16-layer 3D Vertical RRAM with Low Read Latency (18ns), High Nonlinearity (>5000) and Ultra-low Leakage Current (~pA) Self-Selective Cells.

On-current and nonlinearity of selector-less RRAM are essential for improving the sensing speed and suppressing sneak path leakage respectively in 3D vertical crossbar structure. In this work, by using an oxide in which oxygen vacancies do not readily accumulate (NbO x ) to prepare the memory layer, 50x on-state current density improvement is achieved with high nonlinearity of 5000. The maximum nonlinearity of this device is even higher $(8 \times 10 ^{4}$ read @ 1.04 V). Furthermore, for the first time, we present a 16-layer 3D vertical RRAM. Other outstanding performances such as low off-current (~ pA), self-compliance and high endurance (> 10 ⁸ ) are also demonstrated.