Growth And Characterization Of Si-based LiNbO₃ Thin Film By PLD

The processes of depositing LiNbO₃ thin films by PLD are investigated in this paper. For Si-based optical waveguide and SAW applications, we deposited LiNbO₃ thin films on Si (111) substrates and Si(100) substrates with ZnO buffer layer, respectively, and systematically studied the growing parameters of LiNbO₃ films, such as substrate temperature, oxygen pressure, laser repetition, substrate-to-target distance and so on. Simultaneously, we also simply discuss the influence of post annealing on the crystalline quality of LiNbO₃ films. Additionally, we also simply investigate the deposition of LiNbO₃ films on other substrates, such as Si (100), glass and sapphire in the same optimized growing condition.The optimized conditions of growing LiNbO₃ films on silicon substrate including both Si (111) and ZnO/Si substrates by PLD are concluded: substrate temperature 600 °C, oxygen pressure 30Pa, laser repetition 3Hz and substrate-to-target distance 4cm. Additionally, we also investigate the influence of the thickness of ZnO buffer layer on the crystalline quality of LiNbO₃ thin films.The films are analyzed by several characterization equipments which show that the films deposited in the optimized condition are highly c-axis oriented columnar multi-crystal, have smooth surface and clear cross-sectional morphology. Their refractive index is very close to that of LiNbO₃ single crystal. We believe, due to their excellent crystalline quality, that the films would be very potential in the application of optical waveguide and SAW and useful for photo-acoustic-electric integration.