Longitudinal bulk a coustic mass sensor

Design, fabrication and characterization, in terms of mass sensitivity, is presented for a polycrystalline silicon longitudinal bulk acoustic cantilever. The device is operated in air at 51 MHz, resulting in a mass sensitivity of 100 HZ/fg (1 fg = 10
^-15
g). The initial characterization is conducted by depositing a minute mass by means of focused ion beam. The total noise in the currently applied measurement system allows for a mass resolution of 0.4 fg in air.