Erbium Silicide Formation on Si1-xCx Epitaxial Layers

Erbium silicide (ErSi2-x) formation was investigated on Si1-xCx epitaxial layers grown on Si substrates. Substitutional carbon incorporation in the epitaxial layers was in the range of 0.6-1.6%. The silicide films were formed by rapid thermal annealing of sputter-deposited erbium layers in the temperature range of 350-700 degrees C. The sheet resistance of the silicide films formed on Si1-xCx epitaxial layers was found to be equal to or less than the sheet resistance of the films formed on Si epitaxial layers. At 600 degrees C, an average resistivity of 114 +/- 4 mu Omega cm was obtained. The silicide grains were found to be epitaxially aligned to the substrate along the (100) orientation, regardless of the carbon concentration in the underlying epitaxial layer. Compositional analysis of the films indicated carbon accumulation at the ErSi2-x/Si1-xCx interface with no carbon incorporation in the silicide. The films formed on Si1-xCx epitaxial layers exhibited a smooth interface/surface morphology free of pinholes, contrary to the silicides formed on Si. The root-mean-square surface roughness was found to be less than 1.5 nm, which was found to be the case with both substitutional and interstitial incorporation of carbon atoms in the epitaxial layer. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3097189] All rights reserved.