Comparison of the Ferroelectricity for 70–80 nm Thick Pb(Zr,Ti)O₃ Films Deposited on (111)Ir Bottom Electrodes at Different Temperatures by MOCVD

Abstract

70–80 nm-thick Pb(Zr,Ti)O₃ (PZT) films were deposited on (111)Ir/TiO₂/SiO₂/Si substrates at 415 and 540°C by metalorganic chemical vapor deposition (MOCVD). The remanent polarization (P _r) value showed 22 μ C/cm² at an applied voltage of 3 V, even for the film deposited at 415°C. However, this value was almost 40% of that for the film deposited at the higher temperature. P _r value was enhanced up to 40 μ C/cm² and the squareness of the polarization-electric field (P-E) hysteresis loop was also improved by the post-annealing at 500°C, even though a noticeable change was not detected on the x-ray diffraction pattern. Moreover, both of the P _r and coercive field (E _c) values of the film annealed at 500°C after 415°C-deposition were almost saturated below 2 V, as same as the as-deposited films at 540°C.

Keywords:

• PZT
• MOCVD
• thickness scaling
• low deposition temperature