiconductor precursor layer, and the semiconductor precursor layer is efficiently applied to the metal oxide semiconductor layer. It becomes possible to convert.
  • Electrode forming method a conductive thin film formed using a method such as vapor deposition or sputtering, a method of forming an electrode using a known photolithographic method or a lift-off method, thermal transfer onto a metal foil such as aluminum or copper, There is a method of forming and etching a resist by ink jet or the like.
  • a conductive polymer solution or dispersion, a dispersion containing metal fine particles, or the like may be directly patterned by an ink jet method, or may be formed from a coating film by lithography or laser ablation.
  • a method of patterning a conductive ink or conductive paste containing a conductive polymer or metal fine particles by a printing method such as relief printing, intaglio printing, planographic printing or screen printing can also be used.
  • An electroless plating method is known as a method for forming an electrode such as a source, drain or gate electrode, or a gate or source bus line without patterning a metal thin film using a photosensitive resin such as etching or lift-off. It has been.
  • the portion where the electrode is provided contains a plating catalyst that causes electroless plating by acting with a plating agent.
  • a plating agent is brought into contact with a portion where an electrode is provided. If it does so, electroless plating will be performed to the said part by the contact of the said catalyst and a plating agent, and an electrode pattern will be formed.
  • the application of the electroless plating catalyst and the plating agent may be reversed, and the pattern formation may be performed either.
  • a method of forming a plating catalyst pattern and applying the plating agent to this is preferable.
  • the printing method for example, screen printing, planographic printing, letterpress printing, intaglio printing, printing by ink jet printing, or the like is used.
  • Inorganic oxide films include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Examples thereof include barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide.
  • silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable.
  • the gate insulating film (layer) is preferably composed of an anodized film or the anodized film and an insulating film.
  • anodizing not only a gate insulating film having a good insulating property at a low temperature can be obtained, but also a projection due to metal migration can be smoothed, and a good semiconductor interface can be formed.
  • the anodized film is preferably sealed.
  • the anodized film is formed by anodizing a metal that can be anodized by a known method.
  • Examples of the metal that can be anodized include aluminum and tantalum, and the anodizing method is not particularly limited, and a known method can be used.
  • An inorganic oxide film and an organic oxide film can be laminated and used together.
  • the thickness of these insulating films is generally 50 nm to 3 ⁇ m, preferably 100 nm to 1 ⁇ m.
  • the support material constituting the substrate Various materials can be used as the support material constituting the substrate.
  • ceramic substrates such as glass, quartz, aluminum oxide, sapphire, silicon nitride, silicon carbide, silicon, germanium, gallium arsenide, gallium phosphide.
  • a semiconductor substrate such as gallium nitrogen, paper, and non-woven fabric can be used.
  • the support is preferably made of a resin, for example, a plastic film sheet can be used.
  • plastic films examples include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose.
  • PET polyethylene terephthalate
  • PEN polyethylene naphthalate
  • PES polyethersulfone
  • CAP cellulose acetate propionate
  • the weight can be reduced as compared with the case of using a glass substrate, the portability can be improved, and the resistance to impact can be improved.
  • the protective layer includes the inorganic oxides and inorganic nitrides described above, and it is preferable to form the protective layer by the atmospheric pressure plasma method described above.
  • FIG. 1 is a schematic sectional view showing a manufacturing process of the thin film transistor element 1 of the present invention.
  • a Ta thin film (250 nm) was formed by sputtering on a glass substrate 1 (thickness 0.5 mm) to produce a substrate having a metal gate electrode 2 (also referred to as Ta gate electrode) (FIGS. 1A and 1B). ).
  • the metal gate electrode 2 was used as an anode, platinum was used as a cathode, connected to a constant current voltage power source, then immersed in a 1% phosphoric acid aqueous solution, and a voltage was applied so that a constant current of 0.2 mA / cm 2 was obtained. .
  • a gate insulating film 3 also referred to as a Ta 2 O 3 gate insulating film
  • the source electrode 6 and the drain electrode 7 were formed by vapor deposition using gold, and the thin film transistor element 1 was manufactured.
  • the current at the time of Off was 10 ⁇ 12 or less, and good insulation was shown.
  • FIG. 2 is a schematic sectional view showing a manufacturing process of the thin film transistor element 2 of the present invention.
  • a gate insulating film 13 also referred to as an Al 2 O 3 gate insulating film
  • a polysilazane solution (NN110: manufactured by AZ Electronic Materials) was applied on the gate insulating film 13 so that the film thickness after the conversion treatment was 15 nm, thereby forming a polysilazane thin film 14 (FIG. 2D).
  • the obtained polysilazane thin film 14 was dried at 150 ° C. for 10 minutes, and then subjected to 30 conditions under the conditions of a flow rate of 0.6 L / min and a substrate temperature of 200 ° C. using a UV ozone irradiator (UV-1: manufactured by Samco). UV ozone irradiation treatment 15 was performed for a minute, and the polysilazane thin film 14 was converted into an insulating film 16 containing silicon oxide (FIG. 2E).
  • UV ozone irradiator UV-1: manufactured by Samco
  • a semiconductor precursor layer 17 was formed on the gate insulating film 13 (also referred to as an anodic oxide film) by an inkjet method (FIG. 2F).
  • the glass substrate 20 with the ITO layer 19 is disposed on the back side of the glass substrate 11 so that the substrate glass and ITO are in contact with each other, and 2.45 GHz microwaves 21 are maintained from the back side while maintaining the temperature of the glass substrate 11 at 200 ° C.
  • a metal oxide semiconductor layer 18 For 15 minutes to form a metal oxide semiconductor layer 18 (FIG. 2G).
  • the source electrode 22 and the drain electrode 23 were formed by vapor deposition using gold to manufacture the thin film transistor element 2.
  • the current at the time of Off was 10 ⁇ 12 or less, and good insulation was shown.
  • FIG. 3 is a schematic sectional view showing a manufacturing process of the thin film transistor element 3 of the present invention.
  • An ITO thin film line pattern 22 was formed on the glass substrate 31 by sputtering, and then a Ta metal film pattern 33 (also referred to as a metal gate electrode) having a width wider than the ITO line width was formed immediately above the ITO thin film pattern 32. (FIG. 3 (a), (b)).
  • the gate insulating film 34 was formed by anodic oxidation in the same manner as in Example 1, and then the metal oxide semiconductor precursor layer 35 was formed by coating (FIGS. 3C and 3D).
  • the microwave 36 of 2.45 GHz was irradiated from the back side of the glass substrate 31 at a temperature of the glass substrate 31 of 300 ° C. for 15 minutes to form the metal oxide semiconductor layer 35.
  • a thin film transistor element 3 was fabricated by forming a source electrode 37 and a drain electrode 38 by vapor deposition so as to partially cover the metal oxide semiconductor layer 35.
  • Example 4 Manufacture of Thin Film Transistor Element 4 >> In the manufacture of the thin film transistor element 3 described in Example 3, the thin film transistor element 4 was manufactured in the same manner except that a polyimide substrate (a polyimide substrate having a film thickness of 200 ⁇ m) was used instead of the glass substrate 31.
  • a polyimide substrate a polyimide substrate having a film thickness of 200 ⁇ m
  • the current at the time of Off was 10 ⁇ 12 or less, and good insulation was shown.

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Abstract

Disclosed is a method for manufacturing a thin film transistor that exhibits high gain transistor characteristics, wherein a gate insulating film having good insulation performance (high insulation strength) is formed on the surface of a gate electrode and the thus-formed gate insulating film is combined with a metal oxide semiconductor layer.

Description

薄膜トランジスタの製造方法及び薄膜トランジスタThin film transistor manufacturing method and thin film transistor
　本発明は、薄膜トランジスタの製造方法及び薄膜トランジスタに係る。 The present invention relates to a thin film transistor manufacturing method and a thin film transistor.
　ゲート電極の表面を陽極酸化して形成された、欠陥の少ない金属酸化膜をゲート絶縁層として有する有機薄膜トランジスタが開示されており（例えば、特許文献３及び４参照。）、また、ゲート電極上にゲート電極材の酸化物からなるゲート酸化膜と、有機化合物からなるゲート絶縁層とを有し、耐圧特性が改善された有機薄膜トランジスタが開示されている（例えば、特許文献５参照。）。 An organic thin film transistor having a metal oxide film with few defects formed by anodizing the surface of a gate electrode as a gate insulating layer is disclosed (for example, see Patent Documents 3 and 4). An organic thin film transistor having a gate oxide film made of an oxide of a gate electrode material and a gate insulating layer made of an organic compound and improved withstand voltage characteristics is disclosed (for example, refer to Patent Document 5).
　更に、ゲート電極を形成する金属層に熱酸化処理（３００℃～６００℃の温度条件）を施し、前記ゲート電極の表面にゲート絶縁層を形成させるもの（例えば、特許文献６参照。）や、ゲート電極の表面を陽極酸化することにより、該ゲート電極の表面上にゲート絶縁層を有し、且つ、亜鉛インジウム酸化物（ＩＺＯ）系の金属酸化物半導体層を有する薄膜トランジスタ（例えば、特許文献７参照。）等が知られている。 Further, a metal layer that forms the gate electrode is subjected to a thermal oxidation treatment (temperature condition of 300 ° C. to 600 ° C.) to form a gate insulating layer on the surface of the gate electrode (see, for example, Patent Document 6). By anodizing the surface of the gate electrode, a thin film transistor having a gate insulating layer on the surface of the gate electrode and a zinc indium oxide (IZO) -based metal oxide semiconductor layer (for example, Patent Document 7) Etc.) are known.
　しかしながら、有機薄膜トランジスタは、電子機器に求められる繰り返し耐久性が課題であり使用できる機器が制限されてしまう欠点がある。また、熱酸化処理による酸化膜形成では非常に高い温度にさらされるため、昨今、求められている樹脂基板への適用が難しく、無機酸化物半導体を用いた例では、プロセス温度は低いものの巣半導体成膜に真空系のスパッタ法を用いており、せっかくフレキシブルな樹脂基板を適用できても、いわゆるロール・トゥ・ロールのような効率的な生産をすることができないという問題点があった。 However, organic thin film transistors have a drawback in that the durability required for electronic devices is a problem, and the devices that can be used are limited. In addition, since oxide film formation by thermal oxidation treatment is exposed to extremely high temperatures, it is difficult to apply to resin substrates that are now required, and in the case of using an inorganic oxide semiconductor, the nest semiconductor has a low process temperature. A vacuum-type sputtering method is used for film formation, and even if a flexible resin substrate can be applied, there is a problem that efficient production such as so-called roll-to-roll cannot be performed.
　一方、金属塩や有機金属を分解酸化（加熱、分解反応）することで、非晶質酸化物半導体を形成する方法が知られている。 On the other hand, a method of forming an amorphous oxide semiconductor by decomposing and oxidizing (heating, decomposition reaction) a metal salt or an organic metal is known.
　非晶質酸化物半導体を形成する手段として、有機金属を分解酸化（加熱、分解反応）する工程を経て形成する方法が開示されている（例えば、特許文献１及び２参照。）。 As a means for forming an amorphous oxide semiconductor, a method of forming an organic metal through a process of decomposing and oxidizing (heating, decomposition reaction) is disclosed (for example, see Patent Documents 1 and 2).
　これらにおいては、前駆体の酸化に、熱酸化または、プラズマ酸化を用いている。しかしながら、前駆体の酸化に熱酸化法を用いる場合、最低３００℃以上、実質５５０℃以上の非常に高い温度域で処理しないと求める性能達成は通常は難しい。 In these, thermal oxidation or plasma oxidation is used for the oxidation of the precursor. However, when the thermal oxidation method is used to oxidize the precursor, it is usually difficult to achieve the required performance unless the treatment is performed at a very high temperature range of 300 ° C. or higher and substantially 550 ° C. or higher.
　従って、エネルギー効率が悪く、比較的長い処理時間を要してしまうことや、処理中の基板温度も処理温度と同じ温度まで上昇するため、軽く、フレキシビリティを有する樹脂基板などへの適用が困難となる。 Therefore, it is not energy efficient, requires a relatively long processing time, and the substrate temperature during processing rises to the same temperature as the processing temperature, making it difficult to apply to light and flexible resin substrates. It becomes.
