Formation of cobalt silicide in Co+implanted Si(111)

摘要

The microstructural variation of CoSi2buried layers formed by 100 keV Co+implantation at 350thinsp;deg;C into Sithinsp;(111) is systematically studied. The critical dosedcof Co+implantation at 100 keV required to form a continuous CoSi2buried layer after annealing is the same in both Sithinsp;(111) and (001), ape;1.1times;1017cmminus;2, corresponding to a threshold peak concentration of 18.5 at.thinsp;percnt; Co. In addition, we observe continuous buried layers consisting of bothAhyphen;(fully aligned) andBhyphen;(twinned) CoSi2grains in the (111) samples implanted at doses ape;dc. The relative fractions ofAandBare found to vary with the implanted doses, current densities of the ion beam, and annealing conditions with theBfractions varying from 0percnt; to 100percnt;. ContinuousAhyphen;type layers are formed only in the samples implanted to doses ge;1.6times;1017cmminus;2.