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Advances in Nano Research
  Volume 2, Number 1, March 2014 , pages 1-14

Dislocations as native nanostructures - electronic properties
Manfred Reiche, Martin Kittler, Hartmut Uebensee, Eckhard Pippel and Sigrid Hopfe

    Dislocations are basic crystal defects and represent one-dimensional native nanostructures embedded in a perfect crystalline matrix. Their structure is predefined by crystal symmetry. Twodimensional, self-organized arrays of such nanostructures are realized reproducibly using specific preparation conditions (semiconductor wafer direct bonding). This technique allows separating dislocations up to a few hundred nanometers which enables electrical measurements of only a few, or, in the ideal case, of an individual dislocation. Electrical properties of dislocations in silicon were measured using MOSFETs as test structures. It is shown that an increase of the drain current results for nMOSFETs which is caused by a high concentration of electrons on dislocations in p-type material. The number of electrons on a dislocation is estimated from device simulations. This leads to the conclusion that metallic-like conduction exists along dislocations in this material caused by a one-dimensional carrier confinement. On the other hand, measurements of pMOSFETs prepared in n-type silicon proved the dominant transport of holes along dislocations. The experimentally measured increase of the drain current, however, is here not only caused by an higher hole concentration on these defects but also by an increasing hole mobility along dislocations. All the data proved for the first time the ambipolar behavior of dislocations in silicon. Dislocations in p-type Si form efficient one-dimensional channels for electrons, while dislocations in n-type material cause onedimensional channels for holes.
Key Words
    dislocations; one-dimensional nanostructures; electronic properties; MOSFETs; semiconductor wafer bonding
Manfred Reiche, Eckhard Pippel and Sigrid Hopfe : Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle, Germany
Martin Kittler : IHP Microelectronics, Im Technologiepark 25, D-15236 Frankfurt (Oder), Germany
Hartmut Uebensee : CIS Research Institute of Microsensorics and Photovoltaics, K.-Zuse-Str. 14, D-99099 Erfurt, Germany

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