Fabio,

It will depend on how you specify the glass.  Do you need a flat?  Defect level?
Both sides defect free?  Any holes?
For more information contact Bullen Ultrasonics 4613 Camden Road Eaton, OH 45320
USA
937-456-7133
www.bullen-ultrasonics.com

 Dielectric Constant for Si3N4 is 7.5

Joe Brown

Joe Brown
MEMS
Karl Suss America
jbrown@suss.com
802-244-5181X250
802-244-5103 Fax