JP5728908B2 - Gate insulating material, gate insulating film, and field effect transistor. - Google Patents

Description

  The present invention relates to a gate insulating material, a gate insulating film, and a field effect transistor.

  In recent years, field effect transistors (hereinafter referred to as FETs) using an organic semiconductor having excellent moldability as a semiconductor layer have been proposed. By using an organic semiconductor as an ink, it becomes possible to form a circuit pattern directly on a substrate by an ink jet technique or a screening technique, so that instead of a conventional FET using a semiconductor using an inorganic material, FETs using organic semiconductors are actively studied.

An important characteristic that indicates the performance of the FET is mobility. Improvement in mobility enables high-speed driving, and increases the on-current, thereby improving the switching characteristics of the FET. For example, in a liquid crystal display device, a high gradation is realized. For example, in the case of a liquid crystal display device, a mobility of 0.1 cm ² / V · sec or more is required.

  Another important characteristic is hysteresis. The hysteresis represents the fluctuation range of the current value with respect to the voltage history, and it is necessary to reduce the hysteresis value in order to stably drive the FET. By suppressing the hysteresis to a small value, the value of the current between the source electrode and the drain electrode becomes a predetermined value with respect to the gate voltage, and the driving can be stabilized.

  Yet another important characteristic is the turn-on voltage. When the current between the source electrode and the drain electrode is turned on from the off state by controlling the gate voltage, the gate voltage at which the current starts to flow is called a turn-on voltage and is also called a threshold voltage. In order to drive the FET at a low voltage, the absolute value of the turn-on voltage is preferably smaller, and ± 10 V or less is required.

  A combination of polyvinylphenol and a crosslinking agent is known as an example of a coating-type gate insulating material that is soluble in an organic solvent (see, for example, Non-Patent Document 1). However, since a large amount of polar groups such as amino groups and phenol groups remain, there is a problem that FET characteristics, particularly hysteresis, is large.

  As examples of other gate insulating materials, there are disclosed examples of FETs using polysiloxane as a gate insulating film (see, for example, Patent Documents 1 and 2), but hysteresis is not sufficiently suppressed, and turn-on is also performed. Since there is no description about voltage, it was insufficient for practical use of FET.

International Publication No. 2009/116373 Pamphlet JP 2007-154164 A

Applied PHYSICS LETTERS, 2003, vol. 82, p. 4175-4177

  An object of the present invention is to provide a gate insulating material, a gate insulating film, and a field effect transistor using the same, which have high durability, high mobility, and a high on / off ratio, and which enable low turn-on voltage and low hysteresis. That is.

The present invention relates to a gate insulating material containing a polymer and a metal compound, wherein the metal compound is a metal chelate compound or a metal alkoxide compound, and includes a magnesium compound, a zinc compound, a copper compound, an indium compound, a lanthanium compound, and a manganese compound. A gate insulating material comprising any one or more of a calcium compound, a tin compound, a titanium compound, a zirconium compound, a hafnium compound, and an aluminum compound.

Moreover, this invention is a gate insulating film obtained by heat-processing the coating film formed by apply | coating the said gate insulating material in the range of 100-300 degreeC .

  Furthermore, the present invention is a field effect transistor having a gate insulating layer containing the gate insulating film, and a gate electrode, a semiconductor layer, a source electrode, and a drain electrode.

  According to the present invention, there are provided a gate insulating material, a gate insulating film, and a field effect transistor using the same, which have high durability, high mobility, and a high on / off ratio, and which enable low turn-on voltage and low hysteresis. be able to.

Schematic sectional view showing an FET which is one embodiment of the present invention Schematic sectional view showing an FET which is another embodiment of the present invention

  The gate insulating material containing a polymer and a metal compound according to the present invention will be described. The polymer used for the gate insulating material of the present invention is preferably soluble in a solvent, and the skeleton may be linear, cyclic or branched. Moreover, it is preferable that a functional group having crosslinkability, a functional group having polarity, or a functional group for controlling various properties of the polymer is introduced into the side chain. By using a polymer in which these characteristics are controlled, in the FET element manufacturing process, for example, coating properties, surface flatness, solvent resistance, transparency, good wettability of other inks, and the like can be obtained. It is possible to obtain a good FET element that can balance all of the durability and stability after the FET element is formed.

  Further, the curing agent used in the gate insulating material of the present invention is a magnesium compound, zinc compound, copper compound, indium compound, lanthanum compound, manganese compound, calcium compound, tin compound, titanium compound, zirconium compound, hafnium compound (hereinafter referred to as aluminum). Or a metal compound other than the compound) and any one or more of the above and an aluminum compound. Thereby, it is possible to obtain an FET having high durability, high mobility, high on / off ratio, low hysteresis, and low turn-on voltage.

  A polymer gate insulating material used for forming an FET element can form an insulating film without adding a metal compound to obtain FET characteristics, but has problems such as low mobility and low on / off ratio. For this reason, the introduction of polar groups, the addition of fine particles having a high dielectric constant, the addition of metal oxides, the addition of metal compounds, etc. are usually performed.

  For example, by adding a metal compound to polysiloxane, effects such as improvement of durability by crosslinking / curing of the insulating film, improvement of mobility, and improvement of on / off ratio are obtained. However, metal compounds other than aluminum compounds still have a problem that the turn-on voltage and hysteresis are large. On the other hand, in FETs using polysiloxane added with only an aluminum compound, the turn-on voltage is reduced to around 0 V, but other than aluminum compounds. Hysteresis in the direction opposite to that when using the above metal compound occurs, and the problem remains that the hysteresis is still large.

  Therefore, in the present invention, by simultaneously using an aluminum compound and a metal compound other than the aluminum compound as a curing agent, the durability is improved, the mobility is improved, and the on / off ratio is improved. In addition, a unique phenomenon has been found in which the turn-on voltage can be adjusted to 15 V or less.

  The aluminum compound used in the present invention is preferably one that can be uniformly dissolved in a solvent, but even if it is suspended, it can be preferably used if it has a particle size of 1 μm or less by filtration or the like. Preferable examples of the aluminum compound include a metal chelate compound or a metal alkoxide compound, and specifically, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetate. Acetyl acetate bis (ethyl acetoacetate), aluminum tris (acetylacetonate), aluminum n-butoxide, aluminum t-butoxide, aluminum sec-butoxide, aluminum ethoxide, aluminum isopropoxide, aluminum hexafluoroacetylacetonate, aluminum tri Fluoroacetylacetonate, tris (2,2,6,6-tetramethyl-3,5-hept Tangionate) Aluminum compounds such as aluminum.

