Fizika Tverdogo Tela, 2022 Volume 64, Issue 5,Pages 556–559(Mi ftt11011)
Ferroelectricity
The effect of a strong static electric field and heating on characteristics of the high-frequency impedance of metal–ferroelectric–semiconductor structures
Abstract:
Studies have been carried out on the effect of heating and a strong field, but pre-breakdown, effects on high-frequency characteristics of the impedance of heteroepitaxial structures Ni–Ba$_{0.8}$Sr$_{0.2}$TiO$_3$–$p$Si with a ferroelectric thickness of 50 nm. It was shown, that regardless of the polarity of the field stress, characteristics shifted towards a positive bias, and the width of hysteresis loops decreased; plateau levels remained virtually unchanged. Heating up to 121$^\circ$C led to a change in levels of the upper plateau of characteristics: for the capacity it decreased, and for the conductivity it increased; branches on the loop not only narrowed and shifted, but changed places in comparison with the original dependence (loop reverse). These results can be explained: under the field action, by the generation of additional electronic states, localized in the buffer layer at the Ba$_{1-x}$Sr$_x$TiO$_3$ interface, and by heating, by the appearance of delay effects due to the development of fluctuation processes, underlying the smearing of the phase transition from ferroelectric to paraelectric condition.
Keywords:high-frequency field characteristics of the impedance, the field stress, hysteresis loops, the generation of additional localized electronic states, delay effects, fluctuation processes, smearing of the phase transition.