CMUT Chip with Integrated Temperature and Pressure Sensors

Abstract

Capacitive micromachined ultrasonic transducers (CMUTs) make extremely sensitive chemical sensors in air. In this work, we demonstrate a CMUT chemical sensor chip with integrated temperature and pressure sensors. These sensors allow the measurement of multiple environmental parameters using a single chip and allow the influence of temperature and pressure on the chemical sensors to be corrected for. Additionally, the CMUTs are designed to have low charging. We demonstrate the use the temperature sensor to correct for resonance frequency variations due to temperature. With temperature correction, we measure the drift of two chemical sensors to be 19 parts per million and 59 parts per million over 12 hours. This is progress towards being able to make continuous measurements with the chemical sensor without comparing to a reference gas.