Characteristics of metal/ferroelectric/insulator/semiconductor using La₂O₃ thin film as an insulator

We fabricated a novel metal/ferroelectric/insulator/semiconductor (MFIS) structure using the PbTiO₃ film and La₂O₃ film prepared by metal organic chemical vapor deposition as a ferroelectric and an insulator, respectively. The dielectric constant (k) of the 420 Å La₂O₃ film was about 28. The leakage current density was about 3 × 10^-6 A/cm² at +5 V. The MFIS using an Al/PbTiO₃ (3600 Å)/La₂O₃ (280 Å)/Si configuration showed clockwise C-V hysteresis. The memory window increased from 0.3 to 2.6 V with increasing bias from 2 to 10 V. In this letter we propose the La₂O₃ film as an alternative insulator layer in the MFIS structure.