This study investigates the enhanced polarization switching characteristics of HfO₂ ultrathin films through acceptor-donor co-doping. HfO₂-based ferroelectrics are promising for ferroelectric memory applications due to their CMOS compatibility and scalability, but their polarization switching performance lags behind perovskite ferroelectrics. Defects in HfO₂ play a critical role in stabilizing the metastable polar phase, but they also hinder domain wall motion and slow down switching. To address this, the authors propose a co-doping strategy using La³⁺ (acceptor) and Ta⁵⁺ (donor) to improve ferroelectric properties and switching speed. The co-doped HfO₂ films exhibit significantly enhanced ferroelectricity and the fastest switching process reported among HfO₂-based devices. The films maintain robust macro-electrical characteristics even at a thickness as low as 3 nm, expanding their potential applications in ultrathin devices. Systematic investigations show that the co-doping strategy reduces defects, improves microstructure, and lowers the switching barrier, leading to enhanced polarization and faster switching. Structural and defect state characterizations reveal that co-doped HfO₂ films have a more uniform microstructure and reduced defects compared to La-doped or Ta-doped films. X-ray absorption spectroscopy (XAS) and X-ray linear dichroism (XLD) studies indicate that co-doping enhances oxygen polyhedral distortion, contributing to improved polarization. Pole figure measurements and STEM imaging confirm the presence of multiple domain variants and a more uniform microstructure in co-doped films. Electrical measurements show that co-doped HfO₂ films have higher remnant polarization, lower coercive fields, and faster switching dynamics compared to La-doped films. Switching kinetics were analyzed using pulse switching measurements, revealing that co-doped films exhibit significantly faster switching times. The switching mechanism was modeled using the nucleation limited switching (NLS) and Kolmogorov-Avrami-Ishibashi (KAI) models, with the KAI model fitting the co-doped films better. First-principles calculations reveal that co-doping reduces the energy of the intermediate state and lowers the switching barrier, enhancing polarization switching. The co-doping strategy effectively mitigates the adverse effects of charged oxygen vacancies, leading to improved ferroelectric properties and faster switching. The results demonstrate that co-doping is an effective method to enhance the switching behavior of HfO₂ thin films, enabling their use in advanced ultrathin devices.This study investigates the enhanced polarization switching characteristics of HfO₂ ultrathin films through acceptor-donor co-doping. HfO₂-based ferroelectrics are promising for ferroelectric memory applications due to their CMOS compatibility and scalability, but their polarization switching performance lags behind perovskite ferroelectrics. Defects in HfO₂ play a critical role in stabilizing the metastable polar phase, but they also hinder domain wall motion and slow down switching. To address this, the authors propose a co-doping strategy using La³⁺ (acceptor) and Ta⁵⁺ (donor) to improve ferroelectric properties and switching speed. The co-doped HfO₂ films exhibit significantly enhanced ferroelectricity and the fastest switching process reported among HfO₂-based devices. The films maintain robust macro-electrical characteristics even at a thickness as low as 3 nm, expanding their potential applications in ultrathin devices. Systematic investigations show that the co-doping strategy reduces defects, improves microstructure, and lowers the switching barrier, leading to enhanced polarization and faster switching. Structural and defect state characterizations reveal that co-doped HfO₂ films have a more uniform microstructure and reduced defects compared to La-doped or Ta-doped films. X-ray absorption spectroscopy (XAS) and X-ray linear dichroism (XLD) studies indicate that co-doping enhances oxygen polyhedral distortion, contributing to improved polarization. Pole figure measurements and STEM imaging confirm the presence of multiple domain variants and a more uniform microstructure in co-doped films. Electrical measurements show that co-doped HfO₂ films have higher remnant polarization, lower coercive fields, and faster switching dynamics compared to La-doped films. Switching kinetics were analyzed using pulse switching measurements, revealing that co-doped films exhibit significantly faster switching times. The switching mechanism was modeled using the nucleation limited switching (NLS) and Kolmogorov-Avrami-Ishibashi (KAI) models, with the KAI model fitting the co-doped films better. First-principles calculations reveal that co-doping reduces the energy of the intermediate state and lowers the switching barrier, enhancing polarization switching. The co-doping strategy effectively mitigates the adverse effects of charged oxygen vacancies, leading to improved ferroelectric properties and faster switching. The results demonstrate that co-doping is an effective method to enhance the switching behavior of HfO₂ thin films, enabling their use in advanced ultrathin devices.