Structural and electrical properties of BaTiO₃ thin films grown on p-InSb substrate by metalorganic chemical vapor deposition at low temperature

Metalorganic chemical vapor deposition of BaTiO₃ on p-InSb (111) using Ba(tmhd)₂, Ti(OC₃H₇)₄, and N₂O via pyrolysis at low (∼300°C) temperature was performed to produce high-quality BaTiO₃/p-InSb (111) interfaces and BaTiO ₃ insulator gates with dielectric constants of high magnitude. Raman spectroscopy showed the optical phonon modes of a BaTiO₃ thin film. The stoichiometry of the BaTiO₃ film was investigated by Auger electron spectroscopy. Transmission electron microscopy showed that the BaTiO₃ films had local epitaxial formations. Room-temperature capacitance-voltage measurements clearly revealed metal-insulator-semiconductor behavior for the samples with the BaTiO₃ insulator gates, and the interface state densities at the BaTiO₃/p-InSb interfaces were approximately high 10¹¹ eV^-1 cm^-2 at the middle of the InSb energy gap. The dielectric constant determined from the capacitance-voltage measurements was as large as 743. These results indicate that the BaTiO₃ layers grown at low temperature can be used for both high-density dynamic-memory and high-speed applications.