Static deflection control for sensitivity enhancement of piezoelectric ultrasonic microsensors on silicon dioxide diaphragms

Sensitivity of piezoelectric ultrasonic microsensors has been enhanced through static deflection control on silicon dioxide diaphragm structures. A precise deflection control process has been developed for fragile SiO
₂
diaphragms derived from a both-side oxidized normal silicon wafer. The diaphragms have been re-buckled upward without breaking and the sensitivity has been improved by four times on average on the deflection-controlled SiO
₂
diaphragm sensors.