　また、プラズマ酸化の場合には、非常に反応性の高いプラズマ空間で処理を行うために、薄膜トランジスタの製造プロセスにおいては、電極や絶縁膜などを劣化させ、移動度やｏｆｆ電流（暗電流）が悪化する等の問題を引き起こしてしまう。 In the case of plasma oxidation, since processing is performed in a very reactive plasma space, in the thin film transistor manufacturing process, electrodes and insulating films are deteriorated, and mobility and off current (dark current) are reduced. It will cause problems such as deterioration.
　また、前駆体として、有機金属や金属塩化物を用い熱酸化等により非晶質酸化物半導体を形成することも知られている（例えば、非特許文献１、２及び３参照）。 It is also known that an amorphous oxide semiconductor is formed by thermal oxidation or the like using an organic metal or metal chloride as a precursor (see, for example, Non-Patent Documents 1, 2, and 3).
　例えば金属アルコキシドを前駆体として用いる場合、高温処理が必要であるほかに残留カーボンによる性能劣化があり、また、前駆体として塩化物を用いる場合には、ハロゲン排出の問題を抱えている。また、これらの前駆体においては、水に対し分解性を有することから有機溶媒中に溶解させる場合が多く製造環境上にも問題点があった。 For example, when metal alkoxide is used as a precursor, high temperature treatment is required, and there is a performance deterioration due to residual carbon. When chloride is used as a precursor, there is a problem of halogen emission. Moreover, these precursors are often decomposable with respect to water, so that they are often dissolved in an organic solvent and have problems in the production environment.
特開２００３－１７９２４２号公報JP 2003-179242 A 特開２００５－２２３２３１号公報Japanese Patent Laid-Open No. 2005-223231 特開２００３－２５８２６０号公報JP 2003-258260 A 特開２００３－２５８２６１号公報JP 2003-258261 A 特開２００４－２３５２９８号公報JP 2004-235298 A 米国特許出願公開第２００６／０００３４８５号明細書US Patent Application Publication No. 2006/0003485 米国特許第７４２７７７６号明細書US Pat. No. 7,427,776
　本発明の目的は、低温かつ大気圧下で製造可能であり、絶縁性の良好な（絶縁強度が高い）ゲート絶縁層、また、半導体層を提供することにより、プラスチック基材のような耐熱性が低い基材にも形成可能で、ロール・トゥ・ロールのような連続性生産性に優れ、高性能かつ低コストで製造可能な薄膜トランジスタの製造方法を提供することである。 An object of the present invention is to provide a gate insulating layer that can be manufactured at a low temperature and under atmospheric pressure and has good insulating properties (high insulating strength), and a semiconductor layer. It is an object of the present invention to provide a method for producing a thin film transistor that can be formed on a low substrate, has excellent continuity productivity such as roll-to-roll, and can be produced at high performance and at low cost.
　本発明の目的は下記の構成により達成された。 The object of the present invention has been achieved by the following constitution.
　１．基板上に、ゲート電極、ゲート絶縁膜、金属酸化物半導体層、ソース電極及びドレイン電極を有する薄膜トランジスタの製造方法において、
　該ゲート絶縁膜が金属酸化膜であり、該ゲート電極の表面を陽極酸化することにより、前記ゲート電極の表面上に該金属酸化膜を形成する工程を有することを特徴とする薄膜トランジスタの製造方法。 1. In a method for manufacturing a thin film transistor having a gate electrode, a gate insulating film, a metal oxide semiconductor layer, a source electrode, and a drain electrode on a substrate,
A method of manufacturing a thin film transistor, comprising: forming a metal oxide film on a surface of the gate electrode by anodizing the surface of the gate electrode, wherein the gate insulating film is a metal oxide film.
　２．前記ゲート電極が、タンタル、アルミニウム、チタン、ニオブ、ジルコニウム、ハフニウム、ネオジウム、クロム、モリブデン及びモリブデン－タンタル合金からなる群から選択された金属材料を含有することを特徴とする前記１に記載の薄膜トランジスタの製造方法。 2. 2. The thin film transistor according to 1 above, wherein the gate electrode contains a metal material selected from the group consisting of tantalum, aluminum, titanium, niobium, zirconium, hafnium, neodymium, chromium, molybdenum, and molybdenum-tantalum alloy. Manufacturing method.
　３．前記ゲート絶縁膜の少なくとも一部に、溶液塗布法により半導体前駆体層を形成し、該半導体前駆体層を酸化変換して金属酸化物半導体層を形成する工程を有することを特徴とする前記１または２に記載の薄膜トランジスタの製造方法。 3. The method of claim 1, further comprising: forming a semiconductor precursor layer on at least a part of the gate insulating film by a solution coating method, and oxidizing the semiconductor precursor layer to form a metal oxide semiconductor layer. Or a method for producing the thin film transistor according to 2;
　４．前記ゲート絶縁膜上の少なくとも一部に、溶液塗布法により酸化シリコン前駆体層を形成し、酸化変換して酸化シリコンを含む絶縁層を形成した後、酸化シリコンを含む絶縁層上に溶液塗布法により半導体前駆体層を形成し、該半導体前駆体層を酸化変換して金属酸化物半導体層を形成する工程を有することを特徴とする前記１または２に記載の薄膜トランジスタの製造方法。 4. A silicon oxide precursor layer is formed on at least a part of the gate insulating film by a solution coating method, an oxidation conversion is performed to form an insulating layer containing silicon oxide, and then a solution coating method is performed on the insulating layer containing silicon oxide. 3. The method for producing a thin film transistor according to 1 or 2 above, comprising the steps of: forming a semiconductor precursor layer by oxidation, and oxidizing the semiconductor precursor layer to form a metal oxide semiconductor layer.
　５．前記金属酸化物半導体層が、少なくともＩｎ、ＺｎまたはＳｎのいずれか１つを含むことを特徴とする前記１～４のいずれか１項に記載の薄膜トランジスタの製造方法。 5. 5. The method of manufacturing a thin film transistor according to any one of 1 to 4, wherein the metal oxide semiconductor layer contains at least one of In, Zn, or Sn.
　６．前記金属酸化物半導体層が、少なくともＧａ、Ａｌのいずれか１つを含むことを特徴とする前記１～５のいずれか１項に記載の薄膜トランジスタの製造方法。 6. 6. The method for manufacturing a thin film transistor according to any one of 1 to 5, wherein the metal oxide semiconductor layer contains at least one of Ga and Al.
　７．前記半導体前駆体層の酸化変換が１００℃～４００℃の温度範囲における熱処理であることを特徴とする前記１～６のいずれか１項に記載の薄膜トランジスタの製造方法。 7. 7. The method of manufacturing a thin film transistor according to any one of 1 to 6, wherein the oxidation conversion of the semiconductor precursor layer is a heat treatment in a temperature range of 100 ° C. to 400 ° C.
　８．前記半導体前駆体層が金属塩を含む水を主成分とした溶液を塗布法により、ゲート絶縁膜の表面の一部に形成される工程を有することを特徴とする前記１～７のいずれか１項に記載の薄膜トランジスタの製造方法。 8. Any one of the above 1 to 7, wherein the semiconductor precursor layer has a step of forming a solution containing water containing a metal salt as a main component on a part of the surface of the gate insulating film by a coating method. The manufacturing method of the thin-film transistor as described in a term.
　９．前記金属塩が金属硝酸塩を含むことを特徴とする前記８に記載の薄膜トランジスタの製造方法。 9. 9. The method of manufacturing a thin film transistor according to 8 above, wherein the metal salt includes a metal nitrate.
　１０．前記ゲート電極が、基板側から金属酸化物導電層、金属材料を含有する金属層の少なくとも２層からなり、該金属層を陽極酸化することによりゲート絶縁膜が形成されることを特徴とする前記１～９のいずれか１項に記載の薄膜トランジスタの製造方法。 10. The gate electrode is composed of at least two layers of a metal oxide conductive layer and a metal layer containing a metal material from the substrate side, and a gate insulating film is formed by anodizing the metal layer. 10. The method for producing a thin film transistor according to any one of 1 to 9.
　１１．前記半導体前駆体層を酸化変換して金属酸化物半導体層に変換する工程にマイクロ波（０．３ＧＨｚ～５０ＧＨｚ）を照射することを特徴とする前記３～１０のいずれか１項に記載の薄膜トランジスタの製造方法。 11. 11. The thin film transistor according to any one of 3 to 10, wherein a microwave (0.3 GHz to 50 GHz) is irradiated to the step of converting the semiconductor precursor layer into a metal oxide semiconductor layer by oxidation conversion Manufacturing method.
　１２．前記マイクロ波の照射を、半導体前駆体層を有する基板の裏面側から照射し、前記金属酸化物導電層が発熱し、前記半導体前駆体層を金属酸化物半導体層に変換する工程を有することを特徴とする前記１１に記載の薄膜トランジスタの製造方法。 12. The step of irradiating the microwave from the back side of the substrate having a semiconductor precursor layer, the metal oxide conductive layer generating heat, and converting the semiconductor precursor layer into a metal oxide semiconductor layer. 12. The method for producing a thin film transistor according to 11 above.
　１３．前記１～１２のいずれか１項に記載の薄膜トランジスタの製造方法により製造されたことを特徴とする薄膜トランジスタ。 13. 13. A thin film transistor manufactured by the method for manufacturing a thin film transistor according to any one of 1 to 12 above.
　本発明により、低温かつ常圧下で、ゲート電極の表面に絶縁性の良好な（絶縁強度が高い）ゲート絶縁膜を形成し、得られたゲート絶縁層と低温かつ常圧下で形成可能な塗布型金属酸化物半導体層とを組み合わせることにより、生産性に優れ、低コストで製造できかつ高ゲインのトランジスタ特性を示す薄膜トランジスタの製造方法を提供できることが分かった。 According to the present invention, a gate insulating film having good insulation (high insulation strength) is formed on the surface of the gate electrode at a low temperature and under a normal pressure, and the resulting gate insulating layer can be formed at a low temperature and under a normal pressure. It has been found that by combining with a metal oxide semiconductor layer, a method for manufacturing a thin film transistor that is excellent in productivity, can be manufactured at low cost, and exhibits high gain transistor characteristics can be provided.
本発明の薄膜トランジスタ素子の製造工程の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the manufacturing process of the thin-film transistor element of this invention. 本発明の薄膜トランジスタ素子の製造工程の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the manufacturing process of the thin-film transistor element of this invention. 本発明の薄膜トランジスタ素子の製造工程の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the manufacturing process of the thin-film transistor element of this invention.
　本発明の薄膜トランジスタの製造方法においては、請求項１～１２のいずれか１項に規定の構成を有することにより、低温かつ常圧下でゲート電極の表面に絶縁性の良好な（絶縁強度が高い）ゲート絶縁膜を形成し、得られたゲート絶縁層と、低温かつ常圧下で塗布型金属酸化物半導体層とを組み合わせることにより、プラスチック基板上にも形成可能であり、生産性に優れた高ゲインのトランジスタ特性を示す薄膜トランジスタの製造方法を提供することができた。 In the method for manufacturing a thin film transistor of the present invention, by having the structure defined in any one of claims 1 to 12, the surface of the gate electrode has good insulation (high insulation strength) at low temperature and normal pressure. By forming a gate insulating film and combining the resulting gate insulating layer with a coating-type metal oxide semiconductor layer at low temperature and normal pressure, it can be formed on a plastic substrate and has high gain with excellent productivity. It was possible to provide a method for manufacturing a thin film transistor exhibiting the above transistor characteristics.
　以下本発明を実施するための最良の形態について説明するが、本発明はこれらにより限定されない。 Hereinafter, the best mode for carrying out the present invention will be described, but the present invention is not limited thereto.
　《薄膜トランジスタの製造方法》
　本発明の薄膜トランジスタの製造方法について説明する。 << Thin Film Transistor Manufacturing Method >>
A method for manufacturing the thin film transistor of the present invention will be described.
　本発明の薄膜トランジスタの製造方法は、請求項１に記載のように、基板上に、ゲート電極、ゲート絶縁膜、金属酸化物半導体層、ソース電極及びドレイン電極を有する薄膜トランジスタの製造方法において、ゲート絶縁膜が金属酸化膜であり、ゲート電極の表面を陽極酸化することにより、ゲート電極の表面上に該金属酸化膜を形成する工程を有することにより、ゲート電極の表面に絶縁性の良好な（絶縁強度が高い）ゲート絶縁膜を形成し、得られたゲート絶縁膜と金属酸化物半導体層とを組み合わせることにより、高ゲインのトランジスタ特性を示す薄膜トランジスタの製造方法を得るものである。 The method of manufacturing a thin film transistor according to the present invention is the method of manufacturing a thin film transistor having a gate electrode, a gate insulating film, a metal oxide semiconductor layer, a source electrode and a drain electrode on a substrate. The film is a metal oxide film, and the step of forming the metal oxide film on the surface of the gate electrode by anodizing the surface of the gate electrode has a good insulating property on the surface of the gate electrode (insulation A method for manufacturing a thin film transistor exhibiting high gain transistor characteristics is obtained by forming a gate insulating film having high strength and combining the obtained gate insulating film and a metal oxide semiconductor layer.
