Mode selection behavior of VHF thermal-piezoresistive self-sustained oscillators

The work demonstrates performance of thermal-piezoresistive self-sustained oscillators in both vacuum and ambient air conditions, up to 161MHz with AC peak-to-peak voltages of up to 44mV. The devices are of an I-shaped geometry fabricated from 1.6-1.9μm thick n-type silicon. While strong resonance is demonstrated in their intended in-plane longitudinal structural mode (g
_m
up to -238 μA/V), the device oscillation was verified by laser vibration sensing to occur in a different mode. Finite element simulation suggests that the longitudinally symmetric flexural mode is the mode of oscillation.