I am looking for a way of making 300 nm deep pyramid shaped pits in either
silicon or quartz.  The method does not need to be compatible with large
volume production.  I am interested in the angle and surface texture of the
pit.

I know that I can use anisotropic etching of 100 silicon to form such pits
but I am photolithography limited.  A 300 nm deep pit would require about a
400 nm sized opening in a mask or a subsequent deposition to narrow the
opening which would round the features.  Does anybody have experience with
depositing a film to reduce the size of an etch pit?  Can a sharp pyramid
feature by preserved?

I am interested in a foundry that could make the 400 nm sized mask
openings,  or another method of machining 300 nm deep pyramid shaped pits
in silicon or quartz.

Dan Chilcott
Delphi Delco
Advanced Sensor Development
765-451-7467