  A metal compound other than the aluminum compound used in the present invention is preferably one that can be uniformly dissolved in a solvent, but even if it is suspended, it can be preferably used if the particle size is 1 μm or less by filtration or the like. Preferred examples include metal chelate compounds or metal alkoxide compounds. Specific examples include ethyl acetoacetate magnesium monoisopropylate, magnesium bis (ethylacetoacetate), alkyl acetoacetate magnesium monoisopropylate, magnesium bis (acetylacetonate). ) And other magnesium compounds, zinc compounds such as zinc bis (ethyl acetoacetate) and zinc bis (acetylacetonate), copper compounds such as copper bis (ethyl acetoacetate) and copper bis (acetylacetonate), nickel bis (ethyl Acetoacetate), nickel compounds such as nickel bis (acetylacetonate), chromium tris (ethyl acetoacetate), chromium compounds such as chromium tris (acetylacetonate), co Cobalt compounds such as Lutotris (ethyl acetoacetate), cobalt tris (acetylacetonate), iron compounds such as iron tris (ethylacetoacetate) and iron tris (acetylacetonate), indium tris (ethylacetoacetate), indium tris ( Indium compounds such as acetylacetonate), lanthanum compounds such as lanthanum tris (ethyl acetoacetate), lanthanum tris (acetylacetonate), zirconia tetrakis (ethyl acetoacetate), zirconia tetrakis (acetylacetonate), zirconium n-butoxide, Zirconium t-butoxide, zirconium ethoxide, zirconium isopropoxide, zirconium n-propoxide, zirconium hexafluoroacetylacetonate Zirconium trifluoroacetylacetonate, tetrakis (diethylamino) zirconium, tetrakis (dimethylamino) zirconium, tetrakis (2,2,6,6-tetramethyl-3,5-heptanedionate) zirconium, zirconium sulfate tetrahydrate, etc. Zirconia compounds, tin tetrakis (ethyl acetoacetate), tin tetrakis (acetylacetonate), etc. tin compounds, titanium tetrakis (ethyl acetoacetate), titanium tetrakis (acetylacetonate), titanium tetraisopropoxide, titanium n- Butoxide, titanium t-butoxide, titanium ethoxide, titanium 2-ethylhexoxide, titanium isopropoxide, titanium (diisopropoxide) bis (acetyl) Ruacetonate), titanium oxide bis (acetylacetonate), trichlorotris (tetrahydrofuran) titanium, tris (2,2,6,6-tetramethyl-3,5-heptanedionate) titanium, (trimethyl) pentamethylcyclopentadi Enyl titanium, pentamethylcyclopentadienyl titanium trichloride, pentamethylcyclopentadienyl titanium trimethoxide, tetrachlorobis (cyclohexyl mercapto) titanium, tetrachlorobis (tetrahydrofuran) titanium, tetrachlorodiamine titanium, tetrakis (diethylamino) Titanium, tetrakis (dimethylamino) titanium, bis (t-butylcyclopentadienyl) titanium dichloride, bis (cyclopen Dienyl) dicarbonyltitanium, bis (cyclopentadienyl) titanium dichloride, bis (ethylcyclopentadienyl) titanium dichloride, bis (pentamethylcyclopentadienyl) titanium dichloride, bis (isopropylcyclopentadienyl) titanium dichloride, Tris (2,2,6,6-tetramethyl-3,5-heptanedionate) oxotitanium, chlorotitanium triisopropoxide, cyclopentadienyltitanium trichloride, dichlorobis (2,2,6,6-tetra Methyl-3,5-heptanedionate) titanium, dimethylbis (t-butylcyclopentadienyl) titanium, di (isopropoxide) bis (2,2,6,6-tetramethyl-3,5-heptanedio Naruto There are titanium compounds such as titanium, hafnium compounds such as hafnium n-butoxide, hafnium t-butoxide, hafnium ethoxide, hafnium isopropoxide, hafnium isopropoxide monoisopropylate, hafnium acetylacetonate, tetrakis (dimethylamino) hafnium Any of them can be used.

  As the metal compound other than the aluminum compound to be combined with the aluminum compound, a zirconia compound, a hafnium compound, or a titanium compound is preferable, and among them, a zirconia compound is more preferable.

  The mixing ratio of the aluminum compound to be contained in the polymer and the metal compound other than the aluminum compound is preferably 100/1 to 100/500, more preferably 100/2 to 100/30. By being in this range, the turn-on voltage reduction effect and the hysteresis reduction effect can be obtained.

  As addition amount of metal compounds other than an aluminum compound and an aluminum compound, 0.1-100 weight part is preferable with respect to 100 weight part of polymers, and 1-30 weight part is more preferable. By being in this range, it is possible to obtain good FET characteristics, that is, high mobility, high on / off ratio, low turn-on voltage, and low hysteresis, and to obtain a homogeneous gate insulating material or gate insulating layer without agglomerates. Can do.

  As the polymer used in the present invention, polysiloxane, polyvinylphenol, polyimide, polyvinyl alcohol, polyvinyl chloride, polyethylene terephthalate, polyvinylidene fluoride, polysiloxane, polyvinylphenol, and the like can be used. Moreover, what copolymerized other polymers with these polymers, and what mixed can also be used. Any of these can be preferably used, but polysiloxane and polyvinylphenol are more preferably used. Furthermore, since it is preferable that the solvent resistance is excellent after the insulating layer is formed, it is preferable to react these polymers with a curing agent or a crosslinking agent to use the polymer as a crosslinked body.

  As an example of a polysiloxane suitable for the FET of the present invention, there is a polysiloxane having a silane compound represented by the general formula (1) and an epoxy group-containing silane compound represented by the general formula (2) as a copolymerization component.

The silane compound represented by the general formula (1) will be described.
R ¹ _m Si (OR ² ) _4-m (1)
Here, R ¹ represents hydrogen, an alkyl group, a cycloalkyl group, a heterocyclic group, an aryl group, a heteroaryl group or an alkenyl group, and when a plurality of R ¹ are present, each R ¹ may be the same or different. Good. R ² represents an alkyl group or a cycloalkyl group, and when a plurality of R ² are present, each R ² may be the same or different. m shows the integer of 1-3.

  The alkyl group is, for example, a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group, which is a substituent. It may or may not have. In the case of having a substituent, the additional substituent is not particularly limited, and examples thereof include an alkoxy group, an aryl group, a heteroaryl group, and the like, and these may further have a substituent. . Moreover, the number of carbon atoms of the alkyl group is not particularly limited, but is preferably 1 or more and 20 or less, more preferably 1 or more and 8 or less, from the viewpoint of availability and cost.

  The cycloalkyl group represents, for example, a saturated alicyclic hydrocarbon group such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, which may or may not have a substituent. In the case of having a substituent, the substituent is not particularly limited, and examples thereof include an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, and the like, and these substituents may further have a substituent. . The explanation regarding these substituents is common to the following descriptions. Although carbon number of a cycloalkyl group is not specifically limited, The range of 3-20 is preferable.

  The heterocyclic group refers to, for example, a group derived from an aliphatic ring having a non-carbon atom in the ring, such as a pyran ring, a piperidine ring, an amide ring, and the like, which has a substituent. It does not have to be. Although carbon number of a heterocyclic group is not specifically limited, The range of 2-20 is preferable.

  The aryl group refers to, for example, an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, a biphenyl group, an anthracenyl group, a phenanthryl group, a terphenyl group, and a pyrenyl group, which has a substituent. It does not have to be. Although carbon number of an aryl group is not specifically limited, The range of 6-40 is preferable.

  A heteroaryl group refers to an aromatic group having one or more atoms other than carbon in the ring, such as a furanyl group, a thiophenyl group, a benzofuranyl group, a dibenzofuranyl group, a pyridyl group, or a quinolinyl group. It may or may not have a substituent. Although carbon number of heteroaryl group is not specifically limited, The range of 2-30 is preferable.

  An alkenyl group shows the unsaturated aliphatic hydrocarbon group containing double bonds, such as a vinyl group, an allyl group, and a butadienyl group, and this may or may not have a substituent. Although carbon number of an alkenyl group is not specifically limited, The range of 2-20 is preferable.

  In addition, the alkoxy group mentioned above as a substituent represents a functional group obtained by substituting one of the ether bonds with an aliphatic hydrocarbon group, such as a methoxy group, an ethoxy group, or a propoxy group. It may or may not have a substituent. Although carbon number of an alkoxy group is not specifically limited, The range of 1-20 is preferable.

  By introducing the silane compound represented by the general formula (1) into the polysiloxane of the present invention, insulation and chemical resistance are improved while maintaining high transparency in the visible light region, and insulation that causes hysteresis. A gate insulating film with few traps in the film can be formed.

Further, when the general formula (1) at least one of m R ¹ in it is an aryl group or a heteroaryl group, increased flexibility of the gate insulating film is preferable because cracking can be prevented.

  Specific examples of the silane compound represented by the general formula (1) used in the present invention include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane. , Methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, hexyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane , Phenyltriethoxysilane, p-tolyltrimethoxysilane, benzyltrimethoxysilane, α-naphthyltrimethoxysilane, β-naphthyltrimethoxysilane, 3-aminopropyltri Ethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane , Methylvinyldimethoxysilane, methylvinyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylmethyl Diethoxysilane, cyclohexylmethyldimethoxysilane, 3-methacryloxypropyldimethoxysilane, octadecylmethyldimethoxysilane, trimethoxysilane, trifluoroethyl Trimethoxysilane, trifluoroethyltriethoxysilane, trifluoroethyltriisopropoxysilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane, heptadecafluorodecyltrimethoxysilane, hepta Decafluorodecyltriethoxysilane, heptadecafluorodecyltriisopropoxysilane, tridecafluorooctyltriethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriisopropoxysilane, trifluoroethylmethyldimethoxysilane, trifluoro Ethylmethyldiethoxysilane, trifluoroethylmethyldiisopropoxysilane, trifluoropropylmethyldi Toxisilane, trifluoropropylmethyldiethoxysilane, trifluoropropylmethyldiisopropoxysilane, heptadecafluorodecylmethyldimethoxysilane, heptadecafluorodecylmethyldiethoxysilane, heptadecafluorodecylmethyldiisopropoxysilane, tridecafluorooctyl Methyldimethoxysilane, tridecafluorooctylmethyldiethoxysilane, tridecafluorooctylmethyldiisopropoxysilane, trifluoroethylethyldimethoxysilane, trifluoroethylethyldiethoxysilane, trifluoroethylethyldiisopropoxysilane, trifluoropropyl Ethyldimethoxysilane, Tolyropropylethyldiethoxysilane, Trifluoropropylethyldiisopropoxy Sisilane, Heptadecafluorodecylethyldimethoxysilane, Heptadecafluorodecylethyldiethoxysilane, Heptadecafluorodecylethyldiisopropoxysilane, Tridecafluorooctylethyldiethoxysilane, Tridecafluorooctylethyldimethoxysilane, Tridecafluorooctyl Examples thereof include ethyl diisopropoxysilane and p-trifluorophenyltriethoxysilane.

