HfOx-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 HfOx-based vertical resistive switching random access memory (RRAM) is fabricated and characterized. The HfOx 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 HfOx vertical RRAM shows excellent performances such as reset current (<50 μA), switching speed (<100 ns), switching endurance (>10(8) cycles), read disturbance immunity (>10(9) cycles), and data retention time (>10(5) s @ 125 °C).