HfO_x-based vertical resistive switching random access memory suitable for bit-cost-effective three-dimensional cross-point architecture

The three-dimensional (3D) cross-point array architecture is attractive for future ultra-high-density nonvolatile memory application. A bit-cost-effective technology path toward the 3D integration that requires only one critical lithography step or mask for reducing the bit-cost is demonstrated in this work. A double-layer HfO_x-based vertical resistive switching random access memory (RRAM) is fabricated and characterized. The HfO_x thin film is deposited at the sidewall of the predefined trench by atomic layer deposition, forming a vertical memory structure. Electrode/oxide interface engineering with a TiON interfacial layer results in nonlinear I-V suitable for the selectorless array. The fabricated HfO_x vertical RRAM shows excellent performances such as reset current (<50 μA), switching speed (<100 ns), switching endurance (>10⁸ cycles), read disturbance immunity (>10 ⁹ cycles), and data retention time (>10⁵ s @ 125 C).