JP2005328030A - Ink for producing semiconductor device and method for producing semiconductor device using the same - Google Patents

Abstract

An ink for manufacturing a semiconductor device capable of providing a semiconductor device having an organic semiconductor layer, and a semiconductor device having excellent semiconductor characteristics, in particular, a field effect transistor having an excellent threshold voltage and On / Off ratio, and the same A method for manufacturing a semiconductor device using the semiconductor device is provided.
A semiconductor device having a solution having a porphyrin compound concentration of 0.1% by weight or more as a basic component, a surface tension of 10 to 60 mN / m, a viscosity of 1 to 50 mPa · s, and a boiling point of 75 to 250 ° C. An ink for manufacturing and a method for manufacturing a semiconductor device in which a semiconductor layer is formed by applying the ink for manufacturing a semiconductor device onto a surface on which a semiconductor layer is to be formed and drying.
[Selection figure] None

Description

  The present invention relates to an ink for manufacturing a semiconductor device having an organic semiconductor layer, and a method for manufacturing a semiconductor device using the same.

  A semiconductor device having an organic semiconductor layer is capable of forming a layer by a formation method such as application of a solution or printing as compared to a conventional layer formation method such as vapor deposition using an inorganic semiconductor such as silicon. In addition to the advantages in terms of formation cost, it is attracting attention because it is possible to fabricate devices that are given weight reduction, impact resistance, etc. by using plastics.

As an organic semiconductor in a semiconductor device having such an organic semiconductor layer, for example, an aromatic condensed hydrocarbon such as pentacene, an oligothiophene having four or more thiophene rings connected, or a polymer compound such as polythiophene or polyfluorene However, it is known as an organic semiconductor that can be applied to, for example, a field effect transistor (see, for example, Non-Patent Document 1). Furthermore, while it is difficult for these organic compounds to form a layer by application of a solution or the like, a semiconductor layer can be easily formed by application of a solution or the like, and an organic semiconductor that can exhibit high mobility is polyphyllin. Compounds have been proposed (see, for example, Patent Document 1).
C. R. Kagan, P.A. Andry editing "Thin-Film Transistors" (Marcel Dekker, New York 2003) JP 2004-6750 A

  However, according to the study of the present inventor, in the method for forming a semiconductor layer using a porphyrin compound described in Patent Document 1, chloroform or chlorobenzene is used as a solvent for a coating solution (ink). Not only is the environment inferior, but peripheral devices such as coating devices are easily corroded, and the semiconductor characteristics as a semiconductor device are not sufficient. For example, as a field effect transistor, the absolute value of the threshold voltage deviates from 0 V, The problem that the On / Off ratio is small is inherent, and it has been found that there is room for improvement in these respects.

  The present invention has been made in view of the above-described prior art. Accordingly, the present invention relates to a semiconductor device having an organic semiconductor layer, which is excellent in semiconductor characteristics, in particular, a threshold voltage, and On / Off. An object of the present invention is to provide a semiconductor device manufacturing ink capable of providing a field effect transistor having an excellent ratio, and a method of manufacturing a semiconductor device using the same.

  As a result of intensive studies to solve the above problems, the present inventor has found that an ink having a specific surface tension, a specific viscosity, and a specific boiling point can achieve the object, and has reached the present invention. In the present invention, a solution in which the concentration of the porphyrin compound represented by the following general formula (Ia) or (Ib) is 0.1% by weight or more is a basic component, the surface tension is 10 to 60 mN / m, and the viscosity is 1 Semiconductor device-forming ink having a boiling point of 75 to 250 ° C. and a semiconductor that forms a semiconductor layer by applying and drying the semiconductor device-forming ink on the surface on which the semiconductor layer is formed The gist is a method for manufacturing a device.

[In formulas (Ia) and (Ib), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently have a hydrogen atom, a hydroxyl group, or a substituent. R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² each independently represents a hydrogen atom, a monovalent organic group, an amino group, a nitro group, a monovalent organic group, or a halogen atom, which may be Or, it represents a halogen atom, and M represents a metal atom. ]

  ADVANTAGE OF THE INVENTION According to this invention, in the semiconductor device which has an organic-semiconductor layer, the ink for semiconductor device preparation which can give the semiconductor device excellent in the semiconductor characteristic, especially the field effect transistor excellent in threshold voltage and On / Off ratio. And a method for manufacturing a semiconductor device using the same.

<Semiconductor device manufacturing ink>
1. Porphyrin Compound In the ink for producing a semiconductor device of the present invention, the porphyrin compound as the organic semiconductor is a compound represented by the general formula (Ia) or (Ib). In the general formulas (Ia) and (Ib), examples of the substituent of the amino group of R ^{1 to} R ⁸ include an alkyl group having 1 to 10 carbon atoms, and 1 to 1 of R ^{1 to} R ⁸ . The valent organic group is preferably one having 1 to 10 carbon atoms, specifically, for example, an alkyl group, an alkoxy group, an alkylthio group, an acyl group, a carboxyl group, and an alcohol having 1 to 10 carbon atoms. Ester group, formyl group, carbamoyl group and the like, and these organic groups may have a substituent. In addition, examples of the halogen atom represented by R ^{1 to} R ⁸ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Adjacent R ¹ and R ² , R ³ and R ⁴ , R ⁵ and R ⁶ , and R ⁷ and R ⁸ may be bonded to form a ring, in which case the ring formed Examples of the ring include aromatic rings such as a benzene ring, naphthalene ring and anthracene ring; heterocycles such as a pyridine ring, quinoline ring, furan ring and thiophene ring; and alicyclic rings such as a cyclohexene ring.

Examples of the monovalent organic group represented by R ^{9 to} R ¹² include an alkyl group, an alkoxy group, an alkylthio group, an ester group of a carboxyl group and an alcohol having 1 to 10 carbon atoms, an aryl group, and the like. The group may have a substituent. Examples of the halogen atom represented by R ^{9 to} R ¹² include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The metal atom of M is preferably copper, nickel, iron, zinc, aluminum, platinum, tin, magnesium, cobalt, titanium, or vanadium, and particularly preferably copper or zinc.

