Perfect silicon disks - BASF.com

Science around us
A news service provided by BASF
Perfect silicon disks
Microchip manufacturers rely on high purity BASF chemicals
Christian Böhme
Corporate Media Relations
phone +49(0)621 60-20130
P 104e
From beach sand to computer chip
The Info Box
Silicon (from the Latin silex meaning ‘flint’) is the second most abundant element in
the earth’s crust after oxygen and is contained in most minerals. Elemental silicon is a
semiconductor. Its electronic properties can be modified in a targeted fashion by
introducing foreign atoms, a process called doping. Silicon is widely used in microelectronics
and solar cell technology.
The Czochralski method is the technology used to grow the large crystals required
in the chip industry. A tiny but perfectly formed crystal is immersed in a melted purified
silicon bath that is only slightly warmer than the melting point. If the crystal is removed
from the molten silicon carefully enough, silicon atoms will remain attached. The attached
atoms align themselves precisely to the structure of the little seed crystal. The
process results in the growth of ideal monocrystals up to two meters tall. The method
was named after the Polish scientist Jan Czochralski who discovered it by serendipity
in 1916 after accidentally dipping his quill into a tub of molten metal instead of an inkpot.
Hydroxylamine is a colorless crystalline compound produced from nitrates and
hydrogen. BASF is the world’s only supplier of pure hydroxylamine in the form of a
50 percent aqueous solution. The 7,000 tonne production capacity in Ludwigshafen is
enough to supply the entire global microchip industry, where the compound is used to
clean chips after etching.
Transistors switch an electric current on or off between two connectors, depending
on the voltage applied to a third connector attached to the respective transistor. They
can also increase the flow of current. Silicon-based microchip transistors are very fast
switchers, economical and tiny. Modern computers could not have been developed
without them.
Further information can be found at:
http://www.intel.com/pressroom/kits/manufacturing/making_a_chip_bkgrnd.htm
http://www.siltronic.com/internet/webcache/de_DE/Products/Poster_2004.pdf
http://en.wikipedia.org/wiki/Microprocessor
Text, photography and illustration are available at:
www.basf.de/science_around_us
Links to third-party sites (“hyperlinks”)
do not constitute an endorsement of
such third-party sites by BASF and
BASF is not responsible for the availability
of these sites or their contents.
The hyperlinking to these sites is at
the user’s own risk.