Electrical properties of amorphous films and crystallization of Li–Nb–O system on silicon

Abstract

Li–Nb–O amorphous films were deposited onto Si substrates by the radio-frequency magnetron sputtering method in an Ar environment. As-grown films are crystallized under thermal annealing (TA) at the temperature of up to 600 °C with a formation of LiNbO3. Capacitance–voltage and current–voltage analysis revealed a positive fixed oxide charge existed in the films. TA influences the structure and electrical properties of as-grown films. The fraction of a crystalline phase in the film increases from 45 to 100% when raising the annealing temperature from 450 to 475 °C. The effective positive charge in the amorphous films changes non-monotonically with TA reaching a minimum value at the temperature of 450 °C when the effective dielectric constant has a maximum value. The concentration of traps in the films depends on the annealing temperature and reaches a minimum value at T = 600 °C which is caused by the formation of the large-block crystalline structure. Charge transport mechanisms are also discussed.