A silicon electrostatic ultrasonic transducer

TLDR

A silicon IC process is used to fabricate an electric ultrasonic transducer, with design choices aimed at achieving high sensitivity and targeted frequency responses in air. The device achieves a transmitter sensitivity of 19.1 dB at 150 kHz and a receiver sensitivity of 0.47 mV/Pa across 10–130 kHz, supports electronic sector scanning with a seven‑element linear array, and offers design guidance for phased‑array transducers with integrated scanning.

Abstract

An electric ultrasonic transducer is developed by using a silicon IC process. Design considerations are first presented to obtain high sensitivity and the desired frequency responses in air. The measured transmitter sensitivity is 19.1 dB (0 dB=1 mubar/V) at a point 50 cm away from the devices, when the devices are operated at 150 kHz. The receiving sensitivity is 0.47 mV/Pa in the 10-130-kHz range, with bias voltages as low as 30 V. An electronic sector scanning operation is also achieved by time-sequentially driving seven elements arranged in a linear array on the same chip. The results should be helpful in the design of phased-array transducers integrated with electronic scanning circuits.