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Polycrystalline PbTiO 3 thin films have been prepared on Si substrates with ultra-thin SiO 2 and Al 2 O 3 buffer layers by chemical solution deposition, respectively. Although capacitance–voltage characteristics show hysteresis loops in both cases, the memory window of PbTiO 3 /Al 2 O 3 stacked dielectric is 3.3 V larger than that on SiO 2 . In addition, well-behaved capacitance–voltage characteristics are only obtained in PbTiO 3 /Al 2 O 3 and the PbTiO 3 films on Al 2 O 3 have the dielectric constant of 116 larger than 42 of PbTiO 3 films on SiO 2 . The leakage current density of PbTiO 3 /Al 2 O 3 dielectric is 1.3×10 −7 A cm −2 at −2.5 V, which is low enough for deep sub-μm application.