Experimental study of resistive bistability in metal oxide junctions

We have studied resistive bistability (memory) effects in junctions based on metal oxides, with a focus on sample-to-sample reproducibility, which is necessary for the use of such junctions as crosspoint devices of hybrid CMOS/nanoelectronic circuits. Few-nm-thick layers of NbO x , CuO x and TiO x have been formed by thermal and plasma oxidation, at various deposition and oxidation conditions, both with and without rapid thermal post-annealing. The resistive bistability effect has been observed for all these materials, with particularly high endurance (over 10 3 switching cycles) obtained for single-layer TiO 2 junctions, and the best reproducibility reached for multi-layer junctions of the same material. Fabrication optimization has allowed us to improve the OFF/ON resistance ratio to about 10 3 , but the sample-to-sample reproducibility is so far lower than that required for large-scale integration.