US Patent 7888709 Capacitive micromachined ultrasonic transducer and manufacturing method

The integrated circuit/transducer device of the preferred embodiment includes a substrate, a complementary-metal-oxide-semiconductor (CMOS) circuit that is fabricated on the substrate, and a capacitive micromachined ultrasonic transducer (cMUT) element that is also fabricated on the substrate. The CMOS circuit and cMUT element are fabricated during the same foundry process and are connected. The cMUT includes a lower electrode, an upper electrode, a membrane structure that support the upper electrode, and a cavity between the upper electrode and lower electrode.