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Ferroelectric field-effect transistors (FeFETs) composed of P(VDF-TrFE) (Poly(Vinylidenefluoride-Tirfluoroethylene)) thin films and semiconductor substrates show excellent ferroelectric transistor characteristics. Since P(VDF-TrFE) has the ferroelectricity as large as those of oxide ferroelectric materials with much lower dielectric constant, it is the ideal material to build FeFET with the combination to inorganic semiconductor material. In addition, the process condition to form P(VDF-TrFE) is much milder to underlying semiconductingmaterial compared to oxide ferroelectrics. Therefore, the improvement on the retention characteristics is expected by employing P(VDF-TrFE) ferroelectrics in FeFET instead of oxide ferroelectrics. The potential of P(VDF-TrFE) FeFET is discussed in this chapter. [ABSTRACT FROM AUTHOR]

We developed high-performance metal-ferro-electric-insulator-semiconductor (MFIS) structures with a thin Al 2 O 3 layer deposited on Si 3 N 4 buffer layer. The Al 2 O 3 were deposited by atomic layer deposition technique and the Si 3 N 4 were made by the direct nitridation of Si substrate using atomic nitrogen radicals. Since the buffer Si 3 N 4 was made perfectly damage-free and hydrogen-free, we can perform high temperature oxidation to eliminate defects in Al 2 O 3 and ferroelectric films down to the negligible level. On the stacked buffer layer, we deposited highly c-axis oriented Bi 3.25 La 0.75 Ti 3 O 12 film and fabricated MFIS structure. With the help of the high insulating property of a buffer layer and a highly c-axis oriented ferroelectric film, we succeeded to realize the large memory windows together with the long retention characters in the Pt/Bi 3.25 La 0.75 Ti 3 O 12 /Al 2 O 3 /Si 3 N 4 /Si MFIS structure. [ABSTRACT FROM AUTHOR]

We demonstrated flexible ferroelectric gate thin-film transistors (Fe-TFTs) with ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and amorphous indium gallium zinc oxide (a-IGZO) channel on the polyethylene-naphthalate (PEN) substrate. First, we confirm basic ferroelectric properties of the P(VDF-TrFE) film on the PEN substrate with various bending radius. Next, we fabricated Fe-TFTs with Al/120 nm-P(VDF-TrFE)/40 nm-IGZO top gate structure. Excellent electrical characteristics are demonstrated and nonvolatile memory function was confirmed with a memory window of 8.4 V. A subthreshold voltage swing of 400 mV/decade, Ion/Ioff ratio of more than 107 and the field-effect mobility of ∼1 cm2/Vs were obtained. [ABSTRACT FROM AUTHOR]