  Specific examples of the porphyrin compounds described above include those described in Patent Document 1. Among these, tetrabenzoporphyrins are particularly preferable as organic semiconductors capable of forming a semiconductor layer by a coating method, and metal-free tetrabenzoporphyrins and divalent metal complexes such as copper and zinc are particularly preferable.

  In addition, in the semiconductor device manufacturing ink of the present invention, when the organic semiconductor layer of the porphyrin compound is formed using the ink, in addition to a method of applying a solution (ink) in which the porphyrin compound itself is dissolved in a solvent. After preparing a precursor solution (ink) in which a precursor of a porphyrin compound is dissolved in a solvent and applying the precursor solution (ink), the chemical structure of the precursor is changed to obtain a final porphyrin compound. A method of forming a semiconductor layer can also be adopted. This method is particularly effective when forming an organic semiconductor layer of a porphyrin compound that is hardly soluble in a solvent.

  As the precursor when forming an organic semiconductor layer of a porphyrin compound using a precursor, that is, the porphyrin compound represented by the general formula (Ia) or (Ib) in the ink for producing a semiconductor device of the present invention. For example, a porphyrin compound having the following bicyclo structure is exemplified as a preferable compound because ethylene molecules are dissociated by heating to change into a benzene ring. The two bonds of the bicyclo structure below and the benzene ring in which the bicyclo structure is changed are bonds connected to porphyrin.

  In general, the formation of an organic semiconductor layer using a solution (ink), particularly when the organic semiconductor is a low molecular compound, the film forming property is not improved, and it is difficult to obtain an organic semiconductor layer with high crystallinity. However, according to the method using the precursor, an organic semiconductor layer having excellent characteristics with high crystallinity can be obtained using a solution. That is, since the bicyclo structure is three-dimensionally bulky, the crystallinity is low, and therefore the molecule having the bicyclo structure has good solubility, and when the solution is applied, the crystallinity is low or amorphous. A film is easily obtained. In addition, when the bicyclo structure is changed to a benzene ring through a heating step, a molecular structure with good planarity is obtained, so that crystallinity is improved. Therefore, by utilizing a chemical change from a precursor having a bicyclo structure, an organic semiconductor layer made of a porphyrin compound having good crystallinity can be obtained by coating or the like even with a porphyrin compound having low solubility in a solvent. . The heating for converting the precursor to the final porphyrin compound may also serve other purposes such as distilling off the coating solvent.

  As the porphyrin compound, a benzoporphyrin compound in which a benzene ring is condensed on a pyrrole ring can be obtained from a precursor having a bicyclo structure, so that an organic semiconductor layer is formed by coating or the like using the above method. It is advantageous to do.

2. Solvent In the ink for producing a semiconductor device of the present invention, the solvent of the solution is preferably any one selected from the group consisting of ketone solvents, ester solvents, and halogen-free aromatic solvents. Two or more of these may be used in combination.

  Here, specific examples of ketone solvents include methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, acetonyl acetone, mesi Examples include tiloxide, phorone, isophorone, cyclohexanone, cyclopentanone, methylcyclohexanone, acetophenone, and camphor. Among these, methyl ethyl ketone and cyclohexanone are more preferable.

  Specific examples of the ester solvent include propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isopentyl acetate, 3-methoxybutyl acetate, sec-hexyl acetate, and acetic acid. 2-ethylbutyl, 2-ethylhexyl acetate, cyclohexyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, isopentyl propionate, butyric acid ester, isobutyric acid ester, isovaleric acid ester, stearic acid ester, benzoic acid ester , Ethyl cinnamate, abietic acid ester, bis (2-ethylhexyl) adipate, γ-butyrolactone, oxalic acid ester, malonic acid ester, maleic acid ester, dibutyl tartrate, tributyl citrate, sebacic acid ester Phthalic acid ester, ethylene glycol monoacetate, ethylene diacetate, ethylene glycol ester, diethylene glycol monoacetate, monoacetin, diacetin, triacetin, monobutyrin, diethyl carbonate, propylene carbonate, borate ester, phosphate ester, etc. Among these, benzoic acid ester, ethylene glycol monoacetate, ethylene glycol ester, and diethylene glycol monoacetate are more preferable, benzoic acid ester is particularly preferable, and ethyl benzoate is most preferable.

  Non-halogen-containing aromatic solvents include benzene, toluene, xylene, ethylbenzene, cumene, mesitylene, p-cymene, cyclohexylbenzene, diethylbenzene, pentylbenzene, dipentylbenzene, dodecylbenzene, tetralin, anisole, phenetole, butylphenyl. Examples include ether, pentylphenyl ether, methoxytoluene, benzylethyl ether, methoxytoluene, aniline, veratrol, nitrobenzene, and among these, toluene, xylene, tetralin, and anisole are more preferable.

3. Other Components The ink for producing a semiconductor device of the present invention having a solution of the porphyrin compound as a basic component may further contain additive components such as a leveling agent and a thickener. However, if these components remain in the organic semiconductor layer after removal of the solvent, they may adversely affect the semiconductor characteristics as impurities, and therefore it is preferable that they have a low boiling point that is easily removed together with the removal of the solvent. .

4). Physical Properties of Semiconductor Device Preparation Ink The semiconductor device preparation ink of the present invention contains, as a basic component, a solution of the solvent in which the concentration of the porphyrin compound is 0.1% by weight or more. In this case, the concentration of the porphyrin compound is preferably 0.5 to 2% by weight.

  Further, the ink for producing a semiconductor device of the present invention must have a surface tension of 10 to 60 mN / m, preferably 12 to 55 mN / m, and particularly preferably 15 to 50 mN / m. . In order to sufficiently wet the semiconductor layer formation surface when forming a solution layer on the semiconductor layer formation surface by applying or printing ink, the surface of the semiconductor layer formation surface that is solid The surface tension of the ink needs to be smaller than the tension, and needs to be in the above range.

