Nonvolatile memory transistors using solution-processed zinc–tin oxide and ferroelectric poly(vinylidene fluoride-trifluoroethylene)

The nonvolatile memory thin-film transistor (MTFT) using a solution-processed zinc–tin oxide (ZTO) semiconducting channel and a poly(vinylidene fluoride-trifluoroethylene) ferroelectric gate insulator was proposed. The crystalline phases of spin-coated ZTO films were essentially amorphous even when the films were annealed at 500 °C and the surface morphology was very smooth and uniform. Although the memory behaviors based on the ferroelectric field-effect were confirmed for all the fabricated MTFTs, the field-effect mobility, memory window, and the on/off ratio were markedly varied with the changes in annealing temperature and film composition of the ZTO channel. The origins for these differences were examined from the changes in electrical conductivities during the thermal process. The best device performances could be obtained for the MTFT using the 50/50 mol% ZTO channel annealed at 500 °C. The memory window at VGVG sweep of ±15V, field-effect mobility, subthreshold swing, and on/off   ratio were obtained to be approximately 8.1V,15.8cm2V-1s-1,1.1V/dec, and 6.4×1076.4×107, respectively.