micro devices are formed in situ in a high density in a substrate comprising a masked silicon layer over a stop layer of a silicon compound , by anisotropically etching the desired feature in the silicon layer , overetching to form a notch at the silicon - stop layer interface , depositing a protective fluorocarbon polymer layer on the sidewalls and bottom of the etched silicon layer , and isotropically etching to separate the etched feature from the stop layer . this method avoids the problems of stiction common in other methods of forming micro devices .