Low Voltage Operating 2D MoS₂ Ferroelectric Memory Transistor with Hf_1-xZr_xO₂ Gate Structure

Ferroelectric field effect transistor (FeFET) emerges as an intriguing non-volatile memory technology due to its promising operating speed and endurance. However, flipping the polarization requires a high voltage compared with that of reading, impinging the power consumption of writing a cell. Here, we report a CMOS compatible FeFET cell with low operating voltage. We engineer the ferroelectric Hf_1-xZr_xO₂ (HZO) thin film to form negative capacitance (NC) gate dielectrics, which generates a counterclock hysteresis loop of polarization domain in the few-layered molybdenum disulfide (MoS₂) FeFET. The unstabilized negative capacitor inherently supports subthermionic swing rate and thus enables switching the ferroelectric polarization with the hysteresis window much less than half of the operating voltage. The FeFET shows a high on/off current ratio of more than 10⁷ and a counterclockwise memory window (MW) of 0.1 V at a miminum program (P)/erase (E) voltage of 3 V. Robust endurance (10³ cycles) and retention (10⁴ s) properties are also demonstrated. Our results demonstrate that the HZO/MoS₂ ferroelectric memory transistor can achieve new opportunities in size- and voltage-scalable non-volatile memory applications.