WAFER BOND CMUT ARRAY WITH CONDUCTIVE VIAS

摘要

An integrated CMUT structure comprises a CMUT array (2), signal processing circuitry (7) and a first acoustic layer (8). The signal processing circuitry (7) is provided between the CMUT layer (2) and the first acoustic layer (8) and a second acoustic layer (4) is provided between the CMUT array (2) and the signal processing structure (7). The second acoustic layer (4) is provided directly adjacent the CMUT array layer (2). The CMUT array is a wafer-bonded CMUT array comprising a plurality of CMUT elements (3) distributed across a substrate. Each element comprises a cavity and a signal electrode formed in the substrate. A conductive membrane closes the cavity and forms a ground electrode. The membranes of the individual elements form an unbroken ground plane across the surface of the array. Electrical connection to the signal electrodes is provided by means of a conductive vias through the substrate from the signal electrode to the rear of the substrate.