THIN FILM ULTRASOUND TRANSDUCER

摘要

The present invention relates to a transducer (11) comprising
a membrane (31) configured to change shape in response to a force, the membrane (31) having a first major surface (16) and a second major surface (17),a piezoelectric layer (18) formed over the first major surface (16) of the membrane (31), the piezoelectric layer (18) having an active portion,first and second electrodes (19) in contact with the piezoelectric layer (18), wherein an electric field between the first and second electrodes (19) determines the mechanical movement of the piezoelectric layer (18),support structures (40) at the second major surface (17) of the membrane (15) on adjacent sides of the active portion of the piezoelectric layer (18), at least part of the support structures (40) forming walls perpendicular, or at least not parallel, to the second major surface (17) of the membrane (31), so as to form a trench (41) of any shape underlying the active portion, so that an ultrasound transducer is obtained with a high output pressure at the support side than at the opposite side.

The invention also relates to a method of forming such a transducer, and an array comprising at least one transducer of the like.

主权项

1. A method of forming a transducer (11), the method comprising:
obtaining a substrate (30) having a front side and a back side, forming a membrane (31) over the front side of the substrate (30), forming a piezoelectric layer (18) over the membrane (31), forming at least one patterned conductive layer including first and second electrodes (19) in contact with an active portion of the piezoelectric layer (18), patterning the substrate (30) from the back side such that supports (40) partly comprising walls perpendicular or at least not parallel to the membrane (31) are obtained on adjacent sides of the active portion of the piezoelectric layer (18) and a trench (41) is provided underlying the active portion, wherein patterning the substrate (30) comprises dimensioning the trench (41) to achieve a higher ultrasound output on the support side than on the opposite side; optionally, forming a protection layer on top of the patterned conductive layer.