WO2011033749A1

WO2011033749A1 - Thin-film transistor

Info

Publication number: WO2011033749A1
Application number: PCT/JP2010/005548
Authority: WO
Inventors: 菅原孝宜; 中村浩昭; 齊藤雅俊; 彦坂高明
Original assignee: 出光興産株式会社
Priority date: 2009-09-18
Filing date: 2010-09-10
Publication date: 2011-03-24
Also published as: JPWO2011033749A1; TW201123575A

Abstract

Disclosed is a thin-film transistor wherein at least three terminals, namely a gate electrode, source electrode and drain electrode, an insulator layer, and a semiconductor layer are provided on a substrate, and the current between the source and drain is controlled by application of voltage to the gate electrode. The insulating layer is a layer which has been laminated by means of a coating method and which contains polycarbonate that has solubility with respect to at least one solvent selected from tetrahydrofuran, cyclohexanone and toluene of at least 5 wt%, and that comprises repeating units represented by formula (I).

Description

Thin film transistor

The present invention relates to a thin film transistor. More specifically, the present invention relates to an organic thin film transistor having an insulator layer containing a specific material.

Thin film transistors (TFTs) are widely used as display switching elements for liquid crystal display devices and the like.
Conventionally, this TFT has been manufactured using amorphous or polycrystalline silicon. However, a CVD (Chemical Vapor Deposition) apparatus used for manufacturing a TFT using silicon is very expensive and uses a TFT. Increasing the size of the display device or the like has a problem that the manufacturing cost is significantly increased. In addition, since the process of forming amorphous or polycrystalline silicon is performed at a very high temperature, there is a problem that the types of materials that can be used as a substrate are limited, and a lightweight resin substrate cannot be used.

In order to solve the above problems, TFTs using organic substances have been proposed instead of amorphous and polycrystalline silicon. As a film forming method for forming a TFT using an organic material, it is known that a film can be formed by a vacuum vapor deposition method and a coating method. In particular, by using a coating method, an element is manufactured while suppressing an increase in manufacturing cost. The process temperature required for film formation can be made relatively low. For this reason, TFTs using organic substances have the advantage that there are few restrictions on the selection of materials that can be used for the substrate.
As for TFTs using organic substances, many reports have been made (for example, Non-Patent Documents 1 and 2), and their practical application is expected.

Since the electric conduction in the TFT is caused by the electric field induced charge at the interface of the insulating film, the electric conduction is strongly influenced by the insulating film.
Non-Patent Document 3 discloses that organic molecules in adjacent organic semiconductor thin films are oriented perpendicular to the substrate by using a polycarbonate layer made of bisphenol A as a gate insulator layer by spin coating with a chloroform solution. is doing. Patent Document 1 discloses that an organic transistor having flexibility, high mobility, and high on / off ratio can be realized by selecting an appropriate insulating film such as polycarbonate for the supporting substrate. An insulating film is formed by a spin coating process using a chloroform solution.

The conventionally known bisphenol A type polycarbonate has good solubility in a halogen-based solvent, but the solubility in a non-halogen-based solvent such as tetrahydrofuran (THF) is not sufficient. In addition, since a halogen atom derived from a solvent remains in an element manufactured using a halogen-based solvent, this has an adverse effect on transistor performance, and there is a problem of inducing deterioration of characteristics at the use stage of the manufactured element. there were.

In addition, there is a problem that the halogen-based solvent has a heavy load on the environment and the human body. Polycarbonate using bisphenol A as a raw material disclosed in Patent Literature 1, Non-Patent Literature 3 and the like has a problem that it cannot be applied to a coating process using a non-halogen solvent because of its low solubility in a non-halogen solvent.

JP 2004-128469 A

An object of the present invention is to provide a thin film transistor having an insulating layer that can be stacked by a coating method using a non-halogen solvent, a high response speed (driving speed), a large on / off ratio, and excellent transistor characteristics. It is to be.
Another object of the present invention is to provide a thin film transistor capable of reducing deterioration with time and reducing environmental load.

The present invention has been made to solve the above problems, and a polycarbonate resin layer having a specific structure can be formed by a coating process using a non-halogen solvent, and is used as a gate insulator layer. The thin film transistor was found to have a high response speed (driving speed) and a high on / off ratio, thereby completing the present invention.

According to the present invention, the following thin film transistor is provided.
1. In a thin film transistor in which at least three terminals of a gate electrode, a source electrode and a drain electrode, an insulator layer and a semiconductor layer are provided on a substrate, and a source-drain current is controlled by applying a voltage to the gate electrode.
The insulator layer is a layer laminated by a coating method and has a solubility in at least one solvent selected from tetrahydrofuran, cyclohexanone and toluene of 5% by weight or more, and is represented by the following formula (I) A thin film transistor containing a polycarbonate composed of units.

(In the formula, Ar is a divalent aromatic group.)
2. 2. The thin film transistor according to 1, wherein Ar in the formula (I) is a bonding group represented by the following formula (1) or (2).

(In the formula, R ¹ and R ² are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(Wherein R ³ and R ⁴ are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom.
X represents —O—, —S—, —SO—, —SO ₂ —, —CO—, 9,9-fluorenylidene group, represented by the following formula (2a), (2b), (2c), or (2d) It is a linking group represented. )

(Wherein R ⁵ and R ⁶ are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R ⁵ and R ⁶ are bonded to each other. A cycloalkylidene group having 4 to 12 carbon atoms may be formed.)

(In the formula, each R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and at least one of R is an alkyl group having 1 to 3 carbon atoms.)

(The linking group represented by the formula (2c) may be o-, m-, or p-)

(In the formula, two of R ⁷ to R ¹² are bonding groups, and R ⁷ to R ¹² that are bonding groups are each a single bond or an alkylene group, and each of R ⁷ to R ¹² that is not a bonding group is It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
3. 3. The thin film transistor according to 1 or 2, wherein Ar in the formula (I) is a bonding group represented by the following formula (3) having an asymmetric structure.

(Wherein R ¹³ and R ¹⁴ are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom.
R ¹⁵ and R ¹⁶ are different from each other, and each is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. )
4). Carbon in which Ar in Formula (I) is a linking group represented by Formula (2), X is a linking group represented by Formula (2a), and R ⁵ and R ⁶ are bonded to each other. 3. The thin film transistor according to 2, which is a cycloalkylidene group of formula 4-12.
5. 3. The thin film transistor according to 1 or 2, wherein Ar in the formula (I) is a bonding group represented by the following formula (4).

(In the formula, X is the same as the formula (2).
R ¹⁷ and R ¹⁸ are each an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. )
6). 2. The thin film transistor according to 1, wherein Ar in the formula (I) is a bonding group represented by the following formula (5).

(Wherein R ¹⁹ is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and R ²⁰ is an aryl group having 6 to 12 carbon atoms, respectively. And an aliphatic hydrocarbon group having 4 to 12 carbon atoms.)
7). Ar in the formula (I) has a linking group represented by the following formulas (6a), (6b) and (6c), and the number of these linking groups is (6a + 6c) / (6a + 6b + 6c) = 0.05-0. 1. The thin film transistor according to 1, which satisfies .95.

(In the formula, X is the same as the formula (2).
R is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. )
8). In a thin film transistor in which at least three terminals of a gate electrode, a source electrode and a drain electrode, an insulator layer and a semiconductor layer are provided on a substrate, and a source-drain current is controlled by applying a voltage to the gate electrode.
The insulator layer is a layer laminated by a coating method and has a solubility in at least one solvent selected from tetrahydrofuran, cyclohexanone and toluene of 5% by weight or more, and is represented by the following formula (II) A thin film transistor containing a polycarbonate comprising a copolymer of a unit and a repeating unit represented by the following formula (III).

(In the formula, Ar ² and Ar ³ are each a linking group represented by the following formula (1) or (2), and Ar ² and Ar ³ are linking groups different from each other.)

(The linking group represented by the formula (2c) may be o-, m-, or p-)

(In the formula, two of R ⁷ to R ¹² are bonding groups, and R ⁷ to R ¹² that are bonding groups are each a single bond or an alkylene group, and each of R ⁷ to R ¹² that is not a bonding group is It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
9. 9. The thin film transistor according to any one of 1 to 8, wherein the polycarbonate has a solubility in tetrahydrofuran of 7% by weight or more.
10. 10. The organic thin film transistor according to any one of 1 to 9, wherein the semiconductor layer is an organic semiconductor.

According to the present invention, there is provided a thin film transistor having an insulating layer that can be stacked by a coating method using a non-halogen solvent, a high response speed (driving speed), a large on / off ratio, and excellent transistor characteristics. it can.
In addition, according to the present invention, it is possible to provide a thin film transistor capable of reducing deterioration with time and reducing environmental load.

It is a figure which shows one Embodiment of the thin-film transistor of this invention. It is a figure which shows other embodiment of the thin-film transistor of this invention. It is a figure which shows other embodiment of the thin-film transistor of this invention. It is a figure which shows other embodiment of the thin-film transistor of this invention. It is a figure which shows other embodiment of the thin-film transistor of this invention. It is a figure which shows other embodiment of the thin-film transistor of this invention. It is a figure which shows one Embodiment of the thin-film transistor of this invention which has Si substrate of a board | substrate and gate electrode, and the electrode for lead wire connection.

In the thin film transistor of the present invention, at least three terminals of a gate electrode, a source electrode and a drain electrode, an insulator layer and an organic semiconductor layer are provided on a substrate, and a source-drain current is controlled by applying a voltage to the gate electrode. The insulator layer is a layer laminated by a coating method, and has a solubility in at least one non-halogen solvent selected from tetrahydrofuran, cyclohexanenone and toluene, and is represented by the following formula (I). The polycarbonate which consists of a repeating unit is contained.

