Transient thermometry and HRTEM analysis of RRAM thermal dynamics during switching and failure

We investigate RRAM thermal dynamics during resistive switching and endurance failure by using transient thermometry and HRTEM analysis. The filament size was estimated to ~1 nm with 7-15 nm crystalline region, having experienced local temperatures of > 1600 K at the filament core and > 850 K in the heat affected zone. The devices that underwent cold switching show no change in the HfAlO_x microstructure, post-programming. However, such devices show preferential templated growth of HfAlOx crystallite, extending from the polycrystalline Hf layer after 10⁷ switching cycles, eventually culminating in a RESET failure.