Partial epitaxial growth of NbSi 2 on Si(111)

Abstract

Transmission electron microscopy and Auger electron spectrometry have been applied to study the growth of NbSi 2 epitaxially on Si(111). Two distinct modes of NbSi 2 epitaxy were identified in samples annealed at 1100 °C for 1 h. The orientation relationships between epitaxial NbSi 2 and the silicon substrate were identified to be NbSi 2[1 100]// Si[111], NbSi 2(0003)// Si(22 4) and NbSi 2[1 100]// Si[111] , NbSi 2(0003)// Si(2 20) for mode A and mode B epitaxy, respectively. For mode A epitaxy, interfacial dislocations, 40–80 nm in spacing, were identified to be of edge type with 1 6 〈112〉 Burghers' vectors. No interfacial dislocations were observed for mode B epitaxy. Two-step annealings were found to be effective in improving the surface coverage of NbSi 2 islands on silicon. Intermixing of niobium and silicon atoms near the original NbSi interface was detected as a result of the first-step annealing. The silicide epitaxy was found to correlate well with the lattice match at the NbSi 2Si interface in the epitaxial growth of NbSi 2 on Si(111).