  The ink for producing a semiconductor device of the present invention must have a viscosity of 1.0 to 50 mPa · s, preferably 1.1 to 30 mPa · s, and 1.2 to 20 mPa · s. Particularly preferred. In order to sufficiently wet the surface where the semiconductor layer is formed as well as the surface tension, it is effective that the viscosity of the ink is small, but if the viscosity is too small, the pattern is formed when fine patterning that is essential for semiconductor devices is performed. This causes a problem that patterning cannot be performed. On the other hand, when the viscosity is too large, there is a problem that the nozzle head is clogged when an ink jet or the like is used.

  The ink for producing a semiconductor device of the present invention has a boiling point of 75 to 250 ° C., preferably 80 to 230 ° C., particularly preferably 100 to 200 ° C. When the boiling point is low, the porphyrin compound absorbs water with the volatilization of the solvent and contains crystal water, so that the semiconductor characteristics are deteriorated, for example, the absolute value of the threshold voltage is increased in a field effect transistor, while the boiling point is high. The removal of the solvent becomes incomplete, causing a problem such as a defect caused by the residual solvent as a semiconductor device.

5). Preparation of ink for semiconductor device preparation The ink for semiconductor device preparation of the present invention is prepared by dissolving the porphyrin compound in the solvent so that the concentration falls within the above range, and further adding an additive component as necessary. Is done. In this case, the melting temperature is preferably in the range of 10 to 140 ° C, particularly preferably in the range of 20 to 80 ° C. If the dissolution temperature is less than the above range, the solubility of the porphyrin compound is poor, and if it exceeds the above range, the porphyrin compound tends to be thermally decomposed. Moreover, it is preferable to filter the solution which melt | dissolved the porphyrin compound with a 0.1-100 micrometers filter, and to remove a solid substance.

<Semiconductor devices>
1. Formation of Semiconductor Layer In the present invention, in order to form a semiconductor layer on a semiconductor layer formation surface of a semiconductor device using the semiconductor device manufacturing ink, the ink is applied or printed on the semiconductor layer formation surface. After forming the ink layer, the ink layer can be dried. The method for forming the ink layer is not particularly limited. For example, coating methods such as casting, spin coating, dip coating, blade coating, wire bar coating, spray coating, ink jet printing, bubble jet (registered trademark) printing, Examples thereof include printing methods such as screen printing, offset printing and letterpress printing, and soft lithography methods such as microcontact printing. In addition, you may use these methods in combination of 2 or more types suitably. Furthermore, as a method similar to coating, a Langmuir-Blodgett method in which a monomolecular film of a semiconductor material formed on a water surface is transferred to a substrate and laminated, a liquid crystal or a melted semiconductor material is sandwiched between two substrates, or a capillary tube There is also a method of introducing between two substrates due to a phenomenon.

  Further, in the present invention, the processing using photolithography used in inorganic semiconductors or the like can be performed by ink jetting. At that time, the viscosity of the ink is 1.0 to 50 mPa · s as described above. By setting the range, it is possible to solve the problem that the discharge amount, the discharge direction, and the like vary depending on the temperature when the discharged ink droplet is separated from the ink in the nozzle and the viscosity of the ink, In a continuous ink jet in which each ink droplet is charged and landed at an arbitrary position, the flight time is controlled by adjusting the pressure according to the change in viscosity by the TOF control inside the print head. By controlling the viscosity change by making the boiling point of the range of 75 to 250 ° C., it is easy to control them.

  Furthermore, the ink for producing a semiconductor device of the present invention solves the ink accumulation at the edge of the printed image in screen printing by setting the surface tension in the range, the viscosity in the range, and the boiling point in the range. In addition, it is possible to form a layer by pad printing or the like having intermediate printability between direct printing and screen printing.

  In the present invention, when a semiconductor layer is formed using a precursor, the precursor and the organic semiconductor material can be obtained by repeating the formation process such as coating and printing of the precursor ink and the chemical structure changing process such as heating. The organic semiconductor layer can be laminated so as not to dissolve in the solvent of the precursor ink, and a thick film can be formed by utilizing the fact that the solubility is different from that of the organic semiconductor layer.

  In addition, as a method for controlling the crystal orientation of the semiconductor layer, an epitaxial growth method, a labinig after coating, or the like can be used. By these methods, it is possible to reduce the electrical resistivity of the channel.

The formed semiconductor layer may be so-called doped to contain a trace amount of an element, an impurity such as an atomic group, a molecule, or a polymer for the purpose of changing the characteristics of the semiconductor layer. As a doping method at that time, a known method can be arbitrarily used according to the characteristics of the semiconductor layer to be formed. Specific examples include oxygen, hydrogen, hydrochloric acid, sulfuric acid, sulfonic acid and other acids, PF ₆ , AsF ₅ , FeCl _{3 and} other Lewis acids, iodine and other halogen atoms, and sodium and potassium metal atoms and other dopants. Using, for example, mixing the dopant into organic semiconductor material or precursor ink, or contacting or immersing the dopant in gas or solution of the dopant at the stage of forming the precursor layer, and processing before forming the semiconductor layer A method and a method of processing after forming the semiconductor layer, such as contacting or immersing the formed semiconductor layer in a gas or solution of the dopant, or performing an electrochemical treatment, are employed. By these doping treatments, effects such as change in electrical conductivity due to increase or decrease in carrier density, change in carrier polarity (p-type or n-type), change in Fermi level, and the like can be obtained.

  In addition, the formed semiconductor layer is subjected to heat treatment, for example, to reduce distortion in the layer generated during layer formation, to improve and stabilize characteristics, and to oxidize or reduce oxygen, hydrogen, etc. By subjecting to a gas or a liquid, post-treatment such as inducing a characteristic change due to oxidation or reduction such as increase or decrease of carrier density in the layer can be performed.

  In the semiconductor device of the present invention, the semiconductor layer may be formed from a single layer or may be formed from two or more layers. Further, since the thickness of the semiconductor layer is likely to increase as the leakage current increases, the thickness of the semiconductor layer is preferably as thin as possible within a range in which a necessary function can be performed, and is preferably 10 μm or less, and more preferably 1 μm or less. , 500 nm or less is particularly preferable. Further, it is preferably 1 nm or more, more preferably 5 nm or more, and particularly preferably 10 nm or more.

