New perovskite nanomaterials and their integrations into high-k dielectrics

We report on a bottom-up manufacturing for high-k dielectric films using a novel nanomaterial, namely, a perovskite nanosheet (LaNb₂O ₇) derived from a layered perovskite by exfoliation. Solution-based layer-by-laver assembly of perovskite nanosheets is effective for room-temperature fabrication of high-k nanocapacitors, which are directly assembled on a SrRuO₃ bottom electrode with an atomically sharp interface. These nanocapacitors exhibit high dielectric constants (k > 50) for thichiess down to 5 nm while eliminating problems resulting from the size effect. We also investigate dielectric properties of perovskite nanosheets with different compositions (LaNb₂O₇, La_0.95Eu _0.05Nb₂O₇ and Eu_0.56Ta ₂O₇) in order to study the influence of A- and B-site modifications on dielectric properties.