Title :
Diaphragm stress control for sensitivity improvement of piezoelectric ultrasonic microsensors on silicon dioxide diaphragms
Author :
Yamashita, K. ; Watanabe, T. ; Yoshizaki, T. ; Noda, M. ; Okuyama, M.
Author_Institution :
Kyoto Inst. of Technol., Kyoto, Japan
Abstract :
Piezoelectric ultrasonic microsensors have been fabricated using sol-gel derived PZT (Pb(Zr,Ti)O3) thin films on micromachined silicon dioxide diaphragms made from a normal silicon wafer instead of the conventional SOI (silicon on insulator) wafer process. The layered structure of the PZT capacitor part on the diaphragm has been modified in order to control the total lateral stress in the diaphragm for sensitivity enhancement. The sensors having an island-like structure in the PZT layer have shown over 2 times higher sensitivity than conventional sensors.
Keywords :
diaphragms; microsensors; piezoelectric transducers; silicon compounds; stress control; ultrasonic transducers; PZT; PZT capacitor; PZT thin films; diaphragm stress control; piezoelectric ultrasonic microsensors; silicon dioxide diaphragms; Electrodes; Fabrication; Microsensors; Piezoelectric films; Semiconductor thin films; Sensor phenomena and characterization; Silicon compounds; Silicon on insulator technology; Sputtering; Stress control; PZT; Ultrasonic sensor; diaphragm; lateral stress; sensitivity;
Conference_Titel :
Solid-State Sensors, Actuators and Microsystems Conference, 2009. TRANSDUCERS 2009. International
Conference_Location :
Denver, CO
Print_ISBN :
978-1-4244-4190-7
Electronic_ISBN :
978-1-4244-4193-8
DOI :
10.1109/SENSOR.2009.5285498
