Performance Optimization for Ferroelectric HfZrO_x on a Ge Substrate by Modifying the Deposition Temperature

Hafnia ferroelectric-based Fe-FET devices have attracted increasing interest due to their CMOS compatibility, high scalability and low power consumption. Ge-based Fe-FETs could help overcome the shortcomings of Si-based Fe-FETs caused by the interface layer. In this work, the effect of the deposition temperature on the TiN/Hf_0.5Zr_0.5O₂/Ge device performance is systematically studied, which is helpful for finding the optimal conditions for Ge-based Fe-FETs. By adjusting the deposition temperature, the endurance property of the MFS capacitor is successfully enhanced to 2×10⁵ cycles with a large minimum remnant polarization (2P_r ≈ 46 μC/cm²). The observed phenomenon could be well understood by the effects of the deposition temperature and impurity concentration on the grain size.