Two resistive switching regimes in thin film manganite memory devices on silicon

Abstract

Bipolar resistive switching in low cost n-Si/La2/3Ca1/3MnO3/M (M = Ti + Cu) devices was investigated. For low SET compliance currents (CC), an interfacial-related resistive switching mechanism, associated to the migration of oxygen vacancies close to the manganite/metal interface, is operative. Simulations using the voltage enhanced oxygen vacancies drift model validate our experimental results. When further increasing the CC, we have observed the onset of a second, filamentary, resistive switching regime with a concomitant collapse of the ON/OFF ratio. We finally demonstrate that it is possible to delay the onset of the filamentary regime by controlling the film thickness.

Manganite-based three level memristive devices with self-healing capability

“…On the other hand, the electrode material plays a key role, determining overall resistance levels by the introduction of a naturally formed oxide layer [9] or through the migration of metallic ions (i.e. metallic filament formation) [8,10]. Besides, manganite based non-volatile memory devices exhibit multilevel capability [11] sustained on the controlled electric field drift of vacancies [12], with the ability to tune (almost) continuously the actual resistance level.…”

“…Here we focus on a manganese oxide multifunctional compound, La 1/3 Ca 2/3 MnO 3 (LCMO), a unique manganite well known for its colossal magnetoresistance and intrinsic phase separation effects [5]. Manganite based RS non-volatile memory devices were shown to exhibit unique properties, either in polycrystalline [6] or thin film [7,8] format. Electronic transport in manganites is described by electron hopping between neighbor Mn sites.…”

Origin of multistate resistive switching in Ti/manganite/SiOx/Si heterostructures

“…Phenomenological models that successfully describe the electrical behavior have been developed [18,19]. Proposed mechanisms associated to the memristive behavior in manganites include the modulation of the height of the Schottky barrier at the oxide/metal interface [20], the oxidation/reduction of a thin layer of the metallic electrode in contact with the manganite [22] and the creation/disruption of conducting (metallic) filaments bridging both electrodes [20,22]. Concerning electronic transport, different mechanisms such as Poole-Frenkel (PF) [23], space charged limited current (SCLC) [24] or Schottky (Sch) conduction [25,26], have been reported for manganite-based devices.…”

“…We have already faced the study of memristive TE/La 2/3 Ca 1/3 MnO 3 (TE: Ti/Cu with thicknesses of 10 and 100nm, respectively) devices grown on heavily doped n-Si (which acted as bottom electrode) without removing the native SiO x layer [20]. It was found a bipolar RS behavior with a crossover between two of the above mentioned mechanisms -modulation of the metal/maganite interface resistance and metallic filament formationcontrolled by the compliance current (CC) programmed during the transition from high to low resistance states (SET process).…”

“…We recall that in that work the applied electrical stress was voltage and only two stable resistance states (R HIGH and R LOW ) were obtained. We argued that the time window of a few ms that standard source-meters take to stabilize the CC, leads to an uncontrolled power overshoot during the SET process (power P=V 2 /R) that induces the hard dielectric breakdown of the SiO x layer laying between the Si substrate and the manganite layer [27,20]. This unwanted effect could be avoided if the electrical stress is in current controlled mode because the dissipated power during the SET process remains self limited (P=I 2 R).…”