Deposition of stress free c-axis oriented LiNbO3 thin film grown on (002) ZnO coated Si substrate

C-axis oriented lithium niobate thin films have been deposited on Si substrate using RF sputtering technique. A thin buffer layer of c-axis (002) oriented ZnO on Si substrate has been used as a nucleating layer to promote the growth of (006) oriented LiNbO3 film. The processing gas composition and pressure are found to be very critical in obtaining stress free LiNbO3 film having desired (006) orientation. The LiNbO3 films deposited under unique combination of sputtering pressure (10 mTorr) and argon percentage (80%) in reactive gas (Ar + O2) composition become almost stress free having lattice parameter (1.3867 A) close to the bulk value. The observed variation in the structural properties and optical phonon modes observed by Raman spectroscopic studies of the oriented LiNbO3 thin film with stress has been correlated with growth kinetics.