La2NiO4+δ‐Based Memristive Devices Integrated on Si‐Based Substrates

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, the optimization of the deposition temperature and precursor solution composition is presented, allowing to obtain high‐quality polycrystalline L2NO4 thin films grown by metal organic chemical vapor 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 nonoptimized 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 a vertical configuration for the first time. The growth of high‐quality La2NiO4+δ (L2NO4) is achieved by PI‐MOCVD, in which the deposition temperature and film composition are easily tuned. When L2NO4 is used as a sandwiched layer in a memristive device, analogue transitions in the SET and RESET processes are obtained. While Ti/non‐optimized L2NO4/Pt devices require a ‘forming’ step, Ti/optimized L2NO4/Pt devices are forming‐free and have good endurance.