JP5187737B2 - FIELD EFFECT TRANSISTOR, PROCESS FOR PRODUCING THE SAME, COMPOUND USED FOR THE SAME, AND INK FOR SEMICONDUCTOR DEVICE - Google Patents

Description

  The present invention relates to a field effect transistor. More specifically, the present invention relates to a field effect transistor using a specific organic heterocyclic compound as a semiconductor material and a method for manufacturing the same.

  A field effect transistor generally has a structure in which a semiconductor material on a substrate is provided with a source electrode, a drain electrode, and a gate electrode or the like through these electrodes and an insulator layer. Besides being used, it is also widely used for switching elements. Currently, inorganic semiconductor materials centering on silicon are used for field effect transistors, and thin film transistors formed on a substrate such as glass using amorphous silicon are used for displays and the like. When such an inorganic semiconductor material is used, it is necessary to process the field effect transistor at a high temperature or in a vacuum, and the cost is very high because it requires expensive equipment investment and a lot of energy for manufacturing. Become. In these, since the substrate is exposed to a high temperature during the production of the field effect transistor, a substrate having insufficient heat resistance such as a film or plastic cannot be used as the substrate, and its application range is limited.

On the other hand, research and development of field effect transistors using organic semiconductor materials that do not require high-temperature processing during the manufacture of field effect transistors have been conducted. By using an organic material, manufacturing by a low temperature process becomes possible, and the range of substrate materials that can be used is expanded. As a result, it has become possible to produce a field effect transistor that is more flexible, lighter, and less likely to break. Furthermore, in the field effect transistor creation process, it is possible to manufacture a large-area field effect transistor at low cost by applying a solution containing an organic semiconductor material or adopting a printing method such as inkjet. There is also.
However, many of the compounds conventionally used as organic semiconductor materials are insoluble or extremely insoluble in organic solvents, and it is not possible to use an inexpensive method such as the above-described coating or ink jet printing. A thin film had to be formed on a semiconductor substrate by means of high-cost vacuum deposition or the like, and there were almost no materials (compounds) practically suitable for printing. Moreover, even if it is a material which melt | dissolves in an organic solvent, the semiconductor characteristic is not practical, for example, there was only the material with low carrier mobility, for example. However, it is important to develop a semiconductor material that enables the production of a semiconductor by coating or printing, and several studies have been made.
Patent Document 1 discloses that a pentacene thin film and a transistor are formed by dispersing pentacene in an organic solvent and then applying the dispersion to a silicon substrate heated to 100 ° C.
Patent Document 2 discloses a method for producing an organic transistor using a porphyrin-based compound and the above-described coating method.
Patent Document 3 discloses benzodiselenophene (a compound in which X ¹ and X ² are selenium atoms and R ¹ and R ² are hydrogen atoms in the following formula (1)) and benzodithiophene (the following formula ( In 1), a field effect transistor using an aryl derivative of a compound in which X ¹ and X ² are sulfur atoms and R ¹ and R ² are hydrogen atoms is disclosed.
Non-Patent Document 1 discloses an organic field effect transistor in which a specific substituent is introduced and a pentacene derivative or the like soluble in an organic solvent is used.
Non-Patent Document 2 discloses benzodiselenophene (a compound in which X ¹ and X ² are selenium atoms and R ¹ and R ² are hydrogen atoms in the following formula (1)) and benzodithiophene (described below). A field effect transistor using an aryl derivative of the formula (1) in which X ¹ and X ² are sulfur atoms and R ¹ and R ² are hydrogen atoms is disclosed.
However, an example in which the alkyl derivative is used for a field effect transistor is not known.

JP 2005-281180 A JP 2005-322895 A JP 2005-154371 A J. et al. AM. CHEM. SOC. 2005, 127, 4986-4987 J. et al. Am. Chem. Soc. 2004, 126, 5084-5085

  It is an object of the present invention to provide a field effect transistor having excellent stability using an organic semiconductor material, which is dissolved in an organic solvent, has practical printability, and has excellent semiconductor properties such as carrier mobility. To do.

  As a result of intensive investigations to solve the above problems, the present inventors have found that when a compound having a specific structure is used as a semiconductor material, the compound is soluble in an organic solvent and has printing characteristics. The inventors have found that a field effect transistor that can be produced by the above method and that exhibits excellent carrier mobility can be obtained, and the present invention has been completed.

That is, the present invention
[1]. A field effect transistor comprising a compound represented by the following formula (1) as a semiconductor material.

(In ^the formula (1), ^{X 1} and ^{X 2} are identical and represent an unsubstituted or substituted C4-C20 aliphatic hydrocarbon group, respectively .R ¹ and ^{R 2} are independently represents a sulfur atom or selenium atom .)
[ 2 ]. The field effect transistor according to [1], wherein X ¹ and X ² in Formula (1) are both sulfur atoms.
[ 3 ]. The field effect transistor according to [1] or [2] , wherein R ¹ and R ² in formula (1) are each independently an unsubstituted aliphatic hydrocarbon group.
[ 4 ]. The field effect transistor according to [ 3 ], wherein R ¹ and R ² in formula (1) are each independently a saturated aliphatic hydrocarbon group.
[ 5 ]. The field effect transistor according to [ 4 ], wherein R ¹ and R ² in formula (1) are each independently a linear aliphatic hydrocarbon group.
[ 6 ]. An ink for producing a semiconductor device, comprising the compound of formula (1) according to [1] .
[ 7 ]. The manufacturing method of the field effect transistor characterized by forming the semiconductor layer by apply | coating the ink for semiconductor device preparation as described in [ 6 ] on a board | substrate, and making it dry.
[ 8 ]. [ 7 ] The method for producing a field effect transistor according to [ 7 ], wherein the semiconductor layer is formed in the atmosphere.
[ 9 ]. The method for producing a field effect transistor according to [ 7 ] or [ 8 ], wherein heat treatment is performed after forming the semiconductor layer.
[ 10 ]. The method for producing a field effect transistor according to [ 9 ], wherein the heat treatment temperature is 40 to 120 ° C.
[ 11 ]. A compound represented by the following formula [ 1 ].

(In ^the formula (1), ^{X 1} and ^{X 2} are identical and represent an unsubstituted or substituted C4-C20 aliphatic hydrocarbon group each independently .R ¹ and ^{R 2} represents a sulfur atom or selenium atom. )
[ 12 ]. The compound according to [11] , represented by the following formula (3).

(Wherein (in 3), ^{R 5} and ^{R 6} each independently represent a C2-C 18 aliphatic hydrocarbon group, ^{X 1} and ^{X 2} are the same. Representing a sulfur atom or selenium atom)

  By using a compound having a specific structure represented by the above formulas (1) to (3) as a semiconductor material, it has high solubility in an organic solvent and has printability, so that it is prepared by a method such as coating or printing. Thus, it was found that a field effect transistor having excellent carrier mobility and excellent stability could be obtained, and an excellent field effect transistor could be provided.

The present invention will be described in detail.
The present invention is an organic field effect transistor using a specific organic compound as a semiconductor material, and the compound represented by the above formulas (1) to (3) is used as the organic compound. The compounds represented by the above formulas (1) to (3) will be described below.

