On-device cryogenic quenching enables robust amorphous tellurium for threshold switching

Amorphous chalcogenide alloys exhibiting crystallization-free Ovonic threshold switching behaviour have gained immense attention as selector materials. While the switching characteristics depend on the chalcogen species, understanding device-level elemental behaviour, particularly for tellurium (Te), remains challenging due to its low crystallization temperature and poor glass-forming ability. Here, we realize an electrothermally induced amorphous Te (a-Te) phase via on-device cryogenic quenching, which rapidly suppresses crystallization in the supercooled liquid at low ambient temperature. The order-to-disorder transition yields a ~ 0.81 V increase in threshold voltage and a ~ 10³ reduction in subthreshold current, attributed to enhanced deep-level trap formation. The a-Te phase exhibits reliable self-regulated oscillations, driven by deep traps, distinguishing it from conventional capacitance-driven effects. These findings support that the threshold switching in Te originates from defect-mediated transitions occurring before melting, rather than solely from thermal phase-change effects. Our results provide insights into chalcogenide switching mechanisms and pave the way for stoichiometry-tuned selector devices, nano-oscillators, and selector-only memory applications.