From: Jeff Davis (jrd1415@yahoo.com)
Date: Wed Dec 25 2002 - 17:47:09 MST
Extropistas,
Big step toward molecular electronics
http://www.aip.org/tip/INPHFA/vol-8/iss-6/p9a.html
Love the increasing magnification photo sequence.
Denser. Non-volatile. Cheaper. And this is just the
very first generation. Ho, ho, ho indeed.
By the way, a question.
The article provides a link--
http://www.aip.org/tip/INPHFA/vol-8/iss-5/p9.pdf
--to "...a new imprinting process recently developed
by Princeton University physicists (see TIP Briefs,
October/November 2002, pp. 10-11).
That mini-article, entitled "Printing on Silicon",
cites the first(?) use of a nanoscale-etched quartz
mold--like that used by the Hewlett-Packard folks
above. But the Princeton use was different. They
shined a laser through the quartz and melted the
adjacent silicon, which then flowed into the etchings
in the mold and resolidified, creating the positive of
the etched negative.
*****Presumably, the resolidified silicon is still
single crystal.*****
Now here's my question.
Silicon chips require single crystal silicon, right?
This comes in slices--referred to as wafers--cut off a
single crystal ingot. Without looking into it to find
out why, I've always wondered at this seemingly
laborious--and, could it be, wasteful?--process.
I say wasteful, because, though I must confess to
being severely uninformed about this, it seems to me
that the purified silicon starting product is quite
expensive (I could be wrong), and in order to survive
the slicing process must be cut way thicker than
needed for the final chip (too thin is too delicate to
cut). These wafers are then ground to the appropriate
thickness and polished.
-----slight digression---------
I've actually done this once. Helped Novalux in
Sunnyvale set up their clean room, and ground a
gallium arsenide wafer from 450 microns starting
thickness to 150 microns final. One experience with
this hardly makes me well informed, but look at that
one case. Fully two-thirds of the material was ground
away!
-------end digression----------
Why are not the wafers made say, by compressing
powdered silicon between two polished flat quartz
discs and then melting the sandwiched particles
together using the same laser melting technique
described in "Printing on Silicon"? Or, why is not
amorphous silicon made single crystal by some such
similar process?
Normally, I wouldn't ask, but I had only a few minutes
to kill before going off to >Hmas dinner, so rather
than some few pleasant hours googling up the answer,
and otherwise joyfully exploring the realms of arcane
technoweeniedom--it's what I do--I decided to pose it
as a question to y'all. "Show me the magic."
No pressure. Ponder, discourse upon, or ignore,...as
pleases you. Or throw me a link or two.
Onward then, "to horizons of love or good luck,... or
more love."
Best, Jeff Davis
"You are what you think."
Jeff Davis
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