The formula (1) to (3), ^{X 1} and ^{X 2} are each independently a sulfur atom, a selenium atom or a tellurium atom. Preferred are a sulfur atom and a selenium atom, and more preferred is a sulfur atom.
In the above formula (1), R ¹ and R ² each independently represents an unsubstituted or substituted C1-C36 aliphatic hydrocarbon group. In the above formula (2), R ³ and R ⁴ each independently represent a C4-C34 aliphatic hydrocarbon group. In said formula (3), R < ⁵ > and R < ⁶ > represents a C2-C32 aliphatic hydrocarbon group each independently.
Examples of the aliphatic hydrocarbon group include saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon groups. A linear or branched aliphatic hydrocarbon group is preferable, and a linear aliphatic hydrocarbon group is more preferable.
Carbon number is C1-C36 normally, Preferably it is C2-C24, More preferably, it is C4-C20.
Examples of linear or branched saturated aliphatic hydrocarbon groups include methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, t-butyl, n-pentyl, iso-pentyl, t-pentyl, sec-pentyl, n-hexyl, iso-hexyl, n-heptyl, sec-heptyl, n-octyl, n-nonyl, sec-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n- Tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, docosyl, n-pentacosyl, n-octacosyl, n-tricontyl, 5- (n-pentyl) decyl, heneicosyl , Tricosyl, tetracosyl, hexacosyl, heptacosyl, nonacosyl, n-tria Pentyl, Sukuariru, dotriacontyl, hexamethylene triacontyl, and the like.
Examples of the cyclic saturated aliphatic hydrocarbon group include cyclohexyl, cyclopentyl, adamantyl, norbornyl and the like.
Examples of linear or branched unsaturated aliphatic hydrocarbon groups include vinyl, allyl, eicosadienyl, 11,14-eicosadienyl, geranyl (trans-3,7-dimethyl-2,6-octadien-1-yl), Farnesyl (trans, trans-3,7,11-trimethyl-2,6,10-dodecatrien-1-yl), 4-pentenyl, 1-propynyl, 1-hexynyl, 1-octynyl, 1-decynyl, 1- Examples include undecynyl, 1-dodecynyl, 1-tetradecynyl, 1-hexadecynyl, 1-nonadecynyl and the like.
Of the straight-chain, branched-chain and cyclic aliphatic hydrocarbon groups, preferred are straight-chain or branched-chain groups, and more preferred are straight-chain groups.
The saturated or unsaturated aliphatic hydrocarbon group includes alkyl representing a saturated one, alkenyl containing a carbon-carbon double bond, and alkynyl containing a carbon-carbon triple bond. Examples of the aliphatic hydrocarbon residue include those in which these are combined, that is, a case where a carbon-carbon double bond and a carbon-carbon triple bond are simultaneously contained in a part of the aliphatic hydrocarbon group. More preferred is alkyl or alkynyl, and further preferred is alkyl.
When the aliphatic hydrocarbon residue represented by R ^{1 to} R ⁴ represented by the above formula (1) or formula (2) is an unsaturated aliphatic hydrocarbon group, the unsaturated carbon-carbon bond is A position where R ^{1 to} R ⁴ are conjugated with a substituted benzene ring, that is, one in which one carbon atom of an unsaturated carbon-carbon bond is directly connected to the benzene ring is more preferable. In this case as well, alkynyl is more preferable than alkenyl as described above.

The substituted aliphatic hydrocarbon group means a group in which any position of the above aliphatic hydrocarbon group is substituted with any number and any kind of substituent.
Examples of the substituent include, but are not limited to, an aliphatic hydrocarbon group which may have a substituent (for example, an aromatic group (for example, a phenyl group, a naphthyl group, a pyridyl group, a pyrazyl group, a furyl group, Thienyl group, carbazolyl group, etc.), halogen atom (fluorine, chlorine, bromine, iodine, etc.), nitro group, alkoxyl group, alkyl-substituted amino group, aryl-substituted amino group, unsubstituted amino group, acyl group, alkoxycarbonyl group, cyano Group, isocyano group, nitro group, thioalkyl group, etc. Among them, aromatic group, halogen atom, hydroxyl group and the like are preferable.
Of the above groups, R ¹ and R ² in the formula (1) are preferably an unsubstituted unsaturated aliphatic hydrocarbon group or an unsubstituted linear saturated aliphatic hydrocarbon group containing a carbon-carbon triple bond. The latter is more preferable. The carbon number in this case is as described above. R ¹ and R ² are preferably the same group rather than independent groups. When the carbon-carbon triple bond is included, it is preferable that one triple bond is included at a position conjugated with the benzene ring.
Moreover, what is preferable as a compound represented by Formula (1) is a compound represented by Formula (2) or Formula (3). R ³ in formula (2), R ⁵ in formula (3) corresponds to R ¹ in formula (1), R ⁴ in formula (2), and R ⁶ in formula (3) are in formula (1). each corresponding to R ^2. Accordingly, preferred groups and the like may be the same as the corresponding R ¹ and R ² in the formula (1).

In the above formula (3), the unsubstituted or substituted aliphatic hydrocarbon group represented by R ⁵ and R ⁶ is R ¹ , R ² , R in the compound represented by the above formula (1) or formula (2). ^{In 3} and R ⁴ , the carbon atom bonded to the benzene ring and the carbon atom bonded to the carbon atom form a carbon-carbon triple bond. Therefore, specific examples of the aliphatic hydrocarbon group represented by R ³ and R ⁴ include the same groups as long as they are C1-C34 among the groups listed as R ¹ and R ² above.
Moreover, the same group can be mention | raise | lifted as a preferable group, if it is comprised by C1-C34. Also according to the ^R 1 to R ⁴ for a range of carbon atoms.

The compound represented by the above formula (1) can be synthesized, for example, by a known method described in Non-Patent Document 2. For example, it can also be obtained according to the method described in Patent Document 3.
That is, the raw material 1,4-dibromobenzene (4) is heated together with iodine in sulfuric acid to obtain the following formula (5). In the presence of a catalyst, trimethylsilylacetylene (TMS acetylene) is subjected to a Sonogashira coupling reaction, and the following formula ( 6) is obtained. After the following formula (6) is lithiated with t-butyllithium, the following formula (207) is obtained by reacting and purifying with sulfur or selenium. This is reacted with a halide such as iodine chloride to obtain a halogen compound such as diiodide (208), and this diiodide (208) and an acetylene derivative are allowed to act to carry out a coupling reaction, whereby the above formula (3) To obtain a compound of
Further, the obtained compound of the formula (3) is reduced (hydrogenated) by a conventional method, whereby in the above formula (1), R ¹ or R ² is an unsaturated aliphatic hydrocarbon group (alkenyl) or saturated A compound which is an aliphatic hydrocarbon group (alkyl) is obtained. When X ¹ and X ² in the compound represented by the above formula (3) are selenium atoms, the compound of the above formula (2) is obtained in the same manner.
The following formula (3) showed a coupling reaction between the following formula (4) and an acetylene derivative, but the coupling reaction with the ethylene derivative proceeded in the same manner. In this case, the carbon- Instead of a carbon triple bond, an alkenyl derivative is obtained in which this moiety is a carbon-carbon double bond. This alkenyl compound is also included in the compound of the above formula (1).
If the conditions for the reduction reaction of the compound of the following formula (3), for example, the type and amount of the reaction reagent used in the reduction reaction, the reaction solvent, and a combination thereof are appropriately selected, the reduction reaction proceeds to the carbon-carbon double bond. It is possible to stop in the state of being allowed to proceed, or to proceed until saturated aliphatic hydrocarbons are obtained.

(In the compounds of the above formulas (207) and (208), X ¹ and X ² represent the same meaning as in the above formula (1).)

  The method for purifying the compounds represented by the above formulas (1) to (3) is not particularly limited, and known methods such as recrystallization, column chromatography, and vacuum sublimation purification can be employed. Moreover, you may use these methods in combination as needed.

  Table 1 below shows specific examples of the compounds represented by the above formulas (1) to (3). Ph represents a phenyl group, Np represents a naphthyl group, and Th represents a thienyl group. For convenience, the compounds in the table are expressed based on the compound represented by the above formula (1).

  A field effect transistor (hereinafter sometimes abbreviated as FET) of the present invention has two electrodes in contact with a semiconductor, that is, a source electrode and a drain electrode. It is controlled by a voltage applied to another electrode called.

  In general, a field-effect transistor often has a structure in which a gate electrode is insulated by an insulating film (Metal-Insulator-Semiconductor: MIS structure). An insulating film using a metal oxide film is called a MOS structure. In addition, there is a structure in which a gate electrode is formed via a Schottky barrier (MES structure), but in the case of an FET using an organic semiconductor material, a MIS structure is often used.

Hereinafter, although the field effect transistor of this invention is demonstrated in detail using figures, this invention is not limited to these structures.
FIG. 1 shows some embodiments of the field effect transistor of the present invention. In each example, 1 represents a source electrode, 2 represents a semiconductor layer, 3 represents a drain electrode, 4 represents an insulator layer, 5 represents a gate electrode, and 6 represents a substrate. In addition, arrangement | positioning of each layer and an electrode can be suitably selected according to the use of an element. A to D are called lateral FETs because a current flows in a direction parallel to the substrate. A is called a bottom contact structure, and B is called a top contact structure. C is a structure often used for producing an organic single crystal FET. A source and drain electrodes and an insulator layer are provided on a semiconductor layer, and a gate electrode is further formed thereon. D has a structure called a top & bottom contact type transistor. E is a schematic diagram of an FET having a vertical structure, that is, a static induction transistor (SIT). According to this SIT structure, a large amount of carriers can move at a time because the current flow spreads in a plane. Further, since the source electrode and the drain electrode are arranged vertically, the distance between the electrodes can be reduced, so that the response is fast. Therefore, it can be preferably applied to uses such as flowing a large current or performing high-speed switching. In FIG. 1, E does not indicate a substrate, but in the normal case, a substrate is provided outside the source and drain electrodes represented by 1 and 3 in FIG. 1E.

