Annealing-modulated ferroelectricity and leakage suppression in PLD-grown Gd-doped HfO2 thin films with TiN top electrodes

HfO 2 -based ferroelectric thin films have emerged as promising candidates for next-generation non-volatile memory devices because of their nanoscale ferroelectricity and compatibility with complementary metal-oxide-semiconductor technology. However, stabilizing the metastable ferroelectric orthorhombic phase while maintaining low leakage current remains a central challenge, particularly for films prepared by physical deposition routes. Here, we report pulsed-laser-deposited Hf 0.97 Gd 0.03 O 2 thin films integrated with TiN top electrodes and investigate the correlation among phase structure, chemical state, processing sequence, film thickness, and ferroelectric properties. X-ray diffraction and high-resolution transmission electron microscopy reveal the coexistence of orthorhombic and monoclinic phases, with lattice fringes corresponding to the orthorhombic (111) plane confirming the presence of the ferroelectric phase. X-ray photoelectron spectroscopy verifies Hf 4+ and Gd 3+ chemical states and reveals a defect-related oxygen component. The final TiN-integration/N 2 post-annealing process is associated with the emergence of clear ferroelectric switching and a leakage-current density of 2.69 × 10 −8 A cm −2 at −5 V, approximately four orders of magnitude lower than that reported for the oxygen-treated control in the initial dataset. The remanent polarization increases with film thickness, reaching approximately 33 μC cm −2 for the 20-nm-thick film. The existing 10-nm-thick endurance data show measurable cycling endurance but pronounced degradation beyond approximately 10 6 cycles, rather than stable long-term endurance. These results establish a processing-structure-property framework for PLD-grown Gd-doped HfO 2 thin films and identify electrode/post-annealing integration, phase constitution, interfacial electrostatics, and defect-related oxygen chemistry as coupled variables that require joint consideration for microelectronic applications.