Effect Of Thermal Stresses On The Dielectric Properties Of Strontium Titanate Thin Films

We develop a quantitative thermodynamic model to understand the role of thermal stresses on the dielectric permittivity and tunability of (001)-textured polycrystalline monodomain strontium titanate (SrTiO(3)) films. This methodology is used to compute the dielectric constant and tunability of SrTiO(3) films on Si, c-sapphire, LaAlO(3), and MgO substrates. Results show that dielectric properties of SrTiO(3) depend strongly on the growth/processing temperature T(G). For substrates such as MgO that induce compressive in-plane thermal stresses, the dielectric response of SrTiO(3) is enhanced. However, for SrTiO(3) films on IC-compatible substrates (Si and c-sapphire), thermal stresses can significantly degrade the dielectric permittivity and tunability. (C) 2011 American Institute of Physics. [doi:10.1063/1.3617430]