| 摘要 |
PURPOSE:To reduce the OFF-current by a method wherein a gate electrode is provided also in the lower part of a semiconductor thin film via gate insulation film, and the thin film transistor is driven by application of a constant voltage in the neighborhood of a flat band voltage at the lower part interface on this electrode. CONSTITUTION:When the difference in work functions between the lower gate electrode and the semiconductor thin film is phiMS', the interface level of the lower interface QSS, the static capacitance of the lower gate insulation film C0, the film thickness of the gate insulation film x0, and the charge density in the gate insulation film rho(x), the flat band voltage VFB at the lower interface can be expressed by the formula I . Therefore, application of a voltage in the neighborhood of a constant voltage VFB on the lower gate electrode 41 causes the prevention of the bending of the band and then enables the OFF-current to be kept to a very small value. |
