Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Surprise at the nanoscale: Silicon atoms jump after contact with metal


Max Planck researchers from Stuttgart reveal unknown behaviour of semi-conductors at the nanoscale

Silicon is presently the most proper ingredient for microelectronic devices: it serves as basic material for all current computer chips. According to the increasing importance of electronic set-ups, the term “Silicon Age” is widely-used nowadays.

Semiconductor atoms (as silicon and germanium atoms) get influenced by metal (as aluminium) at the nanoscale and change their position through atomic jumps, even at temperatures as low as -190 degree celsius.

© Dr. Zumin Wang, MPI-IS Stuttgart

Further, the nickname Silicon Valley, representing the high-tech region in California, indi-cates the enormous importance of silicon for the semi-conductor and computer industry.

Crystalline silicon has also been widely used for the production of TFT-flatscreens and is, furthermore, a fundamental basic material for the assembling of photovoltaic cells.

A further semiconductor is germanium, which initially was the leading material in (micro) electronics, until it was replaced by silicon. Only few years ago, researchers discovered that monolayers of germanium conduct electrons up to 10 times faster than silicon. For this reason, germanium could catch up as semi-conductor again.

Silicon and germanium are both quite heat resistant and melt only at temperatures higher than 900 degree Celsius. At the solid state, the atoms are positioned within a regularly or-dered crystal lattice and can only vibrate slightly at their respective locations. With increas-ing temperature, the vibrations intensify and even “jumps“ to different sites in the solid occur. At room temperature these kind of atomic jumps are practically impossible.

Scientists led by Prof. Dr. Ir. Eric Jan Mittemeijer, Director at the Max Planck Institute for Intelligent Systems in Stuttgart, have recently discovered that atomic jumps occur in silicon and germanium even at very low temperature of minus 190 degree Celsius, if the thin layer of only 1 nanometer (millionth millimeter) gets in contact with metal, e.g. alu-minium.

The researcher Dr. Zumin Wang reports: „We tried to prepare artificial sandwiches com-posed of a very thin, 1-nm silicon or germanium film between two aluminium layers at minus 190 degree celsius. During this process we figured out that germanium or silicon always moved to the top surface of the aluminium. It was not possible to prepare such sandwiches. First, we found this “behavior” quite annoying, but soon we recognized that we had made a very surprising observation.”

While using X-ray photoelectron spectroscopy, the scientists found out that the bonding characteristics within germanium- and silicon atoms become strongly influenced when they get in touch with metals at thin-film set-ups. As a consequence, the semi-conductor atoms become able to “jump” more frequently. Because of these jumps, the atoms get mobile and change their position: they jump to the top surface of the aluminium. The metal influ-ences this mobility and has to be as close as half a nanometer.

Dr. Wang states: “This observation could become even more important since assembly parts for computers made of semi-conductor material shrink increasingly. Currently they are already as small as 10 to 40 nanometer, which means that at slightly smaller scale, mixing effects due to atomic jumps may arise. Secondly, the discovered process has impact on the preparation of thin film systems involving heat-sensitive materials, since the semi-conductor can become mobile even at very low temperature.”

Weitere Informationen:

Annette Stumpf | Max-Planck-Institut für Intelligente Systeme

More articles from Materials Sciences:

nachricht Researchers demonstrate existence of new form of electronic matter
15.03.2018 | University of Illinois at Urbana-Champaign

nachricht Boron can form a purely honeycomb, graphene-like 2-D structure
15.03.2018 | Science China Press

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

TIB’s Visual Analytics Research Group to develop methods for person detection and visualisation

19.03.2018 | Information Technology

Tiny implants for cells are functional in vivo

19.03.2018 | Interdisciplinary Research

Science & Research
Overview of more VideoLinks >>>