The density of interface states and their relaxation times in Au/Bi4Ti3O12/SiO2/n‐Si(MFIS) structures

Bismuth titanate (Bi₄Ti₃O₁₂) (BTO) thin films were fabricated on an n‐type Si substrate and annealed by rapid thermal annealing methods. The I‐V measurement shows that the device has properties of Schottky diode with the Φ_B0 of 0.76 eV, n of 2.42, and leakage current of about 10^?7 A at ? 8 V. The experimental C‐V‐f and G/w‐V‐f characteristics of metal‐ferroelectric‐insulator‐semiconductor (MFIS) structures show fairly large frequency dispersion especially at low frequencies due to interface states N_ss. The energy distribution of (N_ss) has been determined by using the high‐low frequency capacitance (C_HF? C_LF) and conductance method. The relaxation time (τ) of interface states was calculated from the conductance method. It has been shown that both the N_ss and relaxation time increase almost exponentially with bias, which activates traps located at deeper gap energies. Copyright © 2011 John Wiley & Sons, Ltd.