Experimental Study on Resonant Response of Piezoresistive Double-clamped (111)-Si Nano-beam

In this work, the resonant response of piezoresistive double-clamped silicon nano-beam has been investigated. Conventional DRIE and KOH anisotropic etching were used to fabricate the 242 nm thick nano beam from doped (111) Si substrate. High energy argon ion bombardment was then applied on selected area of the top side of the nano beam to destroy the symmetry along thickness direction as atomic bonds were partly broken at top layer. The unbombarded layer underneath could maintain its piezoresistivity. The localized piezoresistor was used to study the resonant response of the double-clamped Si nanobeam in air and vacuum. The resonant frequency and Q-factor were obtained. Frequency shift to low end has been observed. The energy dissipation led by damaged atomic structure is discussed to explain the unexpected low Q factor.