Deposition and structural properties of piezoelectric ZnO epitaxial film on p-InP (1Â 0Â 0) substrate for FBAR

R.F. magnetron sputtering grown ZnO films on p-InP (1 0 0) substrates without any metallic bottom electrode were studied to investigate a possibility of this structure for FBAR application, although the substrate has a relatively high resistance. AFM images showed that the root mean square of the average surface roughness of the ZnO film was 5.88 Å, and X-ray diffraction and transmission electron microscopy (TEM) measurements showed that the ZnO film grown on the InP were textured (or epitaxy) films with strong (0 0 0 1) preferential orientation. Auger electron spectroscopy and bright-field TEM measurements showed that the ZnO epitaxial films grown on InP at 200 °C had no any significant interdiffusion problems. These results indicate that the ZnO epitaxial films grown on p-InP (1 0 0) at low temperature hold promise for FBAR devices based on compound semiconductors substrates, such as InP and InSb, without metallic bottom electrode.