Ambipolar Schottky-barrier TFTs

A novel Schottky-barrier metal-oxide-semiconductor thin-film transistor (SBTFT) was successfully demonstrated and characterized. The new SBTFT device features a fleld-induced-drain (FID) region, which is controlled by a metal field-plate lying on top of the passivation oxide. The FED region is sandwiched between the silicided drain and the active channel region. Carrier types and the conductivity of the transistor are controlled by the metal field-plate. The device is thus capable of ambipolar operation. Excellent ambipolar performance with on/off current ratios over 10(6) for both p- and n-channel operations was realized simultaneously on the same device fabricated with polysilicon active layer. Moreover, the off-state leakage current shows very weak dependence on the gate-to-drain voltage difference with the FID structure. Finally, the effects of FED length are explored.