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)

Publisher: Springer

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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.

Keywords: Ohmic contacts; silicon carbide (SiC); Schottky barrier height; epitaxy

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s11664-006-0083-3

Affiliations: 1: Email: lporter@andrew.cma.edu

Publication date: 2007-04-01