PZT films by the mod technology for non-volatile memory and dram applications

Abstract

Ferroelectric Pb(Zr_1-xTi_x)O₃ (PZT) films that were nearly pin hole free with uniform composition and thickness were synthesized using the metallo-organic decomposition technology. Experimental results show that the crystal structure and electrical properties of these PZT films depend strongly on the processing parameters, such as pyrolysing temperature, spinning speed, and annealing conditions. The polarization reversal characteristics and fatigue behaviour which are important for the non-volatile memory applications were studied. By optimizing the annealing conditions, a 60/40 PZT film exhibited a dielectric strength of 1 MV/cm and a sensed remanent polarization value of 9.3 μC/cm² after cycling 10¹⁰ times, showing good promising of PZT films for non-volatile memory applications. The high values of dielectric constant for these PZT films, about 600 to 2000, were 150 to 500 times larger than that of currently used dielectric SiO₂ in DRAM. This fact suggests that PZT film is a natural choice for the new generation, extreme high density DRAM's application.