Growth of c-Axis-Oriented LiNbO3 Films on ZnO/SiO2/Si Substrate by Pulsed Laser Deposition for Surface Acoustic Wave Applications

Highly c-axis-oriented LiNbO3(006) thin films were successfully grown on SiO2/Si substrates with a ZnO buffer layer by XeCl excimer pulsed laser deposition (PLD). The as-deposited films were characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy to analyze their crystalline structure and surface morphology. The results show that the highly c-axis-oriented LiNbO3 thin films of 2.5 mu m thickness were successfully grown on SiO2/Si substrates with a ZnO buffer layer by PLD. The full width at half maximum intensity of the LiNbO3(006) peak of the sample fabricated under the optimum deposition conditions is only 0.18 degrees. The center frequency of the LiNbO3/ZnO/SiO2/Si substrate with line width of 4 mu m is 188 MHz, and the phase velocity is 3010 m/s, which is slightly lower than that of the 36 degrees Y-X LiNbO3 substrate. [DOI: 10.1143/JJAP.47.4056]