TaO_x-based resistive switching memories: Prospective and challenges

Resistive switching memories (RRAMs) are attractive for replacement of conventional flash in the future. Although different switching materials have been reported; however, low-current operated devices (<100 μA) are necessary for productive RRAM applications. Therefore, TaO_x is one of the prospective switching materials because of two stable phases of TaO₂ and Ta₂O₅, which can also control the stable low- and high-resistance states. Long program/ erase endurance and data retention at high temperature under low-current operation are also reported in published literature. So far, bilayered TaO_x with inert electrodes (Pt and/or Ir) or single layer TaO_x with semi-reactive electrodes (W and Ti/W or Ta/Pt) is proposed for real RRAM applications. It is found that the memory characteristics at current compliance (CC) of 80 μA is acceptable for real application; however, data are becoming worst at CC of 10 μA. Therefore, it is very challenging to reduce the operation current (few microampere) of the RRAM devices. This study investigates the switching mode, mechanism, and performance of low-current operated TaO_x-based devices as compared to other RRAM devices. This topical review will not only help for application of TaO_x-based nanoscale RRAM devices but also encourage researcher to overcome the challenges in the future production.