The role of Si3N4 layers in determining the texture of sputter deposited LiNbO3 thin films

Abstract

We report on the role of amorphous silicon nitride layers in determining the crystallographic orientation of lithium niobate sputter deposited on a layered substrate. In a structure consisting of LiNbO3/SiNx/SiO2/Si we show that details of the sputtering conditions of the SiNx, in particular, the nitrogen flow rate determine not only the deposition rate and index of refraction of the SiNx but also the orientation of the LiNbO3 subsequently deposited on it. Conditions that yield entirely c-axis LiNbO3 are reported and reasons for these observations are discussed.