SrTiO3 thin film capacitors on silicon substrates with insignificant interfacial passive layers

Using sputter deposition, nonepitaxial ultrathin film capacitors consisting of SrRuO3 electrodes and dielectric SrTiO3 (STO) were grown directly on oxidized silicon substrates. The surface roughness of the layers was found to be very low (≲0.2 nm). Dielectric measurements as a function of temperature were performed on samples with different STO thickness down to 7 nm, showing temperature dependence of the interfacial passive layers. The dielectric constant of the STO films was found to be in the range of 200 at room temperature for all samples, which leads to a minimum capacitance equivalent thickness below 0.2 nm.