Spreading resistance is used routinely for this kind of profiling.  We have
been pioneers of this service since 1974.  Please check out our website or
contact me.  Spreading resistance actually determines resistivity-depth and
then the carrier concentration-depth is calculated from published mobility
values.  SIMS should also be effective for this analysis but I believe more
expensive than spreading resistance.  Although Electrochemical CV does a
good job profiling several of the compound semiconductors, we did not find
it very good for silicon.

Roger Brennan
Applications Director
Solecon Labs
770 Trademark Drive
Reno, NV 89521-5926
Work: roger@Solecon.com
Work: 775-853-5900 ext 108
www.solecon.com

-----Original Message-----
From: mems-talk-bounces@memsnet.org
[mailto:mems-talk-bounces@memsnet.org]On Behalf Of Guangchi Archie Xuan
Sent: Friday, August 10, 2007 10:59 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Techniques for Dopant Profiling in Si


Hi, Colleagues,
        I am interested in obtaining the dopant profile in Si. It's just
normal diffusion process of Phosphorus or Boron into opposite type Si
substrate and form a p-n junction. And I need to find out that dopant
profiling -- usually is within a couple of microns.
        I look into this subject a little bit and basically for low cost and
reliable methods there are  1. Electrochemical C-V      2. Spreading
Resistance    3. SIMS.
       I know some of the pros and cons among them but since I have never
done depth profiling work before, I'm sure there are some tricks here and
there.
       Can you comment on the pros and cons for measuring the dopant
profiles of the above mentioned p-n structure? The lowest resolution I can
live with is huge and is around 25nm. But the Si quality is not good with
lot of defects, traps etc. and the surface might be rough on the order of
microns.

       Thanks!