　《陽極酸化方法によるゲート絶縁膜の形成》
　本発明に係る陽極酸化方法によるゲート絶縁膜の形成について説明する。 << Formation of gate insulating film by anodic oxidation method >>
The formation of the gate insulating film by the anodic oxidation method according to the present invention will be described.
　本発明に係る陽極酸化方法としては、特開２００７－２１４５２５号公報に記載の酸素プラズマ工程を利用して陽極酸化する方法や、特開２００３－２５８２６０号公報、特開２００３－２５８２６１号公報等に記載の湿式の陽極酸化方法（電気化学的な陽極酸化方法ともいう）を用いることができるが、絶縁性の良好（絶縁強度）が高いゲート絶縁膜を得る観点からは、湿式の陽極酸化方法（電気化学的な陽極酸化方法）が好ましい。 Examples of the anodic oxidation method according to the present invention include a method of anodizing using an oxygen plasma process described in JP 2007-214525 A, JP 2003-258260 A, JP 2003-258261 A, and the like. The wet anodic oxidation method described (also referred to as electrochemical anodic oxidation method) can be used. From the viewpoint of obtaining a gate insulating film with good insulation (insulation strength), a wet anodic oxidation method ( The electrochemical anodizing method is preferred.
　電気化学的な陽極酸化法は低温で形成可能、高誘電率かつ高品位なゲート絶縁膜が形成可能であり、これと低温成膜する酸化物半導体と組み合わせることにより、耐熱性は低いが、反面、フレキシビリティの高いプラスチック等を基板として有し、トランジスタ特性の良好な薄膜トランジスタを提供することができる。 The electrochemical anodic oxidation method can be formed at low temperature, and can form a high dielectric constant and high-quality gate insulating film. By combining this with an oxide semiconductor film formed at a low temperature, the heat resistance is low. In addition, a thin film transistor which has a flexible plastic or the like as a substrate and has favorable transistor characteristics can be provided.
　本発明で好ましく用いられる電気化学的な陽極酸化方法の好ましい条件としては、ゲート電極として用いられる金属層の表面に形成される金属酸化膜（金属酸下層ともいう）の電圧が５０Ｖ～２００Ｖの範囲に上昇した時点で、前記電圧の印加を１分～１２０分の範囲で継続して、４０ｎｍ～５００ｎｍ（好ましくは、１００ｎｍ～２５０ｎｍ、更に好ましくは１００ｎｍ～１５０ｎｍの範囲である）の範囲でゲート絶縁層の膜厚を調整することが好ましい。 As a preferable condition of the electrochemical anodic oxidation method preferably used in the present invention, the voltage of a metal oxide film (also referred to as a metal acid underlayer) formed on the surface of a metal layer used as a gate electrode is in the range of 50V to 200V. When the voltage rises, the voltage application is continued for 1 minute to 120 minutes, and gate insulation is performed in the range of 40 nm to 500 nm (preferably in the range of 100 nm to 250 nm, more preferably in the range of 100 nm to 150 nm). It is preferable to adjust the thickness of the layer.
　また、形成された陽極酸化方法によるゲート絶縁膜は、封孔処理を行うことがより好ましい。陽極酸化膜は形成時には多孔質であるが、封孔処理を行うことにより、表面の孔を塞ぎ、平滑性の高い絶縁膜を形成することができる。 Further, it is more preferable that the formed gate insulating film is subjected to a sealing treatment. The anodized film is porous at the time of formation, but by performing sealing treatment, it is possible to close the surface holes and form an insulating film with high smoothness.
　また、陽極酸化膜には表面にバッファー層を設けることがより好ましい。 It is more preferable to provide a buffer layer on the surface of the anodic oxide film.
　理由は定かではないが、陽極酸化膜には表面にバッファー層を設けることにより、接着性が高く、かつ絶縁性の高いゲート絶縁膜を形成することができると推測される。また、酸化物半導体層とゲート絶縁膜との良好な界面形成ができ、電導度が向上すると考えられる。 The reason is not clear, but it is presumed that by providing a buffer layer on the surface of the anodized film, a highly insulating and highly insulating gate insulating film can be formed. In addition, it is considered that a favorable interface can be formed between the oxide semiconductor layer and the gate insulating film, and conductivity is improved.
　バッファー層材料としては特に限定されないが、種々の半導体材料と良好な界面形成が可能であるＳｉＯ２が好ましい。 No particular limitation is imposed on the buffer layer material, but, SiO 2 is preferably capable of good interface formation and various semiconductor materials.
　バッファー層の成膜方法としては、ＣＶＤ、スパッタ等、特に制限するところではないが、本発明では、大気圧下で連続成膜可能であり、かつ３００℃以下、好ましくは２００℃以下の低温で成膜可能である事が好ましい。 The method for forming the buffer layer is not particularly limited, such as CVD and sputtering, but in the present invention, continuous film formation is possible under atmospheric pressure, and at a low temperature of 300 ° C. or lower, preferably 200 ° C. or lower. It is preferable that a film can be formed.
　具体的な方法として、例えばペルヒドロポリシラザン溶液を塗布し、２００℃以下の温度で１２０ｎｍ～３００ｎｍの紫外光を照射してＳｉＯ２を形成する方法が挙げられるバッファー層の膜厚に特に制限はないが、１０ｎｍ～１００ｎｍの範囲が好ましい。 As a specific method, there is no particular limitation on the film thickness of the buffer layer, for example, a method of forming a SiO 2 by applying a perhydropolysilazane solution and irradiating ultraviolet light of 120 nm to 300 nm at a temperature of 200 ° C. or less. Is preferably in the range of 10 nm to 100 nm.
　また、本発明に係るゲート絶縁膜を構成する金属酸化膜としては、後述するゲート電極として用いられる金属材料である、タンタル、アルミニウム、チタン、ニオブ、ジルコニウム、ハフニウム、クロム、モリブデン及びモリブデン－タンタル合金から形成される金属材料群から選択される金属材料の酸化物から構成されることが好ましい。 Further, as the metal oxide film constituting the gate insulating film according to the present invention, tantalum, aluminum, titanium, niobium, zirconium, hafnium, chromium, molybdenum, and molybdenum-tantalum alloy, which are metal materials used as a gate electrode to be described later It is preferable that it is comprised from the oxide of the metal material selected from the metal material group formed from.
　次いで、本発明に係る金属酸化物半導体層の形成方法について説明する。 Next, a method for forming a metal oxide semiconductor layer according to the present invention will be described.
　本発明に係る金属酸化物半導体層は、半導体前駆体層（金属酸化物前駆体薄膜ともいう）を形成し、次いで、前記半導体前駆体層を焼成等の手段により金属酸化物半導体層に変換する工程を経て形成されることが好ましい。 The metal oxide semiconductor layer according to the present invention forms a semiconductor precursor layer (also referred to as a metal oxide precursor thin film), and then converts the semiconductor precursor layer into a metal oxide semiconductor layer by means such as baking. It is preferably formed through a process.
　《半導体前駆体層（金属酸化物前駆体薄膜）の作製方法》
　本発明において、金属酸化物前駆体薄膜を形成するためには、硝酸塩、硫酸塩、燐酸塩、炭酸塩、酢酸塩または蓚酸塩から選ばれる金属塩を適切な溶媒に溶解した溶液を用い基板上に連続的に塗設することが好ましく、生産性を大幅に向上させることができる。 << Method for Fabricating Semiconductor Precursor Layer (Metal Oxide Precursor Thin Film) >>
In the present invention, in order to form a metal oxide precursor thin film, a solution obtained by dissolving a metal salt selected from nitrate, sulfate, phosphate, carbonate, acetate or oxalate in an appropriate solvent is used on a substrate. It is preferable to coat continuously, and productivity can be improved significantly.
　金属塩における金属としては、Ｌｉ、Ｂｅ、Ｂ、Ｎａ、Ｍｇ、Ａｌ、Ｓｉ、Ｋ、Ｃａ、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｇａ、Ｇｅ、Ｒｂ、Ｓｒ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ｃｄ、Ｉｎ、Ｉｒ、Ｓｎ、Ｓｂ、Ｃｓ、Ｂａ、Ｌａ、Ｈｆ、Ｔａ、Ｗ、Ｔｌ、Ｐｂ、Ｂｉ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ等を挙げることができる。 As the metal in the metal salt, Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Rb , Sr, Y, Zr, Nb, Mo, Cd, In, Ir, Sn, Sb, Cs, Ba, La, Hf, Ta, W, Tl, Pb, Bi, Ce, Pr, Nd, Pm, Eu, Gd , Tb, Dy, Ho, Er, Tm, Yb, Lu and the like.
　本発明において、これらの金属塩においては、インジウム（Ｉｎ）、錫（Ｓｎ）、亜鉛（Ｚｎ）のいずれかの塩を１つ以上を含むことが好ましく、それらを併用して混合させてもよい。 In the present invention, these metal salts preferably contain one or more of any of indium (In), tin (Sn), and zinc (Zn), and may be used in combination. .
　また、その他の金属として、ガリウム（Ｇａ）またはアルミニウム（Ａｌ）のいずれかの塩を含むことが好ましい。 Moreover, it is preferable that the other metal contains a salt of either gallium (Ga) or aluminum (Al).
　（金属の組成比）
　本発明の方法により、前述した金属原子から選ばれた単独、または複数の金属原子を含む金属酸化物半導体の薄膜を作製する。金属酸化物半導体としては、単結晶、多結晶、非晶質のいずれの状態も使用可能だが、好ましくは非晶質の薄膜を用いる。 (Composition ratio of metal)
By the method of the present invention, a metal oxide semiconductor thin film containing a single metal atom or a plurality of metal atoms selected from the metal atoms described above is produced. As the metal oxide semiconductor, any state of single crystal, polycrystal, and amorphous can be used, but an amorphous thin film is preferably used.
　好ましい金属の組成比としては、Ｉｎ、Ｓｎの金属塩から選ばれる塩に含有される金属（金属Ａ）と、Ｇａ、Ａｌの金属塩から選ばれる塩に含有される金属（金属Ｂ）と、Ｚｎの金属塩に含有される金属（金属Ｃ＝Ｚｎ）とのモル比率（金属Ａ：金属Ｂ：金属Ｃ）が、以下の関係式を満たすことが好ましい。 As a preferred metal composition ratio, a metal (metal A) contained in a salt selected from metal salts of In and Sn, a metal (metal B) contained in a salt selected from metal salts of Ga and Al, and It is preferable that the molar ratio (metal A: metal B: metal C) with the metal (metal C = Zn) contained in the metal salt of Zn satisfies the following relational expression.
　金属Ａ：金属Ｂ：金属Ｃ＝１：０～２：０～５
　である。 Metal A: Metal B: Metal C = 1: 0 to 2: 0 to 5
It is.
　また、比較的低温での半導体変換処理では、金属Ｃの比率が上式で０～２になることが、より好ましい。明確な理由は定かではないが、金属Ｃを含む前駆体材料の酸化反応温度が比較的高いためと推定している。 In the semiconductor conversion treatment at a relatively low temperature, it is more preferable that the ratio of metal C is 0 to 2 in the above formula. Although the reason is not clear, it is presumed that the oxidation reaction temperature of the precursor material containing metal C is relatively high.
　（金属塩を溶解する溶媒）
　金属塩を溶解する溶媒としては、水の他、用いる金属化合物を溶解するものであれば特に制限はなく、水や、エタノール、プロパノール、エチレングリコールなどのアルコール類、テトラヒドロフラン、ジオキサン等のエーテル系、酢酸メチル、酢酸エチル等のエステル系、アセトン、メチルエチルケトン、シクロヘキサノン等のケトン系、ジエチレングリコールモノメチルエーテル等グリコールエーテル系、また、アセトニトリルなど、更に、キシレン、トルエン等の芳香族系溶媒、ヘキサン、シクロヘキサン、トリデカンなど、α－テルピネオール、また、クロロホルムや１，２－ジクロロエタン等のハロゲン化アルキル系溶媒、Ｎ－メチルピロリドン、２硫化炭素等を用いることができる。 (Solvent that dissolves metal salt)
The solvent for dissolving the metal salt is not particularly limited as long as it dissolves the metal compound to be used in addition to water. Water, alcohols such as ethanol, propanol and ethylene glycol, ethers such as tetrahydrofuran and dioxane, Esters such as methyl acetate and ethyl acetate, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, glycol ethers such as diethylene glycol monomethyl ether, acetonitrile, and aromatic solvents such as xylene and toluene, hexane, cyclohexane, and tridecane Α-terpineol, alkyl halide solvents such as chloroform and 1,2-dichloroethane, N-methylpyrrolidone, carbon disulfide and the like can be used.
