ALD-Assisted VO2 for Memristor Application

Vanadium dioxide (VO2) is a well-known candidate for memristor applications due to its insulator-to-metal transition (IMT) characteristics. The fabrication of memristor devices requires highly controlled synthesis processes concerning the material chemistry and geometry. Atomic layer deposition (ALD) offers unique advantages for the fabrication of hardware neural networks, such as miniaturization, conformality, and sub-nm thickness control. Herein, an ALD process for non-stoichiometric vanadium oxide (VOx) using tetrakis(dimethylamino)vanadium (TDMAV) and water as precursors is presented. Subsequently, a tailor-made annealing process converts VOx into VO2, which exhibits an IMT of about three orders of magnitude at around 70 degrees C, rendering it a promising memristor material. VO2 thin film and Si-Al2O3/VO2 core/shell memristors are fabricated and analyzed, both of which exhibited I-V hysteresis loops, indicating their suitability for memristor applications in both 2D and 3D morphologies. Additionally, these memristors are sensitive to the operation temperature, with the hysteresis loops narrowing and shifting toward lower voltages as temperature increases, eventually disappearing beyond VO2's intrinsic phase transition temperature. This study highlights the viability of ALD-assisted VO2 for memristor applications and demonstrates its potential for advancing the three-dimensionalization of neuromorphic chips.