Ultralow‐Leakage‐Current and Filament‐Conductive Amorphous Germanium Selenide Nanoparticle Ovonic Threshold Switching Selectors

Both large-capacity storage and high-parallel computing demand a significant boost in integration density of memory chips at advanced technological nodes. This necessitates selector components in 3D stackable cross-point architectures to achieve an ultralow leakage current (I_off) and a relatively low threshold voltage (V_th). However, conventional ovonic threshold switching (OTS) selectors cannot optimize these two properties simultaneously due to their conflicting physical attributes. To overcome this challenge, we put forward an innovative material design of a thermally-robust amorphous Ge₂Se₃ nanoparticle (NP)-assembled nanolayer, by which the resulting selectors have achieved an unprecedentedly low I_off of ∼pA, an impressively high selectivity of ∼10⁸, a low V_th of ∼2.4 V, and commendable V_th reliability, outperforming existing OTS selectors. Through in situ off-axis electron holography characterizations, we have presented evidence of nanoscale filamentary conduction within the individual NPs, revealing subthreshold-conduction and switch-on behaviors that have hitherto not been directly observed. Our work will inspire further exploration of novel amorphous chalcogenide NPs and deeper research on filamentary conduction physics, advancing the pursuit of superior access performances in OTS selectors.