An exemplary surface acoustic wave device includes a DLC film, a zinc
oxide film formed on the DLC film, and at least one interdigital
transducer formed on the zinc oxide film. The DLC film has a nano-sized
thickness Z(f), corresponding to the surface acoustic wave device having
an operational frequency f ranging from 20 to 1,000 GHz, satisfying the
condition (1): Z(f)=M.times.Z.sub.0/(f/f.sub.0), and Z(f).gtoreq.1
nanometer. The zinc oxide film has a nano-sized thickness Y(f),
corresponding to the surface acoustic wave device having the operational
frequency f, satisfying the condition (2):
Y(f)=N.times.Y.sub.0/(f/f.sub.0). The Z.sub.0 and Y.sub.0 respectively
are the thicknesses of the DLC film and the zinc oxide film corresponding
to an operational frequency f.sub.0 of the surface acoustic wave device.