Enhanced formation of periodic arrays of low-resistivity NiSi nanocontacts on (0 0 1)Si 0.7 Ge 0.3 by nanosphere lithography with a thin interposing Si layer

In this study, we demonstrated significant enhancement of the formation of low-resistivity NiSi nanocontacts with controlled size on (0 0 1)Si0.7Ge0.3 substrates by combining the nanosphere lithography with the use of a new Ni/a-Si bilayer nanodot structure. Low-resistivity NiSi with an average size of 78 nm was observed to be the only silicide phase formed in samples annealed at 350-800 degrees C. The presence of the interposing Si layer with appropriate thickness was found to effectively prevent Ge segregation and maintain the interface stability in forming NiSi nanocontacts on (0 0 1)Si0.7Ge0.3. As the annealing temperature was increased to 900 degrees C, amorphous SiOx nanowires were observed to grow from silicide nanocontact regions. The NSL technique in conjunction with a sacrificial Si interlayer process promises to be applicable in fabricating periodic arrays of other low-resistivity silicide nanocontacts on Si1-xGex substrates without complex lithography. (C) 2011 Elsevier B.V. All rights reserved.