Effect of Carrier Transport Process on Tunneling Electroresistance in Ferroelectric Tunnel Junction

We demonstrate the factors that determine the tunneling electroresistance (TER) of the ferroelectric tunnel junction (FTJ) by investigating the effects of temperature ( ${T}$ ) and the number of cycles ( ${N}{)}$ on remnant polarization ( ${P}_{\text {r}}{)}$ and carrier transport process. The fabricated FTJs have a metal/ferroelectric/insulator/semiconductor structure. The ${P}_{\text {r}}$ is increased with increasing ${T}$ and ${N}$ due to oxygen vacancy redistribution. However, the increased ${P}_{\text {r}}$ in a higher ${T}$ and ${N}$ does not improve the TER ratio. Using current-voltage characterization and low-frequency noise spectroscopy, we reveal that the carrier transport process at the interface between the ferroelectric and dielectric layers becomes more important than ${P}_{\text {r}}$ in determining the TER ratio.