Membrane Supported AlN FBAR Structures Obtained by Micromachining of High Resistivity Silicon

This paper presents the manufacturing and the characterization of AIN membrane supported F-BAR structures. The 2 μm thin AIN layer was grown using sputtering techniques, on a high resistivity (111) oriented silicon substrate. Conventional contact lithography, e-gun Ti/Au evaporation and lift-off techniques were used to define top-side metallization of the the FBAR structures. Bulk micromachinig techniques were used for the release of the AIN membrane. The bottom side metallization of the micromachined structure was obtained by means of sputtered gold. S-parameter measurements have shown a resonance around 1.6 GHz. The extracted value of acoustic velocity is in good agreement with that reported by other authors on materials fabricated by other methods.