CoSi2 microstructures by means of a high current focused ion beam

The Rossendorf focused ion beam IMSA-100 was contructed and used for writing implantation of cobalt to form CoSi2-submicron strutures on silicon by ion beam synthesis. Two types of cobalt containing liquid alloy ion source were developed with Co-Nd and Co-Ge alloys. The fabrication of CoSi2 structures by stoichiometric implantation of Co+ (E = 30-35 keV, Iion = 1.3 nA) and Co2+ ions (E = 60 keV, Iion = 0.6 nA) at doses between 0.3 and 5x1017 cm-2 and a subsequent two step annealing (600°C, 60 min; 1000°C, 30 min in N2) is demonstrated. The dose dependence as well as the influence of the substrate temperature between room temperature and 400°C during ion implantation on the ion beam synthesis process were studied. The quality of the silicide submicron structures was investigated by scanning electron microscopy, energy dispersive x-ray analysis, and electrical measurments. While the room temperature implantation and subsequent annealing generate an inhomogeneous CoSi2 film, 400°C substrate heating during implantation leads to a countinuous film with a resistivity below 20µ( cm, comparable with broad beam implantation.