The next generation of electronic devices requires faster operation velocity, higher storage capacity and reduction of the power consumption. In this context, resistive switching memory chips emerge as promising candidates for developing new non-volatile memory modules. Manganites have received increasing interest as memristive material as they exhibit a remarkable switching response. Nevertheless, their integration in CMOS-compatible substrates, such as silicon wafers, requires further effort. Here the integration of LaMnO3+δ as memristive material in a metal–insulator–metal structure is presented using a silicon-based substrate and the pulsed injection metal organic chemical vapour deposition technique. We have developed three different growth strategies with which we are able to tune the oxygen content and Mn oxidation state moving from an orthorhombic to a rhombohedral structure for the active LaMnO3+δ material. Furthermore, a good resistive switching response has been obtained for LaMnO3+δ-based devices fabricated using optimized growth strategies.

Manganite perovskites exhibit promising resistive switching properties, for which the understanding of the related microscopic physicochemical changes taking place is still rather scarce. In this work the resistance of a LaMnO3+δ thin film has been locally tuned within a range of 2 orders of magnitude using conductive atomic force microscopy. With the use of X-ray photoemission electron microscopy it has been possible to simultaneously unravel composition and work function modification related to changes in the LaMnO3+δ resistance state. The resistance change is found to be triggered by oxygen ions drifting to the surface, where they remain adsorbed. Concomitant to this oxygen displacement, the Mn oxidation state is reduced from +3.6 to +3.1, while the work function decreases by 0.28 eV. We discuss the effect of these physicochemical modifications on the conduction mechanism, which is in agreement with a space-charge-limited conduction (SCLC) mechanism where the current is restrained by the density of traps at the interface. We show that the resistive switching in the material can be described as a change of the transport regime from a trap-free to a trap-controlled SCLC, depending on the oxygen content in the material.

Transition metal oxides are promising candidates in the development of valence change memories thanks to their ability to present valence change mechanism. The resistive switching mechanism of TiN/LaMnO3+/Pt devices was investigated by operando hard X-ray photoelectron spectroscopy after careful in situ electrical characterization. The results presented here highlight the oxygen exchange process at the TiN/LMO interface. The active TiN top electrode acts as an oxygen getter, pumping O 2anions which are attracted by the positive bias and repelling them under negative bias. This drift of charged defects is correlated with variations of the interfacial resistance. Our results confirm the critical role of the TiN/LMO interface as well as of oxygen drift in the resistive switching behaviour of such devices.