Among the above silane compounds, m = 1 vinyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethylsilane, in order to increase crosslink density and improve chemical resistance and insulation properties. Methoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, hexyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, p-tolyltrimethoxysilane, benzyltrimethoxysilane , Α-naphthyltrimethoxysilane, β-naphthyltrimethoxysilane, trifluoroethyltrimethoxysilane, trimethoxysilane, and p-trifluorophenyltriethoxysilane are preferably used. . From the viewpoint of mass productivity, vinyltrimethoxysilane R ² is a methyl group, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, octadecyltrimethoxysilane, octadecyl trimethoxysilane, It is particularly preferable to use phenyltrimethoxysilane, p-tolyltrimethoxysilane, benzyltrimethoxysilane, α-naphthyltrimethoxysilane, β-naphthyltrimethoxysilane, trifluoroethyltrimethoxysilane, and trimethoxysilane.

  Moreover, it is mentioned as a preferable example to combine 2 or more types of silane compounds represented by General formula (1). Among these, a combination of a silane compound having an alkyl group and a silane compound having an aryl group or a heteroaryl group is particularly preferable because both high insulating properties and flexibility for preventing cracks can be achieved.

Next, the epoxy-containing silane compound represented by the general formula (2) will be described.
R ³ _n R ⁴ _l Si (OR ⁵ ) _4-n−1 (2)
Here, R ³ represents an alkyl group or a cycloalkyl group having one or more epoxy groups in a part of the chain, and when a plurality of R ³ are present, each R ³ may be the same or different. R ⁴ represents hydrogen, an alkyl group, a cycloalkyl group, a heterocyclic group, an aryl group, a heteroaryl group, or an alkenyl group. When a plurality of R ⁴ are present, each R ⁴ may be the same or different. R ⁵ represents an alkyl group or a cycloalkyl group, and when a plurality of R ⁵ are present, each R ⁵ may be the same or different. l represents an integer of 0 to 2, and n represents 1 or 2. However, l + n ≦ 3.

The alkyl group or cycloalkyl group having an epoxy group of R ³ in a part of the chain is a three-membered ring ether structure formed by combining two adjacent carbon atoms with one oxygen atom. An alkyl group or a cycloalkyl group.

The other descriptions of R ^{3 to} R ⁵ are the same as the descriptions of R ¹ and R ² above.

  By having the epoxy group-containing silane compound represented by the general formula (2), the polysiloxane used in the present invention can improve the coating property of the resist and organic semiconductor coating liquid on the gate insulating film, In addition, an excellent FET with small hysteresis can be obtained.

  Specific examples of the epoxy group-containing silane compound represented by the general formula (2) used in the present invention include γ-glycidoxypropyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. , Γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ-glycidoxypropyltriisopropoxysilane, β- (3,4-epoxycyclohexyl) ethyltriiso Propoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyl Methyldiethoxysilane, γ-glycidoxypro Pyrmethyldiisopropoxysilane, β- (3,4-epoxycyclohexyl) ethylmethyldiisopropoxysilane, γ-glycidoxypropylethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethylethyldimethoxysilane, γ -Glycidoxypropylethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethylethyldiethoxysilane, γ-glycidoxypropylethyldiisopropoxysilane, β- (3,4-epoxycyclohexyl) ethylethyl Examples thereof include diisopropoxysilane, β- (3,4-epoxycyclohexyl) propyltrimethoxysilane, and γ-glycidoxyethyltrimethoxysilane.

Among these, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) where n = 1 and l = 0 in order to increase crosslink density and improve chemical resistance and insulation properties Ethyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ-glycidoxypropyltriisopropoxysilane, β- (3,4-epoxycyclohexyl) It is preferable to use ethyltriisopropoxysilane, β- (3,4-epoxycyclohexyl) propyltrimethoxysilane, and γ-glycidoxyethyltrimethoxysilane. From the viewpoint of mass productivity, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) in which R ⁵ is a methyl group. It is particularly preferable to use propyltrimethoxysilane or γ-glycidoxyethyltrimethoxysilane.

  In addition to the silane compound represented by the general formula (1) or (2), the (a) polysiloxane of the present invention can contain other silane compounds as copolymerization components. Examples of other silane compounds include tetramethoxysilane and tetraethoxysilane.

  Moreover, content of the structural unit derived from the epoxy group containing silane compound represented by General formula (2) among polysiloxane is 0.00 with respect to all the structural units of the silane compound which is a copolymerization component of polysiloxane. It is preferable that it is 1 mol%-40 mol%. If it is 0.1 mol% or more, the favorable coating property which suppressed the repelling of the organic-semiconductor coating liquid can be obtained, and 1 mol% or more is more preferable. On the other hand, if it is 40 mol% or less, excellent FET characteristics with small hysteresis can be obtained, and 35 mol% or less is more preferable.

  The polysiloxane used in the present invention can be obtained, for example, by the following method. All silane compounds are dissolved in a solvent, and an acid catalyst and water are added thereto over 1 to 180 minutes, followed by hydrolysis at room temperature to 80 ° C. for 1 to 180 minutes. The temperature during the hydrolysis reaction is more preferably room temperature to 55 ° C. An epoxy group-containing polysiloxane can be obtained by heating this reaction liquid at 50 ° C. or higher and below the boiling point of the solvent for 1 to 100 hours to perform a condensation reaction. In this case, in order to form diol by adding water to the epoxy group of the epoxy group-containing silane compound represented by the general formula (2), in addition to the alkoxyl group and the equivalent amount of water in all the silane compounds, It is necessary to add more than an equivalent amount of water.

  Various conditions in the hydrolysis take into account the reaction scale, reaction vessel size, shape, etc., for example, by setting the acid concentration, reaction temperature, reaction time, etc., the physical properties suitable for the intended application Can be obtained.

  Acid catalysts used for the hydrolysis reaction of silane compounds include formic acid, oxalic acid, hydrochloric acid, sulfuric acid, acetic acid, trifluoroacetic acid, phosphoric acid, polyphosphoric acid, polyvalent carboxylic acid or anhydrides thereof, and ion exchange resins. A catalyst is mentioned. The content of the acid catalyst is preferably 0.05 parts by weight or more, and more preferably 0.1 parts by weight or more with respect to 100 parts by weight of the total silane compound that is a copolymer component of polysiloxane. Moreover, 10 weight part or less is preferable and 5 weight part or less is more preferable. If the content of the acid catalyst is 0.05 parts by weight or more, the hydrolysis reaction proceeds sufficiently, and if it is 10 parts by weight or less, a rapid reaction can be suppressed.

  The solvent used for the hydrolysis reaction is preferably an organic solvent, alcohols such as ethanol, propanol, butanol, 3-methyl-3-methoxy-1-butanol, glycols such as ethylene glycol and propylene glycol, and ethylene glycol monomethyl. Ether, ethers such as propylene glycol monomethyl ether, propylene glycol monobutyl ether and diethyl ether, ketones such as methyl isobutyl ketone and diisobutyl ketone, amides such as dimethylformamide and dimethylacetamide, ethyl acetate, ethyl cellosolve acetate, 3-methyl Acetates such as -3-methoxy-1-butanol acetate, aromatics or fats such as toluene, xylene, hexane, cyclohexane Other families hydrocarbons, .gamma.-butyrolactone, N- methyl-2-pyrrolidone, dimethyl sulfoxide and the like. The amount of the solvent is preferably in the range of 50 parts by weight to 500 parts by weight with respect to 100 parts by weight of the total silane compound that is a copolymer component of polysiloxane. If it is 50 parts by weight or more, rapid reaction can be suppressed, and if it is 500 parts by weight or less, hydrolysis can be sufficiently advanced.