(In the formula, Ar is a divalent aromatic group.)

The insulator layer of the thin film transistor of the present invention contains polycarbonate composed of repeating units represented by the formula (I).
The polycarbonate contained in the insulator layer of the thin film transistor of the present invention (hereinafter sometimes simply referred to as the polycarbonate of the present invention) has a solubility in a non-halogen solvent (room temperature and normal pressure) of 5% by weight or more, preferably 7% by weight. Or more, more preferably 10% by weight or more. In addition, although the upper limit of solubility is so preferable that it is high, the upper limit of substantial solubility is 40 weight%.

Since the polycarbonate of the present invention has a solubility in a non-halogen solvent of 5% by weight or more, when laminating the insulator layer of the thin film transistor of the present invention, the polycarbonate of the present invention is dissolved in the non-halogen solvent to form the insulator. The layers can be laminated by a coating method. Since the non-halogen solvent does not contain halogen atoms that cause environmental destruction and device performance deterioration, the thin film transistor of the present invention has a small environmental load during device fabrication and can also reduce deterioration over time.

Examples of the non-halogen solvent include aromatic solvents such as benzene, toluene and xylene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, alcohols such as methanol, ethanol and isopnopanol, esters such as ethyl acetate and ethyl cellosolve, tetrahydrofuran ( THF), ethers such as dioxane, dimethylformamide, dimethyl sulfoxide, diethylformamide and the like.

In the polycarbonate of the present invention, Ar in formula (I) is preferably a linking group represented by the following formula (1) or (2), and among these linking groups, Ar in formula (I) is more preferable. Is a linking group represented by the formula (2), X is a linking group represented by the formula (2a), and R ⁵ and R ⁶ are cycloalkylidene groups having 4 to 12 carbon atoms bonded to each other. It is a certain linking group.

(Wherein R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and at least one of R is an alkyl group having 1 to 3 carbon atoms, and preferably at least 3 are 1 to 3 carbon atoms) The alkyl group of

(The linking group represented by the formula (2c) may be o-, m-, or p-)

(In the formula, two of R ⁷ to R ¹² are bonding groups, and R ⁷ to R ¹² that are bonding groups are each a single bond or an alkylene group, and each of R ⁷ to R ¹² that is not a bonding group is It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

In the polycarbonate of the present invention, Ar in formula (I) is preferably a bonding group represented by the following formula (3), a bonding group represented by the following formula (4), or the following formula (5) having an asymmetric structure. It is the coupling group represented by these.

(Wherein R ¹³ and R ¹⁴ are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom.
R ¹⁵ and R ¹⁶ are different from each other, and each is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. )

(In the formula, X is the same as the formula (2).
R ¹⁷ and R ¹⁸ are each an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. )

(Wherein R ¹⁹ is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and R ²⁰ is an aryl group having 6 to 12 carbon atoms, respectively. And an aliphatic hydrocarbon group having 4 to 12 carbon atoms.)

In the polycarbonate of the present invention, Ar in formula (I) preferably has a linking group represented by the following formulas (6a), (6b) and (6c), and the number of these linking groups is (6a + 6c) / (6a + 6b + 6c) = 0.05 to 0.95 is satisfied.

(In the formula, X is the same as the formula (2).
Each R is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. )

In the above formula (6a + 6c) / (6a + 6b + 6c), 6a is the number of bonding groups represented by formula (6a), 6b is the number of bonding groups represented by formula (6b), and 6c is formula (6c). ) Is the number of linking groups represented.

The above (6a + 6c) / (6a + 6b + 6c) is more preferably 0.1 to 0.7, and further preferably 0.2 to 0.5.
When (6a + 6c) / (6a + 6b + 6c) is less than 0.05, the polycarbonate may be insoluble in the non-halogen solvent.

As the polycarbonate of the present invention, instead of the polycarbonate composed of the repeating unit represented by the above formula (I), a repeating unit represented by the following formula (II) and a repeating unit represented by the following formula (III) Polycarbonate made of a polymer can be used.

(Wherein R ³ and R ⁴ are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom.
X represents —O—, —S—, —SO—, —SO ₂ —, —CO—, 9,9-fluorenylidene group, the above formula (2a), (2b), (2c), or (2d) It is a linking group represented. )

In a polycarbonate composed of a copolymer of the repeating unit represented by the above formula (II) and the repeating unit represented by the above formula (III), it is represented by the repeating unit represented by the formula (II) and the formula (III). The ratio of repeating units is preferably (II) / ((II) + (III)) = 0.05 to 0.95.
When (II) / ((II) + (III)) is less than 0.05 or more than 0.95, for example, when the polycarbonate has a highly crystalline skeleton such as bisphenol A, the characteristics are strongly expressed. The solubility in non-halogen solvents may be reduced.

The polycarbonate composed of a copolymer of the repeating unit represented by the formula (II) and the repeating unit represented by the formula (III) is similar to the polycarbonate composed of the repeating unit represented by the formula (I). The solubility in at least one non-halogen solvent selected from tetrahydrofuran, cyclohexanone and toluene is 5% by weight or more. Therefore, a polycarbonate composed of a copolymer of the repeating unit represented by the above formula (II) and the repeating unit represented by the above formula (III) is dissolved in a non-halogen solvent, and the solution is used for coating. The insulator layer of the thin film transistor of the present invention can be stacked.

A polycarbonate comprising a repeating unit represented by the formula (I), and a polycarbonate comprising a repeating unit represented by the formula (II) and a copolymer of the repeating unit represented by the formula (III) are chlorinated at 20 ° C. The reduced viscosity [η _SP / C] of a solution having a concentration of 0.5 g / dl using methylene as a solvent is preferably 0.1 to 5 dl / g, more preferably 0.3 to 3 dl / g, and particularly preferably 0.5 to 2.5 dl / g.
When the reduced viscosity [η _SP / C] is less than 0.1 g / dl, the strength of the coating film is insufficient, and problems such as peeling and cracking may occur. On the other hand, when the reduced viscosity [η _SP / C] exceeds 5 dl / g, when the film is formed from the coating solution, the coating viscosity becomes too high, resulting in a decrease in productivity and unevenness in the film thickness. May occur.

The reduced viscosity of the polycarbonate can be controlled within the above range by, for example, selecting reaction conditions and adjusting the amounts of branching agent and molecular weight regulator used. Further, the obtained polycarbonate is appropriately subjected to physical treatment (mixing, fractionation, etc.) and / or chemical treatment (polymer reaction, crosslinking treatment, partial decomposition treatment, etc.) to obtain a predetermined reduced viscosity [η _SP / c ] Polycarbonate.

The alkyl group having 1 to 3 carbon atoms of R ¹ , R ² and R in the formula (2b) is preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group.
As the alkyl group having 1 to 4 carbon atoms of R ⁷ to R ¹² , a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 2-butyl group, a t-butyl group, and an isobutyl group are preferable. .
The alkylene group for R ⁷ to R ¹² is preferably a 1,7-heptylene group, a 1,8-octylene group, a 1,10-decylene group or a 1,12-dodecylene group.
Examples of R ³ to R ⁶ , R ¹³ to R ¹⁹ , and R 1 to C 6 aliphatic hydrocarbon groups of formulas (6a), (6b), and (6c) include a methyl group, an ethyl group, n- Propyl group, isopropyl group, n-butyl group, 2-butyl group, t-butyl group, isobutyl group, pentyl group and hexyl group are preferred. R ³ to R ⁶ , R ¹³ to R ²⁰ , and formulas (6a), ( The aryl group having 6 to 12 carbon atoms of R in 6b) and (6c) is preferably a phenyl group, a naphthyl group, or a biphenyl group.
Examples of the cycloalkylidene group having 4 to 12 carbon atoms of R ⁵ and R ⁶ include 1,1-cyclopentylidene group, 1,1-cyclohexylidene group, 1,1-cyclooctylidene group, 1,1-cyclohexane. A dodecylidene group is preferred.
The aliphatic hydrocarbon group having 4 to 12 carbon atoms of R ²⁰ is preferably a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, or a dodecyl group.

The polycarbonate of the present invention may be composed only of the above repeating units, and if the solubility in a non-halogen solvent is 5 wt% or more, other repeating units other than those described above may be used within a range not hindering the object of the present invention. You may have.

Further, the insulator layer of the thin film transistor of the present invention may be composed only of the polycarbonate of the present invention, or other polycarbonate component, polyimide, polyamide, polyester, polyacrylate, photo radical polymerization system, photo cation polymerization system. Photo-curing resin, copolymer containing acrylonitrile component, polyvinylphenol, polyvinyl alcohol, novolac resin, and cyanoethyl pullulan, wax, polyethylene, polychloropyrene, polyethylene terephthalate, polyoxymethylene, polyvinyl chloride, polyvinylidene fluoride, polymethyl Methacrylate, polysulfone, polycarbonate, polyimide cyanoethyl pullulan, poly (vinylphenol) (PVP), poly (methyl methacrylate) (PMMA), police Ren (PS), polyolefins, polyacrylamide, poly (acrylic acid), novolak resins, resol resins, polyimides, polyxylylene, in addition to the epoxy resin, polymers of pullulan, and additives may be included as appropriate further.

The polycarbonate of the present invention can be produced by reacting a dihydric phenol and a carbonate ester-forming compound. For example, dihydric phenol (IV) and / or dihydric phenol (IV) represented by the following formula (IV): Can be produced by reacting a dihydric phenol having another structure with a carbonate-forming compound.

