Unified Steep-Slope Switching and Non-Volatile Memory in a Complementarily Stabilized van der Waals Ferroelectric Transistor.

Achieving both steep-slope switching and robust non-volatile memory within a single transistor would enable new device concepts for low-power and logic-in-memory architectures. Conventional negative-capacitance FETs (NC-FETs) are designed to suppress ferroelectric bistability to enable hysteresis-free sub-thermionic switching, whereas ferroelectric FETs (Fe-FETs) exploit bistable polarization to provide non-volatile memory, leaving the two operating regimes largely separate in practice. Here, we report a van der Waals ferroelectric negative-capacitance transistor (FeNC-FET) that simultaneously realizes stabilized negative capacitance and intrinsic bistable polarization by employing a CIPS/h-BN/α-In2Se3 trilayer gate stack. Landau-Khalatnikov analysis and polarization-voltage measurements confirm complementary ferroelectric roles in which CIPS provides static negative curvature, h-BN enables charge compensation, and α-In2Se3 supplies non-volatile polarization. This cooperative mechanism enables steep sub-threshold swings of 35 mV/dec (forward) and 51 mV/dec (reverse), a ∼3 V memory window, long retention (>104 s), and endurance exceeding 2500 cycles. The device further performs AND, OR, and majority logic-in-memory operations using 10 µs pulses with clear ON/OFF separation. These results establish the FeNC-FET as a compact platform that combines steep-slope switching with non-volatile programmability in a single device, enabling low-bias readout, short-pulse programming, and robust logic-in-memory operation.