RECENT PROGRESS IN SPUTTERING PZT THIN-FILMS FOR FERROELECTRIC MEMORIES

This paper describes amorphous Pb(Zr, Ti)O-3 (PZT) thin films deposite d by cosputtering Pb(Zr0.5Ti0.5)O-3 and PbO targets. By optimizing the amount of the excess ph and the deposition temperature, PZT thin film s with a single perovskite phase were obtained successfully on Ir subs trates and Pt substrates at 520 degrees C. 250-nm-thick PZT films crys tallized by rapid thermal annealing (RTA) at 600 degrees C for 20 s ex hibited excellent ferroelectric properties: a coercive voltage of 1.0 V, a remanent polarization density of about 40 mu C/cm(2), and a polar ization switching endurance over 1x10(9) cycles. Although a heat treat ment in a reductive ambient causes degradation of ferroelectric proper ties of PZT thin films, their degraded ferroelectric properties can be easily recovered from by a 1-min RTA in an oxygen at 400 degrees C.