Deposition of c-axis oriented AIN films by rf magnetron sputtering for surface acoustic wave

C-axis oriented aluminum nitride (AlN) films were deposited on SiO2 coated Si substrates by reactive rf magnetron sputtering. Growth behaviors of the AlN films deposited at various deposition conditions such as rf power, sputtering pressure, nitrogen concentration and substrate temperature were investigated. Highly c-axis oriented AlN films were identified at substrate temperatures as low as 250 degrees Celsius. A densely pebble-like surface texture of c-axis oriented AlN films with an average grain size of about 100 nm was observed by scanning electron microscopy (SEM). The surface acoustic wave (SAW) characteristics with an interdigital transducer/AlN/SiO2/Si structure were studied. The phase velocity and the insertion loss measured by a network analyzer were 6080 m/sec and -24.8 dB, respectively.

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