Optical and electrical properties of titanium dioxide films with a high magnitude dielectric constant grown on p-Si by metalorganic chemical vapor deposition at low temperature

Abstract

Metalorganic chemical vapor deposition of titanium dioxide (TiO₂) on p‐Si(100) using titanium isopropoxide and nitrous oxide via pyrolysis at relatively low (∼500 °C) temperature was performed to produce high quality TiO₂/p‐Si interfaces and to fabricate TiO₂ insulator gates with a dielectric constant of high magnitude. Scanning electron microscopy shows that the surfaces of the TiO₂ films have very smooth morphologies. From the x‐ray diffraction analysis, the grown layer was found to be a polycrystalline film. Raman spectroscopy showed the optical phonon modes of a TiO₂ thin film. The stoichiometry of the TiO₂ film was investigated by Auger electron spectroscopy. Room‐temperature current‐voltage and capacitance‐voltage measurements clearly revealed metal‐insulator‐semiconductor behavior for the samples of the Ag/TiO₂/p‐Si. The interface state density at the TiO₂/p‐Si interface was approximately high 10¹¹ eV⁻¹ cm⁻² at the middle of the Si energy gap, and the dielectric constant determined from the capacitance‐voltage measurements was as large as 73. These results indicate the TiO₂ layers grown at relatively low temperature can be used for high density dynamic memory.