Imaging Dielectric Breakdown in Valence Change Memory

Dielectric breakdown (DB) controls the failure, and increasingly function, of microelectronic devices. Standard imaging techniques, which generate contrast based on physical structure, struggle to visualize this electronic process. Here in situ scanning transmission electron microscopy (STEM) beam-induced current (EBIC) DB Pt/HfO2/Ti valence change memory devices is reported. STEM EBIC directly visualizes signatures DB, namely local changes conductivity electric field, with high spatial resolution good contrast. observed proceed through two distinct structures arranged series: a volatile, “soft” filament created by injection; non-volatile, “hard” oxygen-vacancy aggregation. This picture makes distinction between while at same time accommodating “progressive” where relative lengths hard soft filaments can continuum.