Abstract: An ultrasonic transducer device includes a first electrode, an insulating layer, an oscillating membrane, a second electrode, and a third electrode. The insulating layer is disposed on the first electrode. The oscillating membrane is disposed over the insulating layer. A cavity is between the oscillating membrane and the insulating layer. The second electrode is disposed on the oscillating membrane. The third electrode is disposed in the cavity and has a plurality of first electrode openings overlapping the second electrode. The second electrode and the third electrode are each located at different sides of the oscillating membrane.