Dopant delineation in silicon

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2 total messages Started by Mikael Jargelius Fri, 10 Apr 1992 09:22

#132

Author: Mikael Jargelius
Date: Fri, 10 Apr 1992 09:22

20 lines
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Hi,

I am looking at polished or cleaved cross sections of silicon IC's using an
SEM.

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?
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Mikael Jargelius  -  mikael@inmic.se                  *
Swedish Institute of Microelectronics                 *     *        *
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Re: Dopant delineation in silicon

#134

Author: Tom Knight
Date: Sat, 11 Apr 1992 14:46

20 lines
1549 bytes

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.

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