Investigation of oxygen deficiency-rich/oxygen deficiency-poor stacked TiO2 based resistive random access memory by mist chemical vapor deposition.

The oxygen deficiency-rich TiO 2 /oxygen deficiency-poor TiO 2 stacking structure grown by mist chemical vapor deposition method is used as resistive switching layers of resistive random access memory. Three different annealing temperatures of 500, 600, and 700oC are used to grow the oxygen deficiency-poor TiO 2. The experimental results indicate that the resistances of the oxygen deficiency-rich TiO 2 /oxygen deficiency-poor TiO 2 and the single-layer TiO 2 resistive random access memories are switchable by forming and rupturing the filament paths which are composed of oxygen deficiencies. The number of the filament paths is limited by the oxygen deficiency-poor TiO 2 layer, which improves the memory window and endurance of the resistive random access memory. The stacked structure with the oxygen deficiency-poor TiO 2 which is annealed at 600oC has the largest memory window of 7.8 × 105, endurable switching operation (>103 voltage loops), and long retention time (>104 s). In addition, the current conduction mechanism at the high resistance state of the RRAM with the stacked structure as the resistive switching layer is different from the one using the as-deposited TiO 2 as the resistive switching layer. [ABSTRACT FROM AUTHOR]