Fabrication of AlN Films by RF Magnetron Sputtering for Surface Acoustic Wave Applications

Highly c-axis oriented AlN films were successfully deposited on SiO2/Si and sapphire substrates by RF magnetron sputtering. The optimum deposition conditions are nitrogen gas ratio (N-2/Ar + N-2) of 40%, RF power of 400W, deposition pressure of 4 mTorr, and substrate temperature of 200 degrees C. The full width at half maximum intensity of AlN(002) peak of AlN films on SiO2/Si and sapphire substrates sputtered at the optimum deposition conditions were about 0.26 degrees and 0.2 degrees, respectively. The phase velocity of the fabricated SAW device with AlN/SiO2/Si and AlN/sapphire layered structure was estimated to be about 4996 and 5589m/s, respectively.