Erbium Silicide Formation on Si[sub 1−x]C[sub x] Epitaxial Layers

Erbium silicide ( Er Si 2 − x ) formation was investigated on Si 1 − x C x 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 ° C . The sheet resistance of the silicide films formed on Si 1 − x C x epitaxial layers was found to be equal to or less than the sheet resistance of the films formed on Si epitaxial layers. At 600 ° C , an average resistivity of 114 ± 4 μ Ω 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 Er Si 2 − x ∕ Si 1 − x C x interface with no carbon incorporation in the silicide. The films formed on Si 1 − x C x 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.