Current materials are being pushed to their physical limits in the quest for higher-density switches for computer storage and memory, leading to expanded research into “resistive switching” as the next standard form.

The basic idea involves an oxide - normally acting as an insulator - which can be transformed into a conductor by applying the appropriate electrical charge. A Resistive Random-Access Memory (R-RAM) device consisting of a single filament can be switched between two distinct resistance states (‘1’ and ‘0’) can be obtained through a simple process of filament rupture and re-formation.

Researchers in Singapore have tested a number of materials and indentified some good candidates for resistive switching. The most recent study found conductive nano-filaments in amorphous titanium dioxide (TiO2) thin-films could be used for resistive switching applications.

The results have been described in the journal AIP Advances by researchers Yuanmin Du, Andrew Thye Shen Wee and a team from the National University of Singapore and the Agency for Science, Technology and Research (A*STAR) of Singapore.

The team checked their results with a new combination of microscopy techniques; using Conductive Atomic Force Microscopy (CAFM) alongside Kelvin Probe Force Microscopy (KPFM) in a new filament-interface model, which could help guide the design of RRAM based devices.

The evidence of high density and uniformly distributed nano-filaments implies that high-density memory cells could be made using such oxide thin-films, which may show promise for a range of similar devices.

The small dimensions of the formed filament provides great advantages over current technology, as Prof Du explains: “in addition to TiO2, we believe that many other oxides could also have the similar properties.”

The study has been published online.