Ultra-thin fatigue free lead zirconate titanate thin films for gigabit DRAMs

Thin films of Pb-based ferroelectric materials have attracted much attention because of the potential use as the dielectric in the storage capacitors of 1 Gb DRAMs. Sputtering, sol-gel, pulsed laser deposition, and metal organic chemical vapor deposition are widely used for ferroelectric film preparation; but there have been few reports using vacuum evaporation. This may be because lead has a low affinity for oxygen and high volatility. We can overcome these problems by employing high-concentration ozone. The thickness scaling of ferroelectric lead zirconate titanate (PZT) thin films by reactive evaporation is investigated.