(In the formula, R ³ , R ⁴ and X are the same as in formula (2).)

Specific examples of the dihydric phenol represented by the formula (IV) include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 1,2-bis (4-hydroxyphenyl). Ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, 4,4-bis (4-hydroxyphenyl) heptane, 3,3-bis (4-hydroxyphenyl) pentane, 4,4′-dihydroxytetraphenylmethane, 1,1-bis ( 4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylmethane, bis (4-hydroxyphenyl) ) Ether, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2, 2-bis (3-methyl-4-hydroxyphenyl) propane, 2- (3-methyl-4-hydroxyphenyl) -2- (4-hydroxyphenyl) -1-phenylethane, bis (3-methyl-4- Hydroxyphenyl) sulfide, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) methane, 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 2, 2-bis (2-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,6-dimethyl) 4-hydroxyphenyl) propane, 2,2-bis (3-cyclohexyl-4-hydroxyphenyl) propane, 1,1-bis (2-butyl-4-hydroxy-5-methylphenyl) butane, 1,1 -Bis (2-tert-butyl-4-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-tert-butyl-4-hydroxy-5-methylphenyl) propane, 1,1-bis (2 -Tert-butyl-4-hydroxy-5-methylphenyl) butane, 1,1-bis (2-tert-butyl-4-hydroxy-5-methylphenyl) isobutane, 1,1-bis (2-tert-butyl) -4-hydroxy-5-methylphenyl) heptane, 1,1-bis (2-tert-butyl-4-hydroxy-5-methylphenyl) -1-fur Nylmethane, 1,1-bis (2-tert-amyl-4-hydroxy-5-methylphenyl) butane, bis (3-chloro-4-hydroxyphenyl) methane, bis (3,5-dibromo-4-hydroxyphenyl) ) Methane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 2,2-bis (3-fluoro-4-hydroxyphenyl) propane, 2,2-bis (3-bromo-4-hydroxy) Phenyl) propane, 2,2-bis (3,5-difluoro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (3 5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3-bromo-4-hydroxy-5-chlorophenyl) propane, 2,2-bis ( 3,5-dichloro-4-hydroxyphenyl) butane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) butane, 1-phenyl-1,1-bis (3-fluoro-4-hydroxyphenyl) ) Ethane, bis (3-fluoro-4-hydroxyphenyl) ether, 1,1-bis (3-cyclohexyl-4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxy-3, 3'-dimethylbiphenyl, 4,4'-dihydroxy-2,2'-dimethylbiphenyl, 4,4'-dihydroxy-3,3'-dicyclohexylbiphenyl, 3,3'-difluoro-4,4'-dihydroxybiphenyl 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-phenyl- -Hydroxyphenyl) propane, 1,1-bis (3-phenyl-4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, bis (3-phenyl-4-hydroxyphenyl) sulfone, bis (4-hydroxy Phenyl) ether, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, 1,1-bis (4-hydroxyphenyl) -3,3 5-trimethylcyclohexane, 4,4 ′-[1,4-phenylenebis (1-methylethylidene)] bisphenol, 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol, 1,1 -Bis (3-methyl-4-hydroxyphenyl) cyclopentane and the like.

The dihydric phenol represented by the formula (IV) is preferably substituted at the ortho position of each divalent phenol having an asymmetric structure represented by the following formula (V), or each benzene ring represented by the following formula (VI) A dihydric phenol having a group, a dihydric phenol in which R ⁵ and R ⁶ represented by the following formula (VII) are bonded to each other to form a cycloalkylidene group having 4 to 12 carbon atoms, represented by the following formula (VIII): Or a dihydric phenol in which (6a + 6c) / (6a + 6b + 6c) represented by the following formula (IX) satisfies 0.05 to 0.95.

(In the formula, R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are the same as in formula (3).)

(In the formula, X, R ¹⁷ and R ¹⁸ are the same as in formula (4).)

(In formula, R < ³ >, R < ⁴ > is the same as that of Formula (2).
R ⁵ and R ⁶ are cycloalkylidene groups having 4 to 12 carbon atoms bonded to each other. )

(In the formula, R ¹⁹ and R ²⁰ are the same as in formula (5).)

Specific examples of the dihydric phenol represented by the formula (V) and the dihydric phenol represented by the formula (VI) include 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2 -Bis (3-methyl-4-hydroxyphenyl) propane and 2,2-bis (3-phenyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, 2, 2-bis (4-hydroxy-3-cyclohexylphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,6-dimethylphenyl) ) Propane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (3-methyl-4-hydride) Kishifeniru) cyclopentane, 9,9-bis (3-methyl-4-hydroxyphenyl) include fluorene.

In the production of the polycarbonate of the present invention, carbonylforms such as phosgene, haloformates such as chloroformate compounds, or carbonate ester compounds are used as carbonate ester-forming compounds in the presence of an appropriate acid binder. The polycondensation reaction can be performed.
The polycondensation reaction in the presence of an acid binder using carbonyl halide, haloformate, carbonate ester compound or the like as the carbonate ester-forming compound is usually performed in a solvent or without solvent.

Phosgene is mentioned as a dihalogenated carbonyl which is a carbonic acid ester forming compound.
Examples of haloformates that are carbonate-forming compounds include chloroformate.
Examples of the carbonate compound include dimethyl carbonate and diphenyl carbonate.

The proportion of carbonate ester-forming compound used may be adjusted as appropriate in consideration of the stoichiometric ratio (equivalent) of the reaction. Moreover, when the carbonic acid ester forming compound is gaseous such as phosgene, a method of blowing the gas into the reaction system can be suitably employed.

As the acid binder, for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, organic bases such as pyridine, or a mixture thereof can be used. .

The ratio of the acid binder to be used may be appropriately determined in consideration of the stoichiometric ratio (equivalent) of the reaction, and is preferably based on the number of moles of the dihydric phenol to be used (usually 1 mole corresponds to 2 equivalents). 2 equivalents or more than 2 equivalents.

As the solvent, a known solvent that can be used for the production of polycarbonate may be used alone or as a mixed solvent. Specific examples of the solvent include hydrocarbon solvents such as toluene and xylene, methylene chloride, chlorobenzene and the like. And halogenated hydrocarbon solvents.
The interfacial polycondensation reaction may be carried out using two kinds of solvents that do not mix with each other as the solvent. It is desirable to do.

In order to accelerate the polycondensation reaction, it is desirable to add a catalyst such as a tertiary amine such as triethylamine or a quaternary ammonium salt. If desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfide may be added.

The polycondensation reaction is usually performed at a temperature in the range of 0 to 150 ° C., preferably 5 to 40 ° C. The reaction pressure can be any of reduced pressure, normal pressure, and increased pressure. Usually, it can be suitably performed at normal pressure or about the pressure of the reaction system. The reaction time depends on the reaction temperature and the like, but is usually 0.5 minutes to 10 hours, preferably about 1 minute to 2 hours.

The polycondensation reaction is performed in the presence of a terminal terminator and / or a branching agent as necessary.

As the above terminator, monovalent carboxylic acid and derivatives thereof, and monovalent phenol can be used, for example, p-tert-butyl-phenol, p-phenylphenol, p-cumylphenol, p-perfluorophenol. Fluorononylphenol, p-perfluorooctylphenol, p-perfluorohexylphenol, p- (perfluorononylphenyl) phenol, p- (perfluorooxylphenyl) phenol, p-tert-perfluorobutylphenol, 1- (P-hydroxy) Benzyl) perfluorodecane, p- [2- (1H, 1H-perfluorotridodecyloxy) -1,1,1,3,3,3-hexafluoropropyl] phenol, 3,5-bis (perfluorohexyl) Oxycarbonyl) phenol, p-hy Perfluorododecyl loxybenzoate, p- (1H, 1H-perfluorooctyloxy) phenol, 2H, 2H, 9H-perfluorononanoic acid, 1,1,1,3,3,3-tetrafluoro-2-propanol, Alternatively, alcohol represented by the following formula is preferably used.
H (CF ₂ ) _n CH ₂ OH
(Where n is an integer from 1 to 12)
F (CF ₂ ) _m CH ₂ OH
(Where m is an integer from 1 to 12)

The addition ratio of the end terminator is preferably from 0.05 to 30 mol%, more preferably from 0.0 to 30 mol% in terms of copolymer composition ratio (number of moles of end terminator / (number of moles of polycarbonate main chain monomer unit + number of terminal moles)). If the addition ratio is more than 30 mol%, the mechanical strength may be lowered, and if it is less than 0.05 mol%, the viscosity of the coating solution becomes too high. There is a possibility that unevenness in thickness occurs or moldability is lowered.

Examples of branching agents include phloroglysin, pyrogallol, 4,6-dimethyl-2,4,6-tris (4-hydroxyphenyl) -2-heptene, 2,6-dimethyl-2,4,6-tris (4- Hydroxyphenyl) -3-heptene, 2,4-dimethyl-2,4,6-tris (4-hydroxyphenyl) heptane, 1,3,5-tris (2-hydroxyphenyl) benzene, 1,3,5- Tris (4-hydroxyphenyl) benzene, 1,1,1-tris (4-hydroxyphenyl) ethane, tris (4-hydroxyphenyl) phenylmethane, 2,2-bis [4,4-bis (4-hydroxyphenyl) ) Cyclohexyl] propane, 2,4-bis [2-bis (4-hydroxyphenyl) -2-propyl] phenol, 2,6-bis (2-hydroxy) 5-methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) propane, tetrakis (4-hydroxyphenyl) methane, tetrakis [4- (4-hydroxyphenyl) Isopropyl) phenoxy] methane, 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric acid, 3,3-bis (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole, 3,3 -Bis (4-hydroxyaryl) oxindole, 5-chloroisatin, 5,7-dichloroisatin, 5-bromoisatin and the like.

