Organic thin-film transistor and method for manufacturing organic thin-film transistor

Abstract

Disclosed are an organic thin-film transistor and a manufacturing comprising thereof, the organic thin-film transistor comprising a support and provided thereon, a gate electrode, an insulation layer, a source electrode, a drain electrode, and an organic semiconductor layer, the support comprising at least one of resins, and the organic semiconductor layer containing at least one of organic semiconductor materials, wherein a phase transition temperature of one of the organic semiconducting materials is not more than a glass transition point of one of the resins.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an organic thin-film transistor and a manufacturing method thereof. BACKGROUND OF THE INVENTION [0002] In recent years, an organic thin-film transistor employing an organic semiconducting compound as a semiconductor channel has been studied. The organic semiconducting compound is easy in processing and high affinity to a plastic sheet support, as compared with an inorganic semiconducting compound, and therefore, is preferred in its application to a thin-film device. [0003] There is, for example, description in Japanese Patent O.P.I. Publication Nos. 9-232589 and 7-206599 that an orientation film increases carrier mobility in an organic semiconductor layer. [0004] Further, there is proposed technique in WO 0079617 that mobility of an organic semiconductor channel is increased by orientation treatment of the semiconductor which employs mesomorphism produced on heating a semiconducting polymer to not less than the a tempera...

AI Technical Summary

Benefits of technology

[0055] It is necessary that in the organic thin-film transistor of the invention, a phase transition temperature (° C.) of at least one of the organic semiconducting materials used is not more than a glass transition point (° C.) of at least one of resins constituting a support described later in obtaining the effects of the invention that the organic thin-film transistor has a high carrier (electron or hole) mobility and can employ conventional plastic materials or transparent resins as materials for the support.

[0056] The term, “a phase transition temperature of organic semiconducting materials”, herein referred to implies a melting point, a softening point, a secondary transition temperature (fro example, a glass transition point), or a phase transition point to liquid crystal phase. The phase transition temperature (liquid phase transition point) of the organic semiconducting materials used in the invention is preferably from 100 to 240° C.

[0057] It is especially preferred that the melting point or liquid phase transition point of the organic semiconducting materials is not more than a glass transition point (° C.) of at least one of resins constituting the support.

[0058] The melting point can be measured through an automatic melting point apparatus available on the market, and the phase transition point can be measured through a differential scanning calorimeter (DSC) available on the market. The phase transition behavior can be observed through a polarization microscope (POM). The higher order structure; relationship between crystallinity or liquid crystallinity and the molecular structure can be analyzed through X-ray diffraction (XRD). <<Forming Method of Organic Semiconductor Layer (Organic Thin-Film)>>

[0059] The methods for forming the organic semiconductor layer include a vacuum deposition method, a molecular beam epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a sputtering method, a plasma polymerization method, an electrolytic polymerization method, a chemical polymerization method, a spray coating method, a spin coating method, a blade coating method, a dip coating method, a casting method, a roll coating method, an bar coating method, a die coating method, an ink-jet method, and an LB method. These methods may be used according to kinds of materials used.

[0060] However, of these, the spin coating method, blade coating method, dip coating method, roll coating method, bar coating method, die coating method and ink-jet method are preferred from the viewpoint of productive efficiency, which can simply and accurately form the layer employing a solution of organic semiconductor materials. Further, an organic semiconductor layer may be formed, jetting a solution or dispersion of the organic semiconductor by ink jet and drying.

Problems solved by technology

Further, this requires a process of forming an orientation film adjacent to the semiconductor layer, which complicates constitution of a semiconductor element.

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