Low Voltage Operating 2D MoS Ferroelectric Memory Transistor with HfZrO 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 HfZrO (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 (MoS) 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 10 and a counterclockwise memory window (MW) of 0.1 V at a miminum program (P)/erase (E) voltage of 3 V. Robust endurance (10 cycles) and retention (10 s) properties are also demonstrated. Our results demonstrate that the HZO/MoS ferroelectric memory transistor can achieve new opportunities in size- and voltage-scalable non-volatile memory applications.