Each component in each embodiment will be described.
The substrate 6 needs to be able to hold each layer formed thereon without peeling off. For example, insulating materials such as resin plates and films, paper, glass, quartz, and ceramics, materials in which an insulating layer is formed on a conductive substrate such as metal and alloy by coating, materials made of various combinations such as resin and inorganic materials, etc. Can be used. Examples of the resin film that can be used include polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyamide, polyimide, polycarbonate, cellulose triacetate, polyetherimide, and the like. When a resin film or paper is used, the semiconductor element can be made flexible, flexible and lightweight, and practicality is improved. The thickness of the substrate is usually 1 μm to 10 mm, preferably 5 μm to 5 mm.

A conductive material is used for the source electrode 1, the drain electrode 3, and the gate electrode 5. For example, platinum, gold, silver, aluminum, chromium, tungsten, tantalum, nickel, cobalt, copper, iron, lead, tin, titanium, indium, palladium, molybdenum, magnesium, calcium, barium, lithium, potassium, sodium, etc. And alloys containing them; conductive oxides such as InO ₂ , ZnO ₂ , SnO ₂ , ITO; conductive polymer compounds such as polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene vinylene, polydiacetylene; silicon, germanium, Semiconductors such as gallium arsenide; carbon materials such as carbon black, fullerene, carbon nanotube, and graphite can be used. Further, the conductive polymer compound or the semiconductor may be doped. As the dopant at that time, for example, acids such as hydrochloric acid, sulfuric acid and sulfonic acid, Lewis acids such as PF ₅ , AsF ₅ and FeCl ₃ , halogen atoms such as iodine, metal atoms such as lithium, sodium and potassium are used. It is done. In addition, a conductive composite material in which carbon black, gold, platinum, silver, copper, or other metal particles are dispersed in the above material may be used.
A wiring is connected to each of the electrodes 1, 3, and 5, and the wiring is also made of substantially the same material as the electrode.

An insulating material is used for the insulator layer 4. For example, polymers such as polyparaxylylene, polyacrylate, polymethyl methacrylate, polystyrene, polyvinylphenol, polyamide, polyimide, polycarbonate, polyester, polyvinyl alcohol, polyvinyl acetate, polyurethane, polysulfone, epoxy resin, phenol resin, and combinations thereof Copolymers; oxides such as silicon dioxide, aluminum oxide, titanium oxide and tantalum oxide; ferroelectric oxides such as SrTiO ₃ and BaTiO ₃ ; nitrides such as silicon nitride and aluminum nitride; sulfides; fluorides and the like Or a polymer in which particles of these dielectrics are dispersed can be used. The film thickness of the insulator layer 4 varies depending on the material, but is usually 0.1 nm to 100 μm, preferably 0.5 nm to 50 μm, more preferably 5 nm to 10 μm.

As the material of the semiconductor layer 2, compounds represented by the above formulas (1) to (3) are used. As the semiconductor material, an alkyl derivative is preferable to the alkenyl derivative and alkynyl derivative in the above formula (1).
As a material of the semiconductor layer 2, several kinds of compounds represented by the above formulas (1) to (3) may be mixed and used, but the compounds represented by the formulas (1) to (3) may be used in a total amount of 50. It is necessary to contain not less than wt%, preferably not less than 80 wt%, more preferably not less than 95 wt%. In order to improve the characteristics of the field effect transistor or to impart other characteristics, other organic semiconductor materials and various additives may be mixed as necessary. The semiconductor layer 2 may be composed of a plurality of layers.
The thickness of the semiconductor layer 2 is preferably as thin as possible without losing necessary functions. In lateral field effect transistors as shown in A, B, and D, if the film thickness exceeds a predetermined value, the characteristics of the semiconductor element do not depend on the film thickness, while the leakage current increases as the film thickness increases. Therefore, the film thickness is preferably in an appropriate range. The film thickness of the semiconductor layer is usually from 0.1 nm to 10 μm, preferably from 0.5 nm to 5 μm, more preferably from 1 nm to 3 μm in order to exhibit a function that requires a semiconductor.

In the field effect transistor of the present invention, other layers can be provided between the above-described layers or on the outer surface of the semiconductor element as necessary. For example, if a protective layer is formed directly on the semiconductor layer or via another layer, the influence of outside air such as humidity can be reduced, and the ON / OFF ratio of the device can be increased. There is also an advantage that the mechanical characteristics can be stabilized.
Although it does not specifically limit as a material of a protective layer, For example, the film | membrane which consists of various resins, such as acrylic resins, such as an epoxy resin and polymethylmethacrylate, polyurethane, polyimide, polyvinyl alcohol, a fluororesin, polyolefin, silicon oxide, aluminum oxide, A film made of a dielectric such as an inorganic oxide film or a nitride film, such as silicon nitride, is preferably used, and a resin (polymer) having a low oxygen or moisture permeability and a low water absorption rate is particularly preferable. In recent years, protective materials developed for organic EL displays can also be used. Although the film thickness of a protective layer can employ | adopt arbitrary film thickness according to the objective, it is 100 nm-1 mm normally.

  In addition, it is possible to improve device characteristics by performing surface treatment in advance on a substrate or an insulator layer on which a semiconductor layer is stacked. For example, by adjusting the degree of hydrophilicity / hydrophobicity of the substrate surface, the film quality of the film formed thereon can be improved. In particular, the characteristics of organic semiconductor materials can vary greatly depending on the state of the film, such as molecular orientation. Therefore, the surface treatment on the substrate or the like controls the molecular orientation at the interface between the substrate and the semiconductor layer to be formed thereafter, and reduces the trap sites on the substrate and the insulator layer. It is considered that characteristics such as carrier mobility are improved. The trap site refers to a functional group such as a hydroxyl group present in an untreated substrate. When such a functional group is present, electrons are attracted to the functional group, and as a result, carrier mobility is lowered. . Therefore, reducing trap sites is often effective for improving characteristics such as carrier mobility. Examples of such substrate treatment include hydrophobization treatment with hexamethyldisilazane, cyclohexene, octadecyltrichlorosilane, acid treatment with hydrochloric acid, sulfuric acid, acetic acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, etc. Electrical treatment such as alkali treatment with ozone, ozone treatment, fluorination treatment, plasma treatment with oxygen and argon, Langmuir / Blodgett film formation process, other insulator and semiconductor thin film formation process, mechanical process, corona discharge, etc. Examples thereof include a rubbing treatment using a treatment or fibers.

  As a method of providing each layer in these embodiments, for example, a vacuum deposition method, a sputtering method, a coating method, a printing method, a sol-gel method, or the like can be appropriately employed. In consideration of cost and labor, it is preferable to use a coating method or a printing method using, for example, ink jet printing.

Next, the manufacturing method of the field effect transistor of the present invention will be described below with reference to FIG. 2, taking the bottom contact type field effect transistor (FET) shown in the embodiment example A of FIG.
This manufacturing method can be similarly applied to the field effect transistors of the other embodiments described above.

(Substrate and substrate processing)
The field effect transistor of the present invention is manufactured by providing various layers and electrodes necessary on the substrate 6 (see FIG. 2A). As the substrate, those described above can be used. It is also possible to perform the above-described surface treatment on this substrate. The thickness of the substrate 6 is preferably thin as long as necessary functions are not hindered. Although it varies depending on the material, it is usually 1 μm to 10 mm, preferably 5 μm to 5 mm. If necessary, the substrate may have an electrode function.

(Formation of gate electrode)
A gate electrode 5 is formed on the substrate 6 (see FIG. 2B). The electrode material described above is used as the electrode material. As a method for forming the electrode film, various methods can be used. For example, a vacuum deposition method, a sputtering method, a coating method, a thermal transfer method, a printing method, a sol-gel method, and the like are employed. It is preferable to perform patterning as necessary so as to obtain a desired shape during or after film formation. Various methods can be used as the patterning method, and examples thereof include a photolithography method in which patterning and etching of a photoresist are combined. Patterning can also be performed using a printing method such as ink jet printing, screen printing, offset printing, letterpress printing, soft lithography such as a microcontact printing method, and a combination of these methods. The thickness of the gate electrode 5 varies depending on the material, but is usually 0.1 nm to 10 μm, preferably 0.5 nm to 5 μm, more preferably 1 nm to 3 μm. Moreover, when it serves as a gate electrode and a board | substrate, it may be larger than said film thickness.

