Low-loss scanning electron microscopy can be used to investigate the
surface topography of solid specimens and provides enhanced image contrast
over secondary electron images. A high resolution-condenser objective lens
has allowed the low-loss technique to resolve separations of Au nucleii of
50Å and smaller dimensions of 25Å in samples coated with a fine grained
carbon-Au-palladium layer. An estimate of the surface topography of fine
grained vapor deposited materials (20 - 100Å) and the surface topography of
underlying single crystal Si in the 1000 - 2000Å range has also been
investigated. Surface imaging has also been performed on single crystals
using diffracted electrons scattered through 10−2 rad
in a conventional TEM. However, severe tilting of the specimen is required
which degrades the resolution 15 to 100 fold due to image
forshortening.
Investigation of synthetic aperture methods in ultrasound surface imaging using elementary surface types