Gigabit-scale DRAM capacitor technology with high dielectric constant thin films by a novel conformal deposition technique

High dielectric constant Ba/sub 0.7/Sr/sub 0.3/TiO/sub 3/ (BST) thin films with excellent thickness uniformity, within 5%, and adequate structural properties across an 8 inch wafer, are prepared by a novel aerosol-driven and photo-enhanced conformal deposition technique. Storage capacitors fabricated with an ultrathin BST film which has the lowest equivalent SiO/sub 2/ thickness of 0.37 nm reported thus far, show that leakage current density is 2/spl times/10/sup -8/ A/cm/sup 2/ under an applied voltage of 2 V and unit capacitance is 95 fFspl mu/m/sup 2/. Combining these material properties with the proposed conformal deposition technique which is applicable for stacked cell structures, is very promising as key technologies for the future gigabit-scale DRAMs.<
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