Crosstalk study of an integrated ultrasound transducer array, with a micromachined diaphragm structure

The impact of micromachining on crosstalk effects in ultrasound transducer arrays on an Si chip was investigated. Three linear arrays with different substrate structures were designed and fabricated with Si micromachining: (1) solid substrate; (2) large diaphragm window; and (3) small diaphragm window (SW). Responses of transducer elements from each array were measured and the fast Fourier transform was performed to obtain the directivity pattern of these array elements at various frequencies. The data at 5 MHz were curve-fit to calculated directivity patterns based on an established crosstalk model with fours fitting parameters. These parameters allow a quantitative comparison of crosstalk characteristics of the three arrays. The curve-fit results indicate that the SW structure provides the best interelement isolation and thus the least crosstalk.<>