Electrical properties of phase formation in LiNbO3 films grown by radio-frequency magnetron sputtering method

Thin polycrystalline films consisting of two phases: lithium niobate (LiNbO3) and lithium triniobates (LiNb3O8) were fabricated by the radio-frequency magnetron sputtering method. DC conductivity of as-grown films is affected by the hopping mechanism and influenced by the intergranular barrier 0.4 eV height associated with LiNb3O8 phase precipitated at the grain boundaries. Bulk grains (LiNbO3 phase) affect ac conductivity. Thermal annealing (TA) of the studied films leads to increase in the amount of LiNb3O8 phase due to diffusion of oxygen atoms towards the grain boundaries. As a result the bulk conduction component of the studied films after TA becomes a predominant factor.