Chemical Bonding States at Silicon / Silicon Dioxide Interfaces Characterisable with Light

Aug 27, 2004

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.

Source: Technical University Clausthal

Explore further: How bubble studies benefit science and engineering

add to favorites email to friend print save as pdf

Related Stories

We are all made of stars

22 minutes ago

Astronomers spend most of their time contemplating the universe, quite comfortable in the knowledge that we are just a speck among billions of planets, stars and galaxies. But last week, the Australian astronomical ...

Netflix unveils new way to share recommendations

22 minutes ago

Netflix is giving its Internet video subscribers a more discreet way to recommend movies and TV shows to their Facebook friends after realizing most people don't want to share their viewing habits with large audiences.

How bubble studies benefit science and engineering

24 minutes ago

The image above shows a perfect bubble imploding in weightlessness. This bubble, and many like it, are produced by the researchers from the École Polytechnique Fédérale de Lausanne in Switzerland. What ...

How financial decisions are made

12 minutes ago

Jayant Kale didn't grow up dreaming of becoming a leading expert in corporate finance and mutual fund investment. But he's happy he invested in that market early in life.

Recommended for you

New method for non-invasive prostate cancer screening

11 hours ago

Cancer screening is a critical approach for preventing cancer deaths because cases caught early are often more treatable. But while there are already existing ways to screen for different types of cancer, ...

How bubble studies benefit science and engineering

12 hours ago

The image above shows a perfect bubble imploding in weightlessness. This bubble, and many like it, are produced by the researchers from the École Polytechnique Fédérale de Lausanne in Switzerland. What ...

Famous Feynman lectures put online with free access

13 hours ago

(Phys.org) —Back in the early sixties, physicist Richard Feynman gave a series of lectures on physics to first year students at Caltech—those lectures were subsequently put into print and made into text ...

Single laser stops molecular tumbling motion instantly

17 hours ago

In the quantum world, making the simple atom behave is one thing, but making the more complex molecule behave is another story. Now Northwestern University scientists have figured out an elegant way to stop a molecule from ...

User comments : 0