Electrical characterization of SrTiO3 thin films deposited on Si(001) substrate by liquid injection MOCVD

The electrical properties of SrTiO3 thin films grown on Si substrates by liquid injection MOCVD have been investigated as a function of films thickness (from 4 to 200 nm). Using an heterometallic precursor and optimised low pressure conditions, highly textured SrTiO3 films were obtained in a 30-150 nm thickness range. A continuous increase of the SrTiO3 dielectric permittivity with increasing films thickness is deduced, and an interface state density minimum value, lower than 1 × 1011 cm-2 eV-1 is observed for 30 nm films. The lowest gate current is obtained for 30-50 nm films: in those samples, the conduction is identified as a Schottky emission type mechanism. For thinner films, the gate current increases when the thickness decreases as classically observed for amorphous oxides. For thicker samples, the leakage current is enhanced by the polycrystalline microstructure of the SrTiO3 films.