2. Fabrication of Semiconductor Device In the present invention, the semiconductor device has the semiconductor layer and has two or more electrodes, and a current flowing between the electrodes or a generated voltage other than light, for example, electricity, magnetism, or A device controlled by chemical substances. For example, there are a device that controls current and voltage by applying voltage and current, a device that controls voltage and current by applying a magnetic field, and a device that controls voltage and current by applying a chemical substance. Examples of this control include rectification, switching, amplification, and oscillation. In addition, even in a device controlled by light or controlling light emission, the semiconductor material according to the present invention can be used for applications other than operating by directly absorbing light or emitting light, for example, control of wiring and the above voltage and current. This includes devices used for.

  Currently, the corresponding devices realized by inorganic semiconductors such as silicon include resistors, rectifiers (diodes), switching elements (transistors, thyristors), amplification elements (transistors), memory elements, chemical sensors, etc. Examples include combinations of elements and integrated devices. More specific examples of these include S.I. M.M. Examples include those described in Sze, Physics of Semiconductor Devices, 2nd Edition (Wiley-Interscience 1981).

  These semiconductor devices are usually fabricated on a substrate, and examples of the substrate include inorganic materials such as glass, silicon oxide, and metals such as silicon, and organic materials such as various organic polymers. Can be used in combination of two or more types including, for example, a combination of an inorganic material and an organic material such as a substrate in which an organic polymer is coated on the surface of an inorganic material substrate and an insulating layer is formed on the surface it can. Examples of the organic polymer include polyester, polycarbonate, polyimide, polyamide, polyether sulfone, epoxy resin, polybenzoxazole, polybenzothiazole, polyparabanic acid, polysilsesquioxane, polyvinylphenol, and polyolefin. Moreover, these organic polymers may contain a filler, an additive, etc. as needed.

  Further, the surface of these substrates may be subjected to a surface treatment for changing the characteristics of the layer formed thereon, for example, by adjusting the balance between hydrophilicity and hydrophobicity. For example, the characteristics of the semiconductor layer vary greatly depending on the state of molecular orientation and the like. Therefore, the molecular orientation at the interface between the substrate and the semiconductor layer is controlled by the surface treatment of the substrate, and the characteristics can be improved. Examples of such substrate surface treatment means include hydrophobization treatment with hexamethyldisilazane, cyclohexene, octadecyltrichlorosilane, etc., acid treatment with hydrochloric acid, sulfuric acid, acetic acid, etc., sodium hydroxide, potassium hydroxide, calcium hydroxide. , Alkaline treatment with ammonia, ozone treatment, fluorination treatment, plasma treatment with oxygen, argon, etc., formation treatment of Langmuir / Blodgett film, other thin film formation treatment such as insulators and semiconductors, corona discharge, etc. Processing, mechanical processing, and the like.

In addition, for electrodes and wires in semiconductor devices, for example, metals such as platinum, gold, aluminum, chromium, nickel, copper, titanium, magnesium, calcium, barium, and sodium, as well as conductive materials such as InO ₂ , SnO ₂ , ITO, etc. Conductive polymers such as conductive metal oxides, polyaniline, polypyrrole, polythiophene, polyacetylene, polydiacetylene, and acids such as hydrochloric acid, sulfuric acid, sulfonic acid, Lewis acids such as PF ₆ , AsF ₅ , FeCl ₃ , iodine, etc. Those added with dopants such as metal atoms such as halogen atoms, sodium and potassium, semiconductor materials such as silicon, germanium and gallium arsenide and those added with dopants, carbon materials such as fullerenes, carbon nanotubes and graphite, and Carbon black, graphite powder, metal It includes a composite material of the conductive dispersed particles or the like or the like.

  These electrodes and wirings are formed, for example, by patterning a film formed by a vacuum deposition method, a sputtering method, a coating method, a printing method, a sol-gel method or the like into a desired shape as necessary. . As the patterning method, for example, a photolithographic method combining photoresist patterning and etching such as wet etching with an etchant or dry etching with reactive plasma, ink jet printing, screen printing, offset printing, letterpress printing, etc. Soft lithography techniques such as the printing method and micro contact printing method, and a combination of these techniques. It is also possible to directly form a pattern by irradiating an energy beam such as a laser or an electron beam to remove the material or changing the conductivity of the material.

  In addition, the semiconductor device according to the present invention preferably has a protective film as the outermost layer in order to minimize the influence of outside air. Examples of the protective layer include polymer films such as epoxy resin, acrylic resin, polyurethane, polyimide, and polyvinyl alcohol, inorganic oxide films such as silicon oxide, aluminum oxide, and silicon nitride, and nitride films. The polymer film is formed by a method in which a solution is applied and dried, a method in which a monomer is applied or vapor-deposited and polymerized, and a crosslinking treatment or a multilayer film can also be formed. For the formation of the inorganic film, a formation method using a vacuum process such as a sputtering method or a vapor deposition method, or a formation method using a solution process typified by a sol-gel method can be used.

3. Specific example of semiconductor device 3-1. Field effect transistor (FET)
In the present invention, a field effect transistor (FET) can be mentioned as a suitable example of these semiconductor devices. A field effect transistor has a gate electrode and a semiconductor layer separated by a gate insulating layer on a substrate, and a source electrode and a drain electrode provided in contact with the semiconductor layer, and a voltage is applied to the gate electrode. Then, a current flow path (channel) is formed at the interface between the semiconductor layer and the adjacent layer between the source electrode and the drain electrode. With this configuration, the source electrode and the source electrode are separated by the input voltage applied from the gate electrode. This is a mechanism for controlling the current flowing between the drain electrode.

  The structure of the field effect transistor will be described with reference to the drawings. FIGS. 1A to 1D are longitudinal sectional views showing typical structures of the field effect transistor, respectively. In (D), 1 is a substrate, 2 is a gate electrode, 3 is a gate insulating layer, 4 is a semiconductor layer, 5 is a source electrode, and 6 is a drain electrode, and the bottom gate / bottom contact shown in FIG. Type, bottom gate / top contact type shown in FIG. 1 (B), top gate / bottom contact type shown in FIG. 1 (C), and top gate / top contact type shown in FIG. 1 (D). Further, although not shown, a protective layer may be formed on the uppermost portion of each field effect transistor in the drawing.

