Sub-100-nA-operating Si-compatible Ni/Ti/HfO₂/SiO₂/Si RRAM device for high-density integration and low-power applications

In this study, we examined the switching behavior of a bipolar resistive random-access memory (RRAM) in a Ni/Ti/HfO₂/SiO₂/p⁺Si structure and its fabrication process for compatibility with complementary metal-oxide-semiconductor (CMOS). The HfO₂-based RRAM device embedding SiO₂ layer demonstrated ultra-low resistive switching of sub-100-nA. Also, more accurate models are proposed to explain the resistive switching and conduction mechanisms of the device. The SiO₂ reduces the switching current as a tunneling barrier and the HfO₂ layer plays a primary role in resistive switching by trapping and de-trappingby the electrons. Furthermore, a large number of switching cycles with low reset current (41.5-nA) were demonstrated from the results of DC endurance tests.