RF-wave induced CBRAM characteristic modulation specific to sheet-like conductive filaments

Abstract

The shape of conductive filaments in CBRAM is important for resistance switching and conductance modulation, especially in applications like neuromorphic and reservoir computing that use conductance as weight. We report on RF-induced modulation of CBRAM using Ge2Sb3.4Te6.2 with sheet-like filaments and compared it to those with dendritic filaments. RF input below 100 MHz reduced SET and RESET voltages, similar to CBRAM with dendritic filaments, but showed significantly different resistance changes. Repeated RF on/off input gradually increased the resistance of low-resistance state, unlike the dendritic filament CBRAM, where the resistance decreased. The increased resistance suggests RF-induced denser sheet-like filaments. Furthermore, the resistance of the high-resistance state showed a peculiar RF-induced resistance change not observed in dendritic filaments. The resistance decreased during RF input and increased to nine times the initial value when RF was switched off. The results show that the conductance modulation by RF input strongly depends on the filament type.