  Moreover, as water used for a hydrolysis, ion-exchange water is preferable. The amount of water can be arbitrarily selected. In addition to the alkoxyl group and the equivalent mole of water in the silane compound, it is preferable to add the epoxy group and the equivalent mole of water or more. In order to increase the polymerization degree of the polysiloxane, reheating or addition of a base catalyst can be performed.

  Polysiloxane containing an epoxy group-containing silane compound used in the present invention as a copolymerization component is suitable as a gate insulating material because it has high insulation and chemical resistance and has few traps in the insulating film that cause hysteresis. Used for. Whether the polysiloxane contains an epoxy group-containing silane compound can be determined by combining various organic analysis methods such as elemental analysis, nuclear magnetic resonance analysis, and infrared spectroscopic analysis, singly or in combination.

  The gate insulating material of the present invention may contain one or more of the polysiloxanes of the present invention. In addition, one or more polysiloxanes of the present invention and one or more silane compounds may be mixed and used.

  The gate insulating material of the present invention preferably further contains a solvent having a boiling point of 110 to 200 ° C. at 1 atmosphere. Specific examples of such solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-butyl ether, propylene glycol mono t-butyl ether, and ethylene glycol. Ethers such as dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propyl acetate, butyl acetate, isobutyl acetate, 3-methoxybutyl acetate, 3 -Methyl-3-methoxybutyl acetate , Acetates such as methyl lactate, ethyl lactate and butyl lactate, ketones such as acetylacetone, methylpropylketone, methylbutylketone, methylisobutylketone, cyclopentanone and 2-heptanone, butyl alcohol, isobutyl alcohol, pentanol, Examples include alcohols such as 4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxybutanol, diacetone alcohol, and aromatic hydrocarbons such as toluene and xylene. When the boiling point is 110 ° C. or higher, the volatilization of the solvent is suppressed when the gate insulating material is applied, and the coating property is improved. When the boiling point is 200 ° C. or lower, the solvent remaining in the film is small, and the chemical resistance and A gate insulating film having excellent insulating properties can be obtained. More preferably, the boiling point is 130 ° C to 190 ° C. These solvents may be used alone or in combination of two or more.

  The preferred content of these solvents is 100 to 1500 parts by weight with respect to 100 parts by weight of polysiloxane. If it is 100 parts by weight or more, the volatilization of the solvent is suppressed and the applicability is good when applying the gate insulating material, and if it is 1500 parts by weight or less, there is little solvent remaining in the film, and chemical resistance and insulation are improved. An excellent gate insulating film can be obtained.

  When two or more solvents are used, it is possible to contain one or more low-boiling solvents having a boiling point of less than 110 ° C under atmospheric pressure or high-boiling solvents having a boiling point of more than 200 ° C under atmospheric pressure.

  The content of the curing agent contained in the gate insulating material of the present invention is preferably 0.1 to 100 parts by weight, more preferably 1 to 30 parts by weight with respect to 100 parts by weight of the polysiloxane. is there. If the content is 0.1 parts by weight or more, curing proceeds sufficiently and a gate insulating film having good chemical resistance and insulation can be obtained. On the other hand, if it is 30 parts by weight or less, the storage stability of the gate insulating material is good, and the insulating film is also very smooth and stable. In addition, as a hardening | curing agent used here, a thermal acid generator, a photo-acid generator, a metal alkoxide, a metal chelate etc. are used, More preferably, the metal compound of this invention is used.

  The gate insulating material of the present invention contains silane compounds represented by the general formulas (1) and (2) and hydrolysates of other silane compounds, that is, silanols. Silanol condenses into siloxane by the action of acid or base, but when condensation progresses during storage of the gate insulating material, the viscosity increases and causes the film thickness of the coating to change. When used as a gate insulating film, the change in film thickness causes variation in FET characteristics because the charge capacity in the insulating film stored when the gate voltage is applied, that is, in the ON state, changes. Therefore, it is preferable to suppress the increase in viscosity by controlling the pH of the gate insulating material to 2 to 7, preferably 3 to 6, which is a condition where the condensation rate of silanol is low. The pH can be examined by contacting and stirring with the same weight of water as the gate insulating material and measuring the pH of the aqueous phase. As the pH control method, a method of washing the gate insulating material with water, a method of removing excess acid or base with an ion exchange resin, and the like are preferably used.

  Moreover, the gate insulating material of this invention can contain a viscosity modifier, surfactant, a stabilizer, etc. as needed.

  Examples of the surfactant include a fluorine-based surfactant, a silicone-based surfactant, a polyalkylene oxide-based surfactant, and an acrylic surfactant.

  Specific examples of the fluorosurfactant include 1,1,2,2-tetrafluorooctyl (1,1,2,2-tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctyl. Hexyl ether, octaethylene glycol di (1,1,2,2-tetrafluorobutyl) ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, octapropylene glycol di (1 , 1,2,2-tetrafluorobutyl) ether, hexapropylene glycol di (1,1,2,2,3,3-hexafluoropentyl) ether, sodium perfluorododecylsulfonate, 1,1,2,2 , 8,8,9,9,10,10-decafluorododecane, 1,1,2,2,3,3-hexafluorodecane, N- [3- (Perful Looctanesulfonamido) propyl] -N, N′-dimethyl-N-carboxymethyleneammonium betaine, perfluoroalkylsulfonamidopropyltrimethylammonium salt, perfluoroalkyl-N-ethylsulfonylglycine salt, bis (N-par) phosphate Fluorooctylsulfonyl-N-ethylaminoethyl), monoperfluoroalkylethyl phosphate, and the like. Commercially available products include MegaFuck F142D, F172, F173, and F183 (above, manufactured by Dainippon Ink & Chemicals, Inc.), Ftop EF301, 303, and 352 (made by Shin-Akita Kasei Co., Ltd.). ), FLORARD FC-430, FC-431 (manufactured by Sumitomo 3M)), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.), BM-1000, BM-1100 (manufactured by Yusho Co., Ltd.), NBX-15, FTX-218 (manufactured by Neos Co., Ltd.), etc. be able to.

  Examples of the silicone surfactant include SH28PA, SH7PA, SH21PA, SH30PA, ST94PA (all manufactured by Toray Dow Corning Silicone Co., Ltd.), BYK-333 (manufactured by Big Chemie Japan Co., Ltd.), and the like. Examples of other surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene distearate and the like.

  The content of the surfactant is preferably 0.0001 to 1 part by weight with respect to 100 parts by weight of the polysiloxane. Two or more surfactants may be used simultaneously.

  Next, the gate insulating film of the present invention will be described in detail. The gate insulating film of the present invention can be obtained by heat-treating a coating film formed by applying the gate insulating material of the present invention in the range of 100 to 300 ° C.

  Examples of the method for applying the gate insulating material include known methods such as a spin coating method, a blade coating method, a slit die coating method, a screen printing method, a bar coater method, a mold method, a printing transfer method, a dip-up method, and an inkjet method. It is done. A gate insulating film can be formed by heat-treating a coating film obtained by applying and drying a gate insulating material on a glass substrate or a plastic substrate by the above-described application method. The thickness of the gate insulating film is preferably 0.01 to 5 μm, more preferably 0.05 to 1 μm. The heat treatment temperature is preferably in the range of 100 to 300 ° C. From the viewpoint of forming a gate insulating film on a plastic substrate, the temperature is more preferably 100 to 200 ° C.

  The gate insulating film of the present invention preferably has a dielectric constant of 3-50. The higher the dielectric constant, the smaller the turn-on voltage of the FET.

  Further, the gate insulating film of the present invention preferably has a low concentration of alkali metal or halogen ion. Specifically, both alkali metal and halogen ions are preferably 100 ppm or less of the gate insulating material, more preferably 1 ppm or less, and still more preferably 0.1 ppm or less.

  Next, an FET using the gate insulating film of the present invention will be described. The FET of the present invention is a field effect transistor having a gate electrode, a gate insulating layer, an active layer, a source electrode and a drain electrode, and the gate insulating layer contains the gate insulating film of the present invention.

  1 and 2 are schematic sectional views showing examples of the FET of the present invention. In FIG. 1, after a source electrode 5 and a drain electrode 6 are formed on a substrate 1 having a gate electrode 2 covered with a gate insulating layer 3 containing a gate insulating film of the present invention, an active layer is further formed thereon. 4 is formed. In FIG. 2, after the active layer 4 is formed on the substrate 1 having the gate electrode 2 covered with the gate insulating layer 3 containing the gate insulating film of the present invention, the source electrode 5 and the drain electrode 6 are further formed thereon. Is formed.

