Influence
of dipolar alignments of a ferroelectric poly-vinylidine
fluoride trifluroethylene [P(VDF-TrFE)] thin film on the charge mobility
and nonvolatile property of ferroelectric field-effect transistors
(FeFETs) has been explored. The electrical properties of the ferroelectric
microstructures can be tuned by adopting different cooling procedures
after annealing the spin-coated ferroelectric polymer P(VDF-TrFE)
substrates. For example, a higher degree of alignment of the C–F
dipoles in the polymeric chains is observed along the substrate surface
for the samples with fast quenching. The dielectric constant of the
fast-quenched sample is found to be ∼10 at 1 kHz, while the
same is found to be ∼8.5 when the rate of cooling is relatively
slower. Furthermore, the fabrication of a metal–insulator–metal
capacitor using the fast-quenched substrate leads to a high remnant
polarization of P
r ∼ 5.5 ±
0.2 μC/cm2, as compared to that of the normally cooled
sample to ∼2.7 ± 0.2 μC/cm2, at an applied
field intensity of 200 MV/m. Emergence of such characteristics encouraged
the use of P(VDF-TrFE) as a gate dielectric layer, which leads to
improved nonvolatile characteristics of the device. The measured charge
carrier mobility of FeFETs embedded with a fast-quenched ferroelectric
polymer as a gate dielectric is found to be ∼3.4 × 10–2 cm2 V–1 s–1, which is ∼35% higher than the normally cooled samples. The
strongly correlated C–F dipoles in the fast-quenched ferroelectric
layers lead to the reduction in width of the trap density of states
near the semiconductor–dielectric interface. The XPS and UPS
characterizations show the formation of a superior transport channel
in the semiconductor near its dielectric interface when the fast-quenched
polymer is used as the gate dielectric in the FeFETs.