Berlin 2008 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 34: Hard and Superhard Coatings
DS 34.1: Vortrag
Donnerstag, 28. Februar 2008, 15:45–16:00, H 2032
Doping of high quality c-BN films epitaxially grown on top of diamond(001) — •Hong Yin1, Xuyang Wang1, Ivan Pongrac1, Paul Ziemann1, Fabian Renaux2, Michel Hecq2, and Carla Bittencourt2 — 1Institut für Festkörperphysik, Universität Ulm, 89069, Ulm, Germany — 2University of Mons-Hainaut, B-7000 Mons, Belgium
Since it first synthesis in 1957 cubic Boron Nitride (c-BN) has attracted considerable interest due to its extreme physical and chemical properties. Besides as a superhard material second to diamond, it exhibits a wide band gap (6.4 eV) and high thermal conductivity making c-BN attractive as a high temperature electronic material. The recently achieved heteroepitaxial growth of c-BN films on top of diamond(001) [1] opened a promising window for e.g. c-BN/diamond pn-junctions. We will present results on the doping of high quality c-BN samples epitaxially grown onto diamond(001). XPS combined with ToF-SIMS results showed that metallic impurities within such epitaxial films are below several ppm leaving carbon and oxygen as the main impurities, which are homogeneously distributed inside the film. As a result, the nominally undoped c-BN films are p-type conducting as revealed by Hall effect. Si+ was chosen to dope these epitaxial c-BN films by either in-situ adding Si+ during film growth, or ex-situ doping by cold implantation and rapid thermal annealing (CIRA). In both cases, the electrical resistance of the samples is significantly decreased. Hall effect measurements indicate a related n-type conduction.
[1] X. W. Zhang et al., Nature Mater. 2 (2003) 312.