The addition ratio of the branching agent is 30 mol% or less, preferably 5 mol% or less in the copolymer composition ratio (number of moles of branching agent / (number of moles of polycarbonate main chain monomer units + number of moles of branching agent)). When the ratio exceeds 30 mol%, the viscosity of the coating solution becomes too high, and thus there is a possibility that the film thickness may be uneven or the moldability may be lowered.

The production of the polycarbonate of the present invention can also be carried out by a transesterification reaction using bisaryl carbonates as the carbonate forming compound.

Examples of bisaryl carbonates that are carbonate ester forming compounds include diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate, and the like.

As the reaction mode of the transesterification reaction, a melt polycondensation method, a solid phase polycondensation method, or the like is preferable.
When performing the melt polycondensation method, the reaction can be performed in a molten state at a high temperature under reduced pressure. The reaction is usually carried out at a temperature in the range of 150 to 350 ° C, preferably 200 to 300 ° C. On the other hand, when the solid phase polycondensation method is performed, the reaction (polycondensation) can be performed by heating to a temperature not higher than the melting point of the produced polycarbonate in the solid phase state.

In both the melt polycondensation method and the solid phase polycondensation method, the degree of vacuum is preferably 1 mmHg or less in the final stage of the reaction, and phenols derived from the bisaryl carbonates produced by the transesterification reaction are excluded from the system. To distill off. The reaction time depends on the reaction temperature, the degree of reduced pressure, etc., but is usually about 1 to 4 hours. The reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon, and the reaction may be performed by adding an antioxidant or the like as desired.
The obtained reaction product (crude product) can be recovered as polycarbonate having a desired purity (purity) by performing various post-treatments such as a known separation and purification method.

The thin film transistor of the present invention can take several structures depending on the position of electrodes, the stacking order of layers, and the like, and has a field effect transistor (FET) structure.

FIG. 1 is a diagram showing an embodiment of a thin film transistor of the present invention.
In the thin film transistor 1, the gate electrode 20 is stacked on the substrate 10, and the insulator layer 30 is stacked on the substrate 10 so as to cover the gate electrode 20. On the insulator layer 30, the source electrode 40 and the drain electrode 50 are stacked in parallel with a predetermined gap therebetween. The semiconductor layer 60 is stacked on the insulator layer 30, the source electrode 40, and the drain electrode 50 so as to fill a gap between the source electrode 40 and the drain electrode 50.
The semiconductor layer 60 forms a channel region, and is turned on / off by controlling a current flowing between the source electrode 40 and the drain electrode 50 with a voltage applied to the gate electrode 20.

FIG. 2 is a diagram showing another embodiment of the thin film transistor of the present invention.
The thin film transistor 2 includes a semiconductor layer 60 stacked on the insulator layer 30 and a source electrode 40 and a drain electrode 50 stacked on the semiconductor layer 60 in parallel with a predetermined interval therebetween. It has the same structure as the thin film transistor 1.

FIG. 3 is a diagram showing another embodiment of the thin film transistor of the present invention.
In the thin film transistor 3, the source electrode 40 and the drain electrode 50 are stacked in parallel on the substrate 10 at a predetermined interval, and the semiconductor layer 60 fills the gap between the source electrode 40 and the drain electrode 50. The substrate 10 is stacked on the source electrode 40 and the drain electrode 50. An insulator layer 30 is stacked on the semiconductor layer 60, and the gate electrode 20 is stacked on the insulator layer 30.

FIG. 4 is a diagram showing another embodiment of the thin film transistor of the present invention.
In the thin film transistor 4, a semiconductor layer 60 is stacked on the substrate 10, and a source electrode 40 and a drain electrode 50 are stacked in parallel on the semiconductor layer 60 at a predetermined interval. The insulator layer 30 is stacked on the source electrode 40, the drain electrode 50, and the semiconductor layer 60 so as to fill a gap between the source electrode 40 and the drain electrode 50, and the gate electrode 20 is formed on the insulator layer 30. Laminated.
In the case where an inorganic semiconductor is used as a material for the semiconductor layer, an element structure called a top gate type shown in FIGS. 3 and 4 is preferable in order not to damage the polycarbonate layer which is an insulator layer.

The thin film transistor of the present invention includes an organic semiconductor layer (organic compound layer) or an inorganic semiconductor layer, a source electrode and a drain electrode formed so as to face each other with a predetermined interval, and a source electrode and a drain electrode, respectively. And a gate electrode formed at a distance of λ, and a current flowing between the source and drain electrodes is controlled by applying a voltage to the gate electrode.

The thin film transistor of the present invention only needs to have a mechanism in which effects such as on / off operation and amplification are manifested by controlling the current flowing between the source electrode and the drain electrode by the voltage applied to the gate electrode. The device configuration is not limited to the above.
The thin film transistor of the present invention is, for example, a top-and-bottom contact type organic material proposed by Yoshida et al. Of the National Institute of Advanced Industrial Science and Technology in the 49th Conference on Applied Physics Related Lectures 27a-M-3 (March 2002). It may have a device configuration such as a thin film transistor (see FIG. 5) and a vertical organic thin film transistor (see FIG. 6) proposed by Kudo et al. Of Chiba University in the IEEJ Transaction 118-A (1998), page 1440. .

Hereinafter, each component of the thin film transistor of the present invention will be described.
The insulator layer of the thin film transistor of the present invention is a layer laminated by a coating method, and is a layer containing the polycarbonate of the present invention.
Polycarbonate generally has a low dielectric constant, so it is better to be as thin as possible in order to lower the driving voltage of the thin film transistor. On the contrary, since the leakage current between the source and gate increases as the film thickness decreases, select an appropriate film thickness. There is a need. The thickness of the insulator layer is usually 10 nm to 5 μm, preferably 50 nm to 2 μm, more preferably 100 nm to 1 μm.

The insulator layer is obtained by applying a solution obtained by dissolving the polycarbonate of the present invention in a non-halogen solvent by a coating method such as a dipping method, a spin coating method, a casting method, a bar coating method, or a roll coating method, and baking the coating layer. They can be laminated by electropolymerization, self-assembly from solution, or a combination thereof.

The insulator layer may be only a layer containing the polycarbonate of the present invention, or may be a laminate of two or more layers including an insulator layer made of another material. Even if the insulator layer is only a layer containing the polycarbonate of the present invention, since it has high insulation, a high-performance organic thin film transistor can be produced by making it sufficiently thin, but other insulators having a high dielectric constant By combining with a layer, the threshold voltage can be reduced more easily.

Generally, a polymer having a small surface energy has a low relative dielectric constant and a high threshold voltage of a thin film transistor. JP-A-2005-72569 and JP-A-2005-013468 disclose an organic thin film transistor having a high mobility and a low threshold voltage by combining an insulating layer having a high relative dielectric constant and a liquid phase low dielectric constant polymer. ing. In the present invention, in the case of using a laminate of two or more insulator layers, if the first insulator layer in direct contact with the semiconductor includes the polycarbonate of the present invention, the material and formation of the second insulator layer in contact with the gate electrode The method is not particularly limited.

The first insulator layer is a layer containing the polycarbonate of the present invention and laminated by a coating method. The thinner the continuous film, the better. For example, the thickness is 0.5 nm to 100 nm, preferably 1 nm to 20 nm, and more preferably 1 nm to 10 nm.

The material forming the second insulator layer is a room temperature (for example, 20 to 25 ° C.) such as a metal oxide (including silicon oxide), a metal nitride (including silicon nitride), a polymer, or a small organic molecule. ) In which the electrical resistivity is 10 Ωcm or more, and a material having a relative dielectric constant higher than 3 is particularly preferable.
By forming the second insulator layer from the above material, an accumulation layer is easily generated in the semiconductor layer, and the threshold voltage for transistor operation can be reduced.

Examples of the metal oxide and metal nitride forming the second insulator layer include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, zirconium. Lead titanate, lanthanum titanate, strontium titanate, barium titanate, barium magnesium fluoride, lanthanum oxide, fluorine oxide, magnesium oxide, bismuth oxide, bismuth titanate, niobium oxide, strontium titanate Examples thereof include bismuth, strontium bismuth tantalate, tantalum pentoxide, bismuth tantalate niobate, trioxide yttrium, and combinations thereof. Silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable.
In addition, inorganic nitrides such as silicon nitride (Si ₃ N ₄ , SixNy, SiONx (x, y> 0)) and aluminum nitride can also be suitably used. By forming the insulator layer from silicon nitride such as Si ₃ N ₄ , SixNy, or SiONx (x, y> 0), a storage layer is more easily generated, and the threshold voltage for transistor operation can be further reduced. .

The second insulator layer may be formed of a precursor containing an alkoxide metal.
The metal of the alkoxide metal is selected from, for example, a transition metal, a lanthanoid, or a main group element. Specifically, barium (Ba), strontium (Sr), titanium (Ti), bismuth (Bi), tantalum ( Ta), zircon (Zr), iron (Fe), nickel (Ni), manganese (Mn), lead (Pb), lanthanum (La), lithium (Li), sodium (Na), potassium (K), rubidium ( Rb), cesium (Cs), francium (Fr) beryllium (Be) magnesium (Mg), calcium (Ca), niobium (Nb), thallium (Tl), mercury (Hg), copper (Cu), cobalt (Co) , Rhodium (Rh), scandium (Sc), yttrium (Y), and the like.