  Examples of the material used for the substrate 1 include inorganic materials such as silicon wafer, glass, and alumina sintered body, and organic materials such as polyimide, polyester, polycarbonate, polysulfone, polyethersulfone, polyethylene, polyphenylene sulfide, and polyparaxylene. It is done.

  Examples of materials used for the gate electrode 2, the source electrode 5, and the drain electrode 6 include conductive metal oxides such as tin oxide, indium oxide, and indium tin oxide (ITO), or platinum, gold, silver, copper, iron, Inorganic conductivity such as tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium, magnesium, palladium, molybdenum, metals such as amorphous silicon and polysilicon, alloys thereof, copper iodide, copper sulfide Examples include, but are not limited to, materials, polythiophene, polypyrrole, polyaniline, and a conductive polymer whose conductivity is improved by doping with iodine or the like, such as a complex of polyethylenedioxythiophene and polystyrenesulfonic acid. These electrode materials may be used alone, or a plurality of materials may be laminated or mixed.

  In the FET of the present invention, the gate insulating layer 3 contains the gate insulating film of the present invention. The gate insulating layer 3 is composed of a single layer or a plurality of layers. In the case of a plurality of layers, a plurality of gate insulating films of the present invention may be stacked, or a gate insulating film of the present invention and a known gate insulating film may be stacked. The known gate insulating film is not particularly limited, but is an inorganic material such as silicon oxide or alumina, an organic polymer material such as polyimide, polyvinyl alcohol, polyvinyl chloride, polyethylene terephthalate, polyvinylidene fluoride, polysiloxane, or polyvinylphenol, or A mixture of an inorganic material and an organic polymer material can be used.

  The film thickness of the gate insulating layer 3 is preferably 0.01 μm or more and 5 μm or less. By setting the film thickness in this range, it is easy to form a uniform thin film, and further, the source-drain current that cannot be controlled by the gate voltage can be suppressed, and the on / off ratio of the FET can be further increased. The film thickness can be measured by an atomic force microscope, an ellipsometry method, a surface roughness meter, a laser microscope, or the like.

  For the active layer 4, an organic semiconductor, a carbon nanotube, or a mixture or composite thereof is used.

  The organic semiconductor can be used regardless of the molecular weight as long as it has a semiconducting property, and a material having high carrier mobility can be preferably used. Further, those soluble in an organic solvent are more preferable, and the semiconductor layer can be easily formed by applying the solution to a glass substrate or a plastic substrate. Although the kind of organic semiconductor is not particularly limited, polythiophenes such as poly-3-hexylthiophene and polybenzothiophene, poly (2,5-bis (2-thienyl) -3,6-dipentadecylthieno [3,2 -B] thiophene), poly (4,8-dihexyl-2,6-bis (3-hexylthiophen-2-yl) benzo [1,2-b: 4,5-b ′] dithiophene), poly (4 Mainly thiophene units such as -octyl-2- (3-octylthiophen-2-yl) thiazole), poly (5,5'-bis (4-octylthiazol-2-yl) -2,2'-bithiophene) Compounds contained in the chain, polypyrroles, poly (p-phenylene vinylenes) such as poly (p-phenylene vinylene), polyanilines, polyacetylenes, polydiacetylenes , Polycarbazoles, polyfurans such as polyfuran and polybenzofuran, polyheteroaryls having a nitrogen-containing aromatic ring such as pyridine, quinoline, phenanthroline, oxazole and oxadiazole, anthracene, pyrene, naphthacene, pentacene, hexacene , Condensed polycyclic aromatic compounds such as rubrene, nitrogen-containing aromatic compounds such as furan, thiophene, benzothiophene, dibenzofuran, pyridine, quinoline, phenanthroline, oxazole, oxadiazole, 4,4′-bis (N- (3 Aromatic methyl derivatives represented by -methylphenyl) -N-phenylamino) biphenyl, biscarbazole derivatives such as bis (N-allylcarbazole) or bis (N-alkylcarbazole), pyrazoline derivatives, still Compounds, hydrazone compounds, metal phthalocyanines such as copper phthalocyanine, metal porphyrins such as copper porphyrin, distyrylbenzene derivatives, aminostyryl derivatives, aromatic acetylene derivatives, naphthalene-1,4,5,8-tetracarboxylic Examples thereof include condensed ring tetracarboxylic acid diimides such as acid diimide and perylene-3,4,9,10-tetracarboxylic acid diimide, and organic dyes such as merocyanine, phenoxazine and rhodamine. Two or more of these may be contained. Among these, an organic semiconductor having a thiophene skeleton is preferable.

  Another preferred form of the active layer 4 is a method using a composite of an organic semiconductor and a carbon nanotube (CNT). Adding CNT is preferably used as a means for improving the mobility of the organic semiconductor.

  The weight fraction of CNT contained in the composite of organic semiconductor and CNT is preferably 0.01 to 3% by weight with respect to the organic semiconductor in order to obtain semiconductor characteristics. When the content is less than 0.01% by weight, the effect of addition is small, and when the weight fraction is more than 3% by weight, the electrical conductivity of the composite increases excessively, making it unsuitable for use as a semiconductor layer. More preferably, it is 2% by weight or less. By making it 2% by weight or less, it becomes easy to obtain both high mobility and high on / off ratio.

  When a composite of an organic semiconductor and CNT is used for the FET, the length of the CNT is preferably at least shorter than the distance (channel length) between the source electrode and the drain electrode. When longer than this, it will cause a short circuit between electrodes. For this reason, it is preferable to use a CNT whose length is at least shorter than the distance (channel length) between the source electrode and the drain electrode, or to perform a step of making the CNT shorter than the channel length. In general, commercially available CNTs are distributed in length, and CNTs longer than the channel length may be included. Therefore, it is better to add a step of making the CNT shorter than the channel length, and it is possible to reliably prevent a short circuit between the electrodes. The average length of CNTs depends on the distance between the electrodes, but is preferably 5 μm or less, more preferably 1 μm or less.

  The diameter of the CNT is not particularly limited, but is 1 nm or more and 100 nm or less, more preferably 50 nm or less.

As the CNTs in the composite, CNTs having a conjugated polymer attached to at least a part of the surface can be used. Thereby, CNT can be more uniformly dispersed in the matrix (organic semiconductor), and a high on-off ratio can be realized with high mobility. The state where the conjugated polymer is attached to at least a part of the surface of the CNT means a state where a part or all of the surface of the CNT is covered with the conjugated polymer. The reason why the conjugated polymer can coat CNT is presumed to be that interaction occurs due to the overlap of π electron clouds derived from the respective conjugated structures. Whether or not the CNT is coated with the conjugated polymer can be determined by approaching the color of the conjugated polymer from the color of the uncoated CNT. Quantitatively, elemental analysis such as X-ray photoelectron spectroscopy (XPS) can identify the presence of deposits and the weight ratio of deposits to CNTs. A method in which CNT is added to and mixed with the conjugated polymer, (II) a method in which the conjugated polymer is dissolved in a solvent, and CNT is added and mixed therein, and (III) CNT is ultrasonicated in advance. Pre-dispersed with a method such as adding a conjugated polymer and mixing the mixture, (IV) adding a conjugated polymer and CNT in a solvent, irradiating the mixed system with ultrasonic waves, etc. Is mentioned. In the present invention, any method may be used, and any method may be combined.

  Conjugated polymers covering the above CNTs include polythiophene polymers, polypyrrole polymers, polyaniline polymers, polyacetylene polymers, poly-p-phenylene polymers, poly-p-phenylene vinylene polymers, etc. However, it is not particularly limited. As the polymer, those in which single monomer units are arranged are preferably used, but those obtained by block copolymerization or random copolymerization of different monomer units are also used. Further, graft-polymerized products can also be used. Among the above-mentioned polymers, in the present invention, a polythiophene polymer that is easily attached to CNT and easily forms a CNT composite is particularly preferably used.

  For the active layer 4, CNT having a conjugated polymer attached to at least a part of its surface can be used alone. For example, a good FET characteristic can be obtained by applying and drying this CNT dispersion on the active layer 4 to form a uniform network of the CNTs. CNTs with a conjugated polymer attached to at least a part of the surface can obtain good FET characteristics because the CNTs are in contact with each other at a contact point between CNTs or through a conjugated polymer excellent in semiconductor or conductivity. be able to.