(Formation of insulator layer)
An insulator layer 4 is formed over the gate electrode 5 (see FIG. 2 (3)). As the insulator material, those described above are used. Various methods can be used to form the insulator layer 4. For example, spin coating, spray coating, dip coating, casting, bar coating, blade coating, etc., screen printing, offset printing, ink jet printing, vacuum deposition, molecular beam epitaxial growth, ion cluster beam method, ion plating Examples thereof include dry process methods such as a coating method, a sputtering method, an atmospheric pressure plasma method, and a CVD method. In addition, a method of forming an oxide film on a metal such as a sol-gel method or alumite on aluminum is employed.
In the portion where the insulator layer and the semiconductor layer are in contact, in order to satisfactorily orient the molecules constituting the semiconductor at the interface between the two layers, for example, the molecules of the compounds represented by the above formulas (1) to (3), A predetermined surface treatment can also be performed on the insulator layer. As the surface treatment method, the same surface treatment as that of the substrate can be used. The thickness of the insulator layer 4 is preferably as thin as possible without impairing its function. Usually, it is 0.1 nm-100 micrometers, Preferably it is 0.5 nm-50 micrometers, More preferably, it is 5 nm-10 micrometers.

(Formation of source electrode and drain electrode)
The source electrode 1 and the drain electrode 3 can be formed according to the case of the gate electrode 5 (see FIG. 2 (4)).

(Formation of semiconductor layer)
As described above, as the semiconductor material, an organic material containing a compound represented by the above formulas (1) to (3) or a mixture of several kinds of the compounds in a total amount of 50% by weight or more is used. Various methods can be used for forming the semiconductor layer. Formation method in vacuum process such as sputtering method, CVD method, molecular beam epitaxial growth method, vacuum deposition method, coating method such as dip coating method, die coater method, roll coater method, bar coater method, spin coating method, ink jet method In addition, it is roughly classified into formation methods in solution processes such as screen printing, offset printing, and microcontact printing. Hereinafter, a method for forming a semiconductor layer will be described in detail.

First, a method for obtaining an organic semiconductor layer by forming an organic material by a vacuum process will be described.
A method (vacuum deposition method) in which the organic material is heated in a crucible or a metal boat under vacuum and the evaporated organic material is attached (deposited) to a substrate (exposed portions of the insulator layer, the source electrode and the drain electrode). Preferably employed. Under the present circumstances, a vacuum degree is 1.0 * 10 < ^-1 > Pa or less normally, Preferably it is 1.0 * 10 <^-4> Pa or less. In addition, since the characteristics of the organic semiconductor layer (film) and hence the field effect transistor vary depending on the substrate temperature during vapor deposition, it is preferable to carefully select the substrate temperature. The substrate temperature during vapor deposition is usually 0 to 200 ° C, preferably 10 to 150 ° C. The deposition rate is usually 0.001 nm / second to 10 nm / second, preferably 0.01 nm / second to 1 nm / second. The film thickness of the organic semiconductor layer formed from an organic material is usually 0.1 nm to 10 μm, preferably 0.5 nm to 5 μm, more preferably 1 nm to 3 μm.
Instead of heating and evaporating the organic material for forming the organic semiconductor layer and attaching it to the substrate, a sputtering method in which accelerated ions such as argon collide with the material target to knock out material atoms and attach them to the substrate. It may be used.

  Next, a method for obtaining an organic semiconductor layer by forming an organic semiconductor material by a solution process will be described. The semiconductor material in the present invention is easily dissolved in an organic solvent, and practical semiconductor characteristics can be obtained by this solution process. Since the manufacturing method by coating does not require a manufacturing environment to be in a vacuum or a high temperature state, it is advantageous because a large-area field effect transistor can be realized at low cost, and is preferable among methods for manufacturing various semiconductor layers.

First, an ink for producing a semiconductor device is prepared by dissolving the compounds of the formulas (1) to (3) in a solvent. The solvent at this time is not particularly limited as long as the compound dissolves and a film can be formed on the substrate. The solvent is preferably an organic solvent, specifically, a halogeno hydrocarbon solvent such as chloroform, methylene chloride, or dichloroethane; an alcohol solvent such as methanol, ethanol, isopropyl alcohol, or butanol; an octafluoropentanol, pentafluoropropanol, or the like. Fluorinated alcohol solvents; ester solvents such as ethyl acetate, butyl acetate, ethyl benzoate and diethyl carbonate; aromatic hydrocarbon solvents such as toluene, xylene, benzene, chlorobenzene and dichlorobenzene; acetone, methyl ethyl ketone, methyl isobutyl ketone Ketone solvents such as cyclopentanone and cyclohexanone; amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; tetrahydrofuran, diisobuty Etc. can be used ether solvents such as ether. These can be used alone or in combination.
The concentration of the total amount of the compounds of the above formulas (1) to (3) or a mixture thereof in the ink varies depending on the type of solvent and the thickness of the semiconductor layer to be produced, but is preferably about 0.001% to 50%. Is about 0.01% to 20%.
Additives and other semiconductor materials can be mixed for the purpose of improving the film formability of the semiconductor layer and doping described later.
When ink is used, a material such as a semiconductor material is dissolved in the above solvent, and if necessary, a heat dissolution treatment is performed. Furthermore, the obtained solution is filtered using a filter to remove solids such as impurities, thereby obtaining an ink for producing a semiconductor device. When such an ink is used, the film formability of the semiconductor layer is improved, which is preferable for manufacturing the semiconductor layer.

  The ink for manufacturing a semiconductor device prepared as described above is applied to the substrate (exposed portions of the insulator layer, the source electrode, and the drain electrode). Coating methods include casting, spin coating, dip coating, blade coating, wire bar coating, spray coating and other coating methods, inkjet printing, screen printing, offset printing, letterpress printing, gravure printing, and other micro contact methods. A soft lithography technique such as a printing method, or a combination of these techniques may be employed. Furthermore, as a method similar to the coating method, the Langmuir project method in which a monomolecular film of a semiconductor layer produced by dropping the above-described ink on the water surface is transferred to a substrate and laminated, and two substrates of liquid crystal or melted material are used. It is also possible to adopt a method of sandwiching between the substrates or introducing between the substrates by capillary action. The film thickness of the organic semiconductor layer produced by this method is preferably thinner as long as the function is not impaired. There is a concern that the leakage current increases as the film thickness increases. The film thickness of the organic semiconductor layer is usually 0.1 nm to 10 μm, preferably 0.5 nm to 5 μm, more preferably 1 nm to 3 μm.

The semiconductor layer thus manufactured (see FIG. 2 (5)) can be further improved in characteristics by post-processing. For example, it is considered that the heat treatment reduces strain in the film generated during film formation, reduces pinholes, etc., and can control the arrangement and orientation in the film. The characteristics can be improved and stabilized. In order to improve the characteristics, it is effective to perform this heat treatment when producing the field effect transistor of the present invention. This heat treatment is performed by heating the substrate after forming the semiconductor layer. The temperature of the heat treatment is not particularly limited, but is usually about room temperature to 150 ° C, preferably 40 ° C to 120 ° C, more preferably 45 ° C to 100 ° C. The time at this time is not particularly limited, but is usually from 1 minute to 24 hours, preferably from about 2 minutes to 3 hours. The atmosphere at that time may be air, but may be an inert atmosphere such as nitrogen or argon.
The heat treatment may be performed at any stage as long as the semiconductor layer is formed, but it is more preferable to perform the heat treatment after forming the electrode in addition to the semiconductor layer than before forming the electrode.
As another post-treatment method for the semiconductor layer, a property change due to oxidation or reduction may be induced by treatment with an oxidizing or reducing gas such as oxygen or hydrogen or an oxidizing or reducing liquid. it can. This is used, for example, for the purpose of increasing or decreasing the carrier density in the film.

In addition, in a technique called doping, semiconductor layer characteristics can be changed by adding a trace amount of elements, atomic groups, molecules, and polymers to the semiconductor layer. For example, oxygen and hydrogen, acids such as hydrochloric acid, sulfuric acid, and sulfonic acid, Lewis acids such as PF ₅ , AsF ₅ , and FeCl ₃ , halogen atoms such as iodine, metal atoms such as sodium and potassium, and the like can be doped. . This can be achieved by bringing these gases into contact with the semiconductor layer, immersing them in a solution, or performing an electrochemical doping process. These dopings may be added during the synthesis of the semiconductor material, even after the semiconductor layer is not formed, or may be added to the ink in the process of manufacturing the semiconductor layer using the ink for manufacturing the semiconductor device. It can be added in the process step of forming the precursor thin film disclosed in Document 2. In addition, a material used for doping is added to the material for forming the semiconductor layer during vapor deposition, and co-evaporation is performed, or the semiconductor layer is mixed with the surrounding atmosphere when the semiconductor layer is formed (in the environment where the doping material exists) It is also possible to perform doping by accelerating ions in a vacuum and colliding with the film.

