In order to build ever smaller electronic circuits, the semiconductor industry will have some day to move from current lithography technologies to something different, such as molecular electronics. This new process is pioneered by a group of engineers at Northwestern University. They are using a scanning tunneling microscope (STM) to precisely align multiple types of molecules on a silicon surface at room temperature. Their nanofabrication process will soon lead to molecular transistors or light-emitting diodes. As this new process works at room temperature, this means it is possible to integrate it with current technologies. Putting it in another way, in some future, we'll still be able to look at the screens of our computers, but we'll not see the chips inside, even with a home microscope. Read more...
Here are selected excerpts from this news release.
"We have demonstrated a strategy for intentionally positioning molecules, which is necessary for the construction of nanoscale systems such as molecular transistors or light-emitting diodes," said Mark C. Hersam, assistant professor of materials science and engineering, who led the research team.
"Our process works at room temperature and on silicon, which suggests that it can be made compatible with conventional silicon microelectronics. Ultimately, we want to integrate with current technology, thus creating a bridge between microelectronics and nanoelectronics."
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Here is a rendering of an ultrahigh vacuum STM image of individual molecules known as TEMPO on a silicon surface. The following link to the Hersam Research Group, which is the owner of this image, will give you more explanations . |
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And here is another STM image of one-dimensional styrene chains on silicon surface, where the width of the chains is approximately 1 nm. (Credit: The Hersam Research Group). |
The nanofabrication process, called multi-step feedback-controlled lithography, is useful for a variety of fundamental studies and for the construction and testing of prototype nanoscale devices that could be used in future technologies ranging from consumer electronics to biomedical diagnostics.
The researchers demonstrated their process using a custom-built ultrahigh-vacuum scanning tunneling microscope. With this tool, they constructed chains consisting of styrene and a molecule known as TEMPO and now are studying the electronic properties of this novel nanostructure.
The research work has been published by Applied Physics Letters in its September 27, 2004 issue (Volume 85, Issue 13, pp. 2619-2621). Here is a link to the abstract of this paper named "Room temperature nanofabrication of atomically registered heteromolecular organosilicon nanostructures using multistep feedback controlled lithography." A title almost as long as the abstract...
Sources: Northwestern University news release, via EurekAlert!, September 27, 2004; and various other websites
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