Ferroelectric BaTiO 3 films with a high-magnitude dielectric constant grown on p-Si by low-pressure metalorganic chemical vapor deposition

Abstract

Metalorganic chemical vapor deposition of BaTiO 3 using Ba(tmhd) 2, Ti(OC 3H 7) 4, and N 2O via pyrolysis at relatively low temperature (∼ 600°C) was performed in order to produce a BaTiO 3 insulator gate with a high-quality BaTiO 3 p-Si interface and with a dielectric constant of high magnitude. X-ray diffraction and transmission electron microscopy results showed that the as-grown BaTiO 3 films on p-Si substrates were polycrystalline. The stoichiometry of the BaTiO 3 films was observed by Auger electron spectroscopy. Room-temperature current-voltage and capacitance-voltage measurements clearly revealed a metal-insulator-semiconductor behavior for the samples with a BaTiO 3 insulator gate, the interface state densities at the BaTiO 3 p-Si were approximately in the low 10 11 eV −1 cm −2 at the middle of the Si energy gap, and the dielectric constant determined from the 1 MHz C- V profile was as large as 200. These results indicate that the BaTiO 3 layers grown by MOCVD can be used for high-density memories.