　中でも、本発明では、水を溶媒として用い水溶液として調製することが好ましい。 Among these, in the present invention, it is preferable to prepare an aqueous solution using water as a solvent.
　尚、本発明に係る溶媒としては、単一溶媒でもよく、混合溶媒でもよい。 The solvent according to the present invention may be a single solvent or a mixed solvent.
　また、上記の硝酸塩等の金属塩は、水に対して分解性がなく、水を溶媒として用いることができるので、製造工程上、また環境上も好ましく用いることができる。 Further, the above metal salts such as nitrates are not decomposable with respect to water, and water can be used as a solvent, so that they can be preferably used in the production process and the environment.
　例えば、金属塩化物等の金属塩は大気中での劣化、分解と（特にガリウム等の場合）、強い潮解性とが激しいが、本発明に係る硝酸塩等の無機塩については潮解、また劣化等がなく使い易いことも製造環境上好ましい。 For example, metal salts such as metal chlorides are severely deteriorated and decomposed in the atmosphere (particularly in the case of gallium, etc.) and strong deliquescence. However, inorganic salts such as nitrates according to the present invention are deliquescent and deteriorated. It is also preferable in terms of manufacturing environment that it is easy to use.
　本発明に係る金属塩中でも、水に対する劣化、分解、また容易に溶けること、更に、潮解性等の性能においても優れた性質を示す硝酸塩が最も好ましい。 Among the metal salts according to the present invention, nitrates that exhibit excellent properties in terms of performance such as degradation, decomposition, and easy dissolution in water and deliquescence are most preferable.
　本発明においては、金属塩を含有する水溶液を基材上に塗布・成膜することにより、金属酸化物前駆体を含有する薄膜を形成する。 In the present invention, a thin film containing a metal oxide precursor is formed by applying and forming an aqueous solution containing a metal salt on a substrate.
　金属塩を含有する水溶液を基材上に塗布・成膜して、金属酸化物前駆体薄膜を形成する方法としては、スプレーコート法、スピンコート法、ブレードコート法、ディップコート法、キャスト法、ロールコート法、バーコート法、ダイコート法、ミスト法、など、凸版、凹版、平版、スクリーン印刷、インクジェットなどの印刷法等、広い意味での塗布による方法が挙げられ、また、これによりパターン化する方法などが挙げられる。塗布膜からフォトリソグラフ法、レーザーアブレーションなどによりパターン化してもよい。 As a method of forming a metal oxide precursor thin film by coating and forming an aqueous solution containing a metal salt on a substrate, a spray coating method, a spin coating method, a blade coating method, a dip coating method, a casting method, Examples include roll coating methods, bar coating methods, die coating methods, mist methods, printing methods such as relief printing, intaglio printing, lithographic printing, screen printing, and ink jet printing, and methods using coating in a broad sense. The method etc. are mentioned. The coating film may be patterned by photolithography, laser ablation, or the like.
　これらのうち、液滴噴射方式のパターニングが可能で、薄膜の塗布が可能な、インクジェット法、スプレーコート法等であり、特に好ましくは、インクジェット法である。 Among these, an ink jet method, a spray coating method, and the like that can be patterned by a droplet jetting method and can be applied with a thin film, and an ink jet method is particularly preferable.
　例えば、インクジェット法を用いて塗布・成膜する場合、金属塩水溶液を滴下して、１５０℃程度で溶媒（水）を揮発させることにより金属塩を含有する半導体前駆体層薄膜が形成される。尚、溶液を滴下する際、基材（基板ともいう）の温度（℃）を溶液の主溶媒の沸点（℃）の５０％～１５０％の温度範囲に調整して前記溶液を塗布・成膜する工程を有することにより、塗布、乾燥の２プロセスを同時に行うことができるので好ましい態様として挙げられる。 For example, when coating and film-forming using an inkjet method, a semiconductor precursor layer thin film containing a metal salt is formed by dropping a metal salt aqueous solution and volatilizing a solvent (water) at about 150 ° C. In addition, when dropping the solution, the temperature (° C.) of the base material (also referred to as a substrate) is adjusted to a temperature range of 50% to 150% of the boiling point (° C.) of the main solvent of the solution, and the solution is applied and formed into a film. By having the process to perform, two processes of coating and drying can be performed at the same time.
　（半導体前駆体層（金属酸化物前駆体薄膜）の膜厚）
　本発明に係る半導体前駆体層の膜厚は１ｎｍ～２００ｎｍ、好ましくは５ｎｍ～１００ｎｍの範囲に調整されることが好ましい。 (Film thickness of semiconductor precursor layer (metal oxide precursor thin film))
The thickness of the semiconductor precursor layer according to the present invention is preferably adjusted in the range of 1 nm to 200 nm, preferably 5 nm to 100 nm.
　《金属酸化物半導体層（金属酸化物層、金属酸化物膜ともいう）の作製方法》
　本発明に係る金属酸化物半導体層（金属酸化物層）の作製方法について説明する。 << Method for manufacturing metal oxide semiconductor layer (also referred to as metal oxide layer or metal oxide film) >>
A method for manufacturing a metal oxide semiconductor layer (metal oxide layer) according to the present invention will be described.
　本発明に係る金属酸化物前駆体薄膜に含有される金属イオン（金属塩ともいう）を酸化処理することにより、本発明に係る金属酸化物層（金属酸化物膜ともいう）を得ることができる。 A metal oxide layer (also referred to as a metal oxide film) according to the present invention can be obtained by oxidizing a metal ion (also referred to as a metal salt) contained in the metal oxide precursor thin film according to the present invention. .
　本発明に係る金属酸化物半導体層としては、硝酸塩、硫酸塩、燐酸塩、炭酸塩、酢酸塩または蓚酸塩から選ばれる金属塩の少なくとも１つを酸化処理して得られる金属酸化物半導体を含有する層が好ましい。 The metal oxide semiconductor layer according to the present invention includes a metal oxide semiconductor obtained by oxidizing at least one of metal salts selected from nitrates, sulfates, phosphates, carbonates, acetates or oxalates. A layer is preferred.
　（金属酸化物半導体）
　本発明に係る金属酸化物半導体としては、単結晶、多結晶、非晶質のいずれの状態も使用可能であるが、好ましくは非晶質の酸化物が用いられる。 (Metal oxide semiconductor)
As the metal oxide semiconductor according to the present invention, any state of single crystal, polycrystal, and amorphous can be used, but an amorphous oxide is preferably used.
　金属酸化物半導体の前駆体となる金属化合物材料から形成された、本発明に係る金属酸化物である非晶質酸化物の電子キャリア濃度は１０１８／ｃｍ３未満が実現されていればよい。 The electron carrier concentration of an amorphous oxide, which is a metal oxide according to the present invention, formed from a metal compound material that is a precursor of a metal oxide semiconductor only needs to be less than 10 18 / cm 3 .
　電子キャリア濃度は室温で測定する場合の値である。室温とは、例えば２５℃であり、具体的には０℃～４０℃程度の範囲から適宜選択されるある温度である。 The electron carrier concentration is a value measured at room temperature. The room temperature is, for example, 25 ° C., specifically, a certain temperature appropriately selected from the range of about 0 ° C. to 40 ° C.
　尚、本発明に係るアモルファス酸化物の電子キャリア濃度は、０℃～４０℃の範囲全てにおいて、１０１８／ｃｍ３未満を充足していなくてもよい。 Note that the electron carrier concentration of the amorphous oxide according to the present invention may not satisfy less than 10 18 / cm 3 in the entire range of 0 ° C. to 40 ° C.
　例えば、２５℃において、キャリア電子密度１０１８／ｃｍ３未満が実現されていればよい。また、電子キャリア濃度を更に下げ、１０１７／ｃｍ３以下、より好ましくは１０１６／ｃｍ３以下にするとノーマリーオフのＴＦＴが歩留まり良く得られる。 For example, a carrier electron density of less than 10 18 / cm 3 may be realized at 25 ° C. Further, when the electron carrier concentration is further reduced to 10 17 / cm 3 or less, more preferably 10 16 / cm 3 or less, a normally-off TFT can be obtained with a high yield.
　電子キャリア濃度の測定は、ホール効果測定により求めることができる。 The measurement of electron carrier concentration can be obtained by Hall effect measurement.
　金属酸化物半導体を含有する半導体活性層の膜厚としては、得られたトランジスタの特性は、金属酸化物半導体層の膜厚に大きく左右される場合が多く、その膜厚は、半導体により異なるが、一般に１μｍ以下、特に１０ｎｍ～３００ｎｍが好ましい。 As the film thickness of the semiconductor active layer containing a metal oxide semiconductor, the characteristics of the obtained transistor are often greatly influenced by the film thickness of the metal oxide semiconductor layer, and the film thickness varies depending on the semiconductor. Generally, it is preferably 1 μm or less, particularly preferably 10 nm to 300 nm.
　また、本発明においては、前駆体材料（金属塩）、組成比、製造条件などを制御して、例えば、電子キャリア濃度を、１０１２／ｃｍ３以上１０１８／ｃｍ３未満であることが好ましく、更に好ましくは１０１３／ｃｍ３以上１０１７／ｃｍ３以下であり、１０１５／ｃｍ３以上１０１６／ｃｍ３以下の範囲にすることが特に好ましい。 In the present invention, the precursor material (metal salt), composition ratio, production conditions, and the like are controlled, and for example, the electron carrier concentration is preferably 10 12 / cm 3 or more and less than 10 18 / cm 3. More preferably, it is 10 13 / cm 3 or more and 10 17 / cm 3 or less, and particularly preferably in the range of 10 15 / cm 3 or more and 10 16 / cm 3 or less.
　（半導体前駆体層中の金属イオンの酸化処理による金属酸化物半導体層の形成）
　本発明に係る金属酸化物半導体層の形成方法について説明する。 (Formation of metal oxide semiconductor layer by oxidation treatment of metal ions in semiconductor precursor layer)
A method for forming a metal oxide semiconductor layer according to the present invention will be described.
　前記金属無機塩から形成された半導体前駆体層を熱処理することにより、金属酸化物半導体層に変換する方法としては、酸素プラズマ法、熱酸化法、ＵＶオゾン法等の酸化処理を挙げることができる、また、好ましい態様として、後述するマイクロ波照射を挙げることができる。 Examples of a method for converting the semiconductor precursor layer formed from the metal inorganic salt into a metal oxide semiconductor layer by heat treatment include an oxidation treatment such as an oxygen plasma method, a thermal oxidation method, and a UV ozone method. Moreover, as a preferred embodiment, microwave irradiation described later can be exemplified.
　熱酸化としては、１００℃～４００℃の範囲の温度域で加熱処理することが好ましい。反応を促進する観点で酸素の存在下で行うことがより好ましい。 As thermal oxidation, heat treatment is preferably performed in a temperature range of 100 ° C. to 400 ° C. It is more preferable to carry out in the presence of oxygen from the viewpoint of promoting the reaction.
　本発明に係る硝酸塩、硫酸塩、燐酸塩、炭酸塩、酢酸塩または蓚酸塩から選ばれる金属塩を用いることで比較的低い温度において酸化処理することができる。 The oxidation treatment can be performed at a relatively low temperature by using a metal salt selected from nitrate, sulfate, phosphate, carbonate, acetate or oxalate according to the present invention.
　また、金属酸化物の形成はＸＰＳ（Ｘ線光電子スペクトロスコピー：ＥＳＣＡともいう）等により検知でき、金属酸化物半導体や導電性材料への変換が充分行われる条件を予め選択することができる。 Further, the formation of the metal oxide can be detected by XPS (X-ray photoelectron spectroscopy: also referred to as ESCA) and the conditions under which the conversion to the metal oxide semiconductor or the conductive material is sufficiently performed can be selected in advance.
