Ferroelectric-gate thin-film transistors using indium-tin-oxide channel with large charge controllability

We have fabricated and characterized ferroelectric-gate thin-film transistors (TFTs) using indium-tin-oxide (ITO) as a channel and ferroelectric Bi4-xLaxTi3O12 (BLT) as a gate insulator. We have obtained a typical n-channel transistor property with clear current saturation in drain current and drain voltage (I-D- V-D) characteristics. The obtained on/off current ratio is more than 10(4) and the field-effect mobility is estimated 9.1 cm(2)/Vs. In particular, we demonstrate a large on-current of 2.5 mA in ITO/BLT structure TFT in spite of the low channel mobility. This is because the ferroelectric film can induce large charge density due to the spontaneous polarization. (c) 2005 American Institute of Physics.