Title :
A low voltage CMOS-based capacitive micromachined ultrasonic sensors development
Author :
Tien, Y. ; Ku, P. ; Lin, Fujian ; Li, Peng ; Lu, Li ; Kuo, Ping-Huan ; Tian, Wei
Author_Institution :
Grad. Inst. of Electron. Eng., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
This paper presents a high performance capacitive micromachined ultrasound sensor (CMUS) with a large fractional bandwidth (FB) ~113 % and a low bias voltage of 5 V in an immersion testing of an ultrasonic sensor. The thin polysilicon for the CMOS gate was utilized as a sacrificial layer and the multiple layers of metal and dielectric for the CMOS electric interconnects were used as the structural layer to decrease the effective gap, which resulted in a lower bias voltage, between two electrodes. An etching ditch design to release the CMUS membrane was demonstrated successfully to increase the sensor yield in the post CMOS MEMS processing. To further improve the sensitivity of the CMUS, our ASIC was integrated with the CMUS and a great sensitivity of 45dB was obtained.
Keywords :
CMOS integrated circuits; application specific integrated circuits; capacitive sensors; electrochemical electrodes; elemental semiconductors; integrated circuit interconnections; integrated circuit testing; low-power electronics; membranes; micromachining; microsensors; silicon; ultrasonic transducers; ASIC; CMOS electric interconnection; CMUS membrane; FB; Si; electrode; etching ditch design; fractional bandwidth; gain 45 dB; immersion testing; low voltage CMOS-based capacitive micromachined ultrasonic sensor development; multiple dielectric layer; multiple metal layer; post CMOS MEMS processing; sacrificial layer; voltage 5 V; Application specific integrated circuits; CMOS integrated circuits; Electrodes; Etching; Metals; Sensitivity; Sensors;
Conference_Titel :
Sensors, 2012 IEEE
Conference_Location :
Taipei
Print_ISBN :
978-1-4577-1766-6
Electronic_ISBN :
1930-0395
DOI :
10.1109/ICSENS.2012.6411141
