Physical mechanism of HfO2-based bipolar resistive random access memory

The (anode) TiN/Ti/HfO
2
/TiN (cathode) resistive random access memory (RRAM) (Fig. 1) has shown yield ∼ 100% [1]. Its simple metal-insulator-metal (MIM) structure exhibits great potential for an embedded BEOL memory compatible with the high-k/metal gate CMOS process. There have been many theories of RRAM physical mechanism in the literature. This paper focuses on HfO
2
-based RRAM and describes a complete physical mechanism from forming, SET/RESET, current conduction, to explanations of various observed phenomena including multilevel, cell size scaling, resistance fluctuation, soft error, and non-abrupt RESRT process. Finally, suggestions for device optimization are given based on the physical model.