Attenuation of surface acoustic waves propagating on a metallized ST-cut quartz

Measurements of attenuation and velocity change of surface acoustic waves (SAW) in ST-cut quartz were carried out at various frequencies, during a vapor deposition of indium and silver. The measurements were performed with the substrate held at room temperature and at liquid nitrogen temperature. We observed that the attenuation, within the experimental error, is linearly proportional to the SAW frequency. It was also found that the coarser the structure of the semicontinuous film, the lower the attenuation. The existing theories are critically discussed and an alternative explanation is suggested.