La₂NiO_4+δ‐Based Memristive Devices Integrated on Si‐Based Substrates

Abstract

Valence Change Memories, in which internal redox reactions control the change in resistance are promising candidates for resistive random access memories (ReRAMs) and neuromorphic computing elements. In this context, La2NiO4+δ (L2NO4), a mixed ionic-electronic conducting oxide, well known for its highly mobile oxygen interstitial ions, emerges as a potential switching material for novel L2NO4-based memristive devices. However, their integration in complementary metal oxide semiconductor (CMOS) technology still has to be demonstrated, as the major focus of previous studies has been carried out on epitaxial films grown on single crystals. In this work, we present the optimization of the deposition temperature and precursor solution composition, allowing to obtain high quality polycrystalline L2NO4 thin films grown by metal organic chemical vapour deposition on a platinized silicon substrate, and to use these films to build memristive devices in vertical configuration with Ti top electrodes. A bipolar analog-type transition in resistance can be achieved in Ti/L2NO4/Pt memristive devices. While the "forming" process required for the devices based on non-optimized L2NO4 thin films is considered as a drawback, the Ti/optimized L2NO4/Pt devices are forming-free and exhibit a good cyclability.These results prove the switching response of L2NO4-based devices in vertical configuration for the first time.

Epitaxial La0.5Sr0.5MnO3‐δ Bipolar Memristive Devices with Tunable and Stable Multilevel States

“…[3,10] On top of that, VCMs can be used for neuromorphic computing, where the device itself shows the behavior that is typically hardcoded in most AI applications, and hence, VCMs may present larger storage density and lower power consumption in applications such as those involving AI. [11][12][13] In our previous work, we studied pure LaMnO 3+δ , and proved that it was possible to change the resistance state up to two orders of magnitude by oxygen drift and by the concomitant redox reactions taking place at the materials' surface, as experimentally proven by combining conductive atomic force microscopy with X-ray photoemission electron spectroscopy Valence change memories are novel data storage devices in which the resistance is determined by a reversible redox reaction triggered by voltage. The oxygen content and mobility within the active materials of these devices play a crucial role in their performance.…”

“…The memristive properties of LSM50 are studied using titanium as an active electrode. As for other material combinations, [3,11,13,[33][34][35][36][37][38][39] the Ti/LSM50 stack can undergo a reversible redox reaction that originates two additional interlayers: oxidized metal electrode and oxygen-deficient oxide. The resistivity of both interlayers is higher than the parent compound.…”

“…[ 3,10 ] On top of that, VCMs can be used for neuromorphic computing, where the device itself shows the behavior that is typically hardcoded in most AI applications, and hence, VCMs may present larger storage density and lower power consumption in applications such as those involving AI. [ 11–13 ]…”

Analog memristive devices based on La2NiO4+ δ as synapses for spiking neural networks

“…Several studies reported on the VCM capabilities of memristive devices based on La 2 NiO 4+δ (L2NO4), a perovskite-related structure, using an ohmic Pt electrode and an active (i.e. easily oxidizable) Ti counter electrode (forming a rectifying and tunable Schottky contact) [38,39]. L2NO4 was selected as mixed ionic electronic conducting (MIEC) oxide due to its high oxygen mobility [40,41] able to facilitate the storage and exchange of oxygen with the active electrode material (Ti).…”

“…Recently, the previously mentioned L2NO4 planar memristive devices were successfully transferred to vertical Ti/L2NO4/Pt structures [39]. Nevertheless, these devices still presented certain cycle-to-cycle (c2c) and device-todevice (d2d) variability and resistance relaxation with time.…”