Research on barriers to energy efficiency of silicon carbide

Schematic representation of the irregular accumulations of carbon rings (black) at the interface between silicon dioxide and silicon carbide

A research group of the University of Basel, Department of Physics/Swiss Nanoscience Institute and the Paul Scherrer Institute (Switzerland) has found explanations for efficiency reductions of transistors made of silicon carbide. Such components are increasingly used in power electronics, including solar inverters, because they have a much higher heat resistance and energy efficiency than conventional silicon transistors. On the other hand, according to the research group, these advantages are »significantly compromised by defects at the interface between silicon carbide and the insulating material silicon dioxide«.
According to the scientists, these defects are caused by tiny carbon clusters bound in the crystal lattice. They are formed at high temperatures during the oxidation of silicon carbide to silicon dioxide. It is assumed that the defects could be reduced by changes in the production process. One possibility is a nitrous oxide atmosphere during the heating process, another is post-treatment with nitrogen. The experimental results on both the origin of the defects and the possible countermeasures were confirmed in computer simulations.

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