Examples of the alkoxide of the alkoxide metal include alcohols including methanol, ethanol, propanol, isopropanol, butanol, isobutanol, methoxyethanol, ethoxyethanol, propoxyethanol, butoxyethanol, pentoxyethanol, heptoxyethanol, methoxypropanol And alkoxides derived from alkoxy alcohols including ethoxypropanol, propoxypropanol, butoxypropanol, pentoxypropanol, heptoxypropanol, and the like.

The second insulator layer may be formed of an organic compound.
Examples of the organic compound include polyimide, polyamide, polyester, polyacrylate, photo radical polymerization system, photo cation polymerization system photo-curing resin, copolymer containing acrylonitrile component, polyvinyl phenol, polyvinyl alcohol, novolac resin, and Cyanoethyl pullulan or the like can be used.

In addition to the above organic compounds, wax, polyethylene, polychloropyrene, polyethylene terephthalate, polyoxymethylene, polyvinyl chloride, polyvinylidene fluoride, polymethyl methacrylate, polysulfone, polyimide cyanoethyl pullulan, poly (vinylphenol) (PVP), poly (methyl meta Polymer having a high dielectric constant such as crate) (PMMA), polycarbonate (PC), polystyrene (PS), polyolefin, polyacrylamide, poly (acrylic acid), novolac resin, resole resin, polyimide, polyxylylene, epoxy resin, pullulan, etc. Materials can also be used.

The second insulator layer may be a mixed layer using a plurality of the above-described inorganic compound materials or organic compound materials, or may be a laminate of layers made of these materials alone. The second insulator layer may be a mixed layer of a material having a high dielectric constant and a material having water repellency, or a laminate of layers made of these materials alone, if necessary.

The second insulator layer may be an anodized film or may further include the anodized film as a component. In this case, the second insulator layer and the anodic oxide film may be stacked.
The anodized film is formed by anodizing a metal that can be anodized by a known method, and is preferably further sealed.

Examples of the metal that can be anodized include aluminum and tantalum.
There is no restriction | limiting in particular in the method of an anodizing process, A well-known method can be used. An oxide film is formed by anodizing. The electrolytic solution used for the anodizing treatment is not particularly limited as long as it is an electrolytic solution capable of forming a porous oxide film. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, boric acid, sulfamic acid, benzene A sulfonic acid or the like, or a mixed acid obtained by combining two or more of these or a salt thereof is used.

The treatment conditions for anodization differ depending on the electrolyte used, but in general, the concentration of the electrolyte is 1 to 80% by mass, the temperature of the electrolyte is 5 to 70 ° C., and the current density is 0.5 to 60 A / cm ^2. A voltage of 1 to 100 volts and an electrolysis time of 10 seconds to 5 minutes are suitable. A preferred anodizing treatment is a method in which an aqueous solution of sulfuric acid, phosphoric acid or boric acid is used as the electrolytic solution, and the treatment is performed with a direct current, and an alternating current can also be used. The concentration of the acid in the electrolytic solution is preferably 5 to 45% by mass, and the electrolytic treatment is preferably performed at a temperature of the electrolytic solution of 20 to 50 ° C. and a current density of 0.5 to 20 A / cm ² for 20 to 250 seconds.

If the thickness of the second insulator layer is small, the effective voltage applied to the organic semiconductor increases, so that the drive voltage and threshold voltage of the device itself can be lowered. Therefore, it is necessary to select an appropriate film thickness. The thickness of the second insulator layer is usually 10 nm to 5 μm, preferably 50 nm to 2 μm, more preferably 100 nm to 1 μm.

The method for forming the second insulator layer is not particularly limited and can be used for vapor phase deposition or liquid phase deposition. For example, vacuum deposition, molecular beam epitaxy, ion cluster beam method, low energy ion beam method, ion plate Atmospheric pressure described in JP-A-11-61406, JP-A-11-133205, JP-A-2000-121804, JP-A-2000-147209, and JP-A-2000-185362 Gas phase film formation such as plasma method; and liquid phase film formation such as spray coating method, spin coating method, blade coating method, dip coating method, casting method, roll coating method, bar coating method, die coating method, printing and inkjet. Can be used depending on the material.

In the lamination of the second insulator layer, the wet process applies and dries a liquid in which fine particles of inorganic oxide are dispersed in an arbitrary organic solvent or water using a dispersion aid such as a surfactant as necessary. A so-called sol-gel method in which a method or a solution of an oxide precursor, for example, an alkoxide body is applied and dried can be used. For example, when the second insulator layer is formed of a precursor containing an alkoxide metal, the insulator layer can be formed by coating the substrate with a solution of the precursor and subjecting the coating layer to chemical solution treatment including heat treatment. .

The substrate plays a role in supporting the structure of the thin film transistor. As a material, in addition to glass, inorganic compounds such as metal oxides and nitrides, plastic films (PET, PES, PC), metal substrates, or composites thereof It is also possible to use a laminate or the like. In the case where the structure of the thin film transistor can be sufficiently supported by components other than the substrate, the substrate can be omitted.
Further, a silicon (Si) wafer is often used as a material for the substrate. In this case, Si itself can be used as a gate electrode / substrate. Further, the surface of Si can be oxidized to form SiO ₂ and used as an insulating layer. In this case, as shown in FIG. 7, a metal layer such as Au may be formed as an electrode 70 for connecting a lead wire on the Si substrate 12 serving as a substrate and gate electrode. In FIG. 7, 12 is a heavily doped Si substrate (gate electrode), 32 is a SiO ₂ layer (insulating layer), 42 is an Au electrode (source electrode), 52 is an Au electrode (drain electrode), and 60 is a semiconductor layer. , 70 is a lead wire connecting electrode, 72 is an Au metal layer, and 74 is a Cr metal layer.
In the thin film transistor of FIG. 7, the polycarbonate of the present invention is used for the first insulator layer disposed between the SiO ₂ layer (insulating layer) and the semiconductor layer.

The semiconductor used for the semiconductor layer is not particularly limited as to whether it is organic or inorganic. For example, when an organic semiconductor layer is formed using an organic semiconductor, the organic semiconductor described in Chemical Review, Vol. 107, page 1066, 2007 Materials and the like can be used.
The organic semiconductor layer may be a layer made of a mixture of a plurality of materials by combining a plurality of materials selected from the above organic semiconductor materials, or a laminate of layers made of these materials alone.

Specific examples of the material of the organic semiconductor layer include low molecular materials such as pentacene, naphthacene, anthracene, heptacene, hexacene, C60, C70, phenanthrene, pyrene, chrysene, perylene, coronene, rubrene, phthalocyanines, porphyrins, and derivatives thereof. Oligomers such as distyrylbenzene, oligoacetylene, oligothiophene, oligoselenophene and derivatives thereof; polyacetylene, polythiophene, poly (3-hexylthiophene), poly (9,9-dioctylfluorene-co-bithiphene), polyphenylene vinylene And π-conjugated polymers such as polythienylene vinylene and derivatives thereof, but are not limited thereto.

Examples of using an inorganic semiconductor as the semiconductor layer include non-single-crystal semiconductor films such as amorphous silicon, polycrystalline silicon, and microcrystalline silicon, crystalline silicon, ZnO, a- Examples include compound semiconductors such as InGaZnO, SiGe, and GaAs, or oxide semiconductors, but are not limited thereto.

The thickness of the semiconductor layer is not particularly limited, but is usually 0.5 nm to 1 μm, preferably 2 nm to 250 nm.

A method for forming the semiconductor layer is not particularly limited, and a known method can be applied.
For example, in the case of an element structure such as the organic thin film transistors 1 and 2 of FIGS. 1 and 2, the organic semiconductor layer is preferably formed without exposure to the atmosphere after the polycarbonate insulator layer is formed. The film formation is preferably vapor phase film formation such as molecular beam vapor deposition (MBE), vacuum vapor deposition, chemical vapor deposition, molecular beam vapor deposition, or sputtering. In addition to the film formation method, a coating layer is formed by a printing / coating method such as a dipping method, a spin coating method, a casting method, a bar coating method, or a roll coating method in which a material is dissolved in a solvent, and the coating layer is baked. It is also desirable to form the film by means of electropolymerization, self-assembly from solution, and a combination thereof.
The organic semiconductor layer formation may be a combination of two or more of the above film formation methods.

Further, in the case of an element configuration such as the organic thin film transistors 3 and 4 in FIGS. 3 and 4, it is desirable to form a polycarbonate layer (insulator layer) without exposing the organic semiconductor layer to the air after forming the organic semiconductor layer. In this case, the stacking of the organic semiconductor layers is not particularly limited, and the above film formation method can be applied, but vapor phase film formation is preferable.

The method for forming a semiconductor layer of the present invention may be a known method, and desirably, the steps of forming a semiconductor and an insulating film layer are preferably performed continuously without being exposed to the atmosphere as described above. However, when a p-type organic semiconductor material is selected as the semiconductor layer, it is desirable to expose the semiconductor material whose performance is improved by exposure to the air in the steps after the semiconductor-insulator layer forming step.

Since the field effect mobility can be improved by improving the crystallinity of the semiconductor layer, when vapor phase film formation (evaporation, sputtering, etc.) is used for film formation of the organic semiconductor layer, It is desirable to maintain the substrate temperature at a high temperature. The temperature is preferably 50 to 250 ° C., more preferably 70 to 150 ° C. In addition, it is preferable to perform annealing after film formation regardless of the film forming method because a high-performance device can be obtained. The annealing temperature is preferably 50 to 200 ° C., more preferably 70 to 200 ° C., and the time is preferably 10 minutes to 12 hours, more preferably 1 to 10 hours.

