Electrical properties of ultrathin titanium dioxide films on silicon

Ultrathin (<50 nm) titanium dioxide (TiO2) films are being widely investigated as high-k dielectrics for future metal oxide semiconductor (MOS) technology. In this paper, ultrathin TiO2 films (similar to 20 nm) were deposited on silicon substrates by sputtering technique and subsequently annealed at 800 degrees C in oxygen environment for different durations (15-60 min). The annealed films were poly-crystalline in nature with rutile phase. The value of dielectric constant was found to be 32-60 at 1 kHz measurement frequency. Threshold voltages of the MOS structures were found to vary from -0.1 to -0.5V with the duration of annealing. Leakage current density (1 x 10(-2)-1 x 10(-8) A/cm(2) at 1V) and dielectric breakdown fields (8.15-9.8 MV/cm) were observed to improve with annealing time. (C) 2014 American Vacuum Society.