In this work, we give evidences of Ruddlesden-Popper (RP) phase formation in Pb(Zr,Ti)O₃ thin films deposited by multi-target reactive sputtering at a substrate temperature of 520C onto oxidized silicon wafers comprising a ZrO2 buffer layer. X-ray diffraction data of films deposited at 520C revealed the appearance of a Pb₂(Zr,Ti)O₄ RP phase. High-resolution transmission electron microscopy (HRTEM) images have proved the presence of a corresponding superstructure with a period of about 1.3 nm. It was nucleated on top of an amorphous, lead-enriched interface layer near the ZrO₂/PZT interface. At higher substrate temperatures, when this amorphous interface layer disappears, a perovskite structure with a sharp interface was nucleated directly on the ZrO₂ buffer layer.