  These doping effects include changes in electrical conductivity due to increase or decrease in carrier density, changes in carrier polarity (p-type and n-type), changes in Fermi level, and the like. Such doping is often used particularly in semiconductor elements using inorganic materials such as silicon.

(Protective layer)
Forming the protective layer 7 on the semiconductor layer has an advantage that the influence of outside air can be minimized and the electrical characteristics of the organic field effect transistor can be stabilized (see FIG. 2 (6)). The above-mentioned materials are used as the protective layer material.
Although the film thickness of the protective layer 7 can employ | adopt arbitrary film thickness according to the objective, it is 100 nm-1 mm normally.
Various methods can be employed to form the protective layer. When the protective layer is made of a resin, for example, a solution containing a resin is applied and then dried to form a resin film, or a resin monomer is applied. Or the method of superposing | polymerizing after vapor deposition is mentioned. Cross-linking treatment may be performed after film formation. When the protective layer is made of an inorganic material, for example, a formation method in a vacuum process such as a sputtering method or a vapor deposition method, or a formation method in a solution process such as a sol-gel method can be used.
In the field effect transistor of the present invention, a protective layer can be provided between the layers as needed in addition to the semiconductor layer. These layers may help to stabilize the electrical properties of the organic field effect transistor.

  Since an organic material is used as a semiconductor material, the present invention can be manufactured by a relatively low temperature process. Accordingly, flexible materials such as plastic plates and plastic films that could not be used under conditions exposed to high temperatures can be used as the substrate. As a result, it is possible to manufacture a light, flexible, and hard-to-break element, which can be used as a switching element for an active matrix of a display. Examples of the display include a liquid crystal display, a polymer dispersion type liquid crystal display, an electrophoretic display, an EL display, an electrochromic display, a particle rotation type display, and the like. Furthermore, since the field effect transistor of the present invention can be manufactured by a solution process such as coating, it is possible to manufacture a large-area display compared to materials that could not be manufactured without using a vacuum process such as conventional vapor deposition. Therefore, a field effect transistor can be obtained at a very low cost as compared with the conventional one.

  The field effect transistor of the present invention can also be used as digital elements and analog elements such as memory circuit elements, signal driver circuit elements, and signal processing circuit elements. Further, by combining these, it is possible to produce an IC card or an IC tag. Furthermore, since the field effect transistor of the present invention can change its characteristics by an external stimulus such as a chemical substance, it can be used as an FET sensor.

  The operating characteristics of the field effect transistor are determined by the carrier mobility of the semiconductor layer, the conductivity, the capacitance of the insulating layer, the element configuration (distance and width between source and drain electrodes, film thickness of the insulating layer, etc.), and the like. Of the semiconductor materials used for the field effect transistor, the higher the carrier mobility, the more preferable as the material for the semiconductor layer. The compounds of the above formulas (1) to (3), particularly the compound of the above formula (1), have good film formability when used as a semiconductor layer material, and are applicable to a large area. The compound can be produced at a low cost. Further, pentacene derivatives and the like are unstable and difficult to handle compounds such as decomposition in the atmosphere due to moisture contained in the atmosphere, but the compounds represented by the above formulas (1) to (3) of the present invention. Is used as a material for the semiconductor layer, there is an advantage that it is stable and has a long life even after the semiconductor layer is manufactured.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated still in detail, this invention is not limited to these examples. In the examples, unless otherwise specified, parts represent parts by mass, and% represents mass%. The symbol Ar represents argon.
The various compounds obtained in the synthesis examples are ¹ H-NMR, ¹³ C-NMR (NMR is a nuclear magnetic resonance spectrum), MS (mass spectrometry spectrum), mp (melting point), and elemental analysis as necessary. The structural formula was determined by performing various measurements. The measuring equipment is as follows.
NMR: JEOL Lambda 400 spectrometer
MS: Shimadzu QP-5050A
Elemental analysis: Parkin Elmer2400 CHN type elemental analyzer

Synthesis example 1
Synthesis of 1,4-Dibromo-2,5-diodobenzene (5)

1,4-Dibromobenzene (4) (34.8 g, 148 mmol) and iodine (144 g, 583 mmol) were added to a 98% concentrated sulfuric acid solution (480 ml), and the mixture was heated at 125 to 135 ° C. for 6 hours. It was washed in turn with an aqueous sodium hydrogen sulfite solution, saturated aqueous sodium hydrogen carbonate solution and water and dried overnight. Recrystallization from benzene gave colorless needle crystals. (53g, 74%)
¹ H-NMR (60 MHz, CDCl ₃ ) δ 7.97 (s, 2H, 3, 6 positions)
m. p. 158-165 ° C

Synthesis example 2
Synthesis of 1,4-Dibromo-2,5-bis (trimethylsilylethyl) benzene (6)

In a nitrogen atmosphere, the above formula (5) (10 g, 21 mmol) was dissolved in anhydrous diisopropylamine (30 mL) and anhydrous benzene (120 mL), and then degassed for 30 minutes. Pd (PPh ₃ ) ₄ (0.7 g, 610 μmol), CuI (0.2 g, 1.1 mmol), TMSA (5.8 mL, 41 mmol) were added at room temperature, and the mixture was stirred at room temperature for 5 hours. After completion of the stirring, the reaction was terminated with water (300 ml), extracted with chloroform (50 mL × 3), washed with water (200 mL × 3), and dried over anhydrous magnesium sulfate. Chloroform was distilled off under reduced pressure and purified by column chromatography (silica gel, hexane, batch, Rf = 0.6). Recrystallization from hexane gave colorless needle crystals. (6.40 g, 73%)
¹ H-NMR (60 MHz, CDCl ₃ ) δ 7.59 (s, 2H, 3, 6 positions) 0.26 (s, 18H, TMS)
m. p. 127-132

Synthesis example 3
2.6 Synthesis of Dimethylmethylsilylbenzo [1,2-b: 4,5-b ′] dithiophene (7)

Under a nitrogen atmosphere, the above formula (6) (2.0 g, 4.7 mmol) was dissolved in anhydrous ether (40 mL), then cooled to −78 ° C., and a 1.59 M t-butyllithium / pentane solution (12.8 mL, 20 .4 mmol) was added, stirred at that temperature for 1 hour, heated to −30 ° C., sulfur powder (0.370 g, 11.5 mmol) was added, and the temperature was raised to room temperature. After treating with absolute ethanol (20 mL), the mixture was stirred for 3 hours, extracted with chloroform (30 mL × 3), washed with water (200 mL × 3), dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. Purification by column chromatography (silica gel, hexane: methylene chloride = 3: 1, batch, Rf = 0.8). Recrystallization from hexane gave yellow needle crystals. (1.1g, 67%)
¹ H-NMR (60 MHz, CDCl ₃ ) δ 8.19 (s, 2H, positions 4, 8) 7.39 (s, 2H, positions 3, 7) 0.39 (s, 18H, TMS)
m. p. 195-200 ° C

Synthesis example 4
Synthesis of 2,6-Diiobenzo [1,2-b: 4,5-b ′] dithiophene (8)

Under a nitrogen atmosphere, the above formula (7) (4 g, 12 mmol) was dissolved in anhydrous methylene chloride (120 mL), and 1M iodine monochloride / methylene chloride solution (28.8 mL) was added dropwise at −15 ° C. It stirred for 12 hours after completion | finish of dripping. Thereafter, the precipitated solid was collected by filtration and washed with ethanol (100 mL). Recrystallization from chlorobenzene gave colorless plate crystals. (3.8g, 71%)
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.09 (s, 2H, 4, 8 positions) 7.55 (s, 2H, 4, 8 positions)
M.M. S. (70 eV, EI) m / z 442 (M ⁺ )
m. p. > 300 ° C

Synthesis example 5
Synthesis of 2,6-Bis (Octyn-1-yl) benzo [1,2-b: 4,5-b ′] dithiophene (Compound No. 88)

Under a nitrogen atmosphere, the above formula (8) (1 g, 2.26 mmol) was dissolved in anhydrous diisopropylamine (15 mL) and anhydrous benzene (15 mL), and then deaerated by Ar bubbling for 30 minutes. PdCl ₂ (PPh ₃ ) ₂ (159 mg, 227 μmol), CuI (86 mg, 450 μmol) and 1-octyne (0.73 ml, 5.0 mmol) were added at room temperature, and the mixture was stirred at room temperature for 5 hours. After completion of the stirring, the reaction was terminated with water (60 mL), extracted with chloroform (10 mL × 3), washed with water (100 mL × 3) and then dried over anhydrous magnesium sulfate. Chloroform was distilled off under reduced pressure and purified by column chromatography (silica gel, hexane: methylene chloride = 3: 1, batch, origin). Recrystallization from hexane gave colorless plate crystals. (775 mg, 85%)
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.05 (s, 2H) 7.33 (s, 2H) 2.47 (t, J = 7.2 Hz, 4H) 1.65 to 1.24 (m, 16H) 0.88 (t, J = 6.4 Hz, 6H)
MS (70 eV, EI) m / z = 406 (M ⁺ )
m. p. 137.5-138.5 ° C
Anal. _{Calcd for C 26 H 30 S 2} : C, 76.79; H, 7.44
Found: C, 76.95; H, 7.51