  The active layer 4 can also be a single CNT. For example, the active layer 4 can be formed by transferring a CNT network synthesized by a chemical vapor deposition CVD method and deposited in a thin film state on a collection network. In this case, the FET characteristics can be obtained by controlling the density of the CNT network.

  For the active layer 4, CNTs having a dispersant such as a surfactant attached to at least a part of the surface can also be used. Compared to CNTs with conjugated polymers and CNTs with no surface-active agent attached to the surface, the FET characteristics are somewhat disadvantageous, but FETs can be formed by controlling the CNT network. it can.

  The active layer 4 can be formed by a dry method such as resistance heating vapor deposition, electron beam, sputtering, or CVD. From the viewpoint of manufacturing cost and adaptability to a large area, and the gate insulation of the present invention. In the gate insulating layer 3 including the film, it is preferable to use a coating method in order to make use of the advantage that the repelling of the coating liquid is suppressed. Specifically, a spin coating method, a blade coating method, a slit die coating method, a screen printing method, a bar coater method, a mold method, a printing transfer method, a dip pulling method, an ink jet method, etc. can be preferably used, and the coating thickness control The coating method can be selected according to the properties of the coating film to be obtained, such as the orientation control. Moreover, in order to reduce the influence on a plastic substrate, it is preferable that the heat processing after solution application are 220 degrees C or less.

  In the formed FET, the current flowing between the source electrode and the drain electrode can be controlled by changing the gate voltage. The mobility of the FET can be calculated using the following equation (a).

μ = (δId / δVg) L · D / (W · ε r · ε · Vsd) (a)
However Id is the current between the source and drain, Vsd is the voltage between the source and the drain, Vg is the thickness of the gate voltage, D is the insulating layer, L is the channel length, W is the channel width, epsilon _r is the relative dielectric gate insulating layer The rate, ε, is the dielectric constant of vacuum (8.85 × 10 ⁻¹² F / m).

  Further, the on / off ratio can be obtained from the ratio of the value of Id (on current) at a certain negative gate voltage to the value of Id (off current) at a certain positive gate voltage.

Hysteresis is the difference between the gate voltage Vg ¹ at Id = 10 ⁻⁸ when Vg is applied from positive to negative and the gate voltage Vg ² at Id = 10 ⁻⁸ when Vg is applied from negative to positive. The absolute value | Vg ¹ −Vg ² |

  The gate insulating material and the gate insulating film of the present invention can be advantageously used in the production of various devices such as thin film field effect transistors, photovoltaic elements, and switching elements.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited by these Examples.

Example 1
(1) Preparation of CNT complex dispersion 0.10 g of poly-3-hexylthiophene (Aldrich, regioregular, number average molecular weight (Mn): 13000, hereinafter referred to as P3HT), which is a conjugated polymer, was added to 5 ml of chloroform. In addition to the flask which entered, the chloroform solution of P3HT was obtained by ultrasonically stirring in an ultrasonic cleaning machine (US-2 manufactured by Inoue Seieido Co., Ltd., output 120 W). Subsequently, this solution was taken in a dropper, and 0.5 ml was dropped into a mixed solution of 20 ml of methanol and 10 ml of 0.1N hydrochloric acid to perform reprecipitation. The solid P3HT was collected by filtration with a 0.1 μm pore size membrane filter (PTFE: tetrafluoroethylene), rinsed well with methanol, and then the solvent was removed by vacuum drying. Further, dissolution and reprecipitation were performed again to obtain 90 mg of reprecipitation P3HT.

  Add 1.0 mg of single-walled CNT (single-walled carbon nanotubes manufactured by CNI, purity 95%) and 1.0 mg of the above P3HT into 10 ml of chloroform, and ultrasonically homogenizer (VCX manufactured by Tokyo Rika Kikai Co., Ltd.) -500) for 30 minutes with an output of 250 W. When the ultrasonic irradiation was performed for 30 minutes, the irradiation was stopped once, 1.0 mg of the above P3HT was added, and further ultrasonic irradiation was performed for 1 minute, whereby the CNT composite dispersion A (CNT concentration 0.1 g / l) was obtained.

  In order to examine whether or not P3HT was adhered to the CNT in the CNT complex dispersion A, 5 ml of the dispersion A was filtered using a membrane filter, and CNT was collected on the filter. The collected CNTs were quickly transferred onto a silicon wafer before the solvent was dried to obtain dried CNTs. When this CNT was subjected to elemental analysis using X-ray photoelectron spectroscopy (XPS), sulfur element contained in P3HT was detected. Therefore, it was confirmed that P3HT was adhered to the CNT in the CNT composite dispersion A.

  After adding 5 ml of o-dichlorobenzene (boiling point 180 ° C., hereinafter referred to as o-DCB) to the CNT complex dispersion A, chloroform as a low boiling point solvent was distilled off using a rotary evaporator. Substitution with DCB gave CNT composite dispersion B. Next, the dispersion B was filtered using a membrane filter (pore size: 3 μm, diameter: 25 mm, Omnipore membrane manufactured by Millipore) to remove CNTs having a length of 10 μm or more. The obtained filtrate was diluted by adding o-DCB to obtain a CNT composite dispersion C (CNT concentration 0.06 g / l with respect to the solvent).

(2) Preparation of polymer solution for insulating layer (gate insulating material) 61.29 g (0.45 mol) of methyltrimethoxysilane, 12.31 g of β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (0.05) Mol) and 99.15 g (0.5 mol) of phenyltrimethoxysilane were dissolved in 203.36 g of propylene glycol monobutyl ether (boiling point: 170 ° C.), and 54.90 g of water and 0.864 g of phosphoric acid were stirred. Added while. The obtained solution was heated at a bath temperature of 105 ° C. for 2 hours, the internal temperature was raised to 90 ° C., and a component mainly composed of methanol as a by-product was distilled out. Next, the bath was heated at 130 ° C. for 2.0 hours, the internal temperature was raised to 118 ° C., and a component mainly composed of water and propylene glycol monobutyl ether was distilled off, and then cooled to room temperature, and the solid content concentration was 26.0 wt. % Polymer solution A was obtained.

  50 g of the obtained polymer solution A was weighed, mixed with 16.6 g of propylene glycol monobutyl ether (boiling point 170 ° C.), stirred at room temperature for 2 hours, and polymer solution B (solid content concentration 19.5 wt%) was obtained. Obtained. Further, in the polymer solution B, zirconia tetrakis acetylacetonate (hereinafter referred to as Zr (acac) 4) 0.65 g (5% by weight with respect to polymer solids) as a curing agent, aluminum trisacetylacetonate (hereinafter referred to as 0.65 g of Al (acac) 3) was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution C (gate insulating material C).

(3) Fabrication and evaluation of FET The FET of FIG. 1 was fabricated. A gate electrode 2 was formed on a glass substrate 1 (thickness 0.7 mm) by vacuum evaporation of chromium with a thickness of 5 nm and then gold with a thickness of 50 nm through a metal mask by a resistance heating method. Next, the polymer solution C prepared in the above (2) is spin-coated (2000 rpm × 30 seconds) on the glass substrate on which the gate electrode is formed, and the obtained coating film is heated at 200 ° C. for 1 hour in a nitrogen stream. By processing, a gate insulating film having a thickness of 600 nm was obtained, and the gate insulating layer 3 was formed. On the substrate on which the gate insulating layer was formed, gold was vacuum-deposited so as to have a thickness of 50 nm. Next, a positive resist solution was dropped and applied using a spinner, and then dried on a hot plate at 90 ° C. to form a resist film. The obtained resist film was irradiated with ultraviolet rays through a photomask using an exposure machine. Subsequently, the substrate was immersed in an alkaline aqueous solution, the ultraviolet irradiation part was removed, and a resist film patterned into an electrode shape was obtained. The obtained substrate was immersed in a gold etching solution (manufactured by Aldrich, Gold etchant, standard), and the gold in the portion where the resist film was removed was dissolved and removed. The obtained substrate was immersed in acetone, the resist was removed, washed with pure water, and dried on a hot plate at 100 ° C. for 30 minutes. Thus, a gold source / drain electrode having an electrode width (channel width) of 0.2 mm, an electrode interval (channel length) of 20 μm, and a thickness of 50 nm was obtained.

  Next, the CNT composite dispersion C prepared in (1) above is applied onto the substrate on which the electrodes are formed using an inkjet method, and is heat-treated at 150 ° C. for 30 minutes in a nitrogen stream on a hot plate. Thus, an FET having the CNT composite dispersion film as a channel layer was produced. At this time, a simple discharge experiment set PIJL-1 (manufactured by Cluster Technology Co., Ltd.) was used for the ink jet apparatus.

