Development of Micro Array Sensor for Aerial Ultrasonic of 1 MHz

Abstract

We developed a MEMS ultrasonic array sensor that is capable of detecting 1 MHz airborne ultrasonic waves for use in devices for inspecting the interior of objects. The sensor is an array of vibrating membranes, each consisting of a metal lower electrode, a platinum upper electrode, and a polymer ferroelectric layer between them. In this study, two kinds of electrode materials, aluminum or gold, were used for the lower electrode to investigate how they affect the characteristics of such high resonant-frequency sensors. The sensor using aluminum showed about four times better sensitivity than that using gold.