Ferroelectric properties of strontium-bismuth tantalate thin film deposited by RF magnetron sputtering method

Characteristics of ferroelectric thin films of strontium-bismuth tantalate (SBT), which were deposited by means of HF magnetron sputtering on Pt/TiO$_2$/SiO$_2$/Si substrates, are investigated. The dependences of permittivity, residual polarization, and coercitivity of SBT films on the modes of subsequent annealing are established. Films with the residual polarization of $2P_r = 3.02$ $\mu$C/cm$^2$ and coercitivity of $2E_c = 140$ kV/cm are obtained at the annealing temperature of $800^\circ$ C. The dielectric constant and loss tangent at the frequency of $1.0$ MHz were accordingly equal to $\varepsilon = 125$ and $\mathrm{tg}\,\delta = 0.067$. The Curie temperature of the films reached $310$–$315^\circ$ C.