We have been using Phil-Tec Safe-T-Stain for some 30 years.  Put a drop on your
sample.  Focus it under a microscope (use a microscope objective with a
reasonable amount of working distance--say a 5X or 10X).  Watch n-type turn
dark.  Once you have enough definition, remove the sample and sling off or rinse
off the stain.  Air dry usually works but you can blow dry if you don't get too
aggressive.

If you leave the stain on too long, P+ can turn dark and confuse things.

Hope this helps.  Contact me directly if you wish.

Roger Brennan
Applications Director
Solecon Labs
770 Trademark Drive
Reno, NV 89521-5926
[email protected]
775-853-5900 ext 108


-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of B Frank
Sent: Wednesday, August 02, 2006 5:49 PM
To: [email protected]
Subject: [mems-talk] recipe to reveal pn junction


Hi, all
I am working on doping silicon wafer using boron diffusion.
But I don't know how to evaluate the doping depth.
I tried CP-4A(HNO3:HF:HAC=5:3:3) at room temperature to reveal the
interface between the p area and n area. The etching speed appears
very fast, seems not work.
Is there anyone has such experience?
Or how to reveal the interface?