Pre-snapback mode operation of CMUT for enhanced acoustic performance.

Capacitive micromachined ultrasonic transducers (CMUTs) offer advantages over traditional piezoelectric devices for ultrasound applications, including broader bandwidth, miniaturization, and electronics integration, but are limited by low acoustic pressure in conventional operation. Here, we introduce a pre-snapback mode of CMUT operation that enhances acoustic output while maintaining device stability. Using a new analytical donut-plate model, we optimize CMUT cell design to expand the pre-snapback region and maximize electromechanical coupling. We demonstrate a stable pre-snapback regime with transmission and reception sensitivities surpassing those of conventional CMUTs and commercial piezoelectric devices. B-mode imaging using the CMUT array confirms improved image contrast and penetration under identical bias conditions. Furthermore, the pre-snapback mode shows stable long-term operation with reduced dielectric and mechanical stress. This work establishes pre-snapback CMUT operation as a high-performance, reliable regime, unlocking new possibilities for fully integrated ultrasound systems in clinical and therapeutic applications.