> Do anyone know how to do cross section photo of um membrane via SEM?
>
> Thanks your help so much.
>
> Jacob

You can use a focused ion beam (FIB) to remove a section of a suspended
membrane and examine the cross section by SEM.  A number of academic and
commercial labs offer this service, I've had very good results using
Evans Analytical (google "evans analytical fib").

John Maloney
Senior MEMS Engineer
MicroCHIPS, Inc.
http://www.mchips.com