Total-Ionizing-Dose Effects on Piezoelectric Micromachined Ultrasonic Transducers.

Total-ionizing-dose (TID) effects on piezoelectric micromachined ultrasonic transducers (pMUTs) are investigated using 10-keV X-rays under different bias conditions. The corresponding changes in resonant frequency and quality factor are evaluated using impedance analysis methods. Radiation-generated electrons or holes are trapped in the pre-existing defects of piezoelectric materials. Therefore, the sensitivity of pMUTs to X-ray irradiation depends strongly on the device bias during irradiation. The trapped charges change stress and strain in the materials due to the inverse piezoelectric effect, resulting in resonant frequency shifts and quality factor variation. [ABSTRACT FROM PUBLISHER]