Capacitive micromachined ultrasonic transducer (CMUT) device with through-substrate via (TSV)

A Capacitive Micromachined Ultrasonic Transducer (CMUT) device, comprising:

• a CMUT cell including:
• a substrate including a top side and a bottom side;
• a dielectric layer over the top side of the substrate, the dielectric layer having a first region and a second region laterally surrounded by the first region and thinner than the first region, the first and second regions defining a cavity;
• a membrane layer bonded directly on the first region of the dielectric layer and enclosing the cavity over the second region of the dielectric layer, the membrane layer including a movable membrane movable within the cavity;
• a through-substrate via (TSV) penetrating the substrate, the dielectric layer, and the membrane layer, and the TSV positioned laterally away from the movable membrane, the TSV including a conductive filler extending from the bottom side of the substrate to be coplanar with the membrane layer;
• and
• a metal layer contacting the conductive filler above the top side of the substrate, the metal layer extending laterally along the membrane layer and contacting the movable membrane.