SINCE ITS INVENTION, THE ELECTRON MICROSCOPE
HAS REVEALED THE DETAILS OF LIFE TO SCIENTISTS
Author: By David L. Chandler, Globe Staff
Date: Thursday, October 16, 1986
Page: 25
Section: METRO
The Nobel Prize in Physics was awarded yesterday for two developments in
electron microscopy, one made more than 50 years ago.
The electron microscope, a standard piece of equipment in most research
labs, uses an electron beam instead of light to form images. The electron
miscroscope was invented in 1933 by Ernst Ruska, who was attending the Berlin
Technical University in Germany.
Because an electron beam can be focused much more finely than a beam of
light, electron microscopes can produce images that reveal much more detail
than even the best optical microscopes.
But the scanning tunneling microscope, or STM, which uses a completely
different technology and was first used less than three years ago, can
revealeven finer detail, including the positions of individual atoms on a
surface.
The technique already has greatly improved the understanding of the
silicon surfaces used to make computer chips and may someday be adapted as a
way of manufacturing advanced chips, according to the Nobel committee.
Developed by Gerd Binnig and Heinrich Rohrer of the International Business
Machines Corp. research laboratory in Zurich, the STM uses a completely new
principle to produce images.
Rather than bouncing a beam from a surface -- as both light microscopes and
electron microscopes do -- the STM uses an extremely sharp-pointed stylus that
passes over the surface being studied without ever quite touching it.
The electrical repulsion of the individual atoms keeps the stylus
''suspended" above the surface because of a phenomenon called the tunneling
effect, which gives the device its name.
The stylus is then mechanically moved across the surface in a scanning
pattern. As it passes over each atom, the electrical force increases, causing
the stylus to move upward. The vertical movements of the stylus are
continuously recorded by a computer, which then uses the data to construct an
image of the surface.
The resulting images resemble pen-and-ink drawings of rippling waves on the
ocean. They are the first images ever made that can show the positions of
atoms on a densely packed surface.
The idea for the technique was developed five years ago, and the
researchers said yesterday that most of their colleagues thought they were
crazy.
CHANDL;10/15 NKELLY;10/16,14:14 SCOPE16
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