Influence of aging on the resistive switching behavior of epitaxial strontium titanate based heterostructures

Abstract

In this work, we investigated the impact of aging on the resistive switching behavior of high quality epitaxial heterostructure resistive switching devices [Pt/SrTiO3/LaNiO3/LaAlO3 (001) with SrTiO3 (STO) as switching layer, Pt as top electrode and LaNiO3 as bottom electrode]. For this study, the resistive switching memory devices of two different ultrathin switching layer (STO) thicknesses (5 and 10 nm) were fabricated with different shape and size of top electrode (Pt) i.e. 20 μm (circular shape) and 50 μm (square shaped). Subsequently, their resistive switching behavior at different instant of time i.e. freshly prepared, 4 months and 16 months were studied. With long aging, we find a decrease in the positive bais voltages for which current start rising exponentially (set voltages) for most of the devices besides emergence of various features such as multiple crossovers, noisy/spike region during set process and openness in the switching hysteresis loop. The existence of these behaviors is attributed to the fact that the moisture permeates through the interfacial region between top electrode (Pt) and switching layer (STO) irrespective of the thickness of switching layer and dimensions of top electrode.