Differential π-shaped CMUTs with improved linearity and sensitivity

Abstract

High performance π-shaped capacitive micro-machined ultrasonic transducers (CMUTs) are presented with improved linearity and sensitivity. The π-shaped CMUT is composed of an anchor membrane, a circular piston electrode plate, and a bridging layer. The proposed differential π-shaped CMUT can provide differential output signals and further increase the sensitivity by about 6 dB. Both π-shaped CMUTs were designed and verified in a TSMC 1P6M 180nm CMOS MEMS technology. Experimental results show that the differential π-shaped CMUT not only provides superior linearity under 0-0.6 MPa pressure, but also exhibits 1.6 and 2.46 times in sensitivity compared to the conventional CMUT architecture.