Forming-free, Uniform, and Multi-level Resistive Switching in W/AlO_xN_y/Al₂O₃/Pt Memristor by Nitrogen Annealing Strategy

By employing a nitrogen annealing strategy, we fabricated $\text{W} / \text{AlO}_{x} \ \text{N}_{y} / \text{Al}_{2} \text{O}_{3} / \text{Pt}$ bipolar memristor with a gradient distribution of nitrogen and oxygen concentrations. Annealing after deposition at $350{ }^{\circ} \text{C}$ introduces vacancies and repairs lattice damage, significantly enhancing device performance. The device demonstrates forming-free resistive switching behaviors with uniform cycle-to-cycle and device-to-device distributions, high endurance ($10^{8}$ cycles), robust retention ($3 \times 10^{3} \ \text{s} \text{@}$ RT and 350 K), and large memory window ($10^{4}$). Moreover, 3-bit resistance states programing positioning the device as a competitive candidate for neuromorphic computing applications. This nitrogen annealing strategy offers a low-cost and general approach to performance enhancement of other metal-oxide memristors.