STUDY OF ELECTRICAL-PROPERTIES OF PULSED EXCIMER-LASER DEPOSITED STRONTIUM-TITANATE FILMS

Polycrystalline SrTiO3 films were prepared by pulsed excimer laser abl ation on Si and Pt coated Si substrates. Several growth parameters wer e varied including ablation fluence, pressure, and substrate temperatu re. The structural studies indicated the presence of [100] and [110] o riented growth after annealing by rapid thermal annealing at 600-degre es-C for 60 s. Deposition at either lower pressures or at higher energ y densities encouraged film growth with slightly preferred orientation . The scanning electron microscopy studies showed the absence of any s ignificant particulates on the film surface. Dielectric studies indica ted a dielectric constant of 225, a capacitance density of 3.2 fF/mum2 , and a charge density of 40 fC/mum for films of 1000 nm thick. The dc conductivity studies on these films suggested a bulk limited space ch arge conduction in the high field regime, while the low electric field s induced an ohmic conduction. Brief time dependent dielectric breakdo wn studies on these films, under a field of 250 kV/cm for 2 h, did not exhibit any breakdown, indicating good dielectric strength.