Injected charge as a cause of the slow dielectric relaxation in thin film Pt/(Ba,Sr)TiO3/Cu structures

Experimental studies of the response of Pt/Ba0.3Sr0.7TiO3/Cu capacitors to switching-off the bias voltage are reported. The remnant capacitance as a function of the bias voltage and the variation of this capacitance with time have been measured and analyzed in terms of the injection model of the space charge origin with consideration for the linear dielectric layer at the Pt/BSTO interface. The energy depths, 0.51 eV, and 0.65 eV, of two trap states controlling the slow (τ ≈ 100 s and τ ≈ 5 × 103 s) space charge relaxation process have been extracted from experiments.