An XPS study and electrical properties of Pb1.1Zr0.53Ti0.47O3 /PbO/Si (MFIS) structures according to the substrate temperature of the PbO buffer layer

PbO and PZT thin films were deposited on the p-type (1 0 0) Si substrate by the rf magnetron sputtering method with PbO and Pb1.1Zr0.53Ti0.47O3 targets for the application of the metal–ferroelectric–insulator–semiconductor (MFIS) structure. The MFIS structures with the PbO buffer layer show the good electric properties including a high memory window and a low leakage current density. The maximum value of the memory window is 2.0 Vunder the applied voltage of 9 V for the Pt/PZT (200 nm, 400 8C)/PbO (80 nm)/Si structures with the PbO buffer layer deposited at the substrate temperature of 300 8C. From the X-ray photoelectron spectroscopy (XPS) results, we could confirm that the substrate temperature of PbO affects the chemical states of the interface between the PbO buffer layer and Si substrate, which results in the inter-diffusion of Pb and the formation of the intermediate phases (PbSiO3). And the existence of the undesired SiO2 layer, which is the low dielectric layer, was confirmed at the surface region of the Si substrate by the XPS depth profile analysis.