Research in LPE of Doped LiNbO3 and LiTaO3 Thin Films

摘要

The crystal chemical approach has been shown to be successful in improving the temperature stability of ferroelectric LiNbO3 phase. LiNbO3 films doped with cations that are larger than Li+ and Nb5+, e.g., Na+, Na+ + Ta5+, Ag+, Co2+ + Zr4+, etc., have successfully been grown by the liquid phase epitaxial (LPE) technique using the vanadium containing flux systems. X-ray diffraction studies indicate that the films grown from the vanadium containing fluxes have a high single crystallinity with good epitaxy. To date, the temperature coefficient of SAW velocity was reduced by 40%; this translates into 40% improvement in the temperature stability of LiNbO3 SAW devices. This is a significant result in the present work and opens a new interest in the LiNbO3 family for SAW application. By using such a novel approach, it should be possible to improve the temperature stability of other important structural families such as quartz or tungsten bronze structural family compositions.