[mems-talk] recipe to reveal pn junction

[Roger Brennan]

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
roger at Solecon.com
775-853-5900 ext 108


-----Original Message-----
From: mems-talk-bounces at memsnet.org
[mailto:mems-talk-bounces at memsnet.org]On Behalf Of B Frank
Sent: Wednesday, August 02, 2006 5:49 PM
To: mems-talk at memsnet.org
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?