Real time observation of nanoscale multiple conductive filaments in RRAM by using advanced in-situ TEM

In this letter, we dynamically investigate the resistive switching characteristics and physical mechanism of the ZrO₂-based device. Using in-situ transmission electron microscopy, we observe in real time that multiple conductive filaments (CFs) are formed across the ZrO₂ layer between top electrode and bottom electrodes after forming. Various top electrode materials have been used, such as Cu, Ag, and Ni. Contrary to common belief, it is found that CF growth begins at the anode, rather than having to reach the cathode and grow backwards. Energy-dispersive X-ray spectroscopy results confirm that metal from the top electrode is the main composition of the CFs.