Design of piezoelectric micromachined ultrasonic transducers (pMUTs) for high pressure output

A novel design of piezoelectric micromachined ultrasonic transducers (pMUTs) with a fully free edge structure by introducing a deep trench between cells was proposed, and its performance was evaluated by finite element method in both time and frequency domains for the resonant frequency and acoustic pressure output. In comparison to current cell configurations of clamped and simply suspended boundaries, our design has a great increase in the output pressure. The effect of the covering area of piezoelectric material (i.e., AlN) was also investigated. It is found that when the piezoelectric layer has the same size as the cavity the generated acoustic pressure will reach its maximum value. Altogether, the newly designed structure of pMUTs has the potentials of high pressure applications (i.e., ultrasound therapy) if driven properly.