Selection of post-growth treatment parameters for atomic layer deposition of structurally disordered TiO2 thin films

Routes to atomic layer-deposited TiO2 films with decreased leakage have been studied by using electrical characterization techniques. The combination of post-deposition annealing parameters, time and temperature, which provides measurable aluminum-titanium oxide-silicon structures - i.e., having capacitance-voltage curves which show accumulation behavior - are 625 °C, 10 min for p-type substrates, and 550 °C, 10 min for n-type substrates. The best annealing conditions for p-type substrates are 625 °C with the length extended to 30 min, which produces an interfacial state density of about 5-6 × 1011 cm−2 eV−1, and disordered-induced gap state density below our experimental limits. We have also proved that a post-deposition annealing must be applied to TiO2/HfO2 and HfO2/TiO2/HfO2 stacked structures to obtain adequate measurability conditions.