The thermal compatibility of fully sputtered, ferroelectric TiN/Hf _xZr _(1−x)O ₂/TiN thin-film capacitors with back-end-of-line processing is investigated. The sputtering power, ZrO ₂ concentration, and annealing temperature affect the crystal structure and ferroelectric properties of Hf _xZr _(1−x)O ₂ (HZO) in different ways, which is revealed by the grazing incidence X-ray diffraction and electric characterization. Moderate sputtering power and ZrO ₂ content favor the orthorhombic phase and higher remanent polarization. In contrast, low and high power or low and high ZrO ₂ concentrations increase the monoclinic and tetragonal/cubic phase fractions, respectively. For the first time, it is shown that annealing at 400 °C for 1 h can result in fully crystalline HZO films deposited by physical vapor deposition. Even pure HfO ₂ deposited from a 3 in. target with a sputtering power of 50 W exhibits some ferroelectric response after annealing at 400 °C and wakeup cycling.