Microfabricated ultrasonic transducer having individual cells with electrically isolated electrode sections
An ultrasonic transducer includes a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell. Portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another. Each portion of the bottom electrode corresponds to each individual transducer that cell further includes a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another.
1. An apparatus, comprising:
an ultrasonic transducer substrate having a membrane, a bottom electrode, and a plurality of cavities disposed between the membrane and the bottom electrode, each of the plurality of cavities corresponding to an individual transducer cell;
wherein portions of the bottom electrode corresponding to each individual transducer cell are electrically isolated from one another; and
each portion of the bottom electrode corresponding to each individual transducer cell further comprising a first bottom electrode portion and a second bottom electrode portion, the first and second bottom electrode portions electrically isolated from one another;
first trench isolation regions disposed within the bottom electrode and configured to electrically isolate each individual transducer cell from one another; and
second trench isolation regions disposed within the bottom electrode and configured to electrically isolate the first and second bottom electrode portions of an individual transducer cell from one another;
the apparatus further comprising an electrical substrate bonded to the ultrasonic transducer substrate.
2. The apparatus of claim 1 , wherein the membrane serves as a top electrode for each of the individual transducer cells.
3. The apparatus of claim 1 , wherein the first and second bottom electrode portions of an individual transducer cell are separately electrically addressable from one another.
4. The apparatus of claim 1 , wherein the first bottom electrode portion comprises an inner bottom electrode with respect to a diameter of the transducer cell, and the second bottom electrode portion comprises an outer bottom electrode with respect to the diameter of the transducer cell.
5. The apparatus of claim 1 , wherein the electrical substrate comprises one of: a CMOS substrate, an analog circuit substrate, an interposer substrate, a printed circuit board (PCB) substrate, and a flexible substrate.
6. The apparatus of claim 5 , wherein:
the electrical substrate comprises a CMOS substrate;
one of the first bottom electrode portion and the second bottom electrode portion is configured to perform a transmit function of the apparatus; and
the other of the first bottom electrode portion and the second bottom electrode portion is configured to perform a receive function of the apparatus.