US 7,321,181 B2 | ||
Capacitive membrane ultrasonic transducers with reduced bulk wave generation and method | ||
Butrus T. Khuri-Yakub, Palo Alto, Calif. (US); Arif S. Ergun, Mountain View, Calif. (US); and Goksen Yaralioglu, Mountain View, Calif. (US) | ||
Assigned to The Board of Trustees of the Leland Stanford Junior University, Palo Alto, Calif. (US) | ||
Filed on Apr. 04, 2005, as Appl. No. 11/98,863. | ||
Claims priority of provisional application 60/560789, filed on Apr. 07, 2004. | ||
Prior Publication US 2005/0236937 A1, Oct. 27, 2005 | ||
Int. Cl. H01L 41/08 (2006.01) |
U.S. Cl. 310—320 [310/324; 310/334] | 9 Claims |
1. The method of suppressing bulk wave generation at the frequency of operation of a cMUT of the type which includes a membrane supported above a substrate which comprises configuring the substrate to suppress bulk wave generation at the operating frequency wherein the substrate is configured by photolithographically patterning and etching a defined periodic pattern of grooves on a back side of the substrate with the groove depth being one quarter the wavelength of the bulk waves to be suppressed. |