  In these field effect transistors, the substrate 1 can be the same substrate as that used in the conventional field effect transistor among those described above as the substrate of the semiconductor device, and has a thickness of 0.01. It is preferably in the range of -10 mm, particularly preferably in the range of 0.05-2 mm. Further, the substrate may be a laminated body composed of a plurality of layers.

  In the field effect transistor, the gate electrode 2 can be made of the same conductive material as that used in the conventional field effect transistor among those described above as the electrode of the semiconductor device, and the thickness thereof is It is preferably 1 to 100 nm, particularly preferably 10 to 50 nm.

In the field effect transistor, the gate insulating layer 3 can be made of a material used in a conventional field effect transistor. For example, organic materials such as polymethyl methacrylate, polystyrene, polyvinyl phenol, polyimide, polycarbonate, polyester, polyvinyl alcohol, polyvinyl acetate, polyurethane, polysulfone, epoxy resin, phenol resin, etc., and silicon dioxide, aluminum oxide, Examples include inorganic materials such as oxides such as titanium oxide, nitrides such as silicon nitride, and ferroelectric oxides such as SrTiO ₃ and BaTiO ₃ . A mixture of an organic material and an inorganic material is also used, and examples thereof include the organic polymer in which particles of the oxide, nitride, ferroelectric oxide, etc. are dispersed.

  In addition, the gate insulating layer is a coating method such as spin coating or blade coating, a vapor deposition method, a sputtering method, a printing method such as screen printing or inkjet, a method of forming an oxide film on a metal such as alumite on aluminum, etc. It can be formed by a method according to material characteristics, and the thickness thereof is preferably 0.1 to 4 μm, particularly preferably 0.2 to 2 μm. In general, as the capacitance of the gate insulating layer increases, the gate voltage can be driven at a low voltage, which is advantageous. For this purpose, an insulating material having a large dielectric constant is used, or the thickness of the insulating layer is reduced. It can be handled by making it thinner.

In the present invention, the gate insulating layer of the field effect transistor is preferably made of an organic polymer, the glass transition point of the organic polymer is more preferably 80 ° C. or higher, and the glass transition point is 100 ° C. or higher. It is particularly preferred. If the glass transition point is lower than the above range, the fluidity is too high, and softening during the lamination of other layers or heating to easily cause non-uniform film thickness or surface irregularities as a gate insulating layer. It tends to be difficult to maintain the stratum. It is preferable that the substrate is soluble in a solvent that does not dissolve the lower layer when the gate insulating layer is formed, and has a solvent resistance that is not eroded by the solvent when forming the upper layer such as a semiconductor layer. The gate insulating layer preferably has an electric conductivity of 10 ⁻¹² S / cm or less at room temperature because it relates to leakage current to the gate electrode and low gate voltage driving of the field effect transistor. ^It is particularly preferably ^-14 S / cm or less, and the relative dielectric constant is preferably 2.0 or more, particularly preferably 2.5 or more.

  In the field effect transistor, the source electrode 5 is an electrode through which current flows from the outside through the wiring, and the drain electrode 6 is an electrode for sending current to the outside through the wiring, and is provided in contact with the semiconductor layer 4 described above. ing. In the field effect transistor of the present invention, the source electrode 5 and the drain electrode 6 can be made of the same conductive materials as those used in the conventional field effect transistor among those described above as the electrodes of the semiconductor device. The thickness is preferably from 1 to 100 nm, particularly preferably from 10 to 50 nm. The distance between the source electrode and the drain electrode (channel length L) is preferably 100 μm or less, particularly preferably 50 μm or less, and the channel width W is preferably 2,000 μm or less. , 500 μm or less is particularly preferable, L / W is preferably 0.1 or less, and particularly preferably 0.05 or less.

In the present invention, the field effect transistor preferably has a mobility μ of 10 ⁻² cm ² / (V · s) or more, and particularly preferably 10 ⁻¹ cm ² / (V · s) or more. Further, it is preferable the threshold voltage V _t is 30V or less in absolute value, and particularly preferably 25V or less. Further, the On / Off ratio is preferably 10 ² or more, particularly preferably 10 ³ or more.

3-2. Static induction transistor (SIT)
In the present invention, another example of the semiconductor device is an electrostatic induction transistor (SIT) shown in FIG. In the above-described field effect transistor, the source electrode 5 and the drain electrode 6 are arranged in parallel on the substrate 1, and the direction of current flow is perpendicular to the electric field induced by the gate electrode 2, whereas electrostatic induction is performed. In the transistor, a source electrode 5 and a drain electrode 6 are arranged in a column on the substrate 1 with a semiconductor layer 4 interposed therebetween, and a gate electrode insulated by a gate insulating layer 3 (not shown) in the semiconductor layer 4 therebetween. 2 is arranged in a mesh shape, a stripe shape, a lattice shape, or the like at a predetermined interval, and the current flowing direction is parallel to the electric field induced by the gate electrode 2. Is different.

  And, in the electrostatic induction transistor, since the cross-sectional area of the channel, which is the sum of the cross-sectional areas of the plane perpendicular to the source-drain direction of the channel region, can be made larger than that of the field effect transistor, a large number of the cross-sectional areas can Carriers can be moved from the source electrode to the drain electrode and from the drain electrode to the source electrode, and the distance between the source electrode and the drain electrode can be reduced because the source electrode and the drain electrode are arranged in tandem. The response is fast, and it is suitable for use in applications where a large current flows or high-speed switching is performed.

  In the electrostatic induction transistor, the distance between the gate electrodes 2 is arbitrary, but is usually preferably smaller than the distance between the source electrode 5 and the drain electrode 6 (thickness of the semiconductor layer 4). The thickness of the gate electrode 2 is preferably 10 nm to 10 μm, particularly preferably 20 nm to 1 μm.

