Reconfigurable impedance in memristive devices

Abstract

Memristors have been a prospering topic in nanoelectronics research for the last decade. Their attributes have been diligently studied by multiple research groups and multiple applications that leverage their state-dependent programmability in a static fashion, have appeared. Practical applications of memristor-based AC circuits have been rather sparse, with only a few examples found in the literature where their use is only emulated. In this work a methodology is presented, which can be used to characterise memristive impedance. Using the developed methodology, the behaviour of metal-oxide memristors under a non-invasive AC perturbation is studied. Metal-oxide memristors are found to behave as RC low-pass filters and they present a variable cut-of frequency when their state is switched, thus providing a window of reconfigurability when used as filters. This window of reconfigurability can be engineered by changing the geometrical properties of the devices. Multiple material combinations have been tested to ascertain the best working device to use in the future. The most promising stack has been electrically and physically characterised to understand the reason behind its superiority against other combinations and to use that knowledge to actively fabricate better devices. Making use of findings from this study, concerning device AC and DC behaviour, a new 3-terminal configuration is fabricated and characterised. It is found to be able to form in both serial and antiserial connection of constituent memristive devices. This new stack is found to allow fine tuning of states, through a coarse/fine tuning arrangement of constituent devices, and an increased state density due to the combination of allowed states. In this case AC behaviour is similar to single device stacks, with both devices contributing to the cut-of frequency. This study extends current knowledge on metal-oxide memristors by characterising their frequency dependent characteristics, as well as their DC characteristics, and providing useful insights for their use in reconfigurable AC circuits.

More information

Identifiers

ORCID for Spyridon Stathopoulos: orcid.org/0000-0002-0833-6209

Catalogue record

Export record