Implementation of an accelerated electrical ageing protocol for Capacitive Micromachined Ultrasonic Transducers (CMUT)

In this paper, an accelerated electrical ageing protocol for CMUT devices is presented. The ageing protocol was applied on bare CMUT chip and then on fully packaged CMUT devices. The protocol is based on the use of a biasing voltage higher than the collapse voltage value, with an application time which varies up to a few thousand seconds. In parallel, the CMUT characteristics are monitored at regularly spaced times. Experimental characteristics are the capacitance-voltage cycle for the bare chip and sensitivity for the encapsulated device.