3-3. Diode In the present invention, another example of the semiconductor device includes a diode shown in FIGS. 3A and 3B. The diode is a two-terminal element having an asymmetric structure. As a typical example, the diode has a structure in which the semiconductor layer 4 is sandwiched between two metal electrodes 7 and 8 having different work functions as shown in FIG. Things. At least one of the metal electrodes 7 or 8 needs to form an energy barrier with the semiconductor layer 4. Aluminum is often used as a metal that forms an energy barrier with a p-type semiconductor, but an energy barrier is formed if the work function differs between the semiconductor and the electrode. When a voltage is applied to such an element, the flowing current is different when the polarity is reversed, and a rectifying action occurs.

  As another representative example, as shown in FIG. 3B, the semiconductor layer 4 formed from the semiconductor device manufacturing ink of the present invention and another semiconductor layer 9 having a significantly different work function are brought into contact with each other. The thing of the structure pinched | interposed between the metal electrodes 7 and 8 is mentioned. The metal electrodes 7 and 8 in this case may be the same or different. Examples of the semiconductor material of the other semiconductor layer 9 include perylene pigments, phthalocyanine materials, fullerenes, and conjugated polymers.

3-4. Others It is also possible to produce a two-terminal element having a symmetric structure. The resistance between the electrodes can be adjusted to be used as a resistor, or the resistance can be increased to adjust the electric capacity between the electrodes to be used as a capacitor. Such a resistance element has a merit that device parameters such as a resistance value can be widely controlled by a semiconductor layer formed from the ink of the present invention, which is convenient for integration. In addition, a low resistance material can be used for wiring.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

<Synthesis of Bicycloporphyrin Copper Complex>
S. Ito, N .; Ochi, T .; Murashima, H .; Uno, N .; Ono, Heterocycles, vol. According to the method described in 52,399 (2000), a bicycloporphyrin copper complex was synthesized from bicycloporphyrin by the following route. That is, 92.8 mg (0.16 mmol) of bicycloporphyrin having the following structure and 313.6 mg (1.6 mmol) of copper (II) acetate dihydrate were dissolved in a mixture of chloroform 150 mL / methanol 15 mL and stirred for about 1 hour. did. Since it was confirmed by alumina TLC (developing solvent chloroform / hexane = 1: 1) that the raw material disappeared and a new compound was formed, the reaction was stopped by adding water, and the organic solvent was washed with water as it was. The layers were separated. Furthermore, after washing with saturated saline, it was dried over anhydrous sodium sulfate. After the desiccant was filtered through filter paper, the solvent was distilled off, and chromatography was performed using alumina gel (developing solvent chloroform / hexane = 1: 1), and only fractions containing only the target product were collected and concentrated. When methanol was added during the concentration and the concentration was continued further, a precipitate of the desired product was formed. This was filtered off using filter paper and vacuum dried. The yield of the bicycloporphyrin copper complex thus obtained was 76.5 mg, and the yield was 75%.

  0.8 mg of the obtained bicycloporphyrin copper complex was dissolved in 1.25 g of chloroform and spin-coated on a glass substrate at 2,000 rpm to form a film. The obtained film was heated at 4 ° C./min. The absorption spectrum was measured. The result is shown in FIG. From this, as shown below, it can be seen that the conversion from the bicycloporphyrin copper complex to the benzoporphyrin copper complex occurs between 120 and 180 ° C.

Comparative Example 1
7 mg of the bicycloporphyrin copper complex obtained in the above synthesis example was dissolved in 1 g of chloroform at 25 ° C. and filtered through a 0.2 μm filter to prepare an ink 1 for producing a semiconductor device. The ink 1 had a surface tension of 27.1 mN / m, a viscosity of 0.56 mPa · s, and a boiling point of 61 ° C. When this ink 1 was stored at 25 ° C. in the atmosphere for 24 hours and the change in the amount of solvent was measured, it was found to be 16% by weight. Further, it was confirmed that the bicycloporphyrin copper complex was slightly precipitated as the solvent was reduced.

  On the other hand, on the oxide film of an N-type silicon substrate (Sb-doped, resistivity 0.02 Ωcm or less, manufactured by Sumitomo Metal Industries) having an oxide film having a thickness of 300 nm formed on the surface as a gate insulating layer, a gap ( L) A source electrode and a drain electrode were formed so as to have a channel of 10 μm and a width (W) of 500 μm. In addition, an oxide film different from this electrode is etched with a hydrofluoric acid / ammonium fluoride solution, gold is deposited on the exposed silicon substrate, and a voltage is applied to the silicon substrate (gate electrode). An electrode was obtained.

  Subsequently, the semiconductor device manufacturing ink 1 after the storage is spin-coated at 1,000 rpm on the substrate on which the electrode is formed, and then placed on a hot plate heated to 120 ° C., and then 10 ° C. every 15 minutes. By heating up to 200 ° C. in steps and heating, an organic semiconductor layer made of a benzoporphyrin copper complex having a thickness of 100 nm was formed, and a field effect transistor FET-A was produced. The above film formation and the following evaluation of the electric characteristics of the field effect transistor were all performed in a nitrogen atmosphere.

When the mobility μ, threshold voltage V _t , and On / Off ratio of the obtained field effect transistor FET-A were measured by the following method using a semiconductor parameter analyzer “4155C” manufactured by Agilent Technologies, the mobility μ Was 0.25 cm ² / (V · s), the threshold voltage V _t was 34 V, and the On / Off ratio was 1.4 × 10 ³ .