Synthesis Example 6
Synthesis of 2,6-Dioctylbenzo [1,2-b: 4,5-b ′] dithiophene (Compound No. 16)

After Ar substitution, the above formula (Compound No. 88) (300 mg, 0.75 mmol) and Pd / C (100 mg) were added to anhydrous toluene (15 mL). After performing hydrogen gas replacement three times, the mixture was stirred for 3 days in a room temperature hydrogen gas atmosphere. The reaction solution was filtered to remove Pd / C, and the solvent of the filtrate was distilled off under reduced pressure, followed by purification by column chromatography (silica gel, hexane, batch, origin). Recrystallization from hexane gave colorless plate crystals. (285 mg, 91%)
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.01 (s, 2H) 6.98 (s, 2H) 2.89 (t, J = 7.2 Hz, 4H) 1.77-1.27 (m, 24H) 0.88 (t, J = 6.4 Hz, 6H)
¹³ C-NMR (100 MHz, CDCl ₃ ) δ 14.267, 22.2.83, 29.322, 29.388, 29.512, 31.106, 31.231, 32.008, 115.565, 119.543 136.715, 137.429, 146.800
MS (70 eV, EI) m / z = 414 (M ^<+> )
m. p. 133.5-134.5 ° C
Anal. _{Calcd for C 26 H 38 S 2} : C, 75.30; H, 9.24
Found: C, 75.07; H, 9.21

Synthesis example 7
Synthesis of 2,6-Bis (Dodecyn-1-yl) benzo [1,2-b: 4,5-b ′] dithiophene (Compound No. 91)

Under a nitrogen atmosphere, the above formula (8) (1 g, 2.26 mmol) was dissolved in anhydrous diisopropylamine (15 mL) and anhydrous benzene (15 mL), and then deaerated by Ar bubbling for 30 minutes. PdCl ₂ (PPh ₃ ) ₂ (159 mg, 227 μmol), CuI (86 mg, 450 μmol), 1-dodecine (1.1 ml, 5.0 mmol) were added at room temperature, and the mixture was stirred at room temperature for 5 hours. After completion of the stirring, the reaction was terminated with water (60 mL), extracted with chloroform (10 mL × 3), washed with water (100 mL × 3) and then dried over anhydrous magnesium sulfate. Chloroform was distilled off under reduced pressure and purified by column chromatography (silica gel, hexane: methylene chloride = 3: 1, batch, origin). Recrystallization from hexane gave colorless plate crystals. (1.04g, 89%)
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.04 (s, 2H) 7.33 (s, 2H) 2.47 (t, J = 7.2 Hz, 4H) 1.67-1.23 (m, 32H) 0.88 (t, J = 6.4 Hz, 6H)
MS (70 eV, EI) m / z = 518 (M ⁺ )
m. p. 114.5-115.5 ° C
Anal. _{Calcd for C 34 H 46 S 2} : C, 78.70; H, 8.94
Found: C, 78.96; H, 8.99

Synthesis Example 8
Synthesis of 2,6-Didodecylbenzo [1,2-b: 4,5-b ′] dithiophene (Compound No. 20)

After Ar substitution, the above formula (Compound No. 91) (400 mg, 0.77 mmol) and Pd / C (100 mg) were added to anhydrous toluene (20 mL). After performing hydrogen gas replacement three times, the mixture was stirred for 3 days in a room temperature hydrogen gas atmosphere. The reaction solution was filtered to remove Pd / C, and the solvent of the filtrate was distilled off under reduced pressure. Then, recrystallization from hexane gave colorless plate crystals. (365 mg, 90%)
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.01 (s, 2H) 6.98 (s, 2H) 2.89 (t, J = 7.2 Hz, 4H) 1.75-1.22 (m, 40H) 0.88 (t, J = 6.4 Hz, 6H)
MS (70 eV, EI) m / z = 526 (M ⁺ )
m. p. 127.5-128.5 ° C
Anal. _{Calcd for C 34 H 54 S 2} : C, 77.50; H, 10.33
Found: C, 77.35; H, 10.37

Synthesis Example 9
Synthesis of 2,6-bis (octyn-1-yl) benzo [1,2-b: 4.5-b ′] diselenophene (Compound No. 95)

Under a nitrogen atmosphere, 2,6-diodo [1,2-b: 4,5-b ′] diselenophene (in the above formula (208), X ¹ = X ² = Se) (0.25 g, 0.5 mmol) After dissolving in anhydrous diisopropylamine (5 mL) and anhydrous benzene (5 mL), degassing was performed by Ar bubbling for 30 minutes. PdCl ₂ (PPh ₃ ) ₂ (35 mg, 0.05 mol), CuI (19 mg, 0.1 mmol) and 1-octyn (0.15 ml, 1.0 mmol) were added at room temperature, and the mixture was stirred at room temperature for 20 hours. After completion of the stirring, the reaction was terminated with water (50 mL), extracted with chloroform (50 mL × 3), washed with water (150 mL × 3), and then dried over anhydrous magnesium sulfate. Chloroform was distilled off under reduced pressure and purified by column chromatography (silica gel, hexane, Rf = 0.3) to obtain a colorless solid (Compound No. 95). (169 mg, 72%)
m. p. 151.3-151.8 ° C
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.08 (s, 2H, ArH) 7.49 (s, 2H, ArH) 2.47 (t, J = 7.2 Hz, 4H, CH ₂ ) _{1.64~1.32 (m, 16H, CH 2} ) 0.91 (t, J = 7.0 Hz, 6H, CH 3)
EIMS (70 eV) m / z = 502 (M ⁺ )
IR (KBr) ν 869 cm ⁻¹ , 2215 cm ⁻¹ (C≡C), 2856 to 2951 cm ⁻¹ (C—H)
Anal. _{Calcd for C 26 H 30 Se 2} : C, 62.40; H, 6.04% Found C, 62.39; H, 6.03%

Synthesis Example 10
Synthesis of 2,6-dioctylbenzo [1,2-b: 4,5-b ′] diselenophene (Compound No. 47)

After Ar substitution, the above formula (Compound No. 95) (100 mg, 0.20 mmol) and Pd / C (35 mg) were dissolved in anhydrous toluene (5 mL). After performing hydrogen gas substitution 3 times, it stirred for 20 hours under normal temperature hydrogen gas atmosphere. The reaction solution was filtered to remove Pd / C, and the solvent of the filtrate was distilled off under reduced pressure. The residue was purified by column chromatography (silica gel, hexane, Rf = 0.3) to obtain a colorless solid. (82 mg, 81%).
m. p. 143.0-143.8 ° C
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.05 (s, 2H, ArH) 7.13 (s, 2H, ArH) 2.93 (t, J = 7.2 Hz, 4H, CH ₂ ) 1.73 (quant, J = 7.2 Hz, 4H, CH ₂ ) 1.40 to 1.27 (m, 20H, CH ₂ ) 0.88 (t, J = 7.0 Hz, 6H, CH ₃ )
¹³ C-NMR (100 MHz, CDCl ₃ ) δ 150.63 139.51 137.21 123.01 120.69 33.45 31.83 31.77 29.35 29.21 29.10 22.65 14. 11
EIMS (70 eV) m / z = 510 (M ⁺ )
Anal. _{Calcd for C 26 H 38 Se 2} : C, 61.41; H, 7.53% Found C, 61.56; H, 7.53%

Synthesis Example 11
Synthesis of 2,6-bis (decyn-1-yl) benzo [1,2-b: 4.5-b ′] diselenophene (Compound No. 96)

