Dear mems Researchers,
 I am having trouble of how to do the electro chemical etch stop. Iam
not able to understand how to connect the positive eletrode to n-type
epilayer when my whole wafer is in the etchant of negative electrode.
Can some body give me a detailed process steps of electrochemical etch
stop, including the apparatus that i need to buy for this process.
Also tell me if any one have done the thesis on MEMS pressure sensors
using peizo effect. so that i can use as a reference for my project
  Thank you for any help in advance.
Regards,
Amith