Electrical and structural characteristics of PbTiO3 thin films with ultra-thin Al2O3 buffer layers

Polycrystalline PbTiO3 thin films have been prepared on Si substrates with ultra-thin SiO2 and Al2O3 buffer layers by chemical solution deposition, respectively. Although capacitance–voltage characteristics show hysteresis loops in both cases, the memory window of PbTiO3/Al2O3 stacked dielectric is 3.3 V larger than that on SiO2. In addition, well-behaved capacitance–voltage characteristics are only obtained in PbTiO3/Al2O3 and the PbTiO3 films on Al2O3 have the dielectric constant of 116 larger than 42 of PbTiO3 films on SiO2. The leakage current density of PbTiO3/Al2O3 dielectric is 1.3×10−7 A cm−2 at −2.5 V, which is low enough for deep sub-μm application.