<Mobility μ, threshold voltage V _t >
The current flowing with respect to the voltage V _d applied between the source electrode and the drain electrode is I _d , the voltage applied to the source electrode and the gate electrode is V _g , the threshold voltage is V _t , per unit area of the gate insulating layer When the capacitance is C _i , the distance between the source electrode and the drain electrode is L, the width is W, and the mobility of the semiconductor layer is μ, the operation can be expressed by the relationship of the following formula (1) or (2). Measure the change in I _d for different V _g, find the mobility μ as the slope in the graph plotting I _d ^1/2 and V _g, and find the threshold voltage V _t from the I _d intercept of the graph It was.
When V _d <V _g −V _{t
I d = μC i (W /} L) _{[(V g -V t) V d} - (V d 2/2) ] (1)
When Vd> Vg
I _d = (1/2) μC _i (W / L) (V _g −V _t ) ² (2)

<On / Off ratio>
The voltage V _d applied between the source electrode and the drain electrode is fixed to −30 V, and the voltage V _g applied to the source electrode and the gate electrode flows between the source electrode and the drain electrode when set to −50 V and +30 V. The currents I _d (−50 V) and I _d (+30 V) were measured, and the On / Off ratio was calculated from these ratios I _d (−50 V) / I _d (+30 V).

Example 1
7 mg of the bicycloporphyrin copper complex obtained in the above synthesis example was dissolved in 1 g of anisole at 25 ° C. and filtered through a 0.2 μm filter to prepare an ink 2 for producing a semiconductor device. The ink 2 had a surface tension of 34.2 mN / m, a viscosity of 1.20 mPa · s, and a boiling point of 153 ° C. When this ink 2 was stored in the atmosphere at 25 ° C. for 24 hours and the change in the amount of solvent was measured, no decrease was observed. In addition, precipitation of the bicycloporphyrin copper complex was not confirmed. Using this semiconductor device manufacturing ink 2 after storage, a field effect transistor FET-B was manufactured in the same manner as in Comparative Example 1 and the electrical characteristics were evaluated. As a result, the mobility μ was 0.31 cm ² / ( V · s), the threshold voltage V _t was 19 V, and the On / Off ratio was 3.6 × 10 ⁴ .

Example 2
7 mg of the bicycloporphyrin copper complex obtained in the above synthesis example was dissolved in 1 g of ethyl benzoate at 25 ° C. and filtered through a 0.2 μm filter to prepare an ink 3 for producing a semiconductor device. The ink 3 had a surface tension of 35.4 mN / m, a viscosity of 1.96 mPa · s, and a boiling point of 213 ° C. When this ink 3 was stored at 25 ° C. in the air for 24 hours and the change in the amount of solvent was measured, no decrease was observed. In addition, precipitation of the bicycloporphyrin copper complex was not confirmed. Using the semiconductor device manufacturing ink 3 after storage, a field effect transistor FET-C was manufactured in the same manner as in Comparative Example 1 and the electrical characteristics were evaluated. As a result, the mobility μ was 0.36 cm ² / ( V · s), the threshold voltage V _t was 20 V, and the On / Off ratio was 2.7 × 10 ⁴ .

Example 3
7 mg of the bicycloporphyrin copper complex obtained in the above synthesis example was dissolved in 1 g of tetralin at 25 ° C. and filtered through a 0.2 μm filter to prepare an ink 4 for producing a semiconductor device. The ink 4 had a surface tension of 35.5 mN / m, a viscosity of 2.02 mPa · s, and a boiling point of 207 ° C. When this ink 4 was stored in the atmosphere at 25 ° C. for 24 hours and the change in the amount of solvent was measured, no decrease was observed. In addition, precipitation of the bicycloporphyrin copper complex was not confirmed. Using this semiconductor device manufacturing ink 4 after storage, a field effect transistor FET-D was prepared in the same manner as in Comparative Example 1 and the electrical characteristics were evaluated. As a result, the mobility μ was 0.26 cm ² / ( V · s), the threshold voltage V _t was 26 V, and the On / Off ratio was 7.2 × 10 ³ .

Example 4
7 mg of the bicycloporphyrin copper complex obtained in the above synthesis example was dissolved in 1 g of cyclohexanone at 25 ° C. and filtered through a 0.2 μm filter to prepare an ink 5 for producing a semiconductor device. The ink 5 had a surface tension of 34.5 mN / m, a viscosity of 2.20 mPa · s, and a boiling point of 155 ° C. When this ink 5 was stored in the atmosphere at 25 ° C. for 24 hours and the change in the amount of solvent was measured, no decrease was observed. In addition, precipitation of the bicycloporphyrin copper complex was not confirmed. Using the semiconductor device manufacturing ink 5 after storage, a field effect transistor FET-E was manufactured in the same manner as in Comparative Example 1 and the electrical characteristics were evaluated. As a result, the mobility μ was 0.29 cm ² / ( V · s), the threshold voltage V _t was 18 V, and the On / Off ratio was 3.1 × 10 ⁴ .

Example 5
7 mg of the bicycloporphyrin copper complex obtained in the above synthesis example was dissolved in 1 g of phenetole at 25 ° C. and filtered through a 0.2 μm filter to prepare an ink 6 for producing a semiconductor device. The ink 6 had a surface tension of 32.8 mN / m, a viscosity of 1.16 mPa · s, and a boiling point of 172 ° C. When this ink 6 was stored at 25 ° C. in the air for 24 hours and the change in the amount of solvent was measured, no decrease was observed. In addition, precipitation of the bicycloporphyrin copper complex was not confirmed. Using the semiconductor device manufacturing ink 6 after storage, a field effect transistor FET-F was manufactured in the same manner as in Comparative Example 1 and the electrical characteristics were evaluated. As a result, the mobility μ was 0.32 cm ² / ( V · s), the threshold voltage V _t was 22 V, and the On / Off ratio was 1.6 × 10 ⁴ .

Example 6
In Example 1, a field effect transistor FET-G was prepared in the same manner as in Example 1 except that the dip coating method was used instead of the spin coating method as the method of applying the semiconductor device manufacturing ink 2, and the electrical characteristics of As a result of the evaluation, the mobility μ was 0.37 cm ² / (V · s), the threshold voltage V _t was 27 V, and the On / Off ratio was 9.9 × 10 ³ . The dip coating method employed a method in which the silicon substrate on which the electrodes were formed was dipped in a beaker filled with the semiconductor device manufacturing ink 2 and then pulled up at a speed of 5 mm / min while applying hot air with a dryer.

