A self-calibrating barrier-detector microsystem in standard silicon circuit technology

The realization of an ultrasound barrier system using micromachined silicon membranes is discussed. The transducer membranes are fabricated using a standard bipolar/CMOS process plus one additional etching step which facilitates the co-integration of sensor and read-out electronics. A transmitter and receiver incorporating a self calibrating scheme to overcome matching problems between transmitter and receiver resonance frequencies are described.