PIEZOELECTRICALLY DRIVEN SILICON BEAM FORCE SENSOR

A resonant silicon beam force sensor with piezoelectric excitation and detection is being developed. The realization is based on IC and thin-film technology with ZnO as the piezoelectrical layer. The theory, realization and measurements of a bent-frame sensors are described. A frequency shift of about 3.3 times the unloaded resonance frequency f0 (f0 congruent-to 6 kHz) is measured with an external load force up to 0.4 N. The absolute sensitivity of the force sensor is 64 kHz/N and the full-scale sensitivity is 29 kHz/N. Using a simple model for the load-force transduction from external to sensor force, the measurements are in good agreement with the theory.