The material of the gate electrode, the source electrode, and the drain electrode is not particularly limited as long as it is a conductive material. Platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony, 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-potassium alloy, aluminum, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum Um mixture, a magnesium / indium mixture, aluminum / aluminum oxide mixture, can be used lithium / aluminum mixtures.

The thicknesses of the gate electrode, the source electrode, and the drain electrode are not particularly limited as long as current is conducted, but is preferably in the range of 0.2 nm to 10 μm, more preferably 4 nm to 300 nm. If the film thickness of the electrode is within the above range, the resistance is not increased due to the thin film thickness, voltage drop does not occur, and the film formation does not take time because it is not too thick. When other layers such as the above are laminated, a laminated film can be made smoothly without causing a step.
The source electrode and the drain electrode are stacked with a predetermined interval, for example. The interval is determined by the use of the thin film transistor, and is usually 0.1 μm to 1 mm, preferably 1 μm to 100 μm, more preferably 5 μm to 100 μm.

The source electrode and the drain electrode are made of a fluid electrode material such as a solution, paste, ink, dispersion, etc., preferably a conductive polymer, or metal fine particles containing platinum, gold, silver, or copper. It can be formed using a fluid electrode material containing.

The solvent or dispersion medium of the fluid electrode material is preferably a solvent or dispersion medium containing 60 mass% or more, preferably 90 mass% or more of water in order to suppress damage to the organic semiconductor.
As the dispersion containing metal fine particles, for example, a known conductive paste or the like may be used. However, the dispersion usually contains metal fine particles having a particle diameter of 0.5 nm to 50 nm, preferably 1 nm to 10 nm. And preferred. Examples of the fine metal particles include platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, and zinc. Can be used.

It is preferable to form an electrode using a dispersion in which these metal fine particles are dispersed in water or a dispersion medium which is an arbitrary organic solvent using a dispersion stabilizer mainly composed of an organic material.
The metal fine particle dispersion may be produced by reducing metal ions in a liquid phase such as a gas phase evaporation method, a sputtering method, a metal vapor synthesis method, or a liquid phase such as a colloid method or a coprecipitation method. The colloidal method described in JP-A-11-76800, JP-A-11-80647, JP-A-11-319538, JP-A-2000-239853, and the like is preferable. Metal fine particles produced by a gas evaporation method described in JP-A Nos. 2001-254185, 2001-53028, 2001-35255, 2000-124157, 2000-123634, etc. Is a dispersion of

Specifically, the electrode is formed using the metal fine particle dispersion after the solvent of the metal fine particle dispersion is dried and then shaped in the range of 100 ° C. to 300 ° C., preferably 150 ° C. to 200 ° C. as necessary. By heating in this manner, the metal fine particles are thermally fused to form an electrode pattern having a desired shape.

In particular, the material for forming the source electrode and the drain electrode is preferably a material having low electrical resistance at the contact surface with the semiconductor layer. The electric resistance corresponds to the field effect mobility when the current control device is manufactured, and the resistance needs to be as small as possible in order to obtain a large mobility. This is generally determined by the magnitude relationship between the work function of the electrode material and the energy level of the organic semiconductor layer.

When the work function (W) of the electrode material is a, the ionization potential of the organic semiconductor layer is (Ip) b, and the electron affinity (Af) of the organic semiconductor layer is c, it is preferable that the following relational expression is satisfied. Here, a, b, and c are all positive values based on the vacuum level.
In the case of a p-type organic thin film transistor, ba <1.5 eV (formula (A)) is preferable, and ba <1.0 eV is more preferable. If the above relationship can be maintained in relation to the organic semiconductor layer, a high-performance device can be obtained. In particular, it is preferable that the electrode material has a work function as large as possible, and the work function is 4.0 eV or more. The work function is preferably 4.2 eV or more.

The value of the work function of a metal is, for example, an effective metal having a work function of 4.0 eV or higher as described in Chemistry Handbook Fundamentals II-493 (revised 3 edition, published by The Chemical Society of Japan, Maruzen 1983) From the above list.
High work function metals are mainly Ag (4.26, 4.52, 4.64, 4.74 eV), Al (4.06, 4.24, 4.41 eV), Au (5.1, 5.37). 5.47 eV), Be (4.98 eV), Bi (4.34 eV), Cd (4.08 eV), Co (5.0 eV), Cu (4.65 eV), Fe (4.5, 4.67). 4.81 eV), Ga (4.3 eV), Hg (4.4 eV), Ir (5.42, 5.76 eV), Mn (4.1 eV), Mo (4.53, 4.55, 4.. 95 eV), Nb (4.02, 4.36, 4.87 eV), Ni (5.04, 5.22, 5.35 eV), Os (5.93 eV), Pb (4.25 eV), Pt (5 .64 eV), Pd (5.55 eV), Re (4.72 eV), Ru (4.71 eV), Sb (4 55, 4.7 eV), Sn (4.42 eV), Ta (4.0, 4.15, 4.8 eV), Ti (4.33 eV), V (4.3 eV), W (4.47, 4 .63, 5.25 eV) and Zr (4.05 eV). Among these, noble metals (Ag, Au, Cu, Pt), Ni, Co, Os, Fe, Ga, Ir, Mn, Mo, Pd, Re, Ru, V, and W are preferable.
Other than metals, conductive polymers such as ITO, polyaniline and PEDOT: PSS and carbon are preferred. Even if one or more of these high work function substances are included as the electrode material, there is no particular limitation as long as the work function satisfies the formula (A).

In the case of an n-type organic thin film transistor, it is preferable that ac <1.5 eV (formula (B)), and more preferably ac <1.0 eV. If the above relationship can be maintained in relation to the organic semiconductor layer, a high-performance device can be obtained. In particular, the work function of the electrode material is preferably as small as possible, and the work function is preferably 4.3 eV or less. More preferably, the work function is 3.7 eV or less.

As a specific example of the low work function metal, it has a work function of 4.3 eV or more described in, for example, Chemistry Handbook Basics, pages II-493 (revised 3 edition, published by The Chemical Society of Japan, Maruzen Co., Ltd. 1983). What is necessary is just to select from the said list of effective metals.
As the low work function metal, Ag (4.26 eV), Al (4.06, 4.28 eV), Ba (2.52 eV), Ca (2.9 eV), Ce (2.9 eV), Cs (1. 95 eV), Er (2.97 eV), Eu (2.5 eV), Gd (3.1 eV), Hf (3.9 eV), In (4.09 eV), K (2.28), La (3.5 eV) ), Li (2.93 eV), Mg (3.66 eV), Na (2.36 eV), Nd (3.2 eV), Rb (4.25 eV), Sc (3.5 eV), Sm (2.7 eV) , Ta (4.0, 4.15 eV), Y (3.1 eV), Yb (2.6 eV), Zn (3.63 eV), and the like. Among these, Ba, Ca, Cs, Er, Eu, Gd, Hf, K, La, Li, Mg, Na, Nd, Rb, Y, Yb, and Zn are preferable.

As an electrode material, even if one or more of these low work function substances are included, there is no particular limitation as long as the work function satisfies the formula (B). However, since the low work function metal easily deteriorates when exposed to moisture and oxygen in the atmosphere, it is desirable to coat with a stable metal in the air such as Ag and Au as necessary. The film thickness necessary for the coating is 10 nm or more, and as the film thickness increases, it can be protected from oxygen and water. However, for practical reasons, it is desirable to set it to 1 μm or less for the purpose of increasing productivity.

The source electrode and drain electrode can be formed by, for example, vapor deposition, electron beam vapor deposition, sputtering, atmospheric pressure plasma method, ion plating, chemical vapor deposition, electrodeposition, electroless plating, spin coating, printing or ink jet. it can. Moreover, as a patterning method performed as needed, the conductive thin film formed using said method is formed into an electrode using a well-known photolithographic method or a lift-off method, on metal foils, such as aluminum and copper There is a method in which a resist is formed and etched by thermal transfer, ink jet, or the like.

Further, as described above, the source electrode and the drain electrode may be formed by patterning a solution or dispersion of a conductive polymer, a dispersion containing metal fine particles, or the like directly by an ink jet method. You may form by laser ablation etc. Furthermore, it is also possible to use a method in which a conductive ink or conductive paste containing a conductive polymer or metal fine particles is patterned by a printing method such as relief printing, intaglio printing, planographic printing or screen printing.

In addition to the above electrode materials, it is also preferable to use a known conductive polymer whose conductivity is improved by doping or the like as the electrode material of the gate electrode, the source electrode, and the drain electrode. For example, conductive polyaniline, conductive polypyrrole, conductive polythiophene (polyethylenedioxythiophene and polystyrenesulfonic acid complex and the like), polyethylenedioxythiophene (PEDOT) and polystyrenesulfonic acid complex and the like are also preferably used. These materials can reduce the contact resistance between the semiconductor layer of the source electrode and the drain electrode.

In the thin film transistor of the present invention, for the purpose of improving the injection efficiency, for example, a buffer layer may be provided between the organic semiconductor layer and the source and drain electrodes.
The buffer layer provided in the n-type organic thin film transistor has an alkali metal or alkaline earth metal ion bond such as LiF, Li ₂ O, CsF, NaCO ₃ , KCl, MgF ₂ , and CaCO ₃ used for the cathode of the organic electroluminescence element. Compounds are desirable.
The buffer layer provided in the p-type organic thin film transistor includes cyano compounds such as FeCl ₃ , TCNQ, F ₄ -TCNQ, HAT; CFx, GeO ₂ , SiO ₂ , MoO ₃ , V ₂ O ₅ , VO ₂ , V ₂ O ₃ , Alkali metals such as MnO, Mn ₃ O ₄ , ZrO ₂ , WO ₃ , TiO ₂ , In ₂ O ₃ , ZnO, NiO, HfO ₂ , Ta ₂ O ₅ , ReO ₃ , PbO ₂ ; metals other than alkaline earth metals Inorganic compounds such as oxides, ZnS, and ZnSe are desirable. In many cases, these oxides cause oxygen vacancies, which are suitable for hole injection. Further, amine compounds such as TPD and NPD, and compounds used as a hole injection layer and a hole transport layer in an organic EL device such as CuPc may be used. Moreover, what consists of two or more types of said compounds is desirable.

