A frequency selective device utilizing the mechanical resonance of a silicon substrate

This communication describes an approach to tuned monolithic circuitry which utilizes the mechanical resonance of a silicon substrate. The proposed device is compatible with monolithic technology and will operate from a few hundred cycles to hundreds of kilocycles. The basic device consists of a silicon cantilever mechanically deflected by electrically induced thermal expansion. Diffused silicon piezo-resistive elements are used to detect stress in the cantilever and provide an electrical output. Maximum stress and electrical output occur when the cantilever is driven at its mechanical resonant frequency.