Empirical model for dielectric charging in double-SOI-wafer-bonded CMUTs: Theory and experiment

We performed charging experiments with double SOI wafer bonded CMUTs by capacitance measurement methods over short term and long term charging periods. An empirical model has been built, which quantitatively characterizes the surface and volume charging effects by using different charging time constants and distribution factors. This model agrees well with the experiment data and has better accuracy compared to other models. Discharge events have been observed, which alter the charging rate.