Design and development of capacitive ultrasonic transducer using silicon micromachining techniques

Abstract

Ultrasound has many applications such as ranging, nondestructive evaluation, gas flow measurement, and acoustic microscopy. Conventional piezoelectric transducers perform poorly for these applications due to the lack of proper matching layer materials between the transducer and air. Capacitive ultrasonic transducers promise higher efficiency and broader bandwidth performance for these applications. The capacitive ultrasonic transducer developed in this project is based on standard silicon micromachining technology. It consists of a metalized membrane (top electrode) suspended above a heavily doped silicon backplate (bottom electrode).