Piezoelectric poling with temporary electrodes

A piezoelectric ultrasound sensor, comprising:

• a substrate layer;
• a plurality of permanent lower electrodes overlaying the substrate layer, wherein the plurality of permanent lower electrodes are electrically isolated from each other and are individually electrically connected to the substrate layer;
• a plurality of temporary electrodes at least partially overlaying the substrate layer, wherein each of the temporary electrodes is electrically connected to at least one of the permanent lower electrodes, and wherein each of the temporary electrodes is associated with at least one respective first removed region of temporary electrode material located between adjacent temporary electrodes;
• a piezoelectric layer overlaying the permanent lower electrodes and the temporary electrodes, wherein the piezoelectric layer includes a plurality of through holes, and wherein each of the through holes is associated with at least one of the removed regions;
• and
• an upper electrode overlaying the piezoelectric layer, wherein the upper electrode includes a plurality of second removed regions associated with the plurality of through holes;
• and
• processing circuitry electrically connected to the upper electrode and the plurality of temporary electrodes, wherein, to selectively activate ultrasonic transducers of the piezoelectric ultrasound sensor, processing circuitry is configured to apply a potential to the upper electrode and to selectively apply an activation signal to one or more of the permanent lower electrodes.

A system for poling a piezoelectric layer having a plurality of ultrasound transducers, comprising:

• a substrate layer comprising a first terminal;
• a plurality of permanent lower electrodes overlaying the substrate layer, wherein each permanent lower electrode of the plurality of permanent lower electrodes corresponds to a respective one of the plurality of ultrasonic transducers;
• a plurality of temporary electrodes overlaying the substrate layer, wherein the first terminal is electrically connected to the plurality of permanent lower electrodes by the plurality of temporary electrodes, wherein a first material of the plurality of temporary electrodes is a different material than a second material of the plurality of permanent lower electrodes, and wherein the first material is removable by a first etching process and the second material is not removable by the first etching process;
• a piezoelectric layer overlaying the plurality of permanent lower electrodes and the plurality of temporary electrodes;
• an upper electrode overlaying the piezoelectric layer;
• and
• a voltage source coupled to the first terminal and the upper electrode, wherein the voltage source is configured to apply a poling voltage between the first terminal and the upper electrode, and wherein the poling voltage comprises a voltage suitable to modify piezoelectric dipoles of the piezoelectric layer.