Fabrication and electrical characterization of bottom-up silicon nanowire resonators

We present the fabrication and electrical characterization of nanomechanical resonators based on bottom-up grown silicon nanowires. The high piezoresistance coefficients of these nanowires provide an intrinsic transduction mechanism with good performance at high frequencies. We have characterized the frequency response of double clamped silicon nanowires with diameters of less than 100 nm. In particular, we have studied the first and second resonance modes, at frequencies higher than 190 MHz. We have observed the splitting of each resonance mode in two orthogonal vibration modes, which is attributed to the break-down of the axial symmetry of the nanowires. This effect can be used to improve the mass sensing performance of the devices.