抄録
Piezoelectric ultrasonic microsensors have been fabricated on buckling-controlled silicon dioxide diaphragms for sensitivity enhancement. A precise stress control process has been developed for fragile SiO2 diaphragms, which are derived from a surface oxidized normal silicon wafer, to allow spontaneous buckling and to make re-buckle upward. The fabricated sensors on upward- and downward-buckled SiO2 diaphragms have been evaluated in terms of static deflection and sensitivity. The upward-buckled diaphragms show the deflection around +4.8μm while the downward ones show that around -3.5μm. Totally a four times higher sensitivity is obtained on average of forty sensors in the comparison of the upward diaphragm sensors to the downward ones.