Example 7
In Example 1, a field effect transistor FET-H was produced in the same manner as in Example 1 except that the blade coating method was used instead of the spin coating method as the coating method of the semiconductor device production ink 2, and the electrical characteristics of As a result of the evaluation, the mobility μ was 0.29 cm ² / (V · s), the threshold voltage V _t was 30 V, and the On / Off ratio was 3.0 × 10 ³ . The blade coating method was a method in which the semiconductor device manufacturing ink 2 was applied to the silicon substrate on which the electrodes were formed with a stainless steel simple blade coater at a speed of 3 mm / min.

Example 8
In Example 1, a field effect transistor FET-I was prepared in the same manner as in Example 1 except that the spray coating method was used instead of the spin coating method as the method for applying the semiconductor device manufacturing ink 2, and the electric characteristics of the semiconductor device were prepared. When evaluated, the mobility μ was 0.39 cm ² / (V · s), the threshold voltage V _t was 29 V, and the On / Off ratio was 9.5 × 10 ³ . In the spray coating method, a semiconductor device manufacturing ink 2 is applied to a silicon substrate on which electrodes are formed using a piece container (nozzle 0.2 mm, cup capacity 0.3 cc main body, operation method push button type) manufactured by OLYMPOS. The method of wiping was taken.

Example 9
In Example 1, a field effect transistor FET-J was produced in the same manner as in Example 1 except that the inkjet printing method was used instead of the spin coating method as the coating method of the semiconductor device production ink 2, and the electric characteristics of As a result of the evaluation, the mobility μ was 0.30 cm ² / (V · s), the threshold voltage V _t was 21 V, and the On / Off ratio was 6.5 × 10 ⁴ . In the inkjet printing method, a bank is formed around the electrode using a negative photoresist (“ZPN1100” manufactured by Nippon Zeon Co., Ltd.) on the silicon substrate on which the electrode is formed, and then 1 cm above the electrode on which the bank is formed. A method was adopted in which a microsyringe filled with semiconductor device manufacturing ink 2 was fixed and 200 pL was dropped to perform inkjet printing.

Example 10
In Example 1, a field effect transistor FET-K was prepared in the same manner as in Example 1 except that the contact printing method was used instead of the spin coating method as a method for applying the semiconductor device manufacturing ink 2, and the electrical characteristics of was evaluated, the mobility μ is ^{0.33cm 2 / (V · s)} , the threshold voltage V _t is 20V, On / Off ratio was 4.7 × 10 ^4. The contact printing method employs a method in which a silicon rubber stamp (manufactured by Next Eye) dipped in the semiconductor device manufacturing ink 2 is contact printed on the electrode on the substrate on the silicon substrate on which the electrode is formed. .

  A semiconductor device manufactured using the semiconductor device manufacturing ink of the present invention can be used as a switching element of an active matrix of a display. This is because the current applied between the source electrode and the drain electrode can be switched by the voltage applied to the gate electrode, and the switch is turned on only when a voltage is applied to or supplied to a certain display element, and the circuit is used for other times. By cutting the line, high-speed and high-contrast display is performed. Examples of the display element to be applied include a liquid crystal display element, a polymer dispersion type liquid crystal display element, an electrophoretic display element, an electroluminescence element, and an electrochromic element.

  In particular, the semiconductor device according to the present invention can be manufactured by a low-temperature process, can use a substrate that cannot withstand high-temperature processing such as plastic and paper, and can be manufactured by a coating or printing process. Therefore, it is also suitable for application to large area displays. Moreover, it is advantageous as an element capable of energy saving and a low cost process as an alternative to the conventional active matrix.

  Further, by integrating transistors, a digital element or an analog element can be realized. Examples of these include logic circuits such as AND, OR, NAND, NOT, memory elements, oscillation elements, amplification elements, and the like. Furthermore, an IC card, an IC tag, etc. can also be produced by combining these.

  In addition, an organic semiconductor may be applied to a sensor by taking advantage of the fact that the characteristics of the organic semiconductor change greatly due to external stimuli such as gas, chemical substance, and temperature. For example, by measuring the amount that changes due to contact with gas or liquid, it is possible to qualitatively or quantitatively display the chemical substances contained therein.

It is a longitudinal cross-sectional view which shows the typical structure of the field effect transistor as a semiconductor device by this invention. It is a longitudinal cross-sectional view which shows the typical structure of the electrostatic induction transistor as a semiconductor device by this invention. It is a longitudinal cross-sectional view which shows the typical structure of the die auto as a semiconductor device by this invention. It is an absorption spectrum at the temperature of 120-180 degreeC of the bicycloporphyrin copper complex used by the Example and the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Gate electrode 3 Gate insulating layer 4 Semiconductor layer 5 Source electrode 6 Drain electrode 7 Metal electrode 8 Metal electrode 9 Semiconductor layer

Claims (5)

A solution in which the concentration of the porphyrin compound represented by the following general formula (Ia) or (Ib) is 0.1% by weight or more is a basic component, the surface tension is 10 to 10 mN / m, and the viscosity is 1.0 to 50 mPa · s, a boiling point of 75 to 250 ° C., an ink for producing a semiconductor device.

[In formulas (Ia) and (Ib), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently have a hydrogen atom, a hydroxyl group, or a substituent. R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² each independently represents a hydrogen atom, a monovalent organic group, an amino group, a nitro group, a monovalent organic group, or a halogen atom, which may be Or, it represents a halogen atom, and M represents a metal atom. ] The ink for manufacturing a semiconductor device according to claim 1, wherein the solvent of the solution is any one selected from the group consisting of a ketone solvent, an ester solvent, and a halogen-free aromatic solvent. A method for producing a semiconductor device, wherein the semiconductor layer is formed by applying the ink for producing a semiconductor device according to claim 1 or 2 onto a surface on which the semiconductor layer is to be formed and drying. 4. The semiconductor device according to claim 3, wherein the coating method is any one selected from the group consisting of a spin coating method, a dip coating method, a blade coating method, a spray coating method, an ink jet printing method, and a contact printing method. Manufacturing method. The method for manufacturing a semiconductor device according to claim 3 or 4, wherein the semiconductor device is a field effect transistor.

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