ELECTRICAL CHARACTERIZATIONS OF Bi_(3.25)La_(0.75)Ti_3O_(12) THIN FILMS ON THERMALLY OXIDIZED p-Si SUBSTRATES

摘要

A metal-ferroelectric-insulator-semiconductor (MFIS) diode was prepared using Bi_(3.25)La_(0.75)Ti_3O_(12) thin films onto thermally oxidized Si substrates. Results on the electrical properties include capacitance-voltage (C-V), memory window effect and current-voltage (I-V) characteristics. C-V properties for the SiO_2/Si structures showed an ideal switch from maximum to minimum capacitance exactly at zero voltage without any presence of flatband voltage difference. Such property ensures ohmic contacts of the electrodes and that the Au/SiO_2/Si/Al diodes have fairly good interfacial properties. As for the MFIS-diodes, the flatband voltage difference enlarges at increasing voltages, exhibiting a memory window effect from ferroelectric polarization. The positive voltage sweep was measured to be identical at increasing bias voltages. Such unusual property may arise from the sudden increase in current density at about 0.9 V from I-V measurements.