In the thin film transistor of the present invention, a gas barrier layer may be formed on the whole or a part of the outer peripheral surface of the element in consideration of the influence on the semiconductor layer such as oxygen and water contained in the atmosphere.
As the material for forming the gas barrier layer, known materials can be used, and examples thereof include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride, and polychlorotrifluoroethylene. Furthermore, the inorganic substance and organic substance which have the insulation illustrated as a material of an insulator layer can also be used.

Synthesis example 1
A solution prepared by dissolving 0.2 kg of 1,1-bis (4-bidoxyphenyl) ethane in 1.2 kg of a 12 wt% aqueous sodium hydroxide solution and 1.0 kg of methylene chloride was mixed and stirred while cooling. Then, phosgene gas was blown into the liquid at a rate of 1 L / min until the pH became 9 or less. The reaction solution was then allowed to stand to obtain a methylene chloride solution of an oligomer (PCO-E) having a degree of polymerization of 2 to 6 in the organic layer and having a chloroformate group at the molecular end.

A mechanical stirrer, a stirring blade, and a baffle plate were attached to the reaction vessel, and methylene chloride (140 mL) was added to the oligomer (310 mL). To this, p-tert-butylphenol (2.9 g) was added as a terminal terminator and stirred to ensure sufficient mixing. To this solution, the whole amount of a separately prepared monomer solution was added, and stirring was continued for 1 hour.
As the monomer solution, 185 mL of a 2N aqueous sodium hydroxide solution was prepared, cooled to room temperature or lower, 0.1 g of hydrosulfite, and 1,1-bis (4-hydroxyphenyl) ethane (Bis-E) 16 0.7 g was added and completely dissolved.

The resulting reaction mixture was diluted with 2 L of methylene chloride and 1 L of water and washed. The lower layer was separated, and further washed with 1 L of water, once with 1 L of 0.01N hydrochloric acid, and 3 times with 1 L of water. The obtained methylene chloride solution was dropped into warm water (70 ° C.) containing isopropyl alcohol, and the resulting precipitate was filtered and dried to obtain compound (1).

The structure of the compound (1) was confirmed by ¹ H-NMR spectrum.
Moreover, the reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (1) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 1
Glass of 25 × 20 × 1.1 mm size was used as a substrate, an ITO film was formed on the substrate with a thickness of 100 nm, and patterned using a photolithography method to form a transparent gate electrode (hereinafter referred to as ITO). A substrate provided with a film is called a transparent support substrate). The transparent support substrate was ultrasonically washed with isopropyl alcohol for 5 minutes, then washed with pure water for 5 minutes, further ultrasonically washed with isopropyl alcohol for 5 minutes, and then dried by blowing dry N ₂ gas. And finally, it was cleaned for 30 minutes with a UV ozone cleaning device [manufactured by Samco International Co., Ltd.].
0.25 g of the prepared compound (1) was added to 5 g of THF, and a 5 wt% polycarbonate solution was prepared by applying to a commercially available ultrasonic cleaner for 30 minutes. The polycarbonate solution was filtered through a 0.2 micron PTFE membrane filter, dropped onto the transparent support substrate, and spin-coated at 1500 rpm for 30 seconds to form a gate insulator layer having a thickness of 710 nm.

After the formation of the insulator layer, the organic semiconductor layer and the metal electrode were formed in the following manner under a series of vacuum environments by being fixed to a substrate holder of a commercially available vacuum deposition apparatus [ULVAC Co., Ltd.].
The transparent support substrate on which the polycarbonate layer was formed was fixed in a vacuum deposition apparatus and evacuated to 1 × 10 ⁻⁴ Pa or less. A tungsten boat containing pentacene was heated by energization to heat the deposition source to 400 ° C., and a pentacene thin film (semiconductor layer) having a thickness of 50 nm was provided on the outer surface of the laminated structure at a deposition rate of 0.05 nm / s. Finally, a gold film having a thickness of 50 nm was formed through a metal mask, so that a source electrode and a drain electrode that were not in contact with each other were formed so that the interval (channel length L) was 75 μm. At that time, the source electrode and the drain electrode were formed to have a width (channel width W) of 5 mm, and a thin film transistor having the structure of FIG. 2 was manufactured.

The film thickness and vapor deposition rate of the organic semiconductor layer and the metal electrode were controlled while monitoring the film thickness of the vapor deposited film by using a quartz-vibration film thickness meter (manufactured by ULVAC, Inc.) disposed in a vacuum chamber. Moreover, the film thickness of each obtained layer was measured with a stylus type film thickness meter, and it was confirmed that it coincided with the reading of the crystal vibration type film thickness meter.

A gate voltage of 0 to −100 V is applied to the gate electrode of the obtained thin film transistor, a current of 5 to −100 V is applied between the source and the drain to pass a current, an on / off ratio, a threshold voltage, and a field effect mobility. μ was evaluated. As a result, the on / off ratio of the current between the source and drain electrodes in the current saturation region was 9.3 × 10 ⁵ , the threshold voltage was −23 V, and the field-effect mobility μ was 1.1 cm ² / Vs. Application of each voltage and measurement of the current between the source and drain electrodes were performed using a semiconductor characteristic evaluation system (4200SCS manufactured by Keithley Instruments Co., Ltd.).

The obtained thin film transistor operated as a p-type transistor because electrons were induced in the channel region (between source and drain) of the organic semiconductor layer. The field effect mobility μ was calculated using the following formula (A).
I _D = (W / 2L) · Cμ · (V _G −V _T ) ² (A)
(Where _ID is the source-drain current, W is the channel width, L is the channel length, C is the capacitance per unit area of the gate insulator layer, V _T is the gate threshold voltage, and V _G is the gate voltage. is there.)

Further, the THF solubility of the compound (1) used for the insulator layer of the thin film transistor was evaluated. Specifically, 1 g of the compound (1) and 19 g of THF are added to a sample bottle that can be sealed, shaken at room temperature (23 ° C.) under normal pressure conditions until dissolved for 24 hours, and then the sample bottle is visually observed. The presence or absence of insoluble matter was evaluated. The results are shown in Table 1. The THF solubility was evaluated as “◯” when there was no insoluble matter. Moreover, when an insoluble matter was clearly confirmed and when an insoluble matter such as fine dust was confirmed, a uniform insulator layer could not be finally formed. Moreover, when there was a difference in solubility due to the difference in resin shape (pellets, flakes, etc.), the one with poor solubility was used as a criterion.

Since the dissolution of the compound (1) was confirmed, the sample bottle containing the THF solution of the compound (1) was allowed to stand for another week, and the presence or absence of gelation was visually confirmed in the same manner as above, and the THF dissolution stability Evaluated. The results are shown in Table 1. The THF dissolution stability was evaluated as “◯” when gelation could not be confirmed, and as “x” when gelation could be confirmed.
Furthermore, cyclohexanone and toluene solubility were also evaluated in the same manner as the THF solubility evaluation. The results are shown in Table 1.

Example 2
A solution prepared by dissolving 0.2 kg of 2,2-bis (4-bidroxyphenyl) propane in 1.3 kg of a 10 wt% aqueous sodium hydroxide solution and 1.0 kg of methylene chloride was mixed and stirred while cooling. Then, phosgene gas was blown into the liquid at a rate of 1 L / min until the pH became 9 or less. The reaction solution was then allowed to stand to obtain a methylene chloride solution of an oligomer (PCO-A) having a degree of polymerization of 2 to 6 in the organic layer and having a chloroformate group at the molecular end.

A mechanical stirrer, a stirring blade, and a baffle plate were attached to the reaction vessel, and methylene chloride (160 mL) was added to the oligomer (310 mL). To this, p-tert-butylphenol (2.3 g) was added as a terminal terminator and stirred to ensure sufficient mixing. To this solution, the whole amount of a separately prepared monomer solution was added, and stirring was continued for 1 hour.
As the monomer solution, 195 mL of 2N aqueous sodium hydroxide solution was prepared and cooled to room temperature or lower, and 0.1 g of hydrosulfite and 29 g of bis (2-thio (4-hydroxyphenyl) ethyloxy) -methane were added. And prepared by complete dissolution.

The resulting reaction mixture was diluted with 2 L of methylene chloride and 1 L of water and washed. The lower layer was separated, and further washed with 1 L of water, once with 1 L of 0.01N hydrochloric acid, and 3 times with 1 L of water. The obtained methylene chloride solution was dropped into warm water (70 ° C.) containing isopropyl alcohol, and the resulting precipitate was filtered and dried to obtain the following compound (2) as a copolymer.

The structure of compound (2) was confirmed by ¹ H-NMR spectrum.
Moreover, the reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (2) having a concentration of 0.5 g / dl was 0.51 dl / g.

A thin film transistor was prepared and evaluated in the same manner as in Example 1 except that the following compound (2) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (2) was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (3) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (3) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (3) having a concentration of 0.5 g / dl was 1.3 dl / g.

