Properties of TiO2 Thin Films on GaAs Prepared by Metalorganic Chemical Vapor Deposition

Abstract

The deposition of polycrystalline TiO2 films on GaAs substrate is studied by metalorganic chemical vapor deposition (MOCVD) with Ti(i-OC3H7)4 and O2 as the precursors in a temperature range of 280–550°C. The structure, growth rate and grain size of TiO2 films depend on the deposition temperature. The film composition was measured by dispersive X-ray spectroscopy. From capacitance–voltage and current–voltage measurements of the Al/TiO2/GaAs/Au–Zn structure, the dielectric constant can reach 64 with the leakage current of 1×10-5 A/cm2 at 0.05 MV/cm at 350°C and the refractive index of TiO2 films can reach 2.2. At 300°C, the dielectric constant and leakage current density were 43 and 1×10-5 A/cm2 at 0.05 MV/cm and the refractive index of TiO2 films can reach 2.4.