Metal silicides are now used extensively in very-large-scale-integrated (VLSI) electronics due to their low resistivity, good thermal stability, and ability to form on Si. Of these silicides, yttrium silicide, YSi2-x has essentially 0% lattice mismatch with (111)Si, a low Schottky barrier height on n-type Si, and a unit cell based on the AlB2-type structure, but with 15-20% vacancies on the Si sublattice. Recent investigations of high-temperature ion implantation of yttrium ions into Si have emphasized the formation of buried-silicide layers. This study is focussed on the microstructure and defects in the vicinity of buried YSi2-x layers formed by Y-ion implantation into Si.Yttrium-silicide buried layers were formed by implanting 330 or 660 keV Y ions into (11l)Si substrates held at 450°C followed by a 1000°C, 1-hour vacuum anneal. The implant fluences varied from 1 to 3.6×l017 Y/cm2. Cross-section transmission electron microscopy (XTEM) analysis was carried out using a JEOL 4000EX electron microscope operating at 400 kV.
In-situ observation of self-cleansing phenomena during ultra-high vacuum anneal of transition metal nitride thin films: Prospects for non-destructive photoelectron spectroscopy
