PZT thin films were fabricated on Pt/Ti/SiO2/Si substrates at 500℃ by ECR-PECVD for the application to the charge storage capacitor of ULSI DRAMs. Perovskite single phase PZT films were obtained by controling the film compositional ratio Pb/(Zr+Ti) close to 1. The anion concentrations in the PZT films were successfully controlled by adjusting the flow rates of each MO sources. Capacitance of a typical 94 nm thick PZT film prepared at 500℃ in this work was about 5.3 uF/cm², which corresponds to the equivalent SiO2 thickness of 0.65nm.