Ferroelectric-Driven Nonvolatile Phase Transition in MoTe<sub>2</sub> Transistors With an Expanded Memory Window.
basic_science · Level V
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- Record sourced from PubMed, PMID 42755246.
- Also identified by DOI 10.1002/adma.75046.
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Abstract
Polymorphic MoTe<sub>2</sub> offers a unique opportunity for phase-transition memristors due to its reversible structural transitions between semiconducting (2H) and metallic (1T') phases. Although gate-tunable phase transitions have been demonstrated, the presence of mobile ions in electrolyte gating leads to volatile behavior. Here, we demonstrate a phase-transition ferroelectric field-effect transistor (PT-FeFET) employing a polymorphic MoTe<sub>2</sub> channel and a Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> (HZO) ferroelectric gate insulator. The ferroelectric polarization of the HZO layer induces an electrically driven, long-term nonvolatile phase transition in the MoTe<sub>2</sub> channel. Unlike conventional FeFETs, in which the memory window is confined between the SET and RESET threshold voltages (V<sub>th</sub>), the 1T' metallic phase in the MoTe<sub>2</sub> PT-FeFET eliminates the OFF state and the corresponding SET V<sub>th</sub>, thereby enabling expansion of the memory window across the entire voltage range below the RESET V<sub>th</sub>. Consequently, the device exhibits both a wide memory window (82.5%) and a high ON/OFF current ratio (10<sup>6</sup>), outperforming conventional FeFETs. Owing to its wide memory window, the PT-FeFET accesses the full spectrum of synaptic weights (0-1) with near-ideal linearity (β = 0.9). As a result, the PT-FeFET achieves 82% accuracy in CIFAR-10 classification, surpassing the 59%-75% accuracy of conventional FeFETs.