Growth of C-Axis Oriented LiNbO3 Film on Sapphire by Pulsed Laser Deposition for Surface Acoustic Wave Applications

Abstract

Highly c-axis oriented LiNbO3(006) thin films have been successfully grown on sapphire substrates by XeCl excimer pulsed laser deposition (PLD). The as-deposited films were characterized by X-ray diffraction, scanning electron microscope and atomic force microscopy to analyze their crystalline structure and surface morphology. The results show that highly c-axis oriented LiNbO3 thin films of 1 μm thickness were successfully grown on sapphire substrates by PLD. The full width at half maximum intensity of LiNbO3(006) peak of the sample fabricated under the optimum deposition parameters is only 0.15°. The center frequency of the LiNbO3/sapphire substrate with electrode width of 10 μm is 137 MHz, and phase velocities is 5480 m/s, which is much larger than that of the 36° Y-X LiNbO3 substrate (3632 m/s).