　また、酸素プラズマ法としては大気圧プラズマ法を用いるのが好ましい。また酸素プラズマ法、ＵＶオゾン法においては、基板を５０℃～３００℃の範囲で加熱させることが好ましい。 Moreover, it is preferable to use an atmospheric pressure plasma method as the oxygen plasma method. In the oxygen plasma method and the UV ozone method, the substrate is preferably heated in the range of 50 ° C. to 300 ° C.
　大気圧プラズマ法では、大気圧下で、アルゴンガス等の不活性ガスを放電ガスとして、これと共に反応ガス（酸素を含むガス）を放電空間に導入して、高周波電界を印加して、放電ガスを励起させ、プラズマ発生させ、反応ガスと接触させて酸素を含むプラズマを発生させ、基体表面をこれに晒すことで酸素プラズマ処理を行う。大気圧下とは、２０ｋＰａ～１１０ｋＰａの圧力を表すが、好ましくは９３ｋＰａ～１０４ｋＰａである。 In the atmospheric pressure plasma method, an inert gas such as argon gas is used as a discharge gas under atmospheric pressure, and a reaction gas (a gas containing oxygen) is introduced into the discharge space, and a high frequency electric field is applied to the discharge gas. Is excited to generate plasma, and contact with a reactive gas to generate plasma containing oxygen, and the substrate surface is exposed to this to perform oxygen plasma treatment. “At atmospheric pressure” represents a pressure of 20 kPa to 110 kPa, preferably 93 kPa to 104 kPa.
　大気圧プラズマ法を用いて、酸素含むガスを反応性ガスとして、酸素プラズマを発生させ、金属塩を含有する前駆体薄膜を、プラズマ空間に晒すことでプラズマ酸化により前駆体薄膜は酸化分解して、金属酸化物からなる層が形成する。 Using an atmospheric pressure plasma method, oxygen plasma is generated as a reactive gas, oxygen plasma is generated, and the precursor thin film containing a metal salt is exposed to the plasma space, so that the precursor thin film is oxidized and decomposed by plasma oxidation. A layer made of a metal oxide is formed.
　高周波電源として０．５ｋＨｚ以上、２．４５ＧＨｚ以下、また、対向電極間に供給する電力は、好ましくは０．１Ｗ／ｃｍ２以上、５０Ｗ／ｃｍ２以下の範囲に調整することである。 The high frequency power supply is 0.5 kHz or more and 2.45 GHz or less, and the power supplied between the counter electrodes is preferably adjusted to a range of 0.1 W / cm 2 or more and 50 W / cm 2 or less.
　使用するガスは、基本的に、放電ガス（不活性ガス）と、反応ガス（酸化性ガス）の混合ガスである。反応ガスは好ましくは酸素ガスであり混合ガスに対し、０．０１体積％～１０体積％含有させることが好ましい。０．１体積％～１０体積％であることがより好ましいが、更に好ましくは、０．１体積％～５体積％である。 The gas used is basically a mixed gas of a discharge gas (inert gas) and a reaction gas (oxidizing gas). The reaction gas is preferably oxygen gas, and is preferably contained in an amount of 0.01 to 10% by volume with respect to the mixed gas. It is more preferably 0.1% by volume to 10% by volume, and still more preferably 0.1% by volume to 5% by volume.
　上記不活性ガスとしては、周期表の第１８族元素、具体的には、ヘリウム、ネオン、アルゴン、クリプトン、キセノン、ラドンや、窒素ガス等が挙げられるが、本発明に記載の効果を得るためには、ヘリウム、アルゴン、窒素ガスが好ましい。 Examples of the inert gas include Group 18 elements of the periodic table, specifically helium, neon, argon, krypton, xenon, radon, nitrogen gas, etc., in order to obtain the effects described in the present invention. Helium, argon, and nitrogen gas are preferable.
　また、反応ガスを放電空間である電極間に導入するには、常温常圧で構わない。 Moreover, normal temperature and normal pressure may be used to introduce the reaction gas between the electrodes which are the discharge space.
　大気圧下でのプラズマ法については、例えば、特開平１１－６１４０６号公報、同１１－１３３２０５号公報、特開２０００－１２１８０４号公報、同２０００－１４７２０９号公報、同２０００－１８５３６２号公報等に記載されている。 Regarding the plasma method under atmospheric pressure, for example, see JP-A-11-61406, JP-A-11-133205, JP-A-2000-121804, JP-A-2000-147209, JP-A-2000-185362. Are listed.
　また、ＵＶオゾン法は、酸素の存在下で、紫外光を照射し、酸化反応を進行させる方法である。紫外光の波長は、１００ｎｍ～４５０ｎｍ、特に好ましくは１５０ｎｍ～３００ｎｍ程度の所謂、真空紫外光を照射することが好ましい。 Further, the UV ozone method is a method in which an oxidation reaction is advanced by irradiating ultraviolet light in the presence of oxygen. It is preferable to irradiate so-called vacuum ultraviolet light having a wavelength of ultraviolet light of about 100 nm to 450 nm, particularly preferably about 150 nm to 300 nm.
　光源は、低圧水銀灯、重水素ランプ、キセノンエキシマーランプ、メタルハライドランプ、エキシマーレーザーなどを用いることができる。 The light source may be a low-pressure mercury lamp, deuterium lamp, xenon excimer lamp, metal halide lamp, excimer laser, or the like.
　ランプの出力としては４００Ｗ～３０ｋＷ、照度としては１００ｍＷ／ｃｍ２～１００ｋＷ／ｃｍ２、照射エネルギーとしては１０ｍＪ／ｃｍ２～５０００ｍＪ／ｃｍ２が好ましく、１００ｍＪ／ｃｍ２～２０００ｍＪ／ｃｍ２がより好ましい。 Lamp 400W ~ 30 kW as an output, and more preferably preferably 10mJ / cm 2 ~ 5000mJ / cm 2, 100mJ / cm 2 ~ 2000mJ / cm 2 as 100mW / cm 2 ~ 100kW / cm 2, irradiation energy as illuminance .
　紫外線照射の際の照度は１ｍＷ～１０Ｗ／ｃｍ２が好ましい。 The illuminance upon UV irradiation is preferably 1 mW to 10 W / cm 2 .
　また、本発明では、酸化処理に加えて前記酸化処理の後、または、前記酸化処理と同時に加熱処理を施すことが好ましい。これにより酸化処理を促進することができる。 In the present invention, it is preferable to perform heat treatment after the oxidation treatment or simultaneously with the oxidation treatment in addition to the oxidation treatment. Thereby, oxidation treatment can be promoted.
　具体的には、本発明に係る半導体前駆体層（金属酸化物前駆体薄膜）を酸化処理したのち、基板（基材ともいう）を５０℃～２００℃、好ましくは８０℃～１５０℃の範囲で、加熱時間としては１分～１０時間の範囲で加熱することが好ましい。 Specifically, after oxidizing the semiconductor precursor layer (metal oxide precursor thin film) according to the present invention, the substrate (also referred to as a base material) is in the range of 50 ° C. to 200 ° C., preferably 80 ° C. to 150 ° C. The heating time is preferably 1 minute to 10 hours.
　加熱処理は、酸化処理と同時に行ってもよく、酸化による金属酸化物半導体への変換を迅速に行うことができる。 The heat treatment may be performed simultaneously with the oxidation treatment, and can be rapidly converted into a metal oxide semiconductor by oxidation.
　金属イオンの酸化処理により形成される、金属酸化物半導体層の膜厚は１ｎｍ～２００ｎｍ、より好ましくは５ｎｍ～１００ｎｍが好ましい。 The film thickness of the metal oxide semiconductor layer formed by oxidation treatment of metal ions is preferably 1 nm to 200 nm, more preferably 5 nm to 100 nm.
　（マイクロ波の照射による酸化処理）
　本発明においては、半導体前駆体（金属酸化物前駆体）となる前記金属無機塩材料から形成された薄膜を金属酸化物半導体に変換（酸化変換）する方法として、マイクロ波照射マイクロ波（０．３ＧＨｚ～５０ＧＨｚ）を用いることが好ましい。尚、酸素の存在下で照射することにより、酸化変換を促進することが可能であり、より好ましい。 (Oxidation treatment by microwave irradiation)
In the present invention, as a method for converting (oxidizing) a thin film formed from the metal inorganic salt material to be a semiconductor precursor (metal oxide precursor) into a metal oxide semiconductor, microwave irradiation microwave (0. 3 GHz to 50 GHz) is preferably used. In addition, it is possible to accelerate | stimulate oxidation conversion by irradiating in presence of oxygen, and it is more preferable.
　即ち、これらの金属酸化物前駆体となる前記金属塩材料を含む薄膜を形成した後、該薄膜に対し、酸素の存在下で電磁波、特にマイクロ波（周波数０．５ＧＨｚ～５０ＧＨｚ）を照射することが好ましい。 That is, after forming a thin film containing the metal salt material to be a precursor of these metal oxides, the thin film is irradiated with electromagnetic waves, particularly microwaves (frequency 0.5 GHz to 50 GHz) in the presence of oxygen. Is preferred.
　金属酸化物半導体の前駆体となる前記金属塩材料を含む薄膜にマイクロ波を照射することで、金属酸化物前駆体中の電子が振動し、ジュール熱が発生して薄膜が内部から、均一に加熱される。ガラスや樹脂等の基板には、マイクロ波領域に吸収が殆ど無いため、基板自体は殆ど発熱せずに薄膜部のみを選択的に加熱し熱酸化、金属酸化物半導体または導電性材料に変換することが可能となる。 By irradiating the thin film containing the metal salt material, which is a precursor of the metal oxide semiconductor, with microwaves, electrons in the metal oxide precursor vibrate, Joule heat is generated, and the thin film is uniformly distributed from the inside. Heated. Since substrates such as glass and resin have almost no absorption in the microwave region, the substrate itself hardly generates heat, and only the thin film portion is selectively heated to be thermally oxidized, converted into a metal oxide semiconductor or a conductive material. It becomes possible.
　マイクロ波加熱においては一般的な様に、マイクロ波吸収は吸収が強い物質に集中し、尚且つ非常に短時間で５００℃～６００℃まで昇温することが可能なため、本発明にこの方法を用いた場合に、基材自身には殆ど電磁波による加熱の影響を与えず、短時間で前駆体薄膜のみを酸化反応が起きる温度まで昇温でき、金属酸化物前駆体を金属酸化物に変換することが可能となる。 As is generally the case with microwave heating, microwave absorption concentrates on strongly absorbing substances and can be heated to 500 ° C. to 600 ° C. in a very short time. When used, the base material itself is hardly affected by heating by electromagnetic waves, and only the precursor thin film can be heated to the temperature at which the oxidation reaction takes place in a short time, and the metal oxide precursor is converted to metal oxide. It becomes possible to do.
　また、加熱温度、加熱時間は照射するマイクロ波の出力、照射時間で制御することが可能であり、前駆体材料、基板材料に合わせて調整することが可能である。 Also, the heating temperature and the heating time can be controlled by the output of the microwave to be irradiated and the irradiation time, and can be adjusted according to the precursor material and the substrate material.
　一般的に、マイクロ波とは０．５ＧＨｚ～５０ＧＨｚの周波数を持つ電磁波のことを指し、携帯通信で用いられる０．８ＭＨｚ及び１．５ＧＨｚ帯、２ＧＨｚ帯、アマチュア無線、航空機レーダー等で用いられる１．２ＧＨｚ帯、電子レンジ、構内無線、ＶＩＣＳ等で用いられる２．４ＧＨｚ帯、船舶レーダー等に用いられる３ＧＨｚ帯、その他ＥＴＣの通信に用いられる５．６ＧＨｚなどは全てマイクロ波の範疇に入る電磁波である。 In general, a microwave refers to an electromagnetic wave having a frequency of 0.5 GHz to 50 GHz, and is used in 0.8 MHz and 1.5 GHz band, 2 GHz band, amateur radio, aircraft radar, etc. used in mobile communication. .2 GHz band, microwave oven, local radio, 2.4 GHz band used for VICS, 3 GHz band used for ship radar, etc., and 5.6 GHz used for other ETC communications are all electromagnetic waves in the microwave category. is there.
　セラミクスの分野では、この様な電磁波を焼結に利用することが既に公知であり、磁性を含む材料に電磁波を照射すると、その物質の複素透磁率の損失部の大きさに応じて発熱することを利用し、短時間で均一に、かつ高温にすることができる。 In the field of ceramics, it is already known to use such electromagnetic waves for sintering, and when a material containing magnetism is irradiated with electromagnetic waves, it generates heat according to the size of the loss portion of the complex permeability of the substance. Can be used to achieve a uniform and high temperature in a short time.