Next, the source-drain current (Id) -source-drain voltage (Vsd) characteristics when the gate voltage (Vg) of the FET was changed were measured. The measurement was performed in the atmosphere using a semiconductor characteristic evaluation system 4200-SCS type (manufactured by Keithley Instruments Co., Ltd.). When the mobility in the linear region was determined from the change in the value of Id at Vsd = -5V when Vg was changed from +30 to -30V, it was 0.32 cm ² / V · sec. Further, when the on / off ratio was determined from the ratio between the maximum value and the minimum value of Id at this time, it was 8 × 10 ⁵ . In the IV curve when Vg was swept from +30 to -30V, the value Von of Vg at which the current I suddenly rose was read and found to be + 10V. Further, when the hysteresis was calculated from the absolute value | Vg ¹ −Vg ² | of the gate voltage difference between the return and return at Id = 10 ⁻⁸ , it was + 1V.

Example 2
54.47 g (0.40 mol) of methyltrimethoxysilane, 24.62 g (0.10 mol) of β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 99.15 g (0.5 of phenyltrimethoxysilane) Mol), except that the blending ratio was changed to 161.38 g of propylene glycol monobutyl ether, the same operation as in Example 1 was carried out to obtain a polymer solution D having a solid content concentration of 45.0 wt%. 25 g of the obtained polymer solution D was weighed, mixed with 25 g of propylene glycol monobutyl ether (boiling point 170 ° C.), and stirred at room temperature for 2 hours to obtain a polymer solution E (solid content concentration 22.5 wt%). . Further, 0.56 g (5% by weight based on the polymer solid content) of Zr (acac) 4 as a curing agent and 0.56 g of Al (acac) 3 were added to the polymer solution D and stirred at room temperature for 2 hours. The polymer solution F (gate insulating material F) was obtained.

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution F was used, and the evaluation was performed. As a result, the mobility was 0.36 cm ² / V · sec, the on / off ratio was 8 × 10 ⁵ , Von. Was + 10V, and the hysteresis was + 1V.

Example 3
In polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, 0.56 g of Zr (acac) 4 as a curing agent (5% by weight with respect to polymer solids) and Al (acac) ) 3 0.56 g and magnesium bisacetylacetonate (hereinafter referred to as Mg (acac) 2) 0.56 g were added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution G (gate insulating material G). Obtained.

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution G was used, and the mobility was 0.15 cm ² / V · sec, the on / off ratio was 2 × 10 ⁵ , Von. Was + 10V, and the hysteresis was + 2V.

Example 4
In the polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, 0.56 g of the curing agent Al (acac) 3 (5% by weight based on the polymer solid content) and indium trisacetyl 0.56 g of acetonate (In (acac) 3) was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution H (gate insulating material H).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution H was used, and evaluation was performed. As a result, the mobility was 0.18 cm ² / V · sec, the on / off ratio was 1 × 10 ⁵ , Von Was + 8V, and the hysteresis was -2V.

Example 5
In polymer solution E having a solid content concentration of 22.5 wt% described in Example 2 above, 0.56 g (5 wt% based on the polymer solid content) of Al (acac) 3 as a curing agent, and lanthanum trisacetyl 0.56 g of acetonate (La (acac) 3) was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution I (gate insulating material I).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution I was used, and evaluated. As a result, the mobility was 0.20 cm ² / V · sec, the on / off ratio was 1 × 10 ⁵ , Von Was + 10V, and the hysteresis was + 5V.

Example 6
In the polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, 0.56 g (5% by weight with respect to the polymer solid content) of the curing agent Al (acac) 3 and Mg (acac And 0.56 g of 2 was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution J (gate insulating material J).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution J was used, and when evaluated, the mobility was 0.12 cm ² / V · sec, the on / off ratio was 2 × 10 ⁵ , Von Was + 12V, and the hysteresis was + 2V.

Example 7
In the polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, 0.56 g (5% by weight with respect to the polymer solid content) of the curing agent Al (acac) 3 and zinc bisacetyl 0.56 g of acetonate (Zn (acac) 2) was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution K (gate insulating material K).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution K was used, and the mobility was 0.19 cm ² / V · sec, the on / off ratio was 1 × 10 ⁵ , Von. Was + 12V, and the hysteresis was + 2V.

Example 8
In the polymer solution E having a solid content concentration of 22.5 wt% described in Example 2 above, 0.56 g (5 wt% based on the polymer solid content) of the curing agent Al (acac) 3 and copper bisacetyl 0.56 g of acetonate (Cu (acac) 2) was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution L (gate insulating material L).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution L was used, and evaluation was performed. As a result, the mobility was 0.11 cm ² / V · sec, the on / off ratio was 1 × 10 ⁵ , Von Was + 12V, and the hysteresis was + 5V.

Example 9
In polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, 0.56 g of curing agent Al (acac) 3 (5% by weight with respect to polymer solids), calcium bisacetyl 0.56 g of acetonate (Ca (acac) 2) was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution M (gate insulating material M).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution M was used, and evaluated. As a result, the mobility was 0.12 cm ² / V · sec, the on / off ratio was 2 × 10 ⁵ , Von Was + 14V, and the hysteresis was + 5V.

Example 10
In the polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, 0.56 g (5% by weight with respect to the polymer solids) of the curing agent Al (acac) 3 and titanium bis ( 0.56 g of isopropyloxy) bis (acetylacetonate) (Ti (acac) 2 (OiPr) 2) was added and dissolved by stirring at room temperature for 2 hours to obtain a polymer solution N (gate insulating material N).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution N was used, and the evaluation was performed. As a result, the mobility was 0.31 cm ² / V · sec, the on / off ratio was 2 × 10 ⁵ , Von Was + 12V, and the hysteresis was + 4V.

Example 11
Using WP-BT1 obtained in Synthesis Example 1 below instead of P3HT as a conjugated polymer for forming the CNT composite, the same operation as in Example 1 was performed to obtain a CNT composite dispersion D. An FET was prepared in the same manner as in Example 2 except that the CNT composite dispersion D was used instead of the CNT composite dispersion C, and the characteristics were measured. The mobility was 0.54 cm ² / V · sec. The on / off ratio was 1 × 10 ⁵ , Von was +10 V, and the hysteresis was +2 ^V.

Synthesis example 1
A conjugated polymer [WP-BT1] represented by the following formula was synthesized as follows.

  2.0 g of 4,7-dibromo-2,1,3-benzothiadiazole and 4.3 g of bis (pinacolato) diboron are added to 40 ml of 1,4-dioxane, and 4.0 g of potassium acetate, [bis ( Diphenylphosphino) ferrocene] dichloropalladium (1.0 g) was added, and the mixture was stirred at 80 ° C. for 8 hours. 200 ml of water and 200 ml of ethyl acetate were added to the resulting solution, and the organic layer was separated, washed with 400 ml of water, and dried over magnesium sulfate. The resulting solution was purified by column chromatography (filler: silica gel, eluent: dichloromethane / ethyl acetate) and 4,7-bis (4,4,5,5-tetramethyl- [1,3,2] 1.3 g of dioxaborolan-2-yl) -2,1,3-benzothiadiazole was obtained.

  Next, 18.3 g of 2-bromo-3-hexylthiophene was dissolved in 250 ml of tetrahydrofuran and cooled to -80 ° C. After adding 45 ml of n-butyllithium (1.6M hexane solution), the temperature was raised to −50 ° C. and cooled again to −80 ° C. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (18.6 ml) was added, the temperature was raised to room temperature, and the mixture was stirred under a nitrogen atmosphere for 6 hours. 200 ml of 1N aqueous ammonium chloride and 200 ml of ethyl acetate were added to the resulting solution, and the organic layer was separated, washed with 200 ml of water, and then dried over magnesium sulfate. The resulting solution was purified by column chromatography (filler: silica gel, eluent: hexane / dichloromethane) to give 2- (4,4,5,5-tetramethyl- [1,3,2] dioxaborolan-2-yl. ) -3-hexylthiophene (16.66 g) was obtained.

