Mar 28, 2012
Controlled quantum conductance in resistive switches highlights opportunity for atomic-scale memory
As conventional Flash memory approaches the downscaling limit, developers are considering alternative technologies that will satisfy future devices. Recently, non-volatile resistive switches based on nano-ionic redox phenomena have attracted much attention as a potential candidate. Benefits include low power consumption, fast switching and high scalability. Now, researchers from RWTH Aachen University and Forschungszentrum Jülich have observed the controllable quantum conductance of a nanosized metallic filament within a solid electrolyte, raising the prospect of atomic-scale memory.
The team studied the resistive switching effect in silver iodide, a well known silver ion conductor. The scientists fabricated simple microscale crossbars consisting of silver iodide sandwiched between two metal electrodes.
The electrical resistance of their memory cells was controlled by voltage and current signals with pulse lengths down to 50 ns. While conventional memory cells can only store a single bit (ON or OFF), resistive switches have the potential of storing multiple bit information in a single cell.
The researchers observed at least five quantized resistances within a current window of 1–10 µA, which fitted well to an integer multiple of single atomic point contact conductivity.
Additional details can be found in the journal Nanotechnology.
About the author
The study was conducted by the Electronic Materials Research Lab (EMRL), a collaboration of researchers at the RWTH Aachen University and Forschungszentrum Jülich. Both teams are headed by Prof. Rainer Waser, and are members of the section Fundamentals of Future Information Technology of the Jülich Aachen Research Alliance (JARA-FIT). Stefan Tappertzhofen is a PhD student in electronic engineering at the RWTH Aachen University. He fabricated the memory devices and performed the measurements. Dr Ilia Valov and Prof. Waser contributed to the work at all stages.