Colleagues: Currently,we are designing a silicon micromachined, electrostatic, ultrasonic air transducer for a biomedical application. A crucial part of the design is a flexible diaphragm made of silicon nitride. At this point, we need to perform a rupture test on silicon nitride membranes to see at what pressures they burst. The dimensions of the membranes being considered vary in thickness from 0.1 to 0.5um and in width from 25um to 3mm. First, we are checking to see if this rupture test has already been done on silicon nitride membranes. If anyone has any information on the burst pressure of these membranes, please contact us by email or at the address below. Thanks for your help. Prof. Richard B. Fair David Cretella Dept. of Electrical Engineering Phone : (919) 660-5294 Duke University Fax : (919) 660-5293 Box 90291 Durham, NC 27708-0291