Characterization of Epitaxial Indium Nitride Interlayers for Ohmic Contacts to Silicon Carbide
Authors: Mohammad, F.; Cao, Y.; Porter, L.
Source: Journal of Electronic Materials, Volume 36, Number 4, April 2007 , pp. 312-317(6)
Abstract:Ohmic contacts to n-type 4H- and 6H-SiC without postdeposition annealing were achieved using an interlayer of epitaxial InN beneath a layer of Ti. The InN films were grown by reactive dc magnetron sputtering at 450°C, whereas the Ti films were deposited by electron-beam evaporation at room temperature. The InN films were characterized by x-ray diffraction (XRD), secondary electron microscopy (SEM), cross-sectional transmission electron microscopy (TEM), and Hall-effect measurements. Both XRD and TEM observations revealed that the Ti and InN films have epitaxial relationships with the 6H-SiC substrate as follows: (0001)[ <EquationSource Format="TEX"><![CDATA[$$ 11bar 20 $$]]></EquationSource> ]Ti∥(0001)[ <EquationSource Format="TEX"><![CDATA[$$ 11bar 20 $$]]></EquationSource> ]InN∥(0001)[ <EquationSource Format="TEX"><![CDATA[$$ 11bar 20 $$]]></EquationSource> ]6H-SiC. The Ti/InN/SiC contacts displayed ohmic behavior, whereas Ti/SiC contacts (without an InN interlayer) were nonohmic. These results suggest that InN reduces the Schottky barrier height at the SiC surface via a small conduction-band offset and support previous reports of an electron accumulation layer at the surface of InN.
Document Type: Research article
Publication date: 2007-04-01