R&D: Picosecond Multilevel Resistive Switching in Tantalum Oxide Thin Films

Nature Scientific Reports has published an article written by Ulrich Böttger, Moritz von Witzleben, Viktor Havel, Karsten Fleck, Institut für Werkstoffe der Elektrotechnik (IWE 2) and JARA – Fundamentals for Future Information Technology, RWTH Aachen University, 52056, Aachen, Germany, Vikas Rana, Peter Grünberg Institut PGI-10 and JARA – Fundamentals for Future Information Technology, Forschungszentrum Jülich, 52425, Jülich, Germany, Rainer Waser, Institut für Werkstoffe der Elektrotechnik (IWE 2) and JARA – Fundamentals for Future Information Technology, RWTH Aachen University, 52056, Aachen, Germany, and Peter Grünberg Institut PGI-7 and JARA – Fundamentals for Future Information Technology, Forschungszentrum Jülich, 52425, Jülich, Germany, and Stephan Menzel, Peter Grünberg Institut PGI-7 and JARA – Fundamentals for Future Information Technology, Forschungszentrum Jülich, 52425, Jülich, Germany.

Abstract: “The increasing demand for high-density data storage leads to an increasing interest in novel memory concepts with high scalability and the opportunity of storing multiple bits in one cell. A promising candidate is the redox-based resistive switch repositing the information in form of different resistance states. For reliable programming, the underlying physical parameters need to be understood. We reveal that the programmable resistance states are linked to internal series resistances and the fundamental nonlinear switching kinetics. The switching kinetics of Ta2O5-based cells was investigated in a wide range over 15 orders of magnitude from 105 s to 250 ps. The capacitive charging time of our device limits the direct observation of the set time below 770 ps, however, we found indication for an intrinsic switching speed of 10 ps at a stimulus of 3 V. On all time scales, multi-bit data storage capabilities were demonstrated. The elucidated link between fundamental material properties and multi-bit data storage paves the way for designing resistive switches for memory and neuromorphic applications.“