Fig. 2: The structure of the PMUT device.
From: High frame rate ultrasonic flowmeter based on PMUT array with bidirectional acoustic beams
a The fabrication process of the PMUT. b The microscope photo of the PMUT. c The layer properties of the PMUT. d The scanning electron microscope (SEM) image of the PMUT. Five adjacent channels constitute the TX PMUT phased array, with each of them consisting of three PMUT cells. Multi-layer protection layer, vias connection, patterned bottom electrode and etching isolation were adopted to reduce mechanical and acoustic crosstalk
