Ferroelectric and dielectric properties of sol–gel derived Ba xSr 1− xTiO 3 thin films

Abstract

Ferroelectric thin films of Ba 0.7Sr 0.3TiO 3, Ba 0.8Sr 0.2TiO 3, Ba 0.9Sr 0.1TiO 3 and BaTiO 3 were fabricated by a modified sol–gel technique on Pt/Ti/SiO 2/Si substrates. All the compositions crystallized in perovskite structure and consist of well-defined grains. As the value of x increases grain size of the Ba x Sr 1− x TiO 3 thin films increases while the dielectric permittivity decreases. Ba 0.7Sr 0.3TiO 3 composition possesses the highest dielectric permittivity of 748 (at 100 kHz). Hysteresis loops measured at room temperature for all compositions showed that BaTiO 3 has the largest remnant polarization of 4.8 μC/cm 2. The dielectric and ferroelectric properties of the sol–gel derived Ba x Sr 1− x TiO 3 thin films are strongly dependent on the Sr content and the grain size.