Study of planarization of cobalt silicide lines and silicon surfaces by scanning force microscopy and scanning electron microscopy

Fine lines of 1.5-μm-wide and 80-nm-thick Co were patterned by a lithographic technique and deposited by electron gun onto (100) Si surfaces. Reacting the Co and Si to form CoSi2 lines was carried out at 600°C in He atmosphere. The composite surface consisting of alternating silicides and Si as seen by scanning electron microscopy showed qualitatively that the silicide lines have sunk completely into the Si and the entire surface appears planar. Quantitative changes in vertical direction before and after the formation of the silicide lines have been measured by atomic force microscopy.