Dual-bottom-electrode CMUT based on standard CMOS process

A novel capacitive micromachined ultrasonic transducer (CMUT) with dual-bottom-electrode based on standard CMOS and post-CMOS processes is presented. Compared to the traditional CMUT with single-bottom-electrode, the presented one has larger equivalent gap in emission and smaller air gap in reception for the membrane is biased much closer to the bottom electrode. A structure model is proposed for the presented CMUT and finite element analysis (FEA) is carried out by commercial software ANSYS. Based on the simulation results, it is shown a 5.655dB improvement in maximum output pressure at 914 kHz without collapse, and a 9.3% improvement in maximum receive sensitivity for the presented CMUT compared with the traditional structure.