Degradation and Recovery in HZO-Based FeFETs under Hydrogen and Thermal Stress for CMOS Integration

We investigated the degradation and recovery dynamics of Hf x Zr 1– x O 2 (HZO)-based ferroelectric field-effect transistors (FeFETs) under hydrogen contamination and thermal budgets, conditions relevant to advanced complementary metal-oxide-semiconductor (CMOS) processing, including back-end-of-line (BEOL) steps. High-pressure annealing (HPA) in a hydrogen-rich environment induced charge trapping and ferroelectric dipole pinning, leading to clockwise hysteresis and phase instability, as confirmed by electrical measurements and phase analysis. Subsequently, repeated program/erase cycling facilitated depinning, restoring polarization switching and partially recovering memory characteristics. These findings highlight the susceptibility of HZO to hydrogen-induced degradation in advanced integrations, such as monolithic 3D (M3D) with added hydrogen and thermal exposure. This underscores the need for hydrogen control and electric stress engineering to ensure reliable CMOS integration of FeFETs.