Example 4
A thin film transistor was prepared and evaluated in the same manner as in Example 1 except that the following compound (4) was used instead of the compound (1) and an insulator layer was laminated. Moreover, the THF, cyclohexanone and toluene solubility of the compound (4) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (4) having a concentration of 0.5 g / dl was 0.70 dl / g.

Example 5
A thin film transistor was prepared and evaluated in the same manner as in Example 1 except that the following compound (5) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (5) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (5) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 6
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (6) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (6) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (6) having a concentration of 0.5 g / dl was 1.7 dl / g.

Example 7
A thin film transistor was prepared and evaluated in the same manner as in Example 1 except that the following compound (7) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (7) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (7) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 8
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (8) was used instead of the compound (1) to laminate an insulator layer. Further, the THF, cyclohexanone and toluene solubility of the compound (8) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (8) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 9
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (9) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (9) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (9) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 10
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (10) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (10) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (10) having a concentration of 0.5 g / dl was 0.40 dl / g.

Example 11
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (11) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (11) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (11) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 12
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (12) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (12) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (12) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 13
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (13) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (13) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (13) having a concentration of 0.5 g / dl was 0.50 dl / g.

Example 14
A thin film transistor was fabricated and evaluated in the same manner as in Example 1 except that the following compound (14) was used instead of the compound (1) and an insulator layer was laminated. Further, the THF, cyclohexanone and toluene solubility of the compound (14) was evaluated in the same manner as in Example 1. The results are shown in Table 1.
The reduced viscosity [η _SP / C] at 20 ° C. of a methylene chloride solution of the compound (14) having a concentration of 0.5 g / dl was 0.50 dl / g.

Comparative Example 1
A thin film transistor was prepared and evaluated in the same manner as in Example 1 except that an insulator layer was laminated using bisphenol A-type polycarbonate resin (Taflon A2200, manufactured by Idemitsu Kosan Co., Ltd.) instead of the compound (1). However, the bis-A type polycarbonate resin has low solubility in THF, and a uniform insulator layer could not be formed. For this reason, the fabricated transistor could not obtain FET characteristics.
Further, the solubility of bis-A in THF, cyclohexanone and toluene was evaluated in the same manner as in Example 1. The results are shown in Table 1.

As can be seen from Table 1, it was confirmed that the compounds (1) to (14) which are polycarbonates of the present invention have sufficient solubility in THF solvent. In addition, it was confirmed that the polycarbonate material having high solubility in THF has sufficient solubility to form a thin film transistor insulating layer in other non-halogen solvents.

By the way, it is known that the state of the interface between the insulator layer and the organic semiconductor layer constituting the organic TFT affects the mobility, threshold voltage, and on / off ratio ("Applied Physics" Vol. 77, No. 4). (2008) 432-437). Although the state of the interface between the insulator layer and the organic semiconductor layer in the organic TFT of the present invention has not been elucidated, for example, the surface energy of the insulator layer affecting the orientation of the organic semiconductor, the surface of the insulator layer affecting the off-current The cleanliness, the continuity of the insulator layer (the occurrence of cracks, etc.) and the smoothness that affects the adhesion with the organic semiconductor layer, etc. may affect the performance of the organic TFT.

On the other hand, there are differences in mobility, threshold voltage, and on / off ratio of each example shown in Table 1, and Ar in formula (I) is represented by formula (3) having an asymmetric structure. The organic TFT using the polycarbonate which is a bonding group or the polycarbonate which is a bonding group represented by the formula (4) has shown better performance.

In addition, in the polycarbonate copolymer composed of the repeating units of the formula (II) and the formula (III), both Ar ² and Ar ³ are a linking group represented by the formula (2), and are introduced to increase the solubility. When the repeating unit is 9,9-fluorenylidene group or the formula (6a), better performance is shown.

On the other hand, Ar in formula (I) is a linking group represented by formula (2), X is a linking group represented by formula (2a), R ³ and R ⁴ are hydrogen atoms, In the case of a polycarbonate which is a linking group which is a cycloalkylidene group in which R ⁵ and R ⁶ are bonded to each other, and a polycarbonate which is a linking group represented by the formula (2b) having a similar structure, the performance is excellent. The mobility tends to be small. This may be because the interface state described above is reflected.

It has been confirmed that the thin film transistor including the polycarbonate of the present invention in the insulator layer exhibits sufficient performance for applications such as electronic paper and liquid crystal displays.

In addition, in this-application Example, THF solubility is evaluated, However, THF solubility is only the reference | standard which evaluates "solubility in a non-halogen-type solvent." If the polycarbonate of the present invention is used, the coating solvent is not limited to THF.
Non-halogen solvents other than THF include aromatic solvents such as benzene, toluene and xylene, ketones such as cyclohexanone, ethers such as dioxane, amides such as dimethylformamide, dimethyl sulfoxide and diethylformamide. Since the polycarbonate of the present invention can be dissolved in any of these solvents, the insulator layer can be formed by a coating method.

The thin film transistor of the present invention can be suitably used for driving circuits such as electronic paper and liquid crystal display, various sensors, authentication tags, and the like.

Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will recognize that these exemplary embodiments and / or embodiments are substantially without departing from the novel teachings and advantages of the present invention. It is easy to make many changes to the embodiment. Accordingly, many of these modifications are within the scope of the present invention.
The entire contents of the documents described in this specification are incorporated herein.

Claims

In a thin film transistor in which at least three terminals of a gate electrode, a source electrode and a drain electrode, an insulator layer and a semiconductor layer are provided on a substrate, and a source-drain current is controlled by applying a voltage to the gate electrode.
The insulator layer is a layer laminated by a coating method and has a solubility in at least one solvent selected from tetrahydrofuran, cyclohexanone and toluene of 5% by weight or more, and is represented by the following formula (I) A thin film transistor containing a polycarbonate composed of units.

(In the formula, Ar is a divalent aromatic group.)
The thin film transistor according to claim 1, wherein Ar in the formula (I) is a bonding group represented by the following formula (1) or (2).

(In the formula, R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(Wherein R 3 and R 4 are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom.
X represents —O—, —S—, —SO—, —SO 2 —, —CO—, 9,9-fluorenylidene group, represented by the following formula (2a), (2b), (2c), or (2d) It is a linking group represented. )

(Wherein R 5 and R 6 are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R 5 and R 6 are bonded to each other. A cycloalkylidene group having 4 to 12 carbon atoms may be formed.)

(In the formula, each R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and at least one of R is an alkyl group having 1 to 3 carbon atoms.)

(The linking group represented by the formula (2c) may be o-, m-, or p-)

(In the formula, two of R 7 to R 12 are bonding groups, and R 7 to R 12 that are bonding groups are each a single bond or an alkylene group, and each of R 7 to R 12 that is not a bonding group is It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
The thin film transistor according to claim 1, wherein Ar in the formula (I) is a bonding group represented by the following formula (3) having an asymmetric structure.

(Wherein R 13 and R 14 are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom.
R 15 and R 16 are different from each other, and each is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. )
Carbon in which Ar in Formula (I) is a linking group represented by Formula (2), X is a linking group represented by Formula (2a), and R 5 and R 6 are bonded to each other. The thin film transistor according to claim 2, wherein the thin film transistor is a cycloalkylidene group having a number of 4 to 12.
The thin film transistor according to claim 1 or 2, wherein Ar in the formula (I) is a bonding group represented by the following formula (4).

(In the formula, X is the same as the formula (2).
R 17 and R 18 are each an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. )
The thin film transistor according to claim 1, wherein Ar in the formula (I) is a bonding group represented by the following formula (5).

(Wherein R 19 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and R 20 is an aryl group having 6 to 12 carbon atoms, respectively. And an aliphatic hydrocarbon group having 4 to 12 carbon atoms.)
Ar in the formula (I) has a linking group represented by the following formulas (6a), (6b) and (6c), and the number of these linking groups is (6a + 6c) / (6a + 6b + 6c) = 0.05-0. The thin film transistor according to claim 1, satisfying .95.

(In the formula, X is the same as the formula (2).
R is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. )
In a thin film transistor in which at least three terminals of a gate electrode, a source electrode and a drain electrode, an insulator layer and a semiconductor layer are provided on a substrate, and a source-drain current is controlled by applying a voltage to the gate electrode.
The insulator layer is a layer laminated by a coating method and has a solubility in at least one solvent selected from tetrahydrofuran, cyclohexanone and toluene of 5% by weight or more, and is represented by the following formula (II) A thin film transistor containing a polycarbonate comprising a copolymer of a unit and a repeating unit represented by the following formula (III).

(In the formula, Ar 2 and Ar 3 are each a linking group represented by the following formula (1) or (2), and Ar 2 and Ar 3 are linking groups different from each other.)

(In the formula, R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(Wherein R 3 and R 4 are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom.
X represents —O—, —S—, —SO—, —SO 2 —, —CO—, 9,9-fluorenylidene group, represented by the following formula (2a), (2b), (2c), or (2d) It is a linking group represented. )

(Wherein R 5 and R 6 are each a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and R 5 and R 6 are bonded to each other. A cycloalkylidene group having 4 to 12 carbon atoms may be formed.)

(In the formula, each R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and at least one of R is an alkyl group having 1 to 3 carbon atoms.)

(The linking group represented by the formula (2c) may be o-, m-, or p-)

(In the formula, two of R 7 to R 12 are bonding groups, and R 7 to R 12 that are bonding groups are each a single bond or an alkylene group, and each of R 7 to R 12 that is not a bonding group is It is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
The thin film transistor according to any one of claims 1 to 8, wherein the polycarbonate has a solubility in tetrahydrofuran of 7% by weight or more.
The organic thin film transistor according to any one of claims 1 to 9, wherein the semiconductor layer is an organic semiconductor.