Analysis of AC electrical response for radio-frequency sputtered (Ba0.5Sr0.5)TiO3 thin film

Through the measurement of dielectric dispersion as a function of frequency (100 Hz less than or equal to f less than or equal to 1 MHz), we investiga ted the trapping dielectric relaxation of r.f.-sputtered (Ba0.5Sr0.5)TiO3 f ilm and proposed an equivalent circuit on the basis of the admittance and c apacitance spectra. Admittance spectral studies in the temperature range of 200-420 K revealed the existence of a trap level. The trap, located at 0.0 5 eV, is envisaged to be responsible for the origin of dielectric relaxatio n and carrier concentration. The equivalent circuit, consisting of a series trapping resistance and capacitance combination in parallel with leakage r esistance and high frequency limit capacitance, is adopted to explain satis factorily the AC response and to identify the contribution of the shallow t rap on the electrical properties of BST thin film. (C) 1999 Elsevier Scienc e S.A. All rights reserved.