Vertical 2T-nC FeRAM Demonstration: BEOL Read Transistor for 4F2 Memory Strings and Two-Terminal Selector Design for Polarization Disturb Mitigation

In this work, we demonstrate a vertical 2T-nC FeRAM with a back-end-of-line (BEOL) read transistor ($T_R$) for 4F2 string and propose a selector design to mitigate polarization disturb in passive capacitor crossbar arrays. Key contributions include: 1) successful integration and operationcomposed of a Si MOSFET write transistor ($T_W$), 3-layer cylindrical ferroelectric capacitors, and Si-doped $In_2O_3$ BEOL $T_R$, demonstrating the feasibility of 4F2 2T-nC string; 2) introducing nonlinearity into the capacitor stack to suppress ferroelectric voltage drop under inhibition biases while maintaining sufficient write voltage, reducing disturbance; 3)modeling and experimental validation of inserting a metal-semiconductor (a-Si)-metal (MSM) selector into the capacitor in mitigating the disturb, particularly achieving 9x reduction of disturb after $10^6$ cycles in the $V_W$/2 scheme.