Beyond CMOS and RF devices, integrated circuits and technologies

Non-volatile, reconfigurable resistance switches

© Fraunhofer ENAS
Scanning electron microscopy image of the surface of a BiFeO3 film in a BiFeO3-resistance switch with Bit line (T1) and Word line (T2) and schematic respresentation of possible applications of non-volatile, reconfigurable resistance switches.

The thriving of memristive oxide switches is arousing interest in the field-enhanced hopping transport of oxygen vacancies because memristive oxide switches exhibit ultra-nonlinear switching dynamics. Optimized performance requires resistive switching (SET and RESET) within tens of nanoseconds upon the application of a writing bias, and the ON and OFF resistance states should remain stable for up to ten years.

Field-accelerated ion mobility constitutes one such source of ultra-nonlinearity. The Mott-Gurney has been employed nonlinear ionic drift model to interpret the effect of an electric field on the nonlinear rate of ion transport in a memristive Au/BiFeO3/Pt/Ti metal-oxide-metal switch using a quasistatic statetest protocol. Memristive bismuth iron oxide (BFO) switches possess excellent bipolar switching performance, including long retention time and stable endurance even at elevated temperatures. Furthermore, due to the interface-mediated resistive switching, memristive BFO switches reveal zero Joule heating and electroforming-free resistive switching.
Thus, the measured increase in mobility of oxygen vacancies can be attributed unambiguously to the field enhancement rather than to temperature enhancement.