The importance of characterising the atomic structure of the silicon / silicon dioxide interface as an essential component in highly integrated circuits has steadily increased as a result of continuing miniaturisation of silicon chips. The physicists, Dr. Stefan Bergfeld, Bjoern Braunschweig and Prof. Dr. Winfried Daum, Institute of Physics and Physical Technologies at the Technical University of Clausthal, have succeeded in characterising the change in bond structure of interfacial atoms during the oxidation of a silicon surface by a purely optical method. The results of the research have been published in the scientific journal, Physical Review Letters, Volume 93, No. 9 (online on 27th August 2004).
In the present work, the atmospheric oxidation of a hydrogen-covered (111)-oriented silicon surface has been studied, and special bonding states of the silicon atoms have been identified. The scientists also observed these bonding states after the technically relevant thermal oxidation. For characterising the interfaces, the physicists apply a special nonlinear-optical method, with which the laser light is converted by interfacial atoms to photons with energies in the near ultraviolet range by doubling of the frequency. This purely optical spectroscopic method with frequency doubling allows nondestructive characterisation of the oxidation process under real conditions and also provides very high interfacial sensitivity, in comparison with other optical methods.
The Si(111)-SiO2 interface is a prime example of an abrupt transition from a perfect crystal structure to an amorphous oxide. In contrast to the technologically more relevant Si(100) surface, the surface of a (111)-terminated silicon crystal possesses a structure consisting of bi-layers, in which changes in the bond structure resulting from oxidation can be observed especially well.
Winfried Daum | alfa
Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory
SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences