Abstract: Provided is a field-effect transistor which has a high mobility and a low variation of mobility. A field-effect transistor at least comprising a substrate, a semiconductor layer, a source electrode, and a drain electrode is produced by forming the source electrode and/or the drain electrode so that the source electrode and/or the drain electrode has a taper shape in a cross-section which is parallel with a channel length direction and perpendicular to the substrate, and forming the semiconductor layer through coating process.

Abstract: Provided is an insulating layer that can improve device characteristics of an electronic device including the insulating layer. The insulating layer contains a polymer insulating substance having repeating units represented by the following formula: wherein Ra represents a direct bond or any linking group, Ar represents a divalent aromatic group optionally having a substituent, and Rb represents a hydrogen atom, a fluorine atom, or a univalent organic group.

Abstract: A field effect transistor including a gate insulation portion, an organic semiconductor portion, a source electrode and a drain electrode, wherein when a voltage is applied to the gate at 70° C. for 5.0±0.1 hours so that the field strength in the gate insulation portion would be 100±5 MV/m, the change in the threshold voltage is within 5 V. The organic semiconductor portion has a high driving stability, of which the change in characteristics by driving is thereby small.

Abstract: Provided is a field-effect transistor which has a high mobility and a low variation of mobility. A field-effect transistor at least comprising a substrate, a semiconductor layer, a source electrode, and a drain electrode is produced by forming the source electrode and/or the drain electrode so that the source electrode and/or the drain electrode has a taper shape in a cross-section which is parallel with a channel length direction and perpendicular to the substrate, and forming the semiconductor layer through coating process.

Abstract: Provided is an insulating layer that can improve device characteristics of an electronic device including the insulating layer. The insulating layer contains a polymer insulating substance having repeating units represented by the following formula: wherein Ra represents a direct bond or any linking group, Ar represents a divalent aromatic group optionally having a substituent, and Rb represents a hydrogen atom, a fluorine atom, or a univalent organic group.

Abstract: Disclosed is an adequately stable organic semiconductor material which can be used in a coating process while having high regularity and crystallinity. For obtaining such an organic semiconductor material, there is used a compound wherein 6-20 five-membered and/or six-membered aromatic rings are bound. This compound contains a partial structure represented by the formula (1) below, while having a mobility of not less than 1.0×10?3 cm2/Vs and an ionization potential in the solid state of not less than 4.8 eV and not more than 5.6 eV. (1) In the formula, R1 and R2 independently represent a hydrogen atom or a monovalent organic group. In this connection, at least one of R1 and R2 is an optionally substituted aromatic group.

Abstract: A field effect transistor including a gate isulation portion, an organic semiconductor portion, a source electrode and a drain electrode, wherein when a voltage is applied to the gate at 70° C. for 5.0±0.1 hours so that the field strength in the gate insulation portion would be 100±5 MV/m, the change in the threshold voltage is within 5 V. The organic semiconductor portion has a high driving stability, of which the change in characteristics by driving is thereby small.

Abstract: A field effect transistor comprising, as provided on a support substrate, an insulation layer, a gate electrode and an organic semiconductor layer separated by the insulation layer, a source electrode and a drain electrode provided so as to contact the organic semiconductor layer, wherein elongation ?1 (%) at the yield point of the insulation layer is larger than elongation ?2 (%) at the yield point of the support substrate.

Abstract: The mechanical characteristics of the support substrate and the insulation layer of an organic field effect transistor are optimized to thereby attain a high mobility, a high on-current and a low leak current, and a high on/off ratio in the organic field effect transistor. A field effect transistor comprising, as provided on a support substrate 1, an insulation layer 3, a gate electrode 2 and an organic semiconductor layer 4 separated by the insulation layer, a source electrode 5 and a drain electrode 6 provided so as to contact the organic semiconductor layer 4, wherein elongation ?1 (%) at the yield point of the insulation layer is larger than elongation ?2 (%) at the yield point of the support substrate. It has good flexible characteristics, whereby cracking, etc. due to a stress exerted will be suppressed, and a leak current will thereby be reduced, and thus, a high mobility, a high on-current and a low leak current, and a high on/off ratio can be attained.