The electrical properties of single-crystalline Z-cut LiNbO₃ thin films fabricated by crystal-ion-slicing technique

Single-crystalline Z-cut lithium niobate (LiNbO₃, LN) thin film with a thickness of ~ 878 nm situated between top and bottom electrodes is fabricated depending on crystal-ion-slicing (CIS) technique and SiO₂ bonding method. Microstructure characteristics indicate that the LN thin film has a good crystalline quality and there is no obvious defects on the surface. Moreover, ferroelectric performances are intensively analyzed by the ferroelectric hysteresis loop measurements, which express a glorious rectangularity in spite of shifting to the forward electric field under the effect of internal polarization field. And when external electric field increases the polarization intensity approximates saturation at 900 kV/cm and the value is around 58 μC/cm². The great ferroelectric performances make it potential for the tunable filters based on the CIS-fabricated LN thin film in other cut directions. The leakage current is also measured in different direction bias and the conduction mechanism is further analyzed, which is dominated by Schottky emission mechanism and has no effect of bulk defects.