Under a nitrogen atmosphere, 2,6-diodo [1,2-b: 4,5-b ′] diselenophene (in the above formula (208), X ¹ = X ² = Se) (0.25 g, 0.5 mmol) After dissolving in anhydrous diisopropylamine (5 mL) and anhydrous benzene (5 mL), degassing was performed by Ar bubbling for 30 minutes. PdCl ₂ (PPh ₃ ) ₂ (35 mg, 0.05 mol), CuI (19 mg, 0.1 mmol) and 1-decyne (0.19 ml, 1.0 mmol) were added at room temperature, and the mixture was stirred at room temperature for 20 hours. After completion of stirring, the reaction was terminated with water (50 mL), extracted with chloroform (50 mL × 3), washed with water (150 mL × 3), and then dried over anhydrous magnesium sulfate. Chloroform was distilled off under reduced pressure and purified by column chromatography (silica gel, hexane, Rf = 0.3) to obtain a colorless solid (Compound No. 96). (220 mg, 84%)
m. p. 136.2-137.0 ° C
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.08 (s, 2H, ArH) 7.49 (s, 2H, ArH) 2.47 (t, J = 7.2 Hz, 4H, CH ₂ ) _{1.65~1.28 (m, 24H, CH 2} ) 0.89 (t, J = 7.0 Hz, 6H, CH 3)
¹³ C-NMR (68 MHz, CDCl ₃ ) δ 140.22 138.70 130.62 125.98 121.57 99.50 76.45 31.90 29.24 29.04 28.53 22.72 20. 05 14.15
EIMS (70 eV) m / z = 558 (M ⁺ )
IR (KBr) ν 871 cm ⁻¹ , 2215 cm ⁻¹ (C≡C), 2851 to 2952 cm ⁻¹ (C—H)
Anal. _{Calcd for C 30 H 38 Se 2} : C, 64.74; H, 6.88% Found C, 64.71; H, 6.92%

Synthesis Example 12
Synthesis of 2,6-dideylbenzo [1,2-b: 4,5-b ′] diselenophene (Compound No. 49)

After Ar substitution, the above formula (Compound No. 96) (100 mg, 0.18 mmol) and Pd / C (35 mg) were dissolved in anhydrous toluene (5 mL). After performing hydrogen gas substitution 3 times, it stirred for 20 hours under normal temperature hydrogen gas atmosphere. The reaction solution was filtered to remove Pd / C, and the solvent of the filtrate was distilled off under reduced pressure. The residue was purified by column chromatography (silica gel, hexane, Rf = 0.3) to obtain a colorless solid. (88 mg, 87%).
m. p. 133.8-135.0 ° C
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.05 (s, 2H, ArH) 7.13 (s, 2H, ArH) 2.93 (t, J = 7.2 Hz, 4H, CH ₂ ) 1.73 (quant, J = 7.2 Hz, 4H, CH ₂ ) 1.40 to 1.27 (m, 28H, CH ₂ ) 0.88 (t, J = 7.0 Hz, 6H, CH ₃ )
¹³ C-NMR (100 MHz, CDCl ₃ ) δ 150.99 139.87 133.56 123.37 121.05 33.82 32.25 32.13 29.94 29.90 29.75 29.68 29. 46 23.04 14.48
EIMS (70 eV) m / z = 566 (M ⁺ )
Anal. _{Calcd for C 30 H 46 Se 2} : C, 63.82; H, 8.21% Found C, 63.73; H, 8.08%

Synthesis Example 13
Synthesis of 2,6-bis (dodecyn-1-yl) benzo [1,2-b: 4.5-b ′] diselenophene (Compound No. 97)

Under a nitrogen atmosphere, 2,6-diodo [1,2-b: 4,5-b ′] diselenophene (in the above formula (208), X ¹ = X ² = Se) (0.25 g, 0.5 mmol) After dissolving in anhydrous diisopropylamine (5 mL) and anhydrous benzene (5 mL), degassing was performed by Ar bubbling for 30 minutes. PdCl ₂ (PPh ₃ ) ₂ (35 mg, 0.05 mol), CuI (19 mg, 0.1 mmol), 1-dodecine (0.22 ml, 1.0 mmol) were added at room temperature, and the mixture was stirred at room temperature for 20 hours. After completion of the stirring, the reaction was terminated with water (50 mL), extracted with chloroform (50 mL × 3), washed with water (150 mL × 3), and then dried over anhydrous magnesium sulfate. Chloroform was distilled off under reduced pressure and purified by column chromatography (silica gel, hexane, Rf = 0.3) to obtain a colorless solid (Compound No. 97). (245 mg, 85%)
m. p. 128.0-129.0C
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.08 (s, 2H, ArH) 7.49 (s, 2H, ArH) 2.47 (t, J = 7.2 Hz, 4H, CH ₂ ) 1.63-1.28 (m, 32 H, CH ₂ ) 0.88 (t, J = 7.0 Hz, 6 H, CH ₃ )
¹³ C-NMR (68 MHz, CDCl ₃ ) δ 140.07 138.56 130.49 125.86 121.46 99.43 76.45 32.06 29.73 29.66 29.48 29.29 29. 14 28.63 22.84 20.16 14.27
EIMS (70 eV) m / z = 612 (M ⁺ )
IR (KBr) ν 871 cm ⁻¹ , 2214 cm ⁻¹ (C≡C), 2850 to 2953 cm ⁻¹ (C—H)
Anal. _{Calcd for C 34 H 46 Se 2} : C, 66.66 H, 7.57% Found C, 66.84; H, 7.65%

Synthesis Example 14
Synthesis of 2,6-didedecylbenzo [1,2-b: 4,5-b ′] diselenophene (Compound No. 51)

After Ar substitution, the above formula (Compound No. 97) (100 mg, 0.16 mmol) and Pd / C (35 mg) were dissolved in anhydrous toluene (5 mL). After performing hydrogen gas substitution 3 times, it stirred for 20 hours under normal temperature hydrogen gas atmosphere. The reaction solution was filtered to remove Pd / C, and the solvent of the filtrate was distilled off under reduced pressure. The residue was purified by column chromatography (silica gel, hexane, Rf = 0.3) to obtain a colorless solid. (84 mg, 83%).
m. p. 127.0-128.5 ° C
¹ H-NMR (400 MHz, CDCl ₃ ) δ 8.05 (s, 2H, ArH) 7.13 (s, 2H, ArH) 2.93 (t, J = 7.2 Hz, 4H, CH ₂ ) _{1.73 (quint, J = 7.2 Hz} , 4H, CH 2) 1.42~1.26 (m, 36H, CH 2) 0.88 (t, J = 7.0 Hz, 6H, CH 3 )
¹³ C-NMR (100 MHz, CDCl ₃ ) δ 151.02 139.88 137.58 123.38 121.03 33.82 32.27 32.14 29.99 29.90 29.72 29.72 29. 45 23.05 14.50
EIMS (70 eV) m / z = 620 (M ⁺ )
Anal. _{Calcd for C 34 H 54 Se 2} : C, 65.79 H, 8.77% Found C, 65.58; H, 8.55%

Example 1
Compound No. obtained in Synthesis Example 5 above. 88 compounds were dissolved in chloroform to a concentration of 0.6% to prepare an ink for producing a semiconductor device.
The obtained ink was applied on an n-doped silicon wafer (surface resistance 0.02 Ω · cm or less) with a 200 nm SiO ₂ thermal oxide film subjected to OTS (octadecyltrichlorosilane) treatment, and spin coating (4000 rpm, 25 seconds). ) Was used to form a semiconductor thin film (layer), and this thin film was further heat-treated at 80 ° C. for 30 minutes under argon.
Next, this substrate is placed in a vacuum vapor deposition apparatus, evacuated until the degree of vacuum in the apparatus becomes 1.0 × 10 ⁻³ Pa or less, and gold electrodes (source and drain electrodes, channel length are formed by resistance heating vapor deposition). 50 μm, channel width 1500 μm) was deposited to a thickness of 80 nm to obtain a field effect transistor of the present invention. In the field effect transistor in this example, the thermal oxide film in the n-doped silicon wafer with the thermal oxide film has the function of the insulating layer (4), and the n-doped silicon wafer is the substrate (6) and the gate layer (5). It has a function (see FIG. 3).

The obtained field effect transistor was installed in a prober, and semiconductor characteristics were measured in the air using a semiconductor parameter analyzer. For semiconductor characteristics, the gate voltage was scanned from 20 V to -100 V in 20 V steps, the drain voltage was scanned from 10 V to -100 V, and the drain current-drain voltage was measured. As a result, current saturation was observed, and the obtained device showed a p-type semiconductor from the obtained voltage-current curve. The carrier mobility was 3 × 10 ⁻⁴ cm ² / Vs. The on / off ratio was 1 × 10 ² and the threshold voltage was −30V.