　一方で、金属にマイクロ波を照射すると自由電子が高い周波数で運動を始めるためアーク放電が発生し、加熱できないことも良く知られている。 On the other hand, it is also well known that when a metal is irradiated with microwaves, free electrons begin to move at a high frequency and arc discharge is generated and heating is not possible.
　この様に、本発明の金属酸化物半導体の前駆体は、セラミクスと同様に選択的に短時間で均一に、且つ、高温まで加熱できる。 Thus, the precursor of the metal oxide semiconductor of the present invention can be selectively heated uniformly to a high temperature in a short time, similarly to ceramics.
　前記金属塩を含有する半導体前駆体層にマイクロ波照射を行って、半導体変換処理を行う方法は、短時間で選択的に酸化反応を進行させる方法である。 The method of performing semiconductor conversion treatment by irradiating the semiconductor precursor layer containing the metal salt with microwaves is a method in which an oxidation reaction is selectively advanced in a short time.
　但し、熱伝導により少なからず基材にも熱が伝わるため、特に樹脂基板のような耐熱性の低い基材の場合は、マイクロ波の出力、照射時間、更には照射回数を制御することで基板温度が５０℃～２００℃、前駆体を含有する薄膜の表面温度が２００℃～６００℃になるように処理することが好ましい。 However, heat is transferred to the base material due to heat conduction, so in the case of a base material with low heat resistance such as a resin substrate, the substrate can be controlled by controlling the microwave output, irradiation time, and the number of times of irradiation. It is preferable to perform the treatment so that the temperature is 50 ° C. to 200 ° C. and the surface temperature of the precursor-containing thin film is 200 ° C. to 600 ° C.
　薄膜表面の温度、基板の温度等は熱電対を用いた表面温度計、また非接触の表面温度計により測定が可能である。 The temperature of the thin film surface, the temperature of the substrate, etc. can be measured with a surface thermometer using a thermocouple or a non-contact surface thermometer.
　本発明に係る金属塩から形成される金属酸化物半導体薄膜は、各種の素子、また電子回路等に用いることができ、基板上に前駆体材料の水溶液を塗布することによって低温プロセスでの金属酸化物半導体材料層の作製が可能であり、樹脂基板を用いる電子デバイス、中でも、特に薄膜トランジスタ（ＴＦＴ）の製造に好ましく適用することができる。 The metal oxide semiconductor thin film formed from the metal salt according to the present invention can be used in various devices, electronic circuits, etc., and is applied to a metal oxide in a low temperature process by applying an aqueous solution of a precursor material on a substrate. A physical semiconductor material layer can be produced, and can be preferably applied to the manufacture of an electronic device using a resin substrate, especially a thin film transistor (TFT).
　次いで、本発明の薄膜トランジスタを構成する各要素について説明する。 Next, each element constituting the thin film transistor of the present invention will be described.
　（電極）
　本発明において、薄膜トランジスタを構成するソース電極、ドレイン電極、ゲート電極等の電極に用いられる導電性材料としては、電極として実用可能なレベルでの導電性があればよく、特に限定されず、白金、金、銀、ニッケル、クロム、銅、鉄、錫、アンチモン鉛、タンタル、インジウム、パラジウム、テルル、レニウム、イリジウム、アルミニウム、ルテニウム、ゲルマニウム、モリブデン、タングステン、酸化スズ・アンチモン、酸化インジウム・スズ（ＩＴＯ）、フッ素ドープ酸化亜鉛、亜鉛、炭素、グラファイト、グラッシーカーボン、銀ペースト及びカーボンペースト、リチウム、ベリリウム、ナトリウム、マグネシウム、カリウム、カルシウム、スカンジウム、チタン、マンガン、ジルコニウム、ガリウム、ニオブ、ナトリウム、ナトリウム－カリウム合金、マグネシウム、リチウム、アルミニウム、マグネシウム／銅混合物、マグネシウム／銀混合物、マグネシウム／アルミニウム混合物、マグネシウム／インジウム混合物、アルミニウム／酸化アルミニウム混合物、リチウム／アルミニウム混合物等が用いられる。 (electrode)
In the present invention, the conductive material used for the electrodes such as the source electrode, the drain electrode, and the gate electrode constituting the thin film transistor is not particularly limited as long as it has conductivity at a practical level as an electrode. Gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, tin oxide / antimony, indium tin oxide (ITO ), Fluorine-doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste and carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium, manganese, zirconium, gallium, niobium, sodium Beam, sodium - potassium alloy, magnesium, lithium, aluminum, magnesium / copper mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide mixture, a lithium / aluminum mixture, or the like is used.
　特に本発明のゲート電極を構成する金属材料としては、タンタル、アルミニウム、チタン、ニオブ、ネオジウム、ジルコニウム、ハフニウム、クロム、モリブデンからなる群から選択された金属材料及びこれらの合金を用いることが好ましい。 In particular, it is preferable to use a metal material selected from the group consisting of tantalum, aluminum, titanium, niobium, neodymium, zirconium, hafnium, chromium, molybdenum and alloys thereof as the metal material constituting the gate electrode of the present invention.
　本発明に係るゲート電極は、上記の金属材料のみから構成されていてもよいが、別の好ましい態様としては、基板側から金属酸化物導電層、金属材料を含有する金属層の少なくとも２層からなる構成を挙げることができる。 The gate electrode according to the present invention may be composed of only the above metal material. However, as another preferred aspect, the gate electrode is composed of at least two layers of a metal oxide conductive layer and a metal layer containing a metal material from the substrate side. The structure which becomes can be mentioned.
　更に、本発明では、上記の金属層を陽極酸化することによりゲート絶縁膜を形成することができる。 Furthermore, in the present invention, the gate insulating film can be formed by anodizing the metal layer.
　（金属酸化物導電層）
　本発明に係る金属酸化物導電層について説明する。 (Metal oxide conductive layer)
The metal oxide conductive layer according to the present invention will be described.
　本発明に係る金属酸化物導電層としては、上記のマイクロ波を吸収可能なＩＴＯ、ＺｎＯ、ＳｎＯ２の様な金属酸化物導電体により構成されていることが好ましい。 The metal oxide conductive layer according to the present invention is preferably composed of a metal oxide conductor such as ITO, ZnO, or SnO 2 capable of absorbing the above microwaves.
　本発明では、上記のマイクロ波の照射を、半導体前駆体層を有する基板の裏面側から照射することにより金属酸化物導電層が発熱し、前記半導体前駆体層を金属酸化物半導体層に効率よく変換することが可能となる。 In the present invention, the metal oxide conductive layer generates heat by irradiating the above microwave irradiation from the back side of the substrate having the semiconductor precursor layer, and the semiconductor precursor layer is efficiently applied to the metal oxide semiconductor layer. It becomes possible to convert.
　（電極等の形成方法）
　電極の形成方法としては、蒸着やスパッタリング等の方法を用いて形成した導電性薄膜を、公知のフォトリソグラフ法やリフトオフ法を用いて電極形成する方法、アルミニウムや銅などの金属箔上に熱転写、インクジェット等により、レジストを形成しエッチングする方法がある。また導電性ポリマーの溶液または分散液、金属微粒子を含有する分散液等を直接インクジェット法によりパターニングしてもよいし、塗工膜からリソグラフやレーザーアブレーションなどにより形成してもよい。 (Method for forming electrodes, etc.)
As an electrode forming method, a conductive thin film formed using a method such as vapor deposition or sputtering, a method of forming an electrode using a known photolithographic method or a lift-off method, thermal transfer onto a metal foil such as aluminum or copper, There is a method of forming and etching a resist by ink jet or the like. Alternatively, a conductive polymer solution or dispersion, a dispersion containing metal fine particles, or the like may be directly patterned by an ink jet method, or may be formed from a coating film by lithography or laser ablation.
　更に、導電性ポリマーや金属微粒子を含有する導電性インク、導電性ペーストなどを凸版、凹版、平版、スクリーン印刷などの印刷法でパターニングする方法も用いることができる。 Furthermore, a method of patterning a conductive ink or conductive paste containing a conductive polymer or metal fine particles by a printing method such as relief printing, intaglio printing, planographic printing or screen printing can also be used.
　ソース、ドレインまたはゲート電極等の電極、また、ゲートまたはソースバスライン等を、エッチングまたはリフトオフ等感光性樹脂等を用いた金属薄膜のパターニングなしに形成する方法として、無電解メッキ法による方法が知られている。 An electroless plating method is known as a method for forming an electrode such as a source, drain or gate electrode, or a gate or source bus line without patterning a metal thin film using a photosensitive resin such as etching or lift-off. It has been.
　無電解メッキ法による電極の形成方法に関しては、特開２００４－１５８８０５号公報にも記載されたように、電極を設ける部分に、メッキ剤と作用して無電解メッキを生じさせるメッキ触媒を含有する液体を、例えば印刷法（インクジェット印刷含む。）によって、パターニングした後に、メッキ剤を、電極を設ける部分に接触させる。そうすると、前記触媒とメッキ剤との接触により前記部分に無電解メッキが施されて、電極パターンが形成されるというものである。 Regarding the method of forming an electrode by an electroless plating method, as described in Japanese Patent Application Laid-Open No. 2004-158805, the portion where the electrode is provided contains a plating catalyst that causes electroless plating by acting with a plating agent. After the liquid is patterned by, for example, a printing method (including ink jet printing), a plating agent is brought into contact with a portion where an electrode is provided. If it does so, electroless plating will be performed to the said part by the contact of the said catalyst and a plating agent, and an electrode pattern will be formed.
　無電解メッキの触媒と、メッキ剤の適用を逆にしてもよく、またパターン形成をどちらで行ってもよいが、メッキ触媒パターンを形成し、これにメッキ剤を適用する方法が好ましい。 The application of the electroless plating catalyst and the plating agent may be reversed, and the pattern formation may be performed either. However, a method of forming a plating catalyst pattern and applying the plating agent to this is preferable.
　印刷法としては、例えば、スクリーン印刷、平版、凸版、凹版又インクジェット法による印刷などが用いられる。 As the printing method, for example, screen printing, planographic printing, letterpress printing, intaglio printing, printing by ink jet printing, or the like is used.
　（ゲート絶縁膜）
　本発明の薄膜トランジスタのゲート絶縁膜としては種々の絶縁膜を用いることができるが、特に、比誘電率の高い無機酸化物皮膜が好ましい。無機酸化物としては、酸化ケイ素、酸化アルミニウム、酸化タンタル、酸化チタン、酸化スズ、酸化バナジウム、チタン酸バリウムストロンチウム、ジルコニウム酸チタン酸バリウム、ジルコニウム酸チタン酸鉛、チタン酸鉛ランタン、チタン酸ストロンチウム、チタン酸バリウム、フッ化バリウムマグネシウム、チタン酸ビスマス、チタン酸ストロンチウムビスマス、タンタル酸ストロンチウムビスマス、タンタル酸ニオブ酸ビスマス、トリオキサイドイットリウムなどが挙げられる。 (Gate insulation film)
Although various insulating films can be used as the gate insulating film of the thin film transistor of the present invention, an inorganic oxide film having a high relative dielectric constant is particularly preferable. Inorganic oxides include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Examples thereof include barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide.
　それらのうち好ましいのは、酸化ケイ素、酸化アルミニウム、酸化タンタル、酸化チタンである。 Of these, silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable.
　本発明では、ゲート絶縁膜（層）が陽極酸化膜または該陽極酸化膜と絶縁膜とで構成されることが好ましい。陽極酸化することで低温において絶縁性の良好なゲート絶縁膜が得られるばかりでなく、金属のマイグレーションによる突起を平滑化することが可能で有り、良好な半導体界面を形成することが可能になる。 In the present invention, the gate insulating film (layer) is preferably composed of an anodized film or the anodized film and an insulating film. By anodizing, not only a gate insulating film having a good insulating property at a low temperature can be obtained, but also a projection due to metal migration can be smoothed, and a good semiconductor interface can be formed.
　また、陽極酸化膜は封孔処理されることが望ましい。陽極酸化膜は、陽極酸化が可能な金属を公知の方法により陽極酸化することにより形成される。 Also, the anodized film is preferably sealed. The anodized film is formed by anodizing a metal that can be anodized by a known method.
