Groundbreaking work by scientists from Switzerland, Finland and Germany has
lead to a new world record in X-ray microscopy. For the first time ever, features
below 10 nanometres (nm) in width were resolved.
Key to this new world record was doubling of the effective line density of
FZP template (Fresnel Zone Plate, a key component of an X-ray microscope) by
extremely conformal thin films created through the use of Atomic Layer Deposition
(ALD). ALD work was carried out with a Picosun SUNALE™ R-150 reactor at
the premises of the University of Helsinki’s Laboratory of Inorganic Chemistry.
One of the Finnish scientists, Dr Tero Pilvi, has since joined the staff of
as Technical Sales Manager.
October issue of Ultramicroscopy Journal carries an article ”Advanced
thin film technology for ultrahigh resolution X-ray microscopy” by Joan
Vila-Comanala, Jörg Raabe and Christian David from the Swiss Paul Scherrer
Institute, the brand new holder of the X-ray microscopy spatial world record,
Mikko Ritala and Tero Pilvi from the University of Helsinki, Konstantin Jefimovs
from Eidgenössische Materialprüfungs- und Forschungsanstalt (EMPA,
Swiss Federal Laboratories for Materials Testing and Research) in Switzerland,
Rainer H. Fink from Friedrich-Alexander Universität in Germany, Mathias
Senoner from the German Bundesanstalt für Materialforschung und -prüfung
(BAM, Federal Institute for Materials Research and Testing), and Andre Maassdorf
from Ferdinand-Braun-Institut für Höchstfrequenztechnik (Ferdinand-Braun
Institute for High-Frequenzy Technology) in Germany.
The technology of X-ray microscopy was discovered some 100 years ago. It is
a preferred technology for high-resolution imaging of biological and inorganic
materials. X-ray microscopy can study materials at extreme nano-levels. Technology
has, however, limited the useful ability to study features below 25 to 30 nm
in width. For the past whole decade, the resolution of X-ray microscopy has
been stagnated at this level. Some successful results have been reported at
the 15 nm level, but these have not produced the required reproducibility to
become really useful. The Swiss-Finnish-German group has finally solved the
ALD is a thin film method which enables completely controlled growth of extremely
conformal films through its signature self-limiting, sequential surface reactions.
ALD produces complex layer structures with atomic level accuracy. ALD processes
can be reproduced with stunning accuracy.
The group produced a modified FZP with structures based on the conformal deposition
of high refractive index material by ALD onto the sidewalls of a pre-patterned
template made from a low refractive index material. This new focusing structure
achieves an unprecedented spatial resolution in X-ray microscopy. Line widths
of down to 9 nm were successfully resolved.
X-ray microscopy serves biology, biomedicine and materials science. The resolution
of X-ray microscopy is between that of the traditional optical microscope and
the electron microscope. The main advantage of X-ray microscopy over electron
microscopy is that it can view biological samples in their natural state. X-ray
microscopy produces higher penetration power and can inspect much thicker samples
than comparable methods can. X-ray microscopy is also capable of producing three-dimensional
tomograms of individual cells of living organisms.
Picosun develops and manufactures Atomic Layer Deposition (ALD) reactors for
micro- and nanotechnology applications. Picosun represents continuity to over
three decades of ALD reactor manufacturing in Finland. Picosun is based in Espoo,
Finland and has its US headquarters in Detroit, Michigan. SUNALE™ ALD
process tools are installed in various universities, research institutes and
companies across Europe, USA and Asia. The inventor of ALD, Dr. Tuomo Suntola,
is a member of the Board of Directors of Picosun. Picosun is a part of Stephen
Industries Inc. Oy.