Example 2
Compound No. 12 was dissolved in chloroform to a concentration of 0.4% to prepare an ink for producing a semiconductor device.
The obtained ink was applied onto an n-doped silicon wafer with 200 nm SiO ₂ thermal oxide film (surface resistance 0.02 Ω · cm or less), and a semiconductor thin film (layer) was formed using a spin coating method (4000 rpm, 25 seconds). Then, this thin film was heat-treated at 110 ° C. for 30 minutes under argon. An electrode was formed on this substrate in the same manner as in Example 1 to obtain a field effect transistor of the present invention. Similarly, when the semiconductor characteristics were measured, the device showed a p-type semiconductor. The carrier mobility was 4 × 10 ⁻⁵ cm ² / Vs. The on / off ratio was 1 × 10 ⁴ and the threshold voltage was −30V.
In addition, Compound No. 12 can be synthesized according to the methods of Synthesis Examples 5 and 6 in the same manner except that 1-octyne used in Synthesis Example 5 is replaced with 1-hexyne. The obtained Compound No. The melting point of 12 was 144.5 to 145.5 ° C.

Example 3
Compound No. obtained in Synthesis Example 6 16 was dissolved in chloroform to a concentration of 0.4% to prepare an ink for preparing a semiconductor device.
The obtained ink was applied onto an n-doped silicon wafer with 200 nm SiO ₂ thermal oxide film (surface resistance 0.02 Ω · cm or less), and a semiconductor thin film (layer) was formed using a spin coating method (4000 rpm, 25 seconds). Then, this thin film was heat-treated at 100 ° C. for 30 minutes under argon. An electrode was formed on this substrate in the same manner as in Example 1 to obtain a field effect transistor of the present invention. Similarly, when the semiconductor characteristics were measured, the device showed a p-type semiconductor. The carrier mobility was 1 × 10 ⁻² cm ² / Vs. The on / off ratio was 1 × 10 ⁵ and the threshold voltage was −30V.

Example 4
Compound No. 18 was dissolved in chloroform to a concentration of 0.4% to prepare an ink for preparing a semiconductor device.
The obtained ink was applied onto an n-doped silicon wafer with 200 nm SiO ₂ thermal oxide film (surface resistance 0.02 Ω · cm or less), and a semiconductor thin film (layer) was formed using a spin coating method (4000 rpm, 25 seconds). Then, this thin film was heat-treated at 110 ° C. for 30 minutes under argon. An electrode was formed on this substrate in the same manner as in Example 1 to obtain a field effect transistor of the present invention. Similarly, when the semiconductor characteristics were measured, the device showed a p-type semiconductor. The carrier mobility was 2.5 × 10 ⁻² cm ² / Vs. The on / off ratio was 1 × 10 ⁷ and the threshold voltage was −20V.
In addition, Compound No. 18 can be synthesized according to the methods of Synthesis Examples 5 and 6 in the same manner except that 1-octyne of Synthesis Example 5 is replaced with 1-decyne. The obtained Compound No. The melting point of 18 was 121.2-122.1 ° C.

Example 5
Compound No. obtained in Synthesis Example 8 20 was dissolved in chloroform to a concentration of 0.4% to prepare an ink for preparing a semiconductor device.
The obtained ink was applied onto an n-doped silicon wafer with 200 nm SiO ₂ thermal oxide film (surface resistance 0.02 Ω · cm or less), and a semiconductor thin film (layer) was formed using a spin coating method (4000 rpm, 25 seconds). Then, this thin film was heat-treated at 100 ° C. for 30 minutes under argon. An electrode was formed on this substrate in the same manner as in Example 1 to obtain a field effect transistor of the present invention. Similarly, when the semiconductor characteristics were measured, the device showed a p-type semiconductor. The carrier mobility was 2.6 × 10 ⁻² cm ² / Vs. The on / off ratio was 1 × 10 ⁷ and the threshold voltage was −20V.

Example 6
Compound No. obtained in Synthesis Example 10 47 was dissolved in chloroform to a concentration of 0.8% to prepare an ink for preparing a semiconductor device.
The obtained ink was applied onto an n-doped silicon wafer (surface resistance 0.02 Ω · cm or less) with a 200 nm SiO ₂ thermal oxide film, and a semiconductor thin film (layer) was formed using a spin coating method (3000 rpm, 25 seconds). Then, this thin film was heat-treated at 80 ° C. for 30 minutes under argon. An electrode was formed on this substrate in the same manner as in Example 1 to obtain a field effect transistor of the present invention. Similarly, when the semiconductor characteristics were measured, the device showed a p-type semiconductor. The carrier mobility was 0.03 cm ² / Vs. The on / off ratio was 1 × 10 ⁶ and the threshold voltage was −25V.

Example 7
Compound No. obtained in Synthesis Example 12 49 was dissolved in chloroform to a concentration of 1.0% to prepare an ink for producing a semiconductor device.
The obtained ink was applied onto an n-doped silicon wafer (surface resistance 0.02 Ω · cm or less) with a 200 nm SiO ₂ thermal oxide film, and a semiconductor thin film (layer) was formed using a spin coating method (3000 rpm, 25 seconds). Then, this thin film was heat-treated at 80 ° C. for 30 minutes under argon. An electrode was formed on this substrate in the same manner as in Example 1 to obtain a field effect transistor of the present invention. Similarly, when the semiconductor characteristics were measured, the device showed a p-type semiconductor. The carrier mobility was 0.01 cm ² / Vs. The on / off ratio was 1 × 10 ⁵ and the threshold voltage was −15V.

Example 8
Compound No. obtained in Synthesis Example 14 51 was dissolved in chloroform to a concentration of 1.2% to prepare an ink for preparing a semiconductor device.
The obtained ink was applied onto an n-doped silicon wafer (surface resistance 0.02 Ω · cm or less) with a 200 nm SiO ₂ thermal oxide film, and a semiconductor thin film (layer) was formed using a spin coating method (3000 rpm, 25 seconds). Then, this thin film was heat-treated at 100 ° C. for 30 minutes under argon. An electrode was formed on this substrate in the same manner as in Example 1 to obtain a field effect transistor of the present invention. Similarly, when the semiconductor characteristics were measured, the device showed a p-type semiconductor. The carrier mobility was 0.03 cm ² / Vs. The on / off ratio was 1 × 10 ⁶ and the threshold voltage was −20V.

  From the semiconductor characteristics described in each example, the field effect transistor of the present invention operates stably in the atmosphere, has high semiconductor characteristics, and does not use a vapor deposition method that requires special equipment, such as spin coating. It was confirmed that it can be easily and inexpensively produced by a coating method or the like. Therefore, the field effect transistor of the present invention is extremely useful.

It is the schematic which shows the structural example of the field effect transistor of this invention. It is the schematic of the process for manufacturing the example of 1 aspect of the field effect transistor of this invention. 1 is a schematic view of a field effect transistor of the present invention obtained in Example 1. FIG.

Explanation of symbols

The same number is attached | subjected to the same name in FIGS. 1-3.
1 source electrode 2 semiconductor layer 3 drain electrode 4 insulator layer 5 gate electrode 6 substrate 7 protective layer

Claims (12)

A field effect transistor comprising a compound represented by the following formula (1) as a semiconductor material.

(In ^the formula (1), ^{X 1} and ^{X 2} are identical and represent an unsubstituted or substituted C4-C20 aliphatic hydrocarbon group, respectively .R ¹ and ^{R 2} are independently represents a sulfur atom or selenium atom .) The field effect transistor according to claim 1, wherein both X ¹ and X ² in formula (1) are sulfur atoms. The field effect transistor according to claim 1 or 2 , wherein R ¹ and R ² in formula (1) are each independently an unsubstituted aliphatic hydrocarbon group. The field effect transistor according to claim 3 , wherein R ¹ and R ² in formula (1) are each independently a saturated aliphatic hydrocarbon group. The field effect transistor according to claim 4 , wherein R ¹ and R ² in formula (1) are each independently a linear aliphatic hydrocarbon group. An ink for producing a semiconductor device comprising the compound of formula (1) according to claim 1 . A method for producing a field effect transistor, wherein the semiconductor layer is formed by applying the ink for producing a semiconductor device according to claim 6 on a substrate and drying it. 8. The method of manufacturing a field effect transistor according to claim 7 , wherein the semiconductor layer is formed in the atmosphere. 9. The method of manufacturing a field effect transistor according to claim 7 , wherein heat treatment is performed after the semiconductor layer is formed. The method of manufacturing a field effect transistor according to claim 9 , wherein the heat treatment temperature is 40-120 ° C. A compound represented by the following formula ( 1 ).

(In ^the formula (1), ^{X 1} and ^{X 2} are identical and represent an unsubstituted or substituted C4-C20 aliphatic hydrocarbon group each independently .R ¹ and ^{R 2} represents a sulfur atom or selenium atom. ) The compound of Claim 11 represented by following formula (3).

(Wherein (in 3), ^{R 5} and ^{R 6} each independently represent a C2-C 18 aliphatic hydrocarbon group, ^{X 1} and ^{X 2} are the same. Representing a sulfur atom or selenium atom)

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