Excimer laser ablated barium strontium titanate thin films for dynamic random access memory applications

Polycrystalline thin films of Ba0.5Sr0.5TiO3 were deposited by excimer laser (248 nm) ablation. Films deposited near 575° C exhibited good crystallinity, a dielectric constant of 330, a dissipation factor of 0.02, a leakage current density of 2×10-7 A/cm2, a charge storage density of 36 fC/µm2, and breakdown time of 3700 s at an applied electric field of 0.125 MV/cm. The C-V (capacitance-voltage) behavior of both MFM (metal-ferroelectric-metal) and MFS (metal-ferroelectric-semiconductor) structures were studied and the estimated dielectric permittivity in the accumulation region of MFS structure nearly indicated the bulk value, suggesting a reasonably good Ba0.5Sr0.5TiO3/Si interface