ISSN 1063-7826, Semiconductors, 2009, Vol. 43, No. 7, pp. 865–871. © Pleiades Publishing, Ltd., 2009. Original Russian Text © O.A. Ageev, A.E. Belyaev, N.S. Boltovets, V.N. Ivanov, R.V. Konakova, Ya.Ya. Kudryk, P.M. Lytvyn, V.V. Milenin, A.V. Sachenko, 2009, published in Fizika i Tekhnika Poluprovodnikov, 2009, Vol. 43, No. 7, pp. 897–903. 865 1. INTRODUCTION The mechanisms of charge transport in barrier structures have already been studied for more than 50 years both from the standpoint of diagnostics and analysis of the electrical properties of semiconducting materials (structural-impurity heterogeneities, deep center parameters), and as it regards to the quality and reliability of semiconductor devices [1–6]. Theoreti- cal and experimental studies in this area have largely contributed to the knowledge of the fundamental properties of spatially inhomogeneous structures and promoted the development of modern electronics. In the last decade, the interest in specific features of charge transport in ohmic and barrier contacts has pronouncedly increased because of the development of new semiconductor technologies and wide-gap semiconductor materials for extreme electronics. Despite the advances in the technology of wide-gap materials, dislocations remain the main structural defects in these materials, and especially in hetero- junctions. The contribution of dislocations to the for- mation of excess currents in wide-gap heterojunctions based on III–V compounds was studied in [7, 8]. In [9–11], specific features of charge transport were stud- ied with account of the high dislocation density in ohmic contacts to GaP and GaN. In [12, 13], tunneling cur- rents were examined in silicon carbide p–n junctions and p-Si–n-3C-SiC heterostructures. A specific feature of the studies [7, 8, 12, 13] is that the tunneling currents were examined in wide (nondegenerate) p–n homo- junctions and heterojunctions. A similar model was suggested in [7] for Au–n- GaP–n-Si surface-barrier structures. The key role of dislocations in the charge transport and degradation of gallium nitride light-emitting diodes was noted in [14–16]. An attempt to take into account the role of disloca- tions artificially introduced by scratching the SiC sur- face in the charge transport was made in [17] in an analysis of the forward current–voltage (I–V) charac- teristics of diodes of silicon carbide’s Schottky barri- ers. However, the contribution of the high density of growth dislocations to the mechanism of charge trans- port in barrier contacts of SiC has not been studied in detail. The present study is concerned with the mecha- nism of charge transport in a diode of a silicon car- bide’s Schottky barrier formed by a quasi-amorphous interstitial phase of TiB x and ZrB x in their deposition by magnetron sputtering of compacted targets onto the surface of n-6H-SiC (0001) single crystals, prelim- inarily subjected to a photon cleaning. A rapid thermal annealing (RTA) of such barrier contacts at a temper- ature T a = 1000°C does not create additional phases and compounds formed with SiC by the components used for metallization. The electrical characteristics of contacts of this kind must be determined by the bulk properties of SiC. 2. EXPERIMENTAL As the starting material, we used Lely-grown n-6H- SiC single crystals with an uncompensated donor SEMICONDUCTOR STRUCTURES, INTERFACES, AND SURFACES Au–TiB x –n-6H-SiC Schottky Barrier Diodes: Specific Features of Charge Transport in Rectifying and Nonrectifying Contacts O. A. Ageev a , A. E. Belyaev b , N. S. Boltovets c , V. N. Ivanov c , R. V. Konakova b ^, Ya. Ya. Kudryk b , P. M. Lytvyn b , V. V. Milenin b , and A. V. Sachenko b a Taganrog Technological Institute of the Southern Federal University, Taganrog, 347924, Russian Federation b V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Kiev, 03028 Ukraine ^e-mail: konakova@isp.kiev.ua c State Enterprise Research Institute “Orion”, Kiev, 03057 Ukraine Submitted August 21, 2008; accepted for publication October 1, 2008 Abstract—Mechanism of charge transport in a diode of a silicon carbide’s Schottky barrier formed by a quasi-amorphous interstitial phase TiB x on the surface of n-6H-SiC (0001) single crystals with an uncompen- sated donor (nitrogen) concentration of ~10 18 cm –3 and dislocation density of ~(10 6 –10 8 ) cm –2 has been studied. It is demonstrated that, at temperatures T  400 K, the charge transport is governed by the tunneling current along dislocations intersecting the space charge region. At T > 400 K, the mechanism of charge trans- port changes to a thermionic mechanism with a barrier height of ~0.64 eV and ideality factor close to 1.3. PACS numbers: 73.25.+y, 73.40.Cg, 74.40.Ei, 73.40.Gk DOI: 10.1134/S1063782609070070