Nonlinear and multilevel resistive switching memory in Ni/Si3N4/Al2O3/TiN structures

In this letter, we extensively investigate the nonlinear resistive switching characteristics of Si3N4-based resistive random access memory (RRAM) devices that contain an Al2O3 tunnel barrier layer to alleviate sneak path currents in the cross-point array structure. When the compliance current (ICC) exceeds 1 mA, the Ni/Si3N4/TiN device shows both unipolar and bipolar switching with Ohmic characteristics in the low resistance state. Nonlinear resistive switching characteristics were observed for this device when ICC was ≤100 μA. We fabricated Si3N4/Al2O3 bilayer devices with different tunnel barrier layer thickness and characterized their nonlinear characteristics and failure resistance during the reset process. Furthermore, we obtained stable multiple resistance levels in the devices by varying ICC and the stop voltage for the set and reset switching, respectively. Our results suggest that an Al2O3 tunnel barrier layer embedded in Si3N4-based RRAM devices offers considerable potential to realize high-density cross-point memory array applications.