Joseph,
The Microelectronics center of North Carolina has a wafer supply service in
which I believe thay include silicon nitride.  They can be found on the web
at mems.mcnc.org.

Good Luck,

John Karpinsky

At 12:10 AM 2/18/98 -0600, you wrote:
>Hi folks,
>I wonder if anyone knows how to grow low stress silicon nitride
>for Xray mask membrane use?  Or if anyone knows places that can grow high
>quality low stress silicon nitride membrane for a cost?  Any info is
>appreciated and can help out all UW-Madison X-ray research groups greatly.
>
>Thanks
>Joseph Su
>