Characteristics of Metal/Ferroelectric/Insulator/Semiconductor Structure Using SrBi 2Ta 2O 9 as the Ferroelectric Material

Abstract

We fabricated a metal/ferroelectric/insulator/semiconductor (MFIS) structure using SrBi₂Ta₂O₉ (SBT) as the ferroelectric material for the first time. The SBT thin film on CeO₂/Si (100) had (105), (110) and (200) orientation. Threshold hysteresis (called “memory window”) was observed in the capacitance-voltage ( C–V ) characteristics of this sample. The memory window was about 0.5 V. From the calculation of the C–V characteristics, it is estimated that the density of surface states at the CeO₂/Si interface increases upon deposition of SBT. By X-ray diffraction (XRD) analysis, diffusion of Si to the surface of SBT was detected. In order to prevent such diffusion it may be necessary to reduce the firing temperature.