Ultrasonic transducers in complementary metal oxide semiconductor (CMOS) wafers and related apparatus and methods

摘要

Micromachined ultrasonic transducers formed in complementary metal oxide semiconductor (CMOS) wafers are described, as are methods of fabricating such devices. A metallization layer of a CMOS wafer may be removed by sacrificial release to create a cavity of an ultrasonic transducer. Remaining layers may form a membrane of the ultrasonic transducer.

主权项

1. A complementary metal oxide semiconductor (CMOS) wafer, comprising:
a semiconductor substrate; an ultrasonic transducer comprising: a cavity created by a partial removal of a first metallization layer of the CMOS wafer; an electrode disposed between the cavity and the semiconductor substrate; and an acoustic membrane comprising a dielectric layer and a second metallization layer of the CMOS wafer, the cavity being disposed between the semiconductor substrate and the acoustic membrane; and an integrated circuitry in the semiconductor substrate, coupled to the ultrasonic transducer and configured to control operation of the ultrasonic transducer; wherein the electrode disposed between the cavity and the semiconductor substrate is a first electrode of the ultrasonic transducer, and wherein the ultrasonic transducer further comprises a second electrode disposed opposite the first electrode, the second electrode disposed in the acoustic membrane between the cavity and the second metallization layer.