Fatigue characteristics of poly(vinylidene fluoride-trifluoroethylene) copolymer ferroelectric thin film capacitors for flexible electronics memory applications

The electrical fatigue characteristics of 100 nm thick, solution processed poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer thin film Metal-Ferroelectric-Metal (MFM) capacitors have been studied. After one million stress cycles at an electric field of 1.4 MV/cm and 500 Hz switching frequency, 87% of the initial switching polarization is maintained, with the non-switching polarization remaining low. The kinetics of the switching polarization were studied before and after electrical stress. Fatigue increases the required activation field for switching polarization and suppresses switchable polarization. The activation field increases after electrical stress and higher activation fields were required for higher electric field stressing. The reduction in switchable polarization is approximately 10% of the initial switching polarization for all electric fields and frequencies studied. We demonstrated that under operating conditions compatible with flexible electronic applications, the optimized ferroelectric thin film capacitor reported shows stable switching polarization and acceptable fatigue after electrical stress.