  Next, 2.52 g of the 2-bromo-3-hexylthiophene and the 2- (4,4,5,5-tetramethyl- [1,3,2] dioxaborolan-2-yl) -3-hexylthiophene 3.0 g was added to 100 ml of dimethylformamide, 13 g of potassium phosphate and 420 mg of [bis (diphenylphosphino) ferrocene] dichloropalladium were added under a nitrogen atmosphere, and the mixture was stirred at 90 ° C. for 5 hours. 200 ml of water and 100 ml of hexane were added to the resulting solution, and the organic layer was separated, washed with 400 ml of water, and dried over magnesium sulfate. The resulting solution was purified by column chromatography (filler: silica gel, eluent: hexane) to obtain 2.71 g of 3,3′-dihexyl-2,2′-bithiophene.

  Next, 2.71 g of the above 3,3′-dihexyl-2,2′-bithiophene was dissolved in 8 ml of dimethylformamide, a solution of N-bromosuccinimide 2.88 g in dimethylformamide (16 ml) was added, and 5 ° C. to 10 ° C. For 9 hours. 150 ml of water and 100 ml of hexane were added to the resulting solution, the organic layer was separated, washed with 300 ml of water, and dried over magnesium sulfate. The resulting solution was purified by column chromatography (filler: silica gel, eluent: hexane) to obtain 3.76 g of 5,5'-dibromo-3,3'-dihexyl-2,2'-bithiophene.

  Next, 3.76 g of the above 5,5′-dibromo-3,3′-dihexyl-2,2′-bithiophene and the above 2- (4,4,5,5-tetramethyl- [1,3,2] ] 4.71 g of dioxaborolan-2-yl) -3-hexylthiophene was added to 70 ml of dimethylformamide, and 19.4 g of potassium phosphate and 310 mg of [bis (diphenylphosphino) ferrocene] dichloropalladium were added under a nitrogen atmosphere at 90 ° C. For 9 hours. Water (500 ml) and hexane (200 ml) were added to the resulting solution, and the organic layer was separated, washed with water (300 ml), and dried over magnesium sulfate. The resulting solution was purified by column chromatography (filler: silica gel, eluent: hexane), and 3,4 ′, 3 ″, 3 ″ ′-tetrahexyl-2,2 ′: 5 ′, 2 ′. ': 5 ″, 2 ′ ″-Quarterthiophene 4.24g was obtained.

  Next, 520 mg of the above 3,4 ′, 3 ″, 3 ′ ″-tetrahexyl-2,2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarterthiophene is dissolved in 20 ml of chloroform. Then, a solution of 280 mg of N-bromosuccinimide in dimethylformamide (10 ml) was added and stirred at 5 ° C. to 10 ° C. for 5 hours. To the obtained solution, 150 ml of water and 100 ml of dichloromethane were added, and the organic layer was separated, washed with 200 ml of water, and dried over magnesium sulfate. The resulting solution was purified by column chromatography (filler: silica gel, eluent: hexane), and 5,5 ′ ″-dibromo-3,4 ′, 3 ″, 3 ′ ″-tetrahexyl-2. , 2 ′: 5 ′, 2 ″: 5 ″, 2 ′ ″-quarterthiophene was obtained in an amount of 610 mg.

  Next, 280 mg of the above 4,7-bis (4,4,5,5-tetramethyl- [1,3,2] dioxaborolan-2-yl) -2,1,3-benzothiadiazole and the above 5,5 '' '-Dibromo-3,4', 3 '', 3 '' '-tetrahexyl-2,2': 5 ', 2' ': 5' ', 2' ''-quarterthiophene 596 mg in 30 ml of toluene Dissolved in. 10 ml of water, 1.99 g of potassium carbonate, 83 mg of tetrakis (triphenylphosphine) palladium (0) and 1 drop of Aliquat 336 were added thereto, and the mixture was stirred at 100 ° C. for 20 hours under a nitrogen atmosphere. 100 ml of methanol was added to the resulting solution, and the generated solid was collected by filtration and washed with methanol, water, acetone, and hexane in this order. The obtained solid was dissolved in 200 ml of chloroform, passed through a silica gel short column (eluent: chloroform), concentrated to dryness, then washed with methanol, acetone and methanol in this order to obtain a conjugated polymer [WP-BT1]. 480 mg was obtained. As a result of GPC measurement, the weight average molecular weight was 47698, the number average molecular weight was 13555, and the polymerization degree n was 45.6.

Example 12
10 g of polyvinylphenol (manufactured by Aldrich, molecular weight Mw 20000), 5 g of poly (melamine-co-formaldehyde) methylated (manufactured by Aldrich, butanol 84% solution), 100 g of propylene glycol monobutyl ether, 3 g of Al (acac) 3 and Zr ( A solution obtained by mixing 0.3 g of (acac) 4 was stirred at room temperature for 30 minutes to obtain a polymer solution O (gate insulating material O).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution O and the CNT composite dispersion D were used, and the mobility was 0.08 cm ² / V. · sec, on-off ratio is 1 × ¹⁰ 5, Von is + 11V, hysteresis was + 5V.

Comparative Example 1
To the polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, only the curing agent Zr (acac) 4 was added, and 0.56 g (5% by weight based on the polymer solid content) was added. Then, the mixture was dissolved by stirring at room temperature for 2 hours to obtain a polymer solution P (gate insulating material P).

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution P was used, and when evaluated, the mobility was 0.35 cm ² / V · sec, the on / off ratio was 1 × 10 ⁶ , Von Was + 25V, and the hysteresis was + 10V.

Comparative Example 2
In the polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, the curing agent is only Al (acac) 3, and 0.56 g (5% by weight based on the polymer solid content) is added. The polymer solution Q (gate insulating material Q) was obtained by stirring at room temperature for 2 hours to dissolve.

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution Q was used, and when evaluated, the mobility was 0.80 cm ² / V · sec, the on / off ratio was 4 × 10 ⁷ , Von Was + 3V, and the hysteresis was −15V.

Comparative Example 3
To the polymer solution E having a solid content concentration of 22.5% by weight described in Example 2 above, the curing agent is only Mg (acac) 2 and 0.56 g (5% by weight based on the polymer solid content) is added. The polymer solution R (gate insulating material R) was obtained by stirring at room temperature for 2 hours to dissolve.

An FET was prepared by performing the same operation as in Example 1 except that the polymer solution R was used, and evaluated. As a result, the mobility was 0.08 cm ² / V · sec, the on / off ratio was 8 × 10 ³ , Von. Was + 12V, and the hysteresis was + 25V.

Comparative Example 4
An FET was prepared by performing the same operation as in Example 1 except that the polymer solution E to which no curing agent was added was used as the gate insulating material E, and the mobility was 0.02 cm ² / V. -Sec, ON / OFF ratio was 3 * 10 < ⁴ >, Von was + 18V, and the hysteresis was + 10V.

Comparative Example 5
A solution prepared by mixing 10 g of polyvinylphenol (manufactured by Aldrich, molecular weight Mw 20000), 5 g of poly (melamine-co-formaldehyde) methylated (manufactured by Aldrich, 84% butanol solution), and 100 g of propylene glycol monobutyl ether was stirred at room temperature for 30 minutes. Thus, a polymer solution S (gate insulating material S) was obtained. An FET was prepared by performing the same operation as in Example 12 except that the polymer solution S was used, and evaluation was performed. As a result, the mobility was 0.07 cm ² / V · sec, the on / off ratio was 8 × 10 ⁴ , Von. Was + 25V, and the hysteresis was + 20V.

  The gate insulating material and gate insulating film of the present invention are used for a field effect transistor that can be used for a smart card, a security tag, a transistor array for a flat panel display, and the like.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Gate electrode 3 Gate insulating layer 4 Active layer 5 Source electrode 6 Drain electrode

Claims (6)

A gate insulating material containing a polymer and a metal compound, wherein the metal compound is a metal chelate compound or a metal alkoxide compound, and a magnesium compound, a zinc compound, a copper compound, an indium compound, a lanthanium compound, a manganese compound, a calcium compound, A gate insulating material comprising one or more of a tin compound, a titanium compound, a zirconium compound, a hafnium compound, and an aluminum compound. The gate insulating material according to claim 1 Symbol placement polymer is a polysiloxane. A gate insulating film obtained by heat-treating a coating film formed by applying the gate insulating material according to claim 1 in a range of 100 to 300 ° C. A field effect transistor comprising a gate insulating layer, a gate electrode, an active layer, a source electrode, and a drain electrode containing the gate insulating film according to claim 3 . The field effect transistor according to claim 4, wherein the active layer contains at least carbon nanotubes. 6. The field effect transistor according to claim 5, wherein the carbon nanotube has a conjugated polymer attached to at least a part of its surface.

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