Resistive Random Access Memory Filament Visualization and Characterization Using Photon Emission Microscopy

Near InfraRed (NIR) photon emission is observed from filaments in HfO2 Resistive Random Access Memories (ReRAMs). This technique is non-destructive and offers rapid localization of filaments, enabling statistical analysis of their spatial distribution. We show that the emission is electric-field driven. We also report direct experimental evidence of ${i}$ ) completely random spatial distribution of filaments across multiple devices and ii) formation of multiple filaments inside a single large device.