A Row-Column (RC) Addressed 2D Capacitive Micromachined Ultrasonic Transducer (CMUT) Array on a Glass Substrate: Preliminary Results.

In this work, we present preliminary characterization results from a 32 x 32 row-column (RC) addressed 2D capacitive micromachined ultrasonic transducer (CMUT) array. The device was fabricated using anodic bonding on a borosilicate glass substrate, which eliminates the substrate - bottom electrode coupling previously observed in traditional CMUT RC arrays fabricated on silicon substrates. The characterization results were compared for the top and bottom electrodes and include impedance measurements, pulseecho impulse responses, and 2D scans of the pressure field using a calibrated hydrophone. The results showed that the array elements behave similarly when ground and hot electrodes were switched between the top and bottom electrodes for all of the measured parameters including device capacitance, center frequency, and pulse-echo response amplitude. The pressure scans verified the highly customizable nature of RC arrays by showing multiple active element configurations. A sample cross-sectional image of a metal target was also demonstrated.