Characterization of thin ZrO2 films deposited using Zr(O '-Pr)(2)(thd)(2) and O-2 on Si(100)

Abstract

The properties of ZrO2 films deposited using molecular oxygen and a recently developed precursor, zirconium Zr(O-i-Pr)(2)(thd)(2) have been investigated. The organometallic was dissolved as a 0.15 molar solution in octane and introduced into the deposition chamber using a liquid injection system. The deposition rate was insensitive to molecular oxygen flow but changed with liquid injection rate and was thermally activated in the range 390 degreesC-550 degreesC. Carbon concentrations, <0.1 at.%, the detection limit of the x-ray photoelectron spectroscopy depth profiling measurements, were obtained at the lowest deposition temperatures and deposition rates. High-resolution transmission electron microscopy showed the films to be polycrystalline as deposited, with a zirconium silicate interfacial layer. After proper annealing treatments, an equivalent oxide thickness (EOT) of around 2.3 urn has been achieved for a 5.2 nm thick film, with a leakage current two orders of magnitude lower than that Of SiO2 with the same EOT. Promising capacitance-voltage characteristics were also achieved, but some improvements are required if these films are to be used as a gate insulator. (C) 2002 American Vacuum Society.