Fully CMOS-Compatible 1T1R Integration of Vertical Nanopillar GAA Transistor and Oxide-Based RRAM Cell for High-Density Nonvolatile Memory Application

A fully CMOS-compatible vertical nanopillar gate-all-around transistor integrated with a transition-oxide-based resistive random access memory cell to realize 4F² footprint has been demonstrated and systematically characterized. The nanopillar transistor exhibits excellent transfer characteristics with diameter scaled down to a few tens of nanometer. Three types of resistive switching behavior have been observed in the fabricated one-transistor one-resistor cell, namely, preforming ultralow-current switching, unipolar switching, and bipolar switching after forming process. A reset current of only 200 pA has been observed in the preforming ultralow-current switching, while for the unipolar and bipolar switching modes after forming process, good memory performance and operation parameter uniformity are demonstrated. Furthermore, reset current is found to decrease with reducing nanopillar transistor design diameter, which is beneficial for circuit power consumption consideration.