　陽極酸化処理可能な金属としては、アルミニウムまたはタンタルを挙げることができ、陽極酸化処理の方法には特に制限はなく、公知の方法を用いることができる。 Examples of the metal that can be anodized include aluminum and tantalum, and the anodizing method is not particularly limited, and a known method can be used.
　無機酸化物皮膜と有機酸化物皮膜は積層して併用することができる。またこれら絶縁膜の膜厚としては、一般に５０ｎｍ～３μｍ、好ましくは、１００ｎｍ～１μｍである。 An inorganic oxide film and an organic oxide film can be laminated and used together. The thickness of these insulating films is generally 50 nm to 3 μm, preferably 100 nm to 1 μm.
　（基板）
　基板を構成する支持体材料としては、種々の材料が利用可能であり、例えば、ガラス、石英、酸化アルミニウム、サファイア、チッ化珪素、炭化珪素などのセラミック基板、シリコン、ゲルマニウム、ガリウム砒素、ガリウム燐、ガリウム窒素など半導体基板、紙、不織布などを用いることができるが、本発明において支持体は樹脂からなることが好ましく、例えばプラスチックフィルムシートを用いることができる。プラスチックフィルムとしては、例えばポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）、ポリエーテルスルホン（ＰＥＳ）、ポリエーテルイミド、ポリエーテルエーテルケトン、ポリフェニレンスルフィド、ポリアリレート、ポリイミド、ボリカーボネート（ＰＣ）、セルローストリアセテート（ＴＡＣ）、セルロースアセテートプロピオネート（ＣＡＰ）等からなるフィルム等が挙げられる。プラスチックフィルムを用いることで、ガラス基板を用いる場合に比べて軽量化を図ることができ、可搬性を高めることができるとともに、衝撃に対する耐性を向上できる。 (substrate)
Various materials can be used as the support material constituting the substrate. For example, ceramic substrates such as glass, quartz, aluminum oxide, sapphire, silicon nitride, silicon carbide, silicon, germanium, gallium arsenide, gallium phosphide. In addition, a semiconductor substrate such as gallium nitrogen, paper, and non-woven fabric can be used. In the present invention, the support is preferably made of a resin, for example, a plastic film sheet can be used. Examples of plastic films include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose. Examples include films made of triacetate (TAC), cellulose acetate propionate (CAP), and the like. By using a plastic film, the weight can be reduced as compared with the case of using a glass substrate, the portability can be improved, and the resistance to impact can be improved.
　また本発明の薄膜トランジスタ素子上には素子保護層を設けることも可能である。保護層としては前述した無機酸化物または無機窒化物等が挙げられ、上述した大気圧プラズマ法で形成するのが好ましい。 It is also possible to provide an element protective layer on the thin film transistor element of the present invention. Examples of the protective layer include the inorganic oxides and inorganic nitrides described above, and it is preferable to form the protective layer by the atmospheric pressure plasma method described above.
　以下、実施例により本発明を具体的に説明するが本発明はこれらに限定されない。 Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
　実施例１
　図１に、本発明の薄膜トランジスタ素子１の製造プロセスを概略の断面図で示した。 Example 1
FIG. 1 is a schematic sectional view showing a manufacturing process of the thin film transistor element 1 of the present invention.
　《薄膜トランジスタ素子１の製造》
　ガラス基板１（厚み０．５ｍｍ）上にＴａ薄膜（２５０ｎｍ）をスパッタにより成膜し、金属ゲート電極２（Ｔａゲート電極ともいう）を有する基板を作製した（図１（ａ）、（ｂ））。 << Manufacture of Thin Film Transistor Element 1 >>
A Ta thin film (250 nm) was formed by sputtering on a glass substrate 1 (thickness 0.5 mm) to produce a substrate having a metal gate electrode 2 (also referred to as Ta gate electrode) (FIGS. 1A and 1B). ).
　次いで、下記のようにして電解液による陽極酸化処理を行った。 Next, an anodizing treatment with an electrolytic solution was performed as follows.
　（陽極酸化によるゲート絶縁膜の形成）
　上記の金属ゲート電極２を陽極として用い、白金を陰極にして定電流電圧電源に接続した後、１％リン酸水溶液に浸し、０．２ｍＡ／ｃｍ２の一定電流になるように電圧を印加した。 (Formation of gate insulating film by anodic oxidation)
The metal gate electrode 2 was used as an anode, platinum was used as a cathode, connected to a constant current voltage power source, then immersed in a 1% phosphoric acid aqueous solution, and a voltage was applied so that a constant current of 0.2 mA / cm 2 was obtained. .
　その後、電圧が１００Ｖまで上昇したのを確認した後、１００Ｖ一定で電圧を印加し、１時間保持した。次いで、純水で洗浄し、７０℃、１時間、乾燥及びベークを行い、ゲート絶縁膜３（Ｔａ２Ｏ３ゲート絶縁膜ともいう）を形成した（図１（ｃ））。 Then, after confirming that the voltage rose to 100 V, the voltage was applied at a constant 100 V and held for 1 hour. Next, it was washed with pure water, dried at 70 ° C. for 1 hour, and baked to form a gate insulating film 3 (also referred to as a Ta 2 O 3 gate insulating film) (FIG. 1C).
　（金属酸化物半導体層の形成）
　上記で形成したゲート絶縁膜３上に、ＵＶ光下でオゾン洗浄処理を行った後、基板全体の温度を１００℃に保ち、Ｉｎ、Ｇａ（金属比率Ｉｎ：Ｇａ＝２：１）の硝酸塩を溶解した水溶液（水／ＥｔＯＨ＝９／１）をインクジェット法により塗布して、金属酸化物半導体前駆体層４を成膜し、次いで、電気炉で１５０℃、１０分乾燥後、２００℃で１時間焼成し、金属酸化物半導体層５（ＩＧＯ半導体層ともいう）を形成した（図１（ｄ）、（ｅ））。 (Formation of metal oxide semiconductor layer)
After performing ozone cleaning treatment under UV light on the gate insulating film 3 formed as described above, the temperature of the entire substrate is kept at 100 ° C., and nitrates of In and Ga (metal ratio In: Ga = 2: 1) are added. A dissolved aqueous solution (water / EtOH = 9/1) was applied by an ink jet method to form a metal oxide semiconductor precursor layer 4, then dried in an electric furnace at 150 ° C. for 10 minutes, and then at 200 ° C. for 1 By firing for a time, a metal oxide semiconductor layer 5 (also referred to as an IGO semiconductor layer) was formed (FIGS. 1D and 1E).
　金属酸化物半導体層５の形成後、金を用いてソース電極６、ドレイン電極７を蒸着により形成し、薄膜トランジスタ素子１を製造した。 After the formation of the metal oxide semiconductor layer 5, the source electrode 6 and the drain electrode 7 were formed by vapor deposition using gold, and the thin film transistor element 1 was manufactured.
　（薄膜トランジスタ素子１の評価）
　薄膜トランジスタ素子１のＩｄ－Ｖｇ（±４０Ｖ）測定を行ったところ、飽和領域での電界効果移動度５ｃｍ２／Ｖｓ、ＯｎＯｆｆ比８桁の良好な結果が得られた。 (Evaluation of Thin Film Transistor Element 1)
When the Id-Vg (± 40 V) measurement of the thin film transistor element 1 was performed, good results were obtained with a field effect mobility of 5 cm 2 / Vs in the saturation region and an OnOff ratio of 8 digits.
　また、Ｏｆｆ時の電流は１０－１２以下であり、良好な絶縁性を示した。 Further, the current at the time of Off was 10 −12 or less, and good insulation was shown.
　実施例２
　図２に、本発明の薄膜トランジスタ素子２の製造プロセスを概略の断面図で示した。 Example 2
FIG. 2 is a schematic sectional view showing a manufacturing process of the thin film transistor element 2 of the present invention.
　《薄膜トランジスタ素子２の製造》
　ガラス基板１１（厚み０．５ｍｍ）上に、Ａｌ中にＮｄを１．０ａｔ％混合したＡｌ－Ｎｄ薄膜（２５０ｎｍ）をスパッタにより成膜し、金属ゲート電極１２（Ａｌ－Ｎｄゲート電極ともいう）を有する基板を作製した（図２（ａ）、（ｂ））。 << Manufacture of Thin Film Transistor Element 2 >>
On a glass substrate 11 (thickness 0.5 mm), an Al—Nd thin film (250 nm) in which Nd is mixed at 1.0 at% in Al is formed by sputtering, and a metal gate electrode 12 (also referred to as an Al—Nd gate electrode). The board | substrate which has was produced (FIG. 2 (a), (b)).
　次いで、下記のようにして電解液による陽極酸化処理を行った。 Next, an anodizing treatment with an electrolytic solution was performed as follows.
　（陽極酸化によるゲート絶縁膜の形成）
　上記の金属ゲート電極１２を陽極として用い、白金を陰極にして定電流電圧電源に接続した後、電解液として３％酒石酸：エチレングリコール＝１：９の溶液を用い、０．２ｍＡ／ｃｍ２の一定電流になるように電圧を印加した。 (Formation of gate insulating film by anodic oxidation)
After using the metal gate electrode 12 as an anode and platinum as a cathode and connecting to a constant current voltage power source, a 3% tartaric acid: ethylene glycol = 1: 9 solution was used as an electrolyte, and 0.2 mA / cm 2 was used. A voltage was applied so as to obtain a constant current.
　その後、電圧が１００Ｖまで上昇したのを確認した後、１００Ｖ一定で電圧を印加し、１０分時間保持した。 Then, after confirming that the voltage rose to 100 V, the voltage was applied at a constant 100 V and held for 10 minutes.
　次いで、純水で洗浄し、１８０℃、１時間、乾燥及びベークを行い、ゲート絶縁膜１３（Ａｌ２Ｏ３ゲート絶縁膜ともいう）を形成した（図２（ｃ））。 Next, the substrate was washed with pure water, dried and baked at 180 ° C. for 1 hour to form a gate insulating film 13 (also referred to as an Al 2 O 3 gate insulating film) (FIG. 2C).
　その後、ゲート絶縁膜１３の上にポリシラザン溶液（ＮＮ１１０：ＡＺエレクトロニックマテリアル社製）を変換処理後の膜厚が１５ｎｍとなるように塗布し、ポリシラザン薄膜１４を形成した（図２（ｄ））。 Thereafter, a polysilazane solution (NN110: manufactured by AZ Electronic Materials) was applied on the gate insulating film 13 so that the film thickness after the conversion treatment was 15 nm, thereby forming a polysilazane thin film 14 (FIG. 2D).
　得られたポリシラザン薄膜１４を１５０℃で１０分間乾燥させた後、ＵＶオゾン照射器（ＵＶ－１：サムコ社製）を用いて、流量０．６Ｌ／ｍｉｎ、基板温度２００℃の条件化で３０分間、ＵＶオゾン照射処理１５を行い、ポリシラザン薄膜１４を酸化シリコンを含む絶縁膜１６に変換した（図２（ｅ））。 The obtained polysilazane thin film 14 was dried at 150 ° C. for 10 minutes, and then subjected to 30 conditions under the conditions of a flow rate of 0.6 L / min and a substrate temperature of 200 ° C. using a UV ozone irradiator (UV-1: manufactured by Samco). UV ozone irradiation treatment 15 was performed for a minute, and the polysilazane thin film 14 was converted into an insulating film 16 containing silicon oxide (FIG. 2E).
　次いで、実施例１と同様に、ゲート絶縁膜１３（陽極酸化膜ともいう）上に、インクジェット法により半導体前駆体層１７を形成した（図２（ｆ））。 Next, as in Example 1, a semiconductor precursor layer 17 was formed on the gate insulating film 13 (also referred to as an anodic oxide film) by an inkjet method (FIG. 2F).
　次いで、ガラス基板１１の裏側に、基板ガラスとＩＴＯが接するようにＩＴＯ層１９付きガラス基板２０を配置し、裏側から２．４５ＧＨｚのマイクロ波２１をガラス基板１１の温度が２００℃を保持しながら、１５分間照射し、金属酸化物半導体層１８を形成した（図２（ｇ））。 Next, the glass substrate 20 with the ITO layer 19 is disposed on the back side of the glass substrate 11 so that the substrate glass and ITO are in contact with each other, and 2.45 GHz microwaves 21 are maintained from the back side while maintaining the temperature of the glass substrate 11 at 200 ° C. For 15 minutes to form a metal oxide semiconductor layer 18 (FIG. 2G).
