Pt/PZT/PbO/Si with the MFIS structure was deposited on the p-type (100) Si substrate by the r.f. magnetron sputtering method with Pb1.1Zr0.53Ti0.47O3 and PbO targets. From the X-ray photoelectron spectroscopy (XPS) results, we could confirm that the partial pressure ratio during PbO deposition affects the interface condition of PbO/Si and the chemical state of Pb existing at the surface of the PZT thin film. The maximum value of the memory window is 3.0 V under the applied voltage of 9V for Pt/PZT (200 nm 400°C)/PbO (80 nm, 300°C)/Si structures with the PbO buffer layer deposited at the partial pressure of 7:3. From these results, we could assume that the PbO buffer layers play a role of the diffusion barrier between the PZT thin film and the Si substrate as well as the seed layer.