🚀 go-pugleaf

In article <1992Apr10.092224.20684@sics.se> mikael@inmic.se (Mikael Jargelius) writes:

   In order to obtain contrast between layers I use different wet chemical
   etchants, e.g. diluted HF for aluminium, buffered HF for silicon dioxide etc.

   Now, I would like to know if there are any good suggestions for methods to use
   to obtain delineation of doped regions in silicon. I have used Sponheimer-
   Mills and Rowe etchants and got useful results for high dopant concentrations,
   but I would also like to detect lower dopant levels in a reproducible way.

   Perhaps some kind of plating could do the job?

You might check out the (probably out of print) book "Semiconductor
Measurements and Instrumentation", by WR Runyan, McGraw-Hill '75.  It
has a discussion on visualization stains.  I believe their suggestions
included adding very small amounts of cupric nitrate to the buffered HF
to decorate the diffused regions.

If anyone knows effective techniques for removing metal-2 without
removing metal-1, I'd be grateful for some hints.