AlN films were grown on silicon substrates by RF reactive magnetron sputtering. At high sputtering powers, (002) preferred orientation as well as Al-N absorption band becomes prominent. The surface roughness and grain size of sputtered films were found to increase with RF power. Surface acoustic wave (SAW) device has been made on the grown (002) oriented piezoelectric AlN film with interdigital transducer (IDT) electrodes spacing corresponding to a wavelength of 60 μm. The centre frequency of the SAW filter was found to be 84.304 MHz, which gives a phase velocity of 5058 m/s with an electromechanical coupling coefficient (K 2) of 0.34%. Low etch rate of AlN films were observed in doped TMAH solution. Threedimensional suspended Cr/AlN/Cr/SiO 2 microstructures were also fabricated by wet chemical etching. © ASM International.