Comparative study on electrical properties of atomic layer deposited high-permittivity materials on silicon substrates

Deep level transient spectroscopy, capacitance-voltage and conductance transient measurement techniques have been applied in order to evaluate the electrical quality of thin high-permittivity oxide layers on silicon. The oxides studied included HfO2 film grown from two different oxygen-free metal precursors and Ta2O5 and Nb2O5 nanolaminates. The interface trap densities correlated to the oxide growth chemistry and semiconductor substrate treatment. No gap state densities induced by structural disorder were measured in the films grown on chemical SiO2. Trap densities were also clearly lower in HfO2 films compared to Ta2O5-Nb2O5.