Polarization behavior of poly(vinylidene fluoride-trifluoroethylene) copolymer ferroelectric thin film capacitors for nonvolatile memory application in flexible electronics

Abstract

The time domain and electric field dependence of the polarization switching kinetics of poly(vinylidene fluoride-trifluoroethylene) copolymer based thin film metal-ferroelectric-metal capacitors have been characterized. At room temperature, the time required for complete switching polarization decreases from >1 s to <50 μs as the voltage is increased from 6 to 12 V, while low nonswitching polarization is maintained. In the time domain, the ferroelectric switching polarization reversal behavior for devices biased above the coercive field follows the nucleation-limited-switching model. The exponential relationship between switching time and applied electric field indicates nucleation dominated switching kinetics. Switching behavior as a function of temperature was also characterized from −60 to 100 °C in the voltage range of 6–12 V. Higher temperatures induce larger dc conductance leakage at low frequencies and increases nonswitching polarization for all the voltages studied. It is demonstrated that for certain frequencies, by controlling the switching voltage, our optimized ferroelectric thin film capacitor shows stable switching polarization in a temperature range compatible with flexible electronics applications.

Low Temperature Processed Two-Transistor- Two-Capacitor-Based Ferroelectric Random Access Memory

“…The fabricated ferroelectric capacitor shows an average coercive voltage of ∼7.3 V (corresponding to a coercive field of 0.48 MV/cm). The remanent polarization (P r ) is ∼9.3 μC/cm 2 , slightly larger than previously achieved values [19], [26], [27], which is probably due to a larger dc leakage [26], [28].…”

“…The electrical performance of our 2T2C FRAM array can be further improved by enhancing the TFT channel mobility, Vt stability, quality of the ferroelectric film, and process integration. We have demonstrated <50-μs switching time and >1×10 6 stress cycle fatigue capability for the isolated ferroelectric capacitor [26], [27], [30]. Further study on the frequency response of the 2T2C FRAM array and reliability including memory window degradation during program/read stress, and data retention are important and needed for future development.…”

“…The data writing time t DW is programmed to be 200 ms (t DWH = t DWl = 1/2 t DW ), t WR is 300 ms, and all other ac time parameters are set to be 100 ms. The program and read times depend on applied voltage as discussed earlier in [26] and [30] and can be optimized for different applications. In Fig.…”

Improving information density in ferroelectric polymer films by using nanoimprinted gratings

“…Several approaches and prototypes have already been proposed, for example, metalpolymer-metal capacitors, [1][2][3][4][5] field-effect transistors, 6-9 and tunnel-junctions, 10 all of them based on thin polymer films, generally with thickness smaller than 100 nm, and with the possibility of a readily integration with flexible complementary metal oxide semiconductor devices or other organic electronic devices.…”

Induced magneto-electric coupling at ferroelectric/ferromagnetic interface

“…In PVDF, the dipoles are formed due to the electronegativity difference between the fluorine and hydrogen atoms. In this case, This velocity has been calculated for PVDF polymers based on the switching time for the dipoles [152]. Previous works have shown this velocity to be on the order of 10 3 m/s [153,154].…”