Improvement of Quality and Electrical Properties of Sputtered Pb(Zr, Ti)O3 Films by Wet-Oxidation Process

A wet-oxidation process was proposed to improve the quality and electrical properties of Pb(Zr,Ti)O-3 (PZT) thin films prepared by the RF-magnetron sputtering technique. For the oxidation of metallic Pb in as-deposited PZT films, the wet-oxidation process was carried out using hydrogen peroxide solutions prior to postannealing for crystallization. In the case of PZT films on Pt/Ti/SiO2/Si substrates, the density of defects observed using an optical microscope was drastically decreased by means of the wet-oxidation process, and the shape of polarization vs voltage hysteresis loops of PZT films was also improved. In the case of PZT films on Pt/IrO2/SiO2/Si substrates, microvoids were diminished by means of the wet-oxidation process. For 70 nm-thick PZT films on Pt/IrO2/SiO2/Si substrates, hysteresis loops could not be measured without the wet-oxidation process. However, the films with the wet-oxidation process exhibited the slim-type hysteresis loop with a remanent polarization of over 23 mu C/cm(2) even at 2 V and a coercive voltage of about 0.7 V.