Structural and electrical properties of Pb(Zr,Ti)O ₃ thin films on GaN/Sapphire, Ru/Sapphire and Ru/GaN/Sapphire substrates

Lead zirconate titanate or Pb(Zr _0.3Ti _0.7)O ₃ thin films were deposited on GaN, Ru/Sapphire and Ru/GaN/Sapphire substrates by the sol-gel technique. The Ru films, with a (002) preferred orientation, were deposited by metalorganic chemical vapor deposition (MOCVD) on Sapphire (0001) and GaN/Sapphire substrates. The properties of PZT on Ru films, rapid thermal annealed under different conditions, are investigated. The P-E hysteresis curves and C-V data for PZT films on Ru/GaN and Ru/Sapphire substrates were measured as a function of voltage and frequency. The Metal-Ferroelectric-Semiconductor (MFS or Pt/PZT/GaN) structures, prepared by depositing PZT thin films on n-type (Si doping ∼1 × 10 ¹⁸ cm ^-3) and (0001)-GaN/Sapphire, were characterized for their dielectric properties. The PZT films on as-deposited Ru, as opposed to annealed Ru, exhibit improved properties; remnant polarization of 37 μC/cm ², dielectric permittivity of 425 at 100 KHz, and leakage current density ∼1 × 10 ^-7 A/cm ² at 1.5 V.