　金属酸化物半導体層１８の形成後、金を用いてソース電極２２、ドレイン電極２３を蒸着により形成し、薄膜トランジスタ素子２を製造した。 After forming the metal oxide semiconductor layer 18, the source electrode 22 and the drain electrode 23 were formed by vapor deposition using gold to manufacture the thin film transistor element 2.
　（薄膜トランジスタ素子２の評価）
　薄膜トランジスタ素子１－２のＩｄ－Ｖｇ（±４０Ｖ）測定を行ったところ、飽和領域での電界効果移動度９ｃｍ２／Ｖｓ、ＯｎＯｆｆ比８桁の良好な結果が得られた。 (Evaluation of thin film transistor element 2)
When the Id-Vg (± 40 V) measurement of the thin film transistor element 1-2 was performed, a good result with a field effect mobility of 9 cm 2 / Vs in the saturation region and an OnOff ratio of 8 digits was obtained.
　また、Ｏｆｆ時の電流は１０－１２以下であり、良好な絶縁性を示した。 Further, the current at the time of Off was 10 −12 or less, and good insulation was shown.
　実施例３
　図３に、本発明の薄膜トランジスタ素子３の製造プロセスを概略の断面図で示した。 Example 3
FIG. 3 is a schematic sectional view showing a manufacturing process of the thin film transistor element 3 of the present invention.
　《薄膜トランジスタ素子３の製造》
　ガラス基板３１上にＩＴＯ薄膜ラインパターン２２をスパッタにより作製し、その後、ＩＴＯ薄膜パターン３２の直上に、ＩＴＯライン幅より、広い幅でＴａの金属膜パターン３３（金属ゲート電極ともいう）を形成した（図３（ａ）、（ｂ））。 << Manufacture of Thin Film Transistor Element 3 >>
An ITO thin film line pattern 22 was formed on the glass substrate 31 by sputtering, and then a Ta metal film pattern 33 (also referred to as a metal gate electrode) having a width wider than the ITO line width was formed immediately above the ITO thin film pattern 32. (FIG. 3 (a), (b)).
　その後、実施例１と同様に陽極酸化を用いて、ゲート絶縁膜３４を形成し、次いで、塗布により金属酸化物半導体前駆体層３５を形成した（図３（ｃ）、（ｄ））。 Thereafter, the gate insulating film 34 was formed by anodic oxidation in the same manner as in Example 1, and then the metal oxide semiconductor precursor layer 35 was formed by coating (FIGS. 3C and 3D).
　次いで、ガラス基板３１の裏側から２．４５ＧＨｚのマイクロ波３６をガラス基板３１の温度が３００℃、１５分間照射し、金属酸化物半導体層３５を形成した。 Next, the microwave 36 of 2.45 GHz was irradiated from the back side of the glass substrate 31 at a temperature of the glass substrate 31 of 300 ° C. for 15 minutes to form the metal oxide semiconductor layer 35.
　金属酸化物半導体層３５を部分的に被覆するように、ソース電極３７、ドレイン電極３８を蒸着により形成し、薄膜トランジスタ素子３を作製した。 A thin film transistor element 3 was fabricated by forming a source electrode 37 and a drain electrode 38 by vapor deposition so as to partially cover the metal oxide semiconductor layer 35.
　（薄膜トランジスタ素子３の評価）
　薄膜トランジスタ素子３のＩｄ－Ｖｇ（±４０Ｖ）測定を行ったところ、飽和領域での電界効果移動度７ｃｍ２／Ｖｓ、ＯｎＯｆｆ比８桁以上の良好な結果が得られた。Ｏｆｆ時の電流は１０－１２以下であり、良好な絶縁性を示した。 (Evaluation of thin film transistor element 3)
When the Id-Vg (± 40 V) measurement of the thin film transistor element 3 was performed, a good result with a field effect mobility of 7 cm 2 / Vs in the saturation region and an OnOff ratio of 8 digits or more was obtained. The current at the time of off was 10 −12 or less, indicating good insulation.
　実施例４
　《薄膜トランジスタ素子４の製造》
　実施例３に記載の薄膜トランジスタ素子３の製造において、ガラス基板３１の代わりにポリイミド基板（膜厚２００μｍのポリイミド基板）を用いた以外は同様にして、薄膜トランジスタ素子４の製造を行った。 Example 4
<< Manufacture of Thin Film Transistor Element 4 >>
In the manufacture of the thin film transistor element 3 described in Example 3, the thin film transistor element 4 was manufactured in the same manner except that a polyimide substrate (a polyimide substrate having a film thickness of 200 μm) was used instead of the glass substrate 31.
　（薄膜トランジスタ素子４の評価）
　薄膜トランジスタ素子４のＩｄ－Ｖｇ（±４０Ｖ）測定を行ったところ、飽和領域での電界効果移動度２ｃｍ２／Ｖｓ、ＯｎＯｆｆ比７桁以上の良好な結果が得られた。 (Evaluation of Thin Film Transistor Element 4)
When the Id-Vg (± 40 V) measurement of the thin film transistor element 4 was performed, a good result with a field effect mobility of 2 cm 2 / Vs in the saturation region and an OnOff ratio of 7 digits or more was obtained.
　また、Ｏｆｆ時の電流は１０－１２以下であり、良好な絶縁性を示した。 Further, the current at the time of Off was 10 −12 or less, and good insulation was shown.
　１、２１　ガラス基板
　２　金属ゲート電極
　３、２４　ゲート絶縁膜
　４、２５　金属酸化物半導体前駆体層
　５　金属酸化物半導体層
　６、２７　ソース電極
　７、２８　ドレイン電極
　２２　ＩＴＯ薄膜ラインパターン
　２３　金属膜パターン（金属ゲート電極）
　２６　マイクロ波 DESCRIPTION OF SYMBOLS 1,21 Glass substrate 2 Metal gate electrode 3, 24 Gate insulating film 4, 25 Metal oxide semiconductor precursor layer 5 Metal oxide semiconductor layer 6, 27 Source electrode 7, 28 Drain electrode 22 ITO thin film line pattern 23 Metal film pattern (Metal gate electrode)
26 microwave

Claims (13)

  1. 　基板上に、ゲート電極、ゲート絶縁膜、金属酸化物半導体層、ソース電極及びドレイン電極を有する薄膜トランジスタの製造方法において、
    　該ゲート絶縁膜が金属酸化膜であり、該ゲート電極の表面を陽極酸化することにより、前記ゲート電極の表面上に該金属酸化膜を形成する工程を有することを特徴とする薄膜トランジスタの製造方法。     In a method for manufacturing a thin film transistor having a gate electrode, a gate insulating film, a metal oxide semiconductor layer, a source electrode, and a drain electrode on a substrate,
    A method of manufacturing a thin film transistor, comprising: forming a metal oxide film on a surface of the gate electrode by anodizing the surface of the gate electrode, wherein the gate insulating film is a metal oxide film.
  2. 　前記ゲート電極が、タンタル、アルミニウム、チタン、ニオブ、ジルコニウム、ハフニウム、ネオジウム、クロム、モリブデン及びモリブデン－タンタル合金からなる群から選択された金属材料を含有することを特徴とする請求項１に記載の薄膜トランジスタの製造方法。 The said gate electrode contains a metal material selected from the group consisting of tantalum, aluminum, titanium, niobium, zirconium, hafnium, neodymium, chromium, molybdenum and molybdenum-tantalum alloy. A method for manufacturing a thin film transistor.
  3. 　前記ゲート絶縁膜の少なくとも一部に、溶液塗布法により半導体前駆体層を形成し、該半導体前駆体層を酸化変換して金属酸化物半導体層を形成する工程を有することを特徴とする請求項１または２に記載の薄膜トランジスタの製造方法。 The method includes forming a semiconductor precursor layer on at least a part of the gate insulating film by a solution coating method, and oxidizing the semiconductor precursor layer to form a metal oxide semiconductor layer. A method for producing the thin film transistor according to 1 or 2.
  4. 　前記ゲート絶縁膜上の少なくとも一部に、溶液塗布法により酸化シリコン前駆体層を形成し、酸化変換して酸化シリコンを含む絶縁層を形成した後、酸化シリコンを含む絶縁層上に溶液塗布法により半導体前駆体層を形成し、該半導体前駆体層を酸化変換して金属酸化物半導体層を形成する工程を有することを特徴とする請求項１または２に記載の薄膜トランジスタの製造方法。 A silicon oxide precursor layer is formed on at least a part of the gate insulating film by a solution coating method, an oxidation conversion is performed to form an insulating layer containing silicon oxide, and then a solution coating method is performed on the insulating layer containing silicon oxide. The method for producing a thin film transistor according to claim 1, further comprising: forming a semiconductor precursor layer by oxidation, and oxidizing the semiconductor precursor layer to form a metal oxide semiconductor layer.
  5. 　前記金属酸化物半導体層が、少なくともＩｎ、ＺｎまたはＳｎのいずれか１つを含むことを特徴とする請求項１～４のいずれか１項に記載の薄膜トランジスタの製造方法。 The method for manufacturing a thin film transistor according to any one of claims 1 to 4, wherein the metal oxide semiconductor layer contains at least one of In, Zn, and Sn.
  6. 　前記金属酸化物半導体層が、少なくともＧａ、Ａｌのいずれか１つを含むことを特徴とする請求項１～５のいずれか１項に記載の薄膜トランジスタの製造方法。 6. The method of manufacturing a thin film transistor according to claim 1, wherein the metal oxide semiconductor layer contains at least one of Ga and Al.
  7. 　前記半導体前駆体層の酸化変換が１００℃～４００℃の温度範囲における熱処理であることを特徴とする請求項１～６のいずれか１項に記載の薄膜トランジスタの製造方法。 The method for producing a thin film transistor according to any one of claims 1 to 6, wherein the oxidation conversion of the semiconductor precursor layer is a heat treatment in a temperature range of 100 ° C to 400 ° C.
  8. 　前記半導体前駆体層が金属塩を含む水を主成分とした溶液を塗布法により、ゲート絶縁膜の表面の一部に形成される工程を有することを特徴とする請求項１～７のいずれか１項に記載の薄膜トランジスタの製造方法。 8. The method according to claim 1, wherein the semiconductor precursor layer has a step of forming a solution containing water containing a metal salt as a main component on a part of the surface of the gate insulating film by a coating method. 2. A method for producing a thin film transistor according to item 1.
  9. 　前記金属塩が金属硝酸塩を含むことを特徴とする請求項８に記載の薄膜トランジスタの製造方法。 The method of manufacturing a thin film transistor according to claim 8, wherein the metal salt includes a metal nitrate.
  10. 　前記ゲート電極が、基板側から金属酸化物導電層、金属材料を含有する金属層の少なくとも２層からなり、該金属層を陽極酸化することによりゲート絶縁膜が形成されることを特徴とする請求項１～９のいずれか１項に記載の薄膜トランジスタの製造方法。 The gate electrode includes at least two layers of a metal oxide conductive layer and a metal layer containing a metal material from the substrate side, and the gate insulating film is formed by anodizing the metal layer. Item 10. The method for producing a thin film transistor according to any one of Items 1 to 9.
  11. 　前記半導体前駆体層を酸化変換して金属酸化物半導体層に変換する工程にマイクロ波（０．３ＧＨｚ～５０ＧＨｚ）を照射することを特徴とする請求項３～１０のいずれか１項に記載の薄膜トランジスタの製造方法。 11. The microwave (0.3 GHz to 50 GHz) is irradiated in the step of converting the semiconductor precursor layer into a metal oxide semiconductor layer by oxidation conversion. A method for manufacturing a thin film transistor.
  12. 　前記マイクロ波の照射を、半導体前駆体層を有する基板の裏面側から照射し、前記金属酸化物導電層が発熱し、前記半導体前駆体層を金属酸化物半導体層に変換する工程を有することを特徴とする請求項１１に記載の薄膜トランジスタの製造方法。 The step of irradiating the microwave from the back side of the substrate having the semiconductor precursor layer, the metal oxide conductive layer generating heat, and converting the semiconductor precursor layer into a metal oxide semiconductor layer. The method of manufacturing a thin film transistor according to claim 11.
  13. 　請求項１～１２のいずれか１項に記載の薄膜トランジスタの製造方法により製造されたことを特徴とする薄膜トランジスタ。 A thin film transistor manufactured by the method for manufacturing a thin film transistor according to any one of claims 1 to 12.
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JP2012104703A (en) * 2010-11-11 2012-05-31 Hitachi Kokusai Electric Inc Method of manufacturing semiconductor device and substrate processing apparatus
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