Dielectric properties and Schottky barriers in silver tantalate-niobate thin film capacitors

Submicron thick ferroelectric Ag(Ta,Nb)O-3 films have been pulsed laser deposited on the bulk Pt80Ir20 polycrystalline substrates. They are ferroelectric at temperatures below 125 K with the remnant polarization of 0.4 muC/cm(2) @ 77K and paraelectric at higher temperatures with tandelta @ 100 kHz as low as 0.015. Extensive I-V characterization has been performed in a wide temperature range 77 K to 350 K for vertical Me/Ag(Ta,Nb)O-3/Pt80Ir20 capacitive cells, where the metals Me = Pd, Au, Cr, and Al have been used as a top electrode. The electronic transport in thin Me/Ag(Ta,Nb)O-3/Pt80Ir20 capacitors follows the Schottky emission mechanism with the barrier height for the Pd, Au, Cr, and Al of 0.85, 0.